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Sample records for antibiotic tolerant pseudomonas

  1. 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...

  2. 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.

  3. 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

  4. Selective proteomic analysis of antibiotic-tolerant cellular subpopulations in pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Babin, Brett M.; Atangcho, Lydia; van Eldijk, Mark B.

    2017-01-01

    involved in central carbon metabolism. We differentiated the immediate proteomic response, characterized by an increase in flagellar motility, from the long-term adaptive strategy, which included the upregulation of purine synthesis. This targeted, selective analysis of a bacterial subpopulation...... amino acid tagging (BONCAT) method to enable selective proteomic analysis of a Pseudomonas aeruginosa biofilm subpopulation. Through controlled expression of a mutant methionyl-tRNA synthetase, we targeted BONCAT labeling to cells in the regions of biofilm microcolonies that showed increased tolerance...... demonstrates how the study of proteome dynamics can enhance our understanding of biofilm heterogeneity and antibiotic tolerance. IMPORTANCE Bacterial growth is frequently characterized by behavioral heterogeneity at the single-cell level. Heterogeneity is especially evident in the physiology of biofilms...

  5. Antibiotic tolerance and microbial biofilms

    DEFF Research Database (Denmark)

    Folkesson, Anders

    Increased tolerance to antimicrobial agents is thought to be an important feature of microbes growing in biofilms. We study the dynamics of antibiotic action within hydrodynamic flow chamber biofilms of Escherichia coli and Pseudomonas aeruginosa using isogenic mutants and fluorescent gene...... expression reporters and we address the question of how biofilm organization affects antibiotic susceptibility. The dynamics of microbial killing is monitored by viable count determination, and confocal laser microscopy. Our work shows that the apparent increased antibiotic tolerance is due to the formation...... of antibiotic tolerant subpopulations within the biofilm. The formation of these subpopulations is highly variable and dependent on the antibiotic used, the biofilm structural organization and the induction of specific tolerance mechanisms....

  6. Reverting antibiotic tolerance of Pseudomonas aeruginosa PAO1 persister cells by (Z-4-bromo-5-(bromomethylene-3-methylfuran-2(5H-one.

    Directory of Open Access Journals (Sweden)

    Jiachuan Pan

    Full Text Available BACKGROUND: Bacteria are well known to form dormant persister cells that are tolerant to most antibiotics. Such intrinsic tolerance also facilitates the development of multidrug resistance through acquired mechanisms. Thus persister cells are a promising target for developing more effective methods to control chronic infections and help prevent the development of multidrug-resistant bacteria. However, control of persister cells is still an unmet challenge. METHODOLOGY/PRINCIPAL FINDINGS: We show in this report that (Z-4-bromo-5-(bromomethylene-3-methylfuran-2(5H-one (BF8 can restore the antibiotic susceptibility of Pseudomonas aeruginosa PAO1 persister cells at growth non-inhibitory concentrations. Persister control by BF8 was found to be effective against both planktonic and biofilm cells of P. aeruginosa PAO1. Interestingly, although BF8 is an inhibitor of quorum sensing (QS in Gram-negative bacteria, the data in this study suggest that the activities of BF8 to revert antibiotic tolerance of P. aeruginosa PAO1 persister cells is not through QS inhibition and may involve other targets. CONCLUSION: BF8 can sensitize P. aeruginosa persister cells to antibiotics.

  7. High-level tolerance to triclosan may play a role in Pseudomonas aeruginosa antibiotic resistance in immunocompromised hosts: evidence from outbreak investigation

    Directory of Open Access Journals (Sweden)

    D'Arezzo Silvia

    2012-01-01

    Full Text Available Abstract Background and methods Pseudomonas aeruginosa is a major infectious threat to immunocompromised patients. We recently reported a fatal epidemic of multidrug-resistant P. aeruginosa in an onchoematology unit, linked to massive contamination of a triclosan-based disinfectant. The aim of this study is to evaluate the antimicrobial activity of triclosan and chlorhexidine digluconate against the epidemic strain of P. aeruginosa, to confirm the hypothesis that the soap dispenser acted as a continuous source of the infection during the outbreak, and to explore the potential role of triclosan in increasing the level of resistance to selected antibiotics. Susceptibility tests and time-kill assays for disinfectans were performed using two commercial formulations containing triclosan and chlorhexidine digluconate, respectively. Antibiotic susceptibility testing was performed by the broth microdilution method. Findings The P. aeruginosa epidemic strain exhibited an extremely high level of triclosan resistance (apparent MIC = 2,125 mg/L, while it was markedly susceptible to chlorhexidine digluconate (apparent MIC = 12.5 mg/L. Upon gradual adaptation to triclosan, the epidemic strain survived for a long period (> 120 h in the presence of 3,400 mg/L (equivalent to 1.6 × MIC of triclosan, concomitantly increasing the resistance to six antibiotics that are typical substrates of drug efflux pumps of the resistance nodulation division family. This effect was reversed by efflux pump inhibitors. Conclusions The epidemic P. aeruginosa strain was resistant to triclosan and its previous exposure to triclosan increases antibiotic resistance, likely through active efflux mechanisms. Since P. aeruginosa can become tolerant to elevated triclosan concentrations, the use of triclosan-based disinfectants should be avoided in those healthcare settings hosting patients at high risk for P. aeruginosa infection.

  8. 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.

  9. 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...

  10. Distribution, diversity, and activity of antibiotic-producing Pseudomonas spp.

    NARCIS (Netherlands)

    Souza, de J.T.

    2002-01-01

    Bacteria of the genus Pseudomonas are potential biocontrol agents of plant diseases caused by various fungi and oomycetes. Antibiotic production is an important trait responsible for the activity of several Pseudomonas

  11. Antibiotics profiling of Proteus mirabilis and Pseudomonas ...

    African Journals Online (AJOL)

    Constant tracking of the antibiotic susceptibilities of these organisms at different region within each country is of great epidemiological value to formulate well informed and scientific based preventive measures to curtail the spread of drug resistant pathogens through the food chain. We screened 19 Proteus mirabilis and 35 ...

  12. Antibiotic tolerance and resistance in biofilms

    DEFF Research Database (Denmark)

    Ciofu, Oana; Tolker-Nielsen, Tim

    2010-01-01

    One of the most important features of microbial biofilms is their tolerance to antimicrobial agents and components of the host immune system. The difficulty of treating biofilm infections with antibiotics is a major clinical problem. Although antibiotics may decrease the number of bacteria...... in biofilms, they will not completely eradicate the bacteria in vivo which may have important clinical consequences in form of relapses of the infection....

  13. Study on Antibiotic compounds from Pseudomonas aeruginosa NO4 Strain

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Ji Young; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2011-05-15

    As important human and veterinary medicines, antibiotics are being produced and consumed in large quantities around the world. For example, more than 50 million pounds (22,000 tons) of antibiotics are produced in the U.S. each year and annual production in Germany is about 2,000 tons. Antibiotics are low molecular weight microbial metabolites that at low concentrations inhibit the growth of other microorganisms. Resistant bacteria may also spread and become broader infection-control problems, not only within health care institutions, but in communities as well. Clinically important bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a common cause of infection among hospitalized patients. Pseudomonas aeruginosa is a major cause of opportunistic infections among immunocompromised individuals. The spread of this organism in health care settings is often difficult to control due to the presence of multiple intrinsic and acquired mechanisms of antimicrobial resistance. In this study, we isolated novel bacterium which had strong antagonistic activity and separated antibiotic compounds from Pseudomonas sp., and analyzed characteristics and molecular weight of the antibiotic compound

  14. Study on Antibiotic compounds from Pseudomonas aeruginosa NO4 Strain

    International Nuclear Information System (INIS)

    Nam, Ji Young; Kim, Jin Kyu

    2011-01-01

    As important human and veterinary medicines, antibiotics are being produced and consumed in large quantities around the world. For example, more than 50 million pounds (22,000 tons) of antibiotics are produced in the U.S. each year and annual production in Germany is about 2,000 tons. Antibiotics are low molecular weight microbial metabolites that at low concentrations inhibit the growth of other microorganisms. Resistant bacteria may also spread and become broader infection-control problems, not only within health care institutions, but in communities as well. Clinically important bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). MRSA is a common cause of infection among hospitalized patients. Pseudomonas aeruginosa is a major cause of opportunistic infections among immunocompromised individuals. The spread of this organism in health care settings is often difficult to control due to the presence of multiple intrinsic and acquired mechanisms of antimicrobial resistance. In this study, we isolated novel bacterium which had strong antagonistic activity and separated antibiotic compounds from Pseudomonas sp., and analyzed characteristics and molecular weight of the antibiotic compound

  15. Genomics of antibiotic-resistance prediction in Pseudomonas aeruginosa.

    Science.gov (United States)

    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.

  16. Antimicrobial properties of Pseudomonas strains producing the antibiotic mupirocin.

    Science.gov (United States)

    Matthijs, Sandra; Vander Wauven, Corinne; Cornu, Bertrand; Ye, Lumeng; Cornelis, Pierre; Thomas, Christopher M; Ongena, Marc

    2014-10-01

    Mupirocin is a polyketide antibiotic with broad antibacterial activity. It was isolated and characterized about 40 years ago from Pseudomonas fluorescens NCIMB 10586. To study the phylogenetic distribution of mupirocin producing strains in the genus Pseudomonas a large collection of Pseudomonas strains of worldwide origin, consisting of 117 Pseudomonas type strains and 461 strains isolated from different biological origins, was screened by PCR for the mmpD gene of the mupirocin gene cluster. Five mmpD(+) strains from different geographic and biological origin were identified. They all produced mupirocin and were strongly antagonistic against Staphylococcus aureus. Phylogenetic analysis showed that mupirocin production is limited to a single species. Inactivation of mupirocin production leads to complete loss of in vitro antagonism against S. aureus, except on certain iron-reduced media where the siderophore pyoverdine is responsible for the in vitro antagonism of a mupirocin-negative mutant. In addition to mupirocin some of the strains produced lipopeptides of the massetolide group. These lipopeptides do not play a role in the observed in vitro antagonism of the mupirocin producing strains against S. aureus. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  17. 40 CFR 180.1145 - Pseudomonas syringae; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Pseudomonas syringae; exemption from... FOOD Exemptions From Tolerances § 180.1145 Pseudomonas syringae; exemption from the requirement of a tolerance. Pseudomonas syringae is exempted from the requirement of a tolerance on all raw agricultural...

  18. 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...

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

    DEFF Research Database (Denmark)

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

    2007-01-01

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

  20. RpoN Modulates Carbapenem Tolerance in Pseudomonas aeruginosa through Pseudomonas Quinolone Signal and PqsE

    Science.gov (United States)

    Murakami, Keiji; Amoh, Takashi; Ono, Tsuneko; Miyake, Yoichiro

    2016-01-01

    The ability of Pseudomonas aeruginosa to rapidly modulate its response to antibiotic stress and persist in the presence of antibiotics is closely associated with the process of cell-to-cell signaling. The alternative sigma factor RpoN (σ54) is involved in the regulation of quorum sensing (QS) and plays an important role in the survival of stationary-phase cells in the presence of carbapenems. Here, we demonstrate that a ΔrpoN mutant grown in nutrient-rich medium has increased expression of pqsA, pqsH, and pqsR throughout growth, resulting in the increased production of the Pseudomonas quinolone signal (PQS). The link between pqsA and its role in carbapenem tolerance was studied using a ΔrpoN ΔpqsA mutant, in which the carbapenem-tolerant phenotype of the ΔrpoN mutant was abolished. In addition, we demonstrate that another mechanism leading to carbapenem tolerance in the ΔrpoN mutant is mediated through pqsE. Exogenously supplied PQS abolished the biapenem-sensitive phenotype of the ΔrpoN ΔpqsA mutant, and overexpression of pqsE failed to alter the susceptibility of the ΔrpoN ΔpqsA mutant to biapenem. The mutations in the ΔrpoN ΔrhlR mutant and the ΔrpoN ΔpqsH mutant led to susceptibility to biapenem. Comparison of the changes in the expression of the genes involved in QS in wild-type PAO1 with their expression in the ΔrpoN mutant and the ΔrpoN mutant-derived strains demonstrated the regulatory effect of RpoN on the transcript levels of rhlR, vqsR, and rpoS. The findings of this study demonstrate that RpoN negatively regulates the expression of PQS in nutrient-rich medium and provide evidence that RpoN interacts with pqsA, pqsE, pqsH, and rhlR in response to antibiotic stress. PMID:27431228

  1. Occurrence of multi-antibiotic resistant Pseudomonas spp. in drinking water produced from karstic hydrosystems.

    Science.gov (United States)

    Flores Ribeiro, Angela; Bodilis, Josselin; Alonso, Lise; Buquet, Sylvaine; Feuilloley, Marc; Dupont, Jean-Paul; Pawlak, Barbara

    2014-08-15

    Aquatic environments could play a role in the spread of antibiotic resistance genes by enabling antibiotic-resistant bacteria transferred through wastewater inputs to connect with autochthonous bacteria. Consequently, drinking water could be a potential pathway to humans and animals for antibiotic resistance genes. The aim of this study was to investigate occurrences of Escherichia coli and Pseudomonas spp. in drinking water produced from a karst, a vulnerable aquifer with frequent increases in water turbidity after rainfall events and run-offs. Water samples were collected throughout the system from the karstic springs to the drinking water tap during three non-turbid periods and two turbid events. E. coli densities in the springs were 10- to 1000-fold higher during the turbid events than during the non-turbid periods, indicating that, with increased turbidity, surface water had entered the karstic system and contaminated the spring water. However, no E. coli were isolated in the drinking water. In contrast, Pseudomonas spp. were isolated from the drinking water only during turbid events, while the densities in the springs were from 10- to 100-fold higher than in the non-turbid periods. All the 580 Pseudomonas spp. isolates obtained from the sampling periods were resistant (to between 1 and 10 antibiotics), with similar resistance patterns. Among all the Pseudomonas isolated throughout the drinking water production system, between 32% and 86% carried the major resistance pattern: ticarcillin, ticarcillin-clavulanic acid, cefsulodin, and/or aztreonam, and/or sulfamethoxazol-trimethoprim, and/or fosfomycin. Finally, 8 Pseudomonas spp. isolates, related to the Pseudomonas putida and Pseudomonas fluorescens species, were isolated from the drinking water. Thus, Pseudomonas could be involved in the dissemination of antibiotic resistance via drinking water during critical periods. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. An update on Pseudomonas aeruginosa biofilm formation, tolerance, and dispersal

    DEFF Research Database (Denmark)

    Harmsen, Morten; Yang, Liang; Pamp, Sünje Johanna

    2010-01-01

    We review the recent advances in the understanding of the Pseudomonas aeruginosa biofilm lifestyle from studies using in vitro laboratory setups such as flow chambers and microtiter trays. Recent work sheds light on the role of nutrients, motility, and quorum sensing in structure formation in P....... aeruginosa biofilms. The second messenger, c-di-GMP, is established as an important regulator of the synthesis of polysaccharide and protein components of the biofilm matrix. Extracellular DNA is shown to be an essential component of the biofilm matrix. It has become apparent that biofilm formation involves...... interactions between different subpopulations. The molecular mechanisms underlying the tolerance of biofilm bacteria to antimicrobial agents are beginning to be unraveled, and new knowledge has been obtained regarding the environmental cues and regulatory mechanisms involved in biofilm dispersal....

  3. Mannitol enhances antibiotic sensitivity of persister bacteria in Pseudomonas aeruginosa biofilms.

    Directory of Open Access Journals (Sweden)

    Nicolas Barraud

    Full Text Available The failure of antibiotic therapies to clear Pseudomonas aeruginosa lung infection, the key mortality factor for cystic fibrosis (CF patients, is partly attributed to the high tolerance of P. aeruginosa biofilms. Mannitol has previously been found to restore aminoglycoside sensitivity in Escherichia coli by generating a proton-motive force (PMF, suggesting a potential new strategy to improve antibiotic therapy and reduce disease progression in CF. Here, we used the commonly prescribed aminoglycoside tobramycin to select for P. aeruginosa persister cells during biofilm growth. Incubation with mannitol (10-40 mM increased tobramycin sensitivity of persister cells up to 1,000-fold. Addition of mannitol to pre-grown biofilms was able to revert the persister phenotype and improve the efficacy of tobramycin. This effect was blocked by the addition of a PMF inhibitor or in a P. aeruginosa mutant strain unable to metabolise mannitol. Addition of glucose and NaCl at high osmolarity also improved the efficacy of tobramycin although to a lesser extent compared to mannitol. Therefore, the primary effect of mannitol in reverting biofilm associated persister cells appears to be an active, physiological response, associated with a minor contribution of osmotic stress. Mannitol was tested against clinically relevant strains, showing that biofilms containing a subpopulation of persister cells are better killed in the presence of mannitol, but a clinical strain with a high resistance to tobramycin was not affected by mannitol. Overall, these results suggest that in addition to improvements in lung function by facilitating mucus clearance in CF, mannitol also affects antibiotic sensitivity in biofilms and does so through an active, physiological response.

  4. Effects of antibiotics on quorum sensing in pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Skindersø, Mette Elena; Alhede, Morten; Phipps, Richard Kerry

    2008-01-01

    in animal infection models. Treatment of cystic fibrosis (CF) patients chronically infected with P. aeruginosa with the macrolide antibiotic azithromycin (AZM) has been demonstrated to improve the clinical outcome. Several studies indicate that AZM may accomplish its beneficial action in CF patients....... Three of the antibiotics tested, AZM, ceftazidime (CFT), and ciprofloxacin (CPR), were very active in the assay and were further examined for their effects on QS-regulated virulence factor production in P. aeruginosa. The effects of the three antibiotics administered at subinhibitory concentrations were...... by impeding QS, thereby reducing the pathogenicity of P. aeruginosa. This led us to investigate whether QS inhibition is a common feature of antibiotics. We present the results of a screening of 12 antibiotics for their QS-inhibitory activities using a previously described QS inhibitor selector 1 strain...

  5. Cell motility and antibiotic tolerance of bacterial swarms

    Science.gov (United States)

    Zuo, Wenlong

    Many bacteria species can move across moist surfaces in a coordinated manner known as swarming. It is reported that swarm cells show higher tolerance to a wide variety of antibiotics than planktonic cells. We used the model bacterium E. coli to study how motility affects the antibiotic tolerance of swarm cells. Our results provide new insights for the control of pathogenic invasion via regulating cell motility. Mailing address: Room 306 Science Centre North Block, The Chinese University of Hong Kong, Shatin, N.T. Hong Kong SAR. Phone: +852-3943-6354. Fax: +852-2603-5204. E-mail: zwlong@live.com.

  6. Nano-antibiotics in chronic lung infection therapy against Pseudomonas aeruginosa.

    Science.gov (United States)

    Hadinoto, Kunn; Cheow, Wean Sin

    2014-04-01

    Antibiotic encapsulation into nanoparticle carriers has emerged as a promising inhaled antibiotic formulation for treatment of chronic Pseudomonas aeruginosa lung infection prevalent in chronic obstructive pulmonary diseases. Attributed to their prolonged lung retention, sustained antibiotic release, and mucus penetrating ability, antibiotic nanoparticles, or nano-antibiotics in short, can address the principal weakness of inhaled antibiotic solution, i.e. low antibiotic exposure in the vicinity of P. aeruginosa biofilm colonies resulting in diminished anti-pseudomonal efficacy after repeated uses. This review details the current state of development and limitations of the two most widely studied forms of nano-antibiotics, i.e. liposomes and polymer nanoparticles. Factors in their formulation that influence the anti-pseudomonal efficacy in vitro and in vivo, such as liposome's membrane rigidity, surface charge, size, and polymer hydrophobicity, are discussed. This review reveals that the superior anti-pseudomonal efficacy of liposomal antibiotics to free antibiotics has been clearly established when they are correctly formulated, with several liposomal antibiotic formulations are currently undergoing clinical trials. Liposomal antibiotics, nevertheless, are not without limitation due to their weak physicochemical stability. In contrast, only mucus penetrating ability of the more stable polymeric nano-antibiotics has been established, while their anti-pseudomonal efficacy has only been examined in vitro from which their superiority to free antibiotics has not been ascertained. Lastly, future research needs to bring liposome and polymer-based nano-antibiotics closer to their clinical realization are identified. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Testosterone 15β-hydroxylation by solvent tolerant Pseudomonas putida S12

    NARCIS (Netherlands)

    Ruijssenaars, H.J.; Sperling, E.M.G.M.; Wiegerinck, P.H.G.; Brands, F.T.L.; Wery, J.; Bont, J.A.M.de

    2007-01-01

    A steroid 15β-hydroxylating whole-cell solvent tolerant biocatalyst was constructed by expressing the Bacillus megaterium steroid hydroxylase CYP106A2 in the solvent tolerant Pseudomonas putida S12. Testosterone hydroxylation was improved by a factor 16 by co-expressing Fer, a putative Fe-S protein

  8. 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....

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

    OpenAIRE

    O. A. Nazarchuk; D. V. Paliy; N. I. Osadchuk

    2017-01-01

    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 fr...

  10. Sublethal Concentrations of Antibiotics Cause Shift to Anaerobic Metabolism in Listeria monocytogenes and Induce Phenotypes Linked to Antibiotic Tolerance

    DEFF Research Database (Denmark)

    Knudsen, Gitte Maegaard; Fromberg, Arvid; Ng, Yin

    2016-01-01

    The human pathogenic bacterium Listeria monocytogenes is exposed to antibiotics both during clinical treatment and in its saprophytic lifestyle. As one of the keys to successful treatment is continued antibiotic sensitivity, the purpose of this study was to determine if exposure to sublethal...... antibiotic concentrations would affect the bacterial physiology and induce antibiotic tolerance. Transcriptomic analyses demonstrated that each of the four antibiotics tested caused an antibiotic-specific gene expression pattern related to mode-of-action of the particular antibiotic. All four antibiotics...... in Imo1179 (eutE) encoding an aldehyde oxidoreductase where rerouting caused increased ethanol production was tolerant to three of four antibiotics tested. This shift in metabolism could be a survival strategy in response to antibiotics to avoid generation of ROS production from respiration by oxidation...

  11. 40 CFR 180.1212 - Pseudomonas chlororaphis Strain 63-28; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Pseudomonas chlororaphis Strain 63-28... RESIDUES IN FOOD Exemptions From Tolerances § 180.1212 Pseudomonas chlororaphis Strain 63-28; exemption... for residues of the microbial pesticide Pseudomonas chlororaphis Strain 63-28 in or on all food...

  12. 40 CFR 180.1200 - Pseudomonas fluorescens strain PRA-25; temporary exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Pseudomonas fluorescens strain PRA-25... RESIDUES IN FOOD Exemptions From Tolerances § 180.1200 Pseudomonas fluorescens strain PRA-25; temporary... established for residues of the microbial pesticide, pseudomonas fluorescens strain PRA-25 when used on peas...

  13. Antibiotic resistance determinants in a Pseudomonas putida strain isolated from a hospital.

    Directory of Open Access Journals (Sweden)

    Lázaro Molina

    Full Text Available Environmental microbes harbor an enormous pool of antibiotic and biocide resistance genes that can impact the resistance profiles of animal and human pathogens via horizontal gene transfer. Pseudomonas putida strains are ubiquitous in soil and water but have been seldom isolated from humans. We have established a collection of P. putida strains isolated from in-patients in different hospitals in France. One of the isolated strains (HB3267 kills insects and is resistant to the majority of the antibiotics used in laboratories and hospitals, including aminoglycosides, ß-lactams, cationic peptides, chromoprotein enediyne antibiotics, dihydrofolate reductase inhibitors, fluoroquinolones and quinolones, glycopeptide antibiotics, macrolides, polyketides and sulfonamides. Similar to other P. putida clinical isolates the strain was sensitive to amikacin. To shed light on the broad pattern of antibiotic resistance, which is rarely found in clinical isolates of this species, the genome of this strain was sequenced and analysed. The study revealed that the determinants of multiple resistance are both chromosomally-borne as well as located on the pPC9 plasmid. Further analysis indicated that pPC9 has recruited antibiotic and biocide resistance genes from environmental microorganisms as well as from opportunistic and true human pathogens. The pPC9 plasmid is not self-transmissible, but can be mobilized by other bacterial plasmids making it capable of spreading antibiotic resistant determinants to new hosts.

  14. 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.

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

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    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.

  16. In vivo Host Environment Alters Pseudomonas aeruginosa Susceptibility to Aminoglycoside Antibiotics

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    Pan, Xiaolei; Dong, Yuanyuan; Fan, Zheng; Liu, Chang; Xia, Bin; Shi, Jing; Bai, Fang; Jin, Yongxin; Cheng, Zhihui; Jin, Shouguang; Wu, Weihui

    2017-01-01

    During host infection, Pseudomonas aeruginosa coordinately regulates the expression of numerous genes to adapt to the host environment while counteracting host clearance mechanisms. As infected patients take antibiotics, the invading bacteria encounter antibiotics in the host milieu. P. aeruginosa is highly resistant to antibiotics due to multiple chromosomally encoded resistant determinants. And numerous in vitro studies have demonstrated the regulatory mechanisms of antibiotic resistance related genes in response to antibiotics. However, it is not well-known how host environment affects bacterial response to antibiotics. In this study, we found that P. aeruginosa cells directly isolated from mice lungs displayed higher susceptibility to tobramycin than in vitro cultured bacteria. In vitro experiments demonstrated that incubation with A549 and differentiated HL60 (dHL60) cells sensitized P. aeruginosa to tobramycin. Further studies revealed that reactive oxygen species produced by the host cells contributed to the increased bacterial susceptibility. At the same concentration of tobramycin, presence of A549 and dHL60 cells resulted in higher expression of heat shock proteins, which are known inducible by tobramycin. Further analyses revealed decreased membrane potential upon incubation with the host cells and modification of lipopolysaccharide, which contributed to the increased susceptibility to tobramycin. Therefore, our results demonstrate that contact with host cells increased bacterial susceptibility to tobramycin. PMID:28352614

  17. Successful treatment of Pseudomonas aeruginosa osteomyelitis with antibiotic monotherapy of limited duration.

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    Laghmouche, Nadir; Compain, Fabrice; Jannot, Anne-Sophie; Guigui, Pierre; Mainardi, Jean-Luc; Lonjon, Guillaume; Bouyer, Benjamin; Fernandez-Gerlinger, Marie-Paule

    2017-09-01

    The aim of this study was to present a 15-year experience and provide a comprehensive analysis of a large cohort of patients with Pseudomonas aeruginosa osteomyelitis. We reviewed the medical records of patients admitted to a large French university hospital for P. aeruginosa osteomyelitis over a 15-year period. Patient outcome was assessed at follow-up after at least six months. Sixty-seven patients were included, comprising 57% with chronic osteomyelitis. Polymicrobial infection was predominant (63%), and an infected device was involved in 39% patients. The overall treatment success rate was 79.1%. All but one patient were treated with a combination of surgery and antibiotic therapy. The antibiotic treatment had a mean duration of 45 days (range, 21-90 days). Single-antibiotic therapy was preferred in nearly all cases. Treatment failure was reported for 14 (21%) patients and was due to the persistence of P. aeruginosa in four cases. No significant risk factor for treatment failure was identified, especially when treatment strategies were compared. We advocate optimal surgical debridement combined with initial parenteral antibiotics for a maximum of 15 days, followed by an oral fluoroquinolone. Total treatment duration should not exceed six weeks, and antibiotic treatment with two-drug combinations does not seem necessary. Copyright © 2017 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  18. 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.

  19. Relationship between cystic fibrosis respiratory tract bacterial communities and age, genotype, antibiotics and Pseudomonas aeruginosa.

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    Klepac-Ceraj, Vanja; Lemon, Katherine P; Martin, Thomas R; Allgaier, Martin; Kembel, Steven W; Knapp, Alixandra A; Lory, Stephen; Brodie, Eoin L; Lynch, Susan V; Bohannan, Brendan J M; Green, Jessica L; Maurer, Brian A; Kolter, Roberto

    2010-05-01

    Polymicrobial bronchopulmonary infections in cystic fibrosis (CF) cause progressive lung damage and death. Although the arrival of Pseudomonas aeruginosa often heralds a more rapid rate of pulmonary decline, there is significant inter-individual variation in the rate of decline, the causes of which remain poorly understood. By coupling culture-independent methods with ecological analyses, we discovered correlations between bacterial community profiles and clinical disease markers in respiratory tracts of 45 children with CF. Bacterial community complexity was inversely correlated with patient age, presence of P. aeruginosa and antibiotic exposure, and was related to CF genotype. Strikingly, bacterial communities lacking P. aeruginosa were much more similar to each other than were those containing P. aeruginosa, regardless of antibiotic exposure. This suggests that community composition might be a better predictor of disease progression than the presence of P. aeruginosa alone and deserves further study.

  20. Pseudomonas aeruginosa Bacteremia among Immunocompetent and Immunocompromised Patients: Relation to Initial Antibiotic Therapy and Survival.

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    Migiyama, Yohei; Yanagihara, Katsunori; Kaku, Norihito; Harada, Yosuke; Yamada, Koichi; Nagaoka, Kentaro; Morinaga, Yoshitomo; Akamatsu, Norihiko; Matsuda, Junichi; Izumikawa, Koichi; Kohrogi, Hirotsugu; Kohno, Shigeru

    2016-01-01

    Pseudomonas aeruginosa bacteremia occurs mainly in immunocompromised patients. However, P. aeruginosa bacteremia in immunocompetent patients has also been reported. The aim of this study was to evaluate the clinical characteristics of P. aeruginosa bacteremia in relation to the immune status of the patients. The medical records of 126 adult patients with P. aeruginosa bacteremia in Nagasaki University Hospital were retrospectively reviewed between January 2003 and December 2012. Of 126 patients with P. aeruginosa bacteremia, 60 patients (47.6%) were classified as immunocompetent. Mortality in immunocompetent patients tended to be lower than in immunocompromised patients (7-day mortality, 8% vs. 30%, P antibiotic therapy (HR: 0.21, P immunocompromised, but not immunocompetent patients, initial appropriate antibiotic therapy was associated with lower mortality (30-day mortality 20.5% vs. 66.7%, P < 0.01 by log-rank test).

  1. No apparent costs for facultative antibiotic production by the soil bacterium Pseudomonas fluorescens Pf0-1.

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    Garbeva, Paolina; Tyc, Olaf; Remus-Emsermann, Mitja N P; van der Wal, Annemieke; Vos, Michiel; Silby, Mark; de Boer, Wietse

    2011-01-01

    Many soil-inhabiting bacteria are known to produce secondary metabolites that can suppress microorganisms competing for the same resources. The production of antimicrobial compounds is expected to incur fitness costs for the producing bacteria. Such costs form the basis for models on the co-existence of antibiotic-producing and non-antibiotic producing strains. However, so far studies quantifying the costs of antibiotic production by bacteria are scarce. The current study reports on possible costs, for antibiotic production by Pseudomonas fluorescens Pf0-1, a soil bacterium that is induced to produce a broad-spectrum antibiotic when it is confronted with non-related bacterial competitors or supernatants of their cultures. We measured the possible cost of antibiotic production for Pseudomonas fluorescens Pf0-1 by monitoring changes in growth rate with and without induction of antibiotic production by supernatant of a bacterial competitor, namely Pedobacter sp.. Experiments were performed in liquid as well as on semi-solid media under nutrient-limited conditions that are expected to most clearly reveal fitness costs. Our results did not reveal any significant costs for production of antibiotics by Pseudomonas fluorescens Pf0-1. Comparison of growth rates of the antibiotic-producing wild-type cells with those of non-antibiotic producing mutants did not reveal costs of antibiotic production either. Based on our findings we propose that the facultative production of antibiotics might not be selected to mitigate metabolic costs, but instead might be advantageous because it limits the risk of competitors evolving resistance, or even the risk of competitors feeding on the compounds produced.

  2. No apparent costs for facultative antibiotic production by the soil bacterium Pseudomonas fluorescens Pf0-1.

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    Paolina Garbeva

    Full Text Available BACKGROUND: Many soil-inhabiting bacteria are known to produce secondary metabolites that can suppress microorganisms competing for the same resources. The production of antimicrobial compounds is expected to incur fitness costs for the producing bacteria. Such costs form the basis for models on the co-existence of antibiotic-producing and non-antibiotic producing strains. However, so far studies quantifying the costs of antibiotic production by bacteria are scarce. The current study reports on possible costs, for antibiotic production by Pseudomonas fluorescens Pf0-1, a soil bacterium that is induced to produce a broad-spectrum antibiotic when it is confronted with non-related bacterial competitors or supernatants of their cultures. METHODOLOGY AND PRINCIPAL FINDINGS: We measured the possible cost of antibiotic production for Pseudomonas fluorescens Pf0-1 by monitoring changes in growth rate with and without induction of antibiotic production by supernatant of a bacterial competitor, namely Pedobacter sp.. Experiments were performed in liquid as well as on semi-solid media under nutrient-limited conditions that are expected to most clearly reveal fitness costs. Our results did not reveal any significant costs for production of antibiotics by Pseudomonas fluorescens Pf0-1. Comparison of growth rates of the antibiotic-producing wild-type cells with those of non-antibiotic producing mutants did not reveal costs of antibiotic production either. SIGNIFICANCE: Based on our findings we propose that the facultative production of antibiotics might not be selected to mitigate metabolic costs, but instead might be advantageous because it limits the risk of competitors evolving resistance, or even the risk of competitors feeding on the compounds produced.

  3. Improvement in solvent tolerance by exogenous glycerol in Pseudomonas sp. BCNU 106.

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    Choi, H J; Lim, B R; Park, Y J; Joo, W H

    2017-08-01

    Solvent hypertolerant Pseudomonas sp. BCNU 106 still has some underlying growth limitation in solvents. Therefore, efficient mass cultivation methods are needed to pursue its applications in biotechnology. Pseudomonas sp. BCNU 106 was cultured in a medium supplemented with 0·05 mol l -1 glycerol and cell survival was monitored during its cultivation in the presence of 1% (v/v) toluene. Exogenously supplemented glycerol provided more protection against damage caused by toluene stress and conferred higher solvent tolerance of Pseudomonas sp. BCNU 106 to toluene compared to control Pseudomonas sp. BCNU 106 without the supplementation of glycerol. This low-cost mass cultivation method can be used to efficiently apply solvent-tolerant bacteria in biotransformation and biodegradation. Protection against toluene and improvement in bacterial cell growth by supplementation of glycerol in the presence of toluene are demonstrated in this study. This result can be used to solve growth-related hindrances of solvent-tolerant bacteria and establish their low-cost mass cultivation, thereby broadening their industrial and environmental applications. © 2017 The Society for Applied Microbiology.

  4. [Analysis of resistant genes of beta-lactam antibiotics from Pseudomonas aeruginosa in pediatric patients].

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    Dong, Fang; Xu, Xi-wei; Song, Wen-qi; Lü, Ping; Yang, Yong-hong; Shen, Xu-zhuang

    2008-11-18

    To analyze the antibiotic resistance of the Pseudomonas aeruginosa (PA) isolated from pediatric patients and the resistant genes of beta-lactam antibiotics thereof. 146 PA strains were isolated from pediatric patients. Agar dilution method recommended by the Clinical and Laboratory Standards Institute was used to examine the minimum inhibitory concentrations (MICs) of 12 antimicrobial agents, including the penicillins, third and fourth genet ration cephalosporins, carbapenemase, Aztreonam, beta-lactamase inhibitors, quinolones, and aminoglycosides. PCR was used to detect the expression of the genes TEM, SHV, OXA, PER, GES, CTX-M, IMP, VIM, DHA, MIR, FOX, and oprD2. The multi-drug resistance rates against different antibiotic were high among the 146 PA strains. The rates of imipenem and meropenem resistance were 41.1% and 35.6% respectively. Among the 146 PA strains, 46 (31.5%) were positive for the MBL genotype; 38 (82.6%) carried the blaIMP gene, 8 (17.4%) carried the blaVIM gene, and 114 (78.1%) were oprD2 negative. The genes TEM, SHV, OXA, CTX-M, PER, VEB, GES, FOX, MIR, and DHA were not found in all strains. Many PA isolated from pediatric patients carry the genes IMP or VIM and losses oprD2 gene related to the expression of the outer membrane porin OprD2. The loss of the gene oprD2 is essential mechanism of beta-lactam antibiotics resistance in PA.

  5. Cyclic lipodepsipeptides produced by Pseudomonas spp. naturally present in raw milk induce inhibitory effects on microbiological inhibitor assays for antibiotic residue screening.

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    Wim Reybroeck

    Full Text Available Two Pseudomonas strains, identified as closely related to Pseudomonas tolaasii, were isolated from milk of a farm with frequent false-positive Delvotest results for screening putative antibiotic residues in raw milk executed as part of the regulatory quality programme. Growth at 5 to 7°C of these isolates in milk resulted in high lipolysis and the production of bacterial inhibitors. The two main bacterial inhibitors have a molecular weight of 1168.7 and 1140.7 Da respectively, are heat-tolerant and inhibit Geobacillus stearothermophilus var. calidolactis, the test strain of most of the commercially available microbiological inhibitor tests for screening of antibiotic residues in milk. Furthermore, these bacterial inhibitors show antimicrobial activity against Staphylococcus aureus, Bacillus cereus and B. subtilis and also interfere negatively with yoghurt production. Following their isolation and purification with RP-HPLC, the inhibitors were identified by NMR analysis as cyclic lipodepsipeptides of the viscosin group. Our findings bring to light a new challenge for quality control in the dairy industry. By prolonging the refrigerated storage of raw milk, the keeping quality of milk is influenced by growth and metabolic activities of psychrotrophic bacteria such as pseudomonads. Besides an increased risk of possible spoilage of long shelf-life milk, the production at low temperature of natural bacterial inhibitors may also result in false-positive results for antibiotic residue screening tests based on microbial inhibitor assays thus leading to undue production loss.

  6. Antibiotic resistance profile of Pseudomonas aeruginosa isolated from aquaculture and abattoir environments in urban communities

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    Isoken Henrietta Igbinosa

    2017-01-01

    Full Text Available Objective: To characterize multiple antibiotic resistance profile of Pseudomonas aeruginosa from aquaculture and abattoir environments. Methods: Wastewater samples were obtained from the abattoir and aquaculture environments between May 2016 and July 2016 and analysed using standard phenotypic, biochemical and PCR-based methods. Results: The mean pseudomonads count ranged from (4 × 102 ± 1.01 to (2 × 104 ± 0.10 colony-forming unit/mL in the aquaculture environment and (3 × 103 ± 0.00 to (1 × 105 ± 1.00 colony-forming unit/mL in the abattoir environment. A total of 96 isolates of Pseudomonas aeruginosa confirmed by PCR were thereafter selected from both aquaculture and abattoir environments and further characterized for their antimicrobial susceptibility profile by adopting the disc diffusion method. High level of resistance was observed against the aminoglycosides [gentamycin 64/96 (66.67% and kanamycin 52/96 (54.17%], monobactams [aztreonam 76/96 (79.17%], carbapenems [meropenem 52/96 (54.17%], tetracyclines [tetracycline 72/96 (75.00%] and cephems [ceftazidime 72/96 (75.00% and cefuroxime 48/96 (50.00%]. Multiple antibiotic resistant index of the respective isolates ranged from 0.4 to 0.8 while multidrug resistant profile of the isolates revealed that 28 of the respective isolates were resistant to ceftazidime, cefuroxime, gentamycin, kanamycin, aztreonam which belongs to cephems, aminoglycosides and monobactam class of antimicrobials. Conclusions: Findings from the present study therefore underscores the need for effective monitoring of the abattoir and aquaculture environments as they could be the significant source for spreading antibiotic resistant bacteria within the environment.

  7. Novel AroA from Pseudomonas putida Confers Tobacco Plant with High Tolerance to Glyphosate

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    Yan, Hai-Qin; Chang, Su-Hua; Tian, Zhe-Xian; Zhang, Le; Sun, Yi-Cheng; Li, Yan; Wang, Jing; Wang, Yi-Ping

    2011-01-01

    Glyphosate is a non-selective broad-spectrum herbicide that inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS, also designated as AroA), a key enzyme in the aromatic amino acid biosynthesis pathway in microorganisms and plants. Previously, we reported that a novel AroA (PpAroA1) from Pseudomonas putida had high tolerance to glyphosate, with little homology to class I or class II glyphosate-tolerant AroA. In this study, the coding sequence of PpAroA1 was optimized for tobacco. For maturation of the enzyme in chloroplast, a chloroplast transit peptide coding sequence was fused in frame with the optimized aroA gene (PparoA1optimized) at the 5′ end. The PparoA1optimized gene was introduced into the tobacco (Nicotiana tabacum L. cv. W38) genome via Agrobacterium-mediated transformation. The transformed explants were first screened in shoot induction medium containing kanamycin. Then glyphosate tolerance was assayed in putative transgenic plants and its T1 progeny. Our results show that the PpAroA1 from Pseudomonas putida can efficiently confer tobacco plants with high glyphosate tolerance. Transgenic tobacco overexpressing the PparoA1optimized gene exhibit high tolerance to glyphosate, which suggest that the novel PpAroA1 is a new and good candidate applied in transgenic crops with glyphosate tolerance in future. PMID:21611121

  8. Synergistic Interaction Between Phage Therapy and Antibiotics Clears Pseudomonas Aeruginosa Infection in Endocarditis and Reduces Virulence.

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    Oechslin, Frank; Piccardi, Philippe; Mancini, Stefano; Gabard, Jérôme; Moreillon, Philippe; Entenza, José M; Resch, Gregory; Que, Yok-Ai

    2017-03-01

    Increasing antibiotic resistance warrants therapeutic alternatives. Here we investigated the efficacy of bacteriophage-therapy (phage) alone or combined with antibiotics against experimental endocarditis (EE) due to Pseudomonas aeruginosa, an archetype of difficult-to-treat infection. In vitro fibrin clots and rats with aortic EE were treated with an antipseudomonas phage cocktail alone or combined with ciprofloxacin. Phage pharmacology, therapeutic efficacy, and resistance were determined. In vitro, single-dose phage therapy killed 7 log colony-forming units (CFUs)/g of fibrin clots in 6 hours. Phage-resistant mutants regrew after 24 hours but were prevented by combination with ciprofloxacin (2.5 × minimum inhibitory concentration). In vivo, single-dose phage therapy killed 2.5 log CFUs/g of vegetations in 6 hours (P 6 log CFUs/g of vegetations in 6 hours and successfully treating 64% (n = 7/11) of rats. Phage-resistant mutants emerged in vitro but not in vivo, most likely because resistant mutations affected bacterial surface determinants important for infectivity (eg, the pilT and galU genes involved in pilus motility and LPS formation). Single-dose phage therapy was active against P. aeruginosa EE and highly synergistic with ciprofloxacin. Phage-resistant mutants had impaired infectivity. Phage-therapy alone or combined with antibiotics merits further clinical consideration. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

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

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

    2014-12-10

    The growth of bacteria as structured aggregates termed biofilms leads to their protection from harsh environmental conditions such as physical and chemical stresses, shearing forces, and limited nutrient availability. Because of this highly adapted ability to survive adverse environmental conditions, bacterial biofilms are recalcitrant to antibiotic therapies and immune clearance. This is particularly problematic in hospital settings where biofilms are a frequent cause of chronic and device-related infections and constitute a significant burden on the health-care system. The major therapeutic strategy against infections is the use of antibiotics, which, due to adaptive resistance, are often insufficient to clear biofilm infections. Thus, novel biofilm-specific therapies are required. Specific features of biofilm development, such as surface adherence, extracellular matrix formation, quorum sensing, and highly regulated biofilm maturation and dispersal are currently being studied as targets to be exploited in the development of novel biofilm-specific treatments. Using Pseudomonas aeruginosa for illustrative purposes, this review highlights the antibiotic resistance mechanisms of biofilms, and discusses current research into novel biofilm-specific therapies. Copyright © 2014 Elsevier B.V. All rights reserved.

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

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

    2013-08-01

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

  11. Effectiveness of halo-tolerant, auxin producing Pseudomonas and Rhizobium strains to improve osmotic stress tolerance in mung bean (Vigna radiata L.

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    Maqshoof Ahmad

    2013-12-01

    Full Text Available Halo-tolerant, auxin producing bacteria could be used to induce salt tolerance in plants. A number of Rhizobium and auxin producing rhizobacterial strains were assessed for their ability to tolerate salt stress by conducting osmoadaptation assay. The selected strains were further screened for their ability to induce osmotic stress tolerance in mung bean seedlings under salt-stressed axenic conditions in growth pouch/jar trials. Three most effective strains of Rhizobium and Pseudomonas containing ACC-deaminase were evaluated in combination, for their ability to induce osmotic stress tolerance in mung bean at original, 4, and 6 dS m-1 under axenic conditions. Results showed that sole inoculation of Rhizobium and Pseudomonas strains improved the total dry matter up to 1.4, and 1.9 fold, respectively, while the increase in salt tolerance index was improved up to 1.3 and 2.0 fold by the Rhizobium and Pseudomonas strains, respectively. However, up to 2.2 fold increase in total dry matter and salt tolerance index was observed due to combined inoculation of Rhizobium and Pseudomonas strains. So, combined application of Rhizobium and Pseudomonas strains could be explored as an effective strategy to induce osmotic stress tolerance in mung bean.

  12. Association of metal tolerance with multiple antibiotic resistance of bacteria isolated from drinking water.

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    Calomiris, J J; Armstrong, J L; Seidler, R J

    1984-06-01

    Bacterial isolates from the drinking water system of an Oregon coastal community were examined to assess the association of metal tolerance with multiple antibiotic resistance. Positive correlations between tolerance to high levels of Cu2+, Pb2+, and Zn2+ and multiple antibiotic resistance were noted among bacteria from distribution waters but not among bacteria from raw waters. Tolerances to higher levels of Al3+ and Sn2+ were demonstrated more often by raw water isolates which were not typically multiple antibiotic resistant. A similar incidence of tolerance to Cd2+ was demonstrated by isolates of both water types and was not associated with multiple antibiotic resistance. These results suggest that simultaneous selection phenomena occurred in distribution water for bacteria which exhibited unique patterns of tolerance to Cu2+, Pb2+, and Zn2+ and antibiotic resistance.

  13. Antibiotic-resistant Pseudomonas aeruginosa infection in patients with bronchiectasis: prevalence, risk factors and prognostic implications

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    Gao YH

    2018-01-01

    Full Text Available Yong-hua Gao,1,* Wei-jie Guan,2,* Ya-nan Zhu,3 Rong-chang Chen,2 Guo-jun Zhang1 1Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 2State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 3Department of Emergency Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, People’s Republic of China *These authors contributed equally to this work Background and aims: Pseudomonas aeruginosa (PA is the most common pathogen in bronchiectasis and frequently develops resistance to multiple classes of antibiotics, but little is known about the clinical impacts of PA-resistant (PA-R isolates on bronchiectasis. We, therefore, investigated the prevalence, risk factors and prognostic implications of PA-R isolates in hospitalized bronchiectasis patients.Patients and methods: Between June 2011 and July 2016, data from adult bronchiectasis patients isolated with PA at the First Affiliated Hospital of Zhengzhou University were retrospectively analyzed. PA was classified as PA-R in case antibiogram demonstrated resistance on at least one occasion.Results: Seven hundred forty-seven bronchiectasis patients were assessed. Of these, 147 (19.7% had PA isolate in the sputum or bronchoscopic culture. PA-R and PA-sensitive accounted for 88 (59.9% and 59 (31.1% patients, respectively. In multivariate model, factors associated with PA-R isolate in bronchiectasis included prior exposure to antibiotics (odds ratio [OR] =6.18, three or more exacerbations in the previous year (OR =2.81, higher modified Medical Research Council dyspnea scores (OR =1.93 and greater radiologic severity (OR =1.15. During follow-up (median: 26 months; interquartile range: 6–59 months, 36 patients died, of whom 24 (66

  14. Tracking down antibiotic-resistant Pseudomonas aeruginosa isolates in a wastewater network.

    Directory of Open Access Journals (Sweden)

    Céline Slekovec

    Full Text Available The Pseudomonas aeruginosa-containing wastewater released by hospitals is treated by wastewater treatment plants (WWTPs, generating sludge, which is used as a fertilizer, and effluent, which is discharged into rivers. We evaluated the risk of dissemination of antibiotic-resistant P. aeruginosa (AR-PA from the hospital to the environment via the wastewater network. Over a 10-week period, we sampled weekly 11 points (hospital and urban wastewater, untreated and treated water, sludge of the wastewater network and the river upstream and downstream of the WWTP of a city in eastern France. We quantified the P. aeruginosa load by colony counting. We determined the susceptibility to 16 antibiotics of 225 isolates, which we sorted into three categories (wild-type, antibiotic-resistant and multidrug-resistant. Extended-spectrum β-lactamases (ESBLs and metallo-β-lactamases (MBLs were identified by gene sequencing. All non-wild-type isolates (n = 56 and a similar number of wild-type isolates (n = 54 were genotyped by pulsed-field gel electrophoresis and multilocus sequence typing. Almost all the samples (105/110, 95.5% contained P. aeruginosa, with high loads in hospital wastewater and sludge (≥3×10(6 CFU/l or/kg. Most of the multidrug-resistant isolates belonged to ST235, CC111 and ST395. They were found in hospital wastewater and some produced ESBLs such as PER-1 and MBLs such as IMP-29. The WWTP greatly reduced P. aeruginosa counts in effluent, but the P. aeruginosa load in the river was nonetheless higher downstream than upstream from the WWTP. We conclude that the antibiotic-resistant P. aeruginosa released by hospitals is found in the water downstream from the WWTP and in sludge, constituting a potential risk of environmental contamination.

  15. PFGE and antibiotic susceptibility phenotype analysis of Pseudomonas aeruginosa strain chronically infecting Cystic Fibrosis patients

    Directory of Open Access Journals (Sweden)

    Giovanna Pulcrano

    2008-09-01

    Full Text Available Pseudomonas aeruginosa is the leading cause of chronic lung infection and following pulmonary worsening of cystic fibrosis patients. To verify whether bacterial modifications regarding motility, mucoidy, and serum susceptibility proceeded from an adaptation to chronic infection or a replacement with a new strain, sequential P. aeruginosa isolates of known phenotype collected from 5 cystic fibrosis patients were typed by pulsed-field gel electophoresis (PFGE. Antimicrobial susceptibility testing of all isolates was performed by the disc diffusion method. PFGE typing demonstrated that strains dissimilar in colony morphotype and of different antibiotic susceptibility patterns could be of the same genotype. Some patients were colonized with a rather constant P. aeruginosa flora, with strains of different phenotypes but of one genotype. Instead, some patients may be colonized by more than one genotype. Secretion of mucoid exopolysaccharide and acquisition of a new antibiotic susceptibility phenotype in these strain appear to evolve during chronic colonization in cystic fibrosis patients from specific adaptation to infection rather than from acquisition of new bacterial strains.

  16. Correlation between phenotypic antibiotic susceptibility and the resistome in Pseudomonas aeruginosa.

    Science.gov (United States)

    Jaillard, Magali; van Belkum, Alex; Cady, Kyle C; Creely, David; Shortridge, Dee; Blanc, Bernadette; Barbu, E Magda; Dunne, W Michael; Zambardi, Gilles; Enright, Mark; Mugnier, Nathalie; Le Priol, Christophe; Schicklin, Stéphane; Guigon, Ghislaine; Veyrieras, Jean-Baptiste

    2017-08-01

    Genetic determinants of antibiotic resistance (AR) have been extensively investigated. High-throughput sequencing allows for the assessment of the relationship between genotype and phenotype. A panel of 672 Pseudomonas aeruginosa strains was analysed, including representatives of globally disseminated multidrug-resistant and extensively drug-resistant clones; genomes and multiple antibiograms were available. This panel was annotated for AR gene presence and polymorphism, defining a resistome in which integrons were included. Integrons were present in >70 distinct cassettes, with In5 being the most prevalent. Some cassettes closely associated with clonal complexes, whereas others spread across the phylogenetic diversity, highlighting the importance of horizontal transfer. A resistome-wide association study (RWAS) was performed for clinically relevant antibiotics by correlating the variability in minimum inhibitory concentration (MIC) values with resistome data. Resistome annotation identified 147 loci associated with AR. These loci consisted mainly of acquired genomic elements and intrinsic genes. The RWAS allowed for correct identification of resistance mechanisms for meropenem, amikacin, levofloxacin and cefepime, and added 46 novel mutations. Among these, 29 were variants of the oprD gene associated with variation in meropenem MIC. Using genomic and MIC data, phenotypic AR was successfully correlated with molecular determinants at the whole-genome sequence level. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  17. Antibiotic and biosurfactant properties of cyclic lipopeptides produced by fluorescent Pseudomonas spp. from the sugar beet rhizosphere

    DEFF Research Database (Denmark)

    Nielsen, T H; Sørensen, D; Tobiasen, C

    2002-01-01

    Cyclic lipopeptides (CLPs) with antibiotic and biosurfactant properties are produced by a number of soil bacteria, including fluorescent Pseudomonas spp. To provide new and efficient strains for the biological control of root-pathogenic fungi in agricultural crops, we isolated approximately 600...... in the peptide moiety. Production of specific CLPs could be affiliated with Pseudomonas fluorescens strain groups belonging to biotype I, V, or VI. In vitro analysis using both purified CLPs and whole-cell P. fluorescens preparations demonstrated that all CLPs exhibited strong biosurfactant properties...

  18. Antibiotic tolerance and the alternative lifestyles of Staphylococcus aureus.

    Science.gov (United States)

    Bui, Long M G; Conlon, Brian P; Kidd, Stephen P

    2017-02-28

    Staphylococcus aureus has an incredible ability to survive, either by adapting to environmental conditions or defending against exogenous stress. Although there are certainly important genetic traits, in part this ability is provided by the breadth of modes of growth S. aureus can adopt. It has been proposed that while within their host, S. aureus survives host-generated and therapeutic antimicrobial stress via alternative lifestyles: a persister sub-population, through biofilm growth on host tissue or by growing as small colony variants (SCVs). Key to an understanding of chronic and relapsing S. aureus infections is determining the molecular basis for its switch to these quasi-dormant lifestyles. In a multicellular biofilm, the metabolically quiescent bacterial community additionally produces a highly protective extracellular polymeric substance (EPS). Furthermore, there are bacteria within a biofilm community that have an altered physiology potentially equivalent to persister cells. Recent studies have directly linked the cellular ATP production by persister cells as their key feature and the basis for their tolerance of a range of antibiotics. In clinical settings, SCVs of S. aureus have been observed for many years; when cultured, these cells form non-pigmented colonies and are approximately ten times smaller than their counterparts. Various genotypic factors have been identified in attempts to characterize S. aureus SCVs and different environmental stresses have been implicated as important inducers. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  19. Detection of Tox A Gene in Pseudomonas aeruginosa Strains Isolated from Dairy Products Using PCR and Determining the Antibiotic Resistance Pattern

    Directory of Open Access Journals (Sweden)

    Faeze Zadsafar

    2017-08-01

    Conclusion: Due to high presence of Pseudomonas aeruginosa in raw milk and existence of antibiotic resistance genes in this bacterium, applying appropriate strategies for hygiene control in animal husbandries, is necessary to prevent the spread of bacteria.

  20. Antibiotic and biosurfactant properties of cyclic lipopeptides produced by fluorescent Pseudomonas spp. from the sugar beet rhizosphere

    DEFF Research Database (Denmark)

    Nielsen, T.H.; Sørensen, D.; Tobiasen, C.

    2002-01-01

    Cyclic lipopeptides (CLPs) with antibiotic and biosurfactant properties are produced by a number of soil bacteria, including fluorescent Pseudomonas spp. To provide new and efficient strains for the biological control of root-pathogenic fungi in agricultural crops, we isolated approximately 600...... fluorescent Pseudomonas spp. from two different agricultural soils by using three different growth media. CLP production was observed in a large proportion of the strains (approximately 60%) inhabiting the sandy soil, compared to a low proportion (approximately 6%) in the loamy soil. Chemical structure...... in the peptide moiety. Production of specific CLPs could be affiliated with Pseudomonas fluorescens strain groups belonging to biotype I, V, or VI. In vitro analysis using both purified CLPs and whole-cell P. fluorescens preparations demonstrated that all CLPs exhibited strong biosurfactant properties...

  1. SENSITIVITY TO ANTIBIOTICS, ANTISEPTICAL NOSOCOMIAL PSEUDOMONAS AERUGINOSA, ISOLATED IN UROLOGICAL PATIENTS

    Directory of Open Access Journals (Sweden)

    Rymsha E.V.

    2015-05-01

    g∕ ml For chlorhexidine MBsC 125 ± 8,88 μg∕ ml. Conclusion. Resistance nosocomial strains of P. aeruginosa at the present time is a serious clinical problem. Of all the antibiotics, the lowest level of resistance was determined to Meropenem. Antibacterial drugs, active against P. aeruginosa - Meropenem > amikacin > ceftazidime > imipenem > ciprofloxacin > piperacillin/tazobactam > piperacillin > gentamicin. Found that antibiotic-resistant strains of the Pseudomonas had a low level of sensitivity to antiseptics.

