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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

    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...

  2. 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....

  3. Simultaneous production of alkaline lipase and protease by antibiotic and heavy metal tolerant Pseudomonas aeruginosa.

    Science.gov (United States)

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

    2013-09-01

    An efficient bacterial strain capable of simultaneous production of lipase and protease in a single production medium was isolated. Thirty six bacterial strains, isolated from diverse habitats, were screened for their lipolytic and proteolytic activity. Of these, only one bacterial strain was found to be lipase and protease producer. The 16S rDNA sequencing and phylogenetic analyses revealed that strain (NSD-09) was in close identity to Pseudomonas aeruginosa. The maximum lipase (221.4 U/ml) and protease (187.9 U/ml) activities were obtained after 28 and 24 h of incubation, respectively at pH 9.0 and 37 °C. Castor oil and wheat bran were found to be the best substrate for lipase and protease production, respectively. The strain also exhibited high tolerance to lead (1450 µg/ml) and chromium (1000 µg/ml) in agar plates. It also showed tolerance to other heavy metals, such as Co(+2) , Zn(+2) , Hg(+2) , Ni(+2) and Cd(+2) . Therefore, this strain has scope for tailing bioremediation. Presumably, this is the first attempt on P. aeruginosa to explore its potential for both industrial and environmental applications. PMID:22961768

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

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    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.

  5. 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...

  6. Airway epithelial cell tolerance to Pseudomonas aeruginosa

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    Verghese Margrith W

    2005-04-01

    Full Text Available Abstract Background The respiratory tract epithelium is a critical environmental interface that regulates inflammation. In chronic infectious airway diseases, pathogens may permanently colonize normally sterile luminal environments. Host-pathogen interactions determine the intensity of inflammation and thus, rates of tissue injury. Although many cells become refractory to stimulation by pathogen products, it is unknown whether the airway epithelium becomes either tolerant or hypersensitive in the setting of chronic infection. Our goals were to characterize the response of well-differentiated primary human tracheobronchial epithelial cells to Pseudomonas aeruginosa, to understand whether repeated exposure induced tolerance and, if so, to explore the mechanism(s. Methods The apical surface of well-differentiated primary human tracheobronchial epithelial cell cultures was repetitively challenged with Pseudomonas aeruginosa culture filtrates or the bacterial media control. Toxicity, cytokine production, signal transduction events and specific effects of dominant negative forms of signaling molecules were examined. Additional experiments included using IL-1β and TNFα as challenge agents, and performing comparative studies with a novel airway epithelial cell line. Results An initial challenge of the apical surface of polarized human airway epithelial cells with Pseudomonas aeruginosa culture filtrates induced phosphorylation of IRAK1, JNK, p38, and ERK, caused degradation of IκBα, generation of NF-κB and AP-1 transcription factor activity, and resulted in IL-8 secretion, consistent with activation of the Toll-like receptor signal transduction pathway. These responses were strongly attenuated following a second Pseudomonas aeruginosa, or IL-1β, but not TNFα, challenge. Tolerance was associated with decreased IRAK1 protein content and kinase activity and dominant negative IRAK1 inhibited Pseudomonas aeruginosa -stimulated NF-κB transcriptional

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

    Science.gov (United States)

    Mulyukin, A L; Kozlova, A N; Sorokin, V V; Suzina, N E; Cherdyntseva, T A; Kotova, I B; Gaponov, A M; Tutel'yan, A V; El'-Registan, G I

    2015-01-01

    Survival of bacterial populations treated with lethal doses of antibiotics is ensured by the presence of very small numbers of persister cells. Unlike antibiotic-resistant cells, antibiotic tolerance of persisters is not inheritable and reversible. The present work provides evidence supporting the hypothesis of transformation (maturation) of persisters of an opportunistic pathogen Pseudomonas aeruginosa revealed by ciprofloxacin (CF) treatment (25-100 μg/mL) into dormant cystlike cells (CLC) and non-culturable cells (NC), as was described previously for a number. of non-spore-forming bacteria. Subpopulations of type 1 and type 2 persisters, which survived antibiotic treatment and developed into dormant forms, were heterogeneous in their capacity to form colonies or microcolonies upon germination, in resistance to heating at 70 degrees C, and in cell morphology Type 1 persisters, which were formed after 1-month incubation in the stationary-phase cultures in the medium with decreased C and N concentrations, developed in several types of surviving cells, including those similar to CLC in cell morphology. In the course of 1-month incubation of type 2 persisters, which were formed in exponentially growing cultures, other types of surviving cells developed: immature CLC and L-forms. Unlike P. aeruginosa CLC formed in the control post-stationary phase cultures without antibiotic treatment, most of 1-month persisters, especially type 2 ones, were characterized by the loss of colony-forming capacity, probably due to transition into an uncultured state with relatively high numbers of live intact cells (Live/Dead test). Another survival strategy of P. aeruginosa populations was ensured by a minor subpopulation of CF-tolerant and CF-resistant cells able to grow in the form of microcolonies or regular colonies of decreased size in the presence of the antibiotic. The described P. aeruginosa dormant forms may be responsible for persistent forms in bacteria carriers and latent

  8. Antibiotic tolerance and resistance in biofilms

    DEFF Research Database (Denmark)

    Ciofu, Oana; Tolker-Nielsen, Tim

    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...

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

    OpenAIRE

    D'Arezzo Silvia; Lanini Simone; Puro Vincenzo; Ippolito Giuseppe; Visca Paolo

    2012-01-01

    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...

  10. Isolation of lytic phages for clinical antibiotic resistant Pseudomonas aeruginosa

    OpenAIRE

    Pires, Diana; Sillankorva, Sanna; Faustino, A.; Azeredo, Joana

    2009-01-01

    Pseudomonas aeruginosa is a relevant opportunist pathogen involved in noso-comial infections. P. aeruginosa uses an arsenal of virulence factors to cause serious infections and one of the most worrying characteristics of this bacte-rium is its low antibiotic susceptibility. The low susceptibility to antibiotics can be attributed to a concerted action of multidrug efflux pumps with chromo-somally-encoded antibiotic resistance genes and the low permeability of the bacterial cellular envelopes. ...

  11. Antibiotic Conditioned Growth Medium of Pseudomonas Aeruginosa

    Science.gov (United States)

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

    2004-01-01

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

  12. Tolerance of staphylococci to bactericidal antibiotics.

    Science.gov (United States)

    Vaudaux, Pierre; Lew, Daniel P

    2006-05-01

    Antibiotic therapy for deep-seated staphylococcal infections, especially when they are associated with artificial devices used for orthopedic surgery is often associated with failure. Standard anti-staphylococcal bactericidal antibiotics, such as semi-synthetic penicillins, cephalosporins, or glycopeptides, are effective when given prophylactically in clinical conditions or experimental trials of implant-related infections. However, the efficacy of all anti-staphylococcal agents is seriously diminished on already established implant-related deep-seated infections, which then frequently require surgical implant removal to obtain a cure. The failure of antibiotic therapy to cure established staphylococcal foreign-body infections may arise in part from a broad-spectrum phenotypic tolerance expressed in vivo to different classes of antimicrobial agents. The molecular and physiological mechanisms of this in vivo tolerance remain poorly understood. PMID:16651066

  13. A quorum sensing small volatile molecule promotes antibiotic tolerance in bacteria.

    Directory of Open Access Journals (Sweden)

    Yok-Ai Que

    Full Text Available Bacteria can be refractory to antibiotics due to a sub-population of dormant cells, called persisters that are highly tolerant to antibiotic exposure. The low frequency and transience of the antibiotic tolerant "persister" trait has complicated elucidation of the mechanism that controls antibiotic tolerance. In this study, we show that 2' Amino-acetophenone (2-AA, a poorly studied but diagnostically important small, volatile molecule produced by the recalcitrant gram-negative human pathogen Pseudomonas aeruginosa, promotes antibiotic tolerance in response to quorum-sensing (QS signaling. Our results show that 2-AA mediated persister cell accumulation occurs via alteration of the expression of genes involved in the translational capacity of the cell, including almost all ribosomal protein genes and other translation-related factors. That 2-AA promotes persisters formation also in other emerging multi-drug resistant pathogens, including the non 2-AA producer Acinetobacter baumannii implies that 2-AA may play an important role in the ability of gram-negative bacteria to tolerate antibiotic treatments in polymicrobial infections. Given that the synthesis, excretion and uptake of QS small molecules is a common hallmark of prokaryotes, together with the fact that the translational machinery is highly conserved, we posit that modulation of the translational capacity of the cell via QS molecules, may be a general, widely distributed mechanism that promotes antibiotic tolerance among prokaryotes.

  14. Identification of Pseudomonas aeruginosa genes associated with antibiotic susceptibility

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Pseudomonas aeruginosa causes acute and chronic infections in humans and these infections are difficult to treat due to the bacteria’s high-level of intrinsic and acquired resistance to antibiotics. To address this problem, it is crucial to investigate the molecular mechanisms of antibiotic resistance in this organism. In this study, a P. aeruginosa transposon insertion library of 17000 clones was constructed and screened for altered susceptibility to seven antibiotics. Colonies grown on agar plates con- taining antibiotics at minimum inhibitory concentrations (MICs) and those unable to grow at ? MIC were collected. The transposon-disrupted genes in 43 confirmed mutants that showed at least a three-fold increase or a two-fold decrease in suscep- tibility to at least one antibiotic were determined by semi-random PCR and subsequent sequencing analysis. In addition to nine genes known to be associated with antibiotic resistance, including mexI, mexB and mexR, 24 new antibiotic resis- tance-associated genes were identified, including a fimbrial biogenesis gene pilY1 whose disruption resulted in a 128-fold in- crease in the MIC of carbenicillin. Twelve of the 43 genes identified were of unknown function. These genes could serve as targets to control or reverse antibiotic resistance in this important human pathogen.

  15. 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

  16. Study on Antibiotic compounds from Pseudomonas aeruginosa NO4 Strain

    International Nuclear Information System (INIS)

    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

  17. ACTINOMYCETES: TOLERANCE AGAINST HEAVY METALS AND ANTIBIOTICS

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    Smriti Singh, Shruti Pandey and Hotam Singh Chaudhary*

    2014-09-01

    Full Text Available Heavy metals can be both, essential as well as toxic for living beings. Micronutrients such as, Co, Fe, Mn have important role to play in living systems whereas, Pb Cd etc. pose harmful effects even at low concentrations. When these heavy metals get accumulated within the tissues of the organisms at various levels of the ecological chain, they cause decrease in the biomass and biological diversity by affecting the growth, morphology and activity of the organisms. Accumulation of heavy metals in soil also causes soil contamination, which can be overcome with the help of bioremediation. A large group of soil bacteria belonging to the Actinomycetes species are exposed to heavy metals in a variety of ways; although, they show resistance to heavy metals. The species of actinomycetes possess resistance for antibiotic synthesis as well. This makes the actinomycetes suitable agents for bioremediation. In this experiment, a total of 20 isolates from Shivpuri region of Madhya Pradesh were tested for the metal tolerance against selected heavy metals. After this, the most tolerant strains were tested to check their antibiotic susceptibility. Metal tolerance was tested by agar well diffusion method and tube dilution method. Out of the 20 isolates, Ash1, Ash 2, Ash 4,Ash 6, Ash 7, Ash 8, Ash 9, Ash 10, Ash 11, Ash 12, Ash 13, Ash 15 were resistant at 10 mM conc. of CuSo4, but their growth was inhibited at higher concentrations of metal salts. Isolates Ash 10, Ash 11, Ash 12, Ash 13, Ash 19, Ash 20 were found to be resistant at 10mM conc. of ZnSO4, but they were also inhibited at higher concentrations. For different concentrations of Pb(CH3COO2 most of the isolates showed same level of tolerance.

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

    Science.gov (United States)

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

    2016-01-01

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

  19. Synergic interaction between ascorbic acid and antibiotics against Pseudomonas aeruginosa

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    Luciana Cursino

    2005-05-01

    Full Text Available Studies were carried out on in vitro combination of ascorbic acid (AA with six antibiotics against 12 multi-resistant Pseudomonas aeruginosa isolates. Synergic activity was detected with AA chloramphenicol, kanamycin, streptomycin and tetracycline. Indifference was observed to any antibiotics and antagonism only for chloramphenicol. Results indicated that multiresistant P. aeruginosa was affected by combination of AA and antibiotics. Future research on ascorbic acid-antimicrobial interactions may find new methods to control strains of multiresistant P. aeruginosa.Investigou-se in vitro o efeito da combinação do ácido ascórbico (AA com seis antibióticos frente a 12 isolados multirresistentes de Pseudomonas aeruginosa. As concentrações inibitórias mínimas (CIM foram determinadas pelo método de diluição em caldo. Foi estudado o efeito do AA nas CIM pelo cálculo das concentrações inibitórias fracionais (CIF. Para quase todas as combinações AA-antibiótico foi detectado efeito sinérgico, exceto para ampicilina e tobramicina. Indiferença foi observada na interação com todos os antibióticos, porém antagonismo foi somente observado para cloranfenicol. Os resultados deste estudo indicam que o sinergismo contra P. aeruginosa resistentes pode ocorrer entre AA e cloranfenicol, canamicina, estreptomicina e tetraciclina, ainda que as linhagens sejam resistentes aos antibióticos individualmente. Além disso, estes resultados encorajam futuros trabalhos in vivo a respeito da interação AA-antimicrobianos na incessante busca de novas alternativas para o controle de linhagens multirresistentes de P.aeruginosa.

  20. The resistance of Enterobacteriaceae members and Pseudomonas species to p-laktam antibiotics

    OpenAIRE

    Durmaz, Dr. Bengül; ÖZEROL, Dr. İ Halil; Şahin, Dr. Kazını; Tekerekoğlu, Dr. M. Sait; Köroğlu, Dr. Mehmet

    1997-01-01

    This study was performed in İnönü University Turgut ÖZAL Medical Center to asses the resistance of Enterobacteriaceae and Pseudomonas species to P-laktam antibiotics. From October 1995 to February 1997, 1126 Gram negative bacilli were isolated. 1022 (91) of isolates were Enterobacteriaceae members whereas 104 (9%) of them were Pseudomonas species. Sensitivities of pathogens P-laktam antibiotics were performed by Kirby-Bauer disc diffusion method. Following antibiotics were effective as: cefta...

  1. 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...

  2. Bile signalling promotes chronic respiratory infections and antibiotic tolerance.

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    Reen, F Jerry; Flynn, Stephanie; Woods, David F; Dunphy, Niall; Chróinín, Muireann Ní; Mullane, David; Stick, Stephen; Adams, Claire; O'Gara, Fergal

    2016-01-01

    Despite aggressive antimicrobial therapy, many respiratory pathogens persist in the lung, underpinning the chronic inflammation and eventual lung decline that are characteristic of respiratory disease. Recently, bile acid aspiration has emerged as a major comorbidity associated with a range of lung diseases, shaping the lung microbiome and promoting colonisation by Pseudomonas aeruginosa in Cystic Fibrosis (CF) patients. In order to uncover the molecular mechanism through which bile modulates the respiratory microbiome, a combination of global transcriptomic and phenotypic analyses of the P. aeruginosa response to bile was undertaken. Bile responsive pathways responsible for virulence, adaptive metabolism, and redox control were identified, with macrolide and polymyxin antibiotic tolerance increased significantly in the presence of bile. Bile acids, and chenodeoxycholic acid (CDCA) in particular, elicited chronic biofilm behaviour in P. aeruginosa, while induction of the pro-inflammatory cytokine Interleukin-6 (IL-6) in lung epithelial cells by CDCA was Farnesoid X Receptor (FXR) dependent. Microbiome analysis of paediatric CF sputum samples demonstrated increased colonisation by P. aeruginosa and other Proteobacterial pathogens in bile aspirating compared to non-aspirating patients. Together, these data suggest that bile acid signalling is a leading trigger for the development of chronic phenotypes underlying the pathophysiology of chronic respiratory disease. PMID:27432520

  3. Antibiotic resistance patterns of Pseudomonas spp. isolated from the River Danube

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    Clemens eKittinger

    2016-05-01

    Full Text Available Spread and persistence of antibiotic resistance pose a severe threat to human health, yet there is still lack of knowledge about reservoirs of antibiotic resistant bacteria in the environment. We took the opportunity of the Joint Danube Survey 3 (JDS3, the world's biggest river research expedition of its kind in 2013, to analyse samples originating from different sampling points along the whole length of the river. Due to its high clinical relevance, we concentrated on the characterization of Pseudomonas spp. and evaluated the resistance profiles of Pseudomonas spp. which were isolated from eight sampling points. In total, 520 Pseudomonas isolates were found, 344 (66.0% isolates were identified as Pseudomonas putida, and 141 (27.1% as Pseudomonas fluorescens, all other Pseudomonas species were represented by less than five isolates, among those two P. aeruginosa isolates. Thirty seven percent (37% of all isolated Pseudomonas species showed resistance to at least one out of eleven tested antibiotics. The most common resistance was against meropenem (30.4% / 158 isolates piperacillin/tazobactam (10.6% / 55 isolates and ceftazidime (4.2% / 22 isolates. 16 isolates (3.1% / 16 isolates were multi-resistant. For each tested antibiotic at least one resistant isolate could be detected. Sampling points from the upper stretch of the River Danube showed more resistant isolates than downriver. Our results suggest that antibiotic resistance can be acquired by and persists even in Pseudomonas species that are normally not in direct contact with humans. A possible scenario is that these bacteria provide a reservoir of antibiotic resistance genes that can spread to related human pathogens by horizontal gene transfer.

  4. Cell motility and antibiotic tolerance of bacterial swarms

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    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.

  5. Membrane localization and topology of the DnpA protein control fluoroquinolone tolerance in Pseudomonas aeruginosa.

    Science.gov (United States)

    Liebens, Veerle; Frangipani, Emanuela; Van der Leyden, Annelies; Fauvart, Maarten; Visca, Paolo; Michiels, Jan

    2016-09-01

    DnpA, a putative de-N-acetylase of the PIG-L superfamily, is required for antibiotic tolerance in Pseudomonas aeruginosa Exactly how dnpA (gene locus PA5002) directs the formation of antibiotic-tolerant persister cells is currently unknown. Previous research provided evidence for a role in surface-associated process(es), possibly in lipopolysaccharide biosynthesis. In silico sequence analysis of DnpA predicts a single transmembrane domain and Nin/Cout orientation of DnpA. In contrast, we here show that DnpA is an integral inner membrane protein containing two transmembrane domains, with the major C-terminal part located at the cytoplasmic face. Correct insertion into the inner membrane is necessary for DnpA to promote fluoroquinolone tolerance. The membrane localization of DnpA further supports its role in cell envelope-associated process(es). In addition to shedding light on the biological role of DnpA, this study highlights the risks of overreliance on the predictive value of bioinformatics tools and the importance of rigorous experimental validation of in silico predictions. PMID:27481702

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

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    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.

  7. In vitro Evaluation of Antibacterial Efficacy of Natural Honeys in Comparison with Antibiotics on Pseudomonas aeruginosa

    OpenAIRE

    Vahid Yavarpour; Mehdi Zarabi; Davoud Esmaeili; Javad Mohamadnejad

    2014-01-01

    Background and Aim: Several studies have been done that showed honey has been therapeutic effects on infection disease like Pseudomonas infections. Our aim of this study is evaluation of the antibacterial activity of mono floral and multi floral honeys from different origin of Iran on growth of Pseudomonas aeruginosa and compare their activities with artificial honey and antibiotics. Materials and Methods: Antimicrobial effect of honey was determined by disc diffusion and broth dilution metho...

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

    Science.gov (United States)

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

    2016-05-01

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

  9. Effects of antibiotics on quorum sensing in pseudomonas aeruginosa

    DEFF Research Database (Denmark)

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

    2008-01-01

    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...... 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 by....... 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...

  10. Retrospective analysis of antibiotic susceptibility patterns of respiratory isolates of Pseudomonas aeruginosa in a Turkish University Hospital

    OpenAIRE

    Akkurt Ibrahim; Ozdemir Levent; Bakici Mustafa; Gonlugur Ugur; Icagasioglu Serhat; Gultekin Fusun

    2003-01-01

    Abstract Background Lower respiratory tract infections due to Pseudomonas aeruginosa have a high mortality rate. Antibacterial activity of various antibiotics against P. aeruginosa isolated from each hospital depends on the variety or amount of antibiotics used in each hospital. Method A total of 249 respiratory isolates of Pseudomonas aeruginosa in Sivas (Turkey) were included between January-1999 and January-2002. Isolates were tested against 14 different antibiotics by a disc diffusion met...

  11. Antibiotic resistance in clinical isolates of Pseudomonas aeruginosa in Jamaica Resistencia a antibióticos en cepas clínicas de Pseudomonas aeruginosa en Jamaica

    OpenAIRE

    Brown, Paul D.; Anicetus Izundu

    2004-01-01

    OBJECTIVE: To assess antibiotic resistance in clinical isolates of Pseudomonas aeruginosa in Jamaica, and to obtain baseline information on the presence of this important pathogen. METHODS: A total of 51 isolates of Pseudomonas aeruginosa, obtained from 162 clinical specimens from major hospitals and laboratories in seven parishes in Jamaica, were analyzed between May and August 2002. Isolates were tested against 18 different antibiotics by a disk diffusion method. RESULTS: Organisms were cul...

  12. Antibiotic Resistance Determinants in a Pseudomonas putida Strain Isolated from a Hospital

    OpenAIRE

    Molina, Lázaro; Udaondo, Zulema; Duque, Estrella; Fernández, Matilde; Molina-Santiago, Carlos; Roca, Amalia; Porcel, Mario; de la Torre, Jesús; Segura, Ana; Plesiat, Patrick; Jeannot, Katy; Ramos, Juan-Luis

    2014-01-01

    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...

  13. Comparisons of antibiotic combinations to control Pseudomonas aeruginosa in bovine semen.

    OpenAIRE

    EAGLESOME, M.D.; Garcia, M M

    1995-01-01

    Raw semen experimentally contaminated with 10(6) Pseudomonas aeruginosa cells per milliliter was processed for use in artificial insemination (AI) using three different antibiotic combinations: a) gentamicin, lincomycin, spectinomycin and tylosin (GLST) directly added to contaminated raw semen followed by dilution with whole milk or egg yolk Tris containing GLST; b) penicillin, streptomycin, lincomycin, spectinomycin and minocycline (PSLSM) in whole milk used to dilute the contaminated raw se...

  14. ANTIBIOTIC RESISTANCE PATTERN IN PSEUDOMONAS AERUGINOSA SPECIES ISOLATED AT INDORE (M.P.

    Directory of Open Access Journals (Sweden)

    Prafulla

    2014-01-01

    Full Text Available INTRODUCTION : Pseudomonas aeruginosa is an aerobic , motile , gram negative rod that belongs to the family , pseudomonadaceae 2 . Its general resistance is due to a combination of factors 3 .Regional variations in the antibiotic resistance exist for different organisms , including P. aeruginosa and this may be related to the difference in the antibiotic prescribing habits. So , we a imed in the present study , to determine the status of antimicrobial resistance to anti - pseudomonadal agents and the magnitude of the multidrug r esistance in these organisms. MATERIALS AND METHODS : This study was conducted during 1 st January 2013 to 30 th September 2013. During this period total of 5877 samples were tested , out of 5877 samples , 1693 samples showed growth on culture and out of 1693 sa mples , 152 Pseudomonas aeruginosa were isolated. Identification & sensitivity of all isolates were done by BD Phoenix TM Automated Microbiological System. The antibiotics which were include d in the panel were ciprofloxacin , levofloxacin , gentamicin , amikaci n , tobramycin , aztreonam , ceftazidime , cefepime , piperacillin , piperacillin/tazobactam , ticarcillin/tazobactam , imipenem , meropenem and colistin according to CLSIs guidelines. RESULT : In the present study , the highest number s of Pseudomonas infections was found in pus followed by urine and Endotracheal secretion. Pseudomonas aeruginosa isolated from various samples were resistant to aztreonam , ciprofloxacin followed by levofloxacin , ceftazidime , cefepime , amikacin , imipenem & colistin. CONCLUSION : To preven t the spread of the resistant bacteria , it is critically important to have strict antibiotic policies wherein surveillance programmes for multidrug resistant organisms and infection control procedures need to be implemented

  15. Phylogenetic Distribution of CRISPR-Cas Systems in Antibiotic-Resistant Pseudomonas aeruginosa

    OpenAIRE

    van Belkum, Alex; Soriaga, Leah B.; LaFave, Matthew C.; Akella, Srividya; Veyrieras, Jean-Baptiste; Barbu, E. Magda; Shortridge, Dee; Blanc, Bernadette; Hannum, Gregory; Zambardi, Gilles; Miller, Kristofer; Enright, Mark C; Mugnier, Nathalie; Brami, Daniel; Schicklin, Stéphane

    2015-01-01

    ABSTRACT Pseudomonas aeruginosa is an antibiotic-refractory pathogen with a large genome and extensive genotypic diversity. Historically, P. aeruginosa has been a major model system for understanding the molecular mechanisms underlying type I clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated protein (CRISPR-Cas)-based bacterial immune system function. However, little information on the phylogenetic distribution and potential role of these CRISPR-Cas syste...

  16. Investigating Antibiotic Resistance in Pseudomonas Aeruginosa Strains Isolated from Various Clinical Specimens of Patients Referring to Hospitals in Yazd

    Directory of Open Access Journals (Sweden)

    M Kiani

    2015-02-01

    Full Text Available Introduction: Antibiotic resistance in Pseudomonas aeruginosa has become a worldwide problem, and is leading to multi-drug resistance (MDR: Multiple drug resistance. Therefore, this study aimed to determine the antibiotic strain patterns of Pseudomonas aeruginosa isolated from various clinical specimens of patients in hospitals in Yazd. Methods: In this descriptive cross- sectional study, 90 isolates of pseudomonas aeruginosa derived from different clinical samples was transferred to the microbiology lab of Shahid Sadoughi University of Medical Sciences in Yazd in 2013. Conventional biochemical tests were utilized to confirm the presence of bacteria, and then antibiotic resistance pattern was determined using standard disk diffusion (Kirby - Bauer method according to the CLSI guideline. Results: Out of 90 isolates of Pseudomonas aeruginosa isolated from various clinical samples, burn wound specimens had the most antibiotic-resistant pattern. As a matter of fact, all of 28 strains isolated from burn wounds were MDR. Ceftazidime involved the most resistant antibiotic (56%, whereas ciprofloxacin was the least resistant one (44.4%, and 66.6% of the isolates were detected as multi-drug resistant. Conclusion: The prevalence of MDR Pseudomans aeruginosa in the present study was high. As ceftazidime, Ertapenem, and meropenem had effective anti Pseudomonal activity against MDR Pseudomans aeruginosa (in this study increased resistance to these antibiotics was observed, it is necessary to evaluate antibiotic susceptibility as well as to determine antibiotic pattern prior to starting the treatment in order to prevent antibiotic-resistant strains.

  17. 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.

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

    Science.gov (United States)

    Molina, Lázaro; Udaondo, Zulema; Duque, Estrella; Fernández, Matilde; Molina-Santiago, Carlos; Roca, Amalia; Porcel, Mario; de la Torre, Jesús; Segura, Ana; Plesiat, Patrick; Jeannot, Katy; Ramos, Juan-Luis

    2014-01-01

    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. PMID:24465371

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

    Science.gov (United States)

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

    2016-01-01

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

  20. Lead tolerance capacity of clinical bacterial isolates and change in their antibiotic susceptibility pattern after exposure to a heavy metal

    Directory of Open Access Journals (Sweden)

    Divya Garhwal

    2014-07-01

    Full Text Available Introduction: Heavy metal pollutions of soil and wastewater are a significant environmental problem as they are not degraded or destroyed. Several metal resistance mechanisms have been identified which is responsible for alteration of normal cell physiology leading to development of drug resistance in microorganisms. Heavy metals used in industry and in household products are, along with antibiotics, creating a selective pressure in the environment that leads to the mutations in microorganisms. The present study was carried out to study the heavy metal lead tolerance by bacteria and change in antibiotic-sensitivity pattern after its exposure. Materials and Methods: 30 clinical isolates from various samples received in the Department of Microbiology, Government Medical College, Surat, were included in the study. To check the lead tolerance capacity, isolates were exposed to graded concentration of lead nitrate by plate dilution method, starting from 50 up to 1000 μg/ml strength. Antibiotic susceptibility was performed by the Kirby Bauer disc diffusion method. A change in antibiotic susceptibility pattern was studied before and after lead exposure. Result: 30 clinical isolates were included in the study, 25 Gram negative (83.3% and 5 Gram positive (16.7%. MIC to lead was higher in Acinetobacter spp. and Pseudomonas spp. (600-1000 μg/ml as compared to E. coli, Klebsiella spp., S. aureus (50-150 μg/ml. Multiple antibiotic resistance indexes were changed significantly after lead exposure. Conclusion: Bacteria exposed to high levels of heavy metals in their environment have adapted to this stress by developing various resistance mechanism. Infection with antibiotic-resistant organisms create problem in treatment and management of patients. We should take efforts to prevent environmental pollution with such heavy metals and transmission of antibiotic-resistant microorganism from environment to health care set up.

  1. Antibiotic and metal resistance in a ST395 Pseudomonas aeruginosa environmental isolate: A genomics approach.

    Science.gov (United States)

    Teixeira, Pedro; Tacão, Marta; Alves, Artur; Henriques, Isabel

    2016-09-15

    We analyzed the resistome of Pseudomonas aeruginosa E67, an epiphytic isolate from a metal-contaminated estuary. The aim was to identify genetic determinants of resistance to antibiotics and metals, assessing possible co-selection mechanisms. Identification was based on phylogenetic analysis and average nucleotide identity value calculation. MLST affiliated E67 to ST395, previously described as a high-risk clone. Genome analysis allowed identifying genes probably involved in resistance to antibiotics (e.g. beta-lactams, aminoglycosides and chloramphenicol) and metals (e.g. mercury and copper), consistent with resistance phenotypes. Several genes associated with efflux systems, as well as genetic determinants contributing to gene motility, were identified. Pseudomonas aeruginosa E67 possesses an arsenal of resistance determinants, probably contributing to adaptation to a polluted ecosystem. Association to mobile structures highlights the role of these platforms in multi-drug resistance. Physical links between metal and antibiotic resistance genes were not identified, suggesting a predominance of cross-resistance associated with multidrug efflux pumps. PMID:27371958

  2. Frequency of Pseudomonas aeruginosa serotypes in burn wound infections and their resistance to antibiotics.

    Science.gov (United States)

    Estahbanati, Hamid Karimi; Kashani, Parnian Pour; Ghanaatpisheh, Fahimeh

    2002-06-01

    Pseudomonas aeruginosa plays a prominent role as an etiological agent involved in serious infections in burned patients. In this study P. aeruginosa infections were analyzed at the Motahari Burn Center in Tehran (from 22 December 1998 to April 1999) to estimate their frequency, antibiotic susceptibility and serotypes. One hundred and eighty-four positive cultures and 205 bacterial strains were isolated among swabs or biopsy specimens during the study period. Pseudomonas was found to be the most common (57%) followed by Acinetobacter (17%), Escherichia coli (12%), Staphylococcus aureus (8%) and other organisms (6%). The frequency of P. aeruginosa resistance to gentamicin, ceftizoxime, carbenicillin, cephalothin and ceftazidime was over 90%. The antibiotics to which P. aeruginosa was most sensitive were amikacin and tetracyclin. The "O" serotypes isolated from the 117 Pseudomona aeroginosa isolates were serotypes O:2, O:5, O:6, O:8, O:11, O:12 and O:16. The most common serotype was O:6 (20/17%) followed by O:11 (18/15%) and O:5 (14/12%). The serotype most resistant was O:16 (8%) and the most sensitive was O:8 (2%). Since treatment of infection with available antibiotics according to the results attained proved to be difficult, prevention of infection in the burned patients is considered as an appropriate means of conquering overcoming infection problems. The sum of frequencies of serotypes O:6, O:11, O:5 and O:16 was more than 60%, therefore vaccination of burn patients with polyvalent antiserum to these serotypes could possibly produce immunity in more than half of the burned patients. PMID:12052372

  3. 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...

  4. 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...

  5. The sigma factor sigma s affects antibiotic production and biological control activity of Pseudomonas fluorescens Pf-5.