  2. Auto Poisoning of the Respiratory Chain by a Quorum Sensing Regulated Molecule Favors Biofilm Formation and Antibiotic Tolerance

    Science.gov (United States)

    Hazan, Ronen; Que, Yok Ai; Maura, Damien; Strobel, Benjamin; Majcherczyk, Paul Anthony; Hopper, Laura Rose; Wilbur, David J.; Hreha, Teri N.; Barquera, Blanca; Rahme, Laurence G.

    2015-01-01

    Summary Bacterial programmed cell death and quorum sensing are direct examples of prokaryote group behaviors, wherein cells coordinate their actions to function cooperatively like one organism for the benefit of the whole culture. We demonstrate here that 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO), a Pseudomonas aeruginosa quorum sensing -regulated low-molecular-weight excreted molecule, and triggers autolysis by self-perturbing the electron transfer reactions of the cytochrome bc1 complex. HQNO induces specific self-poisoning by disrupting the flow of electrons through the respiratory chain at the cytochrome bc1 complex, causing a leak of reducing equivalents to O2 whereby electrons that would normally be passed to cytochrome c are donated directly to O2. The subsequent mass production of reactive oxygen species (ROS) reduces membrane potential and disrupts membrane integrity, causing bacterial cell autolysis and DNA release. DNA subsequently promotes biofilm formation and increases antibiotic tolerance to beta-lactams, suggesting that HQNO-dependent cell autolysis is advantageous to the bacterial populations. These data both identify a new programmed cell death system, and a novel role for HQNO as a critical-inducer of biofilm formation and antibiotic tolerance. This newly identified pathway suggests intriguing mechanistic similarities with the initial mitochondrial-mediated steps of eukaryotic apoptosis. PMID:26776731

  3. The Survey of Withani somnifera Extraction against Resistant Strains of Pseudomonas aeruginosa Bacteria to Selective Antibiotics

    Directory of Open Access Journals (Sweden)

    Mohammad Bokaeian

    2015-11-01

    Full Text Available Introduction:  Due  to  more  resistance  of  pathogenic  bacteria  to  new  and  current antibiotics  researchers  are  looking  to  find  the  agents  of  herbal  with  antimicrobial activities in order to replace chemical drugs.Methods:   The herbal extract of Withani somnifera was done by using a rotary vacuum,20 strains of Pseudomons aeruginosa were isolated from urinary infections hospitalized patients  in  city of Zabol  hospital.  The  MIC  Withani  somnifera  were  determined  by dilution method in various concentrations. Sensitivity of strains to multiple antibiotics was evaluated by standard disk diffusion Kirby-Bauer.Results:    The  result  showed  that  P.  aeruginosa  were  resistance  to  4  of the  agents including ampicillin  (85%, nitrofurantoin  (65%, nalidixic acid  (65%, ciprofloxacin (15% and for 5 strains of Pseudomonas showed MIC with activity of 100 ppm.Conclusion:   This  study  has  suggested  the  effect  of  winter  cherry  extract  on  P. aeruginosa in the in vitro assay. It s effectiveness of on in vivo system can be examined in future.

  4. New insights about antibiotic production by Pseudomonas aeruginosa: a gene expression analysis

    Science.gov (United States)

    Gionco, Bárbara; Tavares, Eliandro R.; de Oliveira, Admilton G.; Yamada-Ogatta, Sueli F.; do Carmo, Anderson O.; Pereira, Ulisses de Pádua; Chideroli, Roberta T.; Simionato, Ane S.; Navarro, Miguel O. P.; Chryssafidis, Andreas L.; Andrade, Galdino

    2017-09-01

    The bacterial resistance for antibiotics is one of the most important problems in public health and only a small number of new products are in development. Antagonistic microorganisms from soil are a promising source of new candidate molecules. Products of secondary metabolism confer adaptive advantages for their producer, in the competition for nutrients in the microbial community. The biosynthesis process of compounds with antibiotic activity is the key to optimize their production and the transcriptomic study of microorganisms is of great benefit for the discovery of these metabolic pathways. Pseudomonas aeruginosa LV strain growing in the presence of copper chloride produces a bioactive organometallic compound, which has a potent antimicrobial activity against various microorganisms. The objective of this study was to verify overexpressed genes and evaluate their relation to the organometallic biosynthesis in this microorganism. P. aeruginosa LV strain was cultured in presence and absence of copper chloride. Two methods were used for transcriptomic analysis, genome reference-guided assembly and de novo assembly. The genome referenced analysis identified nine upregulated genes when bacteria were exposed to copper chloride, while the De Novo Assembly identified twelve upregulated genes. Nineteen genes can be related to an increased microbial metabolism for the extrusion process of exceeding intracellular copper. Two important genes are related to the biosynthesis of phenazine and tetrapyrroles compounds, which can be involved in the bioremediation of intracellular copper and biosynthesis of the organometallic compound. Additional studies are being carried out to further prove the function of the described genes and relate them to the biosynthetic pathway of the organometallic compound.

  5. The emergence of multidrug-resistant Pseudomonas aeruginosa in cystic fibrosis patients on inhaled antibiotics

    Directory of Open Access Journals (Sweden)

    Atqah AbdulWahab

    2017-01-01

    Full Text Available Introduction: Multidrug-resistant Pseudomonas aeruginosa (MDR-PA is an important and growing issue in the care of patients with cystic fibrosis (CF, and a major cause of morbidity and mortality. Objective: The objective of the study was to describe the frequency of MDR-PA recovered from the lower respiratory samples of pediatric and adult CF patients, and its antibiotic resistance pattern to commonly used antimicrobial agents including β-lactams, aminoglycosides, and fluoroquinolones. Materials and Methods: The lower respiratory isolates of P. aeruginosa were obtained from inpatients and outpatients CF clinics from a tertiary care teaching hospital for the period from October 2014 to September 2015. The identification and antimicrobial susceptibility for all the isolates were performed by using the BD Phoenix™ and E-test in compliance with Clinical and Laboratory Standards Institute (CLSI guidelines. Results: A total of 61 P. aeruginosa samples were isolated from thirty CF patients from twenty families. Twelve sputum samples were positive for MDR-PA (seven nonmucoid and five mucoid isolates from five CF patients (five families with moderate-to-very severe lung disease given MDR-PA frequency of 19.7%. The median age of the study group was 20 (range 10–30 years. Three CF patients were on chronic inhaled tobramycin and two on nebulized colistin. The antimicrobial patterns of isolates MDR-PA showed the highest rate of resistance toward each gentamycin, amikacin, and cefepime (100%, followed by 91.7% to ciprofloxacin, 75% to tobramycin, 58.3% to meropenem, and 50% to piperacillin-tazobactam. None of the isolates were resistant to colistin during the study period. Conclusion: The study results emphasize that the emergence of a significant problem in the clinical isolates of P. aeruginosa in CF patients that dictate appropriate attention to the antibiotic management after proper surveillance.

  6. New Insights about Antibiotic Production by Pseudomonas aeruginosa: A Gene Expression Analysis

    Directory of Open Access Journals (Sweden)

    Bárbara Gionco

    2017-09-01

    Full Text Available The bacterial resistance for antibiotics is one of the most important problems in public health and only a small number of new products are in development. Antagonistic microorganisms from soil are a promising source of new candidate molecules. Products of secondary metabolism confer adaptive advantages for their producer, in the competition for nutrients in the microbial community. The biosynthesis process of compounds with antibiotic activity is the key to optimize their production and the transcriptomic study of microorganisms is of great benefit for the discovery of these metabolic pathways. Pseudomonas aeruginosa LV strain growing in the presence of copper chloride produces a bioactive organometallic compound, which has a potent antimicrobial activity against various microorganisms. The objective of this study was to verify overexpressed genes and evaluate their relation to the organometallic biosynthesis in this microorganism. P. aeruginosa LV strain was cultured in presence and absence of copper chloride. Two methods were used for transcriptomic analysis, genome reference-guided assembly and de novo assembly. The genome referenced analysis identified nine upregulated genes when bacteria were exposed to copper chloride, while the De Novo Assembly identified 12 upregulated genes. Nineteen genes can be related to an increased microbial metabolism for the extrusion process of exceeding intracellular copper. Two important genes are related to the biosynthesis of phenazine and tetrapyrroles compounds, which can be involved in the bioremediation of intracellular copper and we suggesting that may involve in the biosynthesis of the organometallic compound. Additional studies are being carried out to further prove the function of the described genes and relate them to the biosynthetic pathway of the organometallic compound.

  7. Adaptation and Antibiotic Tolerance of Anaerobic Burkholderia pseudomallei ▿ †

    Science.gov (United States)

    Hamad, Mohamad A.; Austin, Chad R.; Stewart, Amanda L.; Higgins, Mike; Vázquez-Torres, Andrés; Voskuil, Martin I.

    2011-01-01

    The Gram-negative bacterium Burkholderia pseudomallei is the etiological agent of melioidosis and is remarkably resistant to most classes of antibacterials. Even after months of treatment with antibacterials that are relatively effective in vitro, there is a high rate of treatment failure, indicating that this pathogen alters its patterns of antibacterial susceptibility in response to cues encountered in the host. The pathology of melioidosis indicates that B. pseudomallei encounters host microenvironments that limit aerobic respiration, including the lack of oxygen found in abscesses and in the presence of nitric oxide produced by macrophages. We investigated whether B. pseudomallei could survive in a nonreplicating, oxygen-deprived state and determined if this physiological state was tolerant of conventional antibacterials. B. pseudomallei survived initial anaerobiosis, especially under moderately acidic conditions similar to those found in abscesses. Microarray expression profiling indicated a major shift in the physiological state of hypoxic B. pseudomallei, including induction of a variety of typical anaerobic-environment-responsive genes and genes that appear specific to anaerobic B. pseudomallei. Interestingly, anaerobic B. pseudomallei was unaffected by antibacterials typically used in therapy. However, it was exquisitely sensitive to drugs used against anaerobic pathogens. After several weeks of anaerobic culture, a significant loss of viability was observed. However, a stable subpopulation that maintained complete viability for at least 1 year was established. Thus, during the course of human infection, if a minor subpopulation of bacteria inhabited an oxygen-restricted environment, it might be indifferent to traditional therapy but susceptible to antibiotics frequently used to treat anaerobic infections. PMID:21537012

  8. Effect of Pseudomonas contamination or antibiotic decontamination of the GI tract on acute radiation lethality after neutron or gamma irradiation

    International Nuclear Information System (INIS)

    Geraci, J.P.; Jackson, K.L.; Mariano, M.S.

    1985-01-01

    The influence of antibiotic decontamination of Pseudomonas contamination of the GI tract prior to whole-body neutron or gamma irradiation was studied. It was observed that for fission neutron doses greater than 5.5 Gy, cyclotron-produced neutron doses greater than 6.7 Gy, and 137Cs gamma-ray doses greater than 14.4 Gy, the median survival time of untreated rats was relatively constant at 4.2 to 4.5 days, indicating death was due to intestinal injury. Within the dose range of 3.5 to 5.5 Gy of fission neutrons, 4.9 to 6.7 Gy of cyclotron-produced neutrons, and 9.6 to 14.4 Gy of gamma rays, median survival time of these animals was inversely related to dose and varied from 12 to 4.6 days. This change in survival time with dose reflects a transition in the mechanisms of acute radiation death from pure hematopoietic, to a combination of intestinal and hematopoietic, to pure intestinal death. Decontamination of the GI tract with antibiotics prior to irradiation increased median survival time 1 to 5 days in this transitional dose range. Contamination of the intestinal flora with Pseudomonas aeruginosa prior to irradiation reduced median survival time 1 to 5 days in the same radiation dose range. Pseudomonas-contaminated animals irradiated within this transitional dose range had maximum concentrations of total bacteria and Pseudomonas in their livers at the time of death. However, liver bacteria concentration was usually higher in gamma-irradiated animals, due to a smaller contribution of hematopoietic injury in neutron-irradiated animals. The effects of both decontamination of the GI tract and Pseudomonas contamination of the GI tract were negligible in the range of doses in which median survival time was dose independent, i.e., in the pure intestinal death dose range

  9. Synergistic Effect of 14-Alpha-Lipoyl Andrographolide and Various Antibiotics on the Formation of Biofilms and Production of Exopolysaccharide and Pyocyanin by Pseudomonas aeruginosa▿

    OpenAIRE

    Zeng, Xiangping; Liu, Xiangyang; Bian, Jiang; Pei, Gang; Dai, Huanqin; Polyak, Steven W.; Song, Fuhang; Ma, Li; Wang, Yuqiang; Zhang, Lixin

    2011-01-01

    Pseudomonas aeruginosa produces a biofilm that provides the bacteria with an effective barrier against antibiotics. Here, we investigated the synergy of various antibiotics with 14-alpha-lipoyl andrographolide (AL-1), focusing upon synthesis of the biofilm. AL-1 also inhibited the production of the exopolysaccharide and pyocyanin components. We propose that AL-1 may potentially serve as a cotherapy to combat P. aeruginosa.

  10. Synergistic effect of 14-alpha-lipoyl andrographolide and various antibiotics on the formation of biofilms and production of exopolysaccharide and pyocyanin by Pseudomonas aeruginosa.

    Science.gov (United States)

    Zeng, Xiangping; Liu, Xiangyang; Bian, Jiang; Pei, Gang; Dai, Huanqin; Polyak, Steven W; Song, Fuhang; Ma, Li; Wang, Yuqiang; Zhang, Lixin

    2011-06-01

    Pseudomonas aeruginosa produces a biofilm that provides the bacteria with an effective barrier against antibiotics. Here, we investigated the synergy of various antibiotics with 14-alpha-lipoyl andrographolide (AL-1), focusing upon synthesis of the biofilm. AL-1 also inhibited the production of the exopolysaccharide and pyocyanin components. We propose that AL-1 may potentially serve as a cotherapy to combat P. aeruginosa.

  11. Antimicrobial Tolerance of Pseudomonas aeruginosa Biofilms Is Activated during an Early Developmental Stage and Requires the Two-Component Hybrid SagS

    Science.gov (United States)

    Gupta, Kajal; Marques, Cláudia N. H.; Petrova, Olga E.

    2013-01-01

    A hallmark characteristic of biofilms is their extraordinary tolerance to antimicrobial agents. While multiple factors are thought to contribute to the high level of antimicrobial tolerance of biofilms, little is known about the timing of induction of biofilm tolerance. Here, we asked when over the course of their development do biofilms gain their tolerance to antimicrobial agents? We demonstrate that in Pseudomonas aeruginosa, biofilm tolerance is linked to biofilm development, with transition to the irreversible attachment stage regulated by the two-component hybrid SagS, marking the timing when biofilms switch to the high-level tolerance phenotype. Inactivation of sagS rendered biofilms but not planktonic cells more susceptible to tobramycin, norfloxacin, and hydrogen peroxide. Moreover, inactivation of sagS also eliminated the recalcitrance of biofilms to killing by bactericidal antimicrobial agents, a phenotype comparable to that observed upon inactivation of brlR, which encodes a MerR-like transcriptional regulator required for biofilm tolerance. Multicopy expression of brlR in a ΔsagS mutant restored biofilm resistance and recalcitrance to killing by bactericidal antibiotics to wild-type levels. In contrast, expression of sagS did not restore the susceptibility phenotype of ΔbrlR mutant biofilms to wild-type levels, indicating that BrlR functions downstream of SagS. Inactivation of sagS correlated with reduced BrlR levels in biofilms, with the produced BrlR being impaired in binding to the previously described BrlR-activated promoters of the two multidrug efflux pump operons mexAB-oprM and mexEF-oprN. Our findings demonstrate that biofilm tolerance is linked to early biofilm development and SagS, with SagS contributing indirectly to BrlR activation. PMID:23995639

  12. Evaluation of combinations of putative anti-biofilm agents and antibiotics to eradicate biofilms of Staphylococcus aureus and Pseudomonas aeruginosa.

    Science.gov (United States)

    Belfield, Katherine; Bayston, Roger; Hajduk, Nadzieja; Levell, Georgia; Birchall, John P; Daniel, Matija

    2017-09-01

    To evaluate potential anti-biofilm agents for their ability to enhance the activity of antibiotics for local treatment of localized biofilm infections. Staphylococcus aureus and Pseudomonas aeruginosa in vitro biofilm models were developed. The putative antibiotic enhancers N-acetylcysteine, acetylsalicylic acid, sodium salicylate, recombinant human deoxyribonuclease I, dispersin B, hydrogen peroxide and Johnson's Baby Shampoo (JBS) were tested for their anti-biofilm activity alone and their ability to enhance the activity of antibiotics for 7 or 14 days, against 5 day old biofilms. The antibiotic enhancers were paired with rifampicin and clindamycin against S. aureus and gentamicin and ciprofloxacin against P. aeruginosa. Isolates from biofilms that were not eradicated were tested for antibiotic resistance. Antibiotic levels 10× MIC and 100× MIC significantly reduced biofilm, but did not consistently eradicate it. Antibiotics at 100× MIC with 10% JBS for 14 days was the only treatment to eradicate both staphylococcal and pseudomonal biofilms. Recombinant human deoxyribonuclease I significantly reduced staphylococcal biofilm. Emergence of resistance of surviving isolates was minimal and was often associated with the small colony variant phenotype. JBS enhanced the activity of antibiotics and several other promising anti-biofilm agents were identified. Antibiotics with 10% JBS eradicated biofilms produced by both organisms. Such combinations might be useful in local treatment of localized biofilm infections. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Rapid disc diffusion antibiotic susceptibility testing for Pseudomonas aeruginosa, Acinetobacter baumannii and Enterococcus spp.

    Science.gov (United States)

    Hombach, Michael; Jetter, Marion; Blöchliger, Nicolas; Kolesnik-Goldmann, Natalia; Keller, Peter M; Böttger, Erik C

    2018-01-01

    Abstract Background We investigated the feasibility of rapid disc diffusion antibiotic susceptibility testing (rAST) with reading of inhibition zones after 6 and/or 8 h of incubation for Enterococcus faecalis, Enterococcus faecium, Pseudomonas aeruginosa and Acinetobacter baumannii. In addition, we evaluated discrimination of resistant populations from the WT populations at early timepoints and the requirement for clinical breakpoint adaptations for proper interpretation of rAST data. Methods In total, 815 clinical strains [E. faecalis (n = 135), E. faecium (n = 227), P. aeruginosa (n = 295) and A. baumannii (n = 158)] were included in this study. Disc diffusion plates were streaked, incubated and imaged using the WASPLabTM automation system. WT populations and non-WT populations were defined using epidemiological cut-offs. Results and conclusions rAST at 6 and 8 h was possible for A. baumannii and enterococci with readability of inhibition zones >90%. Overall categorical agreement of rAST at 6 h with AST at 18 h was 97.2%, 97.4% and 95.3% for E. faecalis, E. faecium and A. baumannii, respectively. With few exceptions, major categorization error rates were <1% for A. baumannii, and vancomycin-resistant E. faecium were clearly separated from the WT at 6 h. For P. aeruginosa the average readability of inhibition zones was 68.9% at 8 h and we found an overall categorical agreement of 94.8%. Adaptations of clinical breakpoints and/or introduction of technical buffer zones, preferably based on aggregated population data from various epidemiological settings, are required for proper interpretation of rAST. PMID:29186434

  14. Obg and Membrane Depolarization Are Part of a Microbial Bet-Hedging Strategy that Leads to Antibiotic Tolerance.

    Science.gov (United States)

    Verstraeten, Natalie; Knapen, Wouter Joris; Kint, Cyrielle Ines; Liebens, Veerle; Van den Bergh, Bram; Dewachter, Liselot; Michiels, Joran Elie; Fu, Qiang; David, Charlotte Claudia; Fierro, Ana Carolina; Marchal, Kathleen; Beirlant, Jan; Versées, Wim; Hofkens, Johan; Jansen, Maarten; Fauvart, Maarten; Michiels, Jan

    2015-07-02

    Within bacterial populations, a small fraction of persister cells is transiently capable of surviving exposure to lethal doses of antibiotics. As a bet-hedging strategy, persistence levels are determined both by stochastic induction and by environmental stimuli called responsive diversification. Little is known about the mechanisms that link the low frequency of persisters to environmental signals. Our results support a central role for the conserved GTPase Obg in determining persistence in Escherichia coli in response to nutrient starvation. Obg-mediated persistence requires the stringent response alarmone (p)ppGpp and proceeds through transcriptional control of the hokB-sokB type I toxin-antitoxin module. In individual cells, increased Obg levels induce HokB expression, which in turn results in a collapse of the membrane potential, leading to dormancy. Obg also controls persistence in Pseudomonas aeruginosa and thus constitutes a conserved regulator of antibiotic tolerance. Combined, our findings signify an important step toward unraveling shared genetic mechanisms underlying persistence. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Antibiotic resistant Pseudomonas spp. in the aquatic environment: A prevalence study under tropical and temperate climate conditions.

    Science.gov (United States)

    Devarajan, Naresh; Köhler, Thilo; Sivalingam, Periyasamy; van Delden, Christian; Mulaji, Crispin K; Mpiana, Pius T; Ibelings, Bastiaan W; Poté, John

    2017-05-15

    Microbial populations which are resistant to antibiotics are an emerging environmental concern with potentially serious implications for public health. Thus, there is a growing concern in exploring the occurrence of antibiotic resistance in the environment with no limitations to the factors that contribute to their emergence. The aquatic environment is considered to be a hot-spot for the acquisition and spread of antibiotic resistance due to pollution with emerging contaminants derived from anthropogenic activities. In this study, we report on the isolation and characterization of 141 Pseudomonas spp. from aquatic sediments receiving partially (un)treated hospital and communal effluents from three distinct geographical locations: Democratic Republic of the Congo (DRC), India (IN), and Switzerland (CH). P. putida (42%) and P. aeruginosa (39%) were the dominant Pseudomonas species. The highest frequency of antibiotic resistance against eight anti-pseudomonas agents was found among IN isolates (35-60%), followed by DRC (18-50%) and CH (12-54%). CTX-M was the most frequent β-lactamase found in CH (47% of isolates), while VIM-1 was dominant in isolates from DRC (61%) and IN (29%). NDM-1 was found in 29% of the total IN isolates and surprisingly also in 6% of CH isolates. Chromosomally-encoded efflux mechanisms were overexpressed in P. aeruginosa isolates from all three geographic locations. In vitro conjugative transfers of antibiotic resistance plasmids occurred more frequently under tropical temperatures (30 and 37 °C) than under temperate conditions (10 °C). The presence of Extended Spectrum β-lactamases (ESBLs) and Metallo β-lactamases (MBLs) in the isolates from environmental samples has important implications for humans who depend on public water supply and sanitation facilities. To our knowledge, this is the first study to demonstrate a comparison between treated/untreated effluents from urban and hospital settings as a source of microbial resistance

  16. Correlation between antibiotic and biocide resistance in mesophilic and psychrotrophic Pseudomonas spp. isolated from slaughterhouse surfaces throughout meat chain production.

    Science.gov (United States)

    Lavilla Lerma, Leyre; Benomar, Nabil; Casado Muñoz, María del Carmen; Gálvez, Antonio; Abriouel, Hikmate

    2015-10-01

    The aim of this study was to evaluate biocide susceptibility in mesophilic and psychrotrophic pseudomonads isolated from surfaces of a goat and lamb slaughterhouse, which was representative of the region. To determine biocide resistance in pseudomonads, we determined for the first time the epidemiological cut-off values (ECOFFs) of benzalkonium, cetrimide, chlorhexidine, hexachlorophene, P3 oxonia, polyhexamethylene guanidine hydrochloride (PHMG), topax 66 and triclosan being generally very similar in different Pseudomonas spp. with some exceptions. Thus, resistance of pseudomonads was mainly shown to triclosan, and in lesser extent to cetrimide and benzalkonium chloride depending on the species, however they were highly susceptible to industrial formulations of biocides. By means of statistical analysis, positive correlations between antibiotics, biocides and both antimicrobials in pseudomonads were detected suggesting a co- or cross resistance between different antimicrobials in goat and lamb slaughterhouse environment. Cross-resistance between biocides and antibiotics in pseudomonads were especially detected between PHMG or triclosan and different antibiotics depending on the biocide and the population type. Thus, the use of those biocides as disinfectant in slaughterhouse zones must be carefully evaluated because of the selection pressure effect of antimicrobials on the emergence of resistant bacteria which could be spread to the consumer. It is noteworthy that specific industrial formulations such as topax 66 and oxonia P3 showed few correlations with antibiotics (none or 1-2 antibiotics) which should be taken into consideration for disinfection practices in goat and lamb slaughterhouse. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. The consequences of being in an infectious biofilm – microenvironmental conditions governing antibiotic tolerance

    DEFF Research Database (Denmark)

    Sønderholm, Majken; Bjarnsholt, Thomas; Alhede, Maria

    2017-01-01

    The main driver behind biofilm research is the desire to understand the mechanisms governing the antibiotic tolerance of biofilm-growing bacteria found in chronic bacterial infections. Rather than genetic traits, several physical and chemical traits of the biofilm have been shown to be attributable...... to antibiotic tolerance. During infection, bacteria in biofilms exhibit slow growth and a low metabolic state due to O2 limitation imposed by intense O2 consumption of polymorphonuclear leukocytes or metabolically active bacteria in the biofilm periphery. Due to variable O2 availability throughout the infection......-growing bacteria. This review summarizes knowledge about the links between the microenvironment of biofilms in chronic infections and their tolerance against antibiotics...

  18. Cecum lymph node dendritic cells harbor slow-growing bacteria phenotypically tolerant to antibiotic treatment.

    Directory of Open Access Journals (Sweden)

    Patrick Kaiser

    2014-02-01

    Full Text Available In vivo, antibiotics are often much less efficient than ex vivo and relapses can occur. The reasons for poor in vivo activity are still not completely understood. We have studied the fluoroquinolone antibiotic ciprofloxacin in an animal model for complicated Salmonellosis. High-dose ciprofloxacin treatment efficiently reduced pathogen loads in feces and most organs. However, the cecum draining lymph node (cLN, the gut tissue, and the spleen retained surviving bacteria. In cLN, approximately 10%-20% of the bacteria remained viable. These phenotypically tolerant bacteria lodged mostly within CD103⁺CX₃CR1⁻CD11c⁺ dendritic cells, remained genetically susceptible to ciprofloxacin, were sufficient to reinitiate infection after the end of the therapy, and displayed an extremely slow growth rate, as shown by mathematical analysis of infections with mixed inocula and segregative plasmid experiments. The slow growth was sufficient to explain recalcitrance to antibiotics treatment. Therefore, slow-growing antibiotic-tolerant bacteria lodged within dendritic cells can explain poor in vivo antibiotic activity and relapse. Administration of LPS or CpG, known elicitors of innate immune defense, reduced the loads of tolerant bacteria. Thus, manipulating innate immunity may augment the in vivo activity of antibiotics.

  19. Transcriptome Analysis of Induced Systemic Drought Tolerance Elicited by Pseudomonas chlororaphis O6 in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Song-Mi Cho

    2013-06-01

    Full Text Available Root colonization by Pseudomonas chlororaphis O6 induces systemic drought tolerance in Arabidopsis thaliana. Microarray analysis was performed using the 22,800-gene Affymetrix GeneChips to identify differentially-expressed genes from plants colonized with or without P. chlororaphis O6 under drought stressed conditions or normal growth conditions. Root colonization in plants grown under regular irrigation condition increased transcript accumulation from genes associated with defense, response to reactive oxygen species, and auxin- and jasmonic acid-responsive genes, but decreased transcription factors associated with ethylene and abscisic acid signaling. The cluster of genes involved in plant disease resistance were up-regulated, but the set of drought signaling response genes were down-regulated in the P. chlororaphis O6-colonized under drought stress plants compared to those of the drought stressed plants without bacterial treatment. Transcripts of the jasmonic acid-marker genes, VSP1 and pdf-1.2, the salicylic acid regulated gene, PR-1, and the ethylene-response gene, HEL, also were up-regulated in plants colonized by P. chlororaphis O6, but differed in their responsiveness to drought stress. These data show how gene expression in plants lacking adequate water can be remarkably influenced by microbial colonization leading to plant protection, and the activation of the plant defense signal pathway induced by root colonization of P. chlororaphis O6 might be a key element for induced systemic tolerance by microbes.

  20. Differential transcriptional response to antibiotics by Pseudomonas putida DOT-T1E

    DEFF Research Database (Denmark)

    Molina-Santiago, Carlos; Daddaoua, Abdelali; Gómez Lozano, María

    2015-01-01

    Multi-drug resistant bacteria are a major threat to humanity, especially because the current battery of known antibiotics is not sufficient to combat infections produced by these microbes. Therefore, the study of how current antibiotics act and how bacteria defend themselves against antibiotics i...

  1. Effects of environmental conditions on the morphologic change of Pseudomonas aeruginosa and its association with antibiotic resistance in burn patients

    Directory of Open Access Journals (Sweden)

    Mohsen Moghoofei

    2015-12-01

    Full Text Available Introduction: Pseudomonas aeruginosa is an aerobic gram-negative bacteria, which causes hospital infections. Bacteria under stress, such as lack of food, pH and osmotic pressure change and antibiotic stress transforms its morphology to coccoid form. In the bacill form due to changes in the peptidoglycan cell wall, membrane lipids and decreased metabolic activity, bacteria resistant to antibiotics. Due to an increase in mortality in burn patients and important problem of antibiotic resistance in P.aeruginosa the researcher decided to study the factors affecting on morphologic change to coccoid form. Materials and methods: In this study P.aeruginosa strains obtained from clinical samples of burned patients (8 samples were taken from the wound by Infectious Disease Specialist and standard strain ATCC 27853 were used. Samples were confirmed by biochemical tests and PCR by 16srDNA primer. Then bacteria were put under lack of food and antibiotic stress invitro. After that bacterial morphology was examined on different days by digital DP 72-BX 51 microscope to 60 days. After induction coccoid forms, bacterial viability was confirmed by flow cytometry. Results: Bacteria begin to change morphology from 5 days for antibiotic stress and 10 days for other stress. Changing morphology was initially elongate bacilli, U shape and finally the coccoid form was seen. Discussion and conclusion: Changing morphology of bacilli to coccoid bacteria that are the result of stress on the bacteria which enter the body can lead to bacterial resistance to antibiotics and have grave consequences for the patient.

  2. Reversible antibiotic tolerance induced in Staphylococcus aureus by concurrent drug exposure

    DEFF Research Database (Denmark)

    Haaber, Jakob Krause; Friberg, Cathrine; McCreary, Mark

    2015-01-01

    UNLABELLED: Resistance of Staphylococcus aureus to beta-lactam antibiotics has led to increasing use of the glycopeptide antibiotic vancomycin as a life-saving treatment for major S. aureus infections. Coinfection by an unrelated bacterial species may necessitate concurrent treatment with a second...... antibiotic that targets the coinfecting pathogen. While investigating factors that affect bacterial antibiotic sensitivity, we discovered that susceptibility of S. aureus to vancomycin is reduced by concurrent exposure to colistin, a cationic peptide antimicrobial employed to treat infections by Gram......-negative pathogens. We show that colistin-induced vancomycin tolerance persists only as long as the inducer is present and is accompanied by gene expression changes similar to those resulting from mutations that produce stably inherited reduction of vancomycin sensitivity (vancomycin-intermediate S. aureus [VISA...

  3. Simultaneous and quantitative monitoring of co-cultured Pseudomonas aeruginosa and Staphylococcus aureus with antibiotics on a diffusometric platform

    Science.gov (United States)

    Chung, Chih-Yao; Wang, Jhih-Cheng; Chuang, Han-Sheng

    2017-04-01

    Successful treatments against bacterial infections depend on antimicrobial susceptibility testing (AST). However, conventional AST requires more than 24 h to obtain an outcome, thereby contributing to high patient mortality. An antibiotic therapy based on experiences is therefore necessary for saving lives and escalating the emergence of multidrug-resistant pathogens. Accordingly, a fast and effective drug screen is necessary for the appropriate administration of antibiotics. The mixed pathogenic nature of infectious diseases emphasizes the need to develop an assay system for polymicrobial infections. On this basis, we present a novel technique for simultaneous and quantitative monitoring of co-cultured microorganisms by coupling optical diffusometry with bead-based immunoassays. This simple integration simultaneously achieves a rapid AST analysis for two pathogens. Triple color particles were simultaneously recorded and subsequently analyzed by functionalizing different fluorescent color particles with dissimilar pathogen-specific antibodies. Results suggested that the effect of the antibiotic, gentamicin, on co-cultured Pseudomonas aeruginosa and Staphylococcus aureus was effectively distinguished by the proposed technique. This study revealed a multiplexed and time-saving (within 2 h) platform with a small sample volume (~0.5 μL) and a low initial bacterial count (50 CFU per droplet, ~105 CFU/mL) for continuously monitoring the growth of co-cultured microorganisms. This technique provides insights into timely therapies against polymicrobial diseases in the near future.

  4. 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

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

    Science.gov (United States)

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

    2016-01-01

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

  6. Influence of regular reporting on local Pseudomonas aeruginosa and Acinetobacter spp. sensitivity to antibiotics on consumption of antibiotics and resistance patterns.

    Science.gov (United States)

    Djordjevic, Z M; Folic, M M; Jankovic, S M

    2017-10-01

    Regular surveillance of antimicrobial resistance is an important component of multifaceted interventions directed at the problem with resistance of bacteria causing healthcare-associated infections (HAIs) in intensive care units (ICUs). Our aim was to analyse antimicrobial consumption and resistance among isolates of Pseudomonas aeruginosa and Acinetobacter spp. causing HAIs, before and after the introduction of mandatory reporting of resistance patterns to prescribers. A retrospective observational study was conducted between January 2011 and December 2015, at an interdisciplinary ICU of the Clinical Centre Kragujevac, Serbia. The intervention consisted of continuous resistance monitoring of all bacterial isolates from ICU patients and biannual reporting of results per isolate to prescribers across the hospital. Both utilization of antibiotics and density of resistant isolates of P. aeruginosa and Acinetobacter spp. were followed within the ICU. Resistance densities of P. aeruginosa to all tested antimicrobials were lower in 2015, in comparison with 2011. Although isolates of Acinetobacter spp. had lower resistance density in 2015 than in 2011 to the majority of investigated antibiotics, a statistically significant decrease was noted only for piperacillin/tazobactam. Statistically significant decreasing trends of consumption were recorded for third-generation cephalosporins, aminoglycosides and fluoroquinolones, whereas for the piperacillin/tazobactam, ampicillin/sulbactam and carbapenems, utilization trends were decreasing, but without statistical significance. In the same period, increasing trends of consumption were observed for tigecycline and colistin. Regular monitoring of resistance of bacterial isolates in ICUs and reporting of summary results to prescribers may lead to a significant decrease in utilization of some antibiotics and slow restoration of P. aeruginosa and Acinetobacter spp. susceptibility. © 2017 John Wiley & Sons Ltd.

  7. Case Report: Dual nebulised antibiotics among adults with cystic fibrosis and chronic Pseudomonas infection [version 2; referees: 1 approved, 2 approved with reservations

    Directory of Open Access Journals (Sweden)

    Nina Mann

    2018-02-01

    Full Text Available Pulmonary exacerbations in adults with cystic fibrosis (CF and chronic Pseudomonas aeruginosa (Psae infection are usually treated with dual intravenous antibiotics for 14 days, despite the lack of evidence for best practice. Intravenous antibiotics are commonly associated with various systemic adverse effects, including renal failure and ototoxicity. Inhaled antibiotics are less likely to cause systematic adverse effects, yet can achieve airway concentrations well above conventional minimum inhibitory concentrations. Typically one inhaled antibiotic is used at a time, but dual inhaled antibiotics (i.e. concomitant use of two different inhaled antibiotics may have synergistic effect and achieve better results in the treatment of exacerbations. We presented anecdotal evidence for the use of dual inhaled antibiotics as an acute treatment for exacerbations, in the form of a case report. A female in her early thirties with CF and chronic Psae infection improved her FEV1 by 5% and 2% with two courses of dual inhaled antibiotics to treat exacerbations in 2016. In contrast, her FEV1 changed by 2%, –2%, 0% and 2%, respectively, with four courses of dual intravenous antibiotics in 2016. Baseline FEV1 was similar prior to all six courses of treatments. The greater FEV1 improvements with dual inhaled antibiotics compared to dual intravenous antibiotics suggest the potential role of using dual inhaled antibiotics to treat exacerbations among adults with CF and chronic Psae infection, especially since a greater choice of inhaled anti-pseudomonal antibiotics is now available. A previous study in 1985 has looked at the concomitant administration of inhaled tobramycin and carbenicillin, by reconstituting antibiotics designed for parenteral administration. To our knowledge, this is the first literature to describe the concomitant use of two different antibiotics specifically developed for delivery via the inhaled route.

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

    DEFF Research Database (Denmark)

    Hengzhuang, Wang; Høiby, Niels; Ciofu, Oana

    2014-01-01

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

  9. Marine Pseudomonas putida: a potential source of antimicrobial substances against antibiotic-resistant bacteria

    Directory of Open Access Journals (Sweden)

    Palloma Rodrigues Marinho

    2009-08-01

    Full Text Available Bacteria isolated from marine sponges found off the coast of Rio de Janeiro, Brazil, were screened for the production of antimicrobial substances. We report a new Pseudomonas putida strain (designated P. putida Mm3 isolated from the sponge Mycale microsigmatosa that produces a powerful antimicrobial substance active against multidrug-resistant bacteria. P. putida Mm3 was identified on the basis of 16S rRNA gene sequencing and phenotypic tests. Molecular typing for Mm3 was performed by RAPD-PCR and comparison of the results to other Pseudomonas strains. Our results contribute to the search for new antimicrobial agents, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria.

  10. Marine Pseudomonas putida: a potential source of antimicrobial substances against antibiotic-resistant bacteria.

    Science.gov (United States)

    Marinho, Palloma Rodrigues; Moreira, Ana Paula Barbosa; Pellegrino, Flávia Lúcia Piffano Costa; Muricy, Guilherme; Bastos, Maria do Carmo de Freire; Santos, Kátia Regina Netto dos; Giambiagi-deMarval, Marcia; Laport, Marinella Silva

    2009-08-01

    Bacteria isolated from marine sponges found off the coast of Rio de Janeiro, Brazil, were screened for the production of antimicrobial substances. We report a new Pseudomonas putida strain (designated P. putida Mm3) isolated from the sponge Mycale microsigmatosa that produces a powerful antimicrobial substance active against multidrug-resistant bacteria. P. putida Mm3 was identified on the basis of 16S rRNA gene sequencing and phenotypic tests. Molecular typing for Mm3 was performed by RAPD-PCR and comparison of the results to other Pseudomonas strains. Our results contribute to the search for new antimicrobial agents, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria.

  11. Tolerance of Pseudomonas aeruginosa in in-vitro biofilms to high-level peracetic acid disinfection.

    Science.gov (United States)

    Akinbobola, A B; Sherry, L; Mckay, W G; Ramage, G; Williams, C

    2017-10-01

    Biofilm has been suggested as a cause of disinfection failures in flexible endoscopes where no lapses in the decontamination procedure can be identified. To test this theory, the activity of peracetic acid, one of the widely used disinfectants in the reprocessing of flexible endoscopes, was evaluated against both planktonic and sessile communities of Pseudomonas aeruginosa. To investigate the ability of P. aeruginosa biofilm to survive high-level peracetic acid disinfection. The susceptibility of planktonic cells of P. aeruginosa and biofilms aged 24, 48, 96, and 192 h to peracetic acid was evaluated by estimating their viability using resazurin viability and plate count methods. The biomass of the P. aeruginosa biofilms was also quantified using Crystal Violet assay. Planktonic cells of P. aeruginosa were treated with 5-30 ppm concentration of peracetic acid in the presence of 3.0 g/L of bovine serum albumin (BSA) for 5 min. Biofilms of P. aeruginosa were also treated with various peracetic acid concentrations (100-3000 ppm) for 5 min. Planktonic cells of P. aeruginosa were eradicated by 20 ppm of peracetic acid, whereas biofilms showed an age-dependent tolerance to peracetic acid, and 96 h biofilm was only eradicated at peracetic acid concentration of 2500 ppm. Ninety-six-hour P. aeruginosa biofilm survives 5 min treatment with 2000 ppm of peracetic acid, which is the working concentration used in some endoscope washer-disinfectors. This implies that disinfection failure of flexible endoscopes might occur when biofilms build up in the lumens of endoscopes. Copyright © 2017. Published by Elsevier Ltd.

  12. 40 CFR 180.1114 - Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS; exemptions from the requirement of a tolerance... Tolerances § 180.1114 Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae...

  13. Increasing antibiotic resistance in preservative-tolerant bacterial strains isolated from cosmetic products.

    Science.gov (United States)

    Orús, Pilar; Gomez-Perez, Laura; Leranoz, Sonia; Berlanga, Mercedes

    2015-03-01

    To ensure the microbiological quality, consumer safety and organoleptic properties of cosmetic products, manufacturers need to comply with defined standards using several preservatives and disinfectants. A drawback regarding the use of these preservatives is the possibility of generating cross-insusceptibility to other disinfectants or preservatives, as well as cross resistance to antibiotics. Therefore, the objective of this study was to understand the adaptive mechanisms of Enterobacter gergoviae, Pseudomonas putida and Burkholderia cepacia that are involved in recurrent contamination in cosmetic products containing preservatives. Diminished susceptibility to formaldehyde-donors was detected in isolates but not to other preservatives commonly used in the cosmetics industry, although increasing resistance to different antibiotics (β-lactams, quinolones, rifampicin, and tetracycline) was demonstrated in these strains when compared with the wild-type strain. The outer membrane protein modifications and efflux mechanism activities responsible for the resistance trait were evaluated. The development of antibiotic-resistant microorganisms due to the selective pressure from preservatives included in cosmetic products could be a risk for the emergence and spread of bacterial resistance in the environment. Nevertheless, the large contribution of disinfection and preservation cannot be denied in cosmetic products. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  14. Resistance of Pseudomonas aeruginosa PAO to nalidixic acid and low levels of beta-lactam antibiotics: mapping of chromosomal genes.

    Science.gov (United States)

    Rella, M; Haas, D

    1982-01-01

    Resistance to high concentrations of nalidixic acid in Pseudomonas aeruginosa PAO was due to mutations in one locus designated nalA, which was mapped by transduction between hex-9001 and leu-10. The nalA mutants were cross-resistant to pipemidic acid, a nalidixic acid analog, at relatively low concentrations. Replicative DNA synthesis was resistant to both drugs in permeabilized cells of nalA mutants. A locus coding for low-level resistance to nalidixic acid, nalB, was cotransducible with pyrB, proC, and met-28. The nalB mutants were also resistant to low levels of pipemidic acid, novobiocin, and beta-lactam antibiotics (e.g., carbenicillin, azlocillin, and cefsulodin), but not to other drugs, such as gentamicin, rifampin, kanamycin, or tetracycline. In nalB mutants, DNA replication showed wild-type sensitivity to nalidixic acid, whereas carbenicillin-induced filamentation required higher drug levels than in the wild-type strain. Thus, nalB mutations appear to decrease cell permeability to some antibiotics. The sensitivity of replicative DNA synthesis to nalidixic acid and novobiocin was very similar in P. aeruginosa and Escherichia coli; by contrast, the concentrations of these drugs needed to inhibit growth of P. aeruginosa were higher than those reported for E. coli by one or two orders of magnitude. PMID:6821455

  15. Metallo-beta-lactamases of Pseudomonas aeruginosa--a novel mechanism resistance to beta-lactam antibiotics.

    Directory of Open Access Journals (Sweden)

    Dorota Olszańska

    2008-06-01

    Full Text Available Since about twenty years, following the introduction into therapeutic of news beta-lactam antibiotics (broad-spectrum cephalosporins, monobactams and carbapenems, a very significant number of new beta-lactamases appeared. These enzymes confer to the bacteria which put them, the means of resisting new molecules. The genetic events involved in this evolution are of two types: evolution of old enzymes by mutation and especially appearance of new genes coming for some, from bacteria of the environment. Numerous mechanisms of enzymatic resistance to the carbapenems have been described in Pseudomonas aeruginosa. The important mechanism of inactivation carbapenems is production variety of b-lactam hydrolysing enzymes associated to carbapenemases. The metallo-beta-enzymes (IMP, VIM, SPM, GIM types are the most clinically significant carbapenemases. P. aeruginosa posses MBLs and seem to have acquired them through transmissible genetic elements (plasmids or transposons associated with integron and can be transmission to other bacteria. They have reported worldwide but mostly from South East Asia and Europe. The enzymes, belonging to the molecular class B family, are the most worrisome of all beta-lactamases because they confer resistance to carbapenems and all the beta-lactams (with the exception of aztreonam and usually to aminoglycosides and quinolones. The dissemination of MBLs genes is thought to be driven by regional consumption of extended--spectrum antibiotics (e.g. cephalosporins and carbapenems, and therefore care must be taken that these drugs are not used unnecessarily.

  16. Role of the interplay between quorum sensing regulator VqsR and the Pseudomonas quinolone signal in mediating carbapenem tolerance in Pseudomonas aeruginosa.

    Science.gov (United States)

    Viducic, Darija; Murakami, Keiji; Amoh, Takashi; Ono, Tsuneko; Miyake, Yoichiro

    2017-06-01

    Pseudomonas aeruginosa coordinates its response to environmental conditions through activation of a quorum sensing (QS) system. In this study, we investigated the regulatory interaction between the QS transcriptional regulator VqsR and the Pseudomonas quinolone signal (PQS) through integration of sigma factor RpoS, and we addressed whether one of the pathways controlling carbapenem tolerance can be attributed to VqsR. We demonstrate that vqsR expression at the transcriptional level is regulated by pqsA, pqsR, and pqsE. Assessment of the transcriptional expression of vqsR, lasI, rhlI, and qscR in ΔpqsA and ΔpqsAΔrpoS mutants provided insight into pqsA- and rpoS-dependent regulation of vqsR and vqsR-controlled genes. Exogenously supplemented PQS reversed expression of vqsR and vqsR-controlled genes in the ΔpqsA mutant to wild-type levels, but failed to increase expression levels of lasI and qscR in the ΔpqsAΔrpoS mutant to levels observed in wild-type PAO1. The ΔvqsR mutant showed reduced survival when challenged with carbapenems compared to wild-type PAO1. Introduction of a pqsA mutation into the ΔvqsR mutant completely abolished its carbapenem-sensitive phenotype. We conclude that a regulatory link between PQS and vqsR exists, and that RpoS is important in their interaction. We also demonstrate that VqsR affects carbapenem tolerance. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  17. High-dose continuous infusion beta-lactam antibiotics for the treatment of resistant Pseudomonas aeruginosa infections in immunocompromised patients.

    Science.gov (United States)

    Moriyama, Brad; Henning, Stacey A; Childs, Richard; Holland, Steven M; Anderson, Victoria L; Morris, John C; Wilson, Wyndham H; Drusano, George L; Walsh, Thomas J

    2010-05-01

    To report a case series of high-dose continuous infusion beta-lactam antibiotics for the treatment of resistant Pseudomonas aeruginosa infections. Continuous infusion ceftazidime or aztreonam was administered to achieve target drug concentrations at or above the minimum inhibitory concentration, when possible, in 3 patients with P. aeruginosa infections. The maximal calculated target drug concentration was 100 mg/L. In the first patient, with primary immunodeficiency, neutropenia, and aggressive cutaneous T-cell lymphoma/leukemia, continuous infusion ceftazidime (6.5-9.6 g/day) was used to successfully treat multidrug-resistant P. aeruginosa bacteremia. In the second patient, with leukocyte adhesion deficiency type 1, continuous infusion aztreonam (8.4 g/day) was used to successfully treat multidrug-resistant P. aeruginosa wound infections. In the third patient, with severe aplastic anemia, continuous infusion ceftazidime (7-16.8 g/day) was used to treat P. aeruginosa pneumonia and bacteremia. In each patient, bacteremia cleared, infected wounds healed, and pneumonia improved in response to continuous infusion ceftazidime or aztreonam. Treatment strategies for multidrug-resistant P. aeruginosa infections are limited. A novel treatment strategy, when no other options are available, is the continuous infusion of existing beta-lactam antibiotics to maximize their pharmacodynamic activity. High-dose continuous infusion ceftazidime or aztreonam was used for the successful treatment of resistant systemic P. aeruginosa infections in 3 chronically immunocompromised patients. Continuous infusion beta-lactam antibiotics are a potentially useful treatment strategy for resistant P. aeruginosa infections in immunocompromised patients.

  18. Effect of gamma rays on antibiotic resistance of Staphylococcus aureus and Pseudomonas aeruginosa isolated from human skin

    International Nuclear Information System (INIS)

    Shokier, H. A.; EI-Adly, A.A.; Hussein, H.; Shabon, M. H.; EI-Shanshoury, I.H.

    2010-01-01

    Seventy one samples were randomly collected from patients suffering from different bacterial skin infections. Forty isolates could not grow on the artificial media after second subculture while 31 isolates were able to survive. Twenty six of them were identified as Staphylococcus aureus and 5 were identified as Pseudomonas aeruginosa. The isolated strains were tested for their susceptibilities to gentamycin, ampicillin, ciprofloxacin and amoxicillin antibiotics .Up to 88.4% of S. aureus and of 80% of P.aeruginosa isolates were found to be resistant to ampicillin. On the other. hand, about 30.7% of S. aureus and 20% of P. aeruginosa were resistant to ciprofloxacin reveals the lowest antibiotic resistance . The antibiotic sensitivity was retested for the most resistant bacterial isolates after irradiated by different doses of gamma radiation (0.5,1, 2 Gy). The previous doses increased S .aureus inhibition zone to gentamycin, from 7.5 mm for unirradiated cells to 25 mm for irradiated one. While ciprofloxacin inhibition zone increased from 1.5 cm to 3 cm in doses of 0.5 to 2.0 Gy. S. aureus sensitivity to amoxicillin increased from 0.0 to 1.0 cm inhibition zone with increase in dose from 0.5 to 2.0 Gy.While the previous doses had no effect on ampicillin resistance. The same doses increased P. aeruginosa isolate resistance. Very low doses of gamma irradiation increased S.aureus and P. aeruginosa capsule production, also increased the release rate of capsule content in both types of bacteria.

  19. Metabolic Compensation of Fitness Costs Is a General Outcome for Antibiotic-Resistant Pseudomonas aeruginosa Mutants Overexpressing Efflux Pumps.

    Science.gov (United States)

    Olivares Pacheco, Jorge; Alvarez-Ortega, Carolina; Alcalde Rico, Manuel; Martínez, José Luis

    2017-07-25

    It is generally assumed that the acquisition of antibiotic resistance is associated with a fitness cost. We have shown that overexpression of the MexEF-OprN efflux pump does not decrease the fitness of a resistant Pseudomonas aeruginosa strain compared to its wild-type counterpart. This lack of fitness cost was associated with a metabolic rewiring that includes increased expression of the anaerobic nitrate respiratory chain when cells are growing under fully aerobic conditions. It was not clear whether this metabolic compensation was exclusive to strains overexpressing MexEF-OprN or if it extended to other resistant strains that overexpress similar systems. To answer this question, we studied a set of P. aeruginosa mutants that independently overexpress the MexAB-OprM, MexCD-OprJ, or MexXY efflux pumps. We observed increased expression of the anaerobic nitrate respiratory chain in all cases, with a concomitant increase in NO 3 consumption and NO production. These efflux pumps are proton/substrate antiporters, and their overexpression may lead to intracellular H + accumulation, which may in turn offset the pH homeostasis. Indeed, all studied mutants showed a decrease in intracellular pH under anaerobic conditions. The fastest way to eliminate the excess of protons is by increasing oxygen consumption, a feature also displayed by all analyzed mutants. Taken together, our results support metabolic rewiring as a general mechanism to avoid the fitness costs derived from overexpression of P. aeruginosa multidrug efflux pumps. The development of drugs that block this metabolic "reaccommodation" might help in reducing the persistence and spread of antibiotic resistance elements among bacterial populations. IMPORTANCE It is widely accepted that the acquisition of resistance confers a fitness cost in such a way that in the absence of antibiotics, resistant populations will be outcompeted by susceptible ones. Based on this assumption, antibiotic cycling regimes have been

  20. Pesticide tolerant and phosphorus solubilizing Pseudomonas sp. strain SGRAJ09 isolated from pesticides treated Achillea clavennae rhizosphere soil.

    Science.gov (United States)

    Rajasankar, R; Manju Gayathry, G; Sathiavelu, A; Ramalingam, C; Saravanan, V S

    2013-05-01

    In this study, an attempt was made to identify an effective phosphate solubilizing bacteria from pesticide polluted field soil. Based on the formation of solubilization halo on Pikovskaya's agar, six isolates were selected and screened for pesticide tolerance and phosphate (P) solubilization ability through liquid assay. The results showed that only one strain (SGRAJ09) obtained from Achillea clavennae was found to tolerate maximum level of the pesticides tested and it was phylogenetically identified as Pseudomonas sp. It possessed a wide range of pesticide tolerance, ranging from 117 μg mL(-1) for alphamethrin to 2,600 μg mL(-1) for endosulfan. The available P concentrations increased with the maximum and double the maximum dose of monocrotophos and imidacloprid, respectively. On subjected to FT-IR and HPLC analysis, the presence of organic acids functional group in the culture broth and the production of gluconic acid as dominant acid aiding the P solubilization were identified. On comparison with control broth, monocrotophos and imidacloprid added culture broth showed quantitatively high organic acids production. In addition to gluconic acid production, citric and acetic acids were also observed in the pesticide amended broth. Furthermore, the Pseudomonas sp. strain SGRAJ09 possessed all the plant growth promoting traits tested. In presence of monocrotophos and imidacloprid, its plant growth promoting activities were lower than that of the pesticides unamended treatment.

  1. Optimization of treatment protocols to prevent de novo development of antibiotic resistance in Pseudomonas aeruginosa

    NARCIS (Netherlands)

    Feng, Yanfang

    2016-01-01

    The ever-increasing rate of drug resistant bacteria has been one of the most challenging problem worldwide. This thesis studied the following subjects with mostly the clinically leading pathogen, P. aeruginosa, as the model strain: de novo development of antibiotic resistance in patient during the

  2. Antibiotics

    Science.gov (United States)

    Antibiotics are powerful medicines that fight bacterial infections. Used properly, antibiotics can save lives. They either kill bacteria or ... natural defenses can usually take it from there. Antibiotics do not fight infections caused by viruses, such ...

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

    Science.gov (United States)

    Ciofu, Oana; Yang, Liang; Wu, Hong; Song, Zhijun; Oliver, Antonio; Høiby, Niels

    2013-01-01

    Resistance to β-lactam antibiotics is a frequent problem in Pseudomonas aeruginosa lung infection of cystic fibrosis (CF) patients. This resistance is mainly due to the hyperproduction of chromosomally encoded β-lactamase and biofilm formation. The purpose of this study was to investigate the role of β-lactamase in the pharmacokinetics (PK) and pharmacodynamics (PD) of ceftazidime and imipenem on P. aeruginosa biofilms. P. aeruginosa PAO1 and its corresponding β-lactamase-overproducing mutant, PAΔDDh2Dh3, were used in this study. Biofilms of these two strains in flow chambers, microtiter plates, and on alginate beads were treated with different concentrations of ceftazidime and imipenem. The kinetics of antibiotics on the biofilms was investigated in vitro by time-kill methods. Time-dependent killing of ceftazidime was observed in PAO1 biofilms, but concentration-dependent killing activity of ceftazidime was observed for β-lactamase-overproducing biofilms of P. aeruginosa in all three models. Ceftazidime showed time-dependent killing on planktonic PAO1 and PAΔDDh2Dh3. This difference is probably due to the special distribution and accumulation in the biofilm matrix of β-lactamase, which can hydrolyze the β-lactam antibiotics. The PK/PD indices of the AUC/MBIC and Cmax/MBIC (AUC is the area under concentration-time curve, MBIC is the minimal biofilm-inhibitory concentration, and Cmax is the maximum concentration of drug in serum) are probably the best parameters to describe the effect of ceftazidime in β-lactamase-overproducing P. aeruginosa biofilms. Meanwhile, imipenem showed time-dependent killing on both PAO1 and PAΔDDh2Dh3 biofilms. An inoculum effect of β-lactams was found for both planktonic and biofilm P. aeruginosa cells. The inoculum effect of ceftazidime for the β-lactamase-overproducing mutant PAΔDDh2Dh3 biofilms was more obvious than for PAO1 biofilms, with a requirement of higher antibiotic concentration and a longer period of treatment

  4. Clonal dissemination, emergence of mutator lineages and antibiotic resistance evolution in Pseudomonas aeruginosa cystic fibrosis chronic lung infection.

    Directory of Open Access Journals (Sweden)

    Carla López-Causapé

    Full Text Available Chronic respiratory infection by Pseudomonas aeruginosa is a major cause of mortality in cystic fibrosis (CF. We investigated the interplay between three key microbiological aspects of these infections: the occurrence of transmissible and persistent strains, the emergence of variants with enhanced mutation rates (mutators and the evolution of antibiotic resistance. For this purpose, 10 sequential isolates, covering up to an 8-year period, from each of 10 CF patients were studied. As anticipated, resistance significantly accumulated overtime, and occurred more frequently among mutator variants detected in 6 of the patients. Nevertheless, highest resistance was documented for the nonmutator CF epidemic strain LES-1 (ST-146 detected for the first time in Spain. A correlation between resistance profiles and resistance mechanisms evaluated [efflux pump (mexB, mexD, mexF, and mexY and ampC overexpression and OprD production] was not always obvious and hypersusceptibility to certain antibiotics (such as aztreonam or meropenem was frequently observed. The analysis of whole genome macrorestriction fragments through Pulsed-Field Gel Electrophoresis (PFGE revealed that a single genotype (clone FQSE-A produced persistent infections in 4 of the patients. Multilocus Sequence typing (MLST identified clone FQSE-A as the CF epidemic clone ST-274, but striking discrepancies between PFGE and MLST profiles were evidenced. While PFGE macrorestriction patterns remained stable, a new sequence type (ST-1089 was detected in two of the patients, differing from ST-274 by only two point mutations in two of the genes, each leading to a nonpreviously described allele. Moreover, detailed genetic analyses revealed that the new ST-1089 is a mutS deficient mutator lineage that evolved from the epidemic strain ST-274, acquired specific resistance mechanisms, and underwent further interpatient spread. Thus, presented results provide the first evidence of interpatient dissemination

  5. Persistent Bacteremia from Pseudomonas aeruginosa with In Vitro Resistance to the Novel Antibiotics Ceftolozane-Tazobactam and Ceftazidime-Avibactam

    Directory of Open Access Journals (Sweden)

    Louie Mar Gangcuangco

    2016-01-01

    Full Text Available Ceftazidime-avibactam and ceftolozane-tazobactam are new antimicrobials with activity against multidrug-resistant Pseudomonas aeruginosa. We present the first case of persistent P. aeruginosa bacteremia with in vitro resistance to these novel antimicrobials. A 68-year-old man with newly diagnosed follicular lymphoma was admitted to the medical intensive care unit for sepsis and right lower extremity cellulitis. The patient was placed empirically on vancomycin and piperacillin-tazobactam. Blood cultures from Day 1 of hospitalization grew P. aeruginosa susceptible to piperacillin-tazobactam and cefepime identified using VITEK 2 (Biomerieux, Lenexa, KS. Repeat blood cultures from Day 5 grew P. aeruginosa resistant to all cephalosporins, as well as to meropenem by Day 10. Susceptibility testing performed by measuring minimum inhibitory concentration by E-test (Biomerieux, Lenexa, KS revealed that blood cultures from Day 10 were resistant to ceftazidime-avibactam and ceftolozane-tazobactam. The Verigene Blood Culture-Gram-Negative (BC-GN microarray-based assay (Nanosphere, Inc., Northbrook, IL was used to investigate underlying resistance mechanism in the P. aeruginosa isolate but CTX-M, KPC, NDM, VIM, IMP, and OXA gene were not detected. This case report highlights the well-documented phenomenon of antimicrobial resistance development in P. aeruginosa even during the course of appropriate antibiotic therapy. In the era of increasing multidrug-resistant organisms, routine susceptibility testing of P. aeruginosa to ceftazidime-avibactam and ceftolozane-tazobactam is warranted. Emerging resistance mechanisms to these novel antibiotics need to be further investigated.

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

    Directory of Open Access Journals (Sweden)

    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.

  7. In vitro susceptibility of aural isolates of Pseudomonas aeruginosa to commonly used ototopical antibiotics.

    Science.gov (United States)

    Dohar, J E; Kenna, M A; Wadowsky, R M

    1996-03-01

    The choice of antimicrobial agents used to treat Pseudomonas aeruginosa infections of the ear is quite empiric. Yet in spite of this, very little has been published examining susceptibility patterns of aural isolates of P. aeruginosa. Recently, increasing concern has emerged over the development of resistance to many of the commonly used ototopical preparations with activity against P. aeruginosa. This concern stems from the fact that these preparations have been in use for a long time, and P. aeruginosa is known to develop resistance fairly readily. We prospectively studied the susceptibilities of aural isolates of P. aeruginosa in 231 consecutive children who were seen in the outpatient Pediatric Otolaryngology Department at Children's Hospital of Pittsburgh during the years 1992 and 1993. The agents tested included neomycin, polymyxin B, colistin, and norfloxacin. We found that only 17.8% of the isolates were sensitive to neomycin, as opposed to > 95% for each of the other agents tested (polymyxin B, 99.6%; colistin, 97.4%; and norfloxacin, 98.3%). This difference proved to be statistically significant (p < 0.05). Given the concern of aminoglycoside-induced ototoxicity and the high rate of neomycin resistance, we believe that further investigation of other alternative ototopic agents with activity against P. aeruginosa is warranted.

  8. DNA Polymerases ImuC and DinB Are Involved in DNA Alkylation Damage Tolerance in Pseudomonas aeruginosa and Pseudomonas putida.

    Science.gov (United States)

    Jatsenko, Tatjana; Sidorenko, Julia; Saumaa, Signe; Kivisaar, Maia

    2017-01-01

    Translesion DNA synthesis (TLS), facilitated by low-fidelity polymerases, is an important DNA damage tolerance mechanism. Here, we investigated the role and biological function of TLS polymerase ImuC (former DnaE2), generally present in bacteria lacking DNA polymerase V, and TLS polymerase DinB in response to DNA alkylation damage in Pseudomonas aeruginosa and P. putida. We found that TLS DNA polymerases ImuC and DinB ensured a protective role against N- and O-methylation induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in both P. aeruginosa and P. putida. DinB also appeared to be important for the survival of P. aeruginosa and rapidly growing P. putida cells in the presence of methyl methanesulfonate (MMS). The role of ImuC in protection against MMS-induced damage was uncovered under DinB-deficient conditions. Apart from this, both ImuC and DinB were critical for the survival of bacteria with impaired base excision repair (BER) functions upon alkylation damage, lacking DNA glycosylases AlkA and/or Tag. Here, the increased sensitivity of imuCdinB double deficient strains in comparison to single mutants suggested that the specificity of alkylated DNA lesion bypass of DinB and ImuC might also be different. Moreover, our results demonstrated that mutagenesis induced by MMS in pseudomonads was largely ImuC-dependent. Unexpectedly, we discovered that the growth temperature of bacteria affected the efficiency of DinB and ImuC in ensuring cell survival upon alkylation damage. Taken together, the results of our study disclosed the involvement of ImuC in DNA alkylation damage tolerance, especially at low temperatures, and its possible contribution to the adaptation of pseudomonads upon DNA alkylation damage via increased mutagenesis.

  9. Cadmium tolerance and antibiotic resistance in Escherichia coli isolated from waste stabilization ponds.

    Science.gov (United States)

    Patra, Sova; Das, T K; Avila, C; Cabello, V; Castillo, F; Sarkar, D; Lahiri, Susmita; Jana, B B

    2012-04-01

    The incidence pattern of cadmium tolerance and antibiotics resistance by Escherichia coli was examined periodically from the samples of water, sludge and intestine of fish raised in waste stabilization ponds in a sewage treatment plant. Samples of water and sludge were collected from all the selected ponds and were monitored for total counts of fecal coliform (FC), total coliform (TC) and the population of Escherichia coli, which was also obtained from the intestine of fishes. Total counts of both FC and TC as well as counts of E. coli were markedly reduced from the facultative pond to the last maturation pond. Tolerance limit to cadmium by E. coli tended to decline as the distance of the sewage effluent from the source increased; the effective lethal concentration of cadmium ranged from 0.1 mM in split chamber to 0.05 mM in first maturation pond. E. coli isolated from water, sludge and fish gut were sensitive to seven out of ten antibiotics tested. It appears that holistic functions mediated through the mutualistic growth of micro algae and heterotrophic bacteria in the waste stabilization ponds were responsible for the promotion of water quality and significant reduction of coliform along the sewage effluent gradient.

  10. Raising the Alarmone: Within-Host Evolution of Antibiotic-Tolerant Enterococcus faecium

    Science.gov (United States)

    2017-01-01

    ABSTRACT Enterococci are ancient commensal bacteria that recently emerged as leading causes of antibiotic-resistant, hospital-acquired infection. Vancomycin-resistant enterococci (VRE) epitomize why drug-resistant enterococcal infections are a problem: VRE readily colonize the antibiotic-perturbed gastrointestinal (GI) tract where they amplify to large numbers, and from there, they infect other body sites, including the bloodstream, urinary tract, and surgical wounds. VRE are resistant to many antimicrobials and host defenses, which facilitates establishment at the site of infection and confounds therapeutic clearance. Having evolved to colonize the GI tract, VRE are comparatively ill adapted to the human bloodstream. A recent study by Honsa and colleagues (E. S. Honsa et al., mBio 8:e02124-16, 2017, https://doi.org/10.1128/mBio.02124-16) found that a strain of vancomycin-resistant Enterococcus faecium evolved antibiotic tolerance within the bloodstream of an immunocompromised host by activating the stringent response through mutation of relA. Precisely how VRE colonize and infect and the selective pressures that led to the outgrowth of relA mutants are the subjects of ongoing research. PMID:28223450

  11. Recovery of metallo-tolerant and antibiotic resistant psychrophilic bacteria from Siachen glacier, Pakistan.

    Directory of Open Access Journals (Sweden)

    Muhammad Rafiq

    Full Text Available Cultureable bacterial diversity of previously unexplored Siachen glacier, Pakistan, was studied. Out of 50 isolates 33 (66% were Gram negative and 17 (34% Gram positive. About half of the isolates were pigment producers and were able to grow at 4-37°C. 16S rRNA gene sequences revealed Gram negative bacteria dominated by Proteobacteria (especially γ-proteobacteria and β-proteobacteria and Flavobacteria. The genus Pseudomonas (51.51%, 17 was dominant among γ- proteobacteria. β-proteobacteria constituted 4 (12.12% Alcaligenes and 4 (12.12% Janthinobacterium strains. Among Gram positive bacteria, phylum Actinobacteria, Rhodococcus (23.52%, 4 and Arthrobacter (23.52%, 4 were the dominating genra. Other bacteria belonged to Phylum Firmicutes with representative genus Carnobacterium (11.76%, 2 and 4 isolates represented 4 genera Bacillus, Lysinibacillus, Staphylococcus and Planomicrobium. Most of the Gram negative bacteria were moderate halophiles, while most of the Gram positives were extreme halophiles and were able to grow up to 6.12 M of NaCl. More than 2/3 of the isolates showed antimicrobial activity against multidrug resistant S. aureus, E. coli, Klebsiella pneumonia, Enterococcus faecium, Candida albicans, Aspergillus flavus and Aspergillus fumigatus and ATCC strains. Gram positive bacteria (94.11% were more resistant to heavy metals as compared to Gram negative (78.79% and showed maximum tolerance against iron and least tolerance against mercury.

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  13. Correlation of Frequency of Pseudomonas Aeruginosa and Exos & Exou Genes and Their Antibiotic Sensitivity Pattern in Specimen Isolated from ICU Ward

    Directory of Open Access Journals (Sweden)

    Mahsa Joodzadeh

    2016-06-01

    Full Text Available Pseudomonas aeruginosa is a cause of nosocomial infections that can be destroyer by antibiotic-resistant strains. This study conducted to determine the antibiotic susceptibility pattern and distribution of exoU and exoS among clinical isolates of P. aeruginosa. Fifty three specimens of tracheal tube were collected from patients who were hospitalized in ICU wards and P. aeruginosa were isolated and identified by phenotypic and molecular methods. Antibiotic resistance performs by disk diffusion and analyzed their virulence factors genes by PCR method. Susceptibility pattern of 53 isolates of P. aeruginosa showed that majority and minority of resistance belong to cefepime (55.4%,and Meropenem (50% Respectively. Twenty four (45.2% isolates were not susceptible to three or more different groups of antibiotics. Forty (71.4% of isolated have had exoSand1(1.8% exoU, 8(15%both of exoS and exoU and the rest being negative for exoS or exoU. Distribution of MDR(resistance to three or more group of antibiotics exoenzymes were shown: exoU(7.5%and exoS(90.5%. According to statistically analysis there were not significant relationship between presence of exo SandexoU and antibiotic resistance.

  14. Transposon mutations in the flagella biosynthetic pathway of the solvent-tolerant Pseudomonas putida S12 result in a decreased expression of solvent efflux genes

    NARCIS (Netherlands)

    Kieboom, J; Bruinenberg, R; Keizer-Gunnink, [No Value; de Bont, JAM

    2001-01-01

    Fourteen solvent-sensitive transposon mutants were generated from the solvent-tolerant Pseudomonas putida strain S12 by applying the TnMOD-KmO mutagenesis system. These mutants were unable to grow in the presence of octanol and toluene. By cloning the region flanking the transposon insertion point a

  15. 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.

  16. Interaction of polycationic antibiotics with Pseudomonas aeruginosa lipopolysaccharide and lipid A studied by using dansyl-polymyxin.

    Science.gov (United States)

    Moore, R A; Bates, N C; Hancock, R E

    1986-01-01

    A fluorescent derivative of polymyxin B (dansyl-polymyxin) was used to study the interaction of polycations with lipopolysaccharide (LPS) and lipid A from Pseudomonas aeruginosa. Dansyl-polymyxin became bound to LPS and lipid A sites, including Mg2+-binding sites, resulting in a 20-fold enhancement of fluorescence. A Hill plot of the binding data showed that the binding of dansyl-polymyxin to LPS was cooperative (n = 1.98) and of high affinity (S0.5 = 0.38 microM). The maximal binding capacity of LPS was approximately four molecules of dansyl-polymyxin per mol of LPS. The dansyl-polymyxin interaction with lipid A displayed similar kinetics (n = 2.26; S0.5 = 0.38 microM), and the maximal binding capacity was approximately 2 mol of dansyl-polymyxin per mol of lipid A. A variety of polycationic compounds, including gentamicin, streptomycin, and polymyxin B, as well as Mg2+, were able to displace dansyl-polymyxin bound to LPS or to lipid A. Marked differences both in terms of the degree of displacement and in terms of the amount of competing polycation required to displace a given amount of dansyl-polymyxin were observed. Addition of excess polymyxin B resulted in displacement of all of the dansyl-polymyxin, demonstrating that only polymyxin-binding sites were being probed. Our data demonstrate that polymyxin B binds to multiple sites on LPS, including sites which bind aminoglycoside antibiotics and other polycationic compounds. PMID:3013085

  17. Tolerance of Escherichia coli to fluoroquinolone antibiotics depends on specific components of the SOS response pathway.

    Science.gov (United States)

    Theodore, Alyssa; Lewis, Kim; Vulic, Marin

    2013-12-01

    Bacteria exposed to bactericidal fluoroquinolone (FQ) antibiotics can survive without becoming genetically resistant. Survival of these phenotypically resistant cells, commonly called "persisters," depends on the SOS gene network. We have examined mutants in all known SOS-regulated genes to identify functions essential for tolerance in Escherichia coli. The absence of DinG and UvrD helicases and the Holliday junction processing enzymes RuvA and RuvB leads to a decrease in survival. Analysis of the respective mutants indicates that, in addition to repair of double-strand breaks, tolerance depends on the repair of collapsed replication forks and stalled transcription complexes. Mutation in recF results in increased survival, which identifies RecAF recombination as a poisoning mechanism not previously linked to FQ lethality. DinG acts upstream of SOS promoting its induction, whereas RuvAB participates in repair only. UvrD directly promotes all repair processes initiated by FQ-induced damage and prevents RecAF-dependent misrepair, making it one of the crucial SOS functions required for tolerance.

  18. Structural Features Governing the Activity of Lactoferricin-Derived Peptides That Act in Synergy with Antibiotics against Pseudomonas aeruginosa In Vitro and In Vivo▿ †

    Science.gov (United States)

    Sánchez-Gómez, Susana; Japelj, Bostjan; Jerala, Roman; Moriyón, Ignacio; Fernández Alonso, Mirian; Leiva, José; Blondelle, Sylvie E.; Andrä, Jörg; Brandenburg, Klaus; Lohner, Karl; Martínez de Tejada, Guillermo

    2011-01-01

    Pseudomonas aeruginosa is naturally resistant to many antibiotics, and infections caused by this organism are a serious threat, especially to hospitalized patients. The intrinsic low permeability of P. aeruginosa to antibiotics results from the coordinated action of several mechanisms, such as the presence of restrictive porins and the expression of multidrug efflux pump systems. Our goal was to develop antimicrobial peptides with an improved bacterial membrane-permeabilizing ability, so that they enhance the antibacterial activity of antibiotics. We carried out a structure activity relationship analysis to investigate the parameters that govern the permeabilizing activity of short (8- to 12-amino-acid) lactoferricin-derived peptides. We used a new class of constitutional and sequence-dependent descriptors called PEDES (peptide descriptors from sequence) that allowed us to predict (Spearman's ρ = 0.74; P < 0.001) the permeabilizing activity of a new peptide generation. To study if peptide-mediated permeabilization could neutralize antibiotic resistance mechanisms, the most potent peptides were combined with antibiotics, and the antimicrobial activities of the combinations were determined on P. aeruginosa strains whose mechanisms of resistance to those antibiotics had been previously characterized. A subinhibitory concentration of compound P2-15 or P2-27 sensitized P. aeruginosa to most classes of antibiotics tested and counteracted several mechanisms of antibiotic resistance, including loss of the OprD porin and overexpression of several multidrug efflux pump systems. Using a mouse model of lethal infection, we demonstrated that whereas P2-15 and erythromycin were unable to protect mice when administered separately, concomitant administration of the compounds afforded long-lasting protection to one-third of the animals. PMID:20956602

  19. Structural features governing the activity of lactoferricin-derived peptides that act in synergy with antibiotics against Pseudomonas aeruginosa in vitro and in vivo.

    Science.gov (United States)

    Sánchez-Gómez, Susana; Japelj, Bostjan; Jerala, Roman; Moriyón, Ignacio; Fernández Alonso, Mirian; Leiva, José; Blondelle, Sylvie E; Andrä, Jörg; Brandenburg, Klaus; Lohner, Karl; Martínez de Tejada, Guillermo

    2011-01-01

    Pseudomonas aeruginosa is naturally resistant to many antibiotics, and infections caused by this organism are a serious threat, especially to hospitalized patients. The intrinsic low permeability of P. aeruginosa to antibiotics results from the coordinated action of several mechanisms, such as the presence of restrictive porins and the expression of multidrug efflux pump systems. Our goal was to develop antimicrobial peptides with an improved bacterial membrane-permeabilizing ability, so that they enhance the antibacterial activity of antibiotics. We carried out a structure activity relationship analysis to investigate the parameters that govern the permeabilizing activity of short (8- to 12-amino-acid) lactoferricin-derived peptides. We used a new class of constitutional and sequence-dependent descriptors called PEDES (peptide descriptors from sequence) that allowed us to predict (Spearman's ρ = 0.74; P < 0.001) the permeabilizing activity of a new peptide generation. To study if peptide-mediated permeabilization could neutralize antibiotic resistance mechanisms, the most potent peptides were combined with antibiotics, and the antimicrobial activities of the combinations were determined on P. aeruginosa strains whose mechanisms of resistance to those antibiotics had been previously characterized. A subinhibitory concentration of compound P2-15 or P2-27 sensitized P. aeruginosa to most classes of antibiotics tested and counteracted several mechanisms of antibiotic resistance, including loss of the OprD porin and overexpression of several multidrug efflux pump systems. Using a mouse model of lethal infection, we demonstrated that whereas P2-15 and erythromycin were unable to protect mice when administered separately, concomitant administration of the compounds afforded long-lasting protection to one-third of the animals.

  20. The Frequency and Antibiotic Resistance of Chromate Tolerating Microorganisms in Qom Industrial wastewater

    Directory of Open Access Journals (Sweden)

    MR Zolfaghary

    2012-07-01

    Full Text Available

    Background and Objectives: Chromium is one of the major sources of environmental pollution and a potent occupational carcinogen. The hexavalent chromium compounds are more toxic than those of trivalent. Recent studies have suggested that reduction of Cr(VI to its lower oxidation states and related free radical reactions play an important role in carcinogenic, genotoxic and immunotoxic effects in human and animals.

     This paper reports occurrence of chromium tolerant and antibiotic resistant organism of four industrial wastewaters including electroplating, textile, galvanization, and dye manufacturing in Qom.

     

    Methods: In this study 241 isolates including 23 gram positive coccus, 3 gram negative bacilli and 215 gram positive bacilli were obtained by using of LB Agar plus determined concentration of potassium chromate.

     

    Results: A gram positive coccus, chromate reducing bacteria strain isolated from effluent of chromo plaiting could tolerate up to 760mM concentration in 34°c and pH=7 within 24h and showed resistance to some antibiotics. Biochemical, physiological, morphological and 16SrRNA tests showed this bacteria belongs to staphylococcus arlettae strain R1-7A.

     

    Conclusion: the result indicates that the indigenous microbial isolates can be useful for hexavalent chromium detoxification of chromium contamination environment and reduction of its pathogenicity and carcinogenicity, on the other hand the control of these bacteria is important from the medical view.

     

  1. Impact of the duration of antibiotics on clinical events in patients with Pseudomonas aeruginosa ventilator-associated pneumonia: study protocol for a randomized controlled study.

    Science.gov (United States)

    Bouglé, Adrien; Foucrier, Arnaud; Dupont, Hervé; Montravers, Philippe; Ouattara, Alexandre; Kalfon, Pierre; Squara, Pierre; Simon, Tabassome; Amour, Julien

    2017-01-23

    Ventilator-associated pneumonia (VAP) accounts for 25% of infections in intensive care units. Compared to a long duration (LD) of antibiotic therapy, a short duration (SD) has a comparable clinical efficacy with less antibiotic use and less multidrug-resistant (MDR) pathogen emergence, with the exception of documented VAP of non-fermenting Gram-negative bacilli (NF-GNB), including Pseudomonas aeruginosa (PA). These results have led the American Thoracic Society to recommend SD therapy for VAP, except for PA-VAP. Thus the beneficial effect of SD therapy in PA-VAP is still a matter of debate. We aimed to assess the non-inferiority of a short duration of antibiotics (8 days) versus prolonged antibiotic therapy (15 days) in PA-VAP. The impact of the duration of antibiotics on clinical events in patients with Pseudomonas aeruginosa ventilator-associated pneumonia (iDIAPASON) trial is a randomized, open-labeled non-inferiority controlled trial, conducted in 34 French intensive care units (ICUs), comparing two groups of patients with PA-VAP according to the duration (8 days or 15 days) of effective antibiotic therapy against PA. The primary outcome is a composite endpoint combining day 90 mortality and PA-VAP recurrence rate during hospitalization in the ICU. Furthermore, durations of mechanical ventilation and hospitalization, as well as number and types of extrapulmonary infections or acquisition of MDR pathogens during the hospitalization in the ICU will be recorded. Recurrence with predefined criteria (clinical suspicion of VAP associated with a positive quantitative culture of a respiratory sample) will be evaluated by two independent experts. Demonstrating that an SD (8 days) versus LD (15 days) therapy strategy in PA-VAP treatment is safe and not associated with an increased mortality or recurrence rate could lead to a change in practices and guidelines in the management of antibiotic therapy of this frequent ICU complication. This strategy could lead to

  2. The change of antibiotic resistance profiles over the years in Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from intensive care units

    Directory of Open Access Journals (Sweden)

    M. Cem Şirin

    2015-09-01

    Full Text Available Objective: The aim of this study was to determine the antibiotic resistance profiles of Pseudomonas aeruginosa and Acinetobacter baumannii strains isolated from patients in our hospital intensive care units (ICUs between the years 2011-2014 and to investigate the changes of these profiles over the years. Methods: Identification and antibiotic susceptibility testing of the strains were performed by automated system. Cefoperazone-sulbactam and tigecycline susceptibility was determined by disk diffusion method. Imipenem, meropenem and colistin resistance was confirmed by E-test method. Chi-square and Fisher's exact test were used to compare the antibiotic susceptibilities statistically. Results: The highest resistance rates were determined for imipenem (50.2%, meropenem (51.9% and piperacillin-tazobactam (64.0% in P. aeruginosa strains (n=722. The changes in the rates of antibiotic resistance were not statistically significant in P. aeruginosa strains between the years 2011 and 2014. The decrease in gentamicin, amikacin and trimethoprim-sulfamethoxazole resistance and the increase in cefoperazone-sulbactam and tigecycline resistance was found to be statistically significant in A. baumannii strains (n=1044 between the years 2011 and 2014. The increase in imipenem and meropenem resistance was found to be statistically significant between the years 2012 and 2013. Piperacillin-tazobactam, ceftazidime, cefepime, imipenem and meropenem resistances in A. baumannii strains were found to be over 95% in all the years. Colistin was found to be the most effective antimicrobial agent for both bacteria. Conclusion: The determination of considerably high antibiotic resistance rates in P. aeruginosa and A. baumannii strains isolated from our hospital ICUs has indicated that rational antibiotic use policies and more effective infection control programs should be applied along with monitoring the antibiotic susceptibility profiles constantly. J Clin Exp Invest 2015

  3. Interpreting phenotypic antibiotic tolerance and persister cells as evolution via epigenetic inheritance.

    Science.gov (United States)

    Day, Troy

    2016-04-01

    Epigenetic inheritance is the transmission of nongenetic material such as gene expression levels, RNA and other biomolecules from parents to offspring. There is a growing realization that such forms of inheritance can play an important role in evolution. Bacteria represent a prime example of epigenetic inheritance because a large array of cellular components is transmitted to offspring, in addition to genetic material. Interestingly, there is an extensive and growing empirical literature showing that many bacteria can form 'persister' cells that are phenotypically resistant or tolerant to antibiotics, but most of these results are not interpreted within the context of epigenetic inheritance. Instead, persister cells are usually viewed as a genetically encoded bet-hedging strategy that has evolved in response to a fluctuating environment. Here I show, using a relatively simple model, that many of these empirical findings can be more simply understood as arising from a combination of epigenetic inheritance and cellular noise. I therefore suggest that phenotypic drug tolerance in bacteria might represent one of the best-studied examples of evolution under epigenetic inheritance. © 2016 John Wiley & Sons Ltd.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. 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

  6. 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

  7. Pigments influence the tolerance of Pseudomonas aeruginosa PAO1 to photodynamically induced oxidative stress

    DEFF Research Database (Denmark)

    Orlandi, Viviana T; Bolognese, Fabrizio; Chiodaroli, Luca

    2015-01-01

    by exogenous photosensitizers and visible light. To evaluate whether P. aeruginosa pigments can contribute to its relative tolerance to PDT, we analysed the response to this treatment of isogenic transposon mutants of P. aeruginosa PAO1 with altered pigmentation. In general, in the presence of pigments...

  8. A New Twist to the Kirby-Bauer Antibiotic Susceptibility Test Activity?Increasing Antibiotic Sensitivity of Pseudomonas fluorescens through Thermal Stress

    OpenAIRE

    Gerbig, Donald G.; Engohang-Ndong, Jean; Aubihl, Heather

    2013-01-01

    Antibiotic sensitivity and the effect of temperature on microbial growth are two standard laboratory activities found in most microbial laboratory manuals. We have found a novel way to combine the two activities to demonstrate how temperature can influence antibiotic sensitivity using a standard incubator in instructional laboratory settings. This activity reinforces the important concepts of microbial growth and temperature along with Kirby-Bauer antibiotic susceptibility testing. We found t...

  9. Prevalence of Multiple Antibiotics Resistant (MAR) Pseudomonas Species in the Final Effluents of Three Municipal Wastewater Treatment Facilities in South Africa

    Science.gov (United States)

    Odjadjare, Emmanuel E.; Igbinosa, Etinosa O.; Mordi, Raphael; Igere, Bright; Igeleke, Clara L.; Okoh, Anthony I.

    2012-01-01

    The final effluents of three (Alice, Dimbaza, and East London) wastewater treatment plants (WWTPs) were evaluated to determine their physicochemical quality and prevalence of multiple antibiotics resistant (MAR) Pseudomonas species, between August 2007 and July 2008. The annual mean total Pseudomonas count (TPC) was 1.20 × 104 (cfu/100 mL), 1.08 × 104 (cfu/100 mL), and 2.66 × 104 (cfu/100 mL), for the Alice, Dimbaza, and East London WWTPs respectively. The effluents were generally compliant with recommended limits for pH, temperature, TDS, DO, nitrite and nitrate; but fell short of target standards for turbidity, COD, and phosphate. The tested isolates were highly sensitive to gentamicin (100%), ofloxacin (100%), clindamycin (90%), erythromycin (90%) and nitrofurantoin (80%); whereas high resistance was observed against the penicillins (90–100%), rifampin (90%), sulphamethoxazole (90%) and the cephems (70%). MAR index ranged between 0.26 and 0.58. The study demonstrated that MAR Pseudomonas species were quite prevalent in the final effluents of WWTPs in South Africa; and this can lead to serious health risk for communities that depend on the effluent-receiving waters for sundry purposes. PMID:22829792

  10. [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.

  11. Pseudomonas aeruginosa tolerance to tobramycin, hydrogen peroxide and polymorphonuclear leukocytes is quorum-sensing dependent

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, P.O.; Burmolle, M.

    2005-01-01

    to otherwise lethal doses of antibiotics and are protected from bactericidal activity of polymorphonuclear leukocytes (PMNs). P. aeruginosa controls the expression of many of its virulence factors by means of a cell-cell communication system termed quorum sensing (QS). In the present report it is demonstrated...... that biofilm bacteria in which QS is blocked either by mutation or by administration of QS inhibitory drugs are sensitive to treatment with tobramycin and H2O2, and are readily phagocytosed by PMNs, in contrast to bacteria with functional QS systems. In contrast to the wild-type, QS-deficient biofilms led...... to an immediate respiratory-burst activation of the PMNs in vitro. In vivo QS-deficient mutants provoked a higher degree of inflammation. It is suggested that quorum signals and QS-inhibitory drugs play direct and opposite roles in this process. Consequently, the faster and highly efficient clearance of QS-deficient...

  12. Bistable expression of virulence genes in salmonella leads to the formation of an antibiotic-tolerant subpopulation.

    Directory of Open Access Journals (Sweden)

    Markus Arnoldini

    2014-08-01

    Full Text Available Phenotypic heterogeneity can confer clonal groups of organisms with new functionality. A paradigmatic example is the bistable expression of virulence genes in Salmonella typhimurium, which leads to phenotypically virulent and phenotypically avirulent subpopulations. The two subpopulations have been shown to divide labor during S. typhimurium infections. Here, we show that heterogeneous virulence gene expression in this organism also promotes survival against exposure to antibiotics through a bet-hedging mechanism. Using microfluidic devices in combination with fluorescence time-lapse microscopy and quantitative image analysis, we analyzed the expression of virulence genes at the single cell level and related it to survival when exposed to antibiotics. We found that, across different types of antibiotics and under concentrations that are clinically relevant, the subpopulation of bacterial cells that express virulence genes shows increased survival after exposure to antibiotics. Intriguingly, there is an interplay between the two consequences of phenotypic heterogeneity. The bet-hedging effect that arises through heterogeneity in virulence gene expression can protect clonal populations against avirulent mutants that exploit and subvert the division of labor within these populations. We conclude that bet-hedging and the division of labor can arise through variation in a single trait and interact with each other. This reveals a new degree of functional complexity of phenotypic heterogeneity. In addition, our results suggest a general principle of how pathogens can evade antibiotics: Expression of virulence factors often entails metabolic costs and the resulting growth retardation could generally increase tolerance against antibiotics and thus compromise treatment.

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

    Science.gov (United States)

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

    2012-06-01

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

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

    DEFF Research Database (Denmark)

    Kolpen, Mette; Mousavi, Nabi; Sams, Thomas

    2016-01-01

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

  15. 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...

  16. Interspecific differences in growth response and tolerance to the antibiotic sulfadiazine in ten clonal wetland plants in South China.

    Science.gov (United States)

    Chen, Jinfeng; Xu, Huilian; Sun, Yingbo; Huang, Lili; Zhang, Peixia; Zou, Chunping; Yu, Bo; Zhu, Genfa; Zhao, Chaoyi

    2016-02-01

    Pollution caused by residual antibiotics is a worldwide environmental issue. Antibiotic residues often occur in aquatic ecosystems, posing threats to the health of aquatic organisms. The effects of antibiotic residues on the growth of crop plants and on human health are reasonably well known. However, less is known about antibiotic effects on wetland plants. Therefore, we studied the response and tolerance of ten clonal wetland plants grown in soil spiked with sulfadiazine at 10 mg kg(-1) (an environmentally relevant concentration) and 100 mg kg(-1). At 10 mg kg(-1), ramet number was the least affected trait, while root number was the most affected among plant species. Plant shoot and total biomass were reduced in all species except in Cyperus malaccensis var. brevifolius and Panicum repens. Chlorophyll content was reduced in Alocasia macrorrhiza, Saururus chinensis, and Commelina diffusa. In general, Panicum paludosum and C. malaccensis var. brevifolius showed the least reduction of growth parameters, whereas growth of both A. macrorrhiza and S. chinensis was severely reduced. At 100 mg kg(-1), negative responses occurred in all species. Comprehensive tolerance analysis revealed that P. paludosum and C. malaccensis var. brevifolius were the species most resistant to sulfadiazine. These species are potential candidates for sulfadiazine polluted wetland restoration. A. macrorrhiza and S. chinensis were the most susceptible species and they should be protected from sulfadiazine pollution. Relative plant shoot biomass and height were the most useful indicators for evaluating plant tolerance to sulfadiazine. Plant tolerance to sulfadiazine was associated with the differences of plants in height and shoot biomass. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Augmented effect of early antibiotic treatment in mice with experimental lung infections due to sequentially adapted mucoid strains of Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    van Gennip, M; Moser, Claus; Christensen, Louise D

    2009-01-01

    : A significant reduction in the number of bacteria was observed when initiating treatment 1 h post-infection compared with initiating treatment after 24 h, although the latest isolate avoided complete clearance. Early antibiotic treatment directed at the mucoid phenotype in mice also reduced the inflammation and......Background: Effects of treatment with tobramycin initiated 1 or 24 h post-infection were investigated in a new version of a pulmonary infection model in mice. The model reflects the differentiated behaviour of Pseudomonas aeruginosa mucoid strains isolated from the lungs of one chronically infected......, histopathology, and measurement of granulocyte colony-stimulating factor (G-CSF) and macrophage inflammatory protein 2 (MIP-2). Results: There was a significant reduction of bacteria when comparing treatment initiated 1 h post-infection with treatment initiated after 24 h for isolates 1997 and 2003. Treatment...

  18. Successful control of resistance in Pseudomonas aeruginosa using antibiotic stewardship and infection control programs at a Chinese university hospital: a 6-year prospective study

    Directory of Open Access Journals (Sweden)

    Liu L

    2018-05-01

    Full Text Available Lei Liu,1 Bin Liu,1 Yu Li,2 Wei Zhang1 1Department of Respiratory Medicine, The First Affiliated Hospital of Harbin Medical University, 2Department of Respiratory Medicine, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, People’s Republic of China Objective: Pseudomonas aeruginosa is emerging as a highly multidrug-resistant (MDR nosocomial pathogen. Data on the efficacy of infection control measures in endemic situations are lacking. We investigated the effect of antimicrobial stewardship (AMS and infection control programs (ICPs in controlling the resistance of P. aeruginosa at a tertiary hospital center.Methods: Susceptibility and resistance were investigated using broth microdilution, as per the guidelines of the Clinical and Laboratory Standards Institute. Antibiotic use was restricted through AMS, which included a classification management system for antibiotic use. The ICPs included environmental cleaning and disinfection, hand hygiene, active surveillance of P. aeruginosa, and education about infection control.Results: A total of 2,241 P. aeruginosa isolates were evaluated between 2012 and 2017. Sensitivity and resistance of the isolates to the antipseudomonal antimicrobials colistin and tigecycline were stable. The sensitivity and resistance to other antipseudomonal antimicrobials improved after 2014, after the AMS and ICPs were implemented in 2013. The use of alcohol-based hand gel significantly increased from 0.6 to 10.9 L per 1,000 patient-days (PD during the study period (P=0.005. The incidence rates of extensively drug-resistant (XDR and MDR P. aeruginosa showed a sustained decrease from 2013 (4.9 and 22% to 2017 (1 and 15%, respectively. The yearly consumption of antimicrobial agents also showed a sustained and significant decrease from 45 defined daily doses (DDDs per 1,000 PD to 38.15 DDDs per 1,000 PD (P=0.04. A significant correlation was found between the incidence rate of MDR P. aeruginosa and the

  19. Tolerance of Norway spruce (Picea abies [L.] Karst.) embryogenic tissue to penicillin, carbapenem and aminoglycoside antibiotics

    Czech Academy of Sciences Publication Activity Database

    Malá, J.; Pavingerová, Daniela; Cvrčková, H.; Bříza, Jindřich; Dostál, J.; Šíma, P.

    2009-01-01

    Roč. 55, č. 4 (2009), s. 156-161 ISSN 1212-4834 R&D Projects: GA MZe QH71290 Institutional research plan: CEZ:AV0Z50510513 Keywords : somatic embryogenesis * Norway spruce * penicillin antibiotics * Agrobacterium tumefaciens * carbapenem antibiotics Subject RIV: EB - Genetics ; Molecular Biology

  20. Antibiotic resistance in Pseudomonas aeruginosa strains with increased mutation frequency due to inactivation of the DNA oxidative repair system

    DEFF Research Database (Denmark)

    Mandsberg, Lotte F; Ciofu, Oana; Kirkby, N

    2009-01-01

    ,8-dihydro-8-oxodeoxyguanosine) than PAO1 after exposure to PMNs, and they developed resistance to antibiotics more frequently. The mechanisms of resistance were increased β-lactamase production and overexpression of the MexCD-OprJ efflux-pump. Mutations in either the mutT or the mutY gene were found...... in resistant HP clinical isolates from patients with CF, and complementation with wild-type genes reverted the phenotype. In conclusion, oxidative stress might be involved in the development of resistance to antibiotics. We therefore suggest the possible use of antioxidants for CF patients to prevent...

  1. Development of antibiotic resistance in Pseudomonas aeruginosa during two decades of antipseudomonal treatment at the Danish CF Center

    DEFF Research Database (Denmark)

    Ciofu, O; Giwercman, B; Pedersen, S S

    1994-01-01

    resistance in P. aeruginosa strains isolated from Danish CF patients over a period of 18 years by testing the in vitro efficacy of carbenicillin, piperacillin, ceftazidime, tobramycin and ciprofloxacin against P. aeruginosa strains collected in 1973 (51 strains), 1980 (80 strains), 1985 (58 strains...... was found between the MIC and the number of antipseudomonal courses of antibiotics. The proportion of resistant in vivo selected P. aeruginosa strains, presumed to be stably derepressed producers of chromosomal beta-lactamase, also increased significantly during the period studied. Our results confirm...... that the beta-lactamase production is an important mechanism of antibiotic resistance in P. aeruginosa....

  2. 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.

  3. Transcriptional profiles of pulmonary innate immune responses to isogenic antibiotic-susceptible and multidrug-resistant Pseudomonas aeruginosa.

    Science.gov (United States)

    Tam, Vincent H; Pérez, Cynthia; Ledesma, Kimberly R; Lewis, Russell E

    2018-04-01

    The virulence of an isogenic pair of Pseudomonas aeruginosa strains was studied under similar experimental conditions in two animal infection models. The time to death was significantly longer for the multidrug resistant (MDR) than the wild-type strain. The transcriptional profiles of 84 innate immune response genes in the lungs of immune competent Balb/C mice were further compared. Significantly weaker expression of genes involved in production of soluble pattern recognition receptor and complement were observed in animals infected with the MDR strain. Altered patterns of innate immune system activation may explain the attenuated virulence in MDR bacteria. © 2018 The Societies and John Wiley & Sons Australia, Ltd.

  4. Garlic as an inhibitor of Pseudomonas aeruginosa quorum sensing in cystic fibrosis--a pilot randomized controlled trial

    DEFF Research Database (Denmark)

    Smyth, Alan R; Cifelli, Paramita M; Ortori, Catharine A

    2010-01-01

    Pseudomonas aeruginosa forms biofilms in the cystic fibrosis lung. Quorum sensing (QS) controls biofilm maturation, immune evasion, antibiotic tolerance and virulence factor production. Garlic shows QS inhibitory activity in vitro and in animal models. We report the first clinical trial in man of...

  5. The ABC of Biofilm Drug Tolerance: the MerR-Like Regulator BrlR Is an Activator of ABC Transport Systems, with PA1874-77 Contributing to the Tolerance of Pseudomonas aeruginosa Biofilms to Tobramycin.

    Science.gov (United States)

    Poudyal, Bandita; Sauer, Karin

    2018-02-01

    A hallmark of biofilms is their tolerance to killing by antimicrobial agents. In Pseudomonas aeruginosa , biofilm drug tolerance requires the c-di-GMP-responsive MerR transcriptional regulator BrlR. However, the mechanism by which BrlR mediates biofilm drug tolerance has not been elucidated. Here, we demonstrate that BrlR activates the expression of at least 7 ABC transport systems, including the PA1874-PA1875-PA1876-PA1877 (PA1874-77) operon, with chromatin immunoprecipitation and DNA binding assays confirming BrlR binding to the promoter region of PA1874-77. Insertional inactivation of the 7 ABC transport systems rendered P. aeruginosa PAO1 biofilms susceptible to tobramycin or norfloxacin. Susceptibility was linked to drug accumulation, with BrlR contributing to norfloxacin accumulation in a manner dependent on multidrug efflux pumps and the PA1874-77 ABC transport system. Inactivation of the respective ABC transport system, furthermore, eliminated the recalcitrance of biofilms to killing by tobramycin but not norfloxacin, indicating that drug accumulation is not linked to biofilm drug tolerance. Our findings indicate for the first time that BrlR, a MerR-type transcriptional activator, activates genes encoding several ABC transport systems, in addition to multiple multidrug efflux pump genes. Moreover, our data confirm a BrlR target contributing to drug tolerance, likely countering the prevailing dogma that biofilm tolerance arises from a multiplicity of factors. Copyright © 2018 American Society for Microbiology.

  6. Antibiotic combination therapy can select for broad-spectrum multidrug resistance in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Vestergaard, Martin; Paulander, Wilhelm; Marvig, Rasmus L.

    2016-01-01

    with the resistance evolved after single-drug exposure. Combination therapy selected for mutants that displayed broad-spectrum resistance, and a major resistance mechanism was mutational inactivation of the repressor gene mexR that regulates the multidrug efflux operon mexAB–oprM. Deregulation of this operon led...... to a broad-spectrum resistance phenotype that decreased susceptibility to the combination of drugs applied during selection as well as to unrelated antibiotic classes. Mutants isolated after single-drug exposure displayed narrow-spectrum resistance and carried mutations in the MexCD–OprJ efflux pump...... regulator gene nfxB conferring ciprofloxacin resistance, or in the gene encoding the non-essential penicillin-binding protein DacB conferring ceftazidime resistance. Reconstruction of resistance mutations by allelic replacement and in vitro fitness assays revealed that in contrast to single antibiotic use...

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Inhaled antibiotics for the treatment of chronic Pseudomonas aeruginosa infection in cystic fibrosis patients: challenges to treatment adherence and strategies to improve outcomes

    Directory of Open Access Journals (Sweden)

    Bodnár R

    2016-02-01

    Full Text Available Réka Bodnár,1,2 Ágnes Mészáros,2 Máté Oláh,2 Tamás Ágh3 1Department of Pediatric Pulmonology, Heim Pál Children’s Hospital, Budapest, Hungary; 2University Pharmacy Department of Pharmacy Administration, Semmelweis University, Budapest, Hungary; 3Syreon Research Institute, Budapest, Hungary Background: Inhaled antibiotics (ABs are recommended for use in the therapy of chronic Pseudomonas aeruginosa infection in patients with cystic fibrosis (CF. The aim of this systematic literature review was to identify level of adherence to inhaled ABs and to determine predictors and consequences of nonadherence in CF. Methods: A systematic literature search of English-language articles was conducted in April 2015 using Medline and Embase. No publication date limit was applied. The literature screening was conducted by two independent reviewers. All of the included studies were assessed for quality. Results: The search yielded 193 publications, of which ten met the inclusion criteria and underwent data extraction. Seven studies focused on inhaled tobramycin, one on inhaled colistimethate, one on inhaled levofloxacin, and one on inhaled aztreonam lysine. Medication adherence to inhaled ABs was analyzed by pharmacy refill history, daily phone diary, parent and child self-reports, vials counting, or electronic monitoring. In randomized controlled trials (n=3, proportion of adherent patients (>75%–80% of required doses taken ranged from 86% to 97%; in prospective cohort studies (n=3, adherence rates ranged between 36% and 92%, and in retrospective studies (n=4 it ranged between 60% and 70%. The adherence to inhaled ABs in CF was found to be associated with the complexity of treatment, time of drug administration, age of patients, treatment burden (adverse events, taste, and patient satisfaction. Conclusion: The high diversity of adherence data was because of the different study designs (randomized controlled trials vs real-world studies and the lack

  9. Pseudomonas aeruginosa cells adapted to benzalkonium chloride show resistance to other membrane-active agents but not to clinically relevant antibiotics.

    Science.gov (United States)

    Loughlin, M F; Jones, M V; Lambert, P A

    2002-04-01

    Our objective was to determine whether strains of Pseudomonas aeruginosa can adapt to growth in increasing concentrations of the disinfectant benzalkonium chloride (BKC), and whether co-resistance to clinically relevant antimicrobial agents occurs. Attempts were made to determine what phenotypic alterations accompanied resistance and whether these explained the mechanism of resistance. Strains were serially passaged in increasing concentrations of BKC in static nutrient broth cultures. Serotyping and genotyping were used to determine purity of the cultures. Two strains were examined for cross-resistance to other disinfectants and antibiotics by broth dilution MIC determination. Alterations in outer membrane proteins and lipopolysaccharide (LPS) expressed were examined by SDS-PAGE. Cell surface hydrophobicity and charge, uptake of disinfectant and proportion of specific fatty acid content of outer and cytoplasmic membranes were determined. Two P. aeruginosa strains showed a stable increase in resistance to BKC. Co-resistance to other quaternary ammonium compounds was observed in both strains; chloramphenicol and polymyxin B resistance were observed in one and a reduction in resistance to tobramycin observed in the other. However, no increased resistance to other biocides (chlorhexidine, triclosan, thymol) or antibiotics (ceftazidime, imipenem, ciprofloxacin, tobramycin) was detected. Characteristics accompanying resistance included alterations in outer membrane proteins, uptake of BKC, cell surface charge and hydrophobicity, and fatty acid content of the cytoplasmic membrane, although no evidence was found for alterations in LPS. Each of the two strains had different alterations in phenotype, indicating that such adaptation is unique to each strain of P. aeruginosa and does not result from a single mechanism shared by the whole species.

  10. Prevalence and antibiotic resistance of Pseudomonas aeruginosa in water samples in central Italy and molecular characterization of oprD in imipenem resistant isolates.

    Science.gov (United States)

    Schiavano, Giuditta Fiorella; Carloni, Elisa; Andreoni, Francesca; Magi, Silvia; Chironna, Maria; Brandi, Giorgio; Amagliani, Giulia

    2017-01-01

    This study aimed to analyse the prevalence, antibiotic resistance and genetic relatedness of P. aeruginosa isolates obtained from potable and recreational water samples (n. 8,351) collected from different settings (swimming pools, n. 207; healthcare facilities, n 1,684; accommodation facilities, n. 1,518; municipal waterworks, n. 4,500; residential buildings, n. 235). Possible mechanisms underlying resistance to imipenem, with particular focus on those involving oprD-based uptake, were also explored. Isolation and identification of Pseudomonas aeruginosa was performed according to the standardized procedure UNI EN ISO 16266:2008 followed by PCR confirmation. Antibiotic Susceptibility testing was conducted according to EUCAST standardized disk diffusion method. Genetic relatedness of strains was carried out by RAPD. The sequence of the oprD gene was analyzed by standard method. Fifty-three samples (0.63%) were positive for P. aeruginosa, of which 10/207 (4.83%) were from swimming pools. Five isolates (9.43%) were resistant to imipenem, one to Ticarcillin + Clavulanate, one to both Piperacillin and Ticarcillin + Clavulanate. The highest isolation rate of imipenem resistant P. aeruginosa was observed in swimming pool water. Identical RAPD profiles were found in isolates from the same location in the same year or even in different years. Imipenem resistant strains were identified as carbapenemase-negative and resistance has been associated with inactivating mutations within the oprD gene, with a concomitant loss of porin. RAPD results proved that a water system can remain colonized by one strain for long periods and the contamination may be difficult to eradicate. This study has revealed the presence of P. aeruginosa in different water samples, including resistant strains, especially in swimming pools, and confirmed the role of porins as a contributing factor in carbapenem resistance in Gram-negative bacteria.

  11. Diagnostic multiplex polymerase chain reaction assay for the identification of Pseudomonas aeruginosa from the skin biopsy specimens in burn wound infections and detection of antibiotic susceptibility

    International Nuclear Information System (INIS)

    Mashouf, Rasoul Y.; Farahani, Hadi S.; Zamani, A.

    2008-01-01

    Objective was to identify Pseudomonas aeruginosa (P. aeruginosa) from the skin biopsy specimens in burn wound infections by multiplex polymerase chain reaction (M-PCR) and detection of antimicrobial susceptibility of isolates from culture. We conducted the cross-sectional study in 140 patients with wound infections who admitted to referral burn center of Motahari, Tehran, Iran, during a 12-month period from 2005-2006. Skin biopsy specimens were aseptically taken from each patient, one for PCR and one for bacterial culture. A M-PCR test based on simultaneous amplification of 2 lipoprotein genes: oprI and oprL, was used to directly detect fluorescent pseudomonades and P. aeruginosa in skin biopsy specimens. The susceptibility of P. aeruginosa isolates to 16 antibiotics was determined using the disc diffusion method. Out of 140 biopsy specimens, M-PCR detected 66 (47.2%) isolates, while culture detected 57 (40.7%) isolates as P. aeruginosa. Positive results for both genes which observed only for P. aeruginosa, while only one gene, oprI, was amplified from other fluorescent pseudomonades (n=12) and all other bacterial tested (n=62) were negative by the amplification test. The most effective antibiotics against isolate of P. aeruginosa were cefepime (79%), azetreonam (76%), ticarcillin-clavulanic acid (68%), tobramycin (62%) and amikacin (61%). Multiplex PCR assay appears promising for the rapid and sensitive detection of P. aeruginosa from the burned skin biopsy specimens. Simultaneous amplification of 2 lipoprotein genes: oprI and oprL could detect P. aeruginosa and oprI gene only for other fluorescent pseudomonades. (author)

  12. 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...

  13. Resistance of Bacteria Isolated from Otamiri River to Heavy Metals and Some Selected Antibiotics

    OpenAIRE

    I.C. Mgbemena; J.C. Nnokwe; L.A. Adjeroh; N.N. Onyemekara

    2012-01-01

    This study is aimed at determining the resistance of bacteria to heavy metals and some antibiotics. The ability of aquatic bacteria isolates from Otamiri River at Ihiagwa in Owerri North, Imo State to tolerate or resist the presence of certain selected heavy metals: Pb+, Zn2+ and Fe2+ and some antibiotics was investigated. Identification tests for the bacteria isolates from Otamiri River revealed them to belong to the genera Pseudomonas, Aeromonas, Bacillus, Escherichia, Micrococcus and Prote...

  14. Bile tolerance and its effect on antibiotic susceptibility of probiotic Lactobacillus candidates.

    Science.gov (United States)

    Hyacinta, Májeková; Hana, Kiňová Sepová; Andrea, Bilková; Barbora, Čisárová

    2015-05-01

    Before use in practice, it is necessary to precisely identify and characterize a new probiotic candidate. Eight animal lactobacilli and collection strain Lactobacillus reuteri CCM 3625 were studied from the point of saccharide fermentation profiles, bile salt resistance, antibiogram profiles, and influence of bile on sensitivity to antibiotics. Studied lactobacilli differed in their sugar fermentation ability determined by API 50CHL and their identification based on these profiles did not correspond with molecular-biological one in most cases. Survival of strains Lactobacillus murinus C and L. reuteri KO4b was not affected by presence of bile. The resistance of genus Lactobacillus to vancomycin and quinolones (ofloxacin, ciprofloxacin) was confirmed in all strains tested. This study provides the new information about oxgall (0.5 and 1 %) effect on the lactobacilli antibiotic susceptibility. Antibiotic profiles were not noticeably affected, and both bile concentrations tested had comparable impact on the lactobacilli antibiotic sensitivity. Interesting change was noticed in L. murinus C, where the resistance to cephalosporins was reverted to susceptibility. Similarly, susceptibility of L. reuteri E to ceftazidime arose after incubation in both concentration of bile. After influence of 1 % bile, Lactobacillus mucosae D lost its resistance to gentamicin. On the base of gained outcomes, the best probiotic properties manifested L. reuteri KO4b, Lactobacillus plantarum KG4, and L. reuteri E due to their survival in the presence of bile.

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

    DEFF Research Database (Denmark)

    Wang, Hengzhuang; Ciofu, Oana; Yang, Liang

    2013-01-01

    the role of beta-lactamase in the pharmacokinetics (PK) and pharmacodynamics (PD) of ceftazidime and imipenem on P. aeruginosa biofilms. P. aeruginosa PAO1 and its corresponding beta-lactamase-overproducing mutant, PA Delta DDh2Dh3, were used in this study. Biofilms of these two strains in flow chambers......, microtiter plates, and on alginate beads were treated with different concentrations of ceftazidime and imipenem. The kinetics of antibiotics on the biofilms was investigated in vitro by time-kill methods. Time-dependent killing of ceftazidime was observed in PAO1 biofilms, but concentration-dependent killing...... activity of ceftazidime was observed for beta-lactamase-overproducing biofilms of P. aeruginosa in all three models. Ceftazidime showed time-dependent killing on planktonic PAO1 and PA Delta DDh2Dh3. This difference is probably due to the special distribution and accumulation in the biofilm matrix of beta...

  16. The impact of ColRS two-component system and TtgABC efflux pump on phenol tolerance of Pseudomonas putida becomes evident only in growing bacteria

    Directory of Open Access Journals (Sweden)

    Kivisaar Maia

    2010-04-01

    Full Text Available Abstract Background We have recently found that Pseudomonas putida deficient in ColRS two-component system is sensitive to phenol and displays a serious defect on solid glucose medium where subpopulation of bacteria lyses. The latter phenotype is significantly enhanced by the presence of phenol in growth medium. Here, we focused on identification of factors affecting phenol tolerance of the colR-deficient P. putida. Results By using transposon mutagenesis approach we identified a set of phenol-tolerant derivatives of colR-deficient strain. Surprisingly, half of independent phenol tolerant clones possessed miniTn5 insertion in the ttgABC operon. However, though inactivation of TtgABC efflux pump significantly enhanced phenol tolerance, it did not affect phenol-enhanced autolysis of the colR mutant on glucose medium indicating that phenol- and glucose-caused stresses experienced by the colR-deficient P. putida are not coupled. Inactivation of TtgABC pump significantly increased the phenol tolerance of the wild-type P. putida as well. Comparison of phenol tolerance of growing versus starving bacteria revealed that both ColRS and TtgABC systems affect phenol tolerance only under growth conditions and not under starvation. Flow cytometry analysis showed that phenol strongly inhibited cell division and to some extent also caused cell membrane permeabilization to propidium iodide. Single cell analysis of populations of the ttgC- and colRttgC-deficient strains revealed that their membrane permeabilization by phenol resembles that of the wild-type and the colR mutant, respectively. However, cell division of P. putida with inactivated TtgABC pump seemed to be less sensitive to phenol than that of the parental strain. At the same time, cell division appeared to be more inhibited in the colR-mutant strain than in the wild-type P. putida. Conclusions ColRS signal system and TtgABC efflux pump are involved in the phenol tolerance of P. putida. However, as

  17. Regulation of Nicotine Tolerance by Quorum Sensing and High Efficiency of Quorum Quenching Under Nicotine Stress in Pseudomonas aeruginosa PAO1

    Directory of Open Access Journals (Sweden)

    Huiming Tang

    2018-03-01

    Full Text Available Quorum sensing (QS regulates the behavior of bacterial populations and promotes their adaptation and survival under stress. As QS is responsible for the virulence of vast majority of bacteria, quorum quenching (QQ, the interruption of QS, has become an attractive therapeutic strategy. However, the role of QS in stress tolerance and the efficiency of QQ under stress in bacteria are seldom explored. In this study, we demonstrated that QS-regulated catalase (CAT expression and biofilm formation help Pseudomonas aeruginosa PAO1 resist nicotine stress. CAT activity and biofilm formation in wild type (WT and ΔrhlR strains are significantly higher than those in the ΔlasR strain. Supplementation of ΔlasI strain with 3OC12-HSL showed similar CAT activity and biofilm formation as those of the WT strain. LasIR circuit rather than RhlIR circuit is vital to nicotine tolerance. Acylase I significantly decreased the production of virulence factors, namely elastase, pyocyanin, and pyoverdine under nicotine stress compared to the levels observed in the absence of nicotine stress. Thus, QQ is more efficient under stress. To our knowledge, this is the first study to report that QS contributes to nicotine tolerance in P. aeruginosa. This work facilitates a better application of QQ for the treatment of bacterial infections, especially under stress.