    Science.gov (United States)

    Sarniguet, A; Kraus, J; Henkels, M D; Muehlchen, A M; Loper, J E

    1995-12-19

    Pseudomonas fluorescens Pf-5, a rhizosphere-inhabiting bacterium that suppresses several soilborne pathogens of plants, produces the antibiotics pyrrolnitrin, pyoluteorin, and 2,4-diacetylphloroglucinol. A gene necessary for pyrrolnitrin production by Pf-5 was identified as rpoS, which encodes the stationary-phase sigma factor sigma s. Several pleiotropic effects of an rpoS mutation in Escherichia coli also were observed in an RpoS- mutant of Pf-5. These included sensitivities of stationary-phase cells to stresses imposed by hydrogen peroxide or high salt concentration. A plasmid containing the cloned wild-type rpoS gene restored pyrrolnitrin production and stress tolerance to the RpoS- mutant of Pf-5. The RpoS- mutant overproduced pyoluteorin and 2,4-diacetyl-phloroglucinol, two antibiotics that inhibit growth of the phytopathogenic fungus Pythium ultimum, and was superior to the wild type in suppression of seedling damping-off of cucumber caused by Pythium ultimum. When inoculated onto cucumber seed at high cell densities, the RpoS- mutant did not survive as well as the wild-type strain on surfaces of developing seedlings. Other stationary-phase-specific phenotypes of Pf-5, such as the production of cyanide and extracellular protease(s) were expressed by the RpoS- mutant, suggesting that sigma s is only one of the sigma factors required for the transcription of genes in stationary-phase cells of P. fluorescens. These results indicate that a sigma factor encoded by rpoS influences antibiotic production, biological control activity, and survival of P. fluorescens on plant surfaces. PMID:8618880

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Isolation and identification of N-mercapto-4-formylcarbostyril, an antibiotic produced by Pseudomonas fluorescens.

    Science.gov (United States)

    Fakhouri, W; Walker, F; Vogler, B; Armbruster, W; Buchenauer, H

    2001-12-01

    Pseudomonas fluorescens strain G308 isolated from barley leaves produces a novel antibiotic substance that was purified by preparative TLC and HPLC and identified as N-mercapto-4-formylcarbostyril (Cbs) by LC/DAD, IR, LC-ES(+)/MS, LC-ES(-)/MS, GC-EI/MS, LC-HRES(+)/MS, mass isotope ratios analysis, 1H NMR and 13C NMR analysis. The purified new antibiotic compound is effective against many phytopathogenic fungi in vitro. The compound inhibited at 25 ppm spore germination and germ tube growth of the following fungi; Fusarium oxysporum f. sp. lycopersici, Fusarium culmorum, Cladosporium cucumerinum and Colletotrichum lagenarium. At concentrations up to 125 ppm, the compound did not interfere with release of zoospores from sporangia and germination of encysted zoospores of Phytophthora infestans. PMID:11738425

  8. Antibiotic and Biosurfactant Properties of Cyclic Lipopeptides Produced by Fluorescent Pseudomonas spp. from the Sugar Beet Rhizosphere

    OpenAIRE

    Nielsen, T H; Sørensen, D.; Tobiasen, C.; Andersen, J B; Christophersen, C.; Givskov, M.; Sørensen, J.

    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...

  9. The Mechanism of Resistance of Pseudomonas Aeruginosa to β-lactam Antibiotics and Clinical Significance

    Institute of Scientific and Technical Information of China (English)

    宋建新; 阮秋蓉; 齐俊英; 高美英; 王以光

    2002-01-01

    Summary: To study the resistant mechanism and clinical significance of pseudomonas aeruginosato β-lactam antibiotics, the outer membrane permeability rate of 30 P. aeruginosa strains to 5 β-lactam antibiotics was measured and their production of β-lactamase and the β-lactamase genes theycarried detected. Furthermore, the relationship between the permeability, β-lactamase and theclinical effects of β-lactam antibiotics was observed. By using 14C-penicillin and liquid-scintillantisotope assay, the affinity of penicillin binding proteins (PBPs) was measured and their roles inthe resistant mechanism studied. It was revealed that the permeability rate was higher in sensitivestrains than in resistant ones (P<0. 05). All strains harbored 1-4 β-lactamase genes and producedβ-lactamase. Higher permeability rate and higher degree of stability to β-lactamase indicated betterclinical therapeutic effects. The affinity of PBPs changed little without regard to the permeabilityand β-lactamase. These results suggested that the permeability of outer membrane and β-lacta-mase, but not PBPs, played important roles in the resistant mechanism of P. aeruginosa to β-lac-tam antibiotics and affected the clinical therapeutic effectiveness of some patients.

  10. Antibiotic Resistance Pattern in Pseudomonas Aeruginosa Species Isolated at a Tertiary Care Hospital, Ahmadabad

    Directory of Open Access Journals (Sweden)

    Rajat Rakesh M

    2012-04-01

    Full Text Available Introduction: Pseudomonas aeruginosa (Ps.aeruginosa is one of the important bacterial pathogens isolated from various samples. Despite advances in medical and surgical care and introduction of wide variety of antimicrobial agents against having anti-pseudomonal activities, life threatening infection caused by Ps. aeruginosa continues to cause complications in hospital acquired infections. Several different epidemiological studies indicate that antibiotic resistance is increasing in clinical isolates. Material and Method: This study was conducted during April 2009 to april 2010. During this period total of 630 samples were tested, in which 321 samples showed growth of bacteria. Out of 321 samples, 100 clinical isolates of Pseudomonas aeruginosa were isolated. The samples were selected on the basis of their growth on routine MacConkey medium which showed lactose Non-fermenting pale colonies which were oxidase test positive and on Nutrient agar pigmented and non-pigmented colonies with oxidase positive. Antimicrobial susceptibility of all the isolates was performed by the disc-diffusion (Modified-Kirby Baur disc diffusion method according to CLSIs guidelines. Result: In present study, maximum isolates of Ps. aeruginosa isolated from various samples are resistant to tobramycin (68% followed by gentamycin (63%, piperacillin (50%, ciprofloxacin (49% and ceftazidime (43%. Conclusion: To prevent the spread of the resistant bacteria, it is critically important to have strict antibiotic policies while surveillance programmes for multidrug resistant organisms and infection control procedures need to be implemented. [National J of Med Res 2012; 2(2.000: 156-159

  11. 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

    efficient dosing regimen and to minimize the development of antimicrobial tolerance and resistance in biofilm infections. Unfortunately, most previous PK/PD studies of antibiotics have been done on planktonic cells, and extrapolation of the results on biofilms is problematic as bacterial biofilms differ...... from planktonic grown cells in the growth rate, gene expression, and metabolism. Here, we set up several protocols for the studies of PK/PD of antibiotics in biofilm infections of P. aeruginosa in vitro and in vivo. It should be underlined that none of the protocols in biofilms have yet been......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...

  12. 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...

  13. Class 1 integron and Imipenem Resistance in Clinical Isolates of Pseudomonas aeruginosa: Prevalence and Antibiotic Susceptibility

    Directory of Open Access Journals (Sweden)

    M Milani

    2010-12-01

    Full Text Available Background and Objectives: Pseudomonas aeruginosa is one of the most important causative agents of nosocomial infections especially in ICU and burn units. P. aeruginosa infections are normally difficult to eradicate due to acquired resistance to many antibiotics. Recent appearance of carbapenem resistant P. aeruginosa isolates is considered a major healthcare problem. The present study was conducted to detect class 1 integron and antibiotic susceptibility profiles of imipenem-sensitive and resistant clinical isolates of P. aeruginosa."nMaterials and Methods: Antibiotic susceptibility profiles and minimum inhibitory concentration against imipenem was studied in 160 clinical isolates of P. aeruginosa by disk agar diffusion method and Etest, respectively. Detection of class 1 integron was performed by the PCR method. Demographic and microbiological data were compared between imipenem susceptible and non-susceptible isolates by the SPSS software."nResults: PCR results showed that 90 (56.3% of P. aeruginosa isolates carried class 1 integron. Antibiotic susceptibility results revealed that 93 (58.1% were susceptible and 67 (41.9% were non-susceptible to imipenem. Comparison of antibiotic susceptibility patterns showed high level of drug resistance among imipenem non-susceptible isolates. We found that MDR phenotype, presence of class 1 integron and hospitalization in ICU and burn units were significantly associated with imipenem non-susceptible isolates."nConclusion: The high frequency of imipenem resistance was seen among our P. aeruginosa isolates. Since carbapenems are considered as the last drugs used for treatment of P. aeruginosa infections, it is crucial to screen imipenem non-susceptible isolates in infection control and optimal therapy.

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

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, Peter Østrup; Burmølle, Mette; Hentzer, Morten; Haagensen, Janus Anders Juul; Hougen, Hans Petter; Calum, Henrik; Madsen, Kit G; Moser, Claus; Molin, Søren; Høiby, Niels; Givskov, Michael Christian

    The opportunistic human pathogen Pseudomonas aeruginosa is the predominant micro-organism of chronic lung infections in cystic fibrosis (CF) patients. P. aeruginosa colonizes the CF lungs by forming biofilm structures in the alveoli. In the biofilm mode of growth the bacteria are highly tolerant to...

  15. Genome Sequence of Pseudomonas putida Idaho, a Unique Organic-Solvent-Tolerant Bacterium

    OpenAIRE

    Tao, Fei; Tang, Hongzhi; Gai, Zhonghui; Su, Fei; Wang, Xiaoyu; He, Xiaofei; Xu, Ping

    2011-01-01

    Pseudomonas putida Idaho is an organic-solvent-tolerant strain which can degrade and adapt to high concentrations of organic solvents. Here, we announce its first draft genome sequence (6,363,067 bp). We annotated 192 coding sequences (CDSs) responsible for aromatic compound metabolism, 40 CDSs encoding phospholipid synthesis, and 212 CDSs related to stress response.

  16. 76 FR 52871 - Pseudomonas fluorescens Strain CL145A; Exemption From the Requirement of a Tolerance

    Science.gov (United States)

    2011-08-24

    ... Federal Register of September 16, 1992 (57 FR 42700) (FRL-4161-1); and 3. Pseudomonas fluorescens EG-1053...) 305-5805. II. Background and Statutory Findings In the Federal Register of March 16, 2009 (74 FR 11100... tolerance (40 CFR 180.1129) in the Federal Register of August 24, 1994 (59 FR 43490) (FRL-4899-5);...

  17. 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.

  18. Tracking Down Antibiotic-Resistant Pseudomonas aeruginosa Isolates in a Wastewater Network

    Science.gov (United States)

    Slekovec, Céline; Plantin, Julie; Cholley, Pascal; Thouverez, Michelle; Talon, Daniel; Bertrand, Xavier; Hocquet, Didier

    2012-01-01

    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 (≥3×106 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. PMID:23284623

  19. Antibiotic resistance profiles and quorum sensing-dependent virulence factors in clinical isolates of pseudomonas aeruginosa.

    Science.gov (United States)

    Wang, Huafu; Tu, Faping; Gui, Zhihong; Lu, Xianghong; Chu, Weihua

    2013-06-01

    Pseudomonas aeruginosa produces multiple virulence factors that have been associated with quorum sensing. The aim of this study was to evaluate the prevalence of drug resistant profiles and quorum sensing related virulence factors. Pseudomonas aeruginosa were collected from different patients hospitalized in China, the isolates were tested for their susceptibility to different common antimicrobial drugs and detected QS-related virulence factors. We identified 170 isolates displaying impaired phenotypic activity, approximately 80 % of the isolates were found to exhibit the QS-dependent phenotypes, among them, 12 isolates were defective in AHLs production, and therefore considered QS-deficient strains. Resistance was most often observed to Cefazolin (81.2 %), followed by trimethoprim-sulfamethoxazole (73.5 %), ceftriaxone (62.4 %) and Cefotaxime, Levofloxacin, Ciprofloxacin (58.8 %), and to a lesser extent Meropenem (20.0 %), Cefepime (18.8 %), and Cefoperazone/sulbactam (2.4 %) The QS-deficient isolates that were negative for virulence factor production were generally less susceptible to the antimicrobials. The results showed a high incidences of antibiotic resistance and virulence properties in P. aeruginosa, and indicate that the clinical use of QS-inhibitory drugs that appear superior to conventional antimicrobials by not exerting any selective pressure on resistant strains. PMID:24426103

  20. In vitro Evaluation of Antibacterial Efficacy of Natural Honeys in Comparison with Antibiotics on Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Vahid Yavarpour

    2014-06-01

    Full Text Available Background and Aim: Several studies have been done that showed honey has been therapeutic effects on infection disease like Pseudomonas infections. Our aim of this study is evaluation of the antibacterial activity of mono floral and multi floral honeys from different origin of Iran on growth of Pseudomonas aeruginosa and compare their activities with artificial honey and antibiotics. Materials and Methods: Antimicrobial effect of honey was determined by disc diffusion and broth dilution method on 5 different concentration of honey. Results: The highest inhibition zone (16 ± 1/52 mm was recorded from persimmon honey in disc diffusion method. In this study، the minimum inhibitory concentration (MIC for manna honey and other natural honeys obtained 25% and 12.5% respectively. While P. aeruginosa was inhibited at concentration of 50% (ml/ml of artificial honey. Conclusions: This study showed that honey has a significant antibacterial effect on P. aeruginosa. There is a direct link between the concentration of honey and inhibition zone.

  1. Antibiotic resistance profiles of Pseudomonas aeruginosa strains isolated from patients with acute exacerbation of chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Nagihan Demir

    2014-12-01

    For typing and antibiotic susceptibility of isolates the Phoenix bacterial identification system (Becton Dickinson, USA was used.[¤]RESULTS[|]The antibiotic resistance rates of P. aeruginosa were 42.3% for cefepime, 41% for levofloxacin, 38.7% for ciprofloxacin, 29.4% for ceftazidime, 21.7% for cefoperazone / sulbactam, 17.9% for gentamicin, 17.9% for piperacillin / tazobactam, 8.9% for imipenem, 5.1% for amikacin and 2.5% for meropenem. Twenty eight (35.9% of the isolates were found to be sensitive to all of these antibiotics. Forty six (58.9% of the patients had steroid and 56 (71.8% of the patients had broad-spectrum antibiotic use.[¤]CONCLUSION[|]In acute exacerbations of chronic obstructive pulmonary disease, the inspection of antibiotic susceptibility of Pseudomonas infection would be beneficial for patient's health and the country's economy.[¤

  2. Deficient autolytic enzyme activity in antibiotic-tolerant lactobacilli.

    OpenAIRE

    Kim, K. S.; Morrison, J O; Bayer, A S

    1982-01-01

    To define the mechanism(s) of penicillin tolerance in lactobacilli, one nontolerant and two tolerant strains were examined for autolytic enzyme activity. When incubated with 14C-labeled cell wall preparations, autolysin extracts of tolerant lactobacilli released significantly less radioactivity than did extracts of nontolerant lactobacilli (p less than 0.02). These differences in the release of radioactivity by nontolerant and tolerant strains were maximal during the logarithmic growth phase....

  3. 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.

  4. ANTIBACTERIAL ACTIVITY OF TRADITIONAL HERBS AND STANDARD ANTIBIOTICS AGAINST POULTRY ASSOCIATED PSEUDOMONAS AERUGINOSA

    Directory of Open Access Journals (Sweden)

    Affia Rafique

    2012-10-01

    Full Text Available Present study aims to access the antibacterial activity of medicinal plants and antibiotics against poultry associated Pseudomonas aeruginosa. P. aeruginosa is the most widespread avian pathogen and it produces a range of toxins and enzymes that may contribute to pathogenicity. P. aeruginosa was isolated from the chicken liver and identified through biochemical methods. The antibacterial activity of extracts of medicinal herbs and various antibiotics were analyzed against P. aeruginosa through agar disc diffusion method. P. aeruginosa was susceptible against Norfloxacin, Chloramphenicol, Streptomycin, Gentamicin, Tobramycin, and Ciprofloxacin. Whereas, moderately susceptible in case of Oxytetracycline, Neomycin, Lincomycin, and Sulfomethoxyzol. It was also analyzed that Ampicillin, Tetracycline, Penicillin G and Trimethoprim had no effect. Among the plants tested C. zylanicum, C. cyminum, T. ammi, S. aromaticum and green part of M. charantia were most active. The maximum antibacterial activity was calculated by the extracts of isoamylalcohol of C. zylanicum, C. cyminum, T. ammi, S. aromaticum, and ethanolic and methanol extract of green part of M. charantia against P. aeruginosa. This study indicated that these medicinal plants could be the potential source for antimicrobial agents. Hence, these medicinal plants can be further subjected to isolation of the therapeutic antimicrobials and further pharmacological evaluation.

  5. The transcriptional regulator CzcR modulates antibiotic resistance and quorum sensing in Pseudomonas aeruginosa.

    Science.gov (United States)

    Dieppois, Guennaëlle; Ducret, Véréna; Caille, Olivier; Perron, Karl

    2012-01-01

    The opportunistic pathogen Pseudomonas aeruginosa responds to zinc, cadmium and cobalt by way of the CzcRS two-component system. In presence of these metals the regulatory protein CzcR induces the expression of the CzcCBA efflux pump, expelling and thereby inducing resistance to Zn, Cd and Co. Importantly, CzcR co-regulates carbapenem antibiotic resistance by repressing the expression of the OprD porin, the route of entry for these antibiotics. This unexpected co-regulation led us to address the role of CzcR in other cellular processes unrelated to the metal response. We found that CzcR affected the expression of numerous genes directly involved in the virulence of P. aeruginosa even in the absence of the inducible metals. Notably the full expression of quorum sensing 3-oxo-C12-HSL and C4-HSL autoinducer molecules is impaired in the absence of CzcR. In agreement with this, the virulence of the czcRS deletion mutant is affected in a C. elegans animal killing assay. Additionally, chromosome immunoprecipitation experiments allowed us to localize CzcR on the promoter of several regulated genes, suggesting a direct control of target genes such as oprD, phzA1 and lasI. All together our data identify CzcR as a novel regulator involved in the control of several key genes for P. aeruginosa virulence processes. PMID:22666466

  6. The transcriptional regulator CzcR modulates antibiotic resistance and quorum sensing in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Guennaëlle Dieppois

    Full Text Available The opportunistic pathogen Pseudomonas aeruginosa responds to zinc, cadmium and cobalt by way of the CzcRS two-component system. In presence of these metals the regulatory protein CzcR induces the expression of the CzcCBA efflux pump, expelling and thereby inducing resistance to Zn, Cd and Co. Importantly, CzcR co-regulates carbapenem antibiotic resistance by repressing the expression of the OprD porin, the route of entry for these antibiotics. This unexpected co-regulation led us to address the role of CzcR in other cellular processes unrelated to the metal response. We found that CzcR affected the expression of numerous genes directly involved in the virulence of P. aeruginosa even in the absence of the inducible metals. Notably the full expression of quorum sensing 3-oxo-C12-HSL and C4-HSL autoinducer molecules is impaired in the absence of CzcR. In agreement with this, the virulence of the czcRS deletion mutant is affected in a C. elegans animal killing assay. Additionally, chromosome immunoprecipitation experiments allowed us to localize CzcR on the promoter of several regulated genes, suggesting a direct control of target genes such as oprD, phzA1 and lasI. All together our data identify CzcR as a novel regulator involved in the control of several key genes for P. aeruginosa virulence processes.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    OpenAIRE

    Maqshoof Ahmad; Zahir, Zahir A.; Farheen Nazli; Fareeha Akram; Muhammad Arshad; Muhammad Khalid

    2013-01-01

    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 contain...

  9. 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.

  10. 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

    some also had antibiotic properties towards root-pathogenic microfungi. The CLP-producing P. fluorescens strains provide a useful resource for selection of biological control agents, whether a single strain or a consortium of strains was used to maximize the synergistic effect of multiple antagonistic......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...

  11. Selective target inactivation rather than global metabolic dormancy causes antibiotic tolerance in uropathogens.

    Science.gov (United States)

    Goneau, Lee W; Yeoh, Nigel S; MacDonald, Kyle W; Cadieux, Peter A; Burton, Jeremy P; Razvi, Hassan; Reid, Gregor

    2014-01-01

    Persister cells represent a multidrug-tolerant (MDT), physiologically distinct subpopulation of bacteria. The ability of these organisms to survive lethal antibiotic doses raises concern over their potential role in chronic disease, such as recurrent urinary tract infection (RUTI). Persistence is believed to be conveyed through global metabolic dormancy, which yields organisms unresponsive to external stimuli. However, recent studies have contested this stance. Here, various antibiotics that target different cellular processes were used to dissect the activity of transcription, translation, and peptidoglycan turnover in persister cells. Differential susceptibility patterns were found in type I and type II persisters, and responses differed between Staphylococcus saprophyticus and Escherichia coli uropathogens. Further, SOS-deficient strains were sensitized to ciprofloxacin, suggesting DNA gyrase activity in persisters and indicating the importance of active DNA repair systems for ciprofloxacin tolerance. These results indicate that global dormancy per se cannot sufficiently account for antibiotic tolerance. Rather, the activity of individual cellular processes dictates multidrug tolerance in an antibiotic-specific fashion. Furthermore, the susceptibility patterns of persisters depended on their mechanisms of onset, with subinhibitory antibiotic pretreatments selectively shutting down cognate targets and increasing the persister fraction against the same agent. Interestingly, antibiotics targeting transcription and translation enhanced persistence against multiple agents indirectly related to these processes. Conducting these assays with uropathogenic E. coli isolated from RUTI patients revealed an enriched persister fraction compared to organisms cleared with standard antibiotic therapy. This finding suggests that persister traits are either selected for during prolonged antibiotic treatment or initially contribute to therapy failure. PMID:24449771

  12. Commensal Pseudomonas Species Isolated from Wastewater and Freshwater Milieus in the Eastern Cape Province, South Africa, as Reservoir of Antibiotic Resistant Determinants

    OpenAIRE

    Okoh, Anthony I.; Mvuyo Tom; Anibal Sosa; Igbinosa, Isoken H.; Nwodo, Uchechukwu U.

    2012-01-01

    Pseudomonas species are opportunistic pathogens with implications in a wide range of diseases including cystic fibrosis and sickle cell anaemia. Because of their status as multidrug resistant (MDR) and extremely drug resistant (XDR) bacteria Pseudomonas species represent a threat to public health. Prevalence, antibiogram and associated antibiotic resistant genes of Pseudomonas species isolated from freshwater and mixed liquor envi...

  13. Complex marine natural products as potential epigenetic and production regulators of antibiotics from a marine Pseudomonas aeruginosa

    Science.gov (United States)

    Wang, Bin; Waters, Amanda L.; Sims, James W.; Fullmer, Alexis; Ellison, Serena; Hamann, Mark T.

    2013-01-01

    Marine microbes are capable of producing secondary metabolites for defense and competition. Factors exerting an impact on secondary metabolite production of microbial communities included bioactive natural products and co-culturing. These external influences may have practical applications such as increased yields or the generation of new metabolites from otherwise silent genes in addition to reducing or limiting the production of undesirable metabolites. In this paper, we discuss the metabolic profiles of a marine Pseudomonas aeruginosa in the presence of a number of potential chemical epigenetic regulators, adjusting carbon sources and co-culturing with other microbes to induce a competitive response. As a result of these stressors certain groups of antibiotics or antimalarial agents were increased most notably when treating P. aeruginosa with sceptrin and co-culturing with another Pseudomonas sp. An interesting cross-talking event between these two Pseudomonas species when cultured together and exposed to sceptrin was observed. PMID:23563743

  14. The sigma factor sigma s affects antibiotic production and biological control activity of Pseudomonas fluorescens Pf-5.

    OpenAIRE

    Sarniguet, A.; Kraus, J.; Henkels, M D; Muehlchen, A M; Loper, J E

    1995-01-01

    Pseudomonas fluorescens Pf-5, a rhizosphere-inhabiting bacterium that suppresses several soilborne pathogens of plants, produces the antibiotics pyrrolnitrin, pyoluteorin, and 2,4-diacetylphloroglucinol. A gene necessary for pyrrolnitrin production by Pf-5 was identified as rpoS, which encodes the stationary-phase sigma factor sigma s. Several pleiotropic effects of an rpoS mutation in Escherichia coli also were observed in an RpoS- mutant of Pf-5. These included sensitivities of stationary-p...

  15. 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.

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

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    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.

  17. Effects of Pseudomonas contamination or antibiotic decontamination of the GI tract on acute radiation lethality

    International Nuclear Information System (INIS)

    The influence of antibiotic decontamination or Psuedomonas contamination of the GI tract prior to whole-body neutron or gamma irradiation was studied. For neutron doses greater than 6.7 Gy and gamma ray doses greater than 14.4 Gy, the median survival time of SPF rats was relatively constant at 4.4 days, indicating death was due to intestinal injury. Within the dose range of 4.9 to 6.7 Gy of neutrons or 9.6 to 14.4 Gy of photons, median survival time was inversely related to dose and varied from 12 to 4.6 days. Decontamination or Pseudomonas contamination of the GI tract increased or decreased, respectively, median survival time 1 to 5 days in this survival dose dependent range. The effects of these treatments, however, were negligible in the range of doses in which median survival time was dose independent. These treatments had little effect on the ultimate survival after irradiation as measured by either the LD50/5 day or LD50/30 day endpoints

  18. Effect of retS gene on antibiotics production in Pseudomonas fluorescens FD6.

    Science.gov (United States)

    Zhang, Qingxia; Xiao, Qi; Xu, Jingyou; Tong, Yunhui; Wen, Jia; Chen, Xijun; Wei, Lihui

    2015-11-01

    A hybrid sensor kinase termed RetS (regulator of exopolysaccharide and Type III secretion) controls expression of numerous genes in Pseudomonas aeruginosa. To investigate the function of RetS in P. fluorescens FD6, the retS gene was disrupted. Genetic inactivation of retS resulted in enhanced production of 2, 4-diacetylphloroglucinol, pyrrolnitrin, and pyoluteorin. The retS mutant also exhibited significant increase in phlA-lacZ, prnA-lacZ, and pltA-lacZ transcription levels, influencing expression levels of the small regulatory RNAs RsmX and RsmZ. In the gacSretS double mutant, all the phenotypic changes caused by the retS deletion were reversed to the level of gacS single mutant. Furthermore, the retS mutation drastically elevated biofilm formation and improved the colonization ability of strain FD6 on wheat rhizospheres. Based on these results, we proposed that RetS negatively controlled the production of antibiotics through the Gac/Rsm pathway in P. fluorescens FD6. PMID:26505308

  19. Saccharomyces cerevisiae genome-wide mutant screen for sensitivity to 2,4-diacetylphloroglucinol, a biocontrol antibiotic produced by Pseudomonas fluorescens

    Science.gov (United States)

    2,4-diacetylphloroglucinol (2,4-DAPG) is an antibiotic produced by Pseudomonas fluorescens that plays a key role in the ability of the bacterium to suppress phytopathogenic fungi. 2,4-DAPG has broad antibiotic activity, affecting organisms ranging from bacteria to higher plants. The biosynthesis and...

  20. 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.

  1. Dynamics of Mutator and Antibiotic-Resistant Populations in a Pharmacokinetic/Pharmacodynamic Model of Pseudomonas aeruginosa Biofilm Treatment

    DEFF Research Database (Denmark)

    Macià, María D.; Pérez, José L.; Molin, Søren;

    2011-01-01

    Biofilm growth, antibiotic resistance, and mutator phenotypes are key components of chronic respiratory infections by Pseudomonas aeruginosa in cystic fibrosis patients. We examined the dynamics of mutator and antibiotic-resistant populations in P. aeruginosa flow-cell biofilms, using fluorescently...... monitored by confocal laser scanning microscopy (CLSM), and the numbers of viable cells and resistant mutants (4- and 16-fold MICs) were determined. Despite optimized pharmacokinetic/pharmacodynamic (PK/PD) parameters, CIP treatment did not suppress resistance development in P. aeruginosa biofilms. One.......01 proportion, took over the whole biofilm after only 2 days of CIP treatment outnumbering PAO1 by 3 log at t4. Our results show that mutational mechanisms play a major role in biofilm antibiotic resistance and that theoretically optimized PK/PD parameters fail to suppress resistance development, suggesting...

  2. 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

    At the Danish CF Center patients with chronic Pseudomonas aeruginosa lung infection were treated 3-4 times a year (from 1976) with a 2-week intravenous antipseudomonal course which included preferentially an aminoglycoside and a beta-lactam antibiotic. We investigated the development of antibiotic...... 1991 (100 strains). All the strains were screened and assayed semiquantitatively for beta-lactamase activity by use of nitrocefin. We found a significant (p < 0.005) increase in the MIC values of the P. aeruginosa strains against piperacillin and ceftazidime. However, no significant correlation 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...

  3. 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)

    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

  4. Low Concentrations of Nitric Oxide Modulate Streptococcus pneumoniae Biofilm Metabolism and Antibiotic Tolerance.

    Science.gov (United States)

    Allan, Raymond N; Morgan, Samantha; Brito-Mutunayagam, Sanjita; Skipp, Paul; Feelisch, Martin; Hayes, Stephen M; Hellier, William; Clarke, Stuart C; Stoodley, Paul; Burgess, Andrea; Ismail-Koch, Hasnaa; Salib, Rami J; Webb, Jeremy S; Faust, Saul N; Hall-Stoodley, Luanne

    2016-04-01

    Streptococcus pneumoniaeis one of the key pathogens responsible for otitis media (OM), the most common infection in children and the largest cause of childhood antibiotic prescription. Novel therapeutic strategies that reduce the overall antibiotic consumption due to OM are required because, although widespread pneumococcal conjugate immunization has controlled invasive pneumococcal disease, overall OM incidence has not decreased. Biofilm formation represents an important phenotype contributing to the antibiotic tolerance and persistence ofS. pneumoniaein chronic or recurrent OM. We investigated the treatment of pneumococcal biofilms with nitric oxide (NO), an endogenous signaling molecule and therapeutic agent that has been demonstrated to trigger biofilm dispersal in other bacterial species. We hypothesized that addition of low concentrations of NO to pneumococcal biofilms would improve antibiotic efficacy and that higher concentrations exert direct antibacterial effects. Unlike in many other bacterial species, low concentrations of NO did not result inS. pneumoniaebiofilm dispersal. Instead, treatment of bothin vitrobiofilms andex vivoadenoid tissue samples (a reservoir forS. pneumoniaebiofilms) with low concentrations of NO enhanced pneumococcal killing when combined with amoxicillin-clavulanic acid, an antibiotic commonly used to treat chronic OM. Quantitative proteomic analysis using iTRAQ (isobaric tag for relative and absolute quantitation) identified 13 proteins that were differentially expressed following low-concentration NO treatment, 85% of which function in metabolism or translation. Treatment with low-concentration NO, therefore, appears to modulate pneumococcal metabolism and may represent a novel therapeutic approach to reduce antibiotic tolerance in pneumococcal biofilms. PMID:26856845

  5. 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

    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......] strains). As colistin-induced vancomycin tolerance is reversible, it may not be detected by routine sensitivity testing and may be responsible for treatment failure at vancomycin doses expected to be clinically effective based on such routine testing. IMPORTANCE: Commonly, antibiotic resistance is...

  6. Retrospective analysis of antibiotic susceptibility patterns of respiratory isolates of Pseudomonas aeruginosa in a Turkish University Hospital

    Directory of Open Access Journals (Sweden)

    Akkurt Ibrahim

    2003-03-01

    Full Text Available Abstract Background Lower respiratory tract infections due to Pseudomonas aeruginosa have a high mortality rate. Antibacterial activity of various antibiotics against P. aeruginosa isolated from each hospital depends on the variety or amount of antibiotics used in each hospital. Method A total of 249 respiratory isolates of Pseudomonas aeruginosa in Sivas (Turkey were included between January-1999 and January-2002. Isolates were tested against 14 different antibiotics by a disc diffusion method or standardized microdilution technique. Results Organisms were cultured from the following specimens: sputum (31.3%, transtracheal/endotracheal aspirates (37.8%, and bronchial lavage (30.9%. Isolates in bronchial lavage were highly susceptible to cefoperazone and aminoglycosides. Resistance to ampicillin/sulbactam was 98.8%, ticarcillin 40.1%, ticarcillin/clavulanic acid 11.2%, piperacillin 21.8%, aztreonam 66.6%, cefotaxim 75.4%, ceftriaxone 84.2%, cefoperazone 39.0%, ceftazidime 50.8%, gentamicin 57.5%, tobramycin 58.4%, amikacin 25.4%, ciprofloxacin 16.1%, and imipenem/cilastatin 21.6%. The term multidrug-resistant P. aeruginosa covered resistance to imipenem, ciprofloxacin, ceftazidime, gentamicin, and piperacillin. 1.2% of isolates were multidrug-resistant. Conclusions These findings suggest that amikacin resistance increases progressively in Turkey. Piperacillin and ticarcillin/clavulanate were the most active agents against both imipenem- and ciprofloxacin-resistant isolates in our region.