  18. Regulation of Nicotine Tolerance by Quorum Sensing and High Efficiency of Quorum Quenching Under Nicotine Stress in Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Tang, Huiming; Zhang, Yunyun; Ma, Yifan; Tang, Mengmeng; Shen, Dongsheng; Wang, Meizhen

    2018-01-01

    Quorum sensing (QS) regulates the behavior of bacterial populations and promotes their adaptation and survival under stress. As QS is responsible for the virulence of vast majority of bacteria, quorum quenching (QQ), the interruption of QS, has become an attractive therapeutic strategy. However, the role of QS in stress tolerance and the efficiency of QQ under stress in bacteria are seldom explored. In this study, we demonstrated that QS-regulated catalase (CAT) expression and biofilm formation help Pseudomonas aeruginosa PAO1 resist nicotine stress. CAT activity and biofilm formation in wild type (WT) and Δ rhlR strains are significantly higher than those in the Δ lasR strain. Supplementation of Δ lasI strain with 3OC12-HSL showed similar CAT activity and biofilm formation as those of the WT strain. LasIR circuit rather than RhlIR circuit is vital to nicotine tolerance. Acylase I significantly decreased the production of virulence factors, namely elastase, pyocyanin, and pyoverdine under nicotine stress compared to the levels observed in the absence of nicotine stress. Thus, QQ is more efficient under stress. To our knowledge, this is the first study to report that QS contributes to nicotine tolerance in P. aeruginosa . This work facilitates a better application of QQ for the treatment of bacterial infections, especially under stress.

  19. On the limits of toxicant-induced tolerance testing: cotolerance and response variation of antibiotic effects.

    NARCIS (Netherlands)

    Schmitt, Heike; Martinali, Bennie; Beelen, Patrick van; Seinen, Willem

    2006-01-01

    Pollution-induced community tolerance (PICT) as an ecotoxicological test system has been claimed to detect pollutant effects highly specifically and sensitively. However, the specificity might be limited by the occurrence of cotolerance. Another limitation of the application of any ecotoxicological

  20. The Small Colony Variant Of Listeria Monocytogenes Is More Tolerant To Antibiotics And Grows Better Within Caco-2 Epithelial Cells Than The Wild Type

    DEFF Research Database (Denmark)

    Curtis, Thomas; Gram, Lone; Knudsen, Gitte Maegaard

    2015-01-01

    to sublethal concentration of triclosan, and in this study, we characterized their tolerance to antibiotics and ability to invade and survive in host cells. Results: Complementation assays showed that SCV E18 phenotype is caused by a mutation in the heme biosynthesis pathway. Although no difference in MIC...... intracellular environment....

  1. Interaction networks, ecological stability, and collective antibiotic tolerance in polymicrobial infections

    Science.gov (United States)

    de Vos, Marjon G. J.; Bollenbach, Tobias

    2017-01-01

    Polymicrobial infections constitute small ecosystems that accommodate several bacterial species. Commonly, these bacteria are investigated in isolation. However, it is unknown to what extent the isolates interact and whether their interactions alter bacterial growth and ecosystem resilience in the presence and absence of antibiotics. We quantified the complete ecological interaction network for 72 bacterial isolates collected from 23 individuals diagnosed with polymicrobial urinary tract infections and found that most interactions cluster based on evolutionary relatedness. Statistical network analysis revealed that competitive and cooperative reciprocal interactions are enriched in the global network, while cooperative interactions are depleted in the individual host community networks. A population dynamics model parameterized by our measurements suggests that interactions restrict community stability, explaining the observed species diversity of these communities. We further show that the clinical isolates frequently protect each other from clinically relevant antibiotics. Together, these results highlight that ecological interactions are crucial for the growth and survival of bacteria in polymicrobial infection communities and affect their assembly and resilience. PMID:28923953

  2. Phenotypes of Non-Attached Pseudomonas aeruginosa Aggregates Resemble Surface Attached Biofilm

    DEFF Research Database (Denmark)

    Alhede, Morten; Kragh, Kasper Nørskov; Qvortrup, Klaus

    2011-01-01

    For a chronic infection to be established, bacteria must be able to cope with hostile conditions such as low iron levels, oxidative stress, and clearance by the host defense, as well as antibiotic treatment. It is generally accepted that biofilm formation facilitates tolerance to these adverse......, RT-PCR as well as traditional culturing techniques to study the properties of Pseudomonas aeruginosa aggregates. We found that non-attached aggregates from stationary-phase cultures have comparable growth rates to surface attached biofilms. The growth rate estimations indicated that, independently...... were also found to be strikingly similar to flow-cell biofilms. Our data indicate that the tolerance of both biofilms and non-attached aggregates towards antibiotics is reversible by physical disruption. We provide evidence that the antibiotic tolerance is likely to be dependent on both...

  3. Tolerance

    DEFF Research Database (Denmark)

    Tønder, Lars

    is linked to a different set of circumstances than the ones suggested by existing models in contemporary democratic theory. Reorienting the discussion of tolerance, the book raises the question of how to disclose new possibilities within our given context of affect and perception. Once we move away from......Tolerance: A Sensorial Orientation to Politics is an experiment in re-orientation. The book is based on the wager that tolerance exceeds the more prevalent images of self-restraint and repressive benevolence because neither precludes the possibility of a more “active tolerance” motivated...... by the desire to experiment and to become otherwise. The objective is to discuss what gets lost, conceptually as well as politically, when we neglect the subsistence of active tolerance within other practices of tolerance, and to develop a theory of active tolerance in which tolerance's mobilizing character...

  4. Chemotaxis and degradation of organophosphate compound by a novel moderately thermo-halo tolerant Pseudomonas sp. strain BUR11: evidence for possible existence of two pathways for degradation

    Directory of Open Access Journals (Sweden)

    Santanu Pailan

    2015-11-01

    Full Text Available An organophosphate (OP degrading chemotactic bacterial strain BUR11 isolated from an agricultural field was identified as a member of Pseudomonas genus on the basis of its 16S rRNA gene sequence. The strain could utilize parathion, chlorpyrifos and their major hydrolytic intermediates as sole source of carbon for its growth and exhibited positive chemotactic response towards most of them. Optimum concentration of parathion for its growth was recorded to be 200 ppm and 62% of which was degraded within 96 h at 37 °C. Growth studies indicated the strain to be moderately thermo-halo tolerant in nature. Investigation based on identification of intermediates of parathion degradation by thin layer chromatography (TLC, high performance liquid chromatography (HPLC, gas chromatography (GC and liquid chromatography mass spectrometry (LC-MS/MS provided evidence for possible existence of two pathways. The first pathway proceeds via 4-nitrophenol (4-NP while the second proceeds through formation of 4-aminoparathion (4-APar, 4-aminophenol (4-AP and parabenzoquinone (PBQ. This is the first report of chemotaxis towards organophosphate compound by a thermo-halo tolerant bacterium.

  5. Core Flood study for enhanced oil recovery through ex-situ bioaugmentation with thermo- and halo-tolerant rhamnolipid produced by Pseudomonas aeruginosa NCIM 5514.

    Science.gov (United States)

    Varjani, Sunita J; Upasani, Vivek N

    2016-11-01

    The aim of this work was to study the Microbial Enhanced Oil Recovery (MEOR) employing core field model ex-situ bioaugmenting a thermo- and halo-tolerant rhamnolipid produced by Pseudomonas aeruginosa. Thin Layer Chromatography (TLC) revealed that the biosurfactant produced was rhamnolipid type. Nuclear Magnetic Resonance analysis showed that the purified rhamnolipids comprised two principal rhamnolipid homologues, i.e., Rha-Rha-C10-C14:1 and Rha-C8-C10. The rhamnolipid was stable under wide range of temperature (4°C, 30-100°C), pH (2.0-10.0) and NaCl concentration (0-18%, w/v). Core Flood model was designed for oil recovery operations using rhamnolipid. The oil recovery enhancement over Residual Oil Saturation was 8.82% through ex-situ bioaugmentation with rhamnolipid. The thermal stability of rhamnolipid shows promising scope for its application at conditions where high temperatures prevail in oil recovery processes, whereas its halo-tolerant nature increases its application in marine environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Prophages and growth dynamics confound experimental results with antibiotic-tolerant persister cells

    DEFF Research Database (Denmark)

    Harms, Alexander; Fino, Cinzia; Sørensen, Michael Askvad

    2017-01-01

    the validity of our model of persister formation in a refined assay setup that uses robust culture conditions and unravels the dynamics of persister cells through all bacterial growth stages. Our results confirm the importance of (p)ppGpp and Lon but no longer support a role of TA modules in E. coli persister......) modules. This model found considerable support among researchers studying persisters but also generated controversy as part of recent debates in the field. In this study, we therefore used our previous work as a model to critically examine common experimental procedures to understand and overcome......-tolerant persisters via induction of cryptic prophages. Similarly, the inadvertent infection of mutant strains with bacteriophage φ80, a notorious laboratory contaminant, apparently caused several of the phenotypes that we reported in our previous studies. We therefore reconstructed all infected mutants and probed...

  7. Tolerance

    DEFF Research Database (Denmark)

    Tønder, Lars

    Tolerance: A Sensorial Orientation to Politics is an experiment in re-orientation. The book is based on the wager that tolerance exceeds the more prevalent images of self-restraint and repressive benevolence because neither precludes the possibility of a more “active tolerance” motivated by the d...... these alternatives by returning to the notion of tolerance as the endurance of pain, linking this notion to exemplars and theories relevant to the politics of multiculturalism, religious freedom, and free speech....

  8. Involvement of the TonB system in tolerance to solvents and drugs in Pseudomonas putida DOT-T1E.

    Science.gov (United States)

    Godoy, P; Ramos-González, M I; Ramos, J L

    2001-09-01

    Pseudomonas putida DOT-T1E is able to grow with glucose as the carbon source in liquid medium with 1% (vol/vol) toluene or 17 g of (123 mM) p-hydroxybenzoate (4HBA) per liter. After random mini-Tn5'phoA-Km mutagenesis, we isolated the mutant DOT-T1E-PhoA5, which was more sensitive than the wild type to 4HBA (growth was prevented at 6 g/liter) and toluene (the mutant did not withstand sudden toluene shock). Susceptibility to toluene and 4HBA resulted from the reduced efflux of these compounds from the cell, as revealed by accumulation assays with (14)C-labeled substrates. The mutant was also more susceptible to a number of antibiotics, and its growth in iron-deficient minimal medium was inhibited in the presence of ethylenediamine-di(o-hydroxyphenylacetic acid (EDDHA). Cloning the mutation in the PhoA5 strain and sequencing the region adjacent showed that the mini-Tn5 transposor interrupted the exbD gene, which forms part of the exbBD tonB operon. Complementation by the exbBD and tonB genes cloned in pJB3-Tc restored the wild-type characteristics to the PhoA5 strain.

  9. Antibiotic resistance of bacterial biofilms

    DEFF Research Database (Denmark)

    Hoiby, N.; Bjarnsholt, T.; Givskov, M.

    2010-01-01

    A biofilm is a structured consortium of bacteria embedded in a self-produced polymer matrix consisting of polysaccharide, protein and DNA. Bacterial biofilms cause chronic infections because they show increased tolerance to antibiotics and disinfectant chemicals as well as resisting phagocytosis...... and other components of the body's defence system. The persistence of, for example, staphylococcal infections related to foreign bodies is due to biofilm formation. Likewise, chronic Pseudomonas aeruginosa lung infection in cystic fibrosis patients is caused by biofilm-growing mucoid strains....... Characteristically, gradients of nutrients and oxygen exist from the top to the bottom of biofilms and these gradients are associated with decreased bacterial metabolic activity and increased doubling times of the bacterial cells; it is these more or less dormant cells that are responsible for some of the tolerance...

  10. Homology modeling and docking studies of a Δ9-fatty acid desaturase from a Cold-tolerant Pseudomonas sp. AMS8

    Directory of Open Access Journals (Sweden)

    Lawal Garba

    2018-03-01

    Full Text Available Membrane-bound fatty acid desaturases perform oxygenated desaturation reactions to insert double bonds within fatty acyl chains in regioselective and stereoselective manners. The Δ9-fatty acid desaturase strictly creates the first double bond between C9 and 10 positions of most saturated substrates. As the three-dimensional structures of the bacterial membrane fatty acid desaturases are not available, relevant information about the enzymes are derived from their amino acid sequences, site-directed mutagenesis and domain swapping in similar membrane-bound desaturases. The cold-tolerant Pseudomonas sp. AMS8 was found to produce high amount of monounsaturated fatty acids at low temperature. Subsequently, an active Δ9-fatty acid desaturase was isolated and functionally expressed in Escherichia coli. In this paper we report homology modeling and docking studies of a Δ9-fatty acid desaturase from a Cold-tolerant Pseudomonas sp. AMS8 for the first time to the best of our knowledge. Three dimensional structure of the enzyme was built using MODELLER version 9.18 using a suitable template. The protein model contained the three conserved-histidine residues typical for all membrane-bound desaturase catalytic activity. The structure was subjected to energy minimization and checked for correctness using Ramachandran plots and ERRAT, which showed a good quality model of 91.6 and 65.0%, respectively. The protein model was used to preform MD simulation and docking of palmitic acid using CHARMM36 force field in GROMACS Version 5 and Autodock tool Version 4.2, respectively. The docking simulation with the lowest binding energy, −6.8 kcal/mol had a number of residues in close contact with the docked palmitic acid namely, Ile26, Tyr95, Val179, Gly180, Pro64, Glu203, His34, His206, His71, Arg182, Thr85, Lys98 and His177. Interestingly, among the binding residues are His34, His71 and His206 from the first, second, and third conserved histidine motif, respectively

  11. [Evolution of susceptibility to antibiotics of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumanii, in a University Hospital Center of Beirut between 2005 and 2009].

    Science.gov (United States)

    Hamouche, E; Sarkis, D K

    2012-06-01

    Until recently, multiresistant bacteria were only limited to hospitals. However, they are now responsible for community acquired infections, affecting people who have had no contact with the hospital environment. Several mechanisms are associated with these resistances. The production of betalactamases is however the predominant mechanism and especially the production of extended spectrum beta-lactamases or ESBL by strains of Escherichia coli and Klebsiella pneumoniae, which mediate resistance to third generation cephalosporins and aztreonam (AZT). The association of multiple mechanisms of resistance (efflux pumps, impermeability and enzymatic inactivation) generates multi resistant bacteria such as Pseudomonas aeruginosa MDR and Klebsiella pneumoniae MDR. The aim of the study was to analyze retrospectively the susceptibility to antibiotics of strains of E. coli, K. pneumoniae, P. aeruginosa and A. baumanii isolated from hospitalized and outpatients in a university hospital center of Beirut over a period of five years from 2005 to 2009. Bacterial strains were classified according to their origin (inpatients versus outpatients), their ability to produce or not ESBLs for E. coli and K. pneumonia and if they were MDR for P. aeruginosa and A. baumanii. Antibiotics susceptibilities were retrieved from the informatics database of the hospital. Comparison of susceptibility percentages was done using a unilateral z-test on a computer program. In 2009, 2541 strains of E. coli were isolated, 773 of which or 30.4 % were ESBL producers while 2031 strains were isolated in 2005, of which 361 or 17.8 % were ESBL producers (pproducing strains between 2007 and 2009: 33.4 % versus 30.4 % (p=0.03). Among 560 strains of K. pneumoniae isolated in 2009, 178 strains or 31.8 % were ESBL producers in comparison to 23.7 % of the strains isolated in 2005 (p=0.03). We also noticed a decrease in hospital strains susceptibility to piperacilline-tazobactam (TZP), cefotaxime (CTX

  12. Overexpression of Nictaba-Like Lectin Genes from Glycine max Confers Tolerance towards Pseudomonas syringae Infection, Aphid Infestation and Salt Stress in Transgenic Arabidopsis Plants

    Directory of Open Access Journals (Sweden)

    Sofie Van Holle

    2016-10-01

    Full Text Available Plants have evolved a sophisticated immune system that allows them to recognize invading pathogens by specialized receptors. Carbohydrate-binding proteins or lectins are part of this immune system and especially the lectins that reside in the nucleocytoplasmic compartment are known to be implicated in biotic and abiotic stress responses. The class of Nictaba-like lectins (NLL groups all proteins with homology to the tobacco (Nicotiana tabacum lectin, known as a stress-inducible lectin. Here we focus on two Nictaba homologs from soybean (Glycine max, referred to as GmNLL1 and GmNLL2. Confocal laser scanning microscopy of fusion constructs with the green fluorescent protein either transiently expressed in Nicotiana benthamiana leaves or stably transformed in tobacco BY-2 suspension cells revealed a nucleocytoplasmic localization for the GmNLLs under study. RT-qPCR analysis of the transcript levels for the Nictaba-like lectins in soybean demonstrated that the genes are expressed in several tissues throughout the development of the plant. Furthermore, it was shown that salt treatment, Phytophthora sojae infection and Aphis glycines infestation trigger the expression of particular NLL genes. Stress experiments with Arabidopsis lines overexpressing the NLLs from soybean yielded an enhanced tolerance of the plant towards bacterial infection (Pseudomonas syringae, insect infestation (Myzus persicae and salinity. Our data showed a better performance of the transgenic lines compared to wild type plants, indicating that the NLLs from soybean are implicated in the stress response. These data can help to further elucidate the physiological importance of the Nictaba-like lectins from soybean, which can ultimately lead to the design of crop plants with a better tolerance to changing environmental conditions.

  13. Production of protease and lipase by solvent tolerant Pseudomonas aeruginosa PseA in solid-state fermentation using Jatropha curcas seed cake as substrate.

    Science.gov (United States)

    Mahanta, Nilkamal; Gupta, Anshu; Khare, S K

    2008-04-01

    Deoiled Jatropha seed cake was assessed for its suitability as substrate for enzyme production by solid-state fermentation (SSF). Solvent tolerant Pseudomonas aeruginosa PseA strain previously reported by us was used for fermentation. The seed cake supported good bacterial growth and enzyme production (protease, 1818 U/g of substrate and lipase, 625 U/g of substrate) as evident by its chemical composition. Maximum protease and lipase production was observed at 50% substrate moisture, a growth period of 72 and 120 h, and a substrate pH of 6.0 and 7.0, respectively. Enrichment with maltose as carbon source increased protease and lipase production by 6.3- and 1.6-fold, respectively. Nitrogen supplementation with peptone for protease and NaNO(3) for lipase production also enhanced the enzyme yield reaching 11,376 U protease activity and 1084 U lipase activity per gram of Jatropha seed cake. These results demonstrated viable approach for utilization of this huge biomass by solid-state fermentation for the production of industrial enzymes. This offers significant benefit due to low cost and abundant availability of cake during biodiesel production.

  14. Enhancement of thermo-stability and product tolerance of Pseudomonas putida nitrile hydratase by fusing with self-assembling peptide.

    Science.gov (United States)

    Liu, Yi; Cui, Wenjing; Liu, Zhongmei; Cui, Youtian; Xia, Yuanyuan; Kobayashi, Michihiko; Zhou, Zhemin

    2014-09-01

    Self-assembling amphipathic peptides (SAPs) are the peptides that can spontaneously assemble into ordered nanostructures. It has been reported that the attachment of SAPs to the N- or C-terminus of an enzyme can benefit the thermo-stability of the enzyme. Here, we discovered that the thermo-stability and product tolerance of nitrile hydratase (NHase) were enhanced by fusing with two of the SAPs (EAK16 and ELK16). When the ELK16 was fused to the N-terminus of β-subunit, the resultant NHase (SAP-NHase-2) became an active inclusion body; EAK16 fused NHase in the N-terminus of β-subunit (SAP-NHase-1) and ELK16 fused NHase in the C-terminus of β-subunit (SAP-NHase-10) did not affect NHase solubility. Compared with the deactivation of the wild-type NHase after 30 min incubation at 50°C, SAP-NHase-1, SAP-NHase-2 and SAP-NHase-10 retained 45%, 30% and 50% activity; after treatment in the buffer containing 10% acrylamide, the wild-type retained 30% activity, while SAP-NHase-1, SAP-NHase-2 and SAP-NHase-10 retained 52%, 42% and 55% activity. These SAP-NHases with enhanced thermo-stability and product tolerance would be helpful for further industrial applications of the NHase. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  15. 40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...

    Science.gov (United States)

    2010-07-01

    ... thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens; exemption from the requirement... killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens is exempt from the...

  16. Distributed lags time series analysis versus linear correlation analysis (Pearson's r) in identifying the relationship between antipseudomonal antibiotic consumption and the susceptibility of Pseudomonas aeruginosa isolates in a single Intensive Care Unit of a tertiary hospital.

    Science.gov (United States)

    Erdeljić, Viktorija; Francetić, Igor; Bošnjak, Zrinka; Budimir, Ana; Kalenić, Smilja; Bielen, Luka; Makar-Aušperger, Ksenija; Likić, Robert

    2011-05-01

    The relationship between antibiotic consumption and selection of resistant strains has been studied mainly by employing conventional statistical methods. A time delay in effect must be anticipated and this has rarely been taken into account in previous studies. Therefore, distributed lags time series analysis and simple linear correlation were compared in their ability to evaluate this relationship. Data on monthly antibiotic consumption for ciprofloxacin, piperacillin/tazobactam, carbapenems and cefepime as well as Pseudomonas aeruginosa susceptibility were retrospectively collected for the period April 2006 to July 2007. Using distributed lags analysis, a significant temporal relationship was identified between ciprofloxacin, meropenem and cefepime consumption and the resistance rates of P. aeruginosa isolates to these antibiotics. This effect was lagged for ciprofloxacin and cefepime [1 month (R=0.827, P=0.039) and 2 months (R=0.962, P=0.001), respectively] and was simultaneous for meropenem (lag 0, R=0.876, P=0.002). Furthermore, a significant concomitant effect of meropenem consumption on the appearance of multidrug-resistant P. aeruginosa strains (resistant to three or more representatives of classes of antibiotics) was identified (lag 0, R=0.992, PPearson's correlation coefficient. Correlation coefficient analysis was not able to identify relationships between antibiotic consumption and bacterial resistance when the effect was delayed. These results indicate that the use of diverse statistical methods can yield significantly different results, thus leading to the introduction of possibly inappropriate infection control measures. Copyright © 2010 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

  17. Pseudomonas aeruginosa chromosomal beta-lactamase in patients with cystic fibrosis and chronic lung infection. Mechanism of antibiotic resistance and target of the humoral immune response

    DEFF Research Database (Denmark)

    Ciofu, Oana

    2003-01-01

    the development of resistance to beta-lactam antibiotics and the occurrence of high beta-lactamase producing strains and between the MIC of the beta-lactams and the levels of beta-lactamase expression. Partially derepressed mutants, characterized by high basal levels of beta-lactamase with the possibility...... of induction to even higher levels during treatment with beta-lactam antibiotics, were the most frequent phenotype found among resistant Danish P. aeruginosa CF isolates. We have also shown that the high alginate producing P. aeruginosa isolates, that characterize the chronic lung infection in CF patients......, are more susceptible to antibiotics and produce less beta-lactamase than the non-mucoid paired isolates. We propose that the non-mucoid isolates are exposed to a relatively higher antibiotic pressure than the mucoid isolates and therefore, they become easily antibiotic resistant and in consequence produce...

  18. 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...

  19. Identification of a Signal That Mediates the Crosstalk Between Biosynthetic Gene Clusters for the Antibiotics 2,4-diacetylphloroglucinol and Pyoluteorin in Pseudomonas protegens Pf-5

    Science.gov (United States)

    Pseudomonas protegens Pf-5 produces a broad spectrum of secondary metabolites with anti-microbial activity. The production of two of these metabolites, 2,4-diacetylphloroglucinol (DAPG) and pyoluteorin, is coordinately regulated. Our previous study indicated that phloroglucinol, an intermediate in t...

  20. Co-silencing of tomato S-adenosylhomocysteine hydrolase genes confers increased immunity against Pseudomonas syringae pv. tomato DC3000 and enhanced tolerance to drought stress

    Directory of Open Access Journals (Sweden)

    Li Xiao Hui

    2015-09-01

    Full Text Available S-adenosylhomocysteine hydrolase (SAHH, catalyzing the reversible hydrolysis of S-adenosylhomocysteine to adenosine and homocysteine, is a key enzyme that maintain the cellular methylation potential in all organisms. We report here the biological functions of tomato SlSAHHs in stress response. The tomato genome contains three SlSAHH genes that encode SlSAHH proteins with high level of sequence identity. qRT-PCR analysis revealed that SlSAHHs responded with distinct expression induction patterns to Pseudomonas syringae pv. tomato (Pst DC3000 and Botrytis cinerea as well as to defense signaling hormones such as salicylic acid, jasmonic acid and a precursor of ethylene. Virus-induced gene silencing-based knockdown of individual SlSAHH gene did not affect the growth performance and the response to Pst DC3000. However, co-silencing of three SlSAHH genes using a conserved sequence led to significant inhibition of vegetable growth. The SlSAHH-co-silenced plants displayed increased resistance to Pst DC3000 but did not alter the resistance to B. cinerea. Co-silencing of SlSAHHs resulted in constitutively activated defense responses including elevated SA level, upregulated expression of defense-related and PAMP-triggered immunity marker genes and increased callose deposition and H2O2 accumulation. Furthermore, the SlSAHH-co-silenced plants also exhibited enhanced drought stress tolerance although they had relatively small roots. These data demonstrate that, in addition to the functions in growth and development, SAHHs also play important roles in regulating biotic and abiotic stress responses in plants.

  1. 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...

  2. 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...

  3. Zingerone Suppresses Liver Inflammation Induced by Antibiotic Mediated Endotoxemia through Down Regulating Hepatic mRNA Expression of Inflammatory Markers in Pseudomonas aeruginosa Peritonitis Mouse Model

    OpenAIRE

    Kumar, Lokender; Chhibber, Sanjay; Harjai, Kusum

    2014-01-01

    Antibiotic-induced endotoxin release is associated with high mortality rate even when appropriate antibiotics are used for the treatment of severe infections in intensive care units. Since liver is involved in systemic clearance and detoxification of endotoxin hence it becomes a primary target organ for endotoxin mediated inflammation. Currently available anti-inflammatory drugs give rise to serious side effects. Hence, there is an urgent need for safe and effective anti-inflammatory therapy....

  4. 40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...

    Science.gov (United States)

    2010-07-01

    ... thuringiensis variety San Diego encapsulated into killed Pseudomonas fluorescens; exemption from the requirement... into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas fluorescens is...

  5. Antibiotic Multiresistance Analysis of Mesophilic and Psychrotrophic Pseudomonas spp. Isolated from Goat and Lamb Slaughterhouse Surfaces throughout the Meat Production Process

    OpenAIRE

    Lavilla Lerma, Leyre; Benomar, Nabil; Casado Muñoz, María del Carmen; Gálvez, Antonio; Abriouel, Hikmate

    2014-01-01

    The aim of this study was to investigate the phenotypic and genotypic antibiotic resistance profiles of pseudomonads isolated from surfaces of a goat and lamb slaughterhouse, which were representative of areas that are possible sources of meat contamination. Mesophilic (85 isolates) and psychrotrophic (37 isolates) pseudomonads identified at the species level generally were resistant to sulfamethoxazole, erythromycin, amoxicillin, ampicillin, chloramphenicol, trimethoprim, rifampin, and cefta...

  6. 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...

  7. Pseudomonas - Fact Sheet

    OpenAIRE

    Public Health Agency

    2012-01-01

    Fact sheet on Pseudomonas, including:What is Pseudomonas?What infections does it cause?Who is susceptible to pseudomonas infection?How will I know if I have pseudomonas infection?How can Pseudomonas be prevented from spreading?How can I protect myself from Pseudomonas?How is Pseudomonas infection treated?

  8. Zingerone suppresses liver inflammation induced by antibiotic mediated endotoxemia through down regulating hepatic mRNA expression of inflammatory markers in Pseudomonas aeruginosa peritonitis mouse model.

    Directory of Open Access Journals (Sweden)

    Lokender Kumar

    Full Text Available Antibiotic-induced endotoxin release is associated with high mortality rate even when appropriate antibiotics are used for the treatment of severe infections in intensive care units. Since liver is involved in systemic clearance and detoxification of endotoxin hence it becomes a primary target organ for endotoxin mediated inflammation. Currently available anti-inflammatory drugs give rise to serious side effects. Hence, there is an urgent need for safe and effective anti-inflammatory therapy. It is likely that anti-inflammatory phytochemicals and neutraceutical agents may have the potential to reduce the endotoxin mediated inflammation and complications associated with endotoxin release. Keeping this in mind, the present study was planned to evaluate the hepatoprotective potential of zingerone (active compound of zingiber officinale against liver inflammation induced by antibiotic mediated endotoxemia. The selected antibiotics capable of releasing high content of endotoxin were employed for their in vivo efficacy in P.aeruginosa peritonitis model. Released endotoxin induced inflammation and zingerone as co-anti-inflammatory therapy significantly reduced inflammatory response. Improved liver histology and reduced inflammatory markers MDA, RNI, MPO, tissue damage markers (AST, ALT, ALP and inflammatory cytokines (MIP-2, IL-6 and TNF-α were indicative of therapeutic potential of zingerone. The mechanism of action of zingerone may be related to significant inhibition of the mRNA expression of inflammatory markers (TLR4, RelA, NF-kB2, TNF- α, iNOS, COX-2 indicating that zingerone interferes with cell signalling pathway and suppresses hyper expression of cell signaling molecules of inflammatory pathway. Zingerone therapy significantly protected liver from endotoxin induced inflammatory damage by down regulating biochemical as well as molecular markers of inflammation. In conclusion, this study provides evidence that zingerone is a potent anti

  9. Zingerone suppresses liver inflammation induced by antibiotic mediated endotoxemia through down regulating hepatic mRNA expression of inflammatory markers in Pseudomonas aeruginosa peritonitis mouse model.

    Science.gov (United States)

    Kumar, Lokender; Chhibber, Sanjay; Harjai, Kusum

    2014-01-01

    Antibiotic-induced endotoxin release is associated with high mortality rate even when appropriate antibiotics are used for the treatment of severe infections in intensive care units. Since liver is involved in systemic clearance and detoxification of endotoxin hence it becomes a primary target organ for endotoxin mediated inflammation. Currently available anti-inflammatory drugs give rise to serious side effects. Hence, there is an urgent need for safe and effective anti-inflammatory therapy. It is likely that anti-inflammatory phytochemicals and neutraceutical agents may have the potential to reduce the endotoxin mediated inflammation and complications associated with endotoxin release. Keeping this in mind, the present study was planned to evaluate the hepatoprotective potential of zingerone (active compound of zingiber officinale) against liver inflammation induced by antibiotic mediated endotoxemia. The selected antibiotics capable of releasing high content of endotoxin were employed for their in vivo efficacy in P.aeruginosa peritonitis model. Released endotoxin induced inflammation and zingerone as co-anti-inflammatory therapy significantly reduced inflammatory response. Improved liver histology and reduced inflammatory markers MDA, RNI, MPO, tissue damage markers (AST, ALT, ALP) and inflammatory cytokines (MIP-2, IL-6 and TNF-α) were indicative of therapeutic potential of zingerone. The mechanism of action of zingerone may be related to significant inhibition of the mRNA expression of inflammatory markers (TLR4, RelA, NF-kB2, TNF- α, iNOS, COX-2) indicating that zingerone interferes with cell signalling pathway and suppresses hyper expression of cell signaling molecules of inflammatory pathway. Zingerone therapy significantly protected liver from endotoxin induced inflammatory damage by down regulating biochemical as well as molecular markers of inflammation. In conclusion, this study provides evidence that zingerone is a potent anti

  10. The Widespread Multidrug-Resistant Serotype O12 Pseudomonas aeruginosa Clone Emerged through Concomitant Horizontal Transfer of Serotype Antigen and Antibiotic Resistance Gene Clusters

    DEFF Research Database (Denmark)

    Thrane, Sandra Wingaard; Taylor, Véronique L.; Freschi, Luca

    2015-01-01

    . aeruginosa O12 OSA gene cluster, an antibiotic resistance determinant (gyrAC248T), and other genes that have been transferred between P. aeruginosa strains with distinct core genome architectures. We showed that these genes were likely acquired from an O12 serotype strain that is closely related to P...... in clinical settings and outbreaks. These serotype O12 isolates exhibit high levels of resistance to various classes of antibiotics. Here, we explore how the P. aeruginosa OSA biosynthesis gene clusters evolve in the population by investigating the association between the phylogenetic relationships among 83 P....... aeruginosa strains and their serotypes. While most serotypes were closely linked to the core genome phylogeny, we observed horizontal exchange of OSA biosynthesis genes among phylogenetically distinct P. aeruginosa strains. Specifically, we identified a "serotype island" ranging from 62 kb to 185 kb containing the P...

  11. Subinhibitory Concentrations of Bacteriostatic Antibiotics Induce relA-Dependent and relA-Independent Tolerance to beta-Lactams

    Czech Academy of Sciences Publication Activity Database

    Kudrin, P.; Varik, V.; Oliveira, S. R. A.; Beljantseva, J.; Del Peso Santos, T.; Dzhygyr, I.; Rejman, Dominik; Cava, F.; Tenson, T.; Hauryliuk, V.

    2017-01-01

    Roč. 61, č. 4 (2017), č. článku e02173-16. ISSN 0066-4804 R&D Projects: GA ČR GA15-11711S Institutional support: RVO:61388963 Keywords : beta-lactam * RelA * antibiotics * mupirocin * persistence * ppGpp Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.302, year: 2016 http://aac.asm.org/content/61/4/e02173-16.full

  12. Peripartum Antibiotics Promote Gut Dysbiosis, Loss of Immune Tolerance, and Inflammatory Bowel Disease in Genetically Prone Offspring.

    Science.gov (United States)

    Miyoshi, Jun; Bobe, Alexandria M; Miyoshi, Sawako; Huang, Yong; Hubert, Nathaniel; Delmont, Tom O; Eren, A Murat; Leone, Vanessa; Chang, Eugene B

    2017-07-11

    Factors affecting the developing neonatal gut microbiome and immune networks may increase the risk of developing complex immune disorders such as inflammatory bowel diseases (IBD). In particular, peripartum antibiotics have been suggested as risk factors for human IBD, although direct evidence is lacking. Therefore, we examined the temporal impact of the commonly used antibiotic cefoperazone on both maternal and offspring microbiota when administered to dams during the peripartum period in the IL-10-deficient murine colitis model. By rigorously controlling for cage, gender, generational, and murine pathobiont confounders, we observed that offspring from cefoperazone-exposed dams develop a persistent gut dysbiosis into adulthood associated with skewing of the host immune system and increased susceptibility to spontaneous and chemically dextran sodium sulfate (DSS)-induced colitis. Thus, early life exposure to antibiotic-induced maternal dysbiosis during a critical developmental window for gut microbial assemblage and immune programming elicits a lasting impact of increased IBD risk on genetically susceptible offspring. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  13. Triazole-containing N-acyl homoserine lactones targeting the quorum sensing system in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Hansen, Mette Reimert; Jakobsen, Tim H.; Bang, Claus Gunnar

    2015-01-01

    the pathogenesis and antibiotic tolerance of a bacterial biofilm. To identify the structural elements important for antagonistic or agonistic activity against the Pseudomonas aeruginosa LasR protein, we report the synthesis and screening of new triazole-containing mimics of natural N-acyl homoserine lactones....... A series of azide- and alkyne-containing homoserine lactone building blocks was used to prepare an expanded set of 123 homoserine lactone analogues through a combination of solution- and solid-phase synthesis methods. The resulting compounds were subjected to cell-based quorum sensing screening assays...

  14. Prevalence of metallo-beta-lactamase among Pseudomonas aeruginosa and Acinetobacter baumannii isolated from burn wounds and in vitro activities of antibiotic combinations against these isolates.

    Science.gov (United States)

    Altoparlak, Ulku; Aktas, Ferda; Celebi, Demet; Ozkurt, Zulal; Akcay, Mufide N

    2005-09-01

    The prevalence of metallo-beta-lactamases (MBLs) produced by isolates of Pseudomonas aeruginosa and Acinetobacter baumannii and the activities of various antmicrobial combinations against MBL producer strains were investigated. During the period from June 2003 till July 2004, 120 P. aeruginosa and 9 A. baumannii nonduplicate isolates were obtained from burn wounds. Forty strains (37 P. aeruginosa, 3 A. baumannii) were selected because of resistance to carbapenems. Screening for MBL production was performed in the latter isolates by the combined disk method which depends on comparing the zones given by disks containing imipenem with and without ethylenediaminetetraacetic acid (EDTA). Of imipenem resistant P. aeruginosa strains, 21 and 1 of A. baumannii were found metallo-beta-lactamase producers. Disk approximation studies were then performed to test for in vitro activities of various antimicrobial combinations. For a total of 21 P. aeruginosa strains, synergy was demonstrated predominantly by ciprofloxacin in combination with ceftazidime and imipenem, by ofloxacin in combination with astreonam. Against MBL producer A. baumannii strain, synergy was detected only with imipenem-ofloxacin combination. None of the combinations were antagonistic. These results suggest that MBL producing P. aeruginosa and A. baumanni strains have been introduced into burn centers, and to prevent the further spread of MBL producers, it is essential for carbapenem resistant isolates to be screened for MBLs.

  15. Chemotaxis and degradation of organophosphate compound by a novel moderately thermo-halo tolerant Pseudomonas sp. strain BUR11: evidence for possible existence of two pathways for degradation

    OpenAIRE

    Pailan, Santanu; Saha, Pradipta

    2015-01-01

    An organophosphate (OP) degrading chemotactic bacterial strain BUR11 isolated from an agricultural field was identified as a member of Pseudomonas genus on the basis of its 16S rRNA gene sequence. The strain could utilize parathion, chlorpyrifos and their major hydrolytic intermediates as sole source of carbon for its growth and exhibited positive chemotactic response towards most of them. Optimum concentration of parathion for its growth was recorded to be 200 ppm and 62% of which was degrad...

  16. Role of MexAB-OprM and MexXY-OprM efflux pumps and class 1 integrons in resistance to antibiotics in burn and Intensive Care Unit isolates of Pseudomonas aeruginosa.

    Science.gov (United States)

    Goli, Hamid Reza; Nahaei, Mohammad Reza; Ahangarzadeh Rezaee, Mohammad; Hasani, Alka; Samadi Kafil, Hossein; Aghazadeh, Mohammad; Nikbakht, Mojtaba; Khalili, Younes

    2017-10-06

    The overexpression of efflux pumps and existence of class 1 integrons are the most important mechanisms that contribute to antimicrobial resistance in Pseudomonas aeruginosa especially in burn and Intensive Care Units (ICUs). The present study evaluated the role of MexAB-OprM and MexXY-OprM efflux pumps and class 1 integrons in resistance to antibiotics in burn and ICU isolates of P. aeruginosa. Fifteen burn and forty-two ICU isolates were obtained from four hospitals in Northwest Iran. The isolates were identified and evaluated by the disk diffusion and agar dilution methods for determining antibiotic resistances. The presence of class 1 integrons and associated resistance gene cassettes were detected by PCR and sequencing of the products. The expression levels of efflux pumps were evaluated by phenotypic and genotypic (Quantitative Real-time PCR) methods. The isolates were genotyped by Random Amplified Polymorphic DNA Typing (RAPD-PCR). All burn isolates were integron positive and Multi-drug resistant (MDR), while 78.5% and 69% of ICU isolates were found as MDR and integron positive, respectively. The aadB gene was the most prevalent gene cassette (63.6%) followed by aacA4 (47.7%). Thirty-nine (68.4%) and 43 (75.4%) isolates exhibited an overexpression of MexAB-OprM and MexXY-OprM. Among burn isolates, 80% and 86.6% of them were mexB and mexY overexpressed, while 64.2% and 71.4% of ICU isolates exhibited mexB and mexY overexpression, correspondingly. The isolates were genotyped as 24 different RAPD profiles and were grouped into 15 clusters. The data suggested that class 1 integron had a more significant role than efflux pumps in resistance to beta-lactams and aminoglycosides in burn and ICUs except for gentamicin in burn isolates. Based on our data, it is possible that efflux pumps were not the main cause of high-level resistance to antibiotics. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Use of artificial sputum medium to test antibiotic efficacy against Pseudomonas aeruginosa in conditions more relevant to the cystic fibrosis lung.

    Science.gov (United States)

    Kirchner, Sebastian; Fothergill, Joanne L; Wright, Elli A; James, Chloe E; Mowat, Eilidh; Winstanley, Craig

    2012-06-05

    There is growing concern about the relevance of in vitro antimicrobial susceptibility tests when applied to isolates of P. aeruginosa from cystic fibrosis (CF) patients. Existing methods rely on single or a few isolates grown aerobically and planktonically. Predetermined cut-offs are used to define whether the bacteria are sensitive or resistant to any given antibiotic. However, during chronic lung infections in CF, P. aeruginosa populations exist in biofilms and there is evidence that the environment is largely microaerophilic. The stark difference in conditions between bacteria in the lung and those during diagnostic testing has called into question the reliability and even relevance of these tests. Artificial sputum medium (ASM) is a culture medium containing the components of CF patient sputum, including amino acids, mucin and free DNA. P. aeruginosa growth in ASM mimics growth during CF infections, with the formation of self-aggregating biofilm structures and population divergence. The aim of this study was to develop a microtitre-plate assay to study antimicrobial susceptibility of P. aeruginosa based on growth in ASM, which is applicable to both microaerophilic and aerobic conditions. An ASM assay was developed in a microtitre plate format. P. aeruginosa biofilms were allowed to develop for 3 days prior to incubation with antimicrobial agents at different concentrations for 24 hours. After biofilm disruption, cell viability was measured by staining with resazurin. This assay was used to ascertain the sessile cell minimum inhibitory concentration (SMIC) of tobramycin for 15 different P. aeruginosa isolates under aerobic and microaerophilic conditions and SMIC values were compared to those obtained with standard broth growth. Whilst there was some evidence for increased MIC values for isolates grown in ASM when compared to their planktonic counterparts, the biggest differences were found with bacteria tested in microaerophilic conditions, which showed a much

  18. 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

  19. Meropenem in cystic fibrosis patients infected with resistant Pseudomonas aeruginosa or Burkholderia cepacia and with hypersensitivity to beta-lactam antibiotics

    DEFF Research Database (Denmark)

    Ciofu, Oana; Jensen, Tim; Pressler, Tacjana

    1996-01-01

    in pulmonary function (as a percentage of the predictive values) was 5.6% for FEV1 (forced expiratory volume in the first second) and 8.6% for FVC (forced vital capacity). C-reactive protein and erythrocyte sedimentation rate (ESR) and leukocyte count decreased significantly. In courses administered...... for chronic infection with B. cepacia the post treatment FEV1 and FVC values were higher than the pre-treatment values, and all the inflammatory parameters decreased. The geometric means of minimal inhibitory concentration (MICs) (microg/mL) for P. aeruginosa (B. cepacia) were: tobramycin 6 (59......), ciprofloxacin 1.2 (9.7), piperacillin 49 (16.3), ceftazidime 26 (23), aztreonam 26 (35), imipenem 6.4 (not determined) and meropenem 5.1 (4.8). No statistically significant increase in the MICs of meropenem for either pathogen occurred during therapy. Of the 124 courses, 115 were tolerated without any clinical...

  20. 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 ...

  1. 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...

  2. Biosynthesis and regulation of cyclic lipopeptides in Pseudomonas fluorescens

    NARCIS (Netherlands)

    Bruijn, de I.

    2009-01-01

    Cyclic lipopeptides (CLPs) are surfactant and antibiotic metabolites produced by a variety of bacterial
    genera. For the genus Pseudomonas, many structurally different CLPs have been identified. CLPs play an
    important role in surface motility of Pseudomonas strains, but also in virulence

  3. Cemaran Staphylococcus aureus dan Pseudomonas aerogenosa Pada Stetoskop dirumah Sakit

    Directory of Open Access Journals (Sweden)

    leka lutpiatina

    2017-10-01

    The result of the research was found contamination of Staphylococcus aureus and Pseudomonas aerogenosa on steteskop. The site home condition of the research data was 66.7% cleaned daily, the storage method was placed on the table 70% and the duration of using the set home more than 1 year as much as 70%. The conclusion of stethoscope at Banjarbaru Hospital was contaminated with Staphylococcus aureus by 70% and Pseudomonas aerogenosa by 17%. The suggestion of research can be continued by knowing the existence of Staphylococcus aureus resistant antibiotic and Pseudomonas aerogenous antibiotic resistant at steteskop at Hospital.

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    Morten Alhede

    Full Text Available For a chronic infection to be established, bacteria must be able to cope with hostile conditions such as low iron levels, oxidative stress, and clearance by the host defense, as well as antibiotic treatment. It is generally accepted that biofilm formation facilitates tolerance to these adverse conditions. However, microscopic investigations of samples isolated from sites of chronic infections seem to suggest that some bacteria do not need to be attached to surfaces in order to establish chronic infections. In this study we employed scanning electron microscopy, confocal laser scanning microscopy, RT-PCR as well as traditional culturing techniques to study the properties of Pseudomonas aeruginosa aggregates. We found that non-attached aggregates from stationary-phase cultures have comparable growth rates to surface attached biofilms. The growth rate estimations indicated that, independently of age, both aggregates and flow-cell biofilm had the same slow growth rate as a stationary phase shaking cultures. Internal structures of the aggregates matrix components and their capacity to survive otherwise lethal treatments with antibiotics (referred to as tolerance and resistance to phagocytes were also found to be strikingly similar to flow-cell biofilms. Our data indicate that the tolerance of both biofilms and non-attached aggregates towards antibiotics is reversible by physical disruption. We provide evidence that the antibiotic tolerance is likely to be dependent on both the physiological states of the aggregates and particular matrix components. Bacterial surface-attachment and subsequent biofilm formation are considered hallmarks of the capacity of microbes to cause persistent infections. We have observed non-attached aggregates in the lungs of cystic fibrosis patients; otitis media; soft tissue fillers and non-healing wounds, and we propose that aggregated cells exhibit enhanced survival in the hostile host environment, compared with non

  6. 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 ...

  7. Incidence and antibiotic susceptibility pattern of Staphylococcus ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-06-03

    Jun 3, 2008 ... antibiotic sensitivity test results of suspected cases of urinary tract infection (UTI) of the University of ... (4.4%), Pseudomonas aeruginosa (2.0%) and Candida albican (1.0%). ... and oxfloxacin could be the drug of choice in the treatment of S. aureus. ... appropriate empirical antibiotics that could be of use.

  8. 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...

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

    Science.gov (United States)

    Jensen, Peter Ø; Briales, Alejandra; Brochmann, Rikke P; Wang, Hengzhuang; Kragh, Kasper N; Kolpen, Mette; Hempel, Casper; Bjarnsholt, Thomas; Høiby, Niels; Ciofu, Oana

    2014-04-01

    Antibiotic-tolerant, biofilm-forming Pseudomonas aeruginosa has long been recognized as a major cause of chronic lung infections of cystic fibrosis patients. The mechanisms involved in the activity of antibiotics on biofilm are not completely clear. We have investigated whether the proposed induction of cytotoxic hydroxyl radicals (OH˙) during antibiotic treatment of planktonically grown cells may contribute to action of the commonly used antibiotic ciprofloxacin on P. aeruginosa biofilms. For this purpose, WT PAO1, a catalase deficient ΔkatA and a ciprofloxacin resistant mutant of PAO1 (gyrA), were grown as biofilms in microtiter plates and treated with ciprofloxacin. Formation of OH˙ and total amount of reactive oxygen species (ROS) was measured and viability was estimated. Formation of OH˙ and total ROS in PAO1 biofilms treated with ciprofloxacin was shown but higher levels were measured in ΔkatA biofilms, and no ROS production was seen in the gyrA biofilms. Treatment with ciprofloxacin decreased the viability of PAO1 and ΔkatA biofilms but not of gyrA biofilms. Addition of thiourea, a OH˙ scavenger, decreased the OH˙ levels and killing of PAO1 biofilm. Our study shows that OH˙ is produced by P. aeruginosa biofilms treated with ciprofloxacin, which may contribute to the killing of biofilm subpopulations. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  10. Antibiotics and Antibiotic Resistance

    Science.gov (United States)

    ... all that ails you. Antibiotics, also known as antimicrobial drugs, are drugs that fight infections caused by bacteria. ... Information for Consumers and Health Professionals Information by drug class Antimicrobial Resistance Animal and Veterinary Related Resources Further information ...

  11. pltM is important in the phloroglucinol-mediated crosstalk between biosynthetic gene clusters for the antibiotics 2,4-diacetylphloroglucinol and pyoluteorin in Pseudomonas protegens Pf-5

    Science.gov (United States)

    Pseudomonas protegens strain Pf-5 is a well-characterized rhizosphere bacterium known for its production of a diverse spectrum of antimicrobial secondary metabolites. The production of two of these metabolites, 2,4-diacetylphloroglucinol (2,4-DAPG) and pyoluteorin, is coordinately regulated. Each of...

  12. Sequential interactions of silver-silica nanocomposite (Ag-SiO2 NC) with cell wall, metabolism and genetic stability of Pseudomonas aeruginosa, a multiple antibiotic-resistant bacterium

    Digital Repository Service at National Institute of Oceanography (India)

    Anas, A.; Jiya, J.; Rameez, M.J.; Anand, P.B.; Anantharaman, M.R.; Nair, S.

    The study was carried out to understand the effect of silver–silica nanocomposite (Ag-SiO sub(2)NC) on the cell wall integrity, metabolism and genetic stability of Pseudomonas aeruginosa, a multiple drug-resistant bacterium. Bacterial sensitivity...

  13. Sequential interactions of silver-silica nanocomposite (Ag-SiO2NC) with cell wall, metabolism and genetic stability of Pseudomonas aeruginosa, a multiple antibiotic-resistant bacterium

    Digital Repository Service at National Institute of Oceanography (India)

    Anas, A.; Jiya, J.; Rameez, M.J.; Anand, P.B.; Anantharaman, M.R.; Nair, S.

    The study was carried out to understand the effect of silver-silica nanocomposite (Ag-SiO sub(2)NC) on the cell wall integrity, metabolism and genetic stability of Pseudomonas aeruginosa, a multiple drug-resistant bacterium Bacterial sensitivity...

  14. Bacteriophage-antibiotic synergism to control planktonic and biofilm ...

    African Journals Online (AJOL)

    Bacteriophage-antibiotic synergism to control planktonic and biofilm producing clinical isolates of Pseudomonas aeruginosa. Amina Amal Mahmoud Nouraldin, Manal Mohammad Baddour, Reem Abdel Hameed Harfoush, Sara AbdelAziz Mohamed Essa ...

  15. Peritoneal dialysis-related peritonitis caused by Pseudomonas species: Insight from a post-millennial case series.

    Science.gov (United States)

    Lu, Wanhong; Kwan, Bonnie Ching-Ha; Chow, Kai Ming; Pang, Wing-Fai; Leung, Chi Bon; Li, Philip Kam-To; Szeto, Cheuk Chun

    2018-01-01

    Pseudomonas peritonitis is a serious complication of peritoneal dialysis (PD). However, the clinical course of Pseudomonas peritonitis following the adoption of international guidelines remains unclear. We reviewed the clinical course and treatment response of 153 consecutive episodes of PD peritonitis caused by Pseudomonas species from 2001 to 2015. Pseudomonas peritonitis accounted for 8.3% of all peritonitis episodes. The bacteria isolated were resistant to ceftazidime in 32 cases (20.9%), and to gentamycin in 18 cases (11.8%). In 20 episodes (13.1%), there was a concomitant exit site infection (ESI); in another 24 episodes (15.7%), there was a history of Pseudomonas ESI in the past. The overall primary response rate was 53.6%, and complete cure rate 42.4%. There was no significant difference in the complete cure rate between patients who treated with regimens of 3 and 2 antibiotics. Amongst 76 episodes (46.4%) that failed to respond to antibiotics by day 4, 37 had immediate catheter removal; the other 24 received salvage antibiotics, but only 6 achieved complete cure. Antibiotic resistance is common amongst Pseudomonas species causing peritonitis. Adoption of the treatment guideline leads to a reasonable complete cure rate of Pseudomonas peritonitis. Treatment with three antibiotics is not superior than the conventional two antibiotics regimen. When there is no clinical response after 4 days of antibiotic treatment, early catheter removal should be preferred over an attempt of salvage antibiotic therapy.

  16. Interactions between polymorphonuclear leukocytes and Pseudomonas aeruginosa biofilms on silicone implants in vivo

    DEFF Research Database (Denmark)

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

    2012-01-01

    (PMNs). In contrast, the number of cells of a P. aeruginosa rhlA mutant that cannot produce rhamnolipids was significantly reduced on the implants by day 1, and the bacteria were actively phagocytosed by infiltrating PMNs. In addition, we identified extracellular wire-like structures around the bacteria......Chronic infections with Pseudomonas aeruginosa persist because the bacterium forms biofilms that are tolerant to antibiotic treatment and the host immune response. Scanning electron microscopy and confocal laser scanning microscopy were used to visualize biofilm development in vivo following...... intraperitoneal inoculation of mice with bacteria growing on hollow silicone tubes, as well as to examine the interaction between these bacteria and the host innate immune response. Wild-type P. aeruginosa developed biofilms within 1 day that trapped and caused visible cavities in polymorphonuclear leukocytes...

  17. The implication of Pseudomonas aeruginosa biofilms in infections

    DEFF Research Database (Denmark)

    Rybtke, Morten T; Jensen, Peter Østrup; Høiby, Niels

    2011-01-01

    Biofilm formation by bacteria is recognized as a major problem in chronic infections due to their recalcitrance against the immune defense and available antibiotic treatment schemes. The opportunistic pathogen Pseudomonas aeruginosa has drawn special attention in this regard due to its severity o...... treatment strategies where the underlying targets are less prone for resistance development as bacteria, in retrospect, have a unique ability to evade the actions of classic antibiotics.......Biofilm formation by bacteria is recognized as a major problem in chronic infections due to their recalcitrance against the immune defense and available antibiotic treatment schemes. The opportunistic pathogen Pseudomonas aeruginosa has drawn special attention in this regard due to its severity......-up of the extracellular matrix encasing the biofilm-associated bacteria as well as the elaborate signaling mechanisms employed by the bacterium enables it to withstand the continuous stresses imposed by the immune defense and administered antibiotics resulting in a state of chronic inflammation that damages the host...

  18. Selection of antibiotic resistance at very low antibiotic concentrations.

    Science.gov (United States)

    Sandegren, Linus

    2014-05-01

    Human use of antibiotics has driven the selective enrichment of pathogenic bacteria resistant to clinically used drugs. Traditionally, the selection of resistance has been considered to occur mainly at high, therapeutic levels of antibiotics, but we are now beginning to understand better the importance of selection of resistance at low levels of antibiotics. The concentration of an antibiotic varies in different body compartments during treatment, and low concentrations of antibiotics are found in sewage water, soils, and many water environments due to natural production and contamination from human activities. Selection of resistance at non-lethal antibiotic concentrations (below the wild-type minimum inhibitory concentration) occurs due to differences in growth rate at the particular antibiotic concentration between cells with different tolerance levels to the antibiotic. The minimum selective concentration for a particular antibiotic is reached when its reducing effect on growth of the susceptible strain balances the reducing effect (fitness cost) of the resistance determinant in the resistant strain. Recent studies have shown that resistant bacteria can be selected at concentrations several hundred-fold below the lethal concentrations for susceptible cells. Resistant mutants selected at low antibiotic concentrations are generally more fit than those selected at high concentrations but can still be highly resistant. The characteristics of selection at low antibiotic concentrations, the potential clinical problems of this mode of selection, and potential solutions will be discussed.

  19. Management and treatment of contact lens-related Pseudomonas keratitis

    Directory of Open Access Journals (Sweden)

    Willcox MD

    2012-06-01

    Full Text Available Mark DP WillcoxSchool of Optometry and Vision Science, University of New South Wales, Sydney, AustraliaAbstract: Pubmed and Medline were searched for articles referring to Pseudomonas keratitis between the years 2007 and 2012 to obtain an overview of the current state of this disease. Keyword searches used the terms "Pseudomonas" + "Keratitis" limit to "2007–2012", and ["Ulcerative" or "Microbial"] + "Keratitis" + "Contact lenses" limit to "2007–2012". These articles were then reviewed for information on the percentage of microbial keratitis cases associated with contact lens wear, the frequency of Pseudomonas sp. as a causative agent of microbial keratitis around the world, the most common therapies to treat Pseudomonas keratitis, and the sensitivity of isolates of Pseudomonas to commonly prescribed antibiotics. The percentage of microbial keratitis associated with contact lens wear ranged from 0% in a study from Nepal to 54.5% from Japan. These differences may be due in part to different frequencies of contact lens wear. The frequency of Pseudomonas sp. as a causative agent of keratitis ranged from 1% in Japan to over 50% in studies from India, Malaysia, and Thailand. The most commonly reported agents used to treat Pseudomonas keratitis were either aminoglycoside (usually gentamicin fortified with a cephalosporin, or monotherapy with a fluoroquinolone (usually ciprofloxacin. In most geographical areas, most strains of Pseudomonas sp. (≥95% were sensitive to ciprofloxacin, but reports from India, Nigeria, and Thailand reported sensitivity to this antibiotic and similar fluoroquinolones of between 76% and 90%.Keywords: Pseudomonas, keratitis, contact lens

  20. LONG-TERM STARVATION-INDUCED LOSS OF APPARENT ANTIBIOTIC RESISTANCE IN CELLS CONTAINING THE PLASMID PSA

    Science.gov (United States)

    Escherichia coli, Pseudomonas fluorescens, and a Pseudomonas sp. strain 133B containing the pSa plasmid were starved in well water for up to 523 days. There were two patterns of apparent antibiotic resistance loss observed. In Pseudomonas sp. strain 133B, there was no apparent lo...

  1. The Effect of Antioxidants on Antibiotic Sensitivity of Bacteria

    OpenAIRE

    Azade ATTAR; Akif İ. QURBANOV

    2007-01-01

    Objective: The effect of different concentrations of antioxidants (ascorbic acid, emoxipin, tocopherol acetate and ionol) on antibiotic sensitivity of bacteria was studied. Method: Bacteria belong to different respiration types: Pseudomonas aeruginosa as aerobe and Escherichia coli as facultative anaerobe were used. Antibiotic sensitivity of microorganisms was determined as minimum inhibitory concentration (MIC) by dilution test. Results: Different concentrations of antioxidants increased the...

  2. In Vitro Antibiotic Susceptibility Studies Of Bacteria Associated With ...

    African Journals Online (AJOL)

    In vitro tests of the susceptibility of isolates of bacterial keratitis pathogens to antibiotics were carried out in this study. Staphylococcus aureus was the most frequently isolated organisms followed by Pseudomonas aeruginosa and Streptococcus pneumoniae. Antibiotic sensitivity testing showed a high susceptibility to ...

  3. [Risk factors for Pseudomonas aeruginosa infections, resistant to carbapenem].

    Science.gov (United States)

    Ghibu, Laura; Miftode, Egidia; Teodor, Andra; Bejan, Codrina; Dorobăţ, Carmen Mihaela

    2010-01-01

    Since their introduction in clinical practice,carbapenems have been among the most powerful antibiotics for treating serious infections cased by Gram-negative nosocomial pathogens, including Pseudomonas aeruginosa. The emergence of betalactamases with carbapenem-hydrolyzing activity is of major clinical concern. Pseudomonas aeruginosa is a leading cause of nosocomial infection. Risk factors for colonization with carbapenems-resistant Pseudomonas in hospital are: history of P. aeruginosa infection or colonization within the previous year, (length of hospital stay, being bedridden or in the ICU, mechanical ventilation, malignant disease, and history of chronic obstructive pulmonary disease have all been identified as independent risk factors for MDR P. aeruginosa infection. Long-term-care facilities are also reservoirs of resistant bacteria. Risk factors for colonization of LTCF residents with resistant bacteria included age > 86 years, antibiotic treatment in the previous 3 months, indwelling devices, chronic obstructive pulmonary disease, physical disability, and the particular LTCF unit.

  4. Ranking of persister genes in the same Escherichia coli genetic background demonstrates varying importance of individual persister genes in tolerance to different antibiotics

    Directory of Open Access Journals (Sweden)

    Nan eWu

    2015-09-01

    Full Text Available Despite the identification of many genes and pathways involved in the persistence phenomenon of bacteria, the relative importance of these genes in a single organism remains unclear. Here, using Escherichia coli as a model, we generated mutants of 21 known candidate persister genes and compared the relative importance of these mutants in persistence to various antibiotics (ampicillin, gentamicin, norfloxacin, and trimethoprim at different times. We found that oxyR, dnaK, sucB, relA, rpoS, clpB, mqsR, and recA were prominent persister genes involved in persistence to multiple antibiotics. These genes map to the following pathways: antioxidative defense pathway (oxyR, global regulators (dnaK, clpB, and rpoS, energy production (sucB, stringent response (relA, toxin–antitoxin (TA module (mqsR, and SOS response (recA. Among the TA modules, the ranking order was mqsR, lon, relE, tisAB, hipA, and dinJ. Intriguingly, rpoS deletion caused a defect in persistence to gentamicin but increased persistence to ampicillin and norfloxacin. Mutants demonstrated dramatic differences in persistence to different antibiotics at different time points: some mutants (oxyR, dnaK, phoU, lon, recA, mqsR, and tisAB displayed defect in persistence from early time points, while other mutants (relE, smpB, glpD, umuD, and tnaA showed defect only at later time points. These results indicate that varying hierarchy and importance of persister genes exist and that persister genes can be divided into those involved in shallow persistence and those involved in deep persistence. Our findings suggest that the persistence phenomenon is a dynamic process with different persister genes playing roles of variable significance at different times. These findings have implications for improved understanding of persistence phenomenon and developing new drugs targeting persisters for more effective cure of persistent infections.

  5. Peptide Antibiotics for ESKAPE Pathogens

    DEFF Research Database (Denmark)

    Thomsen, Thomas Thyge

    is considered poor compared to medicines for lifestyle diseases. According to the WHO we could be moving towards a post-antibiotic era in which previously treatable infections become fatal. Of special importance are multidrug resistant bacteria from the ESKAPE group (Enterococcus faecium, Staphylococcus aureus......Multi-drug resistance to antibiotics represents a global health challenge that results in increased morbidity and mortality rates. The annual death-toll is >700.000 people world-wide, rising to ~10 million by 2050. New antibiotics are lacking, and few are under development as return on investment......, Klebsiella pneumoniae, Acinetobacter, Pseudomonas aeruginosa and Enterobacter). As a consequence of widespread multi-drug resistance, researchers have sought for alternative sources of antimicrobials. Antimicrobial peptides are produced by almost all living organisms as part of their defense or innate immune...

  6. The Small Colony Variant of Listeria monocytogenes Is More Tolerant to Antibiotics and Has Altered Survival in RAW 264.7 Murine Macrophages

    DEFF Research Database (Denmark)

    Curtis, Thomas; Gram, Lone; Knudsen, Gitte Maegaard

    2016-01-01

    Small Colony Variant (SCV) cells of bacteria are a slow-growing phenotype that result from specific defects in the electron transport chain. They form pinpoint colonies on agar plates and have a variety of phenotypic characteristics, such as altered carbon metabolism, decreased toxin and lytic...... monocytogenes (strain SCV E18), similar to the high persister mutant phenotype, survived significantly better than the wild type when exposed over a 48-h period to concentrations above Minimal Inhibitory Concentration for most tested antibiotics. SCV E18 survived more poorly than the wildtype in unactivated RAW......264.7 macrophage cells, presumably because of its reduced listeriolysin O expression, however, it survived better in reactive oxygen species producing, phorbol 12-myristate 13-acetate-activated macrophages. Although SCV E18 was sensitive to oxygen as it entered the stationary phase...

  7. PSEUDOMONAS AERUGINOSA IN CHRONIC SUPPURATIVE OTITIS MEDIA- A DRUGSENSITIVITY STUDY

    Directory of Open Access Journals (Sweden)

    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.

  8. Efflux mediated adaptive and cross resistance to ciprofloxacin and benzalkonium chloride in Pseudomonas aeruginosa of dairy origin.

    Science.gov (United States)

    Pagedar, Ankita; Singh, Jitender; Batish, Virender K

    2011-06-01

    The present study was undertaken to investigate the role of efflux pump activity (EPA) in conferring adaptive and cross resistances against ciprofloxacin (CF) and benzalkonium chloride (BC) in dairy isolates of Pseudomonas aeruginosa. Biofilm formation potential was correlated with development of adaptive resistance in originally resistant strains. Irrespective of parent strains's susceptibility, isolates developed substantial adaptive resistance against CF and BC. Significant difference was observed in ability of non resistant isolates to develop adaptive resistance against CF and BC (P Reduction in adaptive resistances due to EPI was more evident in originally non resistant strains, which reaffirms EPA as probable mechanism of adaptive resistance. The present study perhaps first of its kind, suggests an active role of EPA in conferring adaptive and cross resistances in food related P. aeruginosa isolates and supports reverse hypothesis that antibiotic-resistant organisms eventually become tolerant to other antibacterial agents as well. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Large-area burns with pandrug-resistant Pseudomonas aeruginosa infection and respiratory failure.

    Science.gov (United States)

    Ning, Fang-Gang; Zhao, Xiao-Zhuo; Bian, Jing; Zhang, Guo-An

    2011-02-01

    Infection due to pandrug-resistant Pseudomonas aeruginosa (PDRPA) has become a challenge in clinical practice. The aim of this research was to summarize the treatment of large-area burns (60% - 80%) with PDRPA infection and respiratory failure in our hospital over the last two years, and to explore a feasible treatment protocol for such patients. We retrospectively analyzed the treatment of five patients with large-area burns accompanied by PDRPA infection and respiratory failure transferred to our hospital from burn units in hospitals in other Chinese cities from January 2008 to February 2010. Before PDRPA infection occurred, all five patients had open wounds with large areas of granulation because of the failure of surgery and dissolving of scar tissue; they had also undergone long-term administration of carbapenems. This therapy included ventilatory support, rigorous repair of wounds, and combined antibiotic therapy targeted at drug-resistance mechanisms, including carbapenems, ciprofloxacin, macrolide antibiotics and β-lactamase inhibitors. Four patients recovered from burns and one died after therapy. First, compromised immunity caused by delayed healing of burn wounds in patients with large-area burns and long-term administration of carbapenems may be the important factors in the initiation and progression of PDRPA infection. Second, if targeted at drug-resistance mechanisms, combined antibiotic therapy using carbapenems, ciprofloxacin, macrolide antibiotics and β-lactamase inhibitors could effectively control PDRPA infection. Third, although patients with large-area burns suffered respiratory failure and had high risks from anesthesia and surgery, only aggressive skin grafting with ventilatory support could control the infection and save lives. Patients may not be able to tolerate a long surgical procedure, so the duration of surgery should be minimized, and the frequency of surgery increased.

  10. Antivirulence activity of azithromycin in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    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.

  11. Diversity of metabolic profiles of cystic fibrosis Pseudomonas aeruginosa during the early stages of lung infection

    DEFF Research Database (Denmark)

    Jørgensen, Karin Meinike; Wassermann, Tina; Johansen, Helle Krogh

    2015-01-01

    Pseudomonas aeruginosa is the dominant pathogen infecting the airways of cystic fibrosis (CF) patients. During the intermittent colonization phase, P. aeruginosa resembles environmental strains but later evolves to the chronic adapted phenotype characterized by resistance to antibiotics and mutat......Pseudomonas aeruginosa is the dominant pathogen infecting the airways of cystic fibrosis (CF) patients. During the intermittent colonization phase, P. aeruginosa resembles environmental strains but later evolves to the chronic adapted phenotype characterized by resistance to antibiotics...

  12. 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...

  13. 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.

  14. Pseudomonas Lipopeptide Biosurfactants

    DEFF Research Database (Denmark)

    Bonnichsen, Lise

    Pseudomonas lipopetide biosurfactants are amphiphilic molecules with a broad range of natural functions. Due to their surface active properties, it has been suggested that Pseudomonas lipopetides potentially play a role in biodegradation of hydrophobic compounds and have essential functions...... lipopetide biosurfactants in pollutant biodegradation and natural roles in biofilm formation. The work presented is a combination of environmental microbiology and exploiting genetic manipulation of pure cultures to achieve insightinto the effects and mechanisms of lipopeptides on microbial processes...

  15. The relBE2Spn toxin-antitoxin system of Streptococcus pneumoniae: role in antibiotic tolerance and functional conservation in clinical isolates.

    Directory of Open Access Journals (Sweden)

    Concha Nieto

    2010-06-01

    Full Text Available Type II (proteic chromosomal toxin-antitoxin systems (TAS are widespread in Bacteria and Archaea but their precise function is known only for a limited number of them. Out of the many TAS described, the relBE family is one of the most abundant, being present in the three first sequenced strains of Streptococcus pneumoniae (D39, TIGR4 and R6. To address the function of the pneumococcal relBE2Spn TAS in the bacterial physiology, we have compared the response of the R6-relBE2Spn wild type strain with that of an isogenic derivative, Delta relB2Spn under different stress conditions such as carbon and amino acid starvation and antibiotic exposure. Differences on viability between the wild type and mutant strains were found only when treatment directly impaired protein synthesis. As a criterion for the permanence of this locus in a variety of clinical strains, we checked whether the relBE2Spn locus was conserved in around 100 pneumococcal strains, including clinical isolates and strains with known genomes. All strains, although having various types of polymorphisms at the vicinity of the TA region, contained a functional relBE2Spn locus and the type of its structure correlated with the multilocus sequence type. Functionality of this TAS was maintained even in cases where severe rearrangements around the relBE2Spn region were found. We conclude that even though the relBE2Spn TAS is not essential for pneumococcus, it may provide additional advantages to the bacteria for colonization and/or infection.

  16. Forgotten antibiotics

    DEFF Research Database (Denmark)

    Pulcini, Céline; Bush, Karen; Craig, William A

    2012-01-01

    In view of the alarming spread of antimicrobial resistance in the absence of new antibiotics, this study aimed at assessing the availability of potentially useful older antibiotics. A survey was performed in 38 countries among experts including hospital pharmacists, microbiologists, and infectious...

  17. Vesiculation from Pseudomonas aeruginosa under SOS.

    Science.gov (United States)

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

    2012-01-01

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

  18. 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

  19. Genetic architecture of intrinsic antibiotic susceptibility.

    Directory of Open Access Journals (Sweden)

    Hany S Girgis

    2009-05-01

    Full Text Available Antibiotic exposure rapidly selects for more resistant bacterial strains, and both a drug's chemical structure and a bacterium's cellular network affect the types of mutations acquired.To better characterize the genetic determinants of antibiotic susceptibility, we exposed a transposon-mutagenized library of Escherichia coli to each of 17 antibiotics that encompass a wide range of drug classes and mechanisms of action. Propagating the library for multiple generations with drug concentrations that moderately inhibited the growth of the isogenic parental strain caused the abundance of strains with even minor fitness advantages or disadvantages to change measurably and reproducibly. Using a microarray-based genetic footprinting strategy, we then determined the quantitative contribution of each gene to E. coli's intrinsic antibiotic susceptibility. We found both loci whose removal increased general antibiotic tolerance as well as pathways whose down-regulation increased tolerance to specific drugs and drug classes. The beneficial mutations identified span multiple pathways, and we identified pairs of mutations that individually provide only minor decreases in antibiotic susceptibility but that combine to provide higher tolerance.Our results illustrate that a wide-range of mutations can modulate the activity of many cellular resistance processes and demonstrate that E. coli has a large mutational target size for increasing antibiotic tolerance. Furthermore, the work suggests that clinical levels of antibiotic resistance might develop through the sequential accumulation of chromosomal mutations of small individual effect.

  20. Antibiotic resistance

    Directory of Open Access Journals (Sweden)

    Marianne Frieri

    2017-07-01

    Full Text Available Summary: Antimicrobial resistance in bacterial pathogens is a challenge that is associated with high morbidity and mortality. Multidrug resistance patterns in Gram-positive and -negative bacteria are difficult to treat and may even be untreatable with conventional antibiotics. There is currently a shortage of effective therapies, lack of successful prevention measures, and only a few new antibiotics, which require development of novel treatment options and alternative antimicrobial therapies. Biofilms are involved in multidrug resistance and can present challenges for infection control. Virulence, Staphylococcus aureus, Clostridium difficile infection, vancomycin-resistant enterococci, and control in the Emergency Department are also discussed. Keywords: Antibiotic resistance, Biofilms, Infections, Public health, Emergency Department

  1. 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....

  2. Efficacy and Safety of Inhaled Aztreonam Lysine for Airway Pseudomonas in Cystic Fibrosis

    Science.gov (United States)

    Retsch-Bogart, George Z.; Quittner, Alexandra L.; Gibson, Ronald L.; Oermann, Christopher M.; McCoy, Karen S.; Montgomery, A. Bruce; Cooper, Peter J.

    2009-01-01

    Background: We assessed the short-term efficacy and safety of aztreonam lysine for inhalation (AZLI [an aerosolized monobactam antibiotic]) in patients with cystic fibrosis (CF) and Pseudomonas aeruginosa (PA) airway infection. Methods: In this randomized, double-blind, placebo-controlled, international study (AIR-CF1 trial; June 2005 to April 2007), patients (n = 164; ≥ 6 years of age) with FEV1 ≥ 25% and ≤ 75% predicted values, and no recent use of antipseudomonal antibiotics or azithromycin were treated with 75 mg of AZLI (three times daily for 28 days) or placebo (1:1 randomization), then were monitored for 14 days after study drug completion. The primary efficacy end point was change in patient-reported respiratory symptoms (CF-Questionnaire-Revised [CFQ-R] Respiratory Scale). Secondary end points included changes in pulmonary function (FEV1), sputum PA density, and nonrespiratory CFQ-R scales. Adverse events and minimum inhibitory concentrations of aztreonam for PA were monitored. Results: After 28 days of treatment, AZLI improved the mean CFQ-R respiratory score (9.7 points; p < 0.001), FEV1 (10.3% predicted; p < 0.001), and sputum PA density (− 1.453 log10 cfu/g; p < 0.001), compared with placebo. Significant improvements in Eating, Emotional Functioning, Health Perceptions, Physical Functioning, Role Limitation/School Performance, and Vitality CFQ-R scales were observed. Adverse events were consistent with symptoms of CF lung disease and were comparable for AZLI and placebo except the incidence of “productive cough” was reduced by half in AZLI-treated patients. PA aztreonam susceptibility at baseline and end of therapy were similar. Conclusions: In patients with CF, PA airway infection, moderate-to-severe lung disease, and no recent use of antipseudomonal antibiotics or azithromycin, 28-day treatment with AZLI significantly improved respiratory symptoms and pulmonary function, and was well tolerated. Trial registration: Clinicaltrials

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  4. An Antipersister Strategy for Treatment of Chronic Pseudomonas aeruginosa Infections.

    Science.gov (United States)

    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.

  5. Antibiotic resistance in hospitals: a ward-specific random effect model in a low antibiotic consumption environment.

    Science.gov (United States)

    Aldrin, Magne; Raastad, Ragnhild; Tvete, Ingunn Fride; Berild, Dag; Frigessi, Arnoldo; Leegaard, Truls; Monnet, Dominique L; Walberg, Mette; Müller, Fredrik

    2013-04-15

    Association between previous antibiotic use and emergence of antibiotic resistance has been reported for several microorganisms. The relationship has been extensively studied, and although the causes of antibiotic resistance are multi-factorial, clear evidence of antibiotic use as a major risk factor exists. Most studies are carried out in countries with high consumption of antibiotics and corresponding high levels of antibiotic resistance, and currently, little is known whether and at what level the associations are detectable in a low antibiotic consumption environment. We conduct an ecological, retrospective study aimed at determining the impact of antibiotic consumption on antibiotic-resistant Pseudomonas aeruginosa in three hospitals in Norway, a country with low levels of antibiotic use. We construct a sophisticated statistical model to capture such low signals. To reduce noise, we conduct our study at hospital ward level. We propose a random effect Poisson or binomial regression model, with a reparametrisation that allows us to reduce the number of parameters. Inference is likelihood based. Through scenario simulation, we study the potential effects of reduced or increased antibiotic use. Results clearly indicate that the effects of consumption on resistance are present under conditions with relatively low use of antibiotic agents. This strengthens the recommendation on prudent use of antibiotics, even when consumption is relatively low. Copyright © 2012 John Wiley & Sons, Ltd.

  6. 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.

  7. Assessment of Risk Factors, Treatment and Hospital Stay in Complicated Urinary Tract Infections in Men Caused by Pseudomonas: A Case-Control Study

    Directory of Open Access Journals (Sweden)

    Hasan Selçuk Özger

    2017-06-01

    Full Text Available Objective: It is known that Pseudomonas has been isolated more frequently in health care-related urinary tract infections (UTIs. It was aimed to determine the risk factors and empiric therapies due to antibiotic resistance in Pseudomonas-related male UTIs, and assess the effect of Pseudomonas isolation on treatment and length of hospital stay. Materials and Methods: The study was conducted between January 2011 and January 2013 with 228 male health care-related complicated UTI patients hospitalized in the Urology and Infectious Diseases Inpatient Clinics at Gazi University Faculty of Medicine. Three hundred UTI attacks in 228 patients were evaluated retrospectively with regard to agents. Results: Pseudomonas was isolated in 37 of 300 complicated UTI attacks in 228 male patients. Nephrolithiasis, recurrent UTI and internal urinary catheterization were determined as the risk factors for Pseudomonas related with health care-related UTI. It was understood that nephrolithiasis increased Pseudomonas isolated UTI risk 3.5 fold and recurrent UTI increased the risk 8.9 fold. The antibiotic resistance of Pseudomonas was higher than other agents. Pseudomonas related UTIs prolonged the duration of hospital stay and antibiotic treatment. Conclusion: In the presence of nephrolithiasis, recurrent UTI and internal urinary catheterization, drugs against Pseudomonas would be appropriate empiric treatment for health care-related complicated UTI. Ciprofloxacin use should be restricted when local antibiotic resistance, which leads empiric treatment, is taken into consideration. Increases in hospital stay and antibiotic treatment duration were thought to be associated with recurrent infection frequency and high antibiotics resistance in Pseudomonas related UTIs.

  8. Cellular responses of A549 alveolar epithelial cells to serially collected Pseudomonas aeruginosa from cystic fibrosis patients at different stages of pulmonary infection

    DEFF Research Database (Denmark)

    Hawdon, Nicole A; Aval, Pouya Sadeghi; Barnes, Rebecca J

    2010-01-01

    Pseudomonas aeruginosa is the major cause of chronic pulmonary disease in cystic fibrosis (CF) patients. During chronic infection, P. aeruginosa lose certain virulence factors, transform into a mucoid phenotype, and develop antibiotic resistance. We hypothesized that these genetic and phenotypic ...

  9. Antibiotic Resistance

    DEFF Research Database (Denmark)

    Munck, Christian

    morbidity and mortality as well as an increase in the cost of treatment. Understanding how bacteria respond to antibiotic exposure gives the foundations for a rational approach to counteract antimicrobial resistance. In the work presented in this thesis, I explore the two fundamental sources...... of antimicrobial resistance: (1) adaptive mutations and (2) horizontal acquisition of resistance genes from antibiotic gene reservoirs. By studying the geno- and phenotypic changes of E. coli in response to single and drug-pair exposures, I uncover the evolutionary trajectories leading to adaptive resistance. I...... to rationally design drug combinations that limit the evolution of antibiotic resistance due to counteracting evolutionary trajectories. My results highlight that an in-depth knowledge about the genetic responses to the individual antimicrobial compounds enables the prediction of responses to drug combinations...

  10. The Versatile Mutational Resistome of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Carla López-Causapé

    2018-04-01

    Full Text Available One of the most striking features of Pseudomonas aeruginosa is its outstanding capacity for developing antimicrobial resistance to nearly all available antipseudomonal agents through the selection of chromosomal mutations, leading to the failure of the treatment of severe hospital-acquired or chronic infections. Recent whole-genome sequencing (WGS data obtained from in vitro assays on the evolution of antibiotic resistance, in vivo monitoring of antimicrobial resistance development, analysis of sequential cystic fibrosis isolates, and characterization of widespread epidemic high-risk clones have provided new insights into the evolutionary dynamics and mechanisms of P. aeruginosa antibiotic resistance, thus motivating this review. Indeed, the analysis of the WGS mutational resistome has proven to be useful for understanding the evolutionary dynamics of classical resistance pathways and to describe new mechanisms for the majority of antipseudomonal classes, including β-lactams, aminoglycosides, fluoroquinolones, or polymixins. Beyond addressing a relevant scientific question, the analysis of the P. aeruginosa mutational resistome is expected to be useful, together with the analysis of the horizontally-acquired resistance determinants, for establishing the antibiotic resistance genotype, which should correlate with the antibiotic resistance phenotype and as such, it should be useful for the design of therapeutic strategies and for monitoring the efficacy of administered antibiotic treatments. However, further experimental research and new bioinformatics tools are still needed to overcome the interpretation limitations imposed by the complex interactions (including those leading to collateral resistance or susceptibility between the 100s of genes involved in the mutational resistome, as well as the frequent difficulties for differentiating relevant mutations from simple natural polymorphisms.

  11. The Versatile Mutational Resistome of Pseudomonas aeruginosa.

    Science.gov (United States)

    López-Causapé, Carla; Cabot, Gabriel; Del Barrio-Tofiño, Ester; Oliver, Antonio

    2018-01-01

    One of the most striking features of Pseudomonas aeruginosa is its outstanding capacity for developing antimicrobial resistance to nearly all available antipseudomonal agents through the selection of chromosomal mutations, leading to the failure of the treatment of severe hospital-acquired or chronic infections. Recent whole-genome sequencing (WGS) data obtained from in vitro assays on the evolution of antibiotic resistance, in vivo monitoring of antimicrobial resistance development, analysis of sequential cystic fibrosis isolates, and characterization of widespread epidemic high-risk clones have provided new insights into the evolutionary dynamics and mechanisms of P. aeruginosa antibiotic resistance, thus motivating this review. Indeed, the analysis of the WGS mutational resistome has proven to be useful for understanding the evolutionary dynamics of classical resistance pathways and to describe new mechanisms for the majority of antipseudomonal classes, including β-lactams, aminoglycosides, fluoroquinolones, or polymixins. Beyond addressing a relevant scientific question, the analysis of the P. aeruginosa mutational resistome is expected to be useful, together with the analysis of the horizontally-acquired resistance determinants, for establishing the antibiotic resistance genotype, which should correlate with the antibiotic resistance phenotype and as such, it should be useful for the design of therapeutic strategies and for monitoring the efficacy of administered antibiotic treatments. However, further experimental research and new bioinformatics tools are still needed to overcome the interpretation limitations imposed by the complex interactions (including those leading to collateral resistance or susceptibility) between the 100s of genes involved in the mutational resistome, as well as the frequent difficulties for differentiating relevant mutations from simple natural polymorphisms.

  12. Raoultella ornithinolytica Diagnosed in a Neurointensive Patient. A Rare Case with Recovery without Antibiotics

    DEFF Research Database (Denmark)

    Jellinge, Marlene Ersgaard

    2017-01-01

    Infection with Raoultella ornithinolytica is rare and normally the infection is present in patients with underlying malignancies or chronic diseases. It is normally treated with antibiotics. In this case report, a neuro-intensive patient without malignancies or other severe chronic diseases...... was colonized with Pseudomonas aeruginosa but infected with Raoultella ornithinolyca. The patient recovered without treatment with antibiotics....

  13. Pseudomonas aeruginosa ventilator-associated pneumonia management

    Directory of Open Access Journals (Sweden)

    Ramírez-Estrada S

    2016-01-01

    Full Text Available Sergio Ramírez-Estrada,1 Bárbara Borgatta,1,2 Jordi Rello3,4 1Critical Care Department, Vall d'Hebron University Hospital, 2CRIPS, Vall d'Hebron Institute of Research (VHIR, 3Department of Medicine, Universitat Autònoma de Barcelona (UAB, Barcelona, 4Centro de Investigación Biomédica en Red Enfermedad Respiratoria – CIBERES, Madrid, Spain Abstract: 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. Keywords: multidrug-resistant, ICU, new-antibiotics, adjunctive-therapies, care-bundles

  14. The Pseudomonas aeruginosa PSL Polysaccharide Is a Social but Noncheatable Trait in Biofilms.

    Science.gov (United States)

    Irie, Yasuhiko; Roberts, Aled E L; Kragh, Kasper N; Gordon, Vernita D; Hutchison, Jaime; Allen, Rosalind J; Melaugh, Gavin; Bjarnsholt, Thomas; West, Stuart A; Diggle, Stephen P

    2017-06-20

    Extracellular polysaccharides are compounds secreted by microorganisms into the surrounding environment, and they are important for surface attachment and maintaining structural integrity within biofilms. The social nature of many extracellular polysaccharides remains unclear, and it has been suggested that they could function as either cooperative public goods or as traits that provide a competitive advantage. Here, we empirically tested the cooperative nature of the PSL polysaccharide, which is crucial for the formation of biofilms in Pseudomonas aeruginosa We show that (i) PSL is not metabolically costly to produce; (ii) PSL provides population-level benefits in biofilms, for both growth and antibiotic tolerance; (iii) the benefits of PSL production are social and are shared with other cells; (iv) the benefits of PSL production appear to be preferentially directed toward cells which produce PSL; (v) cells which do not produce PSL are unable to successfully exploit cells which produce PSL. Taken together, this suggests that PSL is a social but relatively nonexploitable trait and that growth within biofilms selects for PSL-producing strains, even when multiple strains are on a patch (low relatedness at the patch level). IMPORTANCE Many studies have shown that bacterial traits, such as siderophores and quorum sensing, are social in nature. This has led to an impression that secreted traits act as public goods, which are costly to produce but benefit both the producing cell and its surrounding neighbors. Theories and subsequent experiments have shown that such traits are exploitable by asocial cheats, but we show here that this does not always hold true. We demonstrate that the Pseudomonas aeruginosa exopolysaccharide PSL provides social benefits to populations but that it is nonexploitable, because most of the fitness benefits accrue to PSL-producing cells. Our work builds on an increasing body of work showing that secreted traits can have both private and public

  15. Combating Antibiotic Resistance

    Science.gov (United States)

    ... Bacteria Phasing Out Certain Antibiotic Use in Farm Animals FDA: Cutting-Edge Technology Sheds Light on Antibiotic Resistance For More Information Antibiotics and Antibiotic Resistance Antimicrobial Resistance Information for Consumers and Health Professionals CDC: ...

  16. Antimicrobial resistance of Pseudomonas spp. isolated from wastewater and wastewater-impacted marine coastal zone.

    Science.gov (United States)

    Luczkiewicz, Aneta; Kotlarska, Ewa; Artichowicz, Wojciech; Tarasewicz, Katarzyna; Fudala-Ksiazek, Sylwia

    2015-12-01

    In this study, species distribution and antimicrobial susceptibility of cultivated Pseudomonas spp. were studied in influent (INF), effluent (EFF), and marine outfall (MOut) of wastewater treatment plant (WWTP). The susceptibility was tested against 8 antimicrobial classes, active against Pseudomonas spp.: aminoglycosides, carbapenems, broad-spectrum cephalosporins from the 3rd and 4th generation, extended-spectrum penicillins, as well as their combination with the β-lactamase inhibitors, monobactams, fluoroquinolones, and polymyxins. Among identified species, resistance to all antimicrobials but colistin was shown by Pseudomonas putida, the predominant species in all sampling points. In other species, resistance was observed mainly against ceftazidime, ticarcillin, ticarcillin-clavulanate, and aztreonam, although some isolates of Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas pseudoalcaligenes, and Pseudomonas protegens showed multidrug-resistance (MDR) phenotype. Among P. putida, resistance to β-lactams and to fluoroquinolones as well as multidrug resistance become more prevalent after wastewater treatment, but the resistance rate decreased in marine water samples. Obtained data, however, suggests that Pseudomonas spp. are equipped or are able to acquire a wide range of antibiotic resistance mechanisms, and thus should be monitored as possible source of resistance genes.

  17. Incidence and Antibiotic Susceptibility Pattern of Bacterial Isolates ...

    African Journals Online (AJOL)

    In vitro antibiotic susceptibility tests showed that Pseudomonas aeruginosa was susceptible to ceftazidime, ciprofloxacin and gentamicin while the enteric bacteria were generally more resistant to ceftazidime, gentamicin and ciprofloxacin. Conclusion: The findings show that there is a high rate of wound infection in Kano, ...

  18. 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...

  19. Prescribing Antibiotics

    DEFF Research Database (Denmark)

    Pedersen, Inge Kryger; Jepsen, Kim Sune

    2018-01-01

    The medical professions will lose an indispensable tool in clinical practice if even simple infections cannot be cured because antibiotics have lost effectiveness. This article presents results from an exploratory enquiry into “good doctoring” in the case of antibiotic prescribing at a time when...... the knowledge base in the healthcare field is shifting. Drawing on in-depth interviews about diagnosing and prescribing, the article demonstrates how the problem of antimicrobial resistance is understood and engaged with by Danish general practitioners. When general practitioners speak of managing “non......-medical issues,” they refer to routines, clinical expertise, experiences with their patients, and decision-making based more on contextual circumstances than molecular conditions—and on the fact that such conditions can be hard to assess. This article’s contribution to knowledge about how new and global health...

  20. [Virulence and its relationship to antibiotic resistance].

    Science.gov (United States)

    Joly-Guillou, M L

    1998-12-01

    PATHOGENIC ISLANDS: Certain DNA blocks inserted into the chromosome of most Gram negative bacteria originated in pathogens found in plants. VIRULENCE-ANTIBIOTIC INTERACTIONS: During the invasive phase, the bacterial cell covers itself with adhesins which facilitate its adherence to tissues. The bacterial cell produces a fibronectin which protects its defense systems. Antibiotics favor bacterial resistance by increasing the expression of surface adhesins and fibronectin production. PENICILLIN RESISTANT PNEUMOCOCCI: Experimental models have demonstrated that mortality in mice and host resistance to pneumococcal infection are related to the type of capsule and not to antibiotic resistance. QUORUM SENSING: The bacterial inoculum regulates the production of virulence factors in vivo via quorum sensing. This regulation can play an important role in Pseudomonas aeruginosa infections. ACINETOBACTER BAUMANNI VIRULENCE: Long poorly understood, factors favoring A. baumanni virulence appear to result from bacterial production of IROMPs in the extracellular growth medium in response to iron depletion during the exponential growth phase.

  1. The rare codon AGA is involved in regulation of pyoluteorin biosynthesis in Pseudomonas protegens Pf-5

    Science.gov (United States)

    The soil bacterium Pseudomonas protegens Pf-5 can colonize root and seed surfaces of many plants, protecting them from infection by plant pathogenic fungi and oomycetes. This capacity to suppress disease is attributed in part to Pf-5’s production of a large spectrum of antibiotics, which is controll...

  2. Antibiotic resistance in Burkholderia species.

    Science.gov (United States)

    Rhodes, Katherine A; Schweizer, Herbert P

    2016-09-01

    The genus Burkholderia comprises metabolically diverse and adaptable Gram-negative bacteria, which thrive in often adversarial environments. A few members of the genus are prominent opportunistic pathogens. These include Burkholderia mallei and Burkholderia pseudomallei of the B. pseudomallei complex, which cause glanders and melioidosis, respectively. Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia vietnamiensis belong to the Burkholderia cepacia complex and affect mostly cystic fibrosis patients. Infections caused by these bacteria are difficult to treat because of significant antibiotic resistance. The first line of defense against antimicrobials in Burkholderia species is the outer membrane penetration barrier. Most Burkholderia contain a modified lipopolysaccharide that causes intrinsic polymyxin resistance. Contributing to reduced drug penetration are restrictive porin proteins. Efflux pumps of the resistance nodulation cell division family are major players in Burkholderia multidrug resistance. Third and fourth generation β-lactam antibiotics are seminal for treatment of Burkholderia infections, but therapeutic efficacy is compromised by expression of several β-lactamases and ceftazidime target mutations. Altered DNA gyrase and dihydrofolate reductase targets cause fluoroquinolone and trimethoprim resistance, respectively. Although antibiotic resistance hampers therapy of Burkholderia infections, the characterization of resistance mechanisms lags behind other non-enteric Gram-negative pathogens, especially ESKAPE bacteria such as Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. 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.

  4. Multiple Antibiotic Resistance (MAR) indices of Pseudomonas and ...

    African Journals Online (AJOL)

    AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy Makers · about Open Access · Journal Quality.

  5. 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.

  6. Diagnostic significance of measurements of specific IgG antibodies to Pseudomonas aeruginosa by three different serological methods

    DEFF Research Database (Denmark)

    Pressler, T.; Karpati, F.; Granstrom, M.

    2008-01-01

    to characterize patients with different infection status. Elevated levels of specific anti-Pseudomonas antibodies showed to be the risk factor for developing chronic Pa infection. Due to the specificity of the tests, antibiotic treatment based on serology might be considered in selected cases. There is a window...... of opportunity for suppression and eradication of initial P. aeruginosa infection making measurement of specific anti-Pseudomonas antibodies helpful Udgivelsesdato: 2009/1...

  7. Polymorphisms within the prnD and pltC genes from pyrrolnitrin and pyoluteorin-producing Pseudomonas and Burkholderia spp

    NARCIS (Netherlands)

    Souza, J.T.; Raaijmakers, J.M.

    2003-01-01

    Pyrrolnitrin (PRN) and pyoluteorin (PLT) are broad-spectrum antibiotics produced by several strains of Pseudomonas and Burkholderia species. Both antibiotics play an important role in the suppression of multiple plant pathogenic fungi. Primers were developed from conserved sequences and amplified

  8. Sensitivity of antibiotic resistant and antibiotic susceptible Escherichia coli, Enterococcus and Staphylococcus strains against ozone.

    Science.gov (United States)

    Heß, Stefanie; Gallert, Claudia

    2015-12-01

    Tolerance of antibiotic susceptible and antibiotic resistant Escherichia coli, Enterococcus and Staphylococcus strains from clinical and wastewater samples against ozone was tested to investigate if ozone, a strong oxidant applied for advanced wastewater treatment, will affect the release of antibiotic resistant bacteria into the aquatic environment. For this purpose, the resistance pattern against antibiotics of the mentioned isolates and their survival after exposure to 4 mg/L ozone was determined. Antibiotic resistance (AR) of the isolates was not correlating with higher tolerance against ozone. Except for ampicillin resistant E. coli strains, which showed a trend towards increased resistance, E. coli strains that were also resistant against cotrimoxazol, ciprofloxacin or a combination of the three antibiotics were similarly or less resistant against ozone than antibiotic sensitive strains. Pigment-producing Enterococcus casseliflavus and Staphylococcus aureus seemed to be more resistant against ozone than non-pigmented species of these genera. Furthermore, aggregation or biofilm formation apparently protected bacteria in subsurface layers from inactivation by ozone. The relatively large variance of tolerance against ozone may indicate that resistance to ozone inactivation most probably depends on several factors, where AR, if at all, does not play a major role.

  9. Induced tolerance to nebulized colistin after severe reaction to the drug.

    Science.gov (United States)

    Domínguez-Ortega, J; Manteiga, E; Abad-Schilling, C; Juretzcke, M A; Sánchez-Rubio, J; Kindelan, C

    2007-01-01

    Daily nebulized colistin therapy has been used as maintenance therapy for patients with chronic Pseudomonas aeruginosa infection and in treatment protocols aimed at eradicating early P aeruginosa infection. Colistin-induced nephrotoxicity and mild neurotoxic effects have been described but hypersensitivity reactions are rare. However, bronchial constriction has been reported associated with the inhalation of the antibiotic. We report the case of a 63-year-old man who had been diagnosed with bronchiectasis and bronchopleural fistula and who developed severe bronchospasm when using nebulized colistin. A skin prick test (80 mg/mL) with colistin was performed and was negative. An intradermal test was not performed due to its possible irritant effect. As our patient suffered from a tobramycin-resistant P aeruginosa infection, we started a procedure to induce tolerance to 80 mg colistin (8 mg, 16 mg, 24 mg, 32 mg, 40 mg, 80 mg) nebulized in 30-minutes-intervals. No changes in forced expiratory volume in 1 second values were observed and the patient continues on treatment twice daily after the tolerance induction with no new episodes of bronchospasm. We report the first successful procedure to induce tolerance to colistin after escalating doses of inhaled colistin.

  10. Tolerability and Pharmacokinetic Evaluation of Inhaled Dry Powder Tobramycin Free Base in Non-Cystic Fibrosis Bronchiectasis Patients

    NARCIS (Netherlands)

    Hoppentocht, Marcel; Akkerman, Onno W.; Hagedoorn, Paul; Alffenaar, Jan-Willem C.; van der Werf, Tjip S.; Kerstjens, Huib A. M.; Frijlink, Henderik W.; de Boer, Anne H.

    2016-01-01

    Rationale Bronchiectasis is a condition characterised by dilated and thick-walled bronchi. The presence of Pseudomonas aeruginosa in bronchiectasis is associated with a higher hospitalisation frequency and a reduced quality of life, requiring frequent and adequate treatment with antibiotics.

  11. Antibiotic resistance pattern in uropathogens

    Directory of Open Access Journals (Sweden)

    Gupta V

    2002-01-01

    Full Text Available Uropathogenic strains from inpatient and outpatient departments were studied from April 1997 to March 1999 for their susceptibility profiles. The various isolates were Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Acinetobacter baumanii and Enterococcus faecalis. Antibiotic susceptibility pattern of these isolates revealed that for outpatients, first generation cephalosporins, nitrofurantoin, norfloxacin/ciprofloxacin were effective for treatment of urinary tract infection but for inpatients, parenteral therapy with newer aminoglycosides and third generation cephalosporins need to be advocated as the organisms for nosocomial UTI exhibit a high degree of drug resistance. Trimethoprim and sulphamethoxazole combination was not found to be effective for the treatment of urinary tract infections as all the uropathogens from inpatients and outpatients showed high degree of resistance to co-trimoxazole. Culture and sensitivity of the isolates from urine samples should be done as a routine before advocating the therapy.

  12. Elongation factor P is dispensable in Escherichia coli and Pseudomonas aeruginosa.

    Science.gov (United States)

    Balibar, Carl J; Iwanowicz, Dorothy; Dean, Charles R

    2013-09-01

    Elongation factor P (EF-P) is a highly conserved ribosomal initiation factor responsible for stimulating formation of the first peptide bond. Its essentiality has been debated and may differ depending on the organism. Here, we demonstrate that EF-P is dispensable in Escherichia coli and Pseudomonas aeruginosa under laboratory growth conditions. Although knockouts are viable, growth rates are diminished compared with wild-type strains. Despite this cost in fitness, these mutants are not more susceptible to a wide range of antibiotics; including ribosome targeting antibiotics, such as lincomycin, chloramphenicol, and streptomycin, which have been shown previously to disrupt EF-P function in vitro. In Pseudomonas, knockout of efp leads to an upregulation of mexX, a phenotype previously observed with other genetic lesions affecting ribosome function and that can be induced by the treatment with antibiotics affecting protein synthesis.

  13. Isolation of Pseudomonas cepacia in cystic fibrosis patient

    Directory of Open Access Journals (Sweden)

    Elizabeth de Andrade Marques

    1993-03-01

    Full Text Available Pulmonary infection on cystic fibrosis (CF patients are associated with a limited qualitative number of microorganisms. During the colonization process, Staphylococcus aureus usually preceedes Pseudomonas aeruginosa. This latter is at first non-mucoid, being replaced or associated to a mucoid morphotype which is rare in other diseases. In 1980, Pseudomonas cepacia appeared as an important agent in CF pulmonary infections with a mean frequency of about 6.1% isolations in different parts of the world. The primus colonization mainly occurs in the presence of pre-existent tissue lesions and the clinical progress of the disease is variable. In some patients it can be fulminant; in others it can cause a gradual and slow decrease in their pulmonary functions. The concern with this germ isolation is justified by its antibiotic multiple resistence and the possibility of direct transmission from a colonized patient to a non-colonized one. We reported the first case of P. cepacia infection in a CF patient in our area. The microbiological attendance to this patient had been made from 1986 to 1991 and the first positive culture appeared in 1988. The sensitivity profile showed that the primus colonization strain was sensitive to 9 of 17 tested antibiotics, however in the last culture the strain was resistent to all antibiotics. These data corroborate the need for monitoring the bacterial flora on CF patients respiratory system.

  14. Home intravenous antibiotic therapy in children with cystic fibrosis: clinical outcome, quality of life and economic benefit

    OpenAIRE

    Chrysochoou, EA; Hatziagorou, E; Kirvassilis, F; Tsanakas, J

    2016-01-01

    Background: Pediatric home care has improved therapeutic options for children with chronic disease. Home intravenous (IV) antibiotic treatment against Pseudomonas aeruginosa (PsA) in cystic fibrosis (CF) patients has offered increased flexibility to these patients and family life. A prospective clinical study was conducted to compare safety, efficacy, and cost benefits of home versus hospital IV antibiotic treatment among CF children and adolescents.

  15. Genetic Diversity of Nitrogen-Fixing and Plant Growth Promoting Pseudomonas Species Isolated from Sugarcane Rhizosphere.

    Science.gov (United States)

    Li, Hai-Bi; Singh, Rajesh K; Singh, Pratiksha; Song, Qi-Qi; Xing, Yong-Xiu; Yang, Li-Tao; Li, Yang-Rui

    2017-01-01

    The study was designed to isolate and characterize Pseudomonas spp. from sugarcane rhizosphere, and to evaluate their plant- growth- promoting (PGP) traits and nitrogenase activity. A biological nitrogen-fixing microbe has great potential to replace chemical fertilizers and be used as a targeted biofertilizer in a plant. A total of 100 isolates from sugarcane rhizosphere, belonging to different species, were isolated; from these, 30 isolates were selected on the basis of preliminary screening, for in vitro antagonistic activities against sugarcane pathogens and for various PGP traits, as well as nitrogenase activity. The production of IAA varied from 312.07 to 13.12 μg mL -1 in tryptophan supplemented medium, with higher production in AN15 and lower in CN20 strain. The estimation of ACC deaminase activity, strains CY4 and BA2 produced maximum and minimum activity of 77.0 and 15.13 μmoL mg -1 h -1 . For nitrogenase activity among the studied strains, CoA6 fixed higher and AY1 fixed lower in amounts (108.30 and 6.16 μmoL C 2 H 2 h -1 mL -1 ). All the strains were identified on the basis of 16S rRNA gene sequencing, and the phylogenetic diversity of the strains was analyzed. The results identified all strains as being similar to Pseudomonas spp. Polymerase chain reaction (PCR) amplification of nifH and antibiotic genes was suggestive that the amplified strains had the capability to fix nitrogen and possessed biocontrol activities. Genotypic comparisons of the strains were determined by BOX, ERIC, and REP PCR profile analysis. Out of all the screened isolates, CY4 ( Pseudomonas koreensis ) and CN11 ( Pseudomonas entomophila ) showed the most prominent PGP traits, as well as nitrogenase activity. Therefore, only these two strains were selected for further studies; Biolog profiling; colonization through green fluorescent protein (GFP)-tagged bacteria; and nifH gene expression using quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The Biolog

  16. Small Rna Regulatory Networks In Pseudomonas Putida

    DEFF Research Database (Denmark)

    Bojanovic, Klara; Long, Katherine

    2015-01-01

    chemicals and has a potential to be used as an efficient cell factory for various products. P. putida KT2240 is a genome-sequenced strain and a well characterized pseudomonad. Our major aim is to identify small RNA molecules (sRNAs) and their regulatory networks. A previous study has identified 37 sRNAs...... in this strain, while in other pseudomonads many more sRNAs have been found so far.P. putida KT2440 has been grown in different conditions which are likely to be encountered in industrial fermentations with the aim of using sRNAs for generation of improved cell factories. For that, cells have been grown in LB......Pseudomonas putida is a ubiquitous Gram-negative soil bacterium with a versatile metabolism and ability to degrade various toxic compounds. It has a high tolerance to different future biobased building blocks and various other stringent conditions. It is used in industry to produce some important...

  17. Antibiotic Resistance

    DEFF Research Database (Denmark)

    Hansen, Malene Plejdrup; Hoffmann, Tammy C; McCullough, Amanda R

    2015-01-01

    hygiene, and possibly vaccination and exercise, may be effective. Also, a large range of complementary and alternative medicines (e.g. zinc, vitamin C and probiotics) are proposed for preventing and treating ARIs, but evidence for efficacy is scarce. General practitioners' (GPs) attitudes towards...... wrong. Shared decision making might be a solution, as it enables clinician and patient to participate jointly in making a health decision, having discussed the options together with the evidence for their harms as well as benefits. Furthermore, GPs' diagnostic uncertainty - often leading...... will greatly improve the use of antibiotics for ARIs. However, used in concert, combinations are likely to enable clinicians and health care systems to implement the strategies that will reduce antimicrobial resistance in the future....

  18. 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

  19. Pharmaceutical Approaches to Target Antibiotic Resistance Mechanisms.

    Science.gov (United States)

    Schillaci, Domenico; Spanò, Virginia; Parrino, Barbara; Carbone, Anna; Montalbano, Alessandra; Barraja, Paola; Diana, Patrizia; Cirrincione, Girolamo; Cascioferro, Stella

    2017-10-26

    There is urgent need for new therapeutic strategies to fight the global threat of antibiotic resistance. The focus of this Perspective is on chemical agents that target the most common mechanisms of antibiotic resistance such as enzymatic inactivation of antibiotics, changes in cell permeability, and induction/activation of efflux pumps. Here we assess the current landscape and challenges in the treatment of antibiotic resistance mechanisms at both bacterial cell and community levels. We also discuss the potential clinical application of chemical inhibitors of antibiotic resistance mechanisms as add-on treatments for serious drug-resistant infections. Enzymatic inhibitors, such as the derivatives of the β-lactamase inhibitor avibactam, are closer to the clinic than other molecules. For example, MK-7655, in combination with imipenem, is in clinical development for the treatment of infections caused by carbapenem-resistant Enterobacteriaceae and Pseudomonas aeruginosa, which are difficult to treat. In addition, other molecules targeting multidrug-resistance mechanisms, such as efflux pumps, are under development and hold promise for the treatment of multidrug resistant infections.

  20. 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.

  1. Predictors of Pseudomonas and methicillin-resistant Staphylococcus aureus in hospitalized patients with healthcare-associated pneumonia.

    Science.gov (United States)

    Metersky, Mark L; Frei, Christopher R; Mortensen, Eric M

    2016-01-01

    Patients with healthcare-associated pneumonia (HCAP) are at high risk of infection with multidrug-resistant (MDR) pathogens. Factors discriminating infection with MDR Gram-negative (MDR-GN) organism from infection with methicillin-resistant Staphylococcus aureus (MRSA) are not well understood and patients are often treated for both organisms. This study was performed to determine risk factors predicting pneumonia due to Pseudomonas versus MRSA. Veterans age ≥65 hospitalized with HCAP between 2002 and 2012 were identified from the Veterans Affairs administrative databases. Patients were identified with Pseudomonas pneumonia, MRSA pneumonia or neither according to the International Classification of Diseases, 9th Revision, Clinical Modification codes. We assessed unadjusted and adjusted associations of patient characteristics and HCAP due to Pseudomonas or MRSA. Of the 61,651 patients with HCAP, 1156 (1.9%) were diagnosed with Pseudomonas pneumonia, 641 (1.0%) with MRSA pneumonia and 59,854 (97.1%) with neither. MRSA pneumonia was positively associated with male gender, age >74, diabetes, chronic obstructive pulmonary disease (COPD), recent nursing home or hospital stay, recent exposure to fluoroquinolone or antibiotics treating Gram-positive organisms, and severe pneumonia. MRSA pneumonia was negatively associated with complicated diabetes. Pseudomonas pneumonia was positively associated with recent hospital stay, immunocompromise, COPD, hemiplegia, recent exposure to inhaled corticosteroids, β-lactam/cephalosporin/carbapenem antibiotics, antibiotics against Gram-positive organisms, 'other antibiotics' and severe pneumonia. Pseudomonas pneumonia was negatively associated with age >84, higher socioeconomic status, drug abuse and diabetes. Patient characteristics may assist in identifying patients at risk for HCAP due to Pseudomonas or MRSA. © 2015 Asian Pacific Society of Respirology.

  2. ANTAGONISTIC POTENTIAL OF FLUORESCENT Pseudomonas ...

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    GROWTH OF TOMATO CHALLENGED WITH PHTOPATHOGENS ... This study focused on the antagonistic potential of fluorescent Pseudomonas in vitro, and its inoculation effect on growth .... the 5 days old culture in starch agar with Lugol's.

  3. D-BMAP18 antimicrobial peptide is active in vitro, resists to pulmonary proteases but loses its activity in a murine model of Pseudomonas aeruginosa lung infection.

    Science.gov (United States)

    Mardirossian, Mario; Pompilio, Arianna; Degasperi, Margherita; Runti, Giulia; Pacor, Sabrina; Di Bonaventura, Giovanni; Scocchi, Marco

    2017-06-01

    The spread of antibiotic resistant-pathogens is driving the search for new antimicrobial compounds. Pulmonary infections experienced by cystic fibrosis patients are a dramatic example of this health-care emergency. Antimicrobial peptides could answer the need for new antibiotics but translating them from basic research to the clinic is a challenge. We have previously evaluated the potential of the small membranolytic peptide BMAP-18 to treat CF-related infections, discovering that while this molecule had a good activity in vitro it was not active in vivo because of its rapid degradation by pulmonary proteases. In this study, we synthesized and tested the proteases-resistant all-D enantiomer. In spite of a good antimicrobial activity against Pseudomonas aeruginosa and Stenotrophomonas maltophilia clinical isolates and of a tolerable cytotoxicity in vitro, D-BMAP18 was ineffective to treat P. aeruginosa pulmonary infection in mice, in comparison to tobramycin. We observed that different factors other than peptide degradation hampered its efficacy for pulmonary application. These results indicate that D-BMAP18 needs further optimization before being suitable for clinical application and this approach may represent a guide for optimization of other anti-infective peptides eligible for the treatment of pulmonary infections.

  4. Antimicrobial activity of beta-lactams against multiresistant micro-organisms from the family Enterobacteriaceae, and genus Pseudomonas.

    Science.gov (United States)

    Niebla, A; González, I; Vallín, C

    1994-01-01

    The antimicrobial activity of twenty beta-lactams was determined against multiresistant micro-organisms from the Enterobacteriaceae family (450) and the genus Pseudomonas (90). The antimicrobial susceptibility was assessed by the disk diffusion method. The most effective antibiotics were cephalosporins of the second and third generation, and non-classical beta-lactams (imipenem and moxalactam). A pronounced resistance was found to carbenicillin, ampicillin, cephalotin and cefazolin. These resistance patterns corresponded to a high consumption of these antibiotics.

  5. Pseudomonas aeruginosa Biofilms

    DEFF Research Database (Denmark)

    Alhede, Maria; Bjarnsholt, Thomas; Givskov, Michael

    2014-01-01

    biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling...... mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes...

  6. Inhaled antibiotics for lower airway infections.

    Science.gov (United States)

    Quon, Bradley S; Goss, Christopher H; Ramsey, Bonnie W

    2014-03-01

    Inhaled antibiotics have been used to treat chronic airway infections since the 1940s. The earliest experience with inhaled antibiotics involved aerosolizing antibiotics designed for parenteral administration. These formulations caused significant bronchial irritation due to added preservatives and nonphysiologic chemical composition. A major therapeutic advance took place in 1997, when tobramycin designed for inhalation was approved by the U.S. Food and Drug Administration (FDA) for use in patients with cystic fibrosis (CF) with chronic Pseudomonas aeruginosa infection. Attracted by the clinical benefits observed in CF and the availability of dry powder antibiotic formulations, there has been a growing interest in the use of inhaled antibiotics in other lower respiratory tract infections, such as non-CF bronchiectasis, ventilator-associated pneumonia, chronic obstructive pulmonary disease, mycobacterial disease, and in the post-lung transplant setting over the past decade. Antibiotics currently marketed for inhalation include nebulized and dry powder forms of tobramycin and colistin and nebulized aztreonam. Although both the U.S. Food and Drug Administration and European Medicines Agency have approved their use in CF, they have not been approved in other disease areas due to lack of supportive clinical trial evidence. Injectable formulations of gentamicin, tobramycin, amikacin, ceftazidime, and amphotericin are currently nebulized "off-label" to manage non-CF bronchiectasis, drug-resistant nontuberculous mycobacterial infections, ventilator-associated pneumonia, and post-transplant airway infections. Future inhaled antibiotic trials must focus on disease areas outside of CF with sample sizes large enough to evaluate clinically important endpoints such as exacerbations. Extrapolating from CF, the impact of eradicating organisms such as P. aeruginosa in non-CF bronchiectasis should also be evaluated.

  7. Demographics of antibiotic persistence

    DEFF Research Database (Denmark)

    Kollerova, Silvia; Jouvet, Lionel; Steiner, Ulrich

    Persister cells, cells that can survive antibiotic exposure but lack heritable antibiotic resistance, are assumed to play a crucial role for the evolution of antibiotic resistance. Persistence is a stage associated with reduced metabolic activity. Most previous studies have been done on batch...... even play a more prominent role for the evolution of resistance and failures of medical treatment by antibiotics as currently assumed....

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Pseudomonas aeruginosa Biofilm Infections

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  10. Sugar-Grafted Cyclodextrin Nanocarrier as a "Trojan Horse" for Potentiating Antibiotic Activity.

    Science.gov (United States)

    Li, Min; Neoh, Koon Gee; Xu, Liqun; Yuan, Liang; Leong, David Tai; Kang, En-Tang; Chua, Kim Lee; Hsu, Li Yang

    2016-05-01

    The use of "Trojan Horse" nanocarriers for antibiotics to enhance the activity of antibiotics against susceptible and resistant bacteria is investigated. Antibiotic carriers (CD-MAN and CD-GLU) are prepared from β-cyclodextrin grafted with sugar molecules (D-mannose and D-glucose, respectively) via azide-alkyne click reaction. The sugar molecules serve as a chemoattractant enticing the bacteria to take in higher amounts of the antibiotic, resulting in rapid killing of the bacteria. Three types of hydrophobic antibiotics, erythromycin, rifampicin and ciprofloxacin, are used as model drugs and loaded into the carriers. The minimum inhibitory concentration of the antibiotics in the CD-MAN-antibiotic and CD-GLU-antibiotic complexes for Gram-negative Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii strains, and a number of Gram-positive Staphylococcus aureus strains, including the methicillin-resistant strains (MRSA), are reduced by a factor ranging from 3 to >100. The CD-MAN-antibiotic complex is also able to prolong the stability of the loaded antibiotic and inhibit development of intrinsic antibiotic resistance in the bacteria. These non-cytotoxic sugar-modfied nanocarriers can potentiate the activity of existing antibiotics, especially against multidrug-resistant bacteria, which is highly advantageous in view of the paucity of new antibiotics in the pipeline.