  7. 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. PMID:26187825

  8. Biosynthetic Origin of the Antibiotic Pseudopyronines A and B in Pseudomonas putida BW11M1.

    Science.gov (United States)

    Bauer, Judith S; Ghequire, Maarten G K; Nett, Markus; Josten, Michaele; Sahl, Hans-Georg; De Mot, René; Gross, Harald

    2015-11-01

    Within the framework of our effort to discover new antibiotics from pseudomonads, pseudopyronines A and B were isolated from the plant-derived Pseudomonas putida BW11M1. Pseudopyronines are 3,6-dialkyl-4-hydroxy-2-pyrones and displayed high in vitro activities against several human pathogens, and in our hands also towards the plant pathogen Pseudomonas savastanoi. Here, the biosynthesis of pseudopyronine B was studied by a combination of feeding experiments with isotopically labeled precursors, genomic sequence analysis, and gene deletion experiments. The studies resulted in the deduction of all acetate units and revealed that the biosynthesis of these α-pyrones occurs with a single PpyS-homologous ketosynthase. It fuses, with some substrate flexibility, a 3-oxo-fatty acid and a further unbranched saturated fatty acid, both of medium chain-length and provided by primary metabolism. PMID:26507104

  9. Antibiotics.

    Science.gov (United States)

    Hariprasad, Seenu M; Mieler, William F

    2016-01-01

    The Endophthalmitis Vitrectomy Study (EVS) provided ophthalmologists with evidence-based management strategies to deal with endophthalmitis for the first time. However, since the completion of the EVS, numerous unresolved issues remain. The use of oral antibiotics has important implications for the ophthalmologist, particularly in the prophylaxis and/or management of postoperative, posttraumatic, or bleb-associated bacterial endophthalmitis. One can reasonably conclude that significant intraocular penetration of an antibiotic after oral administration may be a property unique to the newer-generation fluoroquinolones. Prophylactic use of mupirocin nasal ointment resulted in significant reduction of conjunctival flora with or without preoperative topical 5% povidone-iodine preparation. Ocular fungal infections have traditionally been very difficult to treat due to limited therapeutic options both systemically and intravitreally. Because of its broad spectrum of coverage, low MIC90 levels for the organisms of concern, good tolerability, and excellent bioavailability, voriconazole through various routes of administration may be useful to the ophthalmologist in the primary treatment of or as an adjunct to the current management of ocular fungal infections. PMID:26501865

  10. Evaluation of an Antibiotic-Producing Strain of Pseudomonas fluorescens for Suppression of Plant-Parasitic Nematodes

    OpenAIRE

    Timper, Patricia; Koné, Daouda; Yin, Jingfang; Ji, Pingsheng; McSpadden Gardener, Brian B.

    2009-01-01

    The antibiotic 2,4-diacetylphloroglucinol (DAPG), produced by some strains of Pseudomonas spp., is involved in suppression of several fungal root pathogens as well as plant-parasitic nematodes. The primary objective of this study was to determine whether Wood1R, a D-genotype strain of DAPG-producing P. fluorescens, suppresses numbers of both sedentary and migratory plant-parasitic nematodes. An experiment was conducted in steam-heated soil and included two seed treatments (with Wood1R and a c...

  11. 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 ...

  12. 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

    , 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......Resistance to beta-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 beta-lactamase and biofilm formation. The purpose of this study was to investigate the...... 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...

  13. 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...

  14. Characterization of paired mucoid/non-mucoid Pseudomonas aeruginosa isolates from Danish cystic fibrosis patients: antibiotic resistance, beta-lactamase activity and RiboPrinting

    DEFF Research Database (Denmark)

    Ciofu, O; Fussing, V; Bagge, N;

    2001-01-01

    The purpose of this study was to characterize 42 paired mucoid and non-mucoid Danish cystic fibrosis (CF) Pseudomonas aeruginosa isolates collected in 1997, by RiboPrinting, antibiotic susceptibility and beta-lactamase activity. Eight P. aeruginosa isolates collected before 1991 were included for...... before 1991 had an antibiotic susceptibility pattern similar to the 1997 isolates. Despite prolonged and intensive antibiotic treatment, susceptible mucoid isolates were isolated from the CF sputum, possibly because these bacteria are protected from the selective pressure of antibiotics by the resistant...

  15. Cyclic Lipodepsipeptides Produced by Pseudomonas spp. Naturally Present in Raw Milk Induce Inhibitory Effects on Microbiological Inhibitor Assays for Antibiotic Residue Screening

    OpenAIRE

    Reybroeck, Wim; De Vleeschouwer, Matthias; Marchand, Sophie; Sinnaeve, Davy; Heylen, Kim; De Block, Jan; Madder, Annemieke; Martins, José; Heyndrickx, Marc

    2014-01-01

    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 degrees 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 hea...

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

    OpenAIRE

    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 test system lies in variation of the measured responses. We tested the variation and the occurrence of cotolerance experimentally, using antibiotics as toxicants, soil microcosms as microbial commu...

  17. Tolerance of Escherichia coli to Fluoroquinolone Antibiotics Depends on Specific Components of the SOS Response Pathway

    OpenAIRE

    Theodore, Alyssa; Lewis, Kim; Vulić, Marin

    2013-01-01

    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 o...

  18. Combined Toxic Effects of Heavy Metals and Antibiotics on a Pseudomonas fluorescens Strain ZY2 Isolated from Swine Wastewater

    Directory of Open Access Journals (Sweden)

    Yan Zhou

    2015-01-01

    Full Text Available A Pseudomonas fluorescens strain ZY2, isolated from swine wastewater, was used to investigate the synergistic effects of five heavy metals (Pb, Cu, Zn, Cr(VI and Hg on bacterial resistance to antibiotics. Results indicate that the combined effects of antibiotic type, heavy metal type and concentration were significant (p < 0.01. Cross-resistance to Hg and antibiotics was the most noticeable. Moreover, the resistance to Hg and cefradine or amoxicillin, and Cr and amoxicillin were synergistic for low heavy metal concentrations, and turned antagonistic with increasing concentrations, while the resistances to Cr or Cu and cefradine, Pb or Cu and amoxicillin, Cu and norfloxacin showed reverse effects. In addition, resistance to Zn and amoxicillin were always synergetic, while resistance to Pb and cefradine or norfloxacin, Cr or Hg and norfloxacin as well as all the heavy metals and tetracycline were antagonistic. These results indicate that bacterial resistance to antibiotics can be affected by the type and concentration of co-exposed heavy metals and may further threaten people’s health and ecological security severely via horizontal gene transfer.

  19. 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.

  20. Metabolite profiling reveals abiotic stress tolerance in Tn5 mutant of Pseudomonas putida.

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    Vasvi Chaudhry

    Full Text Available Pseudomonas is an efficient plant growth-promoting rhizobacteria (PGPR; however, intolerance to drought and high temperature limit its application in agriculture as a bioinoculant. Transposon 5 (Tn5 mutagenesis was used to generate a stress tolerant mutant from a PGPR Pseudomonas putida NBRI1108 isolated from chickpea rhizosphere. A mutant NBRI1108T, selected after screening of nearly 10,000 transconjugants, exhibited significant tolerance towards high temperature and drought. Southern hybridization analysis of EcoRI and XhoI restricted genomic DNA of NBRI1108T confirmed that it had a single Tn5 insertion. The metabolic changes in the polar and non-polar extracts of NBRI1108 and NBRI1108T were examined using 1H, 31P nuclear magnetic resonance (NMR spectroscopy and gas chromatography-mass spectrometry (GC-MS. Thirty six chemically diverse metabolites consisting of amino acids, fatty acids and phospholipids were identified and quantified. Insertion of Tn5 influenced amino acid and phospholipid metabolism and resulted in significantly higher concentration of aspartic acid, glutamic acid, glycinebetaine, glycerophosphatidylcholine (GPC and putrescine in NBRI1108T as compared to that in NBRI1108. The concentration of glutamic acid, glycinebetaine and GPC increased by 34%, 95% and 100%, respectively in the NBRI1108T as compared to that in NBRI1108. High concentration of glycerophosphatidylethanolamine (GPE and undetected GPC in NBRI1108 indicates that biosynthesis of GPE may have taken place via the methylation pathway of phospholipid biosynthesis. However, high GPC and low GPE concentration in NBRI1108T suggest that methylation pathway and phosphatidylcholine synthase (PCS pathway of phospholipid biosynthesis are being followed in the NBRI1108T. Application of multivariate principal component analysis (PCA on the quantified metabolites revealed clear variations in NBRI1108 and NBRI1108T in polar and non-polar metabolites. Identification of abiotic

  1. Antibiotic Resistance Profiles and Quorum Sensing-Dependent Virulence Factors in Clinical Isolates of Pseudomonas Aeruginosa

    OpenAIRE

    Wang, Huafu; Tu, Faping; Gui, Zhihong; Lu, Xianghong; Chu, Weihua

    2013-01-01

    Pseudomonas aeruginosa produces multiple virulence factors that have been associated with quorum sensing. The aim of this study was to evaluate the prevalence of drug resistant profiles and quorum sensing related virulence factors. Pseudomonas aeruginosa were collected from different patients hospitalized in China, the isolates were tested for their susceptibility to different common antimicrobial drugs and detected QS-related virulence factors. We identified 170 isolates displaying impaired ...

  2. Antibiotic Resistance Pattern of Pseudomonas Aeruginosa, Isolated from Patient with Burn Wound Infection in Guilan,Iran

    Directory of Open Access Journals (Sweden)

    Iraj Nikokar

    2013-03-01

    Full Text Available Background and Objectives: Antibiotic resistance of Pseudomonas aeruginosa remains a major problem in burn patients. The main objective of this study was to determine the antibiotic resistance pattern and frequency of class 1 integrons among P. aeruginosa strains isolated from patients with burn wound infections in a new Burn Centre in Guilan, Iran.Materials and Methods: The bacterial isolates were collected from 182 patients with burn wound infections and P. aeruginosa species were identified by standard bacteriological methods. The drug susceptibility test, using 11 antimicrobial agents, was performed for all the isolates via agar disk diffusion method. PCR was carried out for the detection of integrons.Results: Out of a total of 182 hospitalized patients in the burn center assessed, 86 (47% found to have P. aeruginosa in their isolates. Resistance rates to various antibiotics were as follows: cloxacillin (91.8%, cotrimoxazole (86%, cephazolin (83.7%, carbenicillin (74.4%, piperacillin (69.9%, ceftazidime (68.8%, ciprofloxacin (66.3%, tobramycin (58.2%, amikacin (48.8% and gentamicin (37.2%, while the most effective antibiotic was imipenem with a resistance rate of 23.3%. Thirty nine (45.3% isolates were detected as multi-drug resistant. The PCR results showed that 37 (43% P. aeruginosa isolates and 27 (69.2% multi-drug resistant strains harbored class 1 integrons. A significant correlation was obtained between the presence of integrons and resistance against imipenem, ceftazidime, piperacillin and ciprofloxacin (P < 0.001.Conclusion: Optimization of using antimicrobial agents and control of infection is recommended to prevent the increasing population of drug resistant organisms in the new burn centre setting in this study. Furthermore, the high frequency of class 1 integrons among multi-drug resistant strains might be responsible for dissemination of antibiotic resistance gene.

  3. 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 intensive antibiotic treatment of cystic fibrosis (CF) patients with chronic lung infection with Pseudomonas aeruginosa has improved the survival rate and the clinical condition of Danish patients. Acquirement of resistance to anti-pseudomonal antibiotics is one of the main drawbacks of this...... therapeutic strategy and our results showed the development of resistance of P. aeruginosa to several antibiotics during 25 years of intensive antibiotic treatment. Our studies have been concentrating on the development of resistance to beta-lactam antibiotics. We have shown an association between the...... 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...

  4. Antibiotic susceptibility patterns of pseudomonas corneal ulcers in contact lens wearers

    Directory of Open Access Journals (Sweden)

    Mehrdad Mohammadpour

    2011-01-01

    Conclusion : P. aeruginosa was highly sensitive to ceftazidime, ciprofloxacin, and amikacin. All cases were resistant to cefazolin. Resistance to multiple antibiotics might be a significant concern in patients with corneal ulcers. In referral centers dealing with corneal ulcers, the initial antibiotic regimens should be changed from time to time to prevent this phenomenon.

  5. [Mechanism of heavy-metal tolerance in Pseudomonas aeruginosa ZGKD2].

    Science.gov (United States)

    Zhang, Yu-Xiu; Wang, Jiao; Chai, Tuan-Yao; Zhang, Qian; Liu, Jin-Guang; Li, Xia; Bai, Zhi-Qiang; Su, Zeng-Jian

    2012-10-01

    The cadmium-resistant bacterium Pseudomonas aeruginosa strain ZGKD2 exhibiting tolerance to various heavy-metals was isolated from gangue pile of coal area in our laboratory. This bacterium could serve as an effective metal sequestering and growth-promoting bioinoculant for plants grown in metal-contaminated soil. However, the mechanism of heavy-metal tolerance is still unclear. When the beef extract-peptone medium was supplemented with 200-3 000 micromol x L(-1) Cd2+, Cu2+, Zn2+, Ni2+, Pb2+ or Mn2+, the maximum biomass of strain ZGKD2 decreased with the increase of heavy-metal concentrations, while different concentrations of heavy-metals had no significant effect on its alkaline production. Stationary-phase cells of strain ZGKD2 were exposed to 0, 200, 600 and 1 000 micromol x L(-1) of Cd2+ , Cu2+, Zn2+ and Ni2+ or 0, 1 000, 2 000 and 3 000 micromol x L(-1) of Pb2+ and Mn2+ for 2 h, respectively. The activity of SOD and CAT increased in a heavy-metal-concentration-dependent manner, especially in the Cd2+ and Cu2+ treatments. The siderophore production of strain ZGKD2 in modified sugar-aspartic acid medium was enhanced by 200- 1 000 micromol x L(-1) of various heavy-metals. Cd2+ and Zn2+ strongly induced the siderophore production of strain ZGKD2, Ni2+ and Mn2+ had little effect, whereas Cu2+ led to significant inhibition. The siderophore production of strain ZGKD2 was positively related with its metal tolerance. These results indicated that alkaline production, siderophore production, and the increase of antioxidant enzyme activities in strain ZGKD2 might be the main mechanisms of heavy-metal tolerance. PMID:23233996

  6. Multicentric study in five African countries of antibiotic susceptibility for three main pathogens: Streptococcus pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa.

    Science.gov (United States)

    Zerouali, Khalid; Ramdani-Bouguessa, Nadjia; Boye, Cheikh; Hammami, Adnane

    2016-08-01

    Antibiotic resistance is a growing clinical and epidemiological problem. We report on the antibiotic susceptibility of three pathogens isolated from patients in Algeria, Egypt, Morocco, Senegal, and Tunisia during 2010-2011. In total, 218 Streptococcus pneumoniae, 428 Staphylococcus aureus, and 414 Pseudomonas aeruginosa strains were collected. S. pneumoniae resistance was noted against penicillin (30.2%), erythromycin (27.4%), cefpodoxime (19.1%), amoxicillin (12.0%), cefotaxime (7.4%), and levofloxacin (3.2%). All the strains were teicoplanin susceptible. Staphylococcus aureus methicillin resistance differed between countries, from 5.0% in Senegal to 62.7% in Egypt. Levofloxacin resistance was low in all countries, and the highest rate (in Egypt) was still only 13.6% for intermediate and resistant strains combined. Most strains were susceptible to fosfomycin (99.3%) and pristinamycin (94.2%). P. aeruginosa resistance was found against levofloxacin (30.4%), ciprofloxacin (29.9%), tobramycin (19.7%), ceftazidime (19.2%), and imipenem (17.9%), but not colistin. Antibiotic susceptibility varied widely between countries, with resistance typically most prevalent in Egypt. PMID:25363146

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

    Science.gov (United States)

    Ciofu, Oana; Jensen, Tim; Pressler, Tacjana; Johansen, Helle Krogh; Koch, Christian; Høiby, Niels

    1996-01-01

    OBJECTIVE: To assess the efficacy and safety of meropenem, administered on a compassionate basis to 62 cystic fibrosis (CF) patients (age: 24plus minus6 years) with hypersensitivity reactions to beta-lactam antibiotics and/or infection by bacteria resistant to other antibiotics. METHODS: Fifty-seven patients were chronically infected with Pseudomonas aeruginosa and 5 with Burkholderia cepacia. In total, 124 courses (1 to 6/patient) of meropenem, 2 g three times a day by intravenous infusion (10 to 15 min) for 14 days, were administered. RESULTS: During treatment for P. aeruginosa the mean increase 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 complaint. The following side effects were observed: nausea (0.8%), itching (4%), rash (3.2%), drug fever (1.6%). CONCLUSIONS: Meropenem proved to be a valuable drug in the treatment of CF patients with chronic pulmonary infection with multiresistant P. aeruginosa and B. cepacia and with hypersensitivity reactions to other beta-lactam drugs. PMID:11866824

  8. Inconsistency of Synergy Between the β-Lactamase Inhibitor CP-45,899 and β-Lactam Antibiotics Against Multiply Drug-Resistant Enterobacteriaceae and Pseudomonas Species

    OpenAIRE

    Fass, Robert J.

    1981-01-01

    Synergy between CP-45,899 and ampicillin or newer β-lactam antibiotics against multiply drug-resistant Enterobacteriaceae and Pseudomonas species was inconsistent. In contrast, synergy between CP-45,899 and ampicillin against β-lactamase-producing strains of Haemophilus influenzae type b and Bacteroides fragilis was consistent and marked.

  9. Increased bactericidal activity of colistin on Pseudomonas aeruginosa biofilms in anaerobic conditions

    OpenAIRE

    Kolpen, Mette; Appeldorff, Cecilie F.; Brandt, Sarah; Mousavi, Nabi; Kragh, Kasper N.; Aydogan, Sevtap; Uppal, Haleema A.; Bjarnsholt, Thomas; Ciofu, Oana; Høiby, Niels; Jensen, Peter Ø.

    2015-01-01

    Tolerance towards antibiotics of Pseudomonas aeruginosa biofilms is recognized as a major cause of therapeutic failure of chronic lung infection in cystic fibrosis (CF) patients. This lung infection is characterized by antibiotic-tolerant biofilms in mucus with zones of O2 depletion mainly due to polymorphonuclear leukocytic activity. In contrast to the main types of bactericidal antibiotics, it has not been possible to establish an association between the bactericidal effects of colistin and...

  10. 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.

  11. Antibiotic therapy against Pseudomonas aeruginosa in cystic fibrosis : a European consensus

    NARCIS (Netherlands)

    Döring, G; Conway, S P; Heijerman, H G; Hodson, M E; Høiby, N; Smyth, A; Touw, D J

    2000-01-01

    Cystic fibrosis (CF) is the most common lethal hereditary disorder with autosomal recessive heredity in caucasians. The majority of CF patients suffer from chronic respiratory infection with the opportunistic bacterial pathogen Pseudomonas aeruginosa. No consensus among clinicians has been reached s

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

    NARCIS (Netherlands)

    Neut, D; Hendriks, JGE; van Horn, [No Value; van der Mei, HC; Busscher, HJ

    2005-01-01

    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 Pseudomon

  13. Biofilm accumulation model that predicts antibiotic resistance of Pseudomonas aeruginosa biofilms.

    OpenAIRE

    Stewart, P.S.

    1994-01-01

    A computer model of biofilm dynamics was adapted to incorporate the activity of an antimicrobial agent on bacterial biofilm. The model was used to evaluate the plausibility of two mechanisms of biofilm antibiotic resistance by qualitative comparison with data from a well-characterized experimental system (H. Anwar, J. L. Strap, and J. W. Costerton, Antimicrob. Agents Chemother. 36:1208-1214, 1992). The two mechanisms involved either depletion of the antibiotic by reaction with biomass or phys...

  14. Offline Controlling of Pseudomonas aeruginosa Resistant to protein Inhibitor Antibiotics Using Combination of EDTA and Na- citrate or Disinfectant (s)

    Institute of Scientific and Technical Information of China (English)

    Amro Abd Al Fattah Amara; Mohamed Zakaria Hussein

    2006-01-01

    Pseudomonas aeruginosa recognized as opportunistic pathogen causes severe infections for hospitalized patients, survive in and resist many antimicrobial agents like antibiotics and disinfectants. The aim of this study is to evaluate the role of EDTA in improving the sensitivity of resistant P. aeruginosa strains to disinfectants and Na-citrate. The strains used in this study were selected in house from Tanta University hospital, Egypt and tested for the synergistic effect of EDTA with Na-citrate or disinfectant (s). The results showed a significant effect ofEDTA in improving P. aeruginosa sensitivity. In conclusion, we proposed that using EDTA in combination with different sanitization compounds and antimicrobial agentsespecially in hospitals aiming to control the spreading of infections.

  15. Changes in antibiotic usage and susceptibility in nosocomial Enterobacteriaceae and Pseudomonas isolates following the introduction of ertapenem to hospital formulary.

    Science.gov (United States)

    Graber, C J; Hutchings, C; Dong, F; Lee, W; Chung, J K; Tran, T

    2012-01-01

    There is concern that widespread usage of ertapenem may promote cross-resistance to other carbapenems. To analyse the impact that adding ertapenem to our hospital formulary had on usage of other broad-spectrum agents and on susceptibilities of nosocomial Enterobacteriaceae and Pseudomonas isolates, we performed interrupted time-series analyses to determine the change in linear trend in antibiotic usage and change in mean proportion and linear trend of susceptibility pre- (March 2004-June 2005) and post- (July 2005-December 2008) ertapenem introduction. Usage of piperacillin-tazobactam (P=0·0013) and ampicillin-sulbactam (P=0·035) declined post-ertapenem introduction. For Enterobacteriaceae, the mean proportion susceptible to ciprofloxacin (P=0·016) and piperacillin-tazobactam (P=0·038) increased, while the linear trend in susceptibility significantly increased for cefepime (P=0·012) but declined for ceftriaxone (P=0·0032). For Pseudomonas, the mean proportion susceptible to cefepime (P=0·011) and piperacillin-tazobactam (P=0·028) increased, as did the linear trend in susceptibility to ciprofloxacin (P=0·028). Notably, no significant changes in carbapenem susceptibility were observed. PMID:21303590

  16. 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.

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

    OpenAIRE

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

    1995-01-01

    Indwelling device infections are associated with considerable morbidity and extremely high cost. Pseudomonas aeruginosa is the most frequent gram-negative etiologic agent associated with infections of indwelling catheters and foreign body implants. It is generally agreed that eradication of infection in the presence of a foreign body requires removal of the foreign body. Using a combination of ceftazidime and ciprofloxacin, we cured nine of nine patients with P. aeruginosa-infected osteosynth...

  18. 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.

  19. The resistance of pseudomonas aeruginosa strains to fluoroquinolone group of antibiotics

    Directory of Open Access Journals (Sweden)

    Algun U

    2004-01-01

    Full Text Available Fluoroquinolones are antibiotics that are very effective against many gram negative microorganisms, including P. aeruginosa. However, resistance to these antibiotics has been reported in recent years as well. In this study, the sensivity of 136 P. aeruginosa strains, isolated from various clinical materials, to fluoroquinolones has been investigated. The lowest resistance rate was in ciprofloxacin with 12.5%. The resistance rates of the others were as follows: norfloxacin 14.7%, levofloxacin 16.9%, ofloxacin 19.9% and pefloxacin 28.7%. The 88.2% of the resistant strains to all fluoroquinolones were originated from intensive care unit.

  20. Phenotypic and genome-wide analysis of an antibiotic-resistant small colony variant (SCV of Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Qing Wei

    Full Text Available BACKGROUND: Small colony variants (SCVs are slow-growing bacteria, which often show increased resistance to antibiotics and cause latent or recurrent infections. It is therefore important to understand the mechanisms at the basis of this phenotypic switch. METHODOLOGY/PRINCIPAL FINDINGS: One SCV (termed PAO-SCV was isolated, showing high resistance to gentamicin and to the cephalosporine cefotaxime. PAO-SCV was prone to reversion as evidenced by emergence of large colonies with a frequency of 10(-5 on media without antibiotics while it was stably maintained in presence of gentamicin. PAO-SCV showed a delayed growth, defective motility, and strongly reduced levels of the quorum sensing Pseudomonas quinolone signal (PQS. Whole genome expression analysis further suggested a multi-layered antibiotic resistance mechanism, including simultaneous over-expression of two drug efflux pumps (MexAB-OprM, MexXY-OprM, the LPS modification operon arnBCADTEF, and the PhoP-PhoQ two-component system. Conversely, the genes for the synthesis of PQS were strongly down-regulated in PAO-SCV. Finally, genomic analysis revealed the presence of mutations in phoP and phoQ genes as well as in the mexZ gene encoding a repressor of the mexXY and mexAB-oprM genes. Only one mutation occurred only in REV, at nucleotide 1020 of the tufA gene, a paralog of tufB, both encoding the elongation factor Tu, causing a change of the rarely used aspartic acid codon GAU to the more common GAC, possibly causing an increase of tufA mRNA translation. High expression of phoP and phoQ was confirmed for the SCV variant while the revertant showed expression levels reduced to wild-type levels. CONCLUSIONS: By combining data coming from phenotypic, gene expression and proteome analysis, we could demonstrate that resistance to aminoglycosides in one SCV mutant is multifactorial including overexpression of efflux mechanisms, LPS modification and is accompanied by a drastic down-regulation of the

  1. The efficacy of immediate versus delayed antibiotic administration on bacterial growth and biofilm production of selected strains of uropathogenic Escherichia coli and Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Leah Gandee

    2015-02-01

    Full Text Available Purpose The treatment of urinary tract infections (UTI with antibiotics is commonly used, but recurrence and antibiotic resistance have been growing and concerning clinicians. We studied whether the rapid onset of a protective biofilm may be responsible for the lack of effectiveness of antibiotics against selected bacteria. Materials and Methods Two established uropathogenic Escherichia coli strains, UTI89 and CFT073, and two Pseudomonas aeruginosa strains, PA01 and Boston-41501, were studied to establish a reliable biofilm formation process. Bacterial growth (BG was determined by optical density at 600 nm (OD 600 using a spectrophotometer, while biofilm formation (BF using crystal violet staining was measured at OD 550. Next, these bacterial strains were treated with clinically relevant antibiotics, ciprofloxacin HCl (200 ng/mL and 2 μg/mL, nitrofurantoin (20 μg/mL and 40 μg/mL and ampicillin (50 μg/mL at time points of 0 (T0 or after 6 hours of culture (T6. All measurements, including controls (bacteria -1% DMSO, were done in triplicates and repeated three times for consistency. Results The tested antibiotics effectively inhibited both BG and BF when administered at T0 for UPEC strains, but not when the antibiotic administration started 6 hours later. For Pseudomonas strains, only Ciprofloxacin was able to significantly inhibit bacterial growth at T0 but only at the higher concentration of 2 μg/mL for T6. Conclusion When established UPEC and Pseudomonas bacteria were allowed to culture for 6 hours before initialization of treatment, the therapeutic effect of selected antibiotics was greatly suppressed when compared to immediate treatment, probably as a result of the protective nature of the biofilm.

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

    International Nuclear Information System (INIS)

    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.

  3. Commensal Pseudomonas Species Isolated from Wastewater and Freshwater Milieus in the Eastern Cape Province, South Africa, as Reservoir of Antibiotic Resistant Determinants

    Directory of Open Access Journals (Sweden)

    Anthony I. Okoh

    2012-07-01

    Full Text Available Pseudomonas species are opportunistic pathogens with implications in a wide range of diseases including cystic fibrosis and sickle cell anaemia. Because of their status as multidrug resistant (MDR and extremely drug resistant (XDR bacteria Pseudomonas species represent a threat to public health. Prevalence, antibiogram and associated antibiotic resistant genes of Pseudomonas species isolated from freshwater and mixed liquor environments in the Eastern Cape Province of South Africa were assessed. Polymerase chain reaction (PCR based technique was used to identify the isolates and screen for antibiotic resistant genes. The result shows occurrence of Pseudomonas spp. in freshwater and mixed liquor as follows: 71.42% and 37.5% (P. putida, 14.28% and 31.25% (P. flourescens, 7.14% and 6.25% (P. aeruginosa and 7.14% and 25% for other Pseudomonas species respectively. Disk diffusion antibiogram of the Pseudomonas isolates from the two locations showed 100% resistance to penicillin, oxacillin, clindamycin, rifampicin and 100% susceptibility to ciprofloxacin and gentamicin with varied percentage resistances to cephalothin, nalidixic acid, tetracycline, and ampicillin. The blaTEM antibiotic resistant gene was detected in 12.5% of P. putida, 57.14% of P. fluorescens, 100% P. aeruginosa and 40% in other Pseudomonas species. Similarly, Integrons conserved segment were detected in 12.5% of P. putida, 57.14% of P. fluorescens, 100% of P. aeruginosa and 40% of other Pseudomonas species. The presence of blaTEM gene and integrons conserved segment in some of the isolates is worrisome and suggest Pseudomonas species as important reservoirs of multidrug resistance genes in the Eastern Cape Province environment.

  4. 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. PMID:24077306

  5. Genetic Determinants Involved in the Susceptibility of Pseudomonas aeruginosa to  -Lactam Antibiotics

    OpenAIRE

    Alvarez-Ortega, C.; Wiegand, I.; Olivares, J.; Hancock, R. E. W.; Martinez, J.L.

    2010-01-01

    The resistome of P. aeruginosa for three β-lactam antibiotics, namely, ceftazidime, imipenem, and meropenem, was deciphered by screening a comprehensive PA14 mutant library for mutants with increased or reduced susceptibility to these antimicrobials. Confirmation of the phenotypes of all selected mutants was performed by Etest. Of the total of 78 confirmed mutants, 41 demonstrated a reduced susceptibility phenotype and 37 a supersusceptibility (i.e., altered intrinsic resistance) phenotype, w...

  6. Activity and interactions of antibiotic and phytochemical combinations against Pseudomonas aeruginosa in vitro

    Directory of Open Access Journals (Sweden)

    Premkumar Jayaraman, Meena K Sakharkar, Chu Sing Lim, Thean Hock Tang, Kishore R. Sakharkar

    2010-01-01

    Full Text Available In this study the in vitro activities of seven antibiotics (ciprofloxacin, ceftazidime, tetracycline, trimethoprim, sulfamethoxazole, polymyxin B and piperacillin and six phytochemicals (protocatechuic acid, gallic acid, ellagic acid, rutin, berberine and myricetin against five P. aeruginosa isolates, alone and in combination are evaluated. All the phytochemicals under investigation demonstrate potential inhibitory activity against P. aeruginosa. The combinations of sulfamethoxazole plus protocatechuic acid, sulfamethoxazole plus ellagic acid, sulfamethoxazole plus gallic acid and tetracycline plus gallic acid show synergistic mode of interaction. However, the combinations of sulfamethoxazole plus myricetin shows synergism for three strains (PA01, DB5218 and DR3062. The synergistic combinations are further evaluated for their bactericidal activity against P. aeruginosa ATCC strain using time-kill method. Sub-inhibitory dose responses of antibiotics and phytochemicals individually and in combination are presented along with their interaction network to suggest on the mechanism of action and potential targets for the phytochemicals under investigation. The identified synergistic combinations can be of potent therapeutic value against P. aeruginosa infections. These findings have potential implications in delaying the development of resistance as the antibacterial effect is achieved with lower concentrations of both drugs (antibiotics and phytochemicals.

  7. Antibiotic resistance profiles of Pseudomonas aeruginosa isolated from various Greek aquatic environments.

    Science.gov (United States)

    Olga, Pappa; Apostolos, Vantarakis; Alexis, Galanis; George, Vantarakis; Athena, Mavridou

    2016-05-01

    A large number of antibiotic-resistantP. aeruginosaisolates are continuously discharged into natural water basins mainly through sewage. However, the environmental reservoirs of antibiotic resistance factors are poorly understood. In this study, the antibiotic resistance patterns of 245 isolates from various aquatic sites in Greece were analysed. Twenty-three isolates with resistance patterns cefotaxime-aztreonam-ceftazidime, cefotaxime-aztreonam-meropenem, cefotaxime-ceftazidime-meropenem, cefotaxime-ceftazidime-aztreonam-meropenem and cefotaxime-ceftazidime-cefepime-aztreonam-meropenem were screened phenotypically for the presence of extended spectrum β-lactamases (ESBLs), while 77 isolates with various resistant phenotypes were screened for the presence of class 1 and class 2 integrase genes. The aztreonam-resistant isolates and ESBL producers were the main resistant phenotypes in all habitats tested. In 13/77 isolates class 1 integron was detected, while all tested isolates were negative for the presence of the class 2 integrase gene. CTX-M group 9 β-lactamase was present in a small number of isolates (three isolates) highlighting the emergence of ESBL genes in aquatic environments. As a conclusion, it seems that Greek water bodies could serve as a potential reservoir of resistantP. aeruginosaisolates posing threats to human and animal health. PMID:26917780

  8. 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; Ng, Yin; Gram, Lone

    Introduction: The foodborne pathogen Listeria monocytogenes can cause the severe infection listeriosis, which have up to 20-30% mortality, but if discovered in time, it can be treated with antibiotics. Most antibiotics are bacteriostatic against L. monocytogenes. This could be due to the coexiste...

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

    Science.gov (United States)

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

    1995-11-01

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

  10. 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

  11. [Quorum sensing systems of regulation, synthesis of phenazine antibiotics, and antifungal (corrected) activity in rhizospheric bacterium Pseudomonas chlororaphis 449].

    Science.gov (United States)

    Veselova, M a; Klein, Sh; Bass, I A; Lipasova, V A; Metlitskaia, A Z; Ovadis, M I; Chernin, L S; Khmel', I A

    2008-12-01

    Strain Pseudomonas chlororaphis 449, an antagonist of a broad spectrum of phytopathogenic microorganisms isolated from the maize rhizosphere, was shown to produce three phenazine antibiotics: phenazine-1-carboxylic acid (PCA), 2-hydroxylphenazine-1-carboxylic acid (2-OH-PCA), and 2-hydroxylphenazine (2-OH-PHZ). Two Quorum Sensing (QS) systems of regulation were identified: PhzIR and CsaI/R. Genes phzI and csaI were cloned and sequenced. Cells of strain 449 synthesize at least three types of AHL: N-butanoyl-L-homoserine lactone (C4-AHL), N-hexanoyl-L-homoserine lactone (C6-AHL), and N-(3-oxo-hexanoyl)-L-homoserine lactone (30C6-AHL). Transposon mutagenesis was used to generate mutants of strain 449 deficient in synthesis of phenazines, which carried inactivated phzA and phzB genes of the phenazine operon and gene phzO. Mutations phzA- and phzB-caused a drastic reduction in the antagonistic activity of bacteria toward phytopathogenic fungi. Both mutants lost the ability to protect cucumber and leguminous plants against phytopathogenic fungi Rhizoctonia solani and Sclerotinia sclerotiorum. These results suggest a significant role of phenazines in the antagonistic activity of P. chlororaphis 449. PMID:19178080

  12. Antimicrobial and antifouling efficacy of urinary catheters impregnated with a combination of macrolide and fluoroquinolone antibiotics against Pseudomonas aeruginosa.

    Science.gov (United States)

    Saini, Hina; Chhibber, Sanjay; Harjai, Kusum

    2016-05-01

    The incidence of catheter associated urinary tract infections (CAUTIs) is increasing worldwide. This study was designed to modify a biomaterial by impregnating a silicone urinary catheter with combination of a macrolide, azithromycin (AZM) and a fluoroquinolone, ciprofloxacin (CIP). Drug release profiles showed slow yet continuous release of antibiotics from catheters for one month. In vitro efficacy testing showed that group B catheters [3% (w v(-1)) CIP + 6% (w v(-1)) AZM] outperformed group A catheters [2% (w v(-1)) CIP + 5% (w v(-1)) AZM] by (1) showing larger zones of inhibition (>31 mm) compared to group A (<28 mm) for up to 30 days against Pseudomonas aeruginosa PAO1; (2) killing adhered bacteria in 24 h compared to 24-48 h in group A; (3) showing longer antimicrobial durability for four weeks; and (4) exhibiting a stable real-time shelf life of one year, suggesting that these catheters can be explored in clinical settings, especially in long-term CAUTI. PMID:26982572

  13. Field evaluation of different antibacterial antibiotic and plant extracts against bacterial blight of soybean caused by pseudomonas syringae pv. glycinea

    Directory of Open Access Journals (Sweden)

    G.P. Jagtap

    2012-08-01

    Full Text Available A field experiment was carried out to study effect of different antibacterial antibiotics and plant extracts against bacterial blight of soybean caused by Pseudomonas syringae pv. glycinea. The highest mean per cent disease incidence 35.51 per cent was observed in poushamycin treatment. The lowest mean per cent disease incidence 12.74 per cent was found in treatment streptocycline 100 ppm + Copper oxychloride (@0.25% and recorded highest seed yield (2605 kg/ha and test weight (14.33 g is superior over rest of treatments which was at par with streptocycline 100 ppm (14.28%, copper oxychloride (19.40 and Bactinashak 500 ppm (25.12%. The highest mean per cent disease incidence 28.16 per cent was observed in Tulsi and lowest mean per cent disease incidence 15.03 per cent was found in treatment Neem. Sprays of Neem is superior over rest of treatment minimum disease incidence was observed in this treatments (11.00 % and which was at par with Ginger Garlic, Onion and Tulsi.

  14. 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...

  15. 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

    conclusion, serotype switching in combination with acquisition of an antibiotic resistance determinant most likely contributed to the dissemination of the O12 serotype in clinical settings. Infection rates in hospital settings by multidrug-resistant (MDR) Pseudomonas aeruginosa clones have increased during...... switching was the result of horizontal transfer and genetic recombination of lipopolysaccharide (LPS) biosynthesis genes originating from an MDR taxonomic outlier P. aeruginosa strain. Moreover, the recombination event also resulted in acquisition of antibiotic resistance genes. These results impact on our...... 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...

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

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, Peter Østrup; Burmølle, Mette;

    2005-01-01

    The opportunistic human pathogen Pseudomonas aeruginosa is the predominant micro-organism of chronic lung infections in cystic fibrosis (CF) patients. P. aeruginosa colonizes the CF lungs by forming biofilm structures in the alveoli. In the biofilm mode of growth the bacteria are highly tolerant to...... 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...

  17. Antibiotic Resistance of Pseudomonas aeruginosa in Pneumonia at a Single University Hospital Center in Germany over a 10-Year Period.

    Directory of Open Access Journals (Sweden)

    Josef Yayan

    Full Text Available Pseudomonas aeruginosa is a common cause of community-acquired and nosocomial-acquired pneumonia. The development of resistance of P. aeruginosa to antibiotics is increasing globally due to the overuse of antibiotics. This article examines, retrospectively, the antibiotic resistance in patients with community-acquired versus nosocomial-acquired pneumonia caused by P. aeruginosa or multidrug-resistant (MDR P. aeruginosa.Data from patients with community-acquired and nosocomial-acquired pneumonia caused by P. aeruginosa and MDR P. aeruginosa were collected from the hospital charts at the HELIOS Clinic, Witten/Herdecke University, Wuppertal, Germany, between January 2004 and August 2014. An antibiogram was created from all study patients with community-acquired and nosocomial-acquired pneumonia caused by P. aeruginosa or MDR P. aeruginosa.A total of 168 patients with mean age 68.1 ± 12.8 (113 [67.3% males and 55 [32.7%] females were identified; 91 (54.2% had community-acquired and 77 (45.8% had nosocomial-acquired pneumonia caused by P. aeruginosa. Patients with community-acquired versus nosocomial-acquired pneumonia had a mean age of 66.4 ± 13.8 vs. 70.1 ± 11.4 years [59 vs. 54 (64.8% vs. 70.1% males and 32 vs. 23 (35.2% vs. 29.9% females]. They included 41 (24.4% patients with pneumonia due to MDR P. aeruginosa: 27 (65.9% community-acquired and 14 (34.1% nosocomial-acquired cases. P. aeruginosa and MDR P. aeruginosa showed a very high resistance to fosfomycin (community-acquired vs. nosocomial-acquired (81.0% vs. 84.2%; 0 vs. 85.7%. A similar resistance pattern was seen with ciprofloxacin (35.2% vs. 24.0%; 70.4% vs. 61.5%, levofloxacin (34.6% vs. 24.5%; 66.7% vs. 64.3%, ceftazidime (15.9% vs. 30.9; 33.3% vs. 61.5%, piperacillin (24.2% vs. 29.9%; 44.4% vs. 57.1%, imipenem (28.6% vs. 27.3%; 55.6% vs. 50.0%, piperacillin and tazobactam (23.1% vs. 28.6%; 44.4% vs. 50.0%, tobramycin (28.0% vs. 17.2%; 52.0% vs. 27.3%, gentamicin (26.4% vs. 18.2%; 44

  18. Antibiotic susceptibility pattern and analysis of plasmid profiles of Pseudomonas aeruginosa from human, animal and plant sources.

    Science.gov (United States)

    Odumosu, Bamidele Tolulope; Ajetunmobi, Olabayo; Dada-Adegbola, Hannah; Odutayo, Idowu

    2016-01-01

    Multidrug resistant organisms (MDROs) constitute a major public health threat globally. Clinical isolates of Pseudomonas aeruginosa remains one of the most studied MDROs however there is paucity of information regarding the susceptibility of its animal and plants isolates to antipseudomonas drug in Nigeria. From a total of 252 samples consisting of plants, animals and clinical samples, 54, 24 and 22 P. aeruginosa were isolated from vegetables, animals and clinical sources respectively. All the isolates were identified by standard biochemical methods. Antimicrobial susceptibility testing (AST) of the 100 P. aeruginosa isolates against 7 antipseudomonal drugs was carried out by disk diffusion method, the phenotypic detection of ESBL was done by double disk synergy test (DDST) while plasmid extraction on 20 selected isolates based on their resistance to 2 or more classes of antibiotics was carried out by alkaline lysis method and analysed with Lambda DNA/Hind lll marker respectively. The AST results revealed highest resistance of 91 and 55 % to ceftazidime and carbenicillin respectively while highest susceptibilities of 99 % for piperacillin-tazobactam and imipenem were recorded in overall assay. Fifteen out of 100 isolates specifically (10) from vegetables, (3) clinical and (2) poultry isolates showed synergy towards the beta-lactamase inhibitor indicating production of ESBL by DDST method. Detection of plasmids was among vegetable (n = 4), poultry (n = 4), cow (n = 3) and clinical isolates (n = 1). Plasmid profile for the selected isolates revealed 6 of the strains had one plasmids each while 5 strains possessed 2-4 plasmids and 1 strain had 5 plasmids. The sizes of the plasmid range from Plants and animal isolates of P. aeruginosa harbouring multiple mechanisms of resistance is of concern due to the danger it poses on the public health. PMID:27610300

  19. 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.

  20. Emergence of Multidrug-Resistant Pseudomonas aeruginosa: Detection of Isolates harboring blaCTX gene causing infections in hospital and determination of their susceptibility to antibiotics

    Directory of Open Access Journals (Sweden)

    Z Rabani

    2015-11-01

    Full Text Available Background & aim: Because of its ubiquitous nature, ability to survive in moist environments, and innate resistance to many antibiotics and antiseptics, P. aeruginosa is a common pathogen in hospitals. The goals of this study were detection of Psudomonas aeruginosa harboring blaCTX gene causing infections in hospitals and determination of their susceptibility to antibiotics and ESBL production. Methods: In the present cross-sectional study, clinical samples from hospitalized patients were collected and culture was done on apropriate media. Final identification was performed using biochemical tests and API 20NE system. According to the protocol CLSI 2014 disc diffusion, combination disk, modified hodge test (MHT and E-test were used for antibiotic susceptibility, ESBL production, carbapenemas production, and MIC values of imipenem respectively. The blaCTX gene was detected in the isolates by PCR molecular method. Results: In the current study, 45 isolates of Pseudomonas aeroginosa were obtained from hospitalized patients, consisting of 19 males (42.2% and 26 females (57.8%. As observed, 57.8% (26 strains of isolates were recovered from sputum. The most effective antibiotics against isolates were amikacin and colistin with 97.8% suseptibility whereas the highest resistance was to cefotaxime (97.8%. As revealed 77.8% of isolates showed response to group 2 carbapenems (imipenem, meropenem. All imipenem resistant strains had the MIC more than 32. Seventeen strains (37.7% were  showed resistant to quinolones (ciprofloxacin, norfloxacin. The results of PCR on blaCTX gene indicated that 15.5% of the isolates possess the gene. Conclusion: Carbapenem group of antibiotic in 22% of infections caused by Pseudomonas aeruginosa were ineffective and indiscriminate prescribing of these drugs will increase the ratet of resistance.

  1. 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. PMID:26580742

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

    OpenAIRE

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

    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...

  3. Negative Cross-Communication among Wheat Rhizosphere Bacteria: Effect on Antibiotic Production by the Biological Control Bacterium Pseudomonas aureofaciens 30-84

    OpenAIRE

    Morello, J. E.; Pierson, E.A.; Pierson, L S

    2004-01-01

    Phenazine antibiotic production in the biological control bacterium Pseudomonas aureofaciens 30-84 is regulated in part via the PhzR/PhzI N-acyl homoserine lactone (AHL) system. Previous work showed that a subpopulation of the wheat rhizosphere community positively affected phenazine gene expression in strain 30-84 via AHL signals (E. A. Pierson, D. W. Wood, J. A. Cannon, F. M. Blachere, and L. S. Pierson III, Mol. Plant-Microbe Interact. 11:1078-1084, 1998). In the present work, a second sub...

  4. 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....

  5. 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

    OBJECTIVE: To assess the efficacy and safety of meropenem, administered on a compassionate basis to 62 cystic fibrosis (CF) patients (age: 24plus minus6 years) with hypersensitivity reactions to beta-lactam antibiotics and/or infection by bacteria resistant to other antibiotics. METHODS: Fifty......-seven patients were chronically infected with Pseudomonas aeruginosa and 5 with Burkholderia cepacia. In total, 124 courses (1 to 6/patient) of meropenem, 2 g three times a day by intravenous infusion (10 to 15 min) for 14 days, were administered. RESULTS: During treatment for P. aeruginosa the mean increase in...... 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...

  6. 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...

  7. Use of Arabidopsis thaliana and Pseudomonas syringae in the Study of Plant Disease Resistance and Tolerance

    OpenAIRE

    Bent, Andrew F.; Kunkel, Barbara N.; Innes, Roger W.; Staskawicz, Brian J.

    1993-01-01

    The interaction between Arabidopsis thaliana and the bacterium Pseudomonas syringae is being developed as a model experimental system for plant pathology research. Race-specific ("gene-for-gene") resistance has been demonstrated for this interaction, and pathogen genes that determine avirulence have been isolated and characterized. Because certain lines of both Arabidopsis and soybean are resistant to bacteria carrying the avirulence genes avrRpt2 and avrB, extremely similar pathogen recognit...

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

    Directory of Open Access Journals (Sweden)

    Bright Igere

    2012-06-01

    Full Text Available 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.

  9. Molecular detection of antibiotic related genes from Pseudomonas aeruginosa FP6, an antagonist towards Rhizoctonia solani and Colletotrichum gloeosporioides

    OpenAIRE

    BAKTHAVATCHALU, Sasirekha; Shivakumar, Srividya; SULLIA, Shankar Bhat

    2013-01-01

    Despite the importance of antibiosis in biological control, little is known about the genes involved in antifungal activity. Therefore, the present study was aimed at identifying the location of the antagonistic gene(s) in Pseudomonas aeruginosa FP6 towards Rhizoctonia solani and Colletotrichum gloeosporioides using a PCR-based approach. A new bacterial strain, designated as FP6, was isolated from rhizospheric soil and identified as a member of Pseudomonas aeruginosa based on 16S rRNA analysi...

  10. 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

  11. Isolation of TNT tolerant pseudomonas species (Strain KA from TNT contaminated soil biotransformation of TNT

    Directory of Open Access Journals (Sweden)

    Avinash M. Tope

    2001-04-01

    Full Text Available "A 2,4,6-trinitrotoluene (TNT utilising bacterium, Pseudomonas species (strain KA was isolated from soils of a munitions processing unit and studied for itsability to grow and metabolise TNT. The result indicated that the isolate could grow aerobically in a minimal salt medium containing 0.25 mM/l TNT at 30 °C. It could completely transform 0.25 mM/l TNT in 5 days giving 2-isomeric monoaminodinitrotoluenes, namely 4-aminodinitrotoluene and 2-aminodinitrotoluene. Products of TNT transformation were analysed and confirmed by thin layer chromatography and gas chromatography coupled with mass spectrometry. Both, growth of the isolate and biotransformation rates were better supported on sugar and ammonium salt when added to the medium separately. Pseudomonas species (strain KA showed maximum TNT transformation efficiency in the presence of mannose. For degradation of TNT, this strain can be employed to initiate the process in association with the other microbial members that can collectively degrade TNT .

  12. 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

    The chronic Pseudomonas aeruginosa infection of the lungs of cystic fibrosis (CF) patients is characterized by the biofilm mode of growth and chronic inflammation dominated by polymorphonuclear leukocytes (PMNs). A high percentage of P. aeruginosa strains show high frequencies of mutations (hyper...

  13. Antibiotic Resistance and Heavy Metals Tolerance in Gram-Negative Bacteria from Diseased American Bullfrog (Rana catesbeiana) Cultured in Malaysia

    Institute of Scientific and Technical Information of China (English)

    M Na-jian; S W Lee; W Wendy; L W Tee; M Nadirah; S H Faizah

    2009-01-01

    A total of 140 bacterial isolates have been successfully isolated from various organs of diseased American bullfrog (Rana catesbeiana) cultured in Malaysia. The most frequently isolated bacteria was Edwardsiella spp. (46 isolates) followed by Aeromonas spp. (33 isolates), Flavobacterium spp. (31 isolates), and Vibrio spp. (30 isolates). Majority of the bacterial isolates were found sensitive to furazolidone (85.0%), chloramphenicol (85.0%), oxolinic acid (90.0%), florfenicol (95.0%), and flumequine (97.5%). On the other hand, most of the bacterial isolates were resistant to oleandomycin (77.5%) and lincomycin (87.5%). Nitrofurantoin and flumequine can be inhibited the growth of all of Vibrio spp. whereas all isolates of Edwardsiella spp. were found sensitive to florfenicol and flumequine. Multiple antibiotic resistance (MAR) index were in range of 0.30-0.40, indicating that bacterial isolates from cultured bullfrogs may have received high risk exposure to the tested antibiotics. In addition, 90-100% of the isolates were resistant to copper, cadmium, and chromium. These results provided insight information on tolerance level of bacterial isolates from cultured bullfrogs to 21 antibiotics as well as heavy metals.

  14. 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

    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...... cystic fibrosis (CF) patient at different time periods during chronic lung infection. Methods: BALB/c mice were challenged with alginate-embedded mucoid clinical isolates isolated in 1988, 1997 or 2003. Mice were euthanized on day 1, 2 or 3 post-infection for estimation of quantitative bacteriology......: 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...

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

    OpenAIRE

    Kivisaar Maia; Lilje Liisa; Ilves Heili; Putrinš Marta; Hõrak Rita

    2010-01-01

    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 pheno...

  16. Complete Genome Sequence of the Rhizobacterium Pseudomonas trivialis Strain IHBB745 with Multiple Plant Growth-Promoting Activities and Tolerance to Desiccation and Alkalinity

    OpenAIRE

    Gulati, Arvind; Swarnkar, Mohit Kumar; Vyas, Pratibha; Rahi, Praveen; Thakur, Rishu; Thakur, Namika; Singh, Anil Kumar

    2015-01-01

    The complete genome sequence of 6.45 Mb is reported here for Pseudomonas trivialis strain IHBB745 (MTCC 5336), which is an efficient, stress-tolerant, and broad-spectrum plant growth-promoting rhizobacterium. The gene-coding clusters predicted the genes for phosphate solubilization, siderophore production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, indole-3-acetic acid (IAA) production, and stress response.

  17. Complete Genome Sequence of the Rhizobacterium Pseudomonas trivialis Strain IHBB745 with Multiple Plant Growth-Promoting Activities and Tolerance to Desiccation and Alkalinity.

    Science.gov (United States)

    Gulati, Arvind; Swarnkar, Mohit Kumar; Vyas, Pratibha; Rahi, Praveen; Thakur, Rishu; Thakur, Namika; Singh, Anil Kumar

    2015-01-01

    The complete genome sequence of 6.45 Mb is reported here for Pseudomonas trivialis strain IHBB745 (MTCC 5336), which is an efficient, stress-tolerant, and broad-spectrum plant growth-promoting rhizobacterium. The gene-coding clusters predicted the genes for phosphate solubilization, siderophore production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, indole-3-acetic acid (IAA) production, and stress response. PMID:26337878

  18. 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...

  19. Induced drought tolerance through wild and mutant bacterial strain Pseudomonas simiae in mung bean (Vigna radiata L.).

    Science.gov (United States)

    Kumari, Sarita; Vaishnav, Anukool; Jain, Shekhar; Varma, Ajit; Choudhary, Devendra Kumar

    2016-01-01

    The present study focused on the overproducing mutant of a plant growth promoting rhizobacterium (PGPR) Pseudomonas simiae strain AU (MTCC-12057) for significant drought tolerance in mung bean plants. Five mutants namely AU-M1, AU-M2, AU-M3, AU-M4 and AU-M5 were made after treatment of wild type strain with N-methyl-N-nitro-N-nitrosoguanidine. Mutant strain AU-M4 was recorded for enhanced ACC deaminase (ACC-D) activity, indole acetic acid (IAA) production and inorganic phosphate (Pi) solubilization compared to wild strain and other four mutant strains under drought condition. AU-M4 showed higher phosphate solubilization index (8.17) together with higher ACC-D activity (98 nmol/mg/h) and IAA concentration (69.35 µg/ml) compared with the wild type P. simiae strain AU ACC-D activity (79 nmol/mg/h) and IAA concentration (38.98 µg/ml) respectively. In this report, we investigated the effect of both wild and mutant type bacterial strain on mung bean plants under drought stress. Results showed that mutant AU-M4 and wild type strain AU inoculated plants exhibited superior tolerance against drought stress, as shown by their enhanced plant biomass (fresh weight), higher water content, higher proline accumulation and lower osmotic stress injury. Mutant AU-M4 and wild strain AU inoculated plants reduced the ethylene level by 59 and 45% respectively, compared to the control under stress condition. Furthermore, bacterial inoculated plants showed enhanced induced systemic drought tolerance by reducing stomata size and net photosynthesis resulting higher water content in mung bean plants that may help in survival of plants during drought condition. To mitigate the effects of drought stress, use of PGPR will be needed to ensure sufficient production of food from crop plants. Taking current leads available, concerted future research is needed in this area, particularly on field evaluation with application of potential microorganisms. PMID:26712619

  20. 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

    Combination therapy with several antibiotics is one strategy that has been applied in order to limit the spread of antimicrobial resistance. We compared the de novo evolution of resistance during combination therapy with the β-lactam ceftazidime and the fluoroquinolone ciprofloxacin with the...

  1. 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

  2. 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)

    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)

  3. Regulatory aspects of Phase 3 endpoints for new inhaled antibiotics for cystic fibrosis patients with chronic Pseudomonas aeruginosa infections.

    Science.gov (United States)

    Montgomery, Alan Bruce; Abuan, Tammy; Yeager, Melissa A

    2012-08-01

    Available regulatory guidelines for developing inhaled anti-infective therapies offer general advice, but specific guidance often provides conflicting and outdated advice in regard to clinical trial design. For instance, the availability of two approved drugs makes the conduct of placebo-controlled trials longer than 28 days problematic. Comparator drugs require use per the product label, making comparator trials difficult to blind as taste, foaming, regimen, device, and delivery time differences are present. Currently, there is no consensus on the most appropriate endpoints for evaluation of aerosolized antimicrobials. FEV(1) is a surrogate endpoint that it is a predictor of mortality--it is standardized, reproducible, noninvasive, simple, and inexpensive to perform but small statistically significant changes may not be clinically important. FEV(1) improvement also has a ceiling effect in patients with mild lung function impairment and spirometry cannot be reliably done in patients under the age of 6 years. A patient-reported outcome is a promising clinical endpoint. However, there is not currently an accepted tool that can be used as a primary endpoint for the FDA or the EMA, although the latter recognizes the CFQ-R as a validated secondary endpoint and the FDA grandfathered acceptance of the CFQ-R respiratory domain in the pivotal aztreonam for inhalation study. Exacerbations are an important clinical endpoint that reflects morbidity and are a major driver of cost of care, but they occur infrequently and a standardized definition has not been reached. Furthermore, an exacerbation endpoint may fail even with an otherwise effective antibiotic therapy. Regulatory authorities will have a difficult time approving any new inhaled antibiotic based on one clinical endpoint alone. PMID:22857271

  4. 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

  5. Comparative efficacy and tolerance of ibuprofen syrup and acetaminophen syrup in children with pyrexia associated with infectious diseases and treated with antibiotics.

    Science.gov (United States)

    Autret, E; Breart, G; Jonville, A P; Courcier, S; Lassale, C; Goehrs, J M

    1994-01-01

    A double-blind, randomised, parallel group study has been done comparing the efficacy and tolerability of 7.5 mg/kg ibuprofen syrup (n = 77) and 10 mg.kg-1 acetaminophen syrup (n = 77) in 154 children (6 months to 5 years) with fever (> or = 38 degrees C) associated with infectious diseases and treated with antibiotic therapy. The area under the percentage reduction in temperature curve captured the net effect of each drug and provided the best estimate for comparison of efficacy during a defined period. Temperature evolution over time was not significantly different between the two groups. Nevertheless, the temperature reduction over the first 4 h of treatment (H0-H4) was significantly higher after ibuprofen (60%) than acetaminophen (45%). Both ibuprofen and acetaminophen were well tolerated. In conclusion, significant antipyretic activity, good tolerability and its availability as a syrup make ibuprofen an effective means of fever control in children. PMID:8070499

  6. 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...... 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....

  7. Use of In-Biofilm Expression Technology To Identify Genes Involved in Pseudomonas aeruginosa Biofilm Development†

    OpenAIRE

    Finelli, Antonio; Gallant, Claude V.; Jarvi, Keith; Burrows, Lori L.

    2003-01-01

    Mature Pseudomonas aeruginosa biofilms form complex three-dimensional architecture and are tolerant of antibiotics and other antimicrobial compounds. In this work, an in vivo expression technology system, originally designed to study virulence-associated genes in complex mammalian environments, was used to identify genes up-regulated in P. aeruginosa grown to a mature (5-day) biofilm. Five unique cloned promoters unable to promote in vitro growth in the absence of purines after recovery from ...

  8. 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.

    Science.gov (United States)

    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 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. PMID:26587344

  9. 荧光假单胞菌抗生性代谢产物合成相关基因的研究现状%The Antibiotic Metabolites Genes of Pseudomonas fluorescens

    Institute of Scientific and Technical Information of China (English)

    杨毅; 李治; 高玲霞; 孙燕

    2012-01-01

    Pseudomonas fluorescens is an important kind of plant growth-promoting rhizobacteria ( PGPR ). It can produce many secondary metabolites, such as pyoluteorin, 2, 4-diacetylphloroglucinol, pyrrolnitrin and phenazine-1 -carboxyl acid. These antibiotics play a major role in suppression of many pathogens. The synthesis mechanisms of the secondary metabolites in Pseudomonas fluorescens, especially the structures and functions of the related genes were summarized. At the same time, the applications of Pseudomonas fluorescens in biological control are presented.%荧光假单胞菌(Pseudomonas fluorescens)是一种重要的植物根际促生菌,它能够产生藤黄绿脓菌素、2,4-二乙酰基藤黄酚、硝吡咯菌素、吩嗪-1-羧酸等抗生性次级代谢产物,可抑制多种病原物,在农作物土传病害的生物防治研究中具有重要意义.总结了荧光假单胞菌中已确立的抗生性次级代谢产物的合成机制,重点阐述了相关基因的结构、功能,以及利用生物工程技术对荧光假单胞菌进行遗传操作的最新进展,同时对荧光假单胞菌在生物防治中的应用和其作为生防菌剂的前景进行了展望.

  10. 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, P<0.001). This effect was not delayed and it was therefore identified both by distributed lags analysis and the Pearson'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. PMID:21277747

  11. Interspecies signalling via the Stenotrophomonas maltophilia diffusible signal factor influences biofilm formation and polymyxin tolerance in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Ryan, R.P.; Fouhy, Y.; Garcia, B.F.; Watt, S.A.; Niehaus, K.; Yang, Liang; Tolker-Nielsen, Tim; Dow, J.M.

    2008-01-01

    Interspecies signalling through the action of diffusible signal molecules can influence the behaviour of organisms growing in polymicrobial communities. Stenotrophomonas maltophilia and Pseudomonas aeruginosa occur ubiquitously in the environment and can be found together in diverse niches...... including the rhizosphere of plants and the cystic fibrosis lung. In mixed species biofilms, S. maltophilia substantially influenced the architecture of P. aeruginosa structures, which developed as extended filaments. This effect depended upon the synthesis of the diffusible signal factor (DSF) by S....... maltophilia and could be mimicked by the addition of synthetic DSF. This response of P. aeruginosa to DSF required PA1396, a sensor kinase with an input domain of related amino acid sequence to the sensory input domain of RpfC, which is responsible for DSF perception in xanthomonads. Mutation of PA1396 or...

  12. Transcriptional regulation of multi-drug tolerance and antibiotic-induced responses by the histone-like protein Lsr2 in M. tuberculosis.

    Directory of Open Access Journals (Sweden)

    Roberto Colangeli

    2007-06-01

    Full Text Available Multi-drug tolerance is a key phenotypic property that complicates the sterilization of mammals infected with Mycobacterium tuberculosis. Previous studies have established that iniBAC, an operon that confers multi-drug tolerance to M. bovis BCG through an associated pump-like activity, is induced by the antibiotics isoniazid (INH and ethambutol (EMB. An improved understanding of the functional role of antibiotic-induced genes and the regulation of drug tolerance may be gained by studying the factors that regulate antibiotic-mediated gene expression. An M. smegmatis strain containing a lacZ gene fused to the promoter of M. tuberculosis iniBAC (PiniBAC was subjected to transposon mutagenesis. Mutants with constitutive expression and increased EMB-mediated induction of PiniBAC::lacZ mapped to the lsr2 gene (MSMEG6065, a small basic protein of unknown function that is highly conserved among mycobacteria. These mutants had a marked change in colony morphology and generated a new polar lipid. Complementation with multi-copy M. tuberculosis lsr2 (Rv3597c returned PiniBAC expression to baseline, reversed the observed morphological and lipid changes, and repressed PiniBAC induction by EMB to below that of the control M. smegmatis strain. Microarray analysis of an lsr2 knockout confirmed upregulation of M. smegmatis iniA and demonstrated upregulation of genes involved in cell wall and metabolic functions. Fully 121 of 584 genes induced by EMB treatment in wild-type M. smegmatis were upregulated ("hyperinduced" to even higher levels by EMB in the M. smegmatis lsr2 knockout. The most highly upregulated genes and gene clusters had adenine-thymine (AT-rich 5-prime untranslated regions. In M. tuberculosis, overexpression of lsr2 repressed INH-mediated induction of all three iniBAC genes, as well as another annotated pump, efpA. The low molecular weight and basic properties of Lsr2 (pI 10.69 suggested that it was a histone-like protein, although it did not

  13. Real-Time Solvent Tolerance Analysis of Pseudomonas sp. Strain VLB120ΔC Catalytic Biofilms▿ †

    OpenAIRE

    Halan, Babu; Schmid, Andreas; Buehler, Katja

    2010-01-01

    Biofilms are ubiquitous surface-associated microbial communities embedded in an extracellular polymeric (EPS) matrix, which gives the biofilm structural integrity and strength. It is often reported that biofilm-grown cells exhibit enhanced tolerance toward adverse environmental stress conditions, and thus there has been a growing interest in recent years to use biofilms for biotechnological applications. We present a time- and locus-resolved, noninvasive, quantitative approach to study biofil...

  14. In Vitro Screening for Abiotic Stress Tolerance in Potent Biocontrol and Plant Growth Promoting Strains of Pseudomonas and Bacillus spp.

    OpenAIRE

    G. Praveen Kumar; Mir Hassan Ahmed, S. K.; Suseelendra Desai; Leo Daniel Amalraj, E.; Abdul Rasul

    2014-01-01

    Plant growth promoting rhizobacteria (PGPR) has been identified as a group of microbes that are used for plant growth enhancement and biocontrol for management of plant diseases. The inconsistency in performance of these bacteria from laboratory to field conditions is compounded due to the prevailing abiotic stresses in the field. Therefore, selection of bacterial strains with tolerance to abiotic stresses would benefit the end-user by successful establishment of the strain for showing desire...

  15. Local adaptation is associated with zinc tolerance in Pseudomonas endophytes of the metal-hyperaccumulator plant Noccaea caerulescens.