  11. Biodegradation of propargite by Pseudomonas putida, isolated from tea rhizosphere.

    Science.gov (United States)

    Sarkar, Soumik; Seenivasan, Subbiah; Asir, Robert Premkumar Samuel

    2010-02-15

    Biodegradation of miticide propargite was carried out in vitro by selected Pseudomonas strains isolated from tea rhizosphere. A total number of 13 strains were isolated and further screened based on their tolerance level to different concentrations of propargite. Five best strains were selected and further tested for their nutritional requirements. Among the different carbon sources tested glucose exhibited the highest growth promoting capacity and among nitrogen sources ammonium nitrate supported the growth to the maximum. The five selected Pseudomonas strain exhibited a range of degradation capabilities. Mineral salts medium (MSM) amended with glucose provided better environment for degradation with the highest degradation potential in strain SPR 13 followed by SPR 8 (71.9% and 69.0% respectively).

  12. Pseudomonas and Beyond : Polyamine metabolism, lignin degradation and potential applications in industrial biotechnology

    NARCIS (Netherlands)

    Bandounas, L.

    2011-01-01

    Renewable resources such as lignocellulosic biomass are promising feedstocks for the production of bio-fuels and value-added products. Biocatalysts are considered important tools in such processes. Pseudomonas putida S12 has a broad metabolic potential and is exceptionally tolerant towards a range

  13. Experimental investigation of activities and tolerance of denitrifying bacteria under alkaline and reducing condition

    International Nuclear Information System (INIS)

    Mine, Tatsuya; Mihara, Morihiro; Ooi, Takao

    2000-07-01

    In the geological disposal system of TRU wastes, nitrogen generation by denitrifying bacteria could provide significant impact on the assessment of this system, because nitrate contained in process concentrated liquid waste might be electron acceptor for denitrifying bacteria. In this study, the activities and tolerance of denitrifying under disposal condition were investigated. Pseudomonas denitrificans as denitrifying bacteria was used. The results showed that Pseudomonas denitrificans had activity under reducing condition, but under high pH condition (pH>9.5), the activity of Pseudomonas denitrificans was not detected. It is possible that the activity of Pseudomonas denitrificans would be low under disposal condition. (author)

  14. Optimising the duration of antibiotic therapy for ventilator-associated pneumonia

    Directory of Open Access Journals (Sweden)

    J. Chastre

    2007-08-01

    Full Text Available Ventilator-associated pneumonia (VAP has traditionally been treated with a 14–21-day course of antibiotics. However, prolonged antibiotic therapy is associated with the emergence of multidrug-resistant strains, as well as higher toxicity and costs. In a large, randomised, controlled trial in patients with microbiologically confirmed VAP who received appropriate empirical antibiotic therapy, an 8-day antibiotic regimen was not associated with excess mortality or more episodes of recurrent pulmonary infection compared with a 15-day regimen. Amongst patients who developed recurrent infection, multidrug-resistant pathogens emerged less frequently in the group receiving 8 days of antibiotic therapy. The 8-day regimen was also not associated with excess mortality in the subgroup with VAP caused by nonfermentative Gram-negative bacilli, mostly Pseudomonas aeruginosa, although recurrent infections occurred more often. Pending confirmatory studies, an 8-day course of antibiotic therapy may be appropriate for many patients with ventilator-associated pneumonia, providing that initial antibiotic therapy is appropriate, the clinical course is favourable and extreme vigilance is maintained after stopping antibiotics. Patients whose initial treatment regimen was inappropriate, those infected with difficult-to-treat pathogens such as Pseudomonas aeruginosa, and immunocompromised patients and others at high risk for relapse are likely to require a longer duration of antibiotic therapy.

  15. Biosurfactant production by Pseudomonas strains isolated from floral nectar.

    Science.gov (United States)

    Ben Belgacem, Z; Bijttebier, S; Verreth, C; Voorspoels, S; Van de Voorde, I; Aerts, G; Willems, K A; Jacquemyn, H; Ruyters, S; Lievens, B

    2015-06-01

    To screen and identify biosurfactant-producing Pseudomonas strains isolated from floral nectar; to characterize the produced biosurfactants; and to investigate the effect of different carbon sources on biosurfactant production. Four of eight nectar Pseudomonas isolates were found to produce biosurfactants. Phylogenetic analysis based on three housekeeping genes (16S rRNA gene, rpoB and gyrB) classified the isolates into two groups, including one group closely related to Pseudomonas fluorescens and another group closely related to Pseudomonas fragi and Pseudomonas jessenii. Although our nectar pseudomonads were able to grow on a variety of water-soluble and water-immiscible carbon sources, surface active agents were only produced when using vegetable oil as sole carbon source, including olive oil, sunflower oil or waste frying sunflower oil. Structural characterization based on thin layer chromatography (TLC) and ultra high performance liquid chromatography-accurate mass mass spectrometry (UHPLC-amMS) revealed that biosurfactant activity was most probably due to the production of fatty acids (C16:0; C18:0; C18:1 and C18:2), and mono- and diglycerides thereof. Four biosurfactant-producing nectar pseudomonads were identified. The active compounds were identified as fatty acids (C16:0; C18:0; C18:1 and C18:2), and mono- and diglycerides thereof, produced by hydrolysis of triglycerides of the feedstock. Studies on biosurfactant-producing micro-organisms have mainly focused on microbes isolated from soils and aquatic environments. Here, for the first time, nectar environments were screened as a novel source for biosurfactant producers. As nectars represent harsh environments with high osmotic pressure and varying pH levels, further screening of nectar habitats for biosurfactant-producing microbes may lead to the discovery of novel biosurfactants with broad tolerance towards different environmental conditions. © 2015 The Society for Applied Microbiology.

  16. Exacerbation of bronchiectasis by Pseudomonas monteilii: a case report.

    Science.gov (United States)

    Aditi; Shariff, Malini; Beri, Kiran

    2017-07-24

    Pseudomonas spp are important opportunistic and nosocomial pathogens. One such species is Pseudomonas monteilii (P. monteilii). It has been described as an environmental contaminant and potential pathogen. We identified this organism as the causative agent of an exacerbation of bronchiectasis and an environmental contaminant in our hospital on two separate occasions. P. monteilii was the cause of an exacerbation of bronchiectasis in a 30-year-old HIV negative male. Patient presented with cough with sputum production and exertional dyspnea. The isolate was recovered from a sputum sample in significant counts and definitively identified by Matrix-Assisted Laser Desorption/Ionisation- Time of Flight Mass Spectrometry (MALDI-TOF MS). He was treated with piperacillin-tazobactam and recovered clinically and microbiologically. Another two isolates of the organism were contaminants from the hospital environment. The three isolates were susceptible to all tested antibiotics. Typing by Random amplification of polymorphic DNA (RAPD) found no clonal relationship between them. Less common species of Pseudomonas need to be identified accurately. This organism is identified by commonly used phenotypic systems as P. putida which may have contributed to a lower reported prevalence. P. monteilii is a known environmental contaminant and must also be considered as a potential pathogen, particularly in patients with chronic lung disease.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Garry Laverty

    2014-07-01

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

  19. Heavy metal driven co-selection of antibiotic resistance in soil and water bodies impacted by agriculture and aquaculture

    OpenAIRE

    Seiler, Claudia; Berendonk, Thomas U.

    2012-01-01

    The use of antibiotic agents as growth promoters was banned in animal husbandry to prevent the selection and spread of antibiotic resistance. However, in addition to antibiotic agents, heavy metals used in animal farming and aquaculture might promote the spread of antibiotic resistance via co-selection. To investigate which heavy metals are likely to co-select for antibiotic resistance in soil and water, the available data on heavy metal pollution, heavy metal toxicity, heavy metal tolerance ...

  20. 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.

  1. Conjugative type IVb pilus recognizes lipopolysaccharide of recipient cells to initiate PAPI-1 pathogenicity island transfer in Pseudomonas aeruginosa

    Science.gov (United States)

    Pseudomonas aeruginosa pathogenicity island 1 (PAPI-1) is one of the largest genomic islands of this important opportunistic human pathogen. Previous studies have shown that PAPI-1 encodes several putative virulence factors, a major regulator of biofilm formation, and antibiotic-resistance traits, a...

  2. Phloroglucinol mediates crosstalk between the pyoluteorin and 2,4-diacetylphloroglucinol biosynthetic pathways in Pseudomonas fluorescens Pf-5

    Science.gov (United States)

    The antibiotics pyoluteorin and 2,4-diacetylphloroglucinol (DAPG) are involved in the biological control of certain soil-borne diseases by some strains of Pseudomonas fluorescens, including P. fluorescens Pf-5. These secondary metabolites also act as signaling molecules with each compound reported ...

  3. 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.

  4. Assessment of DAPG-producing Pseudomonas fluorescens for management of Meloidogyne incognita and Fusarium oxysporum on watermelon

    Science.gov (United States)

    Pseudomonas fluorescens isolates Clinto 1R, Wayne 1R and Wood 1R, which produce the antibiotic 2,4-diacetylphloroglucinol (DAPG), can suppress soilborne diseases and promote plant growth. Consequently, these beneficial bacterial isolates were tested on watermelon plants for suppression of Meloidogy...

  5. Draft Genome Sequence of an Invasive Multidrug-Resistant Strain, Pseudomonas aeruginosa BK1, Isolated from a Keratitis Patient

    KAUST Repository

    Jeganathan, Lakshmi Priya

    2014-03-27

    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, isolated from a bacterial keratitis patient in southern India.

  6. 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

  7. Amikacin loaded PLGA nanoparticles against Pseudomonas aeruginosa.

    Science.gov (United States)

    Sabaeifard, Parastoo; Abdi-Ali, Ahya; Soudi, Mohammad Reza; Gamazo, Carlos; Irache, Juan Manuel

    2016-10-10

    Amikacin is a very effective aminoglycoside antibiotic but according to its high toxicity, the use of this antibiotic has been limited. The aim of this study was to formulate and characterize amikacin loaded PLGA nanoparticles. Nanoparticles were synthetized using a solid-in-oil-in-water emulsion technique with different ratio of PLGA 50:50 (Resomer 502H) to drug (100:3.5, 80:3.5 and 60:3.5), two different concentrations of stabilizer (pluronic F68) (0.5% or 1%) and varied g forces to recover the final products. The most efficient formulation based on drug loading (26.0±1.3μg/mg nanoparticle) and encapsulation efficiency (76.8±3.8%) was the one obtained with 100:3.5 PLGA:drug and 0.5% luronic F68, recovered by 20,000×g for 20min. Drug release kinetic study indicated that about 50% of the encapsulated drug was released during the first hour of incubation in phospahte buffer, pH7.4, 37°C, 120rpm. Using different cell viability/cytotoxicity assays, the optimized formulation showed no toxicity against RAW macrophages after 2 and 24h of exposure. Furthermore, released drug was active and maintained its bactericidal activity against Pseudomonas aeruginosa in vitro. These results support the effective utilization of the PLGA nanoparticle formulation for amikacin in further in vivo studies. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Physiology of solvent tolerance in Pseudomonas putida S12

    NARCIS (Netherlands)

    Isken, S.

    2000-01-01

    Hydrophobic organic solvents, like toluene, are toxic for living organisms. This toxicity is an important drawback in the environmental biotechnology as well as in the application of solvents in the production of fine chemicals by whole-cell biotransformations. The effects of organic

  9. Inhaled Antibiotic Therapy in Chronic Respiratory Diseases

    Directory of Open Access Journals (Sweden)

    Diego J. Maselli

    2017-05-01

    Full Text Available The management of patients with chronic respiratory diseases affected by difficult to treat infections has become a challenge in clinical practice. Conditions such as cystic fibrosis (CF and non-CF bronchiectasis require extensive treatment strategies to deal with multidrug resistant pathogens that include Pseudomonas aeruginosa, Methicillin-resistant Staphylococcus aureus, Burkholderia species and non-tuberculous Mycobacteria (NTM. These challenges prompted scientists to deliver antimicrobial agents through the pulmonary system by using inhaled, aerosolized or nebulized antibiotics. Subsequent research advances focused on the development of antibiotic agents able to achieve high tissue concentrations capable of reducing the bacterial load of difficult-to-treat organisms in hosts with chronic respiratory conditions. In this review, we focus on the evidence regarding the use of antibiotic therapies administered through the respiratory system via inhalation, nebulization or aerosolization, specifically in patients with chronic respiratory diseases that include CF, non-CF bronchiectasis and NTM. However, further research is required to address the potential benefits, mechanisms of action and applications of inhaled antibiotics for the management of difficult-to-treat infections in patients with chronic respiratory diseases.

  10. Redox-Active Antibiotics Control Gene Expression and Community Behavior in Divergent Bacteria

    OpenAIRE

    Dietrich, Lars E. P.; Teal, Tracy K.; Price-Whelan, Alexa; Newman, Dianne K.

    2008-01-01

    It is thought that bacteria excrete redox-active pigments as antibiotics to inhibit competitors. In Pseudomonas aeruginosa, the endogenous antibiotic pyocyanin activates SoxR, a transcription factor conserved in Proteo- and Actinobacteria. In Escherichia coli, SoxR regulates the superoxide stress response. Bioinformatic analysis coupled with gene expression studies in P. aeruginosa and Streptomyces coelicolor revealed that the majority of SoxR regulons in bacteria lack the genes required for ...

  11. A case of orbital apex syndrome due to Pseudomonas aeruginosa infection

    Directory of Open Access Journals (Sweden)

    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.

  12. 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...

  13. Sinonasal inhalation of tobramycin vibrating aerosol in cystic fibrosis patients with upper airway Pseudomonas aeruginosa colonization: results of a randomized, double-blind, placebo-controlled pilot study

    Science.gov (United States)

    Mainz, Jochen G; Schädlich, Katja; Schien, Claudia; Michl, Ruth; Schelhorn-Neise, Petra; Koitschev, Assen; Koitschev, Christiane; Keller, Peter M; Riethmüller, Joachim; Wiedemann, Baerbel; Beck, James F

    2014-01-01

    Rationale In cystic fibrosis (CF), the paranasal sinuses are sites of first and persistent colonization by pathogens such as Pseudomonas aeruginosa. Pathogens subsequently descend to the lower airways, with P. aeruginosa remaining the primary cause of premature death in patients with the inherited disease. Unlike conventional aerosols, vibrating aerosols applied with the PARI Sinus™ nebulizer deposit drugs into the paranasal sinuses. This trial assessed the effects of vibrating sinonasal inhalation of the antibiotic tobramycin in CF patients positive for P. aeruginosa in nasal lavage. Objectives To evaluate the effects of sinonasal inhalation of tobramycin on P. aeruginosa quantification in nasal lavage; and on patient quality of life, measured with the Sino-Nasal Outcome Test (SNOT-20), and otologic and renal safety and tolerability. Methods Patients were randomized to inhalation of tobramycin (80 mg/2 mL) or placebo (2 mL isotonic saline) once daily (4 minutes/nostril) with the PARI Sinus™ nebulizer over 28 days, with all patients eligible for a subsequent course of open-label inhalation of tobramycin for 28 days. Nasal lavage was obtained before starting and 2 days after the end of each treatment period by rinsing each nostril with 10 mL of isotonic saline. Results Nine patients participated, six initially receiving tobramycin and three placebo. Sinonasal inhalation was well tolerated, with serum tobramycin <0.5 mg/L and stable creatinine. P. aeruginosa quantity decreased in four of six (67%) patients given tobramycin, compared with zero of three given placebo (non-significant). SNOT-20 scores were significantly lower in the tobramycin than in the placebo group (P=0.033). Conclusion Sinonasal inhalation of vibrating antibiotic aerosols appears promising for reducing pathogen colonization of paranasal sinuses and for control of symptoms in patients with CF. PMID:24596456

  14. "Hot Tub Rash" and "Swimmer's Ear" (Pseudomonas)

    Science.gov (United States)

    Facts About “Hot Tub Rash” and “Swimmer’s Ear” (Pseudomonas) What is Pseudomonas and how can it affect me? Pseudomonas (sue-doh- ... a major cause of infections commonly known as “hot tub rash” and “swimmer’s ear.” This germ is ...

  15. Crafting tolerance

    DEFF Research Database (Denmark)

    Kirchner, Antje; Freitag, Markus; Rapp, Carolin

    2011-01-01

    Ongoing changes in social structures, orientation, and value systems confront us with the growing necessity to address and understand transforming patterns of tolerance as well as specific aspects, such as social tolerance. Based on hierarchical analyses of the latest World Values Survey (2005......–08) and national statistics for 28 countries, we assess both individual and contextual aspects that influence an individual's perception of different social groupings. Using a social tolerance index that captures personal attitudes toward these groupings, we present an institutional theory of social tolerance. Our...

  16. Identification of Fitness Determinants during Energy-Limited Growth Arrest in Pseudomonas aeruginosa.

    Science.gov (United States)

    Basta, David W; Bergkessel, Megan; Newman, Dianne K

    2017-11-28

    Microbial growth arrest can be triggered by diverse factors, one of which is energy limitation due to scarcity of electron donors or acceptors. Genes that govern fitness during energy-limited growth arrest and the extent to which they overlap between different types of energy limitation are poorly defined. In this study, we exploited the fact that Pseudomonas aeruginosa can remain viable over several weeks when limited for organic carbon (pyruvate) as an electron donor or oxygen as an electron acceptor. ATP values were reduced under both types of limitation, yet more severely in the absence of oxygen. Using transposon-insertion sequencing (Tn-seq), we identified fitness determinants in these two energy-limited states. Multiple genes encoding general functions like transcriptional regulation and energy generation were required for fitness during carbon or oxygen limitation, yet many specific genes, and thus specific activities, differed in their relevance between these states. For instance, the global regulator RpoS was required during both types of energy limitation, while other global regulators such as DksA and LasR were required only during carbon or oxygen limitation, respectively. Similarly, certain ribosomal and tRNA modifications were specifically required during oxygen limitation. We validated fitness defects during energy limitation using independently generated mutants of genes detected in our screen. Mutants in distinct functional categories exhibited different fitness dynamics: regulatory genes generally manifested a phenotype early, whereas genes involved in cell wall metabolism were required later. Together, these results provide a new window into how P. aeruginosa survives growth arrest. IMPORTANCE Growth-arrested bacteria are ubiquitous in nature and disease yet understudied at the molecular level. For example, growth-arrested cells constitute a major subpopulation of mature biofilms, serving as an antibiotic-tolerant reservoir in chronic

  17. Inhibition of Cell Differentiation in Bacillus subtilis by Pseudomonas protegens

    Science.gov (United States)

    Powers, Matthew J.; Sanabria-Valentín, Edgardo; Bowers, Albert A.

    2015-01-01

    ABSTRACT Interspecies interactions have been described for numerous bacterial systems, leading to the identification of chemical compounds that impact bacterial physiology and differentiation for processes such as biofilm formation. Here, we identified soil microbes that inhibit biofilm formation and sporulation in the common soil bacterium Bacillus subtilis. We did so by creating a reporter strain that fluoresces when the transcription of a biofilm-specific gene is repressed. Using this reporter in a coculture screen, we identified Pseudomonas putida and Pseudomonas protegens as bacteria that secrete compounds that inhibit biofilm gene expression in B. subtilis. The active compound produced by P. protegens was identified as the antibiotic and antifungal molecule 2,4-diacetylphloroglucinol (DAPG). Colonies of B. subtilis grown adjacent to a DAPG-producing P. protegens strain had altered colony morphologies relative to B. subtilis colonies grown next to a DAPG-null P. protegens strain (phlD strain). Using a subinhibitory concentration of purified DAPG in a pellicle assay, we saw that biofilm-specific gene transcription was delayed relative to transcription in untreated samples. These transcriptional changes also corresponded to phenotypic alterations: both biofilm biomass and spore formation were reduced in B. subtilis liquid cultures treated with subinhibitory concentrations of DAPG. Our results add DAPG to the growing list of antibiotics that impact bacterial development and physiology at subinhibitory concentrations. These findings also demonstrate the utility of using coculture as a means to uncover chemically mediated interspecies interactions between bacteria. IMPORTANCE Biofilms are communities of bacteria adhered to surfaces by an extracellular matrix; such biofilms can have important effects in both clinical and agricultural settings. To identify chemical compounds that inhibited biofilm formation, we used a fluorescent reporter to screen for bacteria that

  18. Multidrug resistance in Pseudomonas aeruginosa isolated from nosocomial respiratory and urinary infections in Aleppo, Syria.

    Science.gov (United States)

    Mahfoud, Maysa; Al Najjar, Mona; Hamzeh, Abdul Rezzak

    2015-02-19

    Pseudomonas aeruginosa represents a serious clinical challenge due to its frequent involvement in nosocomial infections and its tendency towards multidrug resistance. This study uncovered antibiotic susceptibility patterns in 177 isolates from inpatients in three key hospitals in Aleppo, the largest city in Syria. Exceptionally low susceptibility to most routinely used antibiotics was uncovered; resistance to ciprofloxacin and gentamicin was 64.9% and 70.3%, respectively. Contrarily, susceptibility to colistin was the highest (89.1%). Multidrug resistance was rife, found at a rate of 53.67% among studied P. aeruginosa isolates.

  19. A case report of acute pediatric bacterial meningitis due to the rare isolate, Pseudomonas putida

    Institute of Scientific and Technical Information of China (English)

    Grishma V. Kulkarni

    2016-01-01

    Acute bacterial meningitis (ABM) is the medical emergency which warrants an early diagnosis and an aggressive therapy. Despite the availability of the potent newer antibiotics, the mortality caused by ABM and its complications remain high in India, ranging from 16% to 32%. The aim of this case report is to present the rare isolation ofPseudomonas putida from cerebrospinal lfuid sample. Besides this, the author also emphasizes the importance of correctly identifying the organism and thus the selection of the most accurate antibiotic from the susceptibility proifle to allow for early recovery and to improve the patient outcome and survival.

  20. Probiotics and antibiotics in IBD.

    Science.gov (United States)

    Sokol, Harry

    2014-01-01

    The involvement of the gut microbiota in the pathogenesis of IBD is supported by many findings and is thus now commonly acknowledged. The imbalance in the composition of the microbiota (dysbiosis) observed in IBD patients is one of the strongest arguments and provides the rationale for a therapeutic manipulation of the gut microbiota. The tools available to achieve this goal include fecal microbiota transplantation, but antibiotics and probiotics have been the most used one until now. Although antibiotics have shown some efficacy in inducing remission in Crohn's disease (CD) and ulcerative colitis (UC), as well as preventing postoperative relapse in CD, they are not currently recommended for the treatment of IBD except for septic complications, notably because of long-term tolerance and ecological issues. Some probiotics have been shown to be as good as 5-aminosalicylic acid to maintain remission in mild-to-moderate UC, but have been disappointing until now in CD in all tested indications. In pouchitis, antibiotics and probiotics have shown efficacy for inducing and maintaining remission, respectively. Targeting the gut microbiota in IBD is an attractive strategy. Current efforts to better understand the host-microbiota interactions in physiological as well as disease settings might lead to the development of rational-based treatments. © 2014 S. Karger AG, Basel.

  1. The antibiotic resistome.

    Science.gov (United States)

    Wright, Gerard D

    2010-08-01

    Antibiotics are essential for the treatment of bacterial infections and are among our most important drugs. Resistance has emerged to all classes of antibiotics in clinical use. Antibiotic resistance has, proven inevitable and very often it emerges rapidly after the introduction of a drug into the clinic. There is, therefore, a great interest in understanding the origins, scope and evolution of antibiotic resistance. The review discusses the concept of the antibiotic resistome, which is the collection of all genes that directly or indirectly contribute to antibiotic resistance. The review seeks to assemble current knowledge of the resistome concept as a means of understanding the totality of resistance and not just resistance in pathogenic bacteria. The concept of the antibiotic resistome provides a framework for the study and understanding of how resistance emerges and evolves. Furthermore, the study of the resistome reveals strategies that can be applied in new antibiotic discoveries.

  2. 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

  3. 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: ...

  4. 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....

  5. Isolation and characterization of dihydrofolate reductase from trimethoprim-susceptible and trimethoprim-resistant Pseudomonas cepacia.

    OpenAIRE

    Burns, J L; Lien, D M; Hedin, L A

    1989-01-01

    Trimethoprim resistance was investigated in cystic fibrosis isolates of Pseudomonas cepacia. Determination of the MIC of trimethoprim for 111 strains revealed at least two populations of resistant organisms, suggesting the presence of more than one mechanism of resistance. Investigation of the antibiotic target, dihydrofolate reductase, was undertaken in both a susceptible strain and a strain with high-level resistance (MIC, greater than 1,000 micrograms/ml). The enzyme was purified by using ...

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

    OpenAIRE

    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...

  7. Isolation, Identification, and Characterization of Cadmium Resistant Pseudomonas sp. M3 from Industrial Wastewater

    OpenAIRE

    Syed Zaghum Abbas; Mohd Rafatullah; Norli Ismail; Japareng Lalung

    2014-01-01

    The present study deals with the isolation, identification, and characterization of the cadmium resistant bacteria from wastewater collected from industrial area of Penang, Malaysia. The isolate was selected based on high level of the cadmium and antibiotic resistances. On the basis of morphological, biochemical characteristics, 16S rDNA gene sequencing and phylogeny analysis revealed that the strain RZCd1 was authentically identified as Pseudomonas sp. M3. The industrial isolate showed more ...

  8. 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...

  9. 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.

  10. Increased concentration of Pseudomonas aeruginosa and Staphylococcus sp. in small animals exposed to aerospace environments

    Science.gov (United States)

    Guthrie, R. K.

    1976-01-01

    The effects of increased concentrations of PSEUDOMONAS AERUGINOSA AND STAPHYLOCOCCUS in the total bacterial flora of small animals exposed to simulated spacecraft environments were evaluated. Tests to detect changes in infectivity, effects of antibiotic treatments, immune responses to bacterial antigens, and effectiveness of immune responses in the experimental environment were conducted. The most significant results appear to be the differences in immune responses at simulated altitudes and the production of infection in the presence of a specific antibody.

  11. Know When Antibiotics Work

    Centers for Disease Control (CDC) Podcasts

    2015-04-15

    This podcast provides a brief background about antibiotics and quick tips to help prevent antibiotic resistance.  Created: 4/15/2015 by Division of Bacterial Diseases (DBD), National Center for Immunization and Respiratory Disease (NCIRD), Get Smart: Know When Antibiotics Work Program.   Date Released: 4/16/2015.

  12. Antibiotics: Miracle Drugs

    Centers for Disease Control (CDC) Podcasts

    The overuse of antibiotics has led to the development of resistance among bacteria, making antibiotics ineffective in treating certain conditions. This podcast discusses the importance of talking to your healthcare professional about whether or not antibiotics will be beneficial if you've been diagnosed with an infectious disease.

  13. 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...

  14. Frequency and antibiotic resistance patterns of isolated bacteria from positive blood culture of hospitalized patients

    Directory of Open Access Journals (Sweden)

    Azadeh Vahedi

    2018-03-01

    Conclusion: The most prevalent bacterial isolate among the blood cultures of patients was Pseudomonas. The patients more than 50 years were more susceptible to blood stream infections. The most bacteria were isolated from the internal medicine department of hospital. The antibiotic resistance was also increasing especially in Acinetobacter, Staphylococcus coagulase negative, Escherichia coil and Klebsiella

  15. THE STUDY OF ANTIBIOTIC- AND FAGOSENSITIVITY OF NOSOCOMIAL STRAINS BACTERIA ISOLATED FROM TRANSPLANTED PATIENTS

    Directory of Open Access Journals (Sweden)

    N. I. Gabrielan

    2011-01-01

    Full Text Available Antibiotic and fagosensitivity most etiologically important nosocomial strains of bacteria – Pseudomonas aeru- ginosa, Klebsiella pneumoniae, E. coli, Proteus spp., Staphylococcus spp. were studied. Multiple drug-resistant bacteria as gram-positive and gram-negative, isolated from 8 substrates, had been demonstrated. With regard to the sensitivity of Pseudomonas aeruginosa >40% was observed in 40–50% of the strains to aminoglycosides – aztreonam, amikacin, netilmicin, and only 23–25% of the strains – to gentamicin and levofloxacin (an average of antibiotic susceptibility was 27%. All strains of ESBL Klebsiella drew up and were sensitive only to imipenem, meropenem and aminoglycosides. Specific phages lysed 43–48% of the strains Pseudomonas aeruginosa and Klebsiella pneumoniae, E. coli, Pro- teus spp., multidrug resistant strains of Staphylococcus spp. It is proposed to introduce the use of phages in clinical practice. 

  16. Systemic antibiotics in periodontics.

    Science.gov (United States)

    Slots, Jørgen

    2004-11-01

    This position paper addresses the role of systemic antibiotics in the treatment of periodontal disease. Topical antibiotic therapy is not discussed here. The paper was prepared by the Research, Science and Therapy Committee of the American Academy of Periodontology. The document consists of three sections: 1) concept of antibiotic periodontal therapy; 2) efficacy of antibiotic periodontal therapy; and 3) practical aspects of antibiotic periodontal therapy. The conclusions drawn in this paper represent the position of the American Academy of Periodontology and are intended for the information of the dental profession.

  17. Antibiotic Residues - A Global Health Hazard

    Directory of Open Access Journals (Sweden)

    Nisha A.R.

    Full Text Available Use of Antibiotic that might result in deposition of residues in meat, milk and eggs must not be permitted in food intended for human consumption. If use of antibiotics is necessary as in prevention and treatment of animal diseases, a withholding period must be observed until the residues are negligible or no longer detected. The use of antibiotics to bring about improved performance in growth and feed efficiency, to synchronize or control of reproductive cycle and breeding performance also often lead to harmful residual effects. Concern over antibiotic residues in food of animal origin occurs in two times; one which produces potential threat to direct toxicity in human, second is whether the low levels of antibiotic exposure would result in alteration of microflora, cause disease and the possible development of resistant strains which cause failure of antibiotic therapy in clinical situations. A withdrawal period is established to safeguard human from exposure of antibiotic added food. The withdrawal time is the time required for the residue of toxicological concern to reach safe concentration as defined by tolerance. It is the interval from the time an animal is removed from medication until permitted time of slaughter. Heavy responsibility is placed on the veterinarian and livestock producer to observe the period for a withdrawal of a drug prior to slaughter to assure that illegal concentration of drug residue in meat, milk and egg do not occur. Use of food additives may improve feed efficiency 17% in beef cattle, 10% in lambs, 15% in poultry and 15% in swine. But their indiscriminate use will produce toxicity in consumers. WHO and FAO establish tolerances for a drug, pesticide or other chemical in the relevant tissues of food producing animals. The tolerance is the tissue concentration below, which a marker residue for the drug or chemical must fall in the target tissue before that animal edible tissues are considered safe for human

  18. Antimicrobial resistance in Pseudomonas sp. causing infections in trauma patients: A 6 year experience from a south asian country

    Directory of Open Access Journals (Sweden)

    Nonika Rajkumari

    2014-01-01

    Full Text Available Drug resistance to Pseudomonas sp. has spread to such a level irrespective of the type of patients, that its pattern of distribution and antibiotic resistance needs to be studied in detail, especially in trauma patients and hence the study. A 6 year study was carried out among trauma patients to see the trend and type of resistance prevalent in the apex hospital for trauma care in India among nonduplicate isolates where multidrug-resistance (MDR, cross-resistance and pan-drug resistance in Pseudomonas sp. were analyzed. Of the total 2,269 isolates obtained, the species, which was maximally isolated was Pseudomonas aeruginosa (2,224, 98%. The highest level of resistance was seen in tetracycline (2,166, 95.5%, P < 0.001 and chloramphenicol (2,160, 95.2%, P < 0.001 and least in meropenem (1,739, 76.7%, P < 0.003. Of the total, 1,692 (74.6% isolates were MDR in which P. aeruginosa (75% were maximum. MDR Pseudomonas is slowing increasing since the beginning of the study period. Of 1,797 imipenem-resistant P. aeruginosa isolated during the study period, 1,763 (98% showed resistance to ciprofloxacin or levofloxacin, suggesting that cross-resistance may have developed for imipenem due to prior use of fluoroquinolones. Antibiotic resistance in Pseudomonas sp. is fast becoming a problem in trauma patients, especially in those who requires prolong hospital stay, which calls for proper antimicrobial stewardship.

  19. Bacterial mediated amelioration of drought stress in drought tolerant ...

    African Journals Online (AJOL)

    yogendra

    2015-02-23

    Feb 23, 2015 ... for a beneficial effect of PGPRs application in enhancing drought tolerance of rice under water deficit conditions. ..... involvement of PGPRs in ROS metabolism in rice plants. ... osmoregulatory solute in plants (Kumar et al., 2011). ..... Pseudomonas fluorescens mediated saline resistance in groundnut.

  20. In vitro interaction between Agrimonia eupatoria L.: Extracts and antibiotic

    Directory of Open Access Journals (Sweden)

    Muruzović Mirjana Ž.

    2017-01-01

    Full Text Available Synergistic activity between water, acetone, ethanol and diethyl ether extract of Agrimonia eupatoria L. and commonly used antibiotic (ampicillin were evaluated. Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae and Pseudomonas aeruginosa were used. Interaction between plant extracts and antibiotic were tested by checkerboard method and expressed as fractional inhibitory concentration (FIC index showed indifferent, additive and synergistic effects. Synergism was observed against E. coli for every combination of agents. FICI values were ranged from 0.03 to 0.29. Inhibitory concentration (IC50 was evaluated for every combination of tested extracts and antibiotic and the best combinations for every tested bacteria were combination of diethyl ether extract + ampicillin and combination of acetone extract + ampicillin.

  1. H2S: a universal defense against antibiotics in bacteria.

    Science.gov (United States)

    Shatalin, Konstantin; Shatalina, Elena; Mironov, Alexander; Nudler, Evgeny

    2011-11-18

    Many prokaryotic species generate hydrogen sulfide (H(2)S) in their natural environments. However, the biochemistry and physiological role of this gas in nonsulfur bacteria remain largely unknown. Here we demonstrate that inactivation of putative cystathionine β-synthase, cystathionine γ-lyase, or 3-mercaptopyruvate sulfurtransferase in Bacillus anthracis, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli suppresses H(2)S production, rendering these pathogens highly sensitive to a multitude of antibiotics. Exogenous H(2)S suppresses this effect. Moreover, in bacteria that normally produce H(2)S and nitric oxide, these two gases act synergistically to sustain growth. The mechanism of gas-mediated antibiotic resistance relies on mitigation of oxidative stress imposed by antibiotics.

  2. Om tolerance

    DEFF Research Database (Denmark)

    Huggler, Jørgen

    2007-01-01

    Begrebet tolerance og dets betydninger diskuteres med henblik på en tydeliggørelse af begrebets forbindelse med stat, religion, ytringsfrihed, skeptisk erkendelsesteori, antropologi og pædagogik.......Begrebet tolerance og dets betydninger diskuteres med henblik på en tydeliggørelse af begrebets forbindelse med stat, religion, ytringsfrihed, skeptisk erkendelsesteori, antropologi og pædagogik....

  3. Alternatives to Antibiotics in Animal Agriculture: An Ecoimmunological View

    OpenAIRE

    Sang, Yongming; Blecha, Frank

    2014-01-01

    Ecological immunology (or ecoimmunology) is a new discipline in animal health and immunology that extends immunologists’ views into a natural context where animals and humans have co-evolved. Antibiotic resistance and tolerance (ART) in bacteria are manifested in antibiosis-surviving subsets of resisters and persisters. ART has emerged though natural evolutionary consequences enriched by human nosocomial and agricultural practices, in particular, wide use of antibiotics that overwhelms other ...

  4. Antibiotic-resistant bacteria in drinking water.

    Science.gov (United States)

    Armstrong, J L; Shigeno, D S; Calomiris, J J; Seidler, R J

    1981-08-01

    We analyzed drinking water from seven communities for multiply antibiotic-resistant (MAR) bacteria (bacteria resistant to two or more antibiotics) and screened the MAR bacterial isolates obtained against five antibiotics by replica plating. Overall, 33.9% of 2,653 standard plate count bacteria from treated drinking waters were MAR. Two different raw water supplies for two communities carried MAR standard plate count bacteria at frequencies of 20.4 and 18.6%, whereas 36.7 and 67.8% of the standard plate count populations from sites within the respective distribution systems were MAR. Isolate identification revealed that MAR gram-positive cocci (Staphylococcus) and MAR gram-negative, nonfermentative rods (Pseudomonas, Alcaligenes, Moraxella-like group M, and Acinetobacter) were more common in drinking waters than in untreated source waters. Site-to-site variations in generic types and differences in the incidences of MAR organisms indicated that shedding of MAR bacteria living in pipelines may have contributed to the MAR populations in tap water. We conclude that the treatment of raw water and its subsequent distribution select for standard plate count bacteria exhibiting the MAR phenotype.

  5. Ribosomal Antibiotics: Contemporary Challenges

    Directory of Open Access Journals (Sweden)

    Tamar Auerbach-Nevo

    2016-06-01

    Full Text Available Most ribosomal antibiotics obstruct distinct ribosomal functions. In selected cases, in addition to paralyzing vital ribosomal tasks, some ribosomal antibiotics are involved in cellular regulation. Owing to the global rapid increase in the appearance of multi-drug resistance in pathogenic bacterial strains, and to the extremely slow progress in developing new antibiotics worldwide, it seems that, in addition to the traditional attempts at improving current antibiotics and the intensive screening for additional natural compounds, this field should undergo substantial conceptual revision. Here, we highlight several contemporary issues, including challenging the common preference of broad-range antibiotics; the marginal attention to alterations in the microbiome population resulting from antibiotics usage, and the insufficient awareness of ecological and environmental aspects of antibiotics usage. We also highlight recent advances in the identification of species-specific structural motifs that may be exploited for the design and the creation of novel, environmental friendly, degradable, antibiotic types, with a better distinction between pathogens and useful bacterial species in the microbiome. Thus, these studies are leading towards the design of “pathogen-specific antibiotics,” in contrast to the current preference of broad range antibiotics, partially because it requires significant efforts in speeding up the discovery of the unique species motifs as well as the clinical pathogen identification.

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

    Directory of Open Access Journals (Sweden)

    Jing Shao

    2012-09-01

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

  7. Erster Bericht über Klebsiella pneumoniae Carbapenemase-bildende Pseudomonas aeruginosa-Stämme, isoliert von Verbrennungspatienten im Iran: phenotypische und genotypische Methoden

    OpenAIRE

    Lari, AR; Azimi, L; Rahbar, M; Alaghehbandan, R; Sattarzadeh-Tabrizi, M

    2014-01-01

    Wound infection associated with carbapenem-resistant Pseudomonas aeruginosa in burn patients is a growing problem. One of the main mechanisms of resistance to carbapenem antibiotics is the ability of P. aeruginosa to produce carbapenemase enzymes. Klebsiella pneumonia carbapemenase (KPC) is an important type of carbapenemase which can hydrolyze carbapenem antibiotics. The Modified Hodge Test (MHT) and boronic acid as a KPC inhibitor are two phenotypic methods used for detection of carbapen...

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

    Directory of Open Access Journals (Sweden)

    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.    

  9. Targeting phenotypically tolerant Mycobacterium tuberculosis

    Science.gov (United States)

    Gold, Ben; Nathan, Carl

    2016-01-01

    While the immune system is credited with averting tuberculosis in billions of individuals exposed to Mycobacterium tuberculosis, the immune system is also culpable for tempering the ability of antibiotics to deliver swift and durable cure of disease. In individuals afflicted with tuberculosis, host immunity produces diverse microenvironmental niches that support suboptimal growth, or complete growth arrest, of M. tuberculosis. The physiological state of nonreplication in bacteria is associated with phenotypic drug tolerance. Many of these host microenvironments, when modeled in vitro by carbon starvation, complete nutrient starvation, stationary phase, acidic pH, reactive nitrogen intermediates, hypoxia, biofilms, and withholding streptomycin from the streptomycin-addicted strain SS18b, render M. tuberculosis profoundly tolerant to many of the antibiotics that are given to tuberculosis patients in a clinical setting. Targeting nonreplicating persisters is anticipated to reduce the duration of antibiotic treatment and rate of post-treatment relapse. Some promising drugs to treat tuberculosis, such as rifampicin and bedaquiline, only kill nonreplicating M. tuberculosis in vitro at concentrations far greater than their minimal inhibitory concentrations against replicating bacilli. There is an urgent demand to identify which of the currently used antibiotics, and which of the molecules in academic and corporate screening collections, have potent bactericidal action on nonreplicating M. tuberculosis. With this goal, we review methods of high throughput screening to target nonreplicating M. tuberculosis and methods to progress candidate molecules. A classification based on structures and putative targets of molecules that have been reported to kill nonreplicating M. tuberculosis revealed a rich diversity in pharmacophores. However, few of these compounds were tested under conditions that would exclude the impact of adsorbed compound acting during the recovery phase of

  10. Antibiotics and Breastfeeding.

    Science.gov (United States)

    de Sá Del Fiol, Fernando; Barberato-Filho, Silvio; de Cássia Bergamaschi, Cristiane; Lopes, Luciane Cruz; Gauthier, Timothy P

    2016-01-01

    During the breastfeeding period, bacterial infections can occur in the nursing mother, requiring the use of antibiotics. A lack of accurate information may lead health care professionals and mothers to suspend breastfeeding, which may be unnecessary. This article provides information on the main antibiotics that are appropriate for clinical use and the interference of these antibiotics with the infant to support medical decisions regarding the discontinuation of breastfeeding. We aim to provide information on the pharmacokinetic factors that interfere with the passage of antibiotics into breast milk and the toxicological implications of absorption by the infant. Publications related to the 20 most frequently employed antibiotics and their transfer into breast milk were evaluated. The results demonstrate that most antibiotics in clinical use are considered suitable during breastfeeding; however, the pharmacokinetic profile of each drug must be observed to ensure the resolution of the maternal infection and the safety of the infant. © 2016 S. Karger AG, Basel.

  11. High Antibiotic Consumption

    DEFF Research Database (Denmark)

    Malo, Sara; José Rabanaque, María; Feja, Cristina

    2014-01-01

    Heavy antibiotic users are those individuals with the highest exposure to antibiotics. They play an important role as contributors to the increasing risk of antimicrobial resistance. We applied different methods to identify and characterize the group of heavy antibiotic users in Spain as well...... as their exposure to antibiotics. Data on outpatient prescribing of antimicrobials (ATC J01) in 2010 were obtained from a prescription database covering Aragón (northeastern Spain). The antimicrobial consumption at the individual level was analysed both according to the volume of DDD and the number of packages...... purchased per year. Heavy antibiotic users were identified according to Lorenz curves and characterized by age, gender, and their antimicrobial prescription profile. Lorenz curves demonstrated substantial differences in the individual use of antimicrobials. Heavy antibiotic users (5% of individuals...

  12. Social interaction, noise and antibiotic-mediated switches in the intestinal microbiota.

    Directory of Open Access Journals (Sweden)

    Vanni Bucci

    Full Text Available The intestinal microbiota plays important roles in digestion and resistance against entero-pathogens. As with other ecosystems, its species composition is resilient against small disturbances but strong perturbations such as antibiotics can affect the consortium dramatically. Antibiotic cessation does not necessarily restore pre-treatment conditions and disturbed microbiota are often susceptible to pathogen invasion. Here we propose a mathematical model to explain how antibiotic-mediated switches in the microbiota composition can result from simple social interactions between antibiotic-tolerant and antibiotic-sensitive bacterial groups. We build a two-species (e.g. two functional-groups model and identify regions of domination by antibiotic-sensitive or antibiotic-tolerant bacteria, as well as a region of multistability where domination by either group is possible. Using a new framework that we derived from statistical physics, we calculate the duration of each microbiota composition state. This is shown to depend on the balance between random fluctuations in the bacterial densities and the strength of microbial interactions. The singular value decomposition of recent metagenomic data confirms our assumption of grouping microbes as antibiotic-tolerant or antibiotic-sensitive in response to a single antibiotic. Our methodology can be extended to multiple bacterial groups and thus it provides an ecological formalism to help interpret the present surge in microbiome data.

  13. Structure of polysaccharide antibiotics

    International Nuclear Information System (INIS)

    Matutano, L.

    1966-01-01

    Study of the structure of antibiotics having two or several sugars in their molecule. One may distinguish: the polysaccharide antibiotics themselves, made up of two or several sugars either with or without nitrogen, such as streptomycin, neomycins, paromomycine, kanamycin, chalcomycin; the hetero-polysaccharide antibiotics made up of one saccharide part linked to an aglycone of various type through a glucoside: macrolide, pigment, pyrimidine purine. Amongst these latter are: erythromycin, magnamycin, spiramycin, oleandomycin, cinerubin and amicetin. The sugars can either play a direct role in biochemical reactions or act as a dissolving agent, as far as the anti-microbe power of these antibiotics is concerned. (author) [fr

  14. Antibiotics: Miracle Drugs

    Centers for Disease Control (CDC) Podcasts

    2015-04-16

    The overuse of antibiotics has led to the development of resistance among bacteria, making antibiotics ineffective in treating certain conditions. This podcast discusses the importance of talking to your healthcare professional about whether or not antibiotics will be beneficial if you’ve been diagnosed with an infectious disease.  Created: 4/16/2015 by Division of Bacterial Diseases (DBD), National Center for Immunization and Respiratory Disease (NCIRD), Get Smart: Know When Antibiotics Work Program.   Date Released: 4/16/2015.

  15. Pseudomonas aeruginosa host-adaptation in cystic fibrosis patients

    DEFF Research Database (Denmark)

    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...

  16. The great escape: Pseudomonas breaks out of the lung

    Directory of Open Access Journals (Sweden)

    Angelica Zhang

    2015-09-01

    Full Text Available The Gram-negative bacterium Pseudomonas aeruginosa is a major cause of hospital-acquired infections and the focus of much attention due to its resistance to many conventional antibiotics. It harbors a wide range of disease-promoting virulence factors, including a type III secretion system. Here we review our recent study of ExoS, one of the effector proteins exported by this type III secretion system. Using a mouse model of pneumonia, we showed that the ADP-ribosyltransferase (ADPRT activity of ExoS caused formation of “fields of cell injection” (FOCI in the lungs. These FOCI represented ExoS-injected clusters of type I pneumocytes that became compromised, leading to disruption of the pulmonary-vascular barrier and subsequent bacterial dissemination from the lungs to the bloodstream. We discuss the potential mechanisms by which these processes occur as well as the novel techniques used to study ExoS function in vivo.

  17. 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.

  18. Genomic Evolution Of The Mdr Serotype O12 Pseudomonas Aeruginosa Clone

    DEFF Research Database (Denmark)

    Thrane, Sandra Wingaard; Taylor, Véronique L.; Freschi, Luca

    2015-01-01

    that serotype switching in combination with an antibiotic resistance determinant contributed to the dissemination of the O12 serotype in the clinic. This selective advantage coincides with the introduction of fluoroquinolones in the clinic. With the PAst program isolates can be serotyped using WGS data......Introduction: Since the 1980’s the serotype O12 of Pseudomonas aeruginosa has emerged as the predominant serotype in clinical settings and in epidemic outbreaks. These serotype O12 isolates exhibit high levels of resistance to various classes of antibiotics.Methods: In this study, we explore how......).Results: While most serotypes were closely linked to the core genome phylogeny we observed horizontal exchange of LPS genes among distinct P. aeruginosa strains. Specifically, we identified a ‘serotype island’ containing the P. aeruginosa O12 LPS gene cluster and an antibiotic resistance determinant (gyrAC248T...

  19. Spatiotemporal pharmacodynamics of meropenem- and tobramycin-treated Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Haagensen, Janus Anders Juul; Verotta, Davide; Huang, Liusheng

    2017-01-01

    The selection and dose of antibiotic therapy for biofilm-related infections are based on traditional pharmacokinetic studies using planktonic bacteria. The objective of this study was to characterize the time course and spatial activity of human exposure levels of meropenem and tobramycin against...... Pseudomonas aeruginosa biofilms grown in an in vitro flow-chamber model. Pharmacokinetic profiles of meropenem and tobramycin used in human therapy were administered to GFP-labelled P. aeruginosa PAO1 grown in flow chambers for 24 or 72 h. Images were acquired using confocal laser scanning microscopy...... throughout antibiotic treatment. Bacterial biomass was measured using COMSTAT and pharmacokinetic/pharmacodynamic models were fitted using NONMEM7. Meropenem treatment resulted in more rapid and sustained killing of both the 24 and 72 h PAO1 biofilm compared with tobramycin. Biofilm regrowth after antibiotic...

  20. 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

  1. Prevalence and analysis of Pseudomonas aeruginosa in chinchillas

    Directory of Open Access Journals (Sweden)

    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.

  2. Handling Time-dependent Variables : Antibiotics and Antibiotic Resistance

    NARCIS (Netherlands)

    Munoz-Price, L. Silvia; Frencken, Jos F.; Tarima, Sergey; Bonten, Marc

    2016-01-01

    Elucidating quantitative associations between antibiotic exposure and antibiotic resistance development is important. In the absence of randomized trials, observational studies are the next best alternative to derive such estimates. Yet, as antibiotics are prescribed for varying time periods,

  3. Boolean network model of the Pseudomonas aeruginosa quorum sensing circuits.

    Science.gov (United States)

    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.

  4. [Antibiotic therapy of hospital-acquired pneumonia and its pharmacoeconomics].

    Science.gov (United States)

    Kolář, Milan; Htoutou Sedláková, Miroslava; Urbánek, Karel; Uvízl, Radomír; Adamus, Milan; Imwensi, O P

    2016-03-01

    Important hospital-acquired infections include pneumonia, mainly because of the increasing resistance of bacterial pathogens to antimicrobials and the associated potential failure of antibiotic therapy. The present study aimed at determining the most frequent etiological agents of hospital-acquired pneumonia (HAP) and assessing the relationship between 30-day mortality and adequacy of antibiotic therapy. Based on the obtained information, optimal patterns of antibiotic therapy were to be defined, including a pharmacoeconomic perspective. In patients with clinically confirmed HAP, bacterial etiological agents were identified, their susceptibility to antimicrobials was determined and statistical methods were used to assess the relationship between adequacy of antibiotic therapy and 30-day mortality. The study comprised 68 patients with clinically confirmed HAP. The most common etiological agents were strains of Pseudomonas aeruginosa (30.8 %), Klebsiella pneumoniae (23.1 %) and Burkholderia cepacia complex (15.4 %). Gram-negative bacteria accounted for 86.5 % of all bacterial pathogens. The overall mortality reached 42.5 %. In the subgroup of patients with inadequate antibiotic therapy, 30-day mortality was significantly higher (83.3 %) than in the subgroup with adequate therapy (30.0 %; p = 0.002). The risk for 30-day mortality was 2.78 times higher in case of inadequate antibiotic therapy (95%CI: 1.52-5.07). The proportion of Pseudomonas aeruginosa strains was significantly higher in the subgroup of patients with inadequate antibiotic therapy than in those with adequate therapy (67 % vs. 27 %; p = 0.032). Results of the present study suggest a significant relationship between mortality of patients with HAP and ineffective antibiotic therapy due to resistance of the bacterial pathogen. Thus, it is clear that initial antibiotic therapy must be based on qualified assumption of sufficient activity against the most common bacterial pathogens and results of surveillance

  5. Draft Genome Sequence of Pseudomonas sp. EpS/L25, Isolated from the Medicinal Plant Echinacea purpurea and Able To Synthesize Antimicrobial Compounds.

    Science.gov (United States)

    Presta, Luana; Bosi, Emanuele; Fondi, Marco; Maida, Isabel; Perrin, Elena; Miceli, Elisangela; Maggini, Valentina; Bogani, Patrizia; Firenzuoli, Fabio; Di Pilato, Vincenzo; Rossolini, Gian Maria; Mengoni, Alessio; Fani, Renato

    2016-05-05

    We announce here the draft genome sequence of Pseudomonas sp. strain EpS/L25, isolated from the stem/leaves of the medicinal plant Echinacea purpurea This genome will allow for comparative genomics in order to identify genes associated with the production of bioactive compounds and antibiotic resistance. Copyright © 2016 Presta et al.

  6. Exploring Marine Environments To Unravel Tolerance Mechanisms To Relevant Compounds

    DEFF Research Database (Denmark)

    Machado, Henrique; Cavaleiro, Mafalda; Nørholm, Morten

    2015-01-01

    Production of biofuels and chemicals using microorganisms has been a research driver in the last decades. The approach started with the engineering of metabolic pathways for production of compounds of interest, but it was soon realized that tolerance to the compounds being produced was one...... of interest, HPLC analyses were performed in order to distinguish between compound-degrading and tolerant bacteria. This led to the identification of seven tolerant and non-degrading isolates, the most interesting ones belonging to the genera Bacillus and Pseudomonas. These will be studied using genomic...... and transcriptomic approaches to identify the tolerance mechanisms used. Exploring new ecological niches, as contaminated marine environments allows the identification of naturally tolerant bacteria to the compounds of interest and most likely to the discovery of new mechanisms of tolerance....

  7. [Antibiotics: present and future].

    Science.gov (United States)

    Bérdy, János

    2013-04-14

    The author discuss the up to date interpretation of the concept of antibiotics and antibiotic research, as well as the present role of various natural, semisynthetic and synthetic antibiotic compounds in various areas of the human therapy. The origin and the total number of all antibiotics and applied antibiotics in the practice, as well as the bioactive microbial metabolites (antibiotics) in other therapeutical, non-antibiotic fields (including agriculture) are also reviewed. The author discusses main problems, such as increasing (poly)resistance, virulence of pathogens and the non-scientific factors (such as a decline of research efforts and their sociological, economic, financial and regulatory reasons). A short summary of the history of Hungarian antibiotic research is also provided. The author briefly discusses the prospects in the future and the general advantages of the natural products over synthetic compounds. It is concluded that new approaches for the investigation of the unlimited possibilities of the living world are necessary. The discovery of new types or simply neglected (micro)organisms and their biosynthetic capabilities, the introduction of new biotechnological and genetic methods (genomics, metagenom, genome mining) are absolutely required in the future.

  8. The future of antibiotics

    Science.gov (United States)

    2014-01-01

    Antibiotic resistance continues to spread even as society is experiencing a market failure of new antibiotic research and development (R&D). Scientific, economic, and regulatory barriers all contribute to the antibiotic market failure. Scientific solutions to rekindle R&D include finding new screening strategies to identify novel antibiotic scaffolds and transforming the way we think about treating infections, such that the goal is to disarm the pathogen without killing it or modulate the host response to the organism without targeting the organism for destruction. Future economic strategies are likely to focus on ‘push’ incentives offered by public-private partnerships as well as increasing pricing by focusing development on areas of high unmet need. Such strategies can also help protect new antibiotics from overuse after marketing. Regulatory reform is needed to re-establish feasible and meaningful traditional antibiotic pathways, to create novel limited-use pathways that focus on highly resistant infections, and to harmonize regulatory standards across nations. We need new antibiotics with which to treat our patients. But we also need to protect those new antibiotics from misuse when they become available. If we want to break the cycle of resistance and change the current landscape, disruptive approaches that challenge long-standing dogma will be needed. PMID:25043962

  9. Towards Tolerance

    NARCIS (Netherlands)

    Lisette Kuyper; Jurjen Iedema; Saskia Keuzenkamp

    2013-01-01

    Across Europe, public attitudes towards lesbian, gay and bisexual (LGB) individuals range from broad tolerance to widespread rejection. Attitudes towards homosexuality are more than mere individual opinions, but form part of the social and political structures which foster or hinder the equality

  10. Intolerant tolerance.

    Science.gov (United States)

    Khushf, G

    1994-04-01

    The Hyde Amendment and Roman Catholic attempts to put restrictions on Title X funding have been criticized for being intolerant. However, such criticism fails to appreciate that there are two competing notions of tolerance, one focusing on the limits of state force and accepting pluralism as unavoidable, and the other focusing on the limits of knowledge and advancing pluralism as a good. These two types of tolerance, illustrated in the writings of John Locke and J.S. Mill, each involve an intolerance. In a pluralistic context where the free exercise of religion is respected, John Locke's account of tolerance is preferable. However, it (in a reconstructed form) leads to a minimal state. Positive entitlements to benefits like artificial contraception or nontherapeutic abortions can legitimately be resisted, because an intolerance has already been shown with respect to those that consider the benefit immoral, since their resources have been coopted by taxation to advance an end that is contrary to their own. There is a sliding scale from tolerance (viewed as forbearance) to the affirmation of communal integrity, and this scale maps on to the continuum from negative to positive rights.