    Science.gov (United States)

    Fones, H N; McCurrach, H; Mithani, A; Smith, J A C; Preston, G M

    2016-05-11

    Metal-hyperaccumulating plants, which are hypothesized to use metals for defence against pests and pathogens, provide a unique context in which to study plant-pathogen coevolution. Previously, we demonstrated that the high concentrations of zinc found in leaves of the hyperaccumulator Noccaea caerulescens provide protection against bacterial pathogens, with a potential trade-off between metal-based and pathogen-induced defences. We speculated that an evolutionary arms race between zinc-based defences in N. caerulescens and zinc tolerance in pathogens might have driven the development of the hyperaccumulation phenotype. Here, we investigate the possibility of local adaptation by bacteria to the zinc-rich environment of N. caerulescens leaves and show that leaves sampled from the contaminated surroundings of a former mine site harboured endophytes with greater zinc tolerance than those within plants of an artificially created hyperaccumulating population. Experimental manipulation of zinc concentrations in plants of this artificial population influenced the zinc tolerance of recovered endophytes. In laboratory experiments, only endophytic bacteria isolated from plants of the natural population were able to grow to high population densities in any N. caerulescens plants. These findings suggest that long-term coexistence with zinc-hyperaccumulating plants leads to local adaptation by endophytic bacteria to the environment within their leaves. PMID:27170725

  16. A tricistronic heat shock operon is important for stress tolerance of Pseudomonas putida and conserved in many environmental bacteria.

    Science.gov (United States)

    Krajewski, Stefanie S; Joswig, Matthias; Nagel, Miriam; Narberhaus, Franz

    2014-06-01

    Small heat shock proteins (sHsps) including the well-studied IbpA protein from Escherichia coli are molecular chaperones that bind to non-native proteins and prevent them from aggregation. We discovered an entirely unexplored tricistronic small heat shock gene cluster in Pseudomonas putida. The genes pp3314, pp3313 and pp3312 (renamed to hspX, hspY and hspZ respectively) are transcribed in a single transcript. In addition to σ(32) -dependent transcriptional control, translation of the first and second gene of the operon is controlled by RNA thermometers with novel architectures. Biochemical analysis of HspY, HspZ and P. putida IbpA demonstrated that they assemble into homo-oligomers of different sizes whose quaternary structures alter in a temperature-dependent manner. IbpA and HspY are able to prevent the model substrate citrate synthase from thermal aggregation in vitro. Increased stress sensitivity of a P. putida strain lacking HspX, HspY and HspZ revealed an important role of these sHsps in stress adaptation. The hspXYZ operon is conserved among metabolically related bacteria that live in hostile environments including polluted soils. This heat shock operon might act as a protective system to promote survival in such ecological niches. PMID:24612349

  17. A synergistic interaction between salt-tolerant Pseudomonas and Mesorhizobium strains improves growth and symbiotic performance of liquorice (Glycyrrhiza uralensis Fish.) under salt stress.

    Science.gov (United States)

    Egamberdieva, Dilfuza; Li, Li; Lindström, Kristina; Räsänen, Leena A

    2016-03-01

    Chinese liquorice (Glycyrrhiza uralensis Fish.) is a salt-tolerant medicinal legume that could be utilized for bioremediation of salt-affected soils. We studied whether co-inoculation of the symbiotic Mesorhizobium sp. strain NWXJ19 or NWXJ31 with the plant growth-promoting Pseudomonas extremorientalis TSAU20 could restore growth, nodulation, and shoot/root nitrogen contents of salt-stressed G. uralensis, which was grown in potting soil and irrigated with 0, 50, and 75 mM NaCl solutions under greenhouse conditions. Irrigation with NaCl solutions clearly retarded the growth of uninoculated liquorice, and the higher the NaCl concentration (75 and 100 mM NaCl), the more adverse is the effect. The two Mesorhizobium strains, added either alone or in combination with P. extremorientalis TSAU20, responded differently to the salt levels used. The strain NWXJ19 was a good symbiont for plants irrigated with 50 mM NaCl, whereas the strain NWXJ31 was more efficient for plants irrigated with water or 75 mM NaCl solution. P. extremorientalis TSAU20 combined with single Mesorhizobium strains alleviated the salt stress of liquorice plants and improved yield and nodule numbers significantly in comparison with single-strain-inoculated liquorice. Both salt stress and inoculation raised the nitrogen content of shoots and roots. The nitrogen contents were at their highest, i.e., 30 and 35 % greater compared to non-stressed uninoculated plants, when plants were inoculated with P. extremorientalis TSAU20 and Mesorhizobium sp. NWXJ31 as well as irrigated with 75 mM NaCl solution. From this study, we conclude that dual inoculation with plant growth-promoting rhizobacteria could be a new approach to improve the tolerance of G. uralensis to salt stress, thereby improving its suitability for the remediation of saline lands. PMID:26585446

  18. 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 at least seven secondary metabolites with anti-microbial activity. The production of two of these metabolites, 2,4-diacetylphloroglucinol (2,4-DAPG) and pyoluteorin, is coordinately regulated. Each of the two metabolites functions as an intercellular signal, ind...

  19. Toluene promotes lid 2 interfacial activation of cold active solvent tolerant lipase from Pseudomonas fluorescens strain AMS8.

    Science.gov (United States)

    Yaacob, Norhayati; Mohamad Ali, Mohd Shukuri; Salleh, Abu Bakar; Rahman, Raja Noor Zaliha Raja Abdul; Leow, Adam Thean Chor

    2016-07-01

    The utilization of cold active lipases in organic solvents proves an excellent approach for chiral synthesis and modification of fats and oil due to the inherent flexibility of lipases under low water conditions. In order to verify whether this lipase can function as a valuable synthetic catalyst, the mechanism concerning activation of the lid and interacting solvent residues in the presence of organic solvent must be well understood. A new alkaline cold-adapted lipase, AMS8, from Pseudomonas fluorescens was studied for its structural adaptation and flexibility prior to its exposure to non-polar, polar aprotic and protic solvents. Solvents such as ethanol, toluene, DMSO and 2-propanol showed to have good interactions with active sites. Asparagine (Asn) and tyrosine (Tyr) were key residues attracted to solvents because they could form hydrogen bonds. Unlike in other solvents, Phe-18, Tyr-236 and Tyr-318 were predicted to have aromatic-aromatic side-chain interactions with toluene. Non-polar solvent also was found to possess highest energy binding compared to polar solvents. Due to this circumstance, the interaction of toluene and AMS8 lipase was primarily based on hydrophobicity and molecular recognition. The molecular dynamic simulation showed that lid 2 (residues 148-167) was very flexible in toluene and Ca(2+). As a result, lid 2 moves away from the catalytic areas, leaving an opening for better substrate accessibility which promotes protein activation. Only a single lid (lid 2) showed the movement following interactions with toluene, although AMS8 lipase displayed double lids. The secondary conformation of AMS8 lipase that was affected by toluene observed a reduction of helical strands and increased coil structure. Overall, this work shows that cold active lipase, AMS8 exhibits distinguish interfacial activation and stability in the presence of polar and non-polar solvents. PMID:27474867

  20. Structure-Activity Relationships of a Diverse Class of Halogenated Phenazines That Targets Persistent, Antibiotic-Tolerant Bacterial Biofilms and Mycobacterium tuberculosis.

    Science.gov (United States)

    Garrison, Aaron T; Abouelhassan, Yasmeen; Norwood, Verrill M; Kallifidas, Dimitris; Bai, Fang; Nguyen, Minh Thu; Rolfe, Melanie; Burch, Gena M; Jin, Shouguang; Luesch, Hendrik; Huigens, Robert W

    2016-04-28

    Persistent bacteria, including persister cells within surface-attached biofilms and slow-growing pathogens lead to chronic infections that are tolerant to antibiotics. Here, we describe the structure-activity relationships of a series of halogenated phenazines (HP) inspired by 2-bromo-1-hydroxyphenazine 1. Using multiple synthetic pathways, we probed diverse substitutions of the HP scaffold in the 2-, 4-, 7-, and 8-positions, providing critical information regarding their antibacterial and bacterial eradication profiles. Halogenated phenazine 14 proved to be the most potent biofilm-eradicating agent (≥99.9% persister cell killing) against MRSA (MBEC antimicrobial peptide mimics that eradicate biofilms through the general lysing of membranes, HPs do not lyse red blood cells. HPs are promising agents that effectively target persistent bacteria while demonstrating negligible toxicity against mammalian cells. PMID:27018907

  1. The MexJK Efflux Pump of Pseudomonas aeruginosa Requires OprM for Antibiotic Efflux but Not for Efflux of Triclosan

    OpenAIRE

    Chuanchuen, Rungtip; Narasaki, Craig T.; Schweizer, Herbert P.

    2002-01-01

    Using the biocide triclosan as a selective agent, several triclosan-resistant mutants of a susceptible Pseudomonas aeruginosa strain were isolated. Cloning and characterization of a DNA fragment conferring triclosan resistance from one of these mutants revealed a hitherto uncharacterized efflux system of the resistance nodulation cell division (RND) family, which was named MexJK and which is encoded by the mexJK operon. Expression of this operon is negatively regulated by the product of mexL,...

  2. Capillary-Seeding Crystallization and Preliminary Crystallographic Analysis of a Solvent-Tolerant Elastase from Pseudomonas aeruginosa Strain K

    Directory of Open Access Journals (Sweden)

    Abu Bakar Salleh

    2013-08-01

    Full Text Available Seeding is a versatile method for optimizing crystal growth. Coupling this technique with capillary counter diffusion crystallization enhances the size and diffraction quality of the crystals. In this article, crystals for organic solvent-tolerant recombinant elastase strain K were successfully produced through microseeding with capillary counter-diffusion crystallization. This technique improved the nucleation success rate with a low protein concentration (3.00 mg/mL. The crystal was grown in 1 M ammonium phosphate monobasic and 0.1 M sodium citrate tribasic dihydrate pH 5.6. The optimized crystal size was 1 × 0.1 × 0.05 mm3. Elastase strain K successfully diffracted up to 1.39 Å at SPring-8, Japan, using synchrotron radiation for preliminary data diffraction analysis. The space group was determined to be monoclinic space group P1211 with unit cell parameters of a = 38.99 Ǻ, b = 90.173 Å and c = 40.60 Å.

  3. Influencing of the penetration of Pseudomonas aeruginosa into a 3-D epidermis model and the inactivation with tissue tolerable plasma

    Directory of Open Access Journals (Sweden)

    Lademann, Jürgen

    2009-12-01

    Full Text Available Aim: The biofilm formation plays a crucial role in the pathogenesis of many acute and subacute microbial infections as well as of chronic wounds. For the stimulation of wound healing tissue tolerable plasma (TTP is an alternative to antiseptic or chemotherapeutic therapies. The mechanical influence of argon plasma on the penetration of bacteria into the tissue related to the antimicrobial effect of the plasma is unknown. Hence the effects of argon plasma versus argon gas were examined for bacterial reduction as well as for the penetration depth of P. aeruginosa in a 3-D human epidermis model, the so-called combi-model.Method: 3-D NHEK cell cultures were inoculated with P. aeruginosa SG81 and treated after 20 min incubation with TTP. The distribution and penetration depth of the bacteria in the cell culture were compared by confocal laser scan microscope (CLSM between control and TTP effect. Result: The penetration of bacteria into the epidermis tissue and a significant reduction of the bacteria could be proven by means of TTP. Therefore justified chances result for treatment of wounds with TTP.

  4. Effects of ginseng on Pseudomonas aeruginosa motility and biofilm formation

    DEFF Research Database (Denmark)

    Wu, Hong; Lee, Baoleri; Yang, Liang;

    2011-01-01

    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 of...... P. aeruginosa at concentrations as low as 0.25%. Oral administration of ginseng extracts in mice promoted phagocytosis of P. aeruginosa PAO1 by airway phagocytes, but did not affect phagocytosis of a PAO1-filM mutant. Our study suggests that ginseng treatment may help to eradicate the biofilm...

  5. The implication of Pseudomonas aeruginosa biofilms in infections

    DEFF Research Database (Denmark)

    Rybtke, Morten Theil; Jensen, Peter Ø; Høiby, Niels; Givskov, Michael Christian; Tolker-Nielsen, Tim; Bjarnsholt, Thomas

    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 of...... 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. The...... immune response leading to this chronic inflammation is described. Finally, novel treatment strategies againstP. aeruginosa are described including, quorum-sensing inhibition and induced biofilm-dispersion. The tolerance towards currently available antimicrobials calls for development of alternative...

  6. 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.

  7. Whole genome and transcriptome analyses of environmental antibiotic sensitive and multi-resistant Pseudomonas aeruginosa isolates exposed to waste water and tap water

    OpenAIRE

    Schwartz, Thomas; Armant, Olivier; Bretschneider, Nancy; Hahn, Alexander; Kirchen, Silke; Seifert, Martin; Dötsch, Andreas

    2014-01-01

    The fitness of sensitive and resistant P seudomonas aeruginosa in different aquatic environments depends on genetic capacities and transcriptional regulation. Therefore, an antibiotic-sensitive isolate PA30 and a multi-resistant isolate PA49 originating from waste waters were compared via whole genome and transcriptome Illumina sequencing after exposure to municipal waste water and tap water. A number of different genomic islands (e.g. PAGIs, PAPIs) were identified in the two environmental is...

  8. Evaluation of ceftriaxone and other antibiotics against Escherichia coli, Pseudomonas aeruginosa, and Streptococcus pneumoniae under in vitro conditions simulating those of serious infections.

    OpenAIRE

    Satta, G; Cornaglia, G; Foddis, G; Pompei, R

    1988-01-01

    In pursuit of an in vitro system capable of reliably predicting the activities of antibiotics in serious infections and in infections occurring in immunocompromised hosts, we evaluated the abilities of four drugs to achieve virtually complete killing of bacterial cells growing in human body fluids in amounts which are very high and close to those likely to be present in serious infections; drug concentrations varied with time as they vary in human bronchial secretions or blood or urine (dynam...

  9. Colistin heteroresistance in Pseudomonas aeruginosa strains and their susceptibility to antibiotics used in combination%铜绿假单胞菌多黏菌素异质性耐药及联合药敏研究

    Institute of Scientific and Technical Information of China (English)

    许磊; 季京淑; 张慧川; 史可人; 王海萍; 王燕飞; 俞云松

    2015-01-01

    目的 明确多黏菌素(colistin)在多重耐药铜绿假单胞菌中的异质性及体外联合药敏情况.方法 选择297株碳青霉烯类耐药铜绿假单胞菌,采用微量肉汤稀释法测定多黏菌素等抗菌药物的最低抑菌浓度(MIC).采用群体谱分析方法分析多黏菌素敏感菌株的多黏菌素异质性,并分析部分菌株的杀菌曲线.采用棋盘法判断多黏菌素与亚胺培南、美罗培南、比阿培南、头孢他啶、左氧氟沙星、哌拉西林/他唑巴坦和头孢哌酮/舒巴坦的联合抑菌效应.结果 药物敏感性试验提示99.66%的菌株对多黏菌素敏感.群体谱分析提示异质性耐药菌株比例为35%(7/20株),具有异质性的菌株比例为20%(4/20株).联合药敏提示多黏菌素联合用药对异质性耐药菌株的作用以协同和相加为主,而对无异质性的菌株则主要表现为相加和无关作用.结论 多重耐药铜绿假单胞菌对多黏菌素的敏感性很高,但异质性及异质性耐药现象较为普遍.多黏菌素与其他多种抗菌药物联合对异质性耐药菌株的作用增强.%Objective To analyze the colistin heteroresistance in Pseudomonas aeruginosa strains and their in vitro susceptibility to antibiotics used in combination.Methods Two hundred and ninety-seven carbapenem-resistant Pseudomonas aeruginosa strains were selected for this study.Broth microdilution method was used to determine the minimum inhibitory concentrations of colistin and other antimicrobials against the Pseudomonas aeruginosa strains.The colistin heterogeneity of 20 colistin sensitive strains was analyzed by using population analysis profiles.The time-kill curves of 3 randomly selected colistin heteroresistant strains were used to determine the bacteriostatic activity of colistin.Chequer-board method was used to measure the combination efficacy of colistin with other antimicrobials including imipenem

  10. Preliminary crystallographic analysis of the antibiotic discharge outer membrane lipoprotein OprM of Pseudomonas aeruginosa with an exceptionally long unit cell and complex lattice structure.

    Science.gov (United States)

    Akama, Hiroyuki; Kanemaki, Misa; Tsukihara, Tomitake; Nakagawa, Atsushi; Nakae, Taiji

    2005-01-01

    Crystals of the drug-discharge outer membrane protein OprM (MW = 50.9 kDa) of the MexAB-OprM multidrug transporter of Pseudomonas aeruginosa have been grown at 293 K in the presence of 2-methyl-2,4-propanediol and a combination of surfactants. The crystal belonged to space group R32, with unit-cell parameters a = b = 85.43, c = 1044.3 A. Diffraction data for OprM were obtained using the undulator synchrotron-radiation beamline at SPring-8 (BL44XU, Osaka University), which allowed an extra-long specimen-to-detector distance with a wide detector area. The crystal diffracted to 2.56 A resolution using 0.9 A X-rays from the synchrotron-radiation source. A heavy-atom derivative for isomorphous replacement phasing was obtained using iridium chloride. PMID:16508113

  11. Antibiotic multiresistance analysis of mesophilic and psychrotrophic Pseudomonas spp. isolated from goat and lamb slaughterhouse surfaces throughout the meat production process.

    Science.gov (United States)

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

    2014-11-01

    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 ceftazidime (especially mesophiles), as well as colistin and tetracycline (especially psychrotrophes). However, they generally were sensitive to ciprofloxacin, gentamicin, imipenem, and kanamycin regardless of species identity. Worryingly, in the present study, we found multidrug resistance (MDR) to up to 13 antibiotics, which was related to intrinsic and acquired resistance mechanisms. Furthermore, a link between various antimicrobial resistance genes was shown for beta-lactams and tetracycline, trimethoprim, and sulfonamides. The distribution and resistome-based analysis of MDR pseudomonads in different slaughterhouse zones indicated that the main sources of the identical or related pseudomonad strains were the animals (feet and wool) and the slaughterhouse environment, being disseminated from the beginning, or entrance environment, to the environment of the finished meat products. Those facts must be taken into consideration to avoid cross-contamination with the subsequent flow of mobile resistance determinants throughout all slaughterhouse zones and then to humans and the environment by the application of adequate practices of hygiene and disinfection measures, including those for animal wool and feet and also the entrance environment. PMID:25172860

  12. Preliminary crystallographic analysis of the antibiotic discharge outer membrane lipoprotein OprM of Pseudomonas aeruginosa with an exceptionally long unit cell and complex lattice structure

    International Nuclear Information System (INIS)

    The OprM subunit of the MexAB-OprM efflux pump in P. aeruginosa is an outer membrane-anchored lipoprotein. OprM crystals have been grown at 293 K in the presence of 2-methyl-2,4-propanediol and a combination of surfactants and diffracted to 2.56 Å resolution. Crystals of the drug-discharge outer membrane protein OprM (MW = 50.9 kDa) of the MexAB-OprM multidrug transporter of Pseudomonas aeruginosa have been grown at 293 K in the presence of 2-methyl-2,4-propanediol and a combination of surfactants. The crystal belonged to space group R32, with unit-cell parameters a = b = 85.43, c = 1044.3 Å. Diffraction data for OprM were obtained using the undulator synchrotron-radiation beamline at SPring-8 (BL44XU, Osaka University), which allowed an extra-long specimen-to-detector distance with a wide detector area. The crystal diffracted to 2.56 Å resolution using 0.9 Å X-rays from the synchrotron-radiation source. A heavy-atom derivative for isomorphous replacement phasing was obtained using iridium chloride

  13. Preliminary crystallographic analysis of the antibiotic discharge outer membrane lipoprotein OprM of Pseudomonas aeruginosa with an exceptionally long unit cell and complex lattice structure

    Energy Technology Data Exchange (ETDEWEB)

    Akama, Hiroyuki; Kanemaki, Misa [Department of Molecular Life Science, Tokai University School of Medicine, Isehara 259-1193 (Japan); Tsukihara, Tomitake; Nakagawa, Atsushi [The Institute for Protein Research, Osaka University, Suita 565-0871 (Japan); Nakae, Taiji, E-mail: nakae@is.icc.u-tokai.ac.jp [Department of Molecular Life Science, Tokai University School of Medicine, Isehara 259-1193 (Japan)

    2005-01-01

    The OprM subunit of the MexAB-OprM efflux pump in P. aeruginosa is an outer membrane-anchored lipoprotein. OprM crystals have been grown at 293 K in the presence of 2-methyl-2,4-propanediol and a combination of surfactants and diffracted to 2.56 Å resolution. Crystals of the drug-discharge outer membrane protein OprM (MW = 50.9 kDa) of the MexAB-OprM multidrug transporter of Pseudomonas aeruginosa have been grown at 293 K in the presence of 2-methyl-2,4-propanediol and a combination of surfactants. The crystal belonged to space group R32, with unit-cell parameters a = b = 85.43, c = 1044.3 Å. Diffraction data for OprM were obtained using the undulator synchrotron-radiation beamline at SPring-8 (BL44XU, Osaka University), which allowed an extra-long specimen-to-detector distance with a wide detector area. The crystal diffracted to 2.56 Å resolution using 0.9 Å X-rays from the synchrotron-radiation source. A heavy-atom derivative for isomorphous replacement phasing was obtained using iridium chloride.

  14. Partial purification and characterization of the organic solvent-tolerant lipase produced by Pseudomonas fluorescens RB02-3 isolated from milk.

    Science.gov (United States)

    Boran, Rukiye; Ugur, Aysel

    2010-01-01

    Eighty-five putative Pseudomonas isolates were obtained from various raw milk and pasteurized milk samples using Pseudomonas CFC agar. Among them, 36 isolates were identified as Pseudomonas fluorescens, and one isolate was identified as Pseudomonas putida. Lipase activity of the strains was quantitatively measured by the spectrophotometric method using p-nitrophenyl palmitate (p-NPP) as substrate. Detected lipase activity of the strains was between 10.03 U/mL and 22.16 U/mL. Pseudomonas fluorescens RB02-3 possessed the highest lipase activity. The extracellular lipase of P. fluorescens RB02-3 strain was homogeneously purified using a combination of ammonium sulfate precipitation, dialysis, and gel filtration column chromatography. This purification procedure resulted in 2.97-fold purification with 20.3% recovery. The enzyme was characterized, and exhibited maximum activity at pH 7.0 and 50 °C; after it was incubated for 1 h it was activated in the presence of hexane, ethyl acetate, isopropanol, and ethanol and remained stable after the incubation was extended for 2 hr. The lipase was slightly inhibited in the presence of Zn²+, Co²+, Cu²+, Ni²+ salts, and ethylenediamine tetraacetic acid (EDTA), whereas Cd²+, sodium dodecyl sulfate (SDS), and Tween-80 had no effect on its activity. PMID:21108127

  15. [Survey of the antibiotic sensitivity of Pseudomonas aeruginosa in France and the distribution of beta-lactam resistance mechanisms: the GERPB 1999 study].

    Science.gov (United States)

    Cavallo, J D; Leblanc, F; Fabre, R; Fourticq-Esqueöute, A

    2001-09-01

    A prospective survey was carried out in october 1999 in 15 french teaching hospitals. Average susceptibility rates, determined by minimal inhibitory concentrations, for the 738 non-repetitive strains of P. aeruginosa isolated were: ticarcillin, 58%, ticarcillin + clavulanic acid, 56%, piperacillin, 73%, piperacillin + tazobactam, 82%, ceftazidime, 76%, cefepime, 53%, cefpirome, 36%, aztreonam, 58%, imipenem, 81%, amikacin, 62%, tobramycine, 71% and, ciprofloxacin, 60%. Among the 75% serotypable strains, the most frequent serotypes were: O:6 (15.3%), O:11 (14.5%), O:1 (10.4%), O:3 (7.9%), O:4 (6.1%) and O:12 (6.1%). The serotype O:12 was the most resistant to antibiotics. Forty-two percent of the strains were resistant or presented an intermediate susceptibility to ticarcillin. Mechanisms were as follow: 14.5% non enzymatic mechanism, 12.5% overproduction of the constitutive cephalosporinase, 7.1% transferable betalactamase and, 6.9% combination of these mechanisms. Among the 67 transferable betalactamases: 48 (71.6%) were PSE-1, 12 (19.4%) TEM-2 and 6 (7.5%) oxacillinases. One extended spectrum betalactamase was characterized. Among the cephalosporines tested, cefepime was less affected by the overproduction of constitutive cephalosporinase. Ceftazidime, remained the best cephalosporin except against the strains overexpressing the chromosomal type 1 beta-lactamase. Resistance to tobramycin was mainly due to enzymatic mechanisms with a high level of resistance. Decreased susceptibility was more frequent for amikacin than for tobramycin. This was probably related with non enzymatic mechanisms. PMID:11642015

  16. Study on β-lactam Antibiotic Resistant Genes in Pseudomonas Aeruginosa Strain%铜绿假单胞菌β-内酰胺类抗菌药物耐药相关基因研究

    Institute of Scientific and Technical Information of China (English)

    吕军; 杨宏伟; 曹峰; 张吉才; 朱名安

    2011-01-01

    Objective To investigate the p-lactam antibiotic resistant phenotype and genetypes of Pseudomonas aeruginosa (Pae) in Shiyan district. Methods The senior expert system of VITEK 2 Compact was used to judge the p-lactamase drug resistant phenotypes in 896 strains Pae from January to September in 2011. Total 13 kinds of p-lactamase genes were detected by PCR in the consecutively separated 25 strains Pae from July to September. Results There were 8 species of p-lactam antibiotic resistant phenotypes in 896 strains and 4 species in 25 strains, in which the main phenotype was high level R + R Carbapenems(IMPER) and accounted for 47% and 48% ,respectively. The positive p-lactamase genes were bla OXA-10, blaDHA.bla SHV.bla CARB.bla GIM,bla GES,bla TEM,and the positive rates were 4% ,4% ,20% ,12% ,8% ,8% , 16% ,respectively,and the lacking rate of bla oprD2 gene was 60%. No bla IMP,bla VIM,bla PER,bla VEB and bla SPM genes were detected. Conclusion The p-lactam antibiotic resistant of Pae were correlated with the genes of bla OXA-10, bla DHA,bla SHV,bla CARB,bla GIM,bla GES,bla TEM and oprD2 gene lacking,which were the main reasons for p-lactam antibiotic resistance in Shiyan district.%目的:了解十堰地区铜绿假单胞菌β-内酰胺类药物的耐药表型和基因分布情况,并探讨基因型与表型的相关性.方法:用VITEK 2 Compact高级专家系统判定2011年1~9月分离的896株铜绿假单胞菌对β-内酰胺类药物的耐药表型,用PCR检测25株铜绿假单胞菌的13种β-内酰胺酶基因.结果:896株铜绿假单胞菌对β-内酰胺酶类药物的耐药表型有9种,连续分离的25株铜绿假单胞菌中耐药表型有4种,主要表型均为高水平耐药+碳青霉烯酶(不渗透性),分别占47%和48%.检出阳性的8种耐药基因包括bla OXA-10、bla DHA、bla SHV、bla CARB、bla GIM、bla GES、bla TEM,阳性率分别为4%、4%、20%、12%、8%、8%、16%,另bla oprD2基因缺失率为60%,未检出bla IMP

  17. Antibiotic resistance pattern in uropathogens

    OpenAIRE

    Gupta V; Yadav A; Joshi R

    2002-01-01

    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 urina...

  18. 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?

  19. 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...

  20. Alginate Production by Pseudomonas putida Creates a Hydrated Microenvironment and Contributes to Biofilm Architecture and Stress Tolerance under Water-Limiting Conditions▿

    OpenAIRE

    Chang, Woo-Suk; van de Mortel, Martijn; Nielsen, Lindsey; Nino de Guzman, Gabriela; Li, Xiaohong; Halverson, Larry J.

    2007-01-01

    Biofilms exist in a variety of habitats that are routinely or periodically not saturated with water, and residents must integrate cues on water abundance (matric stress) or osmolarity (solute stress) into lifestyle strategies. Here we examine this hypothesis by assessing the extent to which alginate production by Pseudomonas putida strain mt-2 and by other fluorescent pseudomonads occurs in response to water limitations and how the presence of alginate in turn influences biofilm development a...

  1. Antibiotics Quiz

    Science.gov (United States)

    ... Recommendations Pediatric Treatment Recommendations Inpatient Healthcare Professionals Community Pharmacists Continuing Education & Curriculum Opportunities Weighing in on Antibiotic Resistance Improving Prescribing Outpatient Antibiotic Stewardship Interventions That Work Systematic Reviews ...

  2. [Vasculitis caused by Pseudomonas: a case report].

    Science.gov (United States)

    Escamilla, Y; Gutiérrez, M; Martínez, T; Bodoque, M; Gómez, J M; Moreno, A

    1996-01-01

    Pseudomona vasculitis is an exceptional disease. Only a few cases have been reported, non with oropharyngeal involvement. The case of a 30-year-old, HIV-positive man who suddenly developed septicemia and necrotizing lesions with tissue destruction of the oropharynx is reported. Histological study confirmed vasculitis. Pseudomona aeruginosa was isolated in peripheral blood and in the biopsy of the palatal lesion. Antibiotic treatment produced satisfactory results. PMID:8991411

  3. Impact of Pseudomonas aeruginosa quorum sensing on biofilm persistence in an in vivo intraperitoneal foreign-body infection model

    DEFF Research Database (Denmark)

    Christensen, Louise D; Moser, Claus; Jensen, Peter Ø; Rasmussen, Thomas B; Christophersen, Lars; Kjelleberg, Staffan; Kumar, Naresh; Høiby, Niels; Givskov, Michael Christian; Bjarnsholt, Thomas

    Pseudomonas aeruginosa is an opportunistic human pathogen that causes chronic biofilm-based infections in host organisms. P. aeruginosa employs quorum sensing (QS) to control expression of its virulence, and to establish and maintain chronic infections. Under such conditions, the biofilm mode of...... growth contributes significantly to P. aeruginosa tolerance to the action of the innate and adaptive defence system and numerous antibiotics. In the present study, an in vivo foreign-body infection model was established in the peritoneal cavity of mice. Experimental data showed that QS-deficient P...

  4. Antibiotic Resistance

    Science.gov (United States)

    Antibiotics are medicines that fight bacterial infections. Used properly, they can save lives. But there is a growing problem of antibiotic resistance. It happens when bacteria change and become able to resist the effects of an antibiotic. Using antibiotics can lead to resistance. ...

  5. Alginate overproduction affects Pseudomonas aeruginosa biofilm structure and function

    DEFF Research Database (Denmark)

    Hentzer, Morten; Teitzel, G.M.; Balzer, G.J.;

    2001-01-01

    During the course of chronic cystic fibrosis (CF) infections, Pseudomonas aeruginosa undergoes a conversion to a mucoid phenotype, which is characterized by overproduction of the exopolysaccharide alginate. Chronic P. aeruginosa infections involve surface-attached, highly antibiotic-resistant com......During the course of chronic cystic fibrosis (CF) infections, Pseudomonas aeruginosa undergoes a conversion to a mucoid phenotype, which is characterized by overproduction of the exopolysaccharide alginate. Chronic P. aeruginosa infections involve surface-attached, highly antibiotic...

  6. 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...

  7. Polylactide-polyglycolide antibiotic implants.

    Science.gov (United States)

    Garvin, Kevin; Feschuk, Connie

    2005-08-01

    Surgeons continually struggle to reduce orthopaedic infections, but no current treatment offers minimum side effects with maximum effectiveness. Antibiotics mixed in plaster of paris have been successful in treating large bony defects in patients with chronic osteomyelitis, and have the advantage of being well tolerated and absorbed by the body. Antibiotics impregnated in polymethylmethacrylate (PMMA) have offered local antibiotic delivery with some success. However, the effect of the antibiotic on the bone cement, the inconsistent elution of the antibiotic, and the need to remove the PMMA implant drives the need for a better system of antibiotic delivery. Polymers or copolymers of antibiotic-impregnated polylactic acid, polyglycolic acid or polyparadioxanone may provide an absorbable system for localized antibiotic delivery. Similar biodegradable systems used to treat small bone fractures have been successful with minimal side effects. In vitro studies have shown promising results of antibiotic elution from bioabsorbable microspheres and beads. Animal in vivo tests have shown that antibiotic impregnated polymers can successfully treat induced osteomyelitis in rabbits and dogs. These studies have provided consistent reproducible results, and now it is time to plan human trials to assess the efficacy of antibiotic microspheres implanted in infected bone and to plan in vivo and in vitro animal testing to investigate the feasibility of antibiotic-polymer-coated components. PMID:16056034

  8. 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

  9. Draft Genome Sequence of Pseudomonas Strain P818, Isolated from Glyphosate-Polluted Soil

    OpenAIRE

    Cao, Gaoyi; Liu, Yunjun; Liu, Guiming; Wang, Jianhua; Wang, Guoying

    2013-01-01

    Pseudomonas strain P818 was isolated from glyphosate-polluted soil in China. This bacterium presents a capacity for high glyphosate tolerance. We present the draft genome sequence of the strain Pseudomonas P818. The genes involved in the glyphosate tolerance were identified. This genomic information will facilitate the study of glyphosate tolerance mechanisms.

  10. A cold-adapted and organic solvent-tolerant lipase from a psychrotrophic bacterium Pseudomonas sp. strain YY31: identification, cloning, and characterization.

    Science.gov (United States)

    Yamashiro, Yoko; Sakatoku, Akihiro; Tanaka, Daisuke; Nakamura, Shogo

    2013-10-01

    A novel cold-adapted lipase (designated as LipYY31) was obtained from a psychrotrophic Pseudomonas sp. YY31. The strain YY31 was gram-negative, rod shaped, motile by means of one polar flagellum, and exhibited chemotaxis toward oil droplets under a microscope. The strain displayed remarkable degradation of edible oil and fat even at 5 °C. The LipYY31 DNA fragment contains an open reading frame of 1,410 bp which encoded a protein of 470 amino acids with an estimated molecular mass of 49,584 Da. LipYY31 showed high sequence similarity to those of subfamily Ι.3 lipase and had a conserved GXSXG motif around the catalytic Ser residue. Its optimal temperature was 25-30 °C, and it retained 20-40 % of its activity at 0-5 °C. The optimal pH value was 8.0. The activity was strongly inhibited by Cd(2+), Zn(2+), EDTA and was highly dependent on Ca(2+). Tricaprin and p-nitrophenyl caprate were the most favorable substrates among the triglycerides and p-nitrophenyl esters, respectively. LipYY31 also had high activity towards natural substrates including edible vegetable oils and animal fat. Furthermore, LipYY31 was very active and stable in the presence of several detergents and organic solvents. In particular, the lipase exhibited high stability against organic solvents such as methanol, ethanol, and isopropanol. PMID:23918082

  11. 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 a...... QS inhibitor.We randomized 34 patients to garlic or olive oil capsules (both 656 mg daily). Clinical outcomes and safety bloods were measured at baseline and after 8 weeks treatment. In this exploratory study, analysis was per protocol.Eight patients withdrew, leaving 26 for analysis (13 garlic...... the garlic group, seven patients had IV antibiotics versus five placebo. There was a highly significant correlation between plasma and sputum measurements of the QS molecule 3-oxo-C12-HSL (Pearson correlation coefficient = 0.914, P = 0.004). At the end of treatment five patients in each group had...

  12. 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 en...... the wild type phenotype. The results reported here suggest that the SCV of L. monocytogenes could be of clinical importance and highlight a need for adequate clinical screening for this phenotype, as it could affect antibiotic treatment outcomes....... 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...

  13. Fosfomycin Enhances the Active Transport of Tobramycin in Pseudomonas aeruginosa

    OpenAIRE

    MacLeod, David L.; Velayudhan, Jyoti; Kenney, Thomas F.; Therrien, Joseph H.; Sutherland, Jennifer L.; Barker, Lynn M.; Baker, William R.

    2012-01-01

    Elevated levels of mucins present in bronchiectatic airways predispose patients to bacterial infections and reduce the effectiveness of antibiotic therapies by directly inactivating antibiotics. Consequently, new antibiotics that are not inhibited by mucins are needed to treat chronic respiratory infections caused by Pseudomonas aeruginosa and Staphylococcus aureus. In these studies, we demonstrate that fosfomycin synergistically enhances the activity of tobramycin in the presence of mucin. T...

  14. Comparative proteomic analysis of a potentially probiotic Lactobacillus pentosus MP-10 for the identification of key proteins involved in antibiotic resistance and biocide tolerance.

    Science.gov (United States)

    Casado Muñoz, María del Carmen; Benomar, Nabil; Ennahar, Saïd; Horvatovich, Peter; Lavilla Lerma, Leyre; Knapp, Charles W; Gálvez, Antonio; Abriouel, Hikmate

    2016-04-01

    Probiotic bacterial cultures require resistance mechanisms to avoid stress-related responses under challenging environmental conditions; however, understanding these traits is required to discern their utility in fermentative food preparations, versus clinical and agricultural risk. Here, we compared the proteomic responses of Lactobacillus pentosus MP-10, a potentially probiotic lactic acid bacteria isolated from brines of naturally fermented Aloreña green table olives, exposed to sub-lethal concentrations of antibiotics (amoxicillin, chloramphenicol and tetracycline) and biocides (benzalkonium chloride and triclosan). Several genes became differentially expressed depending on antimicrobial exposure, such as the up-regulation of protein synthesis, and the down-regulation of carbohydrate metabolism and energy production. The antimicrobials appeared to have altered Lb. pentosus MP-10 physiology to achieve a gain of cellular energy for survival. For example, biocide-adapted Lb. pentosus MP-10 exhibited a down-regulated phosphocarrier protein HPr and an unexpressed oxidoreductase. However, protein synthesis was over-expressed in antibiotic- and biocide-adapted cells (ribosomal proteins and glutamyl-tRNA synthetase), possibly to compensate for damaged proteins targeted by antimicrobials. Furthermore, stress proteins, such as NADH peroxidase (Npx) and a small heat shock protein, were only over-expressed in antibiotic-adapted Lb. pentosus MP-10. Results showed that adaptation to sub-lethal concentrations of antimicrobials could be a good way to achieve desirable robustness of the probiotic Lb. pentosus MP-10 to various environmental and gastrointestinal conditions (e.g., acid and bile stresses). PMID:26827291

  15. 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

    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...

  16. Intensive Care Unit Infections and Antibiotic Use

    OpenAIRE

    Ayşegül Yeşilkaya; Hande Arslan

    2011-01-01

    Burn wound infections is the leading cause of morbidity and mortality in burn trauma patients. Although burn wound is sterile at the beginning, because of risk factors such as prolonged hospital stay, immunesuppression and burn affecting large body surface area, colonisation firstly with Staphylococcus aureus and then Pseudomonas aeruginosa will occur later. Delay in wound closure and treatment with broad-spectrum antibiotic will result wound colonisation with antibiotic-resistant bacteria. T...

  17. Optimization studies on production of a salt-tolerant protease from Pseudomonas aeruginosa strain BC1 and its application on tannery saline wastewater treatment

    Directory of Open Access Journals (Sweden)

    Senthilkumar Sivaprakasam

    2011-12-01

    Full Text Available Treatment and safe disposal of tannery saline wastewater, a primary effluent stream that is generated by soaking salt-laden hides and skin is one of the major problems faced by the leather manufacturing industries. Conventional treatment methods like solar evaporation ponds and land composting are not eco-friendly as they deteriorate the ground water quality. Though, this waste stream is comprised of high concentration of dissolved proteins the presence of high salinity (1-6 % NaCl by wt makes it non-biodegradable. Enzymatic treatment is one of the positive alternatives for management of such kind of waste streams. A novel salt-tolerant alkaline protease obtained from P.aeruginosa (isolated from tannery saline wastewater was used for enzymatic degradation studies. The effect of various physical factors including pH, temperature, incubation time, protein source and salinity on the activity of identified protease were investigated. Kinetic parameters (Km , Vmax were calculated for the identified alkaline protease at varying substrate concentrations. Tannery saline wastewater treated with identified salt tolerant protease showed 75 % protein removal at 6 h duration and 2 % (v/v protease addition was found to be the optimum dosage value.

  18. Tolerance to the antimicrobial peptide colistin in Pseudomonas aeruginosa biofilms is linked to metabolically active cells, and depends on the pmr and mexAB-oprM genes

    DEFF Research Database (Denmark)

    Pamp, Sünje Johanna; Gjermansen, Morten; Johansen, Helle Krogh;

    2008-01-01

    antimicrobial peptide colistin. On the contrary, biofilm cells exhibiting low metabolic activity were killed by colistin. We demonstrate that the subpopulation of metabolically active cells is able to adapt to colistin by inducing a specific adaptation mechanism mediated by the pmr operon, as well as an...... unspecific adaptation mechanism mediated by the mexAB-oprM genes. Mutants defective in either pmr-mediated lipopolysaccharide modification or in mexAB-oprM-mediated antimicrobial efflux were not able to develop a tolerant subpopulation in biofilms. In contrast to the observed pattern of colistin...... physiologically distinct subpopulations by combined antimicrobial treatment with either ciprofloxacin and colistin or tetracycline and colistin almost completely eradicated all biofilm cells....

  19. 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...

  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

    tolerant of 20mM H2O2 as compared to the wild type, with 6.3 log10 CFU/ml and 3.7 log10 CFU/ml, respectively. The SCV E18 had lower survival rate in unactivated macrophages, however, it was able to survive and multiply to almost 100-fold higher CFU/ml than the wild type in CaCo-2 epithelial cells...

  1. 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...

  2. Cross-Resistance between Triclosan and Antibiotics in Pseudomonas aeruginosa Is Mediated by Multidrug Efflux Pumps: Exposure of a Susceptible Mutant Strain to Triclosan Selects nfxB Mutants Overexpressing MexCD-OprJ

    OpenAIRE

    Chuanchuen, Rungtip; Beinlich, Kerry; Hoang, Tung T.; Becher, Anna; Karkhoff-Schweizer, Roxann R.; Schweizer, Herbert P.

    2001-01-01

    Triclosan is an antiseptic frequently added to items as diverse as soaps, lotions, toothpaste, and many commonly used household fabrics and plastics. Although wild-type Pseudomonas aeruginosa expresses the triclosan target enoyl-acyl carrier protein reductase, it is triclosan resistant due to expression of the MexAB-OprM efflux system. Exposure of a susceptible Δ(mexAB-oprM) strain to triclosan selected multidrug-resistant bacteria at high frequencies. These bacteria hyperexpressed the MexCD-...

  3. Mannitol Does Not Enhance Tobramycin Killing of Pseudomonas aeruginosa in a Cystic Fibrosis Model System of Biofilm Formation.

    Directory of Open Access Journals (Sweden)

    Katherine E Price

    Full Text Available Cystic Fibrosis (CF is a human genetic disease that results in the accumulation of thick, sticky mucus in the airways, which results in chronic, life-long bacterial biofilm infections that are difficult to clear with antibiotics. Pseudomonas aeruginosa lung infection is correlated with worsening lung disease and P. aeruginosa transitions to an antibiotic tolerant state during chronic infections. Tobramycin is an aminoglycoside currently used to combat lung infections in individuals with CF. While tobramycin is effective at eradicating P. aeruginosa in the airways of young patients, it is unable to completely clear the chronic P. aeruginosa infections in older patients. A recent report showed that co-addition of tobramycin and mannitol enhanced killing of P. aeruginosa grown in vitro as a biofilm on an abiotic surface. Here we employed a model system of bacterial biofilms formed on the surface of CF-derived airway cells to determine if mannitol would enhance the antibacterial activity of tobramycin against P. aeruginosa grown on a more clinically relevant surface. Using this model system, which allows the growth of robust biofilms with high-level antibiotic tolerance analogous to in vivo biofilms, we were unable to find evidence for enhanced antibacterial activity of tobramycin with the addition of mannitol, supporting the observation that this type of co-treatment failed to reduce the P. aeruginosa bacterial load in a clinical setting.

  4. Forgotten antibiotics

    DEFF Research Database (Denmark)

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

    2012-01-01

    disease specialists in Europe, the United States, Canada, and Australia. An international expert panel selected systemic antibacterial drugs for their potential to treat infections caused by resistant bacteria or their unique value for specific criteria. Twenty-two of the 33 selected antibiotics were...... available in fewer than 20 of 38 countries. Economic motives were the major cause for discontinuation of marketing of these antibiotics. Fourteen of 33 antibiotics are potentially active against either resistant Gram-positive or Gram-negative bacteria. Urgent measures are then needed to ensure better...

  5. Small Rna Regulatory Networks In Pseudomonas Putida

    DEFF Research Database (Denmark)

    Bojanovic, Klara; Long, Katherine

    2015-01-01

    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...

  6. Antibiotic and heavy metal resistance in motile aeromonads and pseudomonads from rainbow trout (Oncorhynchus mykiss) farms in Australia.

    Science.gov (United States)

    Akinbowale, Olasumbo L; Peng, Haihong; Grant, Peter; Barton, Mary D

    2007-08-01

    A total of 129 Pseudomonas spp. and 90 Aeromonas spp. were isolated from nine rainbow trout (Oncorhynchus mykiss) farms in Australia. All the isolates were tested for sensitivity to 15 antibiotics and the multiresistant strains were tested for sensitivity to seven heavy metals. Minimal inhibitory concentrations (MICs) were determined by the agar dilution method. In Pseudomonas spp., resistance to amoxicillin, cefalothin, ceftiofur, ticarcillin, chloramphenicol, florfenicol, streptomycin, nitrofurantoin and trimethoprim was widespread, whereas resistance to cefotaxime and oxolinic acid was less common and only single isolates were resistant to tetracycline and sulfamethoxazole; all isolates were sensitive to ciprofloxacin and gentamicin. In Aeromonas spp., resistance to amoxicillin and cefalothin was widespread, resistance to ticarcillin, tetracycline and streptomycin was common, whilst resistance to ceftiofur, florfenicol and sulfamethoxazole was less common. Single isolates were resistant to chloramphenicol, nitrofurantoin and trimethoprim, and all isolates were sensitive to cefotaxime, oxolinic acid, ciprofloxacin and gentamicin. Multiple resistance was also observed. Most isolates were tolerant to different concentrations of various heavy metals, as evidenced by their MICs ranging from 6.25 microg/mL to >3200 microg/mL. These results confirm our previous findings that bacteria resistant to antibiotics are present in fish and sediments from aquaculture in Australia. In addition, we have found resistance to heavy metals in fish and sediment isolates. Much of the antibiotic resistance detected is likely to be intrinsic, although resistance to oxytetracycline, streptomycin and sulfonamides suggests either contamination from run-off from farms or perhaps off-label use of antibiotics in a situation where no antibiotics are licensed for use in aquaculture. PMID:17524624

  7. Antibiotic Resistance

    Science.gov (United States)

    ... Radiation-Emitting Products Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products For Consumers Home For Consumers Consumer Information by Audience For Women Antibiotic Resistance Share Tweet Linkedin Pin it More ...

  8. Flavonoids from Rhizophora conjugata fruit extract blocks virulence factors of Pseudomonas aeruginosa

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, D.; Tilvi, S.; DeSouza, L.

    Pseudomonas aeruginosa is a major nosocomial pathogen which causes hospital acquired infections and recently has gained importance as a model to study antibiotic resistance. In the present study, we investigated the effect of methanol and methanol...

  9. Effect of Pseudomonas aeruginosa Pure Exotoxin A on Mice WBC in Comparison with Human WBC Contaminated by Pseudomonas aeruginosa

    OpenAIRE

    M Naghmachi; A Sharifi; J Kohanteb

    2008-01-01

    ABSTRACT Introduction & Objective: Pseudomonas aeruginosa is a gram negative bacterial. This bacterium is resistant to many antibiotics and chemical disinfectants. Pseudomonas aeruginosa is an opportunistic bacteria and caused infection in skin, external ear, upper respiratory tract, large intestine and is an important bacteria in nosocomial infections. It causes acute infection in burn disease. This bacterium can produce exotoxin A and effect on elongation factor II and can stop protein ...

  10. 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

    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.

  11. 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...... to antibiotics. Biofilm growth is associated with an increased level of mutations as well as with quorum-sensing-regulated mechanisms. Conventional resistance mechanisms such as chromosomal beta-lactamase, upregulated efflux pumps and mutations in antibiotic target molecules in bacteria also contribute...... to the survival of biofilms. Biofilms can be prevented by early aggressive antibiotic prophylaxis or therapy and they can be treated by chronic suppressive therapy. A promising strategy may be the use of enzymes that can dissolve the biofilm matrix (e.g. DNase and alginate lyase) as well as quorum...

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

    OpenAIRE

    Freschi, Luca; Jeukens, Julie; Kukavica-Ibrulj, Irena; Boyle, Brian; Dupont, Marie-Josée; Laroche, Jérôme; Larose, Stéphane; Maaroufi, Halim; Fothergill, Joanne L.; Moore, Matthew; Winsor, Geoffrey L.; Shawn D Aaron; Barbeau, Jean; Bell, Scott C.; Burns, Jane L.

    2015-01-01

    The International Pseudomonas aeruginosa Consortium is sequencing over 1000 genomes and building an analysis pipeline for the study of Pseudomonas genome evolution, antibiotic resistance and virulence genes. Metadata, including genomic and phenotypic data for each isolate of the collection, are available through the International Pseudomonas Consortium Database (http://ipcd.ibis.ulaval.ca/). Here, we present our strategy and the results that emerged from the analysis of the first 389 genomes....

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

    OpenAIRE

    Luca eFreschi; Julie eJeukens; Irena eKukavica-Ibrulj; Brian eBoyle; Marie-Josée eDupont; Jérôme eLaroche; Stéphane eLarose; Halim eMaaroufi; Fothergill, Joanne L.; Matthew eMoore; Winsor, Geoffrey L.; Shawn D Aaron; Jean eBarbeau; Bell, Scott C.; Burns, Jane L.

    2015-01-01

    The International Pseudomonas aeruginosa Consortium is sequencing over 1000 genomes and building an analysis pipeline for the study of Pseudomonas genome evolution, antibiotic resistance and virulence genes. Metadata, including genomic and phenotypic data for each isolate of the collection, are available through the International Pseudomonas Consortium Database (http://ipcd.ibis.ulaval.ca/). Here, we present our strategy and the results that emerged from the analysis of the first 389 genomes....

  14. Study of Pseudomonas Aeroginosa resistance to Penicillines, Cephalosporins and Aminoglycosides

    Directory of Open Access Journals (Sweden)

    Maleknezhad P

    1998-07-01

    Full Text Available Drug therapy and prophylaxy in infectious diseases, from hygienic and economical point of view, are very important. Infections caused by pseudomonas aeroginosa were particularly severe, with high mortality rates. In the recent years pseudomonas aeroginosa continued to cause the most severe, life-thereating infections in burned patients, in spite of the introduction of a wide variety of antibiotics advised specifically for their anti pseudomonal activity. The aim of this study, in which many cases of ps.aeroginosa infections are assessed is to identify the drug resistance of this bacteria to penicillines, cephalosporins and aminoglycosides by antibiotic sensitivity test (disk ager diffusion. Results as percent of resistance to each antibiotic were 89% to carbenicillin, 55% to piperacillin, 89% to mezlocillin, 89.5% to ticarcillin+clavulonic acid, 85% to ceftriaxone, 95% to tobramycin, 5% of all isolates were not sensitive to any antibiotics.

  15. 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...

  16. Analysis of antibiotic consumption in burn patients.

    Science.gov (United States)

    Soleymanzadeh-Moghadam, Somayeh; Azimi, Leila; Amani, Laleh; Rastegar Lari, Aida; Alinejad, Faranak; Rastegar Lari, Abdolaziz

    2015-01-01

    Infection control is very important in burn care units, because burn wound infection is one of the main causes of morbidity and mortality among burn patients. Thus, the appropriate prescription of antibiotics can be helpful, but unreasonable prescription can have detrimental consequences, including greater expenses to patients and community alike. The aim of this study was to determine the effect of antibiotic therapy on the emergence of antibiotic-resistant bacteria. 525 strains of Pseudomonas aeruginosa, Acinetobacter baumannii and Staphylococcus aureus were isolated from 335 hospitalized burn patients. Antibiotic susceptibility tests were performed after identification the strains. The records of patients were audited to find the antibiotic used. The results indicated that P. aeruginosa is the most prevalent Gram-negative bacteria. Further, it showed a relation between abuse of antibiotics and emergence of antibiotic resistance. Control of resistance to antibiotics by appropriate prescription practices not only facilitates prevention of infection caused by multi-drug resistant (MDR) microorganisms, but it can also decrease the cost of treatment. PMID:26124986

  17. 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

  18. Phloroglucinol functions as an intracellular and intercellular chemical messenger influencing gene expression in Pseudomonas protegens

    Science.gov (United States)

    Bacteria can be both highly communicative and highly competitive in natural habitats and antibiotics are thought to play a role in both of these processes. The soil bacterium Pseudomonas protegens Pf-5 produces a spectrum of antibiotics, two of which, pyoluteorin and 2,4-diacetylphloroglucinol (DAP...

  19. Antibiotic Resistance Patterns of Gram-Negative Psychrotrophic Bacteria from Bulk Tank Milk.

    Science.gov (United States)

    Decimo, Marilù; Silvetti, Tiziana; Brasca, Milena

    2016-04-01

    Bacterial resistance to antibiotics is a major global health problem and resistance of Pseudomonadaceae and Enterobacteriaceae is a serious concern. We investigated the prevalence of drug-resistance in a total of 80 psychrotrophic strains from bulk milk belonging to Pseudomonas genus (n. 63) and Enterobacteriaceae group (n. 17). All the strains were tested against 16 antibiotics. Pseudomonas were further investigated for their sensitivity against 12 additional antibiotics. Pseudomonas showed a high susceptibility toward fluoroquinolones, aminoglycosides, and piperacillin and, to a lesser extent, to imipenem, ceftazidime, cefepime. Thirty-five out of 63 Pseudomonas strains were susceptible to meropenem, while among antibiotics for which recommended breakpoints are not yet available, 55% of Pseudomonas strains had no inhibition halo in presence of nitrofurantoin, highlighting a resistance toward this drug. The results obtained in this study indicate a high efficiency of fluoroquinolones, chloramphenicol (94%), and kanamycin (76%) for Enterobacteriaceae while a high prevalence of resistant strains was found to ampicillin (13/17). Serratia marcescens is highly susceptible to fluoroquinolones, chloramphenicol, and kanamycin. Moreover, mupirocin seems to be the new antibiotic with the less efficacy for Enterobacteriaceae, with 41% of strains without halo, pointing out an important resistance. Further knowledge on resistance to known and new antibiotics among Pseudomonas species and Enterobacteriaceae of milk origin was acquired. PMID:26910385

  20. 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 of...

  1. BIOGEOGRAPHY OF 2,4-DIACETYLPHLOROGLUCINOL-PRODUCING PSEUDOMONAS FLUORESCENS.

    Science.gov (United States)

    Strains of Pseudomonas fluorescens producing the antibiotic 2,4-diacetylphloroglucinol (phlD+) are biocontrol agents of soilborne pathogens and play a key role in the disease suppressiveness of some soils. Considerable variation among isolates has been observed by using genomic fingerprinting techn...

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

    Science.gov (United States)

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

    2012-01-01

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

  3. Antimicrobial Resistance and Molecular Typing of Pseudomonas Aeruginosa Isolated from Surgical Wounds in Lagos, Nigeria

    Directory of Open Access Journals (Sweden)

    Kehinde Akinsinde

    2012-06-01

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

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

    Institute of Scientific and Technical Information of China (English)

    NING Fang-gang; ZHAO Xiao-zhuo; BIAN Jing; ZHANG Guo-an

    2011-01-01

    Background 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.Methods 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.Results Four patients recovered from bums and one died after therapy.Conclusions First, compromised immunity caused by delayed healing of burn wounds in patients with large-area bums 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.

  5. Impact of Pseudomonas aeruginosa quorum sensing on biofilm persistence in an in vivo intraperitoneal foreign-body infection model

    DEFF Research Database (Denmark)

    Christensen, Louise Dahl; Moser, Claus; Jensen, Peter Ø;

    2007-01-01

    growth contributes significantly to P. aeruginosa tolerance to the action of the innate and adaptive defence system and numerous antibiotics. In the present study, an in vivo foreign-body infection model was established in the peritoneal cavity of mice. Experimental data showed that QS-deficient P......Pseudomonas aeruginosa is an opportunistic human pathogen that causes chronic biofilm-based infections in host organisms. P. aeruginosa employs quorum sensing (QS) to control expression of its virulence, and to establish and maintain chronic infections. Under such conditions, the biofilm mode of...... the placebo-treated group. These results were obtained with both an inbred (BALB/c) and an outbred (NMRI) mouse strain. The present results support a model by which functional QS systems play a pivotal role in the ability of bacteria to resist clearing by the innate immune system and strongly suggest...

  6. 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...

  7. Coexistence of Antibiotic-Producing and Antibiotic-Sensitive Bacteria in Biofilms Is Mediated by Resistant Bacteria▿ †

    OpenAIRE

    Narisawa, Naoki; Haruta, Shin; Arai, Hiroyuki; Ishii, Masaharu; Igarashi, Yasuo

    2008-01-01

    Antibiotic-sensitive bacteria have been found to coexist with antibiotic-producing bacteria in biofilms, but little is known about how the former develop in such an environment. Here we isolated pyocyanin-sensitive bacteria belonging to the genus Brevibacillus from a biofilm derived from soil extract and based on the preestablished biofilm of a pyocyanin producer, Pseudomonas aeruginosa strain P1. In addition, pyocyanin-resistant strains belonging to the genus Raoultella were isolated from th...

  8. Alginate overproduction affects Pseudomonas aeruginosa biofilm structure and function

    DEFF Research Database (Denmark)

    Hentzer, Morten; Teitzel, G.M.; Balzer, G.J.; Heydorn, Arne; Molin, Søren; Givskov, Michael Christian; Parsek, M.R.

    2001-01-01

    During the course of chronic cystic fibrosis (CF) infections, Pseudomonas aeruginosa undergoes a conversion to a mucoid phenotype, which is characterized by overproduction of the exopolysaccharide alginate. Chronic P. aeruginosa infections involve surface-attached, highly antibiotic-resistant com......During the course of chronic cystic fibrosis (CF) infections, Pseudomonas aeruginosa undergoes a conversion to a mucoid phenotype, which is characterized by overproduction of the exopolysaccharide alginate. Chronic P. aeruginosa infections involve surface-attached, highly antibiotic...... abiotic surface. Biofilms formed by an alginate- overproducing strain exhibit a highly structured architecture and are significantly more resistant to the antibiotic tobramycin than a biofilm formed by an isogenic nonmucoid strain. These results suggest that an important consequence of the conversion to...... mucoidy is an altered biofilm architecture that shows increasing resistance to antimicrobial treatments....

  9. Persistence and resistance as complementary bacterial adaptations to antibiotics.

    Science.gov (United States)

    Vogwill, T; Comfort, A C; Furió, V; MacLean, R C

    2016-06-01

    Bacterial persistence represents a simple of phenotypic heterogeneity, whereby a proportion of cells in an isogenic bacterial population can survive exposure to lethal stresses such as antibiotics. In contrast, genetically based antibiotic resistance allows for continued growth in the presence of antibiotics. It is unclear, however, whether resistance and persistence are complementary or alternative evolutionary adaptations to antibiotics. Here, we investigate the co-evolution of resistance and persistence across the genus Pseudomonas using comparative methods that correct for phylogenetic nonindependence. We find that strains of Pseudomonas vary extensively in both their intrinsic resistance to antibiotics (ciprofloxacin and rifampicin) and persistence following exposure to these antibiotics. Crucially, we find that persistence correlates positively to antibiotic resistance across strains. However, we find that different genes control resistance and persistence implying that they are independent traits. Specifically, we find that the number of type II toxin-antitoxin systems (TAs) in the genome of a strain is correlated to persistence, but not resistance. Our study shows that persistence and antibiotic resistance are complementary, but independent, evolutionary adaptations to stress and it highlights the key role played by TAs in the evolution of persistence. PMID:26999656

  10. Beyond Antibiotics?

    Directory of Open Access Journals (Sweden)

    LE Nicolle

    2006-01-01

    Full Text Available The AMMI Canada meeting in March 2006 hosted a symposium exploring the potential alternatives to antibiotics for the prevention and treatment of infection. Four papers summarizing talks from that session are published in this issue of the Journal (1-4. These reviews address the scientific underpinnings for a number of proposed concepts, and summarize the current status of clinical use. The approaches - probiotics, bacteriophage therapy, and manipulation of innate immunity - are all intriguing but are still removed from immediate practical applications.

  11. Pseudomonas aeruginosa in Healthcare Settings

    Science.gov (United States)

    ... CDC.gov . Healthcare-associated Infections (HAIs) Share Compartir Pseudomonas aeruginosa in Healthcare Settings On this Page What ... and/or help treat infections? What is a Pseudomonas infection? Pseudomonas infection is caused by strains of ...

  12. Microbial assessment and prevalence of antibiotic resistance in polluted Oluwa River, Nigeria

    Directory of Open Access Journals (Sweden)

    T.A. Ayandiran

    2014-01-01

    Full Text Available Antibiotics are emerging environmental contaminants, causing both short-term and long-term alterations of natural microbial communities due to their high biological activities. The antibiotic resistance pattern of bacteria from anthropogenic polluted Oluwa River, Nigeria was carried out. Microbial profiling and antibiotic sensitivity tests were carried out on water and sediment samples using 13 different antibiotics. Microorganisms isolated include those in the genera Bacillus, Micrococcus, Pseudomonas, Streptococcus, Proteus and Staphylococcus. The microbial count of isolates from water samples ranged between 94.10 × 102 Cfu/100 ml and 156.20 × 102 Cfu/100 ml while that of sediment samples ranged from 2.55 × 104 Cfu g−1 to 14.30 × 104 Cfu g−1. From the water isolates, 100% resistance to antibiotics was found in Micrococcus spp. and Pseudomonas spp. while another Micrococcus, Streptococcus, Staphylococcus and Bacillus spp. showed between 40% and 90% resistances. From the sediment isolates, 100% resistance to antibiotics was found in a Bacillus spp. and Pseudomonas spp. while another Bacillus, Micrococcus, Staphylococcus, Streptococcus and Proteus spp. showed between 70% and 90% resistances. Multiple antibiotic resistance (MAR was shown by all the isolates and Bacillus, Micrococcus and Pseudomonas spp. showed the highest resistances (100% to all antibiotics. Thus, Oluwa River is not safe for public consumption.

  13. 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.

  14. Exposure to phages has little impact on the evolution of bacterial antibiotic resistance on drug concentration gradients

    OpenAIRE

    Zhang, Quan-Guo

    2014-01-01

    The use of phages for treating bacterial pathogens has recently been advocated as an alternative to antibiotic therapy. Here, we test a hypothesis that bacteria treated with phages may show more limited evolution of antibiotic resistance as the fitness costs of resistance to phages may add to those of antibiotic resistance, further reducing the growth performance of antibiotic-resistant bacteria. We did this by studying the evolution of phage-exposed and phage-free Pseudomonas fluorescens cul...

  15. Carbon Source Influences Population Heterogeneity In Pseudomonas Putida Kt2440 Biofilms

    DEFF Research Database (Denmark)

    Juel Christensen, Anne-Mette; Sternberg, Claus; Molin, Søren

    2015-01-01

    Introduction: Pseudomonas putida is well known as a potential cell factory for many different biochemicals. Biofilm-based production can be advantageous for possibly toxic products due to increased chemical tolerance and robustness. Biofilm cells frequently differentiate, which challenges the...

  16. ANTIBIOTIC RESISTANT BACTERIA FROM HALIOTIS TUBERCULATA AND MYTILUS GALLOPROVINCIALIS

    OpenAIRE

    F. Conte; Longo, S.; Malaspina, A.

    2009-01-01

    The antibiotic resistance (AR) of Gram negative bacteria from Haliotis tuberculata (Ht) and Mytilus galloprovincialis (Mg) was assessed. Essential differences between R profiles of Pseudomonas spp and of other strains was not observed. Strains AR from Ht and Mg was similar.

  17. 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. PMID:26608763

  18. Pseudomonas screening assay

    Science.gov (United States)

    Margalit, Ruth (Inventor)

    1993-01-01

    A method for the detection of Pseudomonas bacteria is described where an Azurin-specific antibody is employed for detecting the presence of Azurin in a test sample. The detection of the presence of Azurin in the sample is a conclusive indicator of the presence of the Pseudomonas bacteria since the Azurin protein is a specific marker for this bacterial strain.

  19. Recombineering Pseudomonas syringae

    Science.gov (United States)

    Here we report the identification of functions that promote genomic recombination of linear DNA introduced into Pseudomonas cells by electroporation. The genes encoding these functions were identified in Pseudomonas syringae pv. syringae B728a based on similarity to the lambda Red Exo/Beta and RecE...