  11. Current therapies for pseudomonas aeruginosa.

    Science.gov (United States)

    Giamarellou, Helen; Kanellakopoulou, Kyriaki

    2008-04-01

    Based on the worldwide prevalence of multidrug-resistant strains of Pseudomas aeruginosa and the fact that no newer antipseudomonal agents are available, this article aims to investigate therapeutic solutions for combating infections caused by P aeruginosa, including multidrug-resistant strains. The article focuses mainly on colistin, the re-emerging old antibiotic that possesses prominent antipseudomonal activity in vitro and on doripenem, a newer carbapenem that seems to be close to its global marketing. Regarding older antipseudomonal antibiotics that have been reviewed extensively, only newer aspects on their use are considered in this article.

  12. Opportunistic microorganisms in patients undergoing antibiotic therapy for pulmonary tuberculosis

    Directory of Open Access Journals (Sweden)

    Silvia Maria Rodrigues Querido

    2011-12-01

    Full Text Available Antimicrobial therapy may cause changes in the resident oral microbiota, with the increase of opportunistic pathogens. The aim of this study was to compare the prevalence of Candida, Staphylococcus, Pseudomonas and Enterobacteriaceae in the oral cavity of fifty patients undergoing antibiotic therapy for pulmonary tuberculosis and systemically healthy controls. Oral rinsing and subgingival samples were obtained, plated in Sabouraud dextrose agar with chloramphenicol, mannitol agar and MacConkey agar, and incubated for 48 h at 37ºC. Candida spp. and coagulase-positive staphylococci were identified by phenotypic tests, C. dubliniensis, by multiplex PCR, and coagulase-negative staphylococci, Enterobacteriaceae and Pseudomonas spp., by the API systems. The number of Candida spp. was significantly higher in tuberculosis patients, and C. albicans was the most prevalent specie. No significant differences in the prevalence of other microorganisms were observed. In conclusion, the antimicrobial therapy for pulmonary tuberculosis induced significant increase only in the amounts of Candida spp.

  13. History of Antibiotics Research.

    Science.gov (United States)

    Mohr, Kathrin I

    2016-01-01

    For thousands of years people were delivered helplessly to various kinds of infections, which often reached epidemic proportions and have cost the lives of millions of people. This is precisely the age since mankind has been thinking of infectious diseases and the question of their causes. However, due to a lack of knowledge, the search for strategies to fight, heal, and prevent the spread of communicable diseases was unsuccessful for a long time. It was not until the discovery of the healing effects of (antibiotic producing) molds, the first microscopic observations of microorganisms in the seventeenth century, the refutation of the abiogenesis theory, and the dissolution of the question "What is the nature of infectious diseases?" that the first milestones within the history of antibiotics research were set. Then new discoveries accelerated rapidly: Bacteria could be isolated and cultured and were identified as possible agents of diseases as well as producers of bioactive metabolites. At the same time the first synthetic antibiotics were developed and shortly thereafter, thousands of synthetic substances as well as millions of soil borne bacteria and fungi were screened for bioactivity within numerous microbial laboratories of pharmaceutical companies. New antibiotic classes with different targets were discovered as on assembly line production. With the beginning of the twentieth century, many of the diseases which reached epidemic proportions at the time-e.g., cholera, syphilis, plague, tuberculosis, or typhoid fever, just to name a few, could be combatted with new discovered antibiotics. It should be considered that hundred years ago the market launch of new antibiotics was significantly faster and less complicated than today (where it takes 10-12 years in average between the discovery of a new antibiotic until the launch). After the first euphoria it was quickly realized that bacteria are able to develop, acquire, and spread numerous resistance mechanisms

  14. Biosurfactants in plant-Pseudomonas interactions and their importance to biocontrol.

    Science.gov (United States)

    D'aes, Jolien; De Maeyer, Katrien; Pauwelyn, Ellen; Höfte, Monica

    2010-06-01

    Production of biosurfactants is a common feature in bacteria, and in particular in plant-associated species. These bacteria include many plant beneficial and plant pathogenic Pseudomonas spp., which produce primarily cyclic lipopeptide and rhamnolipid type biosurfactants. Pseudomonas-derived biosurfactants are involved in many important bacterial functions. By modifying surface properties, biosurfactants can influence common traits such as surface motility, biofilm formation and colonization. Biosurfactants can alter the bio-availability of exogenous compounds, such as nutrients, to promote their uptake, and of endogenous metabolites, including phenazine antibiotics, resulting in an enhanced biological activity. Antibiotic activity of biosurfactants towards microbes could play a role in intraspecific competition, self-defence and pathogenesis. In addition, bacterial surfactants can affect plants in different ways, either protecting them from disease, or acting as a toxin in a plant-pathogen interaction. Biosurfactants are involved in the biocontrol activity of an increasing number of Pseudomonas strains. Consequently, further insight into the roles and activities of surfactants produced by bacteria could provide means to optimize the use of biological control as an alternative crop protection strategy. © 2009 Society for Applied Microbiology and Blackwell Publishing Ltd.

  15. 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)

  16. A Putative ABC Transporter Permease Is Necessary for Resistance to Acidified Nitrite and EDTA in Pseudomonas aeruginosa under Aerobic and Anaerobic Planktonic and Biofilm Conditions.

    Science.gov (United States)

    McDaniel, Cameron; Su, Shengchang; Panmanee, Warunya; Lau, Gee W; Browne, Tristan; Cox, Kevin; Paul, Andrew T; Ko, Seung-Hyun B; Mortensen, Joel E; Lam, Joseph S; Muruve, Daniel A; Hassett, Daniel J

    2016-01-01

    Pseudomonas aeruginosa (PA) is an important airway pathogen of cystic fibrosis and chronic obstructive disease patients. Multiply drug resistant PA is becoming increasing prevalent and new strategies are needed to combat such insidious organisms. We have previously shown that a mucoid, mucA22 mutant PA is exquisitely sensitive to acidified nitrite ([Formula: see text], pH 6.5) at concentrations that are well tolerated in humans. Here, we used a transposon mutagenesis approach to identify PA mutants that are hypersensitive to [Formula: see text]. Among greater than 10,000 mutants screened, we focused on PA4455, in which the transposon was found to disrupt the production of a putative cytoplasmic membrane-spanning ABC transporter permease. The PA4455 mutant was not only highly sensitive to [Formula: see text], but also the membrane perturbing agent, EDTA and the antibiotics doxycycline, tigecycline, colistin, and chloramphenicol, respectively. Treatment of bacteria with [Formula: see text] plus EDTA, however, had the most dramatic and synergistic effect, with virtually all bacteria killed by 10 mM [Formula: see text], and EDTA (1 mM, aerobic, anaerobic). Most importantly, the PA4455 mutant was also sensitive to [Formula: see text] in biofilms. [Formula: see text] sensitivity and an anaerobic growth defect was also noted in two mutants (rmlC and wbpM) that are defective in B-band LPS synthesis, potentially indicating a membrane defect in the PA4455 mutant. Finally, this study describes a gene, PA4455, that when mutated, allows for dramatic sensitivity to the potential therapeutic agent, [Formula: see text] as well as EDTA. Furthermore, the synergy between the two compounds could offer future benefits against antibiotic resistant PA strains.

  17. Pseudomonas-follikulitis efter badning i spabad

    DEFF Research Database (Denmark)

    Uldall Pallesen, Kristine Appel; Andersen, Klaus Ejner; Mørtz, Charlotte Gotthard

    2012-01-01

    . We describe a 23-year-old healthy woman who developed a pustular rash and general malaise after using a spa bath contaminated with Pseudomonas aeruginosa. Bacterial culture from a pustule confirmed Pseudomonas folliculitis and the patient was treated with ciprofloxacin with rapid good effect....

  18. Pseudomonas Septic Arthritis | Thanni | Nigerian Journal of ...

    African Journals Online (AJOL)

    BACKGROUND: Septic arthritis due to pseudomonas species is unusual and when it occurs, there is often an underlying cause like immune depression, intravenous drug abuse or a penetrating injury. PATIENT AND METHOD: We report a case of pseudomonas septic arthritis complicating cannulation of a leg vein following ...

  19. Pseudomonas-related populations associated with reverse osmosis in drinking water treatment.

    Science.gov (United States)

    Sala-Comorera, Laura; Blanch, Anicet R; Vilaró, Carles; Galofré, Belén; García-Aljaro, Cristina

    2016-11-01

    Reverse osmosis membrane filtration technology (RO) is used to treat drinking water. After RO treatment, bacterial growth is still observed in water. However, it is not clear whether those microorganisms belong to species that can pose a health risk, such as Pseudomonas spp. The goal of this study is to characterize the bacterial isolates from a medium that is selective for Pseudomonas and Aeromonas which were present in the water fraction before and after the RO. To this end, isolates were recovered over two years and were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. They were then biochemically phenotyped and the population similarity indexes were calculated. The isolates were analysed for their capacity to form biofilms in vitro and antimicrobial susceptibility. There were significant differences between the microbial populations in water before and after RO. Furthermore, the structures of the populations analysed at the same sampling point were similar in different sampling campaigns. Some of the isolates had the capacity to form a biofilm and showed resistance to different antibiotics. A successful level filtration via RO and subsequent recolonization of the membrane with different species from those in the feed water was found. Pseudomonas aeruginosa was not recovered from among the isolates. This study increases the knowledge on the microorganisms present in water after RO treatment, with focus in one of the genus causing problems in RO systems associated with human health risk, Pseudomonas. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Mutant Prevention Concentrations of Imipenem and Meropenem against Pseudomonas aeruginosa and Acinetobacter baumannii

    Directory of Open Access Journals (Sweden)

    E. Dahdouh

    2014-01-01

    Full Text Available The aim of this study was to determine the usefulness of the MPC of carbapenems against clinical isolates of Pseudomonas spp. and Acinetobacter spp. and to assess its possible relationship with mechanisms of resistance. Detection of the mechanisms of resistance was performed using Antibiotic Susceptibility Testing, Double Disk Synergy, disk antagonism, addition of NaCl to the medium, addition of PBA or EDTA to Carbapenem disks, addition of PBA to Cefoxitin disks, and CCCP test for 10 Pseudomonas spp. and Acinetobacter baumannii strains. The MIC and MPC were determined using the broth macrodilution and plate dilution methods, respectively. Four Acinetobacter baumannii strains produced MBL. Two of them produced Oxacillinase and one produced ESBL. Two Pseudomonas spp. isolates produced both KPC and MBL. The resistant Acinetobacter spp. and Pseudomonas spp. strains had higher MPC values than susceptible ones. However, the Mutant Selection Window was found to be dependent on the degree of resistance but not on a particular mechanism of resistance. The usefulness of the MPC was found to be dependent on its value. Based on our data, we recommend determining the MPC for each isolate before using it during treatment. Furthermore, the use of T>MSW instead of T>MIC is suggested.

  1. Antifungal activity and genetic diversity of selected Pseudomonas spp. from maize rhizosphere in Vojvodina

    Directory of Open Access Journals (Sweden)

    Jošić Dragana

    2012-01-01

    Full Text Available Antibiotic production by plant-associated microorganisms represents an environmentally compatible method of disease control in agriculture. However, a vide application of bacterial strains needs careful selection and genetic characterization. In this investigation, selected Pseudomonas strains were characterized by rep-PCR methods using ERIC and (GTG5 primers, and partial 16S rDNA sequence analysis. None of strains produced homoserine lactones (C4, C6, C8 as quorum sensing signal molecules. Very poor production of phenazines and no significant fungal inhibition was observed for PS4 and PS6 strains. High amount of phenazines were produced by Pseudomonas sp. strain PS2, which inhibited mycelial growth of 10 phytopatogenic fungi in percent of 25 (Verticillium sp. to 65 (Fusarium equiseti. Genetic characterization of the Pseudomonas sp. PS2 and evaluation of phenazines production, as the main trait for growth inhibition of phytopathogenic fungi, will allow its application as a biosafe PGPR for field experiments of plant disease control. [Projekat Ministarstva nauke Republike Srbije, br. III 46007: New indigenous bacterial isolates Lysobacter and Pseudomonas as an important sources of metabolites useful for biotechnology, plant growth stimulation and disease control: From isolates to inoculants

  2. Efflux pump-deficient mutants as a platform to search for microbes that produce antibiotics.

    Science.gov (United States)

    Molina-Santiago, Carlos; Udaondo, Zulema; Daddaoua, Abdelali; Roca, Amalia; Martín, Jesús; Pérez-Victoria, Ignacio; Reyes, Fernando; Ramos, Juan-Luis

    2015-07-01

    Pseudomonas putida DOT-T1E-18 is a strain deficient in the major antibiotic efflux pump (TtgABC) that exhibits an overall increased susceptibility to a wide range of drugs when compared with the wild-type strain. We used this strain as a platform to search for microbes able to produce antibiotics that inhibit growth. A collection of 2400 isolates from soil, sediments and water was generated and a drop assay developed to identify, via growth inhibition halos, strains that prevent the growth of DOT-T1E-18 on solid Luria-Bertani plates. In this study, 35 different isolates that produced known and unknown antibiotics were identified. The most potent inhibitor of DOT-T1E-18 growth was an isolate named 250J that, through multi-locus sequence analysis, was identified as a Pseudomonas sp. strain. Culture supernatants of 250J contain four different xantholysins that prevent growth of Gram-positive bacteria, Gram-negative and fungi. Two of the xantholysins were produced in higher concentrations and purified. Xantholysin A was effective against Bacillus, Lysinibacillus and Rhodococcus strains, and the effect against these microbes was enhanced when used in combination with other antibiotics such as ampicillin, gentamicin and kanamycin. Xantholysin C was also efficient against Gram-positive bacteria and showed an interesting antimicrobial effect against Pseudomonas strains, and a synergistic inhibitory effect with ampicillin, chloramphenicol and gentamicin. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  3. Induction of bacterial antibiotic resistance by mutagenic halogenated nitrogenous disinfection byproducts

    International Nuclear Information System (INIS)

    Lv, Lu; Yu, Xin; Xu, Qian; Ye, Chengsong

    2015-01-01

    Halogenated nitrogenous disinfection byproducts (N-DBPs) raise concerns regarding their mutagenicity and carcinogenicity threatening public health. However, environmental consequence of their mutagenicity has received less attention. In this study, the effect of halogenated N-DBPs on bacterial antibiotic resistance (BAR) was investigated. After exposure to bromoacetamide (BAcAm), trichloroacetonitrile (TCAN) or tribromonitromethane (TBNM), the resistance of Pseudomonas aeruginosa PAO1 to both individual and multiple antibiotics (ciprofloxacin, gentamicin, polymyxin B, rifampin, tetracycline, ciprofloxacin + gentamicin and ciprofloxacin + tetracycline) was increased, which was predominantly ascribed to the overexpression of efflux pumps. The mechanism of this effect was demonstrated to be mutagenesis through sequencing and analyzing antibiotic resistance genes. The same induction phenomena also appeared in Escherichia coli, suggesting this effect may be universal to waterborne pathogens. Therefore, more attention should be given to halogenated N-DBPs, as they could increase not only genotoxicological risks but also epidemiological risks of drinking water. - Highlights: • The halogenated N-DBPs could induce bacterial antibiotic resistance. • Both individual and multiple resistances could be induced. • Efflux mechanism played an important role in the induced antibiotic resistance. • The halogenated N-DBPs induced bacterial antibiotic resistance via mutagenesis. • Effects of N-DBPs on antibiotic resistance may be universal to waterborne pathogens. - Halogenated N-DBPs could increase antibiotic resistance, even multidrug resistance via mutagenesis, contributing to the enrichment of antibiotic resistant bacteria in drinking water

  4. Effect of antibiotics on Agave fourcroydes Lem in vitro propagation

    Directory of Open Access Journals (Sweden)

    Enildo Abreu

    2016-01-01

    Full Text Available High microbial contamination on henequen (Agave fourcroydes Lem in vitro propagation reduces its efficiency. This work aimed to determine the effect of the use of antibiotics in the control of bacterial contaminants of this culture. Bacterial contaminants were identified and their susceptibility to different antibiotics it were determined. The two best-acting antibiotics were added to the propagation medium and the number of explants contaminated with bacteria and necrotics was quantified. The antibiotic and concentration that did not cause phytotoxicity to the explants and where the lowest percentage of contamination was obtained it was used to continue the propagation of the plants. These were transferred to the acclimatization stage and at 30 days of culture the number of live plants and the number of roots per plant were quantified. In addition, the length of the roots (cm was measured and the leaf area was calculated. Micrococcus spp., Pseudomonas spp., Agrobacterium spp., Bacillus subtilis and Bacillus licheniformis were found. The antibiotics tested inhibited the in vitro growth of the isolated contaminants and the best results were obtained with Ticar and Cefotaxime. Added to the plant propagation medium, Ticar was phytotoxic over 50 mg l-1 and cefotaxime could be used at 100 mg l-1 without causing damage to the explants. The results showed that the plants that came from the culture medium with cefotaxime 100 mg l-1 showed a significant increase of the variables evaluated in the acclimatization stage.   Key words: betalactamic, henequen, micropropagation

  5. Antibiotic Therapy in Pyogenic Meningitis in Paediatric Patients

    International Nuclear Information System (INIS)

    Tajdin, F.; Rasheed, M.A.; Ashraf, M.; Khan, G.J.; Rasheed, H.; Ejaz, H.

    2013-01-01

    Objective: To isolate and identify the causative pathogen, antibiotic sensitivity testing and success rate of empirical antibiotic therapy in pyogenic meningitis. Study Design: Analytical study. Place and Duration of Study: The Children's Hospital and Institute of Child Health, Lahore, Pakistan, from March to July 2012. Methodology: The study was performed on 72 culture positive meningitis cases in children less than 15 years of age. This therapy was evaluated by monitoring the patient's clinical picture for 14 - 21 days. The collected data was analyzed by Chi-square test. Results: Seventeen different bacteria were isolated. The most commonly occurring bacteria were coagulase negative Staphylococci (25%), E. coli (12.5%), Klebsiella pneumoniae (8.3%), Streptococcus pneumoniae (8.3%) and Pseudomonas aeruginosa (8.3%). All the bacteria were sensitive to vancomycin (96.7%), meropenem (76.7%), amikacin (75%), ciprofloxacin (65.3%), chloramphenicol (46.5%), ceftazidime (44.2%), cefepime (41.9%), co-amoxiclav (38.0%), oxacillin (34.8%), cefotaxime (21.4%), penicillin (20.7%), ceftriaxone (18.6%), cefuroxime (14%) and ampicillin (6.9%). The combination of sulbactam and cefoperazone showed antimicrobial sensitivity of 81.4%. The success rate of empirical antibiotic therapy was 91.7%. Conclusion: It was found that Gram negative bacteria were the major cause of pyogenic meningitis. Mostly there were resistant strains against all commonly used antibiotics except vancomycin. All empirical antibiotic therapies were found to be most successful. (author)

  6. Pathogenic factors of Pseudomonas aeruginosa – the role of biofilm in pathogenicity and as a target for phage therapy

    Directory of Open Access Journals (Sweden)

    Fairoz Al-Wrafy

    2017-02-01

    Full Text Available Pseudomonas aeruginosa is an opportunistic pathogen that can cause several acute and chronic infections in humans, and it has become an important cause of nosocomial infections and antibiotic resistance. Biofilm represents an important virulence factor for these bacteria, plays a role in P. aeruginosa infections and avoidance of immune defence mechanisms, and has the ability to protect the bacteria from antibiotics. Alginate, Psl and Pel, three exopolysaccharides, are the main components in biofilm matrix, with many biological functions attributed to them, especially with respect to the protection of the bacterial cell from antibiotics and the immune system. Pseudomonas infections, biofilm formation and development of resistance to antibiotics all require better understanding to achieve the best results using alternative treatment with phage therapy. This review describes the P. aeruginosa pathogenicity and virulence factors with a special focus on the biofilm and its role in infection and resistance to antibiotics and summarizes phage therapy as an alternative approach in treatment of P. aeruginosa infections.

  7. Salt Tolerance

    OpenAIRE

    Xiong, Liming; Zhu, Jian-Kang

    2002-01-01

    Studying salt stress is an important means to the understanding of plant ion homeostasis and osmo-balance. Salt stress research also benefits agriculture because soil salinity significantly limits plant productivity on agricultural lands. Decades of physiological and molecular studies have generated a large body of literature regarding potential salt tolerance determinants. Recent advances in applying molecular genetic analysis and genomics tools in the model plant Arabidopsis thaliana are sh...

  8. [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.

  9. Isolation and Molecular Characterization of a Model Antagonistic Pseudomonas aeruginosa Divulging In Vitro Plant Growth Promoting Characteristics

    Directory of Open Access Journals (Sweden)

    Bushra Uzair

    2018-01-01

    Full Text Available The use of microbial technologies in agriculture is currently expanding quite rapidly with the identification of new bacterial strains, which are more effective in promoting plant growth. In the present study 18 strains of Pseudomonas were isolated from soil sample of Balochistan coastline. Among isolated Pseudomonas strains four designated as SP19, SP22, PS24, and SP25 exhibited biocontrol activities against phytopathogenic fungi, that is, Rhizopus microsporus, Fusarium oxysporum, Aspergillus niger, Alternaria alternata, and Penicillium digitatum; PS24 identified as Pseudomonas aeruginosa by 16srRNA gene bank accession number EU081518 was selected on the basis of its antifungal activity to explore its potential as plant growth promotion. PS24 showed multiple plant growth promoting attributes such as phosphate solubilization activity, indole acetic acid (IAA, siderophore, and HCN production. In order to determine the basis for antifungal properties, antibiotics were extracted from King B broth of PS24 and analyzed by TLC. Pyrrolnitrin antibiotic was detected in the culture of strain PS24. PS24 exhibited antifungal activities found to be positive for hydrogen cyanide synthase Hcn BC gene. Sequencing of gene of Hcn BC gene of strain PS24 revealed 99% homology with the Pseudomonas aeruginosa strain PA01. The sequence of PS24 had been submitted in gene bank accession number KR605499. Ps. aeruginosa PS24 with its multifunctional biocontrol possessions can be used to bioprotect the crop plants from phytopathogens.

  10. The phenotypic evolution of Pseudomonas aeruginosa populations changes in the presence of subinhibitory concentrations of ciprofloxacin

    DEFF Research Database (Denmark)

    Wassermann, Tina; Meinike Jørgensen, Karin; Ivanyshyn, Karolina

    2016-01-01

    Ciprofloxacin is a widely used antibiotic, in the class of quinolones, for treatment of Pseudomonas aeruginosa infections. The immediate response of P. aeruginosa to subinhibitory concentrations of ciprofloxacin has been investigated previously. However, the long-term phenotypic adaptation, which...... populations compared to unexposed populations. Three replicate populations of P. aeruginosa PAO1 and its hypermutable mutant ΔmutS were cultured aerobically for approximately 940 generations by daily passages in LB medium with and without subinhibitory concentration of ciprofloxacin and aliquots...

  11. Addressing resistance to antibiotics in systematic reviews of antibiotic interventions

    NARCIS (Netherlands)

    Leibovici, Leonard; Paul, Mical; Garner, Paul; Sinclair, David J; Afshari, Arash; Pace, Nathan Leon; Cullum, Nicky; Williams, Hywel C; Smyth, Alan; Skoetz, Nicole; Del Mar, Chris; Schilder, Anne G M; Yahav, Dafna; Tovey, David

    Antibiotics are among the most important interventions in healthcare. Resistance of bacteria to antibiotics threatens the effectiveness of treatment. Systematic reviews of antibiotic treatments often do not address resistance to antibiotics even when data are available in the original studies. This

  12. Quantitative approach to track lipase producing Pseudomonas sp. S1 in nonsterilized solid state fermentation.

    Science.gov (United States)

    Sahoo, R K; Subudhi, E; Kumar, M

    2014-06-01

    Proliferation of the inoculated Pseudomonas sp. S1 is quantitatively evaluated using ERIC-PCR during the production of lipase in nonsterile solid state fermentation an approach to reduce the cost of enzyme production. Under nonsterile solid state fermentation with olive oil cake, Pseudomonas sp. S1 produced 57·9 IU g(-1) of lipase. DNA fingerprints of unknown bacterial isolates obtained on Bushnell Haas agar (BHA) + tributyrin exactly matched with that of Pseudomonas sp. S1. Using PCR-based enumeration, population of Pseudomonas sp. S1 was proliferated from 7·6 × 10(4) CFU g(-1) after 24 h to 4·6 × 10(8) CFU g(-1) after 96 h, which tallied with the maximum lipase activity as compared to control. Under submerged fermentation (SmF), Pseudomonas sp. S1 produced maximum lipase (49 IU ml(-1) ) using olive oil as substrate, while lipase production was 9·754 IU ml(-1) when Pseudomonas sp. S1 was grown on tributyrin. Optimum pH and temperature of the crude lipase was 7·0 and 50°C. Crude enzyme activity was 71·2% stable at 50°C for 360 min. Pseudomonas sp. S1 lipase was also stable in methanol showing 91·6% activity in the presence of 15% methanol, whereas 75·5 and 51·1% of activity were retained in the presence of 20 and 30% methanol, respectively. Thus, lipase produced by Pseudomonas sp. S1 is suitable for the production of biodiesel as well as treatment of oily waste water. This study presents the first report on the production of thermophilic organic solvent tolerant lipase using agro-industry waste in nonsterile solid state fermentation. Positive correlation between survival of Pseudomonas sp. S1 and lipase production under nonsterile solid state fermentation was established, which may emphasize the need to combine molecular tools and solid state fermentation in future studies. Our study brings new insights into the lipase production in cost-effective manner, which is an industrially relevant approach. © 2014 The Society for Applied Microbiology.

  13. [Antibiotic treatment for prevention of infectious complications in joint replacement].

    Science.gov (United States)

    Jahoda, D; Nyc, O; Pokorný, D; Landor, I; Sosna, A

    2006-04-01

    used only in indicated cases when deep infection is suspected and no assessment of the causative agent is available. Otherwise this approach carries a high risk of infectious complications in aseptic revision arthroplasty. Long-term, unjustified administration of antibiotics leads to an increase in resistance to the antibiotic involved. Some studies show that a day's course is as effective as a seven-day one. A shorter antibiotic course decreases the costs, reduces side-effects and minimizes the development of resistance. An optimal duration of antibiotic treatment has not been defined yet, and is still a hot issue for discussion. Many authors recommend one pre-operative antibiotic dose and, according to the kind of antibiotic, agree to its 24-hour administration in order to lower the toxic effect of antibiotic and to prevent selection of resistant microorganisms. The choice of suitable antibiotics for prophylactic treatment should be based on the range of agents causing joint replacement infections and the pharmacological properties of the drug. This should have minimal toxicity, should be well tolerated by the patient and, from the epidemiological point of view, should have a low risk of inducing resistance because of frequent use. Naturally, it is not possible to include all antibiotics against all causative agents and therefore attention should be paid, in the first place, to Gram-positive bacteria, i. e., staphylococci and streptococci, which are the most common causes of infectious complications associated with joint replacement. Because of difficulties related to the right choice of antibiotic, it is recommended to keep a record of complications in each patient in order to provide feedback and to facilitate the establishment of reliable antibiotic-based prevention. The prevention of infection in orthopedics is a comprehensive issue. It cannot be expected that prophylactic antibiotic treatment will compensate for mistakes made in operative protocols, for

  14. Fighting antibiotic resistance in the intensive care unit using antibiotics.

    Science.gov (United States)

    Plantinga, Nienke L; Wittekamp, Bastiaan H J; van Duijn, Pleun J; Bonten, Marc J M

    2015-01-01

    Antibiotic resistance is a global and increasing problem that is not counterbalanced by the development of new therapeutic agents. The prevalence of antibiotic resistance is especially high in intensive care units with frequently reported outbreaks of multidrug-resistant organisms. In addition to classical infection prevention protocols and surveillance programs, counterintuitive interventions, such as selective decontamination with antibiotics and antibiotic rotation have been applied and investigated to control the emergence of antibiotic resistance. This review provides an overview of selective oropharyngeal and digestive tract decontamination, decolonization of methicillin-resistant Staphylococcus aureus and antibiotic rotation as strategies to modulate antibiotic resistance in the intensive care unit.

  15. Diabetic foot gangrene patient with multi-drug resistant Pseudomonas putida infection in Karawaci District, Indonesia

    Directory of Open Access Journals (Sweden)

    Nata Pratama Hardjo Lugito

    2015-01-01

    Full Text Available Pseudomonas putida is a rod-shaped, non fermenting Gram-negative organism frequently found in the environment that utilizes aerobic metabolism, previously thought to be of low pathogenicity. It had been reported as cause of skin and soft tissue infection, especially in immunocompromised patients. A female green grocer, 51 year-old came to internal medicine out-patient clinic with gangrene and osteomyelitis on her 1 st , 2 nd and 3 rd digit and wound on the sole of the right foot since 1 month prior. The patient had history of uncontrolled diabetes since a year ago. She was given ceftriaxone 2 grams b.i.d, metronidazole 500 mg t.i.d empirically and then amikacin 250 mg b.i.d, followed by amputation of the digits and wound debridement. The microorganism′s culture from pus revealed multi drug resistant Pseudomonas putida. She recovered well after antibiotics and surgery.

  16. Selection of antibiotic resistance at very low antibiotic concentrations

    OpenAIRE

    Sandegren, Linus

    2014-01-01

    Human use of antibiotics has driven the selective enrichment of pathogenic bacteria resistant to clinically used drugs. Traditionally, the selection of resistance has been considered to occur mainly at high, therapeutic levels of antibiotics, but we are now beginning to understand better the importance of selection of resistance at low levels of antibiotics. The concentration of an antibiotic varies in different body compartments during treatment, and low concentrations of antibiotics are fou...

  17. Antibiotic alternatives: the substitution of antibiotics in animal husbandry?

    OpenAIRE

    Cheng, Guyue; Hao, Haihong; Xie, Shuyu; Wang, Xu; Dai, Menghong; Huang, Lingli; Yuan, Zonghui

    2014-01-01

    It is a common practice for decades to use of sub-therapeutic dose of antibiotics in food-animal feeds to prevent animals from diseases and to improve production performance in modern animal husbandry. In the meantime, concerns over the increasing emergence of antibiotic-resistant bacteria due to the unreasonable use of antibiotics and an appearance of less novelty antibiotics have prompted efforts to develop so-called alternatives to antibiotics. Whether or not the alternatives could really ...

  18. Antibiotic-Resistant Gonorrhea

    Science.gov (United States)

    ... Search Form Controls Cancel Submit Search the CDC Gonorrhea Note: Javascript is disabled or is not supported ... on Facebook Sexually Transmitted Diseases (STDs) Antibiotic-Resistant Gonorrhea Recommend on Facebook Tweet Share Compartir Low Resolution ...

  19. Glycopeptide antibiotic biosynthesis.

    Science.gov (United States)

    Yim, Grace; Thaker, Maulik N; Koteva, Kalinka; Wright, Gerard

    2014-01-01

    Glycopeptides such as vancomycin, teicoplanin and telavancin are essential for treating infections caused by Gram-positive bacteria. Unfortunately, the dwindled pipeline of new antibiotics into the market and the emergence of glycopeptide-resistant enterococci and other resistant bacteria are increasingly making effective antibiotic treatment difficult. We have now learned a great deal about how bacteria produce antibiotics. This information can be exploited to develop the next generation of antimicrobials. The biosynthesis of glycopeptides via nonribosomal peptide assembly and unusual amino acid synthesis, crosslinking and tailoring enzymes gives rise to intricate chemical structures that target the bacterial cell wall. This review seeks to describe recent advances in our understanding of both biosynthesis and resistance of these important antibiotics.

  20. Antibiotics for uncomplicated diverticulitis

    DEFF Research Database (Denmark)

    Shabanzadeh, Daniel M; Wille-Jørgensen, Peer

    2012-01-01

    Diverticulitis is an inflammatory complication to the very common condition diverticulosis. Uncomplicated diverticulitis has traditionally been treated with antibiotics with reference to the microbiology, extrapolation from trials on complicated intra-abdominal infections and clinical experience....

  1. Antibiotics for sore throat.

    Science.gov (United States)

    Spinks, Anneliese; Glasziou, Paul P; Del Mar, Chris B

    2013-11-05

    Sore throat is a common reason for people to present for medical care. Although it remits spontaneously, primary care doctors commonly prescribe antibiotics for it. To assess the benefits of antibiotics for sore throat for patients in primary care settings. We searched CENTRAL 2013, Issue 6, MEDLINE (January 1966 to July week 1, 2013) and EMBASE (January 1990 to July 2013). Randomised controlled trials (RCTs) or quasi-RCTs of antibiotics versus control assessing typical sore throat symptoms or complications. Two review authors independently screened studies for inclusion and extracted data. We resolved differences in opinion by discussion. We contacted trial authors from three studies for additional information. We included 27 trials with 12,835 cases of sore throat. We did not identify any new trials in this 2013 update. 1. Symptoms Throat soreness and fever were reduced by about half by using antibiotics. The greatest difference was seen at day three. The number needed to treat to benefit (NNTB) to prevent one sore throat at day three was less than six; at week one it was 21. 2. Non-suppurative complications The trend was antibiotics protecting against acute glomerulonephritis but there were too few cases to be sure. Several studies found antibiotics reduced acute rheumatic fever by more than two-thirds within one month (risk ratio (RR) 0.27; 95% confidence interval (CI) 0.12 to 0.60). 3. Suppurative complications Antibiotics reduced the incidence of acute otitis media within 14 days (RR 0.30; 95% CI 0.15 to 0.58); acute sinusitis within 14 days (RR 0.48; 95% CI 0.08 to 2.76); and quinsy within two months (RR 0.15; 95% CI 0.05 to 0.47) compared to those taking placebo. 4. Subgroup analyses of symptom reduction Antibiotics were more effective against symptoms at day three (RR 0.58; 95% CI 0.48 to 0.71) if throat swabs were positive for Streptococcus, compared to RR 0.78; 95% CI 0.63 to 0.97 if negative. Similarly at week one the RR was 0.29 (95% CI 0.12 to 0

  2. 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...

  3. Phenotypic Resistance to Antibiotics

    Directory of Open Access Journals (Sweden)

    Jose L. Martinez

    2013-04-01

    Full Text Available The development of antibiotic resistance is usually associated with genetic changes, either to the acquisition of resistance genes, or to mutations in elements relevant for the activity of the antibiotic. However, in some situations resistance can be achieved without any genetic alteration; this is called phenotypic resistance. Non-inherited resistance is associated to specific processes such as growth in biofilms, a stationary growth phase or persistence. These situations might occur during infection but they are not usually considered in classical susceptibility tests at the clinical microbiology laboratories. Recent work has also shown that the susceptibility to antibiotics is highly dependent on the bacterial metabolism and that global metabolic regulators can modulate this phenotype. This modulation includes situations in which bacteria can be more resistant or more susceptible to antibiotics. Understanding these processes will thus help in establishing novel therapeutic approaches based on the actual susceptibility shown by bacteria during infection, which might differ from that determined in the laboratory. In this review, we discuss different examples of phenotypic resistance and the mechanisms that regulate the crosstalk between bacterial metabolism and the susceptibility to antibiotics. Finally, information on strategies currently under development for diminishing the phenotypic resistance to antibiotics of bacterial pathogens is presented.

  4. Antibiotics produced by Streptomyces.

    Science.gov (United States)

    Procópio, Rudi Emerson de Lima; Silva, Ingrid Reis da; Martins, Mayra Kassawara; Azevedo, João Lúcio de; Araújo, Janete Magali de

    2012-01-01

    Streptomyces is a genus of Gram-positive bacteria that grows in various environments, and its shape resembles filamentous fungi. The morphological differentiation of Streptomyces involves the formation of a layer of hyphae that can differentiate into a chain of spores. The most interesting property of Streptomyces is the ability to produce bioactive secondary metabolites, such as antifungals, antivirals, antitumorals, anti-hypertensives, immunosuppressants, and especially antibiotics. The production of most antibiotics is species specific, and these secondary metabolites are important for Streptomyces species in order to compete with other microorganisms that come in contact, even within the same genre. Despite the success of the discovery of antibiotics, and advances in the techniques of their production, infectious diseases still remain the second leading cause of death worldwide, and bacterial infections cause approximately 17 million deaths annually, affecting mainly children and the elderly. Self-medication and overuse of antibiotics is another important factor that contributes to resistance, reducing the lifetime of the antibiotic, thus causing the constant need for research and development of new antibiotics. Copyright © 2012 Elsevier Editora Ltda. All rights reserved.

  5. Strategies to Minimize Antibiotic Resistance

    Directory of Open Access Journals (Sweden)

    Sang Hee Lee

    2013-09-01

    Full Text Available Antibiotic resistance can be reduced by using antibiotics prudently based on guidelines of antimicrobial stewardship programs (ASPs and various data such as pharmacokinetic (PK and pharmacodynamic (PD properties of antibiotics, diagnostic testing, antimicrobial susceptibility testing (AST, clinical response, and effects on the microbiota, as well as by new antibiotic developments. The controlled use of antibiotics in food animals is another cornerstone among efforts to reduce antibiotic resistance. All major resistance-control strategies recommend education for patients, children (e.g., through schools and day care, the public, and relevant healthcare professionals (e.g., primary-care physicians, pharmacists, and medical students regarding unique features of bacterial infections and antibiotics, prudent antibiotic prescribing as a positive construct, and personal hygiene (e.g., handwashing. The problem of antibiotic resistance can be minimized only by concerted efforts of all members of society for ensuring the continued efficiency of antibiotics.

  6. Infectious Tolerance

    OpenAIRE

    Jonuleit, Helmut; Schmitt, Edgar; Kakirman, Hacer; Stassen, Michael; Knop, Jürgen; Enk, Alexander H.

    2002-01-01

    Regulatory CD4+CD25+ T cells (Treg) are mandatory for maintaining immunologic self-tolerance. We demonstrate that the cell-cell contact–mediated suppression of conventional CD4+ T cells by human CD25+ Treg cells is fixation resistant, independent from membrane-bound TGF-β but requires activation and protein synthesis of CD25+ Treg cells. Coactivation of CD25+ Treg cells with Treg cell–depleted CD4+ T cells results in anergized CD4+ T cells that in turn inhibit the activation of conventional, ...

  7. 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

  8. Interaction of antibacterial compounds with RND efflux pumps in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    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.

  9. 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...

  10. Pseudomona pseudomallei community acquired pneumonia

    International Nuclear Information System (INIS)

    Severiche, Diego

    1998-01-01

    This is the first published case report en Colombia about pseudomona pseudomallei community acquired pneumonia. This uncommon pathogen is from the epidemiological standpoint a very important one and medical community should be aware to look after it in those patients where no other etiological pathogen is recovered. A brief summary about epidemiology is showed, emphasizing those regions where it can be found. Likewise, comments about the differential diagnosis are important since it should be considered in those patients where tuberculosis is suspected. This is particularly representative for countries with high tuberculosis rates. Furthermore, a microbiological review is shown, emphasizing on isolation techniques, descriptions about therapeutics and other regarding treatment issues according international standards. Finally; a description about the clinical picture, laboratory findings, treatment and evolution of the case reported are shown for discussion

  11. Antibiotics, probiotics and prebiotics in IBD.

    Science.gov (United States)

    Bernstein, Charles N

    2014-01-01

    gastrointestinal side effects. Finally, the timing of ingestion of antibiotics and other dietary factors that may function as prebiotics, especially in early childhood, may be critical in shaping the gut microbiome and ultimately predisposing to or preventing IBD. Finding ways to impact on the gut microbiome to alter the course of IBD makes good sense, but should be undertaken in the setting of rigorously performed controlled trials to ensure that the interventions are truly effective and well tolerated. 2014 Nestec Ltd., Vevey/S. Karger AG, Basel.

  12. Glyphosate catabolism by Pseudomonas sp

    International Nuclear Information System (INIS)

    Shinabarger, D.L.

    1986-01-01

    The pathway for the degradation of glyphosate (N-phosphonomethylglycine) by Pseudomonas sp. PG2982 has been determined using metabolic radiolabeling experiments. Radiorespirometry experiments utilizing [3- 14 C] glyphosate revealed that approximately 50-59% of the C3 carbon was oxidized to CO 2 . Fractionation of stationary phase cells labeled with [3- 14 C]glyphosate revealed that from 45-47% of the assimilated C3 carbon is distributed to proteins and that amino acids methionine and serine are highly labeled. The nucleic acid bases adenine and guanine received 90% of the C3 label that was incorporated into nucleic acids, and the only pyrimidine base labeled was thymine. Pulse labeling of PG2982 cells with [3- 14 C]glyphosate revealed that [3- 14 C]sarcosine is an intermediate in glyphosate degradation. Examination of crude extracts prepared from PG2982 cells revealed the presence of an enzyme that oxidizes sarcosine to glycine and formaldehyde. These results indicate that the first step in glyphosate degradation by PG2982 is cleavage of the carbon-phosphorus bond, resulting in the release of sarcosine and a phosphate group. The phosphate group is utilized as a source of phosphorus, and the sarcosine is degraded to glycine and formaldehyde. Phosphonate utilization by Pseudomonas sp. PG2982 was investigated. Each of the ten phosphonates tested were utilized as a sole source of phosphorus by PG2982. Representative compounds tested included alkylphosphonates, 1-amino-substituted alkylphosphonates, amino-terminal phosphonates, and an arylphosphonate. PG2982 cultures degraded phenylphosphonate to benzene and produced methane from methylphosphonate. The data indicate that PG2982 is capable of cleaving the carbon-phosphorus bond of several structurally different phosphonates

  13. Vanillin selectively modulates the action of antibiotics against resistant bacteria.

    Science.gov (United States)

    Bezerra, Camila Fonseca; Camilo, Cicera Janaine; do Nascimento Silva, Maria Karollyna; de Freitas, Thiago Sampaio; Ribeiro-Filho, Jaime; Coutinho, Henrique Douglas Melo

    2017-12-01

    The treatment of infections caused by microorganisms that are resistant to antibiotics represent one of the main challenges of medicine today, especially due to the inefficacy of long-term drug therapy. In the search for new alternatives to treat these infections, many researchers have been looking for new substances derived from natural products to replace, or be used in combination with conventional antibiotics. Vanillin is a phenolic compound whose antimicrobial activity has been used in the elimination of pathogens present in fruits and vegetables. However, its antibacterial and modulating properties remain to be characterized. Therefore, this work aimed to evaluate the antibacterial activity and analyze the modulator activity of vanillin in association with conventional antibiotics. The antimicrobial activity of vanillin was evaluated using the microdilution method to determine the Minimum Inhibitory Concentration (MIC) Standard strains of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and multi-resistant strains of Escherichia coli 06, Staphylococcus aureus 10, Pseudomonas aeruginosa 24 were used in this study. The antibiotic modulating effect was analyzed by combining vanillin with Norfloxacin, Imipenem, Gentamicin, Erythromycin and Tetracycline against the following multiresistant bacteria strains: Escherichia coli 06, Staphylococcus aureus 10 and Pseudomonas aeruginosa 24. Data were analyzed using the ANOVA test of two tracks followed by the post hoc Bonferroni test. Vanillin presented CIMs ≥1024μg/mL against all tested strains demonstrating that it did not present significant antibacterial activity. However, modulated the activity of gentamicin and imipenem against S. aureus and E. coli, causing a synergistic effect, but did not affect the activity of norfloxacin, tetracycline and erythromycin against these same microorganisms. A synergistic effect was also obtained from the association of vanillin with norfloxacin against P

  14. Infectious Tolerance

    Science.gov (United States)

    Jonuleit, Helmut; Schmitt, Edgar; Kakirman, Hacer; Stassen, Michael; Knop, Jürgen; Enk, Alexander H.

    2002-01-01

    Regulatory CD4+CD25+ T cells (Treg) are mandatory for maintaining immunologic self-tolerance. We demonstrate that the cell-cell contact–mediated suppression of conventional CD4+ T cells by human CD25+ Treg cells is fixation resistant, independent from membrane-bound TGF-β but requires activation and protein synthesis of CD25+ Treg cells. Coactivation of CD25+ Treg cells with Treg cell–depleted CD4+ T cells results in anergized CD4+ T cells that in turn inhibit the activation of conventional, freshly isolated CD4+ T helper (Th) cells. This infectious suppressive activity, transferred from CD25+ Treg cells via cell contact, is cell contact–independent and partially mediated by soluble transforming growth factor (TGF)-β. The induction of suppressive properties in conventional CD4+ Th cells represents a mechanism underlying the phenomenon of infectious tolerance. This explains previously published conflicting data on the role of TGF-β in CD25+ Treg cell–induced immunosuppression. PMID:12119350

  15. Antibiotic-modifying activity of riachin, a non-cyanogenic cyanoglycoside extracted from Bauhinia pentandra.

    Science.gov (United States)

    de Farias, Pablo Antonio Maia; Figueredo, Fernando Gomes; Lucas, Aline Maria Brito; de Moura, Rafael Barbosa; Coutinho, Henrique Douglas Melo; da Silva, Tania Maria Sarmento; Martin, Ana Luiza de Aguiar Rocha; Fonteles, Marta Maria de França

    2015-01-01

    The search for new active compounds from the Brazilian flora has intensified in recent years, especially for new drugs with antibiotic potential. Accordingly, the aim of this study was to determine whether riachin has antibiotic activity in itself or is able to modulate the activity of conventional antibiotics. A non-cyanogenic cyanoglycoside known as riachin was isolated from Bauhinia pentandra, and was tested alone and in combination with three antibiotics (clindamycin, amikacin, and gentamicin) against multiresistant bacterial strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). Riachin did not show significant antibiotic activity when tested alone against any strain (P>0.05). However, when combined with conventional antibiotics, it showed drug-modifying activity against strains of S. aureus exposed to clindamycin (P<0.001) as well as against P. aeruginosa exposed to amikacin (P<0.001). Although riachin did not show direct antibiotic activity, it had synergistic activity when combined with amikacin or clindamycin. The mechanism of action of this synergism is under investigation. The results of this work demonstrate that some substances of natural origin can enhance the effectiveness of certain antibiotics, which means a substantial reduction in the drug dose required and possibly in consequent adverse events for patients.

  16. Daily antibiotic cost of nosocomial infections in a Turkish university hospital

    Directory of Open Access Journals (Sweden)

    Yalcin Ata

    2005-01-01

    Full Text Available Abstract Background Many studies associated nosocomial infections with increased hospital costs due to extra days in hospital, staff time, extra investigations and drug treatment. The cost of antibiotic treatment for these infections represents a significant part of hospital expenditure. This prospective observational study was designed to determine the daily antibiotic cost of nosocomial infections per infected adult patient in Akdeniz University Hospital. Methods All adult patients admitted to the ICUs between January 1, 2000, and June 30, 2003 who had only one nosocomial infection during their stay were included in the study. Infection sites and pathogens, antimicrobial treatment of patient and it's cost were recorded. Daily antibiotic costs were calculated per infected patient. Results Among the 8460 study patients, 817 (16.6% developed 1407 episodes of nosocomial infection. Two hundred thirty three (2.7% presented with only one nosocomial infection. Mean daily antibiotic cost was $89.64. Daily antibiotic cost was $99.02 for pneumonia, $94.32 for bloodstream infection, $94.31 for surgical site infection, $52.37 for urinary tract infection, and $162.35 for the other infections per patient. The treatment of Pseudomonas aeruginosa infections was the most expensive infection treated. Piperacillin-tazobactam and amikacin were the most prescribed antibiotics, and meropenem was the most expensive drug for treatment of the nosocomial infections in the ICU. Conclusions Daily antibiotic cost of nosocomial infections is an important part of extra costs that should be reduced providing rational antibiotic usage in hospitals.

  17. Chronic Porcine Two-Hit Model with Hemorrhagic Shock and textitPseudomonas aeruginosa Sepsis

    OpenAIRE

    Eissner, B.;Matz, K.;Smorodchenko, A.;Röschmann, A.;Specht, B. U. v.

    2016-01-01

    Background: Sepsis is still a major cause of death despite well-developed therapeutical strategies such as antibiotics and supportive medication. The aim of this study was to characterize the long-term effects of a two-hit porcine sepsis model with a hemorrhagic shock as ‘first hit’ followed by a Pseudomonas aeruginosa infusion as ‘second hit’. Materials and Methods: Twelve juvenile healthy pigs were anesthetized and hemodynamically monitored. The two-hit group (n = 6) underwent a hemorrhagic...

  18. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-09-20

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

  20. Mutations in 23S rRNA Confer Resistance against Azithromycin in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Marvig, Rasmus Lykke; Søndergaard, Mette S. R.; Pedersen, Søren Damkiær

    2012-01-01

    The emergence of antibiotic-resistant Pseudomonas aeruginosa is an important concern in the treatment of long-term airway infections in cystic fibrosis patients. In this study, we report the occurrence of azithromycin resistance among clinical P. aeruginosa DK2 isolates. We demonstrate that resis...... that resistance is associated with specific mutations (A2058G, A2059G, and C2611T in Escherichia coli numbering) in domain V of 23S rRNA and that introduction of A2058G and C2611T into strain PAO1 results in azithromycin resistance....

  1. Production and characterization of biosurfactant from Pseudomonas ...

    African Journals Online (AJOL)

    Further characterization of biosurfactant using Fourier transform infrared spectroscopy (FTIR) revealed it as a rhamnolipid. Keywords: Mangrove ecosystems, Pseudomonas aeruginosa, biosurfactant, critical micelle concentration (CMC), FT-IR fourier transform infrared spectroscopy (FTIR). African Journal of Biotechnology, ...

  2. 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.

  3. Growth of Pseudomonas fluorescens on Cassava Starch ...

    African Journals Online (AJOL)

    Michael Horsfall

    ABSTRACT: The potential of local strains of microorganism (Pseudomonas fluorescens) in polyhydroxbutyrate production ... The demand for the use of biopolymers ... This work therefore investigates the production of polyhydroxybutyrate from.

  4. August 2014 Phoenix pulmonary journal club: the use of macrolide antibiotics in chronic respiratory disease

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2014-08-01

    Full Text Available No abstract available. Article truncated after 150 words. This month's journal club reviewed the role of macrolide antibiotics in chronic respiratory disease. Macrolide usage was suggested from observational studies in Japan in diffuse panbroncholitis, a disorder associated with chronic respiratory infection, usually Pseudomonas aeruginosa (1. Clinical improvement was noted despite doses of antibiotics well below the minimal inhibitory concentration (MIC of the antibiotic. This suggested the antibiotic was likely working by an anti-inflammatory effect. These observations were extended to cystic fibrosis (CF where prophylactic macrolide therapy in CF patients infected with Pseudomonas has become standard therapy (2. More recently, low dose macrolide therapy has been applied to non-CF lung diseases such as chronic obstructive pulmonary disease (COPD, bronchiectasis and asthma. Time did not permit a review of all studies so a representative sample was discussed. In patients with COPD, the four randomized, placebo-controlled trials reviewed all suggested that chronic therapy with macrolide antibiotics reduced COPD exacerbations (3-5. This ...

  5. Antibiotics for acute bronchitis.

    Science.gov (United States)

    Smith, Susan M; Fahey, Tom; Smucny, John; Becker, Lorne A

    2017-06-19

    The benefits and risks of antibiotics for acute bronchitis remain unclear despite it being one of the most common illnesses seen in primary care. To assess the effects of antibiotics in improving outcomes and to assess adverse effects of antibiotic therapy for people with a clinical diagnosis of acute bronchitis. We searched CENTRAL 2016, Issue 11 (accessed 13 January 2017), MEDLINE (1966 to January week 1, 2017), Embase (1974 to 13 January 2017), and LILACS (1982 to 13 January 2017). We searched the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov on 5 April 2017. Randomised controlled trials comparing any antibiotic therapy with placebo or no treatment in acute bronchitis or acute productive cough, in people without underlying pulmonary disease. At least two review authors extracted data and assessed trial quality. We did not identify any new trials for inclusion in this 2017 update. We included 17 trials with 5099 participants in the primary analysis. The quality of trials was generally good. At follow-up there was no difference in participants described as being clinically improved between the antibiotic and placebo groups (11 studies with 3841 participants, risk ratio (RR) 1.07, 95% confidence interval (CI) 0.99 to 1.15). Participants given antibiotics were less likely to have a cough (4 studies with 275 participants, RR 0.64, 95% CI 0.49 to 0.85; number needed to treat for an additional beneficial outcome (NNTB) 6) and a night cough (4 studies with 538 participants, RR 0.67, 95% CI 0.54 to 0.83; NNTB 7). Participants given antibiotics had a shorter mean cough duration (7 studies with 2776 participants, mean difference (MD) -0.46 days, 95% CI -0.87 to -0.04). The differences in presence of a productive cough at follow-up and MD of productive cough did not reach statistical significance.Antibiotic-treated participants were more likely to be improved according to clinician's global assessment (6 studies

  6. Starvation, Together with the SOS Response, Mediates High Biofilm-Specific Tolerance to the Fluoroquinolone Ofloxacin

    Science.gov (United States)

    Bernier, Steve P.; Lebeaux, David; DeFrancesco, Alicia S.; Valomon, Amandine; Soubigou, Guillaume; Coppée, Jean-Yves; Ghigo, Jean-Marc; Beloin, Christophe

    2013-01-01

    High levels of antibiotic tolerance are a hallmark of bacterial biofilms. In contrast to well-characterized inherited antibiotic resistance, molecular mechanisms leading to reversible and transient antibiotic tolerance displayed by biofilm bacteria are still poorly understood. The physiological heterogeneity of biofilms influences the formation of transient specialized subpopulations that may be more tolerant to antibiotics. In this study, we used random transposon mutagenesis to identify biofilm-specific tolerant mutants normally exhibited by subpopulations located in specialized niches of heterogeneous biofilms. Using Escherichia coli as a model organism, we demonstrated, through identification of amino acid auxotroph mutants, that starved biofilms exhibited significantly greater tolerance towards fluoroquinolone ofloxacin than their planktonic counterparts. We demonstrated that the biofilm-associated tolerance to ofloxacin was fully dependent on a functional SOS response upon starvation to both amino acids and carbon source and partially dependent on the stringent response upon leucine starvation. However, the biofilm-specific ofloxacin increased tolerance did not involve any of the SOS-induced toxin–antitoxin systems previously associated with formation of highly tolerant persisters. We further demonstrated that ofloxacin tolerance was induced as a function of biofilm age, which was dependent on the SOS response. Our results therefore show that the SOS stress response induced in heterogeneous and nutrient-deprived biofilm microenvironments is a molecular mechanism leading to biofilm-specific high tolerance to the fluoroquinolone ofloxacin. PMID:23300476

  7. Biofilm Induced Tolerance Towards Antimicrobial Peptides

    DEFF Research Database (Denmark)

    Folkesson, Anders; Haagensen, Janus Anders Juul; Zampaloni, Claudia

    2008-01-01

    Increased tolerance to antimicrobial agents is thought to be an important feature of microbes growing in biofilms. We address the question of how biofilm organization affects antibiotic susceptibility. We established Escherichia coli biofilms with differential structural organization due...... to the presence of IncF plasmids expressing altered forms of the transfer pili in two different biofilm model systems. The mature biofilms were subsequently treated with two antibiotics with different molecular targets, the peptide antibiotic colistin and the fluoroquinolone ciprofloxacin. The dynamics...... of microbial killing were monitored by viable count determination, and confocal laser microscopy. Strains forming structurally organized biofilms show an increased bacterial survival when challenged with colistin, compared to strains forming unstructured biofilms. The increased survival is due to genetically...

  8. Antibiotic Susceptibility Patterns of Bacterial Isolates from Pus Samples in a Tertiary Care Hospital of Punjab, India

    Directory of Open Access Journals (Sweden)

    Rugira Trojan

    2016-01-01

    Full Text Available We determined the prevalence and antibiotic susceptibilities patterns of bacterial isolates from pus samples collected from patients in a tertiary care hospital of Punjab, India. E. coli was the most prevalent pathogen (51.2% followed by Staphylococcus aureus (21%, Klebsiella pneumoniae (11.6%, Pseudomonas aeruginosa (5.8%, Citrobacter spp. (3.5%, Acinetobacter baumannii (2.3%, Proteus mirabilis (2.3%, and Streptococcus spp. (2.3%. E. coli, K. pneumoniae, A. baumannii, and Citrobacter isolates were resistant to multiple antibiotics including higher generation cephalosporins. S. aureus and Streptococcus isolates were sensitive to cloxacillin and vancomycin. However, P. aeruginosa, P. mirabilis, and Streptococcus isolates were found to be less resistant to the spectrum of antibiotics tested. Overall, our findings indicate the prevalence of resistance to different classes of antibiotics in bacterial isolates from pus infections and hence highlight the need for effective surveillance, regulator reporting, and antibiogram-guided antibiotic prescription.