  20. Accumulation of the Antibiotic Phenazine-1-Carboxylic Acid in the Rhizosphere of Dryland Cereals

    OpenAIRE

    Mavrodi, Dmitri V; Mavrodi, Olga V; Parejko, James A.; Bonsall, Robert F.; Kwak, Youn-Sig; Paulitz, Timothy C.; Thomashow, Linda S.; Weller, David M

    2012-01-01

    Natural antibiotics are thought to function in the defense, fitness, competitiveness, biocontrol activity, communication, and gene regulation of microorganisms. However, the scale and quantitative aspects of antibiotic production in natural settings are poorly understood. We addressed these fundamental questions by assessing the geographic distribution of indigenous phenazine-producing (Phz+) Pseudomonas spp. and the accumulation of the broad-spectrum antibiotic phenazine-1-carboxylic acid (P...

  1. Tolerating Zero Tolerance?

    Science.gov (United States)

    Moore, Brian N.

    2010-01-01

    The concept of zero tolerance dates back to the mid-1990s when New Jersey was creating laws to address nuisance crimes in communities. The main goal of these neighborhood crime policies was to have zero tolerance for petty crime such as graffiti or littering so as to keep more serious crimes from occurring. Next came the war on drugs. In federal…

  2. [Antibiotic resistance of bacteria to 6 antibiotics in secondary effluents of municipal wastewater treatment plants].

    Science.gov (United States)

    Lu, Sun-Qin; Li, Yi; Huang, Jing-Jing; Wei, Bin; Hu, Hong-Ying

    2011-11-01

    Prevalence of antibiotic-resistant bacteria in wastewater effluents is concerned as an emerging contaminant. To estimate antibiotic resistance in secondary effluents of municipal wastewater treatment plants, antibiotic tolerance of heterotrophic bacteria, proportion of antibiotic-resistant bacteria and hemi-inhibitory concentrations of six antibiotics (penicillin, ampicillin, cefalexin, chloramphenicol, tetracycline and rifampicin) were determined at two wastewater treatment plants (WWTPs) in Beijing. The results showed that proportions of ampicillin-resistant bacteria in WWTP-G and chloramphenicol-resistant bacteria in WWTP-Q were highest to 59% and 44%, respectively. The concentrations of ampicillin-resistant bacteria in the effluents of WWTP-G and WWTP-Q were as high as 4.0 x 10(3) CFU x mL(-1) and 3.5 x 10(4) CFU x mL(-1), respectively; the concentrations of chloramphenicol-resistant bacteria were 4.9 x 10(2) CFU x mL(-1) and 4.6 x 10(4) CFU x mL(-1), respectively. The data also indicated that the hemi-inhibitory concentrations of heterotrophic bacteria to 6 antibiotics were much higher than common concentrations of antibiotics in sewages, which suggested that antibiotic-resistant bacteria could exist over a long period in the effluents with low concentrations of antibiotics. Antibiotic-resistant bacteria could be a potential microbial risk during sewage effluent reuse or emission into environmental waters. PMID:22295644

  3. 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...

  4. Facts about Antibiotic Resistance

    Science.gov (United States)

    ... Recommendations Pediatric Treatment Recommendations Inpatient Healthcare Professionals Community Pharmacists Continuing Education & Curriculum Opportunities Weighing in on Antibiotic Resistance Improving Prescribing Outpatient Antibiotic Stewardship Interventions That Work Systematic Reviews ...

  5. Antibiotic / Antimicrobial Resistance Glossary

    Science.gov (United States)

    ... Recommendations Pediatric Treatment Recommendations Inpatient Healthcare Professionals Community Pharmacists Continuing Education & Curriculum Opportunities Weighing in on Antibiotic Resistance Improving Prescribing Outpatient Antibiotic Stewardship Interventions That Work Systematic Reviews ...

  6. 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.

  7. Biological production of monoethanolamine by engineered Pseudomonas putida S12

    NARCIS (Netherlands)

    Foti, M.J.; Médici, R.; Ruijssenaars, H.J.

    2013-01-01

    Pseudomonas putida S12 was engineered for the production of monoethanolamine (MEA) from glucose via the decarboxylation of the central metabolite l-serine, which is catalyzed by the enzyme l-serine decarboxylase (SDC).The host was first evaluated for its tolerance towards MEA as well as its endogeno

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

    OpenAIRE

    Das, Manash C.; Padmani Sandhu; Priya Gupta; Prasenjit Rudrapaul; Utpal C. De; Prosun Tribedi; Yusuf Akhter; Surajit Bhattacharjee

    2016-01-01

    Microbial biofilm are communities of surface-adhered cells enclosed in a matrix of extracellular polymeric substances. Extensive use of antibiotics to treat biofilm associated infections has led to the emergence of multiple drug resistant strains. Pseudomonas aeruginosa is recognised as a model biofilm forming pathogenic bacterium. Vitexin, a polyphenolic group of phytochemical with antimicrobial property, has been studied for its antibiofilm potential against Pseudomonas aeruginosa in combin...

  9. Antimicrobial Resistance and Molecular Typing of Pseudomonas Aeruginosa Isolated from Surgical Wounds in Lagos, Nigeria

    OpenAIRE

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

    2012-01-01

    The aim of the study was to determine the resistance patterns of Pseudomonas aeruginosa isolates recovered from patients with surgical wounds in hospitals and also to investigate their epidemiological relatedness using molecular typing techniques. Twenty Pseudomonas sp. isolated from surgical wounds were subjected to antibiotic susceptibility testing by disk diffusion, plasmid profile, SDS-PAGE and PCR using the parC, gyr A gene and RAPD using the 1254 primer. The isolates showed resistance t...

  10. Antimicrobial Susceptibility Pattern of Pseudomonas aeruginosa Isolated from Patients Referring to Hospitals

    OpenAIRE

    Zeynab Golshani; Ali Mohammad Ahadi; Ali Sharifzadeh

    2012-01-01

    Please cite this article as: Golshani Z, Ahadi AM, Sharifzadeh A. Antimicrobial Susceptibility Pattern of Pseudomonas aeruginosa Isolated from Patients Referring to Hospitals. Arch Hyg Sci 2012;1(2):48-53. Abstract: Background & Aims of the Study: The aim of this study was to detect and survey the antibiotic resistance pattern of Pseudomonas (P.) aeruginosa isolated from patients in Isfahan (located in central Iran) hospitals. Materials & Methods : A Total of 50 clinical isola...

  11. 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....

  12. Tailored Antibiotic Combination Powders for Inhaled Rotational Antibiotic Therapy.

    Science.gov (United States)

    Lee, Sie Huey; Teo, Jeanette; Heng, Desmond; Ng, Wai Kiong; Zhao, Yanli; Tan, Reginald B H

    2016-04-01

    Respiratory lung infections due to multidrug-resistant (MDR) superbugs are on a global upsurge and have very grim clinical outcomes. Their MDR profile makes therapeutic options extremely limited. Although a highly toxic antibiotic, colistin, is favored today as a "last-line" therapeutic against these hard-to-treat MDR pathogens, it is fast losing its effectiveness. This work therefore seeks to identify and tailor-make useful combination regimens (that are potentially rotatable and synergistic) as attractive alternative strategies to address the rising rates of drug resistance. Three potentially rotatable ternary dry powder inhaler constructs (each involving colistin and 2 other different-classed antibiotics chosen from rifampicin, meropenem, and tigecycline) were identified (with distinct complementary killing mechanisms), coformulated via spray drying, evaluated on their aerosol performance using a Next-Generation Impactor and tested for their efficacies against a number of MDR pathogens. The powder particles were of respirable size (d50, 3.1 ± 0.3 μm-3.4 ± 0.1 μm) and predominantly crumpled in morphology. When dispersed via a model dry powder inhaler (Aerolizer(®)) at 60 L/min, the powders showed concomitant in vitro deposition with fine particle fractions of ∼53%-70%. All formulations were successfully tested in the laboratory to be highly effective against the MDR pathogens. In addition, a favorable synergistic interaction was detected across all 3 formulations when tested against MDR Pseudomonas aeruginosa. PMID:27019964

  13. Indicator For Pseudomonas Bacteria

    Science.gov (United States)

    Margalit, Ruth

    1990-01-01

    Characteristic protein extracted and detected. Natural protein marker found in Pseudomonas bacteria. Azurin, protein containing copper readily extracted, purified, and used to prepare antibodies. Possible to develop simple, fast, and accurate test for marker carried out in doctor's office.

  14. BIOSYNTHESIS AND PROPERTIES OF ANTIBIOTIC BATUMIN

    Directory of Open Access Journals (Sweden)

    V. V. Klochko

    2014-12-01

    Full Text Available Biosynthesis of antistaphylococcal antibiotic batumin under periodic conditions of Pseudomonas batumici growth has been studied. Antibiotic synthesis in fermenter occurred across the culture growth and achieved its maximal value after 50–55 hours. The active oxygen utilization by the producing strain was observed during 20–55 hours of fermentation with maximum after 40–45 hours. Antibiotic yield was 175–180 mg/l and depended on intensity of aeration. contrast to «freshly isolated» antibiotic after fermentation the long-term kept batumin has shown two identical by molecular mass peaks according to the chromato-mass spectrometric analysis. Taking into account of batumin molecule structure the conclusion has been made that the most probable isomerization type is keto-enolic tautomerism. At the same time batumin is diastereoisomer of kalimantacin A which has the same chemical structure. The optic rotation angle is [α]d25 = +56.3° for kalimantacin and [α]d25 = –13.5° for batumin. The simultaneous P. batumici growth and antibiotic biosynthesis and the ability of this molecule to optical isomerisation and keto-enolic forms formation allow us to suppose that batumin plays a certain role in metabolism of the producing strain.

  15. 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...

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

    Science.gov (United States)

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

    2014-12-01

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

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

    International Nuclear Information System (INIS)

    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)

  18. Characterization of the Polymyxin B Resistome of Pseudomonas aeruginosa

    OpenAIRE

    Fernandez, L.; Alvarez-Ortega, C.; Wiegand, I.; Olivares, J.; Kocincova, D.; Lam, J S; Martinez, J.L.; Hancock, R. E. W.

    2013-01-01

    Multidrug resistance in Pseudomonas aeruginosa is increasingly becoming a threat for human health. Indeed, some strains are resistant to almost all currently available antibiotics, leaving very limited choices for antimicrobial therapy. In many such cases, polymyxins are the only available option, although as their utilization increases so does the isolation of resistant strains. In this study, we screened a comprehensive PA14 mutant library to identify genes involved in changes of susceptibi...

  19. STUDY OF METALLO-Β-LACTAMASE PRODUCTION IN CLINICAL ISOLATES OF PSEUDOMONAS AERUGINOSA IN A TEACHING HOSPITAL OF RURAL GUJARAT - INDIA

    OpenAIRE

    Yagnesh; Agravat

    2013-01-01

    ABSTRACT: BACKGROUND: Pseudomonas aeruginosa exhibits intrinsic resistanc e to a variety of antimicrobials including beta lactams. Imipenem-res istant Pseudomonas aeruginosa resulting from metallo-β-lactamases production represent a signifi cant and rapidly emerging problem and threat in most part of the world. Detection of metallo-β-l actamase (MBL)-producing Pseudomonas aeruginosa is crucial for the optimal antibiotic tr eatment of the seriously ill patients. ...

  20. Digestion of algin by Pseudomonas maltophilia and Pseudomonas putida.

    OpenAIRE

    von Riesen, V L

    1980-01-01

    Pseudomonas maltophilia and Pseudomonas putida were identified as alginolytic species. Two media used for demonstrating alginolytic activity are described. The applied aspects of the ability of these two species to digest algin are discussed.

  1. 40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. 180.1107 Section 180.1107 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES...

  2. Induced systemic resistance (ISR) in Arabidopsis thaliana against Pseudomonas syringae pv. tomato by 2,4-diacetylphloroglucinol-producing Pseudomonas fluorescens

    Science.gov (United States)

    Pseudomonas fluorescens strains that produce the polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are among the most effective rhizobacteria that suppress root and crown rots, wilts and damping-off diseases of a variety of crops, and they play a key role in the natural suppressiveness of ...

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

    Directory of Open Access Journals (Sweden)

    Marcel Hoppentocht

    Full Text Available 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.To assess local tolerability and the pharmacokinetic parameters of inhaled excipient free dry powder tobramycin as free base administered with the Cyclops dry powder inhaler to participants with non-cystic fibrosis bronchiectasis. The free base and absence of excipients reduces the inhaled powder dose.Eight participants in the study were trained in handling the device and inhaling correctly. During drug administration the inspiratory flow curve was recorded. Local tolerability was assessed by spirometry and recording adverse events. Serum samples were collected before, and 15, 30, 45, 60, 75, 90, 105, 120 min; 4, 8 and 12 h after inhalation.Dry powder tobramycin base was well tolerated and mild tobramycin-related cough was reported only once. A good drug dose-serum concentration correlation was obtained. Relatively small inhaled volumes were computed from the recorded flow curves, resulting in presumably substantial deposition in the central airways-i.e., at the site of infection.In this first study of inhaled dry powder tobramycin free base in non-cystic fibrosis bronchiectasis patients, the free base of tobramycin and the administration with the Cyclops dry powder device were well tolerated. Our data support further clinical studies to evaluate safety and efficacy of this compound in this population.

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

    Science.gov (United States)

    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. Objectives To assess local tolerability and the pharmacokinetic parameters of inhaled excipient free dry powder tobramycin as free base administered with the Cyclops dry powder inhaler to participants with non-cystic fibrosis bronchiectasis. The free base and absence of excipients reduces the inhaled powder dose. Methods Eight participants in the study were trained in handling the device and inhaling correctly. During drug administration the inspiratory flow curve was recorded. Local tolerability was assessed by spirometry and recording adverse events. Serum samples were collected before, and 15, 30, 45, 60, 75, 90, 105, 120 min; 4, 8 and 12 h after inhalation. Results and Discussion Dry powder tobramycin base was well tolerated and mild tobramycin-related cough was reported only once. A good drug dose-serum concentration correlation was obtained. Relatively small inhaled volumes were computed from the recorded flow curves, resulting in presumably substantial deposition in the central airways—i.e., at the site of infection. Conclusions In this first study of inhaled dry powder tobramycin free base in non-cystic fibrosis bronchiectasis patients, the free base of tobramycin and the administration with the Cyclops dry powder device were well tolerated. Our data support further clinical studies to evaluate safety and efficacy of this compound in this population. PMID:26959239

  5. Comparison of the complete genome sequences of Pseudomonas syringae pv. syringae B728a and pv. tomato DC3000

    Energy Technology Data Exchange (ETDEWEB)

    Feil, Helene [University of California, Berkeley; Feil, William [University of California, Berkeley; Chain, Patrick S. G. [Lawrence Livermore National Laboratory (LLNL); Larimer, Frank W [ORNL; DiBartolo, Genevieve [U.S. Department of Energy, Joint Genome Institute; Copeland, A [U.S. Department of Energy, Joint Genome Institute; Lykidis, A [U.S. Department of Energy, Joint Genome Institute; Trong, Stephen [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Goltsman, Eugene [U.S. Department of Energy, Joint Genome Institute; Thiel, James [U.S. Department of Energy, Joint Genome Institute; Malfatti, Stephanie [Lawrence Livermore National Laboratory (LLNL); Loper, Joyce E. [U.S. Department of Agriculture, Agricultural Research Service; Detter, J C [U.S. Department of Energy, Joint Genome Institute; Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Richardson, P M [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Lindow, Steven E. [University of California, Berkeley

    2005-01-01

    The complete genomic sequence of Pseudomonas syringae pv. syringae B728a (Pss B728a) has been determined and is compared with that of A syringae pv. tomato DC3000 (Pst DC3000). The two pathovars of this economically important species of plant pathogenic bacteria differ in host range and other interactions with plants, with Pss having a more pronounced epiphytic stage of growth and higher abiotic stress tolerance and Pst DC3000 having a more pronounced apoplastic growth habitat. The Pss B728a genome (6.1 Mb) contains a circular chromosome and no plasmid, whereas the Pst DC3000 genome is 6.5 mbp in size, composed of a circular chromosome and two plasmids. Although a high degree of similarity exists between the two sequenced Pseudomonads, 976 protein-encoding genes are unique to Pss B728a when compared with Pst DC3000, including large genomic islands likely to contribute to virulence and host specificity. Over 375 repetitive extragenic palindromic sequences unique to Pss B728a when compared with Pst DC3000 are widely distributed throughout the chromosome except in 14 genomic islands, which generally had lower GC content than the genome as a whole. Content of the genomic islands varies, with one containing a prophage and another the plasmid pKLC102 of Pseudomonas aeruginosa PAO1. Among the 976 genes of Pss B728a with no counterpart in Pst DC3000 are those encoding for syringopeptin, syringomycin, indole acetic acid biosynthesis, arginine degradation, and production of ice nuclei. The genomic comparison suggests that several unique genes for Pss B728a such as ectoine synthase, DNA repair, and antibiotic production may contribute to the epiphytic fitness and stress tolerance of this organism.

  6. Comparison of the complete genome sequences of Pseudomonas syringae pv. syringae B728a and pv. tomato DC3000

    Energy Technology Data Exchange (ETDEWEB)

    Feil, H; Feil, W S; Chain, P; Larimer, F; DiBartolo, G; Copeland, A; Lykidis, A; Trong, S; Nolan, M; Goltsman, E; Thiel, J; Malfatti, S; Loper, J E; Lapidus, A; Detter, J C; Land, M; Richardson, P M; Kyrpides, N C; Ivanova, N; Lindow, S E

    2005-07-14

    The complete genomic sequence of Pseudomonas syringae pathovar syringae B728a (Pss B728a), has been determined and is compared with that of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). The two pathovars of this economically important species of plant pathogenic bacteria differ in host range and other interactions with plants, with Pss having a more pronounced epiphytic stage of growth and higher abiotic stress tolerance and Pst DC3000 having a more pronounced apoplastic growth habitat. The Pss B728a genome (6.1 megabases) contains a circular chromosome and no plasmid, whereas the Pst DC3000 genome is 6.5 mbp in size, composed of a circular chromosome and two plasmids. While a high degree of similarity exists between the two sequenced Pseudomonads, 976 protein-encoding genes are unique to Pss B728a when compared to Pst DC3000, including large genomic islands likely to contribute to virulence and host specificity. Over 375 repetitive extragenic palindromic sequences (REPs) unique to Pss B728a when compared to Pst DC3000 are widely distributed throughout the chromosome except in 14 genomic islands, which generally had lower GC content than the genome as a whole. Content of the genomic islands vary, with one containing a prophage and another the plasmid pKLC102 of P. aeruginosa PAO1. Among the 976 genes of Pss B728a with no counterpart in Pst DC3000 are those encoding for syringopeptin (SP), syringomycin (SR), indole acetic acid biosynthesis, arginine degradation, and production of ice nuclei. The genomic comparison suggests that several unique genes for Pss B728a such as ectoine synthase, DNA repair, and antibiotic production may contribute to epiphytic fitness and stress tolerance of this organism.

  7. Hot Tub Rash (Pseudomonas Folliculitis)

    Science.gov (United States)

    ... clinical tools newsletter | contact Share | Hot Tub Rash ( Pseudomonas Folliculitis) Information for adults A A A This ... small pus-filled lesions. Overview Hot tub rash ( Pseudomonas folliculitis) is an infection of the hair follicle ...

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

    Science.gov (United States)

    Vital-Lopez, Francisco G; Reifman, Jaques; Wallqvist, Anders

    2015-10-01

    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 cells. Developing treatments against biofilms requires an understanding of bacterial biofilm-specific physiological traits. Research efforts have started to elucidate the intricate mechanisms underlying biofilm development. However, many aspects of these mechanisms are still poorly understood. Here, we addressed questions regarding biofilm metabolism using a genome-scale kinetic model of the P. aeruginosa metabolic network and gene expression profiles. Specifically, we computed metabolite concentration differences between known mutants with altered biofilm formation and the wild-type strain to predict drug targets against P. aeruginosa biofilms. We also simulated the altered metabolism driven by gene expression changes between biofilm and stationary growth-phase planktonic cultures. Our analysis suggests that the synthesis of important biofilm-related molecules, such as the quorum-sensing molecule Pseudomonas quinolone signal and the exopolysaccharide Psl, is regulated not only through the expression of genes in their own synthesis pathway, but also through the biofilm-specific expression of genes in pathways competing for precursors to these molecules. Finally, we investigated why mutants defective in anthranilate degradation have an impaired ability to form biofilms. Alternative to a previous hypothesis that this biofilm reduction is caused by a decrease in energy production, we proposed that the dysregulation of the synthesis of secondary metabolites derived from anthranilate and chorismate is what impaired the biofilms of these mutants. Notably, these insights generated through our kinetic model-based approach are not accessible from previous constraint-based model analyses of P. aeruginosa biofilm

  9. Strengthening Control of Antibiotics

    Institute of Scientific and Technical Information of China (English)

    EthelLu

    2005-01-01

    IT is a well-known fact that buy-ng guns is much easier than purchasing antibiotics in the United States. In China, however, the situation is different. According to a recent WHO survey,about 80 percent of Chinese inpatients take antibiotic medicines, and 58 percent of them are prescribed multifunctional antibiotics,

  10. 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.

  11. Antibiotic resistant in microorganisms

    Science.gov (United States)

    Antimicrobial agents are necessary for use in veterinary medicine including the production of food producing animals. Antibiotic use is indicated for the treatment of bacterial target organisms and/or disease for which the antibiotic was developed. However, an unintended consequence of antibiotic ...

  12. New antibiotic agents for bloodstream infections.

    Science.gov (United States)

    Vergidis, Paschalis I; Falagas, Matthew E

    2008-11-01

    Infections due to multidrug-resistant pathogens have shown a dramatic worldwide increase in prevalence. Bloodstream infections (BSIs) represent an important cause of morbidity and mortality in hospitalised patients. Research in the field led to the introduction of several novel antibiotic agents in the fight against bacterial pathogens. New antibiotics used against Gram-positive bacteria, mainly meticillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci, include daptomycin, linezolid, quinupristin/dalfopristin and semisynthetic lipoglycopeptides. Among the Gram-negative bacteria, extended-spectrum beta-lactamase-producing Enterobacteriaceae as well as highly resistant Pseudomonas and Acinetobacter isolates are of particular concern. Doripenem is a recently approved carbapenem. Polymyxins are reconsidered as valuable therapeutic options for Gram-negative infections. Tigecycline, a glycylcycline, and ceftobiprole, a novel cephalosporin under investigation, have activity both against Gram-positive and Gram-negative organisms. In addition to the above agents, alternative treatment approaches that require further investigation have also been introduced into clinical practice. These include antibiotic lock therapy and continuous intravenous administration of antibiotics. In this article, we review the above treatment options for BSIs based on current clinical evidence. Comparative trials specifically focusing on patients with bacteraemia were generally not performed; however, a proportion of patients from the reported studies did have bacteraemia. PMID:18723329

  13. 糖尿病足分离的铜绿假单胞菌对氨基糖苷类抗生素耐药机制探讨%Study on aminoglycoside antibiotics resistance of Pseudomonas aeruginosa isolated from diabetic foot infections

    Institute of Scientific and Technical Information of China (English)

    乌洪芳; 孙茜; 李玉珠; 张敏; 孟玲玲; 李代清

    2015-01-01

    Objective To investigate the clinical features, phenotypes and genotypes of Pseudomonas aeruginosa (PA) strains isolated from patients with diabetic foot infection (DFI) resisting to aminoglycosides antibiotics (AmAn). Methods The clinical profiles of 209 DFI patients hospitalized in the Tianjin Metabolic Diseases Hospital were collected and ana⁃lyzed. Forty-one PA strains were identified, and their antibiotic resistance profiles were obtained. The DNAs of PA isolates were extracted and applied to amplifications for several aminoglycosides modifying enzyme genes, including aac(3′)-Ⅰ, aac (3′)-Ⅱ, aac(6′)-Ⅰb, aac(6′)-Ⅱ, ant(2′′)-Ⅰand ant(3′′)-Ⅰby PCR method. Combining with the clinical features and the antibiotic resistance profiles, the relationship between genotypes and phenotypes of the PA strains was analyzed. Results Gram positive bacteria (G+) were the majority of the pathogen with 51.67%detection rate. The total detection rate of PA was 19.62%, listed as the top one pathogenic bacterium among gram negative bacteria (47.67%). There was significant difference in the ratio of ulcer area≥4 cm2 between PA group and non-PA group and G+group. There were significantly higher inci⁃dence rate of ischemic ulcer and osteomyelitis in PA group than those of G+group. There were higher clinical characteristics and ulcer depth (SAD) score, and increased hypersensitive C-reactive protein in PA group than those of G+ group. There were 30 strains of PA being resistant to AmAn (73.17%). The predominant drug resistance gene to AmAn was ant(3′′)-Ⅰ(65.85%), and aac(3′)-Ⅰgene was not found from all PA isolates. Conclusion The detection rate of PA isolated from DFI patients was higher, and patients were with the characteristics of larger, deeper and severe ischemia of ulcer area. The phe⁃nomenon of PA resistant to AmAn was more serious, and ant(3′′)-Ⅰgene identified from PA isolates was the most common resistance gene identified to Am

  14. Stenosis triggers spread of helical Pseudomonas biofilms in cylindrical flow systems

    Science.gov (United States)

    Espeso, David R.; Carpio, Ana; Martínez-García, Esteban; de Lorenzo, Victor

    2016-06-01

    Biofilms are multicellular bacterial structures that adhere to surfaces and often endow the bacterial population with tolerance to antibiotics and other environmental insults. Biofilms frequently colonize the tubing of medical devices through mechanisms that are poorly understood. Here we studied the helicoidal spread of Pseudomonas putida biofilms through cylindrical conduits of varied diameters in slow laminar flow regimes. Numerical simulations of such flows reveal vortical motion at stenoses and junctions, which enhances bacterial adhesion and fosters formation of filamentous structures. Formation of long, downstream-flowing bacterial threads that stem from narrowings and connections was detected experimentally, as predicted by our model. Accumulation of bacterial biomass makes the resulting filaments undergo a helical instability. These incipient helices then coarsened until constrained by the tubing walls, and spread along the whole tube length without obstructing the flow. A three-dimensional discrete filament model supports this coarsening mechanism and yields simulations of helix dynamics in accordance with our experimental observations. These findings describe an unanticipated mechanism for bacterial spreading in tubing networks which might be involved in some hospital-acquired infections and bacterial contamination of catheters.

  15. Stenosis triggers spread of helical Pseudomonas biofilms in cylindrical flow systems.

    Science.gov (United States)

    Espeso, David R; Carpio, Ana; Martínez-García, Esteban; de Lorenzo, Victor

    2016-01-01

    Biofilms are multicellular bacterial structures that adhere to surfaces and often endow the bacterial population with tolerance to antibiotics and other environmental insults. Biofilms frequently colonize the tubing of medical devices through mechanisms that are poorly understood. Here we studied the helicoidal spread of Pseudomonas putida biofilms through cylindrical conduits of varied diameters in slow laminar flow regimes. Numerical simulations of such flows reveal vortical motion at stenoses and junctions, which enhances bacterial adhesion and fosters formation of filamentous structures. Formation of long, downstream-flowing bacterial threads that stem from narrowings and connections was detected experimentally, as predicted by our model. Accumulation of bacterial biomass makes the resulting filaments undergo a helical instability. These incipient helices then coarsened until constrained by the tubing walls, and spread along the whole tube length without obstructing the flow. A three-dimensional discrete filament model supports this coarsening mechanism and yields simulations of helix dynamics in accordance with our experimental observations. These findings describe an unanticipated mechanism for bacterial spreading in tubing networks which might be involved in some hospital-acquired infections and bacterial contamination of catheters. PMID:27272623

  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. PMID:26286796

  17. The dlt genes play a role in antimicrobial tolerance of Streptococcus mutans biofilms

    DEFF Research Database (Denmark)

    Nilsson, Martin; Rybtke, Morten; Givskov, Michael;

    2016-01-01

    Microbial biofilms are tolerant to antibiotic treatment and therefore cause problematic infections. Knowledge about the molecular mechanisms underlying biofilm-associated antimicrobial tolerance will aid the development of antibiofilm drugs. Screening of a Streptococcus mutans transposon mutant...

  18. Pseudomonas aeruginosa biofilm infections

    DEFF Research Database (Denmark)

    Tolker-Nielsen, Tim

    2014-01-01

    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...

  19. Incidence of cephalosporin resistance among clinical isolates of Pseudomonas aeruginosa in Ibadan, South- Western Nigeria

    Directory of Open Access Journals (Sweden)

    Oladipo E.K

    2015-12-01

    Full Text Available Background: The emergence of beta-lactam resistance in Pseudomonas aeruginosa is a major global challenge, particularly, the rise in the resistance to 3rd and 4th generation cephalosporins. Aim: This study was carried out to determine the resistance pattern of Pseudomonas aeruginosa to different generations of cephalosporins. Methods: A total number of one hundred clinical isolates of Pseudomonas aeruginosa were collected from June to November 2014 at University Teaching Hospital Ibadan, Oyo State. These were tested for their sensitivity to antibiotics by means of disc diffusion method using prepared antibiotics disc containing different μ of antibiotics; Cefotaxine (30μ, Cefaclor (30μ, Cefamandole (30μ, Cefixime (5μ, Cefepime (30μ, Cefpodoxime (30μ and Ceftazidime (30μ. Results: Pseudomonas aeruginosa showed absolute resistance to all antibiotics used except Ceftazidime, and Cefepime which are third and fourth generation of cephalosporin respectively. Ceftazidime had minimal resistant of 21% and higher susceptibility rate of 76%, Cefepime had the highest susceptibility rate of 90% and minimal resistance of 6%. Cefotaxime and Cefpodoxime had minimal intermediate of 1%, Ceftazidime of 3% and Cefepime of 4%. Conclusion: The result from this study provided more evidence that among third generation of cephalosporins used, some are more active than the other while fourth generation is still the most effective of all other generations. Knowledge on the distribution of cephalosporin-resistant organisms is of ultimate importance as a guide in empirical therapy, taking note of preventive strategies as well as control measures against the spread of resistant microorganisms.

  20. Adaptation of Pseudomonas aeruginosa to the cystic fibrosis airway: an evolutionary perspective

    DEFF Research Database (Denmark)

    Folkesson, Anders; Jelsbak, Lars; Yang, Lei;

    2012-01-01

    The airways of patients with cystic fibrosis (CF) are nearly always infected with many different microorganisms. This environment offers warm, humid and nutrient-rich conditions, but is also stressful owing to frequent antibiotic therapy and the host immune response. Pseudomonas aeruginosa is com...

  1. Glutathione exhibits antibacterial activity and increases tetracycline efficacy against Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    ZHANG YaNi; DUAN KangMin

    2009-01-01

    Glutathione (GSH) plays important roles in pulmonary diseases, and inhaled GSH therapy has been used to treat cystic fibrosis (CF) patients in clinical trials. The results in this report revealed that GSH altered the sensitivity of Pseudomonas aeruginosa to different antibiotics through pathways unrelated to the oxidative stress as generally perceived. In addition, GSH and its oxidized form inhibited the growth of P. Aeruginosa.

  2. 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...

  3. Pseudomonas aeruginosa biofilm infections in cystic fibrosis: insights into pathogenic processes and treatment strategies

    DEFF Research Database (Denmark)

    Hassett, Daniel J; Korfhagen, Thomas R; Irvin, Randall T;

    2010-01-01

    CF airway mucus can be infected by opportunistic microorganisms, notably Pseudomonas aeruginosa. Once organisms are established as biofilms, even the most potent antibiotics have little effect on their viability, especially during late-stage chronic infections. Better understanding of the mechani...... mechanisms used by P. aeruginosa to circumvent host defenses and therapeutic intervention strategies is critical for advancing novel treatment strategies....

  4. Pseudomonas aeruginosa biofilms in the respiratory tract of cystic fibrosis patients

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Jensen, Peter Østrup; Fiandaca, Mark J; Pedersen, Jette; Hansen, Christine Rønne; Andersen, Claus Bøgelund; Pressler, Tacjana; Givskov, Michael; Høiby, Niels

    2009-01-01

    The present study was undertaken to investigate the appearance and location of Pseudomonas aeruginosa in the cystic fibrosis (CF) lung and in sputum. Samples include preserved tissues of CF patients who died due to chronic P. aeruginosa lung infection prior to the advent of intensive antibiotic...