  9. The multifaceted roles of antibiotics and antibiotic resistance in nature

    Directory of Open Access Journals (Sweden)

    Saswati eSengupta

    2013-03-01

    Full Text Available Antibiotics are chemotherapeutic agents, which have been a very powerful tool in the clinical management of bacterial diseases since the 1940s. However, benefits offered by these magic bullets have been substantially lost in subsequent days following the widespread emergence and dissemination of antibiotic resistant strains. While it is obvious that excessive and imprudent use of antibiotics significantly contributes to the emergence of resistant strains, antibiotic-resistance is also observed in natural bacteria of remote places unlikely to be impacted by human intervention. Both antibiotic biosynthetic genes and resistance-conferring genes have been known to evolve billions of years ago, long before clinical use of antibiotics. Hence it appears that antibiotics and antibiotics resistance determinants have some other roles in nature, which often elude our attention because of overemphasis on the therapeutic importance of antibiotics and the crisis imposed by the antibiotic-resistance in pathogens. In the natural milieu, antibiotics are often found to be present in subinhibitory concentrations acting as signalling molecules supporting quorum sensing and biofilm formation. They also play an important role in the production of virulence factors and influence host-parasite interactions (e.g., phagocytosis, adherence to the target cell and so on. The evolutionary and ecological aspects of antibiotics and antibiotic-resistance in the naturally occurring microbial community are little understood. Therefore, the actual role of antibiotics in nature warrants in-depth investigations. Studies on such an intriguing behaviour of the microorganisms promise insight into the intricacies of the microbial physiology and are likely to provide some lead in controlling the emergence and subsequent dissemination of antibiotic resistance. This article highlights some of the recent findings on the role of antibiotics and genes that confer resistance to antibiotics in

  10. 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...

  11. Hydraphiles enhance antimicrobial potency against Escherichia coli, Pseudomonas aeruginosa, and Bacillus subtilis.

    Science.gov (United States)

    Patel, Mohit B; Garrad, Evan C; Stavri, Ariel; Gokel, Michael R; Negin, Saeedeh; Meisel, Joseph W; Cusumano, Zachary; Gokel, George W

    2016-06-15

    Hydraphiles are synthetic amphiphiles that form ion-conducting pores in liposomal membranes. These pores exhibit open-close behavior when studied by planar bilayer conductance techniques. In previous work, we showed that when co-administered with various antibiotics to the DH5α strain of Escherichia coli, they enhanced the drug's potency. We report here potency enhancements at low concentrations of hydraphiles for the structurally and mechanistically unrelated antibiotics erythromycin, kanamycin, rifampicin, and tetracycline against Gram negative E. coli (DH5α and K-12) and Pseudomonas aeruginosa, as well as Gram positive Bacillus subtilis. Earlier work suggested that potency increases correlated to ion transport function. The data presented here comport with the function of hydraphiles to enhance membrane permeability in addition to, or instead of, their known function as ion conductors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Assessment of strains of Pseudomonas syringae pv. tomato from Tanzania for resistance to copper and streptomycin

    DEFF Research Database (Denmark)

    Shenge, K.C.; Wydra, K.; Mabagala, M.B.

    2008-01-01

    Fifty-six strains of Pseudomonas syringae pv. tomato (P.s. pv. tomato) were collected from tomato-producing areas in Tanzania and assessed for resistance to copper and antibiotics. The collection was done from three tomato-producing regions (Morogoro, Arusha and Iringa), representing three...... different ecological conditions in the country. After isolation and identification, the P. s. pv. tomato strains were grown on King's medium B (KB) amended with 20% copper sulphate (w/v). The strains were also assessed for resistance to antibiotics. Results indicated that there was widespread resistance...... strains of the pathogen were moderately resistant to copper sulphate, such that 54.0% of them were able to grow on the KB medium amended with 20% (w/v) of the copper compound....

  13. [Epidemiologic diagnostic of nosocomial suppurative-septic infections of Pseudomonas etiology based on intraspecies typing of causative agent].

    Science.gov (United States)

    Fel'dblium, I V; Zakharova, Iu A; Nikolaeva, A M; Fedotova, O S

    2013-01-01

    Scientific justification of optimization of epidemiologic diagnostic of suppurative-septic infection (SSI) caused by Pseudomonas aeruginosa based on comparability of antibiotic sensitivity and beta-lactamase production. Intraspecies typing of 37 P. aeruginosa strains isolated during microbiological monitoring of 106 patients and 131 objects of clinical environment of surgical and obstetrician hospitals by using a complex ofphenotypic and molecular-biological methods including determination of sensitivity to antibiotics by serial dilutions method and PCR-diagnostics with determination of TEM, SHV, CTX, OXA, MBL, VIM genes was performed. P. aeruginosa strains combined into groups by isolation location during studies turned out to be heterogeneous by sensitivity to antibiotics and beta-lactamase production that allowed to form subgroups of strains by focality attribute. Isolates recovered from different SSI foci had significant differences in minimal inhibitory concentration (MIC) reaching 1024 times. MIC parameter within subgroups did not exceed 8 - 16 consequent dilutions. Use of a complex of phenotypic and molecular-biologic methods of causative agent typing including determination of sensitivity to antibiotics by serial dilutions method and evaluation of beta-lactamase production allowed to establish a mechanism of development of SSI epidemic process caused by P. aeruginosa, detect origins and reservoirs of infection in hospital, modes and factors of transmission and reach maximum justification of epidemiologic control and prophylaxis measures of localization of foci of nosocomial infections of pseudomonas etiology.

  14. Inhaled antibiotics for lower respiratory tract infections: focus on ciprofloxacin.

    Science.gov (United States)

    Serisier, D J

    2012-05-01

    The administration of antibiotics by the inhaled route offers an appealing and logical approach to treating infectious respiratory conditions. Studies in the cystic fibrosis (CF) population have established the efficacy of this therapeutic concept and inhaled antibiotic therapy is now one of the pillars of management in CF. There are now a number of new inhaled antibiotic formulations that have shown impressive preliminary evidence for efficacy in CF and are commencing phase III efficacy studies. Translation of this paradigm into the non-CF bronchiectasis population has proven difficult thus far, apparently due to problems with tolerability of inhaled formulations. Inhaled versions of ciprofloxacin have shown good tolerability and microbiological efficacy in preliminary studies, suggesting that effective inhaled antibiotics are finally on the horizon for this previously neglected patient population. The increased use of long-term inhaled antibiotics for a wider range of non-CF indications presents risks to the broader community of greater antimicrobial resistance development that must be carefully weighed against any demonstrated benefits. Copyright 2012 Prous Science, S.A.U. or its licensors. All rights reserved.

  15. Profile of antibiotic consumption, sensitivity and resistance in an urban area of Andhra Pradesh, India.

    Science.gov (United States)

    Peripi, Sunita Bhargavi; Thadepalli, Venu Gopala Rao; Khagga, Mukkanti; Tripuraribhatla, Prasanna Krishna; Bharadwaj, Dinesh Kumar

    2012-04-01

    Antibiotics are an important category of drugs in which indiscriminate use can affect the susceptibility patterns among infectious organisms, resulting in antibiotic resistance. Data on antibiotic usage and susceptibility patterns were collected from public and private health centres in Vijayawada, Andhra Pradesh, India, through the use of questionnaires. The data collected were then coded, tabulated, computed and evaluated using statistical analysis. The consumption profile of the different categories of drugs used in public and private hospitals was as follows: nutrition and metabolism products 19.0%; gastrointestinal disorder-related drugs 18.5%; antibiotics 16.8%; anti-pyretics and anti-analgesics 20.6%. These drugs were found to be in high demand. Among the antibiotics, aminoglycosides (amikacin), quinolones (ofloxacin, ciprofloxacin), tetracyclines (doxycycline), penicillin (ampicillin) and sulphonamides (co-trimoxazole) were the most commonly prescribed drugs for antibiotic therapy. 46% of the culture laboratory reports were positive with the following organism profile: Escherichia coli (36%), Klebsiella pneumoniae (16%), Staphylococcus aureus (29%), Enterococcus faecalis (9%) and Pseudomonas aeruginosa (10%). In terms of the sensitivity profile of antibacterials, amikacin (66.9%) was the only antibiotic showing sensitivity patterns, while the majority of antibiotics, such as cotrimoxazole, nalidixic acid, amoxicillin, gentamycin and norfloxacin, had acquired a resistance rate of 55.1%-80.6%. The results of this study suggest that indiscriminate prescription and consumption of new broad-spectrum antibiotics against sensitive organisms results in the development of antimicrobial resistance. Therefore, there is an urgent need to curb the excessive use of antibiotics in local hospitals in order to control the trend of increasing antimicrobial resistance to antibiotics.

  16. Tolerance of staphylococcus aureus to ß-lactam antibiotics

    NARCIS (Netherlands)

    W.H.F. Goessens (Wil)

    1986-01-01

    textabstractPenicillin has a bactericidal action on actively dividing bacteria. If protein synthesis of bacteria exposed to penicillin is inhibited, for example by the addition of chloramphenicol or the omission of an essential amino acid from the medium, the bactericidal action of

  17. Antibiotics and antibiotic resistance in agroecosystems: State of the science

    Science.gov (United States)

    We propose a simple causal model depicting relationships involved in dissemination of antibiotics and antibiotic resistance in agroecosystems and potential effects on human health, functioning of natural ecosystems, and agricultural productivity. Available evidence for each causal link is briefly su...

  18. 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.

  19. OXIDATION OF POLYCHLORINATED BIPHENYLS BY PSEUDOMONAS SP. STRAIN LB400 AND PSEUDOMONAS PSEUDOALCALIGENES KF707

    Science.gov (United States)

    Biphenyl-grown cells and cell extracts prepared from biphenyl-grown cells of Pseudomonas sp. strain LB400 oxidize a much wider range of chlorinated biphenyls than do analogous preparations from Pseudomonas pseudoalcaligenes KF707. These results are attributed to differences in th...

  20. Overdosing on Antibiotics

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Du, a Beijing resident in her 60s, believes that an antibiotic is a panacea for the maladies of her now 6-year-old grand- daughter Guoguo. Du began to take care of her granddaugh- ter since the child was merely 2 months old, for the gid's parents were busy. She is comfortable with her caretaker duties except when the girl runs high fevers. Then, the anxious grandma will feed the girl antibiotics or take her to a private child clinic nearby for intravenous infusion.

  1. Antibiotics in Animal Products

    Science.gov (United States)

    Falcão, Amílcar C.

    The administration of antibiotics to animals to prevent or treat diseases led us to be concerned about the impact of these antibiotics on human health. In fact, animal products could be a potential vehicle to transfer drugs to humans. Using appropri ated mathematical and statistical models, one can predict the kinetic profile of drugs and their metabolites and, consequently, develop preventive procedures regarding drug transmission (i.e., determination of appropriate withdrawal periods). Nevertheless, in the present chapter the mathematical and statistical concepts for data interpretation are strictly given to allow understanding of some basic pharma-cokinetic principles and to illustrate the determination of withdrawal periods

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

    Directory of Open Access Journals (Sweden)

    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.

  3. 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.

  4. Pseudomonas putida KT2440 as a host for biochemicals production

    DEFF Research Database (Denmark)

    Calero Valdayo, Patricia

    The extensive use of cell factories for production of biochemicals is still facing a number of challenges to become economically competitive. One of the problems that need to be overcome is the toxicity of certain chemical products, which prevents yields high enough for their implementation...... in industry.This thesis aims at contributing to developing and characterizing tools for the use of alternative hosts organisms with high tolerance towards toxic compounds, such as Pseudomonas putida. The thesis also focuses on identifying target compounds that may be relevant to produce in this strain...... such as p-coumaric acid, and the mechanisms responsible for such natural tolerance. Moreover, the tolerance towards the highly toxic compound p-hydroxystyrene was improved as an alternative strategy to deal with the effect on growth during the production of such compounds. Expanding the toolbox...

  5. Improving antibiotic use in daily hospital practice : The antibiotic checklist

    NARCIS (Netherlands)

    van Daalen, F.V.

    2018-01-01

    Better use of current antibiotic agents is necessary to help control antimicrobial resistance (AMR). Antibiotic stewardship programs (ASPs) are introduced to coordinate activities to measure and improve appropriate antibiotic use in daily hospital practice. This thesis shows how the introduction of

  6. Fate of antibiotic resistant bacteria and genes during wastewater chlorination: implication for antibiotic resistance control.

    Directory of Open Access Journals (Sweden)

    Qing-Bin Yuan

    Full Text Available This study investigated fates of nine antibiotic-resistant bacteria as well as two series of antibiotic resistance genes in wastewater treated by various doses of chlorine (0, 15, 30, 60, 150 and 300 mg Cl2 min/L. The results indicated that chlorination was effective in inactivating antibiotic-resistant bacteria. Most bacteria were inactivated completely at the lowest dose (15 mg Cl2 min/L. By comparison, sulfadiazine- and erythromycin-resistant bacteria exhibited tolerance to low chlorine dose (up to 60 mg Cl2 min/L. However, quantitative real-time PCRs revealed that chlorination decreased limited erythromycin or tetracycline resistance genes, with the removal levels of overall erythromycin and tetracycline resistance genes at 0.42 ± 0.12 log and 0.10 ± 0.02 log, respectively. About 40% of erythromycin-resistance genes and 80% of tetracycline resistance genes could not be removed by chlorination. Chlorination was considered not effective in controlling antimicrobial resistance. More concern needs to be paid to the potential risk of antibiotic resistance genes in the wastewater after chlorination.

  7. Repressive Tolerance

    DEFF Research Database (Denmark)

    Pedersen, Morten Jarlbæk

    2017-01-01

    Consultation of organised interests and others when drafting laws is often seen as an important source of both input and output legitimacy. But whereas the input side of the equation stems from the very process of listening to societal actors, output legitimacy can only be strengthened if consult......Consultation of organised interests and others when drafting laws is often seen as an important source of both input and output legitimacy. But whereas the input side of the equation stems from the very process of listening to societal actors, output legitimacy can only be strengthened...... a substantial effect on the substance of laws – shows that there is a great difference in the amenability of different branches of government but that, in general, authorities do not listen much despite a very strong consultation institution and tradition. A suggestion for an explanation could be pointing...... to an administrative culture of repressive tolerance of organised interests: authorities listen but only reacts in a very limited sense. This bears in it the risk of jeopardising the knowledge transfer from societal actors to administrative ditto thus harming the consultation institutions’ potential for strengthening...

  8. Bacterial cheating limits antibiotic resistance

    Science.gov (United States)

    Xiao Chao, Hui; Yurtsev, Eugene; Datta, Manoshi; Artemova, Tanya; Gore, Jeff

    2012-02-01

    The widespread use of antibiotics has led to the evolution of resistance in bacteria. Bacteria can gain resistance to the antibiotic ampicillin by acquiring a plasmid carrying the gene beta-lactamase, which inactivates the antibiotic. This inactivation may represent a cooperative behavior, as the entire bacterial population benefits from removing the antibiotic. The cooperative nature of this growth suggests that a cheater strain---which does not contribute to breaking down the antibiotic---may be able to take advantage of cells cooperatively inactivating the antibiotic. Here we find experimentally that a ``sensitive'' bacterial strain lacking the plasmid conferring resistance can invade a population of resistant bacteria, even in antibiotic concentrations that should kill the sensitive strain. We observe stable coexistence between the two strains and find that a simple model successfully explains the behavior as a function of antibiotic concentration and cell density. We anticipate that our results will provide insight into the evolutionary origin of phenotypic diversity and cooperative behaviors.

  9. EDITORIAL THE TREASURE CALLED ANTIBIOTICS

    African Journals Online (AJOL)

    pneumonia, typhoid fever, plaque, tuberculosis, typhus, syphilis, etc. were rampant.1 ... the bacteria to resist the effect of antibiotic for which they were initially ... research and development of new antibiotics, vaccines, diagnostic and other tools.

  10. Antibiotic resistance reservoirs

    NARCIS (Netherlands)

    Versluis, Dennis

    2016-01-01

    One of the major threats to human health in the 21st century is the emergence of pathogenic bacteria that are resistant to multiple antibiotics, thereby limiting treatment options. An important route through which pathogens become resistant is via acquisition of resistance genes from

  11. Mechanisms of Antibiotic Resistance

    Science.gov (United States)

    Munita, Jose M.; Arias, Cesar A.

    2015-01-01

    Emergence of resistance among the most important bacterial pathogens is recognized as a major public health threat affecting humans worldwide. Multidrug-resistant organisms have emerged not only in the hospital environment but are now often identified in community settings, suggesting that reservoirs of antibiotic-resistant bacteria are present outside the hospital. The bacterial response to the antibiotic “attack” is the prime example of bacterial adaptation and the pinnacle of evolution. “Survival of the fittest” is a consequence of an immense genetic plasticity of bacterial pathogens that trigger specific responses that result in mutational adaptations, acquisition of genetic material or alteration of gene expression producing resistance to virtually all antibiotics currently available in clinical practice. Therefore, understanding the biochemical and genetic basis of resistance is of paramount importance to design strategies to curtail the emergence and spread of resistance and devise innovative therapeutic approaches against multidrug-resistant organisms. In this chapter, we will describe in detail the major mechanisms of antibiotic resistance encountered in clinical practice providing specific examples in relevant bacterial pathogens. PMID:27227291

  12. Antibiotic resistance in Salmonella

    NARCIS (Netherlands)

    Vo, A.T.T.

    2007-01-01

    Immediately after their introduction in the beginning of the fourties of the previous century, the agents used to combat infectious diseases caused by bacteria were regarded with suspicion, but not long thereafter antibiotics had the status of miracle drugs. For decades mankind has lived under the

  13. Antibiotic Resistance in Foodborne Pathogens

    OpenAIRE

    Walsh, Ciara; Duffy, Geraldine

    2013-01-01

    Wide-spread antibiotic resistance among bacterial pathogens is now a serious public health issue and multi-antibiotic resistance has been reported in many foodborne pathogens including Salmonella and E. coli. A study to determine antibiotic resistance profiles of a range of Salmonella and Verocytotoxigenic E.coli (VTEC) isolated from Irish foods revealed significant levels of antibiotic resistance in the strains. S. typhimurium DT104 were multiantibiotic resistant with 97% resistant to 7 anti...

  14. Antibiotic resistance in children with recurrent or complicated urinary tract infection.

    Science.gov (United States)

    Younis, N; Quol, K; Al-Momani, T; Al-Awaisheh, F; Al-Kayed, D

    2009-01-01

    Urinary tract infection is certainly one of the most common childhood infections. Emerging resistance to the antibiotics is not unusual. Current hospitalization for children with urinary tract infection is reserved for severe or complicated cases. The aim of the present study was to determine the antibiotic resistance pattern among children with recurrent or complicated urinary tract infection. A retrospective study carried out at Prince Hashem hospital, Zarqa city, eastern Jordan and involved 336 episodes of culture proved urinary tract infection obtained from 121 patients with recurrent UTI, who used prophylactic antibiotics during the period from April 1, 2004 to December 31, 2006. The isolated microorganisms and there antibiotics susceptibility were studied. Seventy three patients (60.3%) were found to have some forms of urinary tract anomaly, significantly more prevalent among male children Purinary tract infection (64.3% vs. 16.6%, Purinary tract infection. Proteus, Pseudomonas and Candida spp. were more prevalent in patients with complicated (Presistant to most antibiotics tested. Pediatric urine culture isolates are becoming increasingly resistant to commonly used antibiotics. Empirical treatment with Trimethoprim-Sulfamethoxazole (TMP-SMX) or Cephalexin as the initial drug is ineffective. Nitrofurantoin and Nalidixic acid can be considered as the first line antibiotics for prophylaxis and or treatment of patients with recurrent UTI, while Meropenam and Ciprofloxacin can be used empirically in treating patients with complicated UTI.

  15. When and How to Take Antibiotics

    Science.gov (United States)

    ... bacterial balance, it may cause stomach upsets, diarrhea, vaginal infections, or other problems. If you take antibiotics unnecessarily ... before taking antibiotics? Antibiotics often lead to a vaginal yeast infection. Because antibiotics kill the normal bacteria in the ...

  16. 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.

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

    Science.gov (United States)

    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.

  18. 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.

  19. Addressing resistance to antibiotics in systematic reviews of antibiotic interventions

    DEFF Research Database (Denmark)

    Leibovici, Leonard; Paul, Mical; Garner, Paul

    2016-01-01

    Antibiotics are among the most important interventions in healthcare. Resistance of bacteria to antibiotics threatens the effectiveness of treatment. Systematic reviews of antibiotic treatments often do not address resistance to antibiotics even when data are available in the original studies....... This omission creates a skewed view, which emphasizes short-term efficacy and ignores the long-term consequences to the patient and other people. We offer a framework for addressing antibiotic resistance in systematic reviews. We suggest that the data on background resistance in the original trials should...... controlled trials or systematic reviews....

  20. Pseudomonas aeruginosa necrotizing chondritis complicating high helical ear piercing case report: clinical and public health perspectives.

    Science.gov (United States)

    Sandhu, Amonpreet; Gross, Melissa; Wylie, John; Van Caeseele, Paul; Plourde, Pierre

    2007-01-01

    Auricular or high helical ear piercing is an increasingly widespread fashion trend that is associated with an increased risk of potentially serious post-piercing complications such as auricular perichondritis. An 11-year-old girl developed severe auricular perichondritis following piercing of the upper helical cartilage of her ear at a hairdressing salon. Four days post piercing, she returned to the same salon for a haircut during which the pierced site was manipulated. She presented to her family physician and was treated unsuccessfully with oral cephalexin. She was then referred to an infectious diseases consultant and received antipseudomonal intravenous antibiotics with subsequent resolution. She also required debridement and removal of necrotic cartilage. Public health investigation evaluated potential sources of infection including the piercing gun, disinfectant solutions, and hair cutting spray water bottles. Final culture results of the ear helical aspirate grew Pseudomonas aeruginosa. Pseudomonas aeruginosa was also cultured from one of the water bottles used to wet her hair during the haircut. Although the pseudomonal strains from the water bottle were different than the infecting one, this contamination presents a potential source of wound infection. Damage to the helical cartilage caused by the piercing gun may also have contributed to this infection. Initial empiric antibiotic therapy for these kinds of infection must include anti-pseudomonal coverage. Auricular or high helical ear piercing using a piercing gun is not recommended.

  1. Early events of lethal action by tobramycin in Pseudomonas aeruginosa

    International Nuclear Information System (INIS)

    Raulston, J.E.

    1988-01-01

    The immediate activities of the aminoglycoside antibiotic, tobramycin, were investigated in Pseudomonas aeruginosa PAO1. The influence of carbon growth substate and the antibiotic exposure environment in the magnitude of activity were examined. Lethality by 8 μg/ml tobramycin occurred rapidly (1 to 3 minutes). The release of specific cellular components into the supernatant was associated with lethality. This material was initially detected as an increase in UV-absorbance. Magnesium in the reaction mixture provided protection against lethality and leakage, but did not reverse lethal damage after a 3 minute tobramycin treatment. Also, uptake of 3 H-tobramycin was reduced in the presence of magnesium. Cells grown with glucose as a carbon source were more susceptible than organic acid grown cells as was the rapidity and amount of cell damage. Analyses of the leakage material revealed a 2-fold increase of protein in the supernatant after a 1-3 minute treatment which paralleled lethality. A prominent 29 kDa protein was observed by SDS-PAGE in the released material, which has been identified as the periplasmic enzyme, β-lactamase. The immediate activities of tobramycin did not involve (i) release of overall cell protein, (ii) massive loss of total pool amino acids, (iii) cell lysis, (iv) inhibition of proline uptake, (v) release of lipopolysaccharide, or (vi) leakage of ATP. Electron microscopy showed no apparent damage after a 3 minute exposure. 40% inhibition of protein synthesis had occurred by 3 minutes of exposure, while release of UV-absorbing material and lethality were detectable after only 1 minute. Resistant cystic fibrosis isolates of P. aeruginosa did not leak under the same experimental conditions, but one of two susceptible strains examined did show increased UV-absorbance following treatment

  2. Environmental pollution by antibiotics and by antibiotic resistance determinants

    International Nuclear Information System (INIS)

    Martinez, Jose Luis

    2009-01-01

    Antibiotics are among the most successful drugs used for human therapy. However, since they can challenge microbial populations, they must be considered as important pollutants as well. Besides being used for human therapy, antibiotics are extensively used for animal farming and for agricultural purposes. Residues from human environments and from farms may contain antibiotics and antibiotic resistance genes that can contaminate natural environments. The clearest consequence of antibiotic release in natural environments is the selection of resistant bacteria. The same resistance genes found at clinical settings are currently disseminated among pristine ecosystems without any record of antibiotic contamination. Nevertheless, the effect of antibiotics on the biosphere is wider than this and can impact the structure and activity of environmental microbiota. Along the article, we review the impact that pollution by antibiotics or by antibiotic resistance genes may have for both human health and for the evolution of environmental microbial populations. - The article reviews the current knowledge on the effects that pollution by antibiotics and antibiotic resistance genes may have for the microbiosphere.

  3. Environmental pollution by antibiotics and by antibiotic resistance determinants

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Jose Luis, E-mail: jlmtnez@cnb.csic.e [Departamento de Biotecnologia Microbiana, Centro Nacional de Biotecnologia, Consejo Superior de Investigaciones Cientificas, Darwin 3, Cantoblanco, 28049 Madrid, and CIBERESP (Spain)

    2009-11-15

    Antibiotics are among the most successful drugs used for human therapy. However, since they can challenge microbial populations, they must be considered as important pollutants as well. Besides being used for human therapy, antibiotics are extensively used for animal farming and for agricultural purposes. Residues from human environments and from farms may contain antibiotics and antibiotic resistance genes that can contaminate natural environments. The clearest consequence of antibiotic release in natural environments is the selection of resistant bacteria. The same resistance genes found at clinical settings are currently disseminated among pristine ecosystems without any record of antibiotic contamination. Nevertheless, the effect of antibiotics on the biosphere is wider than this and can impact the structure and activity of environmental microbiota. Along the article, we review the impact that pollution by antibiotics or by antibiotic resistance genes may have for both human health and for the evolution of environmental microbial populations. - The article reviews the current knowledge on the effects that pollution by antibiotics and antibiotic resistance genes may have for the microbiosphere.

  4. Genotypische diversiteit en rhizosfeerkolonisatie van DAPG-producerende Pseudomonas spp.

    NARCIS (Netherlands)

    Bergsma-Vlami, M.

    2009-01-01

    Het antibioticum 2,4-diacetylphloroglucinol (DAPG) speelt een belangrijke rol in biologische bestrijding van verschillende plantenpathogenen door fluorescerende Pseudomonas-soorten. DAPG-producerende Pseudomonas-stammen zijn effectief in biologische bestrijding, maar hun saprofytisch vermogen is

  5. [The antibacterial activity of oregano essential oil (Origanum heracleoticum L.) against clinical strains of Escherichia coli and Pseudomonas aeruginosa].

    Science.gov (United States)

    Sienkiewicz, Monika; Wasiela, Małgorzata; Głowacka, Anna

    2012-01-01

    The aim of this study was to investigate the antibacterial properties of oregano (Origanum heracleoticum L.) essential oil against clinical strains of Escherichia coli and Pseudomonas aeruginosa. The antibacterial activity of oregano essential oil was investigate against 2 tested and 20 clinical bacterial strains of Escherichia coli and 20 clinical strains o Pseudomonas aeruginosa come from patients with different clinical conditions. The agar dilution method was used for microbial growth inhibition at various concentrations ofoil. Susceptibility testing to antibiotics was carried out using disc-diffusion method. The results of experiments showed that the tested oil was active against all of the clinical strains from both genus of bacteria, but strains of Escherichia coli were more sensitive to tested oil. Essential oil from Origanum heracleoticum L. inhibited the growth of Escherichia coli and Pseudomonas aeruginosa clinical strains with different patters of resistance. The obtained outcomes will enable further investigations using oregano essential oil obtained from Origanum heracleoticum L. as alternative antibacterial remedies enhancing healing process in bacterial infections and as an effective means for the prevention of antibiotic-resistant strain development.

  6. INHALATION ANTIBIOTICS ARE ESSENTIAL FOR THE CONTROL OF INFECTION IN CHILDREN WITH CYSTIC FIBROSIS

    Directory of Open Access Journals (Sweden)

    O.I. Simonova

    2011-01-01

    Full Text Available The article discusses the problem of basis therapy in patients with chronic Pseudomonas aeruginosa infection and cystic fibrosis. Authors showed the safety, good tolerance and high efficacy of constant treatment with special tobramycin solution delivered by nebulizer (Tobi in children including ones under 6 years old. Even first inhalations of tobramycin result in decrease of Pseudomonas aeruginosa rate in bacterial inoculation or to it complete removal. The drug helps stabilization of clinical and functional state of patients, improvement of airflow and common state, and to clinical remission.Key words: children, cystic fibrosis, chronic Pseudomonas aeruginosa infection, tobramycin, nebulizer therapy.(Voprosy sovremennoi pediatrii — Current Pediatrics. 2011; 10 (3: 119–123

  7. Detection Antibiotic Resistance of Enviromental Bacterial Strains

    Directory of Open Access Journals (Sweden)

    Huda Zuheir Majeed

    2018-05-01

    Full Text Available      Antibiotics are randomly prescribed  for veterinary and human medication. Antibiotics by little number are used by human , animals are digested uncompletely  in their digestive system and ended up in communal sewage and hospitals, eventually discharge in environmental water sources directly with no processing.     Water itself consider as major factor of dispersal of bacteria between different environmental components. Besides, bacteria had  transferable genetic mobile elements to different sites of soil, water and humans.       Environmental swabs were collected locally including 50 swabs of hospital environment , 15 samples of poultry feces and chicken guts , 20 sample of heavy water and 15 sample of fish tank to identify16 isolate of Staphylococcus (4 isolate of Staphylococus aureus and 12 isolate of coagulase –ve Staphylococcus , 19 isolate of Enterococcus spp. , 7 isolates of Pseudomonas and 5 environment isolates for each Shigella spp.  and Salmonella spp. .           Teicoplanin and Vancomycin sensitivity test of isolates was done , showing that 2out of 16 isolates of Staphylococcus (12.5% were Vancomycin-resistant , and 3out of 19 isolates of Enterococcus (15.7 % were Vancomycin-resistant, while the rest of isolates were Vancomycin- sensitive. From other side , all isolates was Teicoplanin- sensitive except only 1 Enterococcus spp. Isolate which was intermediate . The range of the Vancomycin MIC were (6-64 µg/ml . Vancomycin resistant isolates , showed that some isolates have one plasmid band after Extraction of their DNA.

  8. 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....

  9. Generic antibiotics in Japan.

    Science.gov (United States)

    Fujimura, Shigeru; Watanabe, Akira

    2012-08-01

    Generic drugs have been used extensively in many developed countries, although their use in Japan has been limited. Generic drugs reduce drug expenses and thereby national medical expenditure. Because generic drugs provide advantages for both public administration and consumers, it is expected that they will be more widely used in the future. However, the diffusion rate of generic drugs in Japan is quite low compared with that of other developed countries. An investigation on generic drugs conducted by the Ministry of Health, Labour and Welfare in Japan revealed that 17.2 % of doctors and 37.2 % of patients had not used generic drugs. The major reasons for this low use rate included distrust of off-patent products and lower drug price margin compared with the brand name drug. The generic drugs available in the market include external drugs such as wet packs, antihypertensive agents, analgesics, anticancer drugs, and antibiotics. Among them, antibiotics are frequently used in cases of acute infectious diseases. When the treatment of these infections is delayed, the infection might be aggravated rapidly. The pharmacokinetics-pharmacodynamics (PK-PD) theory has been adopted in recent chemotherapy, and in many cases, the most appropriate dosage and administration of antibiotics are determined for individual patients considering renal function; high-dosage antibiotics are used preferably for a short duration. Therefore, a highly detailed antimicrobial agent is necessary. However, some of the generic antibiotics have less antibacterial potency or solubility than the brand name products. We showed that the potency of the generic products of vancomycin and teicoplanin is lower than that of the branded drugs by 14.6 % and 17.3 %, respectively. Furthermore, we confirmed that a generic meropenem drug for injection required about 82 s to solubilize in saline, whereas the brand product required only about 21 s. It was thought that the cause may be the difference in size of bulk

  10. Bacterial Community Shift Drives Antibiotic Resistance Promotion during Drinking Water Chlorination.

    Science.gov (United States)

    Jia, Shuyu; Shi, Peng; Hu, Qing; Li, Bing; Zhang, Tong; Zhang, Xu-Xiang

    2015-10-20

    For comprehensive insights into the effects of chlorination, a widely used disinfection technology, on bacterial community and antibiotic resistome in drinking water, this study applied high-throughput sequencing and metagenomic approaches to investigate the changing patterns of antibiotic resistance genes (ARGs) and bacterial community in a drinking water treatment and distribution system. At genus level, chlorination could effectively remove Methylophilus, Methylotenera, Limnobacter, and Polynucleobacter, while increase the relative abundance of Pseudomonas, Acidovorax, Sphingomonas, Pleomonas, and Undibacterium in the drinking water. A total of 151 ARGs within 15 types were detectable in the drinking water, and chlorination evidently increased their total relative abundance while reduced their diversity in the opportunistic bacteria (p < 0.05). Residual chlorine was identified as the key contributing factor driving the bacterial community shift and resistome alteration. As the dominant persistent ARGs in the treatment and distribution system, multidrug resistance genes (mainly encoding resistance-nodulation-cell division transportation system) and bacitracin resistance gene bacA were mainly carried by chlorine-resistant bacteria Pseudomonas and Acidovorax, which mainly contributed to the ARGs abundance increase. The strong correlation between bacterial community shift and antibiotic resistome alteration observed in this study may shed new light on the mechanism behind the chlorination effects on antibiotic resistance.

  11. Antibiotic use and microbiome function.

    Science.gov (United States)

    Ferrer, Manuel; Méndez-García, Celia; Rojo, David; Barbas, Coral; Moya, Andrés

    2017-06-15

    Our microbiome should be understood as one of the most complex components of the human body. The use of β-lactam antibiotics is one of the microbiome covariates that influence its composition. The extent to which our microbiota changes after an antibiotic intervention depends not only on the chemical nature of the antibiotic or cocktail of antibiotics used to treat specific infections, but also on the type of administration, duration and dose, as well as the level of resistance that each microbiota develops. We have begun to appreciate that not all bacteria within our microbiota are vulnerable or reactive to different antibiotic interventions, and that their influence on both microbial composition and metabolism may differ. Antibiotics are being used worldwide on a huge scale and the prescription of antibiotics is continuing to rise; however, their effects on our microbiota have been reported for only a limited number of them. This article presents a critical review of the antibiotics or antibiotic cocktails whose use in humans has been linked to changes in the composition of our microbial communities, with a particular focus on the gut, oral, respiratory, skin and vaginal microbiota, and on their molecular agents (genes, proteins and metabolites). We review the state of the art as of June 2016, and cover a total of circa 68 different antibiotics. The data herein are the first to compile information about the bacteria, fungi, archaea and viruses most influenced by the main antibiotic treatments prescribed nowadays. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. 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...

  13. 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

  14. 21 CFR 866.3415 - Pseudomonas spp. serological reagents.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pseudomonas spp. serological reagents. 866.3415... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3415 Pseudomonas spp. serological reagents. (a) Identification. Pseudomonas spp. serological reagents are devices that...

  15. Prescribing antibiotics in general practice:

    DEFF Research Database (Denmark)

    Sydenham, Rikke Vognbjerg; Pedersen, Line Bjørnskov; Plejdrup Hansen, Malene

    Objectives The majority of antibiotics are prescribed from general practice. The use of broad-spectrum antibiotics increases the risk of development of bacteria resistant to antibiotic treatment. In spite of guidelines aiming to minimize the use of broad-spectrum antibiotics we see an increase...... in the use of these agents. The overall aim of the project is to explore factors influencing the decision process and the prescribing behaviour of the GPs when prescribing antibiotics. We will study the impact of microbiological testing on the choice of antibiotic. Furthermore the project will explore how...... the GPs’ prescribing behaviour is influenced by selected factors. Method The study consists of a register-based study and a questionnaire study. The register-based study is based on data from the Register of Medicinal Product Statistics (prescribed antibiotics), Statistics Denmark (socio-demographic data...

  16. Plant-expressed pyocins for control of Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    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.

  17. Antibiotics and oral contraceptives.

    Science.gov (United States)

    DeRossi, Scott S; Hersh, Elliot V

    2002-10-01

    With the exception of rifampin-like drugs, there is a lack of scientific evidence supporting the ability of commonly prescribed antibiotics, including all those routinely employed in outpatient dentistry, to either reduce blood levels and/or the effectiveness of oral contraceptives. To date, all clinical trials studying the effects of concomitant antibiotic therapy (with the exception of rifampin and rifabutin) have failed to demonstrate an interaction. Like all drugs, oral contraceptives are not 100% effective with the failure rate in the typical United States population reported to be as high as 3%. It is thus possible that the case reports of unintended pregnancies during antibiotic therapy may simply represent the normal failure rate of these drugs. Considering that both drug classes are prescribed frequently to women of childbearing potential, one would expect a much higher rate of oral contraceptive failure in this group of patients if a true drug:drug interaction existed. On the other hand, if the interaction does exist but is a relatively rare event, occurring in, say, 1 in 5000 women, clinical studies such as those described in this article would not detect the interaction. The pharmacokinetic studies of simultaneous antibiotic and oral contraceptive ingestion, and the retrospective studies of pregnancy rates among oral contraceptive users exposed to antibiotics, all suffer from one potential common weakness, i.e., their relatively small sample size. Sample sizes in the pharmacokinetic trials ranged from 7 to 24 participants, whereas the largest retrospective study of pregnancy rates still evaluated less than 800 total contraceptive users. Still, the incidence of such a rare interaction would not differ from the accepted normal failure rate of oral contraceptive therapy. The medico-legal ramifications of what looks like at best a rare interaction remains somewhat "murky." On one hand, we have medico-legal experts advising the profession to exercise caution

  18. Recent advances in the field of 16-membered macrolide antibiotics.

    Science.gov (United States)

    Cui, W; Ma, S

    2011-10-01

    The continuing emergence of bacterial resistance has provided an incentive for recent intensified research on macrolide antibiotics. Belonging to the macrolide family, 16-membered macrolides also experience a renewed interest in further exploration. The medicinal potential of 16-membered macrolides in search for new antibacterials stems from some advantages over 14-membered macrolides, such as gastrointestinal tolerability, structural flexibility, and lack of inducible resistance. Thus, compared with abundant articles on various 14-membered macrolide derivatives in the literature, this review will highlight some representative 16-membered macrolide antibiotics and their recently discovered analogs. Furthermore, the action and resistance mechanisms of 16-membered macrolide antibiotics will be elucidated as well to assist the drug design.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Surveillance of antibiotic resistance

    Science.gov (United States)

    Johnson, Alan P.

    2015-01-01

    Surveillance involves the collection and analysis of data for the detection and monitoring of threats to public health. Surveillance should also inform as to the epidemiology of the threat and its burden in the population. A further key component of surveillance is the timely feedback of data to stakeholders with a view to generating action aimed at reducing or preventing the public health threat being monitored. Surveillance of antibiotic resistance involves the collection of antibiotic susceptibility test results undertaken by microbiology laboratories on bacteria isolated from clinical samples sent for investigation. Correlation of these data with demographic and clinical data for the patient populations from whom the pathogens were isolated gives insight into the underlying epidemiology and facilitates the formulation of rational interventions aimed at reducing the burden of resistance. This article describes a range of surveillance activities that have been undertaken in the UK over a number of years, together with current interventions being implemented. These activities are not only of national importance but form part of the international response to the global threat posed by antibiotic resistance. PMID:25918439

  1. Prophylactic antibiotic therapy for chronic obstructive pulmonary disease (COPD).

    Science.gov (United States)

    Herath, Samantha C; Poole, Phillippa

    2013-11-28

    an exacerbation was reduced (odds ratio (OR) 0.55; 95% confidence interval (CI) 0.39 to 0.77, 3 studies, 1262 participants, high quality). This represented a reduction from 69% of participants in the control group compared to 54% in the treatment group (95% CI 46% to 63%) and the number needed to treat to prevent one exacerbation (NNTb) was therefore 8 (95% CI 5 to 18). The frequency of exacerbations was also reduced with continuous prophylactic antibiotic treatment (rate ratio 0.73; 95% CI 0.58 to 0.91).Use of pulsed antibiotic treatment showed a non-significant reduction in the number of people with exacerbations (OR 0.87; 95% CI 0.69 to 1.09, 1 study, 1149 participants, moderate quality) and the test for interaction showed that this result was significantly different from the effect on exacerbations with continuous antibiotics.There was a statistically significant improvement in quality of life with both continuous and pulsed antibiotic treatment but this was smaller than the four unit improvement that is regarded as being clinically significant (MD -1.78; 95% CI -2.95 to -0.61, 2 studies, 1962 participants, moderate quality).Neither pulsed nor continuous antibiotics showed a significant effect on the secondary outcomes of frequency of hospital admissions, change in lung function, serious adverse events or all-cause mortality (moderate quality evidence).The adverse events that were recorded varied among the trials depending on the different antibiotics used. Azithromycin was associated with a significant hearing loss in the treatment group. The moxifloxacin pulsed study reported a significantly higher number of adverse events in the treatment arm due to the marked increase in gastrointestinal adverse events (P antibiotic resistance in the community is of major concern. One study found newly colonised patients to have higher rates of antibiotic resistance. Patients colonised with moxifloxacin-sensitive pseudomonas at initiation of therapy rapidly became resistant

  2. 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

    Directory of Open Access Journals (Sweden)

    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.

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

    DEFF Research Database (Denmark)

    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....

  4. Menadione (vitamin K enhances the antibiotic activity of drugs by cell membrane permeabilization mechanism

    Directory of Open Access Journals (Sweden)

    Jacqueline C. Andrade

    2017-01-01

    Full Text Available Menadione, vitamin K3, belongs to the class of lipid-soluble vitamins and lipophilic substances as menadione cause disturbances in the bacterial membrane, resulting in damage to the fundamental elements for the integrity of the membrane, thus allowing increased permeability. Accordingly, the aim of this study was to evaluate in vitro the antibiotic-modifying activity of menadione in multiresistant strains of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, with a gradual increase in its subinhibitory concentration. In addition, menadione was compared with cholesterol and ergosterol for similarity in mechanism of drug modulatory action. Antibiotic-modifying activity and antibacterial effect were determined by the broth microdilution assay. Menadione, cholesterol and ergosterol showed modulatory activity at clinically relevant concentrations, characterizing them as modifiers of bacterial drug resistance, since they lowered the MIC of the antibiotics tested. This is the first report of the antibacterial activity of menadione and its potentiation of aminoglycosides against multiresistant bacteria.

  5. Antibiotic resistance of microbial contaminations isolated from husbandry animals and foodstuffs

    Directory of Open Access Journals (Sweden)

    Lukáš Hleba

    2014-05-01

    Full Text Available In this paper the antibiotic resistance of microbial contaminations isolated from husbandry animals and foodstuffs were investigated. Microorganisms isolated from animals and foodstuffs were contaminations of selective media as MacConkey agar for Enterobacteriaceae genera and MRS agar for lactobacilli strains. Microorganisms were isolated and puryfied by agar four ways streak plate method. Identification of isolated microorganisms was done by mass-spectrometry method in MALDI-TOF MS Biotyper. For investigation of antibiotic resistance disc diffusion method by EUCAST was used. In this study Gram-negative and Gram-positive bacteria were identified. The most resistant or multi-resistant bacteria as Pseudomonas aeruginosa, Acinetobacter lwoffi, Lysinibacillus sphaericus, Staphylococcus aureus and Staphylococcus epidermis were determined. Other identified microorganisms were resistant to one antibiotic or not at all.

  6. Antibiotic and synergistic effect of Leu-Lys rich peptide against antibiotic resistant microorganisms isolated from patients with cholelithiasis.

    Science.gov (United States)

    Jeong, Nari; Kim, Jin-Young; Park, Seong-Cheol; Lee, Jong-Kook; Gopal, Ramamourthy; Yoo, Suyeon; Son, Byoung Kwan; Hahm, Joon Soo; Park, Yoonkyung; Hahm, Kyung-Soo

    2010-09-03

    Pseudomonas aeruginosa has eventually developed resistance against flomoxef sodium, isepamicin and cefpiramide. Therefore, in this study, the antibacterial activity and synergistic effects of the amphipathic-derived P5-18mer antimicrobial peptide were tested against pathogens associated with cholelithiasis that have developed resistance against commonly used antibiotics. The results were then compared with the activities of the amphipathic-derived peptide, P5-18mer, melittin and common antibiotics. Growth inhibition of planktonic bacteria was tested using the National Committee for Clinical Laboratory Standards (NCCLS). The bactericidal activity of the antimicrobial peptides was measured using time-kill curves. Synergistic effects were evaluated by testing the effects of P5-18mer alone and in combination with flomoxef sodium, isepamicin or cefpiramide at 0.5xMIC. P5-18mer peptide displayed strong activity against pathogens and flomoxef sodium, isepamicin and cefpiramide-resistant bacteria cell lines obtained from a patient with gallstones; however, it did not exert cytotoxicity against the human keratinocyte HaCat cell line. In addition, the results of time-kill curves indicated that P5-18mer peptide exerted bactericidal activity against four strains of P. aeruginosa. Finally, the use of P5-18mer and antibiotics exerted synergistic effects against cell lines that were resistant to commonly used antibiotics. These results indicate that this class of peptides has a rapid microbicidal effect on flomoxef sodium, isepamicin and cefpiramide-resistant strains of P. aeruginosa. Therefore, these peptides may be used as a lead drug for the treatment of acquired pathogens from patients with cholelithiasis who are affected with antibiotic-resistant bacteria. Copyright 2010 Elsevier Inc. All rights reserved.

  7. 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...

  8. Metabolic regulation of mycobacterial growth and antibiotic sensitivity.

    Directory of Open Access Journals (Sweden)

    Seung-Hun Baek

    2011-05-01

    Full Text Available Treatment of chronic bacterial infections, such as tuberculosis (TB, requires a remarkably long course of therapy, despite the availability of drugs that are rapidly bacteriocidal in vitro. This observation has long been attributed to the presence of bacterial populations in the host that are "drug-tolerant" because of their slow replication and low rate of metabolism. However, both the physiologic state of these hypothetical drug-tolerant populations and the bacterial pathways that regulate growth and metabolism in vivo remain obscure. Here we demonstrate that diverse growth-limiting stresses trigger a common signal transduction pathway in Mycobacterium tuberculosis that leads to the induction of triglyceride synthesis. This pathway plays a causal role in reducing growth and antibiotic efficacy by redirecting cellular carbon fluxes away from the tricarboxylic acid cycle. Mutants in which this metabolic switch is disrupted are unable to arrest their growth in response to stress and remain sensitive to antibiotics during infection. Thus, this regulatory pathway contributes to antibiotic tolerance in vivo, and its modulation may represent a novel strategy for accelerating TB treatment.

  9. Antibiotic resistance in triclosan heterotrophic plate count bacteria from sewage water / Ilsé Coetzee

    OpenAIRE

    Coetzee, Ilsé

    2015-01-01

    The concentration of triclosan in antiseptics, disinfectants and preservatives in products exceeds the minimal lethal levels. Extensive use of triclosan and antibiotics results in bacterial resistance to their active ingredients. The precise relationship between use and resistance, however, has been challenging to define. The aim of the study was to identify and determine antibiotic resistance profiles of triclosan tolerant heterotrophic plate count bacteria isolates from sewag...

  10. An Update on Aerosolized Antibiotics for Treating Hospital-Acquired and Ventilator-Associated Pneumonia in Adults.

    Science.gov (United States)

    Wood, G Christopher; Swanson, Joseph M

    2017-12-01

    A significant percentage of patients with hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) have poor outcomes with intravenous antibiotics. It is not clear if adding aerosolized antibiotics improves treatment. This review is an update on using aerosolized antibiotics for treating HAP/VAP in adults. PubMed search using the terms "aerosolized antibiotics pneumonia," "nebulized antibiotics pneumonia," and "inhaled antibiotics pneumonia." Reference lists from identified articles were also searched. Clinical studies of aerosolized antibiotics for treating HAP/VAP in adults from July 2010 to March 2017. This article updates a previous review on this topic written in mid-2010. The size and quality of studies have improved dramatically in the recent time period compared to previous studies. However, there still are not large randomized controlled trials available. Colistin and aminoglycosides were the most commonly studied agents, and the most common pathogens were Pseudomonas and Acinetobacter. The clinical efficacy of adding aerosolized antibiotics was mixed. Approximately half of the studies showed better outcomes, and none showed worse outcomes. Aerosolized antibiotics appear to be relatively safe, though pulmonary adverse events can occur. Attention to proper administration technique in mechanically ventilated patients is required, including the use of vibrating plate nebulizers. Adding aerosolized antibiotics to intravenous antibiotics may improve the outcomes of adult patients with HAP/VAP in some settings. It seems reasonable to add aerosolized antibiotics in patients with multidrug-resistant organisms or who appear to be failing therapy. Clinicians should pay attention to potential adverse events and proper administration technique.

  11. Novel experimental Pseudomonas aeruginosa lung infection model mimicking long-term host-pathogen interactions in cystic fibrosis

    DEFF Research Database (Denmark)

    Moser, Claus; van Gennip, Maria; Bjarnsholt, Thomas

    2009-01-01

    Moser C, van Gennip M, Bjarnsholt T, Jensen PO, Lee B, Hougen HP, Calum H, Ciofu O, Givskov M, Molin S, Hoiby N. Novel experimental Pseudomonas aeruginosa lung infection model mimicking long-term host-pathogen interactions in cystic fibrosis. APMIS 2009; 117: 95-107. The dominant cause of premature...... death in patients suffering from cystic fibrosis (CF) is chronic lung infection with Pseudomonas aeruginosa. The chronic lung infection often lasts for decades with just one clone. However, as a result of inflammation, antibiotic treatment and different niches in the lungs, the clone undergoes...... and 2003) of the chronic lung infection of one CF patient using the seaweed alginate embedment model. The results showed that the non-mucoid clones reduced their virulence over time, resulting in faster clearing of the bacteria from the lungs, improved pathology and reduced pulmonary production...

  12. Pseudomonas helleri sp. nov. and Pseudomonas weihenstephanensis sp. nov., isolated from raw cow's milk.

    Science.gov (United States)

    von Neubeck, M; Huptas, C; Glück, C; Krewinkel, M; Stoeckel, M; Stressler, T; Fischer, L; Hinrichs, J; Scherer, S; Wenning, M

    2016-03-01

    Analysis of the microbiota of raw cow's milk and semi-finished milk products yielded seven isolates assigned to the genus Pseudomonas that formed two individual groups in a phylogenetic analysis based on partial rpoD and 16S rRNA gene sequences. The two groups could be differentiated from each other and also from their closest relatives as well as from the type species Pseudomonas aeruginosa by phenotypic and chemotaxonomic characterization and average nucleotide identity (ANIb) values calculated from draft genome assemblies. ANIb values within the groups were higher than 97.3 %, whereas similarity values to the closest relatives were 85 % or less. The major cellular lipids of strains WS4917T and WS4993T were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol; the major quinone was Q-9 in both strains, with small amounts of Q-8 in strain WS4917T. The DNA G+C contents of strains WS4917T and WS4993T were 58.08 and 57.30 mol%, respectively. Based on these data, strains WS4917T, WS4995 ( = DSM 29141 = LMG 28434), WS4999, WS5001 and WS5002 should be considered as representatives of a novel species of the genus Pseudomonas, for which the name Pseudomonas helleri sp. nov. is proposed. The type strain of Pseudomonas helleri is strain WS4917T ( = DSM 29165T = LMG 28433T). Strains WS4993T and WS4994 ( = DSM 29140 = LMG 28438) should be recognized as representing a second novel species of the genus Pseudomonas, for which the name Pseudomonas weihenstephanensis sp. nov. is proposed. The type strain of Pseudomonas weihenstephanensis is strain WS4993T ( = DSM 29166T = LMG 28437T).

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

    OpenAIRE

    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...

  14. Biodegradation of chlorpyrifos by bacterial genus Pseudomonas.

    Science.gov (United States)

    Gilani, Razia Alam; Rafique, Mazhar; Rehman, Abdul; Munis, Muhammad Farooq Hussain; Rehman, Shafiq Ur; Chaudhary, Hassan Javed

    2016-02-01

    Chlorpyrifos is an organophosphorus pesticide commonly used in agriculture. It is noxious to a variety of organisms that include living soil biota along with beneficial arthropods, fish, birds, humans, animals, and plants. Exposure to chlorpyrifos may cause detrimental effects as delayed seedling emergence, fruit deformities, and abnormal cell division. Contamination of chlorpyrifos has been found about 24 km from the site of its application. There are many physico-chemical and biological approaches to remove organophosphorus pesticides from the ecosystem, among them most promising is biodegradation. The 3,5,6-trichloro-2-pyridinol (TCP) and diethylthiophosphate (DETP) as primary products are made when chlorpyrifos is degraded by soil microorganisms which further break into nontoxic metabolites as CO(2), H(2)O, and NH(3). Pseudomonas is a diversified genus possessing a series of catabolic pathways and enzymes involved in pesticide degradation. Pseudomonas putida MAS-1 is reported to be more efficient in chlorpyrifos degradation by a rate of 90% in 24 h among Pseudomonas genus. The current review analyzed the comparative potential of bacterial species in Pseudomonas genus for degradation of chlorpyrifos thus, expressing an ecofriendly approach for the treatment of environmental contaminants like pesticides. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Evaluation of gamma irradiation effect and Pseudomonas ...

    African Journals Online (AJOL)

    Antagonistic effect of Pseudomonas fluorescens and influence of gamma irradiation on the development of Penicillium expansum, the causal agent of postharvest disease on apple fruit was studied. P. fluorescens was originally isolated from rhizosphere of the apple trees. Suspension of P. fluorescens and P. expansum ...

  16. Extracytoplasmic function sigma factors in Pseudomonas syringae

    DEFF Research Database (Denmark)

    Kiil, Kristoffer; Oguiza, J.A.; Ussery, D.W.

    2005-01-01

    Genome analyses of the plant pathogens Pseudomonas syringae pv. tomato DC3000, pv. syringae B728a and pv. phaseolicola 1448A reveal fewer extracytoplasmic function (ECF) sigma factors than in related Pseudomonads with different lifestyles. We highlight the presence of a P. syringae-specific ECF...

  17. Optimization of alkaline protease production from Pseudomonas ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-15

    Dec 15, 2009 ... protease production was 37°C at pH 9, with 2% inoculum in the medium for 24 h. .... Positive. Catalase test. Positive ... The enzyme activity gradually decreases from ... Effect of temperature on protease production by Pseudomonas fluorescens. 0 .... between RNA polymerase and upstream promotes DNA.

  18. Comparative evaluation of organic formulations of Pseudomonas ...

    African Journals Online (AJOL)

    An experiment was conducted in the laboratory and farm of the Department of Biotechnology, Gauhati University, to explore the potentiality of various organic formulations of Pseudomonas fluorescens (Pf) and to manage bacterial wilt disease of brinjal (Solanum melongena L.) under local conditions. Different organic ...

  19. High pressure inactivation of Pseudomonas in black truffle - comparison with Pseudomonas fluorescens in tryptone soya broth

    Science.gov (United States)

    Ballestra, Patricia; Verret, Catherine; Cruz, Christian; Largeteau, Alain; Demazeau, Gerard; El Moueffak, Abdelhamid

    2010-03-01

    Pseudomonas is one of the most common genera in black Perigord truffle. Its inactivation by high pressure (100-500 MPa/10 min) applied on truffles at sub-zero or low temperatures was studied and compared with those of Pseudomonas fluorescens in tryptone soya broth. Pressurization of truffles at 300 MPa/4 °C reduced the bacterial count of Pseudomonas by 5.3 log cycles. Higher pressures of 400 or 500 MPa, at 4 °C or 20 °C, allowed us to slightly increase the level of destruction to the value of ca. 6.5 log cycles but did not permit us to completely inactivate Pseudomonas. The results showed a residual charge of about 10 CFU/g. Pressure-shift freezing of truffles, which consists in applying a pressure of 200 MPa/-18 °C for 10 min and then quickly releasing this pressure to induce freezing, reduced the population of Pseudomonas by 3.3 log cycles. The level of inactivation was higher than those obtained with conventional freezing. Endogenous Pseudomonas in truffle was shown to be more resistant to high pressure treatments than P. fluorescens used for inoculation of broths.

  20. Microbial Biofilms: Persisters, Tolerance and Dosing

    Science.gov (United States)

    Cogan, N. G.

    2005-03-01

    Almost all moist surfaces are colonized by microbial biofilms. Biofilms are implicated in cross-contamination of food products, biofouling, medical implants and various human infections such as dental cavities, ulcerative colitis and chronic respiratory infections. Much of current research is focused on the recalcitrance of biofilms to typical antibiotic and antimicrobial treatments. Although the polymer component of biofilms impedes the penetration of antimicrobials through reaction-diffusion limitation, this does not explain the observed tolerance, it merely delays the action of the agent. Heterogeneities in growth-rate also slow the eradication of the bacteria since most antimicrobials are far less effective for non-growing, or slowly growing bacteria. This also does not fully describe biofilm tolerance, since heterogeneities arr primairly a result of nutrient consumption. In this investigation, we describe the formation of `persister' cells which neither grow nor die in the presence of antibiotics. We propose that the cells are of a different phenotype than typical bacterial cells and the expression of the phenotype is regulated by the growth rate and the antibiotic concentration. We describe several experiments which describe the dynamics of persister cells and which motivate a dosing protocol that calls for periodic dosing of the population. We then introduce a mathematical model, which describes the effect of such a dosing regiment and indicates that the relative dose/withdrawal times are important in determining the effectiveness of such a treatment. A reduced model is introduced and the similar behavior is demonstrated analytically.