  5. Epistatic Mutations And Unpredictable Phenotypes In Pseudomonas Aeruginosa

    DEFF Research Database (Denmark)

    Andresen, Eva Kammer; Abou Hachem, Maher; Jelsbak, Lars

    2015-01-01

    Pseudomonas aeruginosa is an opportunistic pathogen, able to adapt to stressful environments such as the cystic fibrosis (CF) airways. Adaptation of P. aeruginosa to the CF environment is associated with phenotypic changes, such as switch in mucoidy, antibiotic resistance and loss of virulence...

  6. 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...

  7. RHIZOSPHERE COLONIZATION OF TRANSGENIC AND WILD-TYPE PSEUDOMONAS FLUORESCENS IS MODULATED BY THE CROP SPECIES

    Science.gov (United States)

    Pseudomonas fluorescens strain Q8r1-96 (genotype D) produces 2,4-diacetylphloroglucinol (DAPG). Transgenic strain Z30-97, constructed by stably inserting the phenazine-1-carboxylic acid (PCA) biosynthetic locus from P. fluorescens 2-79 into Q8r1-96, produces both antibiotics in vitro and in situ. Th...

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

    Directory of Open Access Journals (Sweden)

    ALMEIDA João Fernando Lourenço de

    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.

  9. Contributions of efflux pumps to high level resistance of Pseudomonas aeruginosa to ciprofloxacin

    Institute of Scientific and Technical Information of China (English)

    WANG Dan-dan; SUN Tie-ying; HU Yun-jian

    2007-01-01

    @@ Pseudomonas aeruginosa (P. aeruginosa) is one of the leading pathogens involved in nosocomial pneumonia. In addition, P. aeruginosa infection is associated with significant morbidity and mortality.1 A major problem in P. aeruginosa infection is that this organism exhibits natural and acquired resistance to many structurally and functionally diverse antibiotics.

  10. 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

  11. USMB-induced synergistic enhancement of aminoglycoside antibiotics in biofilms.

    Science.gov (United States)

    Ronan, Evan; Edjiu, Narbeh; Kroukamp, Otini; Wolfaardt, Gideon; Karshafian, Raffi

    2016-07-01

    This study evaluated the effect of combining antibiotics with ultrasound and microbubbles (USMB) toward the eradication of biofilms. Pseudomonas aeruginosa PAO1 biofilms were treated with the antibiotics gentamicin sulfate or streptomycin sulfate, or a combination of USMB with the respective antibiotics. Biofilm structure was quantified using confocal laser scanning microscopy with COMSTAT analysis, while activity was measured as whole-biofilm CO2 production in a continuous-flow biofilm model. The combined antibiotic-USMB treatment significantly impacted biofilm biomass, thickness and surface roughness compared to antibiotics alone (p<0.05). USMB exposure caused the formation of craters (5-20μm in diameter) in the biofilms, and when combined with gentamicin, activity was significantly lower, compared to gentamicin, USMB or untreated controls, respectively. Interestingly, the CO2 production rate following combined streptomycin-USMB treatment was higher than after streptomycin alone, but significantly lower than USMB alone and untreated control. These results show strong evidence of a synergistic effect between antibiotics and USMB, although the varied response to different antibiotics emphasize the need to optimize the USMB exposure conditions to maximize this synergism and ultimately transfer this technology into clinical or industrial practice. PMID:27111871

  12. 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...

  13. Effect of Caffeic Acid and Low-Power Laser Light Co-Exposure on Viability of Pseudomonas aeruginosa

    OpenAIRE

    Gheibi; Divan Khosroshahi; Habibi

    2015-01-01

    Background The resistance of Pseudomonas aeruginosa to antibiotics is a big problem, especially in burns and wound infections. Laser irradiation affects microorganisms by denaturing their proteins, which involves changes in the chemical or physical properties of the protein. Objectives The aim of this study was to investigate the effect of caffeic acid and low-power laser light co-exposure on Pseudomonas aeruginosa isolated from b...

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

    OpenAIRE

    Yongming Sang; Frank Blecha

    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 ...

  15. Frontline antibiotic therapy.

    Science.gov (United States)

    MacGowan, Alasdair; Albur, Maha

    2013-06-01

    The need to use front-line antibiotics wisely has never been greater. Antibiotic resistance and multi-drug resistant infection, driven by antibiotic use, remain major public health and professional concerns. To overcome these infection problems, use of older antibiotics active against multi drug-resistant pathogens is increasing - for example, colistin, fosfomycin, pivmecillinam, pristinamycin, temocillin and oral tetracyclines. The number of new antibacterials reaching clinical practice has reduced significantly in the last 20 years, most being focused on therapy of Gram-positive infection - eg linezolid, daptomycin, telavancin and ceftaroline. Recent guidance on antibiotic stewardship in NHS trusts in England is likely to provide a backdrop to antibiotic use in hospitals in the next 5 years. PMID:23760700

  16. High Antibiotic Consumption

    DEFF Research Database (Denmark)

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

    2014-01-01

    a high proportion of antibiotics not recommended as first choice in primary health care. In conclusion, heavy antibiotic users consisted mainly of children and old adults. Inappropriate overuse of antibiotics (high quantity, high frequency, and inappropriate antibiotic choice) leads to a substantial...... individuals with highest consumption) were responsible for 21% of the total DDD consumed and received ≥6 packages per year. Elderly adults (≥60 years) and small children (0-9 years) were those exposed to the highest volume of antibiotics and with the most frequent exposure, respectively. Heavy users received...... risk of the emergence and spread of resistant bacteria, and interventions to reduce overuse of antibiotics should therefore primarily be targeted children and elderly people....

  17. Physiology of Pseudomonas aeruginosa in biofilms as revealed by transcriptome analysis

    Directory of Open Access Journals (Sweden)

    Parker Albert

    2010-11-01

    Full Text Available Abstract Background Transcriptome analysis was applied to characterize the physiological activities of Pseudomonas aeruginosa grown for three days in drip-flow biofilm reactors. Conventional applications of transcriptional profiling often compare two paired data sets that differ in a single experimentally controlled variable. In contrast this study obtained the transcriptome of a single biofilm state, ranked transcript signals to make the priorities of the population manifest, and compared ranki ngs for a priori identified physiological marker genes between the biofilm and published data sets. Results Biofilms tolerated exposure to antibiotics, harbored steep oxygen concentration gradients, and exhibited stratified and heterogeneous spatial patterns of protein synthetic activity. Transcriptional profiling was performed and the signal intensity of each transcript was ranked to gain insight into the physiological state of the biofilm population. Similar rankings were obtained from data sets published in the GEO database http://www.ncbi.nlm.nih.gov/geo. By comparing the rank of genes selected as markers for particular physiological activities between the biofilm and comparator data sets, it was possible to infer qualitative features of the physiological state of the biofilm bacteria. These biofilms appeared, from their transcriptome, to be glucose nourished, iron replete, oxygen limited, and growing slowly or exhibiting stationary phase character. Genes associated with elaboration of type IV pili were strongly expressed in the biofilm. The biofilm population did not indicate oxidative stress, homoserine lactone mediated quorum sensing, or activation of efflux pumps. Using correlations with transcript ranks, the average specific growth rate of biofilm cells was estimated to be 0.08 h-1. Conclusions Collectively these data underscore the oxygen-limited, slow-growing nature of the biofilm population and are consistent with antimicrobial tolerance due

  18. Intensive Care Unit Infections and Antibiotic Use

    Directory of Open Access Journals (Sweden)

    Ayşegül Yeşilkaya

    2011-07-01

    Full Text Available Burn wound infections is the leading cause of morbidity and mortality in burn trauma patients. Although burn wound is sterile at the beginning, because of risk factors such as prolonged hospital stay, immunesuppression and burn affecting large body surface area, colonisation firstly with Staphylococcus aureus and then Pseudomonas aeruginosa will occur later. Delay in wound closure and treatment with broad-spectrum antibiotic will result wound colonisation with antibiotic-resistant bacteria. To control colonization and to prevent burn wound infection topical antimicrobial dressings are used. The criteria used for the diagnosis of sepsis and wound infections are different in burn victims. Surface swabs from burn wounds must be cultured for the early assestment of infection. Although histopathological examination and quantitative culture of wound tissue biopsy has been known as the gold standard for the verification of invasive burn wound infection, many burn centers cannot do histopathological examination. When the traditional treatment modalities such as debridement of necrotic tissue, cleaning of wound and topical antimicrobial dressing application fails in the management of burn patient, cultures must be taken from possible foci of infection for the early diagnosis. After specimen collection, empirical bactericidal systemic antibiotic treatment should be started promptly. Inappropriate utilization of antibiotics may cause selection of resistant bacteria in the flora of the patient and of the burn unit which facilitates an infection or an outbreak at the end. Infection control in the burn unit includes surveillance cultures, cohort patient care staff, standard isolation precautions, strict hand hygiene compliance and appropariate antibiotic utilization. (Journal of the Turkish Society Intensive Care 2011; 9 Suppl: 55-61

  19. Understanding Antibiotic Resistance

    OpenAIRE

    Goulart-Touma, Christiane

    2014-01-01

    The evolution of antibiotic resistance among bacteria threatens our continued ability to treat infectious diseases. The need for sustainable strategies to cure bacterial infections has never been greater. So far, all attempts to restore susceptibility after resistance arises have been unsuccessful, including restrictions on prescribing antibiotics (Andersson DI et al.2011) and antibiotic cycling (Andersson DI et al. 2005, Bergstrom CT et al. 2004). Part of the problem may be that those effor...

  20. Endopeptidase-Mediated Beta Lactam Tolerance

    OpenAIRE

    Dörr, Tobias; Davis, Brigid M.; Waldor, Matthew K.

    2015-01-01

    In many bacteria, inhibition of cell wall synthesis leads to cell death and lysis. The pathways and enzymes that mediate cell lysis after exposure to cell wall-acting antibiotics (e.g. beta lactams) are incompletely understood, but the activities of enzymes that degrade the cell wall (‘autolysins’) are thought to be critical. Here, we report that Vibrio cholerae, the cholera pathogen, is tolerant to antibiotics targeting cell wall synthesis. In response to a wide variety of cell wall- acting ...

  1. 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.

  2. Structure of polysaccharide antibiotics

    International Nuclear Information System (INIS)

    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)

  3. Generation and characterization of soybean and marker-free tobacco plastid transformants over-expressing a bacterial 4-hydroxyphenylpyruvate dioxygenase which provides strong herbicide tolerance.

    Science.gov (United States)

    Dufourmantel, Nathalie; Dubald, Manuel; Matringe, Michel; Canard, Hélène; Garcon, Frédéric; Job, Claudette; Kay, Elisabeth; Wisniewski, Jean-Pierre; Ferullo, Jean-Marc; Pelissier, Bernard; Sailland, Alain; Tissot, Ghislaine

    2007-01-01

    Plant 4-hydroxyphenylpyruvate dioxygenase (HPPD) is part of the biosynthetic pathway leading to plastoquinone and vitamin E. This enzyme is also the molecular target of various new bleaching herbicides for which genetically engineered tolerant crops are being developed. We have expressed a sensitive bacterial hppd gene from Pseudomonas fluorescens in plastid transformants of tobacco and soybean and characterized in detail the recombinant lines. HPPD accumulates to approximately 5% of total soluble protein in transgenic chloroplasts of both species. As a result, the soybean and tobacco plastid transformants acquire a strong herbicide tolerance, performing better than nuclear transformants. In contrast, the over-expression of HPPD has no significant impact on the vitamin E content of leaves or seeds, quantitatively or qualitatively. A new strategy is presented and exemplified in tobacco which allows the rapid generation of antibiotic marker-free plastid transformants containing the herbicide tolerance gene only. This work reports, for the first time, the plastome engineering for herbicide tolerance in a major agronomic crop, and a technology leading to marker-free lines for this trait. PMID:17207262

  4. Pseudomonas aeruginosa infection in embryonated hen's eggs. An alternative in vivo model for the screening of antibacterial substances.

    Science.gov (United States)

    Härtl, A; Möllmann, U; Schrinner, E; Stelzner, A

    1997-09-01

    Embryonated hens' eggs can be reliably infected by Pseudomonas aeruginosa in laboratory experiments. Therapy tests with the antibiotics azlocillin (CAS 37091-66-0) and gentamicin (CAS 13291-74-2) on this type of infected hens' eggs demonstrate that this test system offers a realistic alternative to septic experiments with small laboratory rodents. Chick embryos survive a lethal Pseudomonas infection when azlocillin or gentamicin in a relevant therapeutic dose are administered immediately after the infective agent. The use of Pseudomonas infected chick embryos in the screening for new antiinfectives allows, therefore, a considerable reduction of the number of laboratory rodents required. PMID:9342424

  5. "Neonatal Sepsis due to Klebsiella: Frequency, Outcome and Antibiotic Sensitivity"

    Directory of Open Access Journals (Sweden)

    E Malakan Rad

    2004-07-01

    Full Text Available Sepsis is a significant cause of morbidity and mortality in neonates. The most common pathogens of bacterial sepsis and antibiotic sensitivity patterns vary in different parts of the world. The aim of this study was to determine the most common pathogens and outcome of neonatal sepsis and also antibiotic sensitivity patterns of Klebsiella species. A retrospective descriptive study was carried out. The study was performed at a neonatal care unit in Kashan between October 2000 to October 2003.Only those neonates with positive blood culture were included. Patients with Klebsiella septicemia were categorized into two groups of early and late-onset sepsis. Patterns of the antibiotic resistance of the bacterial isolates were studied by disc diffusion technique. Frequencies and Fisher’s Exact test was used to compare the early-onset outcome versus late –onset outcome. One hundred and thirty –six neonates had positive blood cultures out of 453 cases. The most common pathogens were Pseudomonas, Klebsiella and coagulase negative Staphylococci respectively. Overall crude mortality rate was 39% (Pseudomonas was the predominant cause. All Klebsiella species were resistant to ampicillin. Twenty-three percent of Klebsiella species were multiresistant considering our most common etiologic pathogens of bacterial sepsis and the significant number of resistant bacteria to ampicillin and gentamicin; it seems prudent to consider revising the present choice of empirical antibiotic treatment.

  6. Pseudomonas aeruginosa bacteraemia in two UK district hospitals

    Directory of Open Access Journals (Sweden)

    David A. Enoch

    2013-09-01

    Full Text Available Pseudomonas aeruginosa bacteraemia is associated with significant morbidity and mortality. We retrospectively studied the epidemiology of bacteraemia due to P. aeruginosa in two UK district hospitals so as to determine prevention strategies and assess the efficacy and compliance with local hospital antibiotic guidelines. Eighty six episodes occurred in 85 patients over the 3 year period. There was a year on year increase in bacteraemias, due predominantly to an increased proportion of community-onset episodes. Urinary catheterisation was a significant risk factor, along with anaemia, renal disease, malignancy and diabetes. The antibiotic guidelines were adequate for 92.8% of episodes but only 73.8% of patients received adequate therapy. Failure to follow the guidelines was principally due to unwillingness to use gentamicin due to concerns about nephrotoxicity. The antibiotic guidelines may need reviewing to accommodate this problem and further work is required to address urinary catheter care in both the hospital and community. Pseudomonas aeruginosa should be considered a significant pathogen when patients are admitted with features of sepsis.

  7. 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.

  8. 40 CFR 180.1108 - Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Delta endotoxin of Bacillus thuringiensis variety San Diego encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. 180.1108 Section 180.1108 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS TOLERANCES...

  9. 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.

  10. The future of antibiotics.

    Science.gov (United States)

    Spellberg, Brad

    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

  11. Immunomodulatory actions of antibiotics

    Directory of Open Access Journals (Sweden)

    Minić Svetlana

    2009-01-01

    Full Text Available Introduction. Antimicrob drugs and immune system interaction has been studied since the pioneer works of Metchnikoff. After the introduction of antibiotics in clinical practice this area has attracted little attention of investigators, because of the lack of standards. This is the reason that the studying of the influence of antibiotics on immune system is still at its beginning. Aim: To point out the immunomodulatory action of some antibiotics on certain components of immune system. Methods and results. The literaure findings show that antibiotics exspress immunomodulatory action on some components of immune system such as fagocytes (polymorphonucleary, macrophages, monocytes, cytokines, immunoglobulines, and on cellular immunity. The principles of antibiotics action on phagocyte are the inhibition of chemotaxis and oxidants production. Macrolides applied for a short time enchance the phagocytic functions while their long use leads to immunosupression. Some cephalosporines and rifampicin in therapeutic doses inhibit the oxydative metabolism of macrophages. Tetracyclines, clindamycines, chloramphenicol and tobramycin inhibit the synthesis of superoxyd anione. The action of some antibiotics on cytokine and specific antibodies is also important. Cellular immunity can be affected as well. After administration of certain antibiotics it takes 1-2 weeks to reestablish normal cellular immunity, and for other even more. Conclusion. There is still no clear standing on real effects of antibiotics on the immune system. Clinicians should search for more information from this new-old field of investigation in order to give more adequate therapy to patients.

  12. 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. 

  13. Antibiotic-resistant gram-negative bacterial infections in patients with cancer.

    Science.gov (United States)

    Perez, Federico; Adachi, Javier; Bonomo, Robert A

    2014-11-15

    Patients with cancer are at high risk for infections caused by antibiotic resistant gram-negative bacteria. In this review, we summarize trends among the major pathogens and clinical syndromes associated with antibiotic resistant gram-negative bacterial infection in patients with malignancy, with special attention to carbapenem and expanded-spectrum β-lactam resistance in Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia--all major threats to our cancer patients. Optimal therapy for these antibiotic-resistant pathogens still remains to be determined. PMID:25352627

  14. Influence of antibiotic adsorption on biocidal activities of silver nanoparticles.

    Science.gov (United States)

    Khurana, Chandni; Vala, Anjana K; Andhariya, Nidhi; Pandey, O P; Chudasama, Bhupendra

    2016-04-01

    Excessive use of antibiotics has posed two major challenges in public healthcare. One of them is associated with the development of multi-drug resistance while the other one is linked to side effects. In the present investigation, the authors report an innovative approach to tackle the challenges of multi-drug resistance and acute toxicity of antibiotics by using antibiotics adsorbed metal nanoparticles. Monodisperse silver nanoparticles (SNPs) have been synthesised by two-step process. In the first step, SNPs were prepared by chemical reduction of AgNO3 with oleylamine and in the second step, oleylamine capped SNPs were phase-transferred into an aqueous medium by ligand exchange. Antibiotics - tetracycline and kanamycin were further adsorbed on the surface of SNPs. Antibacterial activities of SNPs and antibiotic adsorbed SNPs have been investigated on gram-positive (Staphylococcus aureus, Bacillus megaterium, Bacillus subtilis), and gram-negative (Proteus vulgaris, Shigella sonnei, Pseudomonas fluorescens) bacterial strains. Synergistic effect of SNPs on antibacterial activities of tetracycline and kanamycin has been observed. Biocidal activity of tetracycline is improved by 0-346% when adsorbed on SNPs; while for kanamycin, the improvement is 110-289%. This synergistic effect of SNPs on biocidal activities of antibiotics may be helpful in reducing their effective dosages. PMID:27074856

  15. Back to the future: evolving bacteriophages to increase their effectiveness against the pathogen Pseudomonas aeruginosa PAO1

    OpenAIRE

    Betts, Alex; Vasse, Marie; Kaltz, Oliver; Hochberg, Michael E.

    2013-01-01

    Antibiotic resistance is becoming increasingly problematic for the treatment of infectious disease in both humans and livestock. The bacterium Pseudomonas aeruginosa is often found to be resistant to multiple antibiotics and causes high patient mortality in hospitals. Bacteriophages represent a potential option to combat pathogenic bacteria through their application in phage therapy. Here, we capitalize on previous studies showing how evolution may increase phage infection capacity relative t...

  16. Characterising novel anti-biofilm targets for the treatment of chronic Pseudomonas aeruginosa infection in the cystic fibrosis lung

    OpenAIRE

    McCarthy, Ronan

    2014-01-01

    The global rise in antibiotic resistance is a significant problem facing healthcare professionals. In particular within the cystic fibrosis (CF) lung, bacteria can establish chronic infection and resistance to a wide array of antibiotic therapies. One of the principle pathogens associated with chronic infection in the CF lung is Pseudomonas aeruginosa. P. aeruginosa can establish chronic infection in the CF lung partly through the use of the biofilm mode of growth. This biofilm mode of growth...

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

    International Nuclear Information System (INIS)

    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)

  18. Antibiotic Susceptibility Testing of the Gram-Negative Bacteria Based on Flow Cytometry.

    Science.gov (United States)

    Saint-Ruf, Claude; Crussard, Steve; Franceschi, Christine; Orenga, Sylvain; Ouattara, Jasmine; Ramjeet, Mahendrasingh; Surre, Jérémy; Matic, Ivan

    2016-01-01

    Rapidly treating infections with adequate antibiotics is of major importance. This requires a fast and accurate determination of the antibiotic susceptibility of bacterial pathogens. The most frequently used methods are slow because they are based on the measurement of growth inhibition. Faster methods, such as PCR-based detection of determinants of antibiotic resistance, do not always provide relevant information on susceptibility, particularly that which is not genetically based. Consequently, new methods, such as the detection of changes in bacterial physiology caused by antibiotics using flow cytometry and fluorescent viability markers, are being explored. In this study, we assessed whether Alexa Fluor® 633 Hydrazide (AFH), which targets carbonyl groups, can be used for antibiotic susceptibility testing. Carbonylation of cellular macromolecules, which increases in antibiotic-treated cells, is a particularly appropriate to assess for this purpose because it is irreversible. We tested the susceptibility of clinical isolates of Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa, to antibiotics from the three classes: β-lactams, aminoglycosides, and fluoroquinolones. In addition to AFH, we used TO-PRO®-3, which enters cells with damaged membranes and binds to DNA, and DiBAC4 (3), which enters cells with depolarized membranes. We also monitored antibiotic-induced morphological alterations of bacterial cells by analyzing light scattering signals. Although all tested dyes and light scattering signals allowed for the detection of antibiotic-sensitive cells, AFH proved to be the most suitable for the fast and reliable detection of antibiotic susceptibility. PMID:27507962

  19. NANOTECHNOLOGICAL SOLUTION FOR IMPROVING THE ANTIBIOTIC EFFICIENCY AGAINST BIOFILMS DEVELOPED BY GRAM-NEGATIVE BACTERIAL STRAINS

    Directory of Open Access Journals (Sweden)

    Keng-Shiang Huang

    2013-03-01

    Full Text Available At present bacteria involved in biofilm associated infections display the highest rates of antibiotic resistance among pathogenic bacteria, which made that treatment options to be limited, and determined the researchers to find out alternative treatments to antibiotics. In the recent years nanomaterials gained much attention in medicine, particularly in the fight to bacteria resistant to antibiotics by acting as drug delivery devices. Magnetic iron oxide nanoparticles (MNPs have raised much interest during the recent years due to their potential applications in medicine. In the present study we synthesized MNPd functionalized with antibiotics for the study of their antimicrobial and anti-biofilm properties against Escherichia coli and Pseudomonas aeruginosa, two Gram-negative bacteria, frequently resistant to antibiotics, involved in biofilm infections in order to investigate their capacity to serve as potential drug delivery systems in the fight to these important opportunist pathogens.

  20. Relationship between antibiotic- and disinfectant-resistance profiles in bacteria harvested from tap water.

    Science.gov (United States)

    Khan, Sadia; Beattie, Tara K; Knapp, Charles W

    2016-06-01

    Chlorination is commonly used to control levels of bacteria in drinking water; however, viable bacteria may remain due to chlorine resistance. What is concerning is that surviving bacteria, due to co-selection factors, may also have increased resistance to common antibiotics. This would pose a public health risk as it could link resistant bacteria in the natural environment to human population. Here, we investigated the relationship between chlorine- and antibiotic-resistances by harvesting 148 surviving bacteria from chlorinated drinking-water systems and compared their susceptibilities against chlorine disinfectants and antibiotics. Twenty-two genera were isolated, including members of Paenibacillus, Burkholderia, Escherichia, Sphingomonas and Dermacoccus species. Weak (but significant) correlations were found between chlorine-tolerance and minimum inhibitory concentrations against the antibiotics tetracycline, sulfamethoxazole and amoxicillin, but not against ciprofloxacin; this suggest that chlorine-tolerant bacteria are more likely to also be antibiotic resistant. Further, antibiotic-resistant bacteria survived longer than antibiotic-sensitive organisms when exposed to free chlorine in a contact-time assay; however, there were little differences in susceptibility when exposed to monochloramine. Irrespective of antibiotic-resistance, spore-forming bacteria had higher tolerance against disinfection compounds. The presence of chlorine-resistant bacteria surviving in drinking-water systems may carry additional risk of antibiotic resistance. PMID:26966812

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

    Science.gov (United States)

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

    2012-05-01

    A bacterial isolate from Mandovi estuary Goa, India, which can resist 0.6mM lead nitrate in Tris-buffered minimal medium was identified as Pseudomonas aeruginosa and designated as strain WI-1. PCR amplification clearly revealed presence of bmtA gene encoding bacterial metallothionein responsible for metal sequestration and AAS analysis proved intracellular bioaccumulation of 26.5mg lead/gram dry weight of cells. SDS-PAGE analysis confirmed lead induced bacterial metallothionein with molecular weight 11 kDa, which corresponds to the predicted bmtA gene. Significant growth inhibition of phytopathogenic fungi Fusarium oxysporum NCIM 1008 by siderophore-rich culture supernatant was also observed. Pot experiment with Pisum sativum L inoculated with this strain revealed higher seed germination percentage and significant growth promotion than uninoculated seeds in a soil amended with 7.704 g/kg lead, which indicates amelioration of lead toxicity. This lead resistant strain showed cross tolerance to cadmium, mercury and Tributyltin chloride (TBTC) along with resistance to multiple antibiotics. PMID:22284824

  2. 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

  3. Targeting Antibiotic Resistance.

    Science.gov (United States)

    Chellat, Mathieu F; Raguž, Luka; Riedl, Rainer

    2016-06-01

    Finding strategies against the development of antibiotic resistance is a major global challenge for the life sciences community and for public health. The past decades have seen a dramatic worldwide increase in human-pathogenic bacteria that are resistant to one or multiple antibiotics. More and more infections caused by resistant microorganisms fail to respond to conventional treatment, and in some cases, even last-resort antibiotics have lost their power. In addition, industry pipelines for the development of novel antibiotics have run dry over the past decades. A recent world health day by the World Health Organization titled "Combat drug resistance: no action today means no cure tomorrow" triggered an increase in research activity, and several promising strategies have been developed to restore treatment options against infections by resistant bacterial pathogens. PMID:27000559

  4. 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....

  5. Antibiotic induced meningitis.

    OpenAIRE

    1994-01-01

    Three patients with antibiotic induced meningitis, one following penicillin with seven episodes, are reported on--the first well documented description of penicillin induced meningitis. In this patient episodes of headache and nuchal rigidity appeared with and without CSF pleocytosis. Two patients had a total of five episodes of antibiotic induced meningitis after trimethoprim-sulphamethoxazole (co-trimoxazole) administration. The features common to all three patients were myalgia, confusion ...

  6. Antibiotic Precautions in Athletes

    OpenAIRE

    Fayock, Kristopher; Voltz, Matthew; Sandella, Bradley; Close, Jeremy; Lunser, Matthew; Okon, Joshua

    2014-01-01

    Context: Antibiotics are the mainstay of treatment for bacterial infections in patients of all ages. Athletes who maximally train are at risk for illness and various infections. Routinely used antibiotics have been linked to tendon injuries, cardiac arrhythmias, diarrhea, photosensitivity, cartilage issues, and decreased performance. Evidence Acquisition: Relevant articles published from 1989 to 2012 obtained through searching MEDLINE and OVID. Also, the Food and Drug Administration website w...

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

    Directory of Open Access Journals (Sweden)

    Hamid Reza Goli

    2016-03-01

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

  8. Effect of Pseudomonas aeruginosa Pure Exotoxin A on Mice WBC in Comparison with Human WBC Contaminated by Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    M Naghmachi

    2008-12-01

    Full Text Available ABSTRACT Introduction & Objective: Pseudomonas aeruginosa is a gram negative bacterial. This bacterium is resistant to many antibiotics and chemical disinfectants. Pseudomonas aeruginosa is an opportunistic bacteria and caused infection in skin, external ear, upper respiratory tract, large intestine and is an important bacteria in nosocomial infections. It causes acute infection in burn disease. This bacterium can produce exotoxin A and effect on elongation factor II and can stop protein synthesis. The aim of this study was to evaluate the effect of exotoxin A on mice WBC and comparison of the results with human WBC that contaminated with Pseudomonas aeruginosa. Materials & Methods: This is an experimental study which was conducted in 1384 on burn disease patients referred to Shiraz Ghotbodin hospital. Sample that contaminated with PA was taken from these patients for WBC count and WBC differentiation. Sample was also taken from 100 burn patients without infection (50 male and 50 female. Toxigenic strain of PA103 was cultured on liquid media and used for purification of exotoxin A. This sample was injected to 50 mice (I.V and after different incubation time, WBC was counted. Ten normal mice was used as control. Collected data analyzed by SPSS. Results: WBC count decreased in mice that received Pseudomonas aeruginosa exotoxin A in comparison with normal mice (P<0.05. WBC count was significantly decreased in burn patients in comparison with normal individuals (P<0.029 and most decrease was belonged to PMN. Conclusion: The results demonstrated that Pseudomonas aeruginosa that produce exotoxin induce WBC decrease in burn disease and also in mice that contaminated with exotoxin of this bacteria. It can be concluded that bacterial infection in burn patients is toxigenic strain of PA that produce exotoxin A.

  9. [Analysis of antibiotic usage].

    Science.gov (United States)

    Balpataki, R; Balogh, J; Zelkó, R; Vincze, Z

    2001-01-01

    Economic analysis is founded on the assumption that resources are limited and that should be used in a way that maximizes the benefits gained. Pharmacoeconomics extends these assumptions to drug treatment. Therefore, a full pharmacoeconomic analysis must consider two or more alternative treatments and should be founded on measurement of incremental cost, incremental efficacy, and the value of successful outcome. Antibiotic policy based only on administrative restrictions is failed, instead of it disease formularies and infectologist consultation system are needed. Equally important are various programmes that encourage the cost-conscious use of the antibiotics chosen. Some of the methods evaluated in the literature include: streamlining from combination therapy to a single agent, early switching from parenteral to oral therapy, initiating treatment with oral agents, administering parenteral antibiotic at home from outset of therapy, and antibiotic streamlining programmes that are partnered with infectious disease physicians. The solution is the rational and adequate use of antibiotics, based on the modern theory and practice of antibiotic policy and infection control, that cannot be carried out without the activities of experts in this field. PMID:11769090

  10. 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.

  11. [Prophylactic antibiotics in neurosurgery].

    Science.gov (United States)

    Iacob, G; Iacob, Simona; Cojocaru, Inimioara

    2007-01-01

    Because of a low risk of infection (around 2-3%), prophylactic use of antibiotics in neurosurgery is a controversial issue. Some neurosurgeons consider that there are strong arguments against the use of antimicrobials (promotion of antibiotic-resistant strains of bacteria, superinfection and adverse drug reactions) and meticulous aseptic techniques could be more usefully than prophylactic antibiotics. On the other hand, despite of being rare, the consequences of a neurosurgical infection can be dramatic and may result in a rapid death, caused by meningitis, cerebritis, abscess formation or sepsis. Clinical studies emphasized that the most important factors influencing the choice of antibiotic prophylaxis in neurosurgery is the patient's immune status, virulence of the pathogens and the type of surgery ("clean contaminated"--procedure that crosses the cranial sinuses, "clean non-implant"--procedure that does not cross the cranial sinuses, CSF shunt surgery, skull fracture). Prophylaxis has become the standard of care for contaminated and clean-contaminated surgery, also for surgery involving insertion of artificial devices. The antibiotic (first/second generation of cephalosporins or vancomycin in allergic patients) should recover only the cutaneous possibly contaminating flora (S. aureus, S. epidermidis) and should be administrated 30' before the surgical incision, intravenously in a single dose. Most studies pointed that identification of the risk factors for infections, correct asepsis and minimal prophylactic antibiotic regimen, help neurosurgeons to improve patient care and to decrease mortality without selecting resistant bacteria. PMID:18293694

  12. 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

    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...

  13. Identification of Five Structurally Unrelated Quorum-Sensing Inhibitors of Pseudomonas aeruginosa from a Natural-Derivative Database

    DEFF Research Database (Denmark)

    Tan, Sean Yang-Yi; Chua, Song-Lin; Chen, Yicai;

    2013-01-01

    (QSIs), have been shown to effectively block QS and subsequently attenuate the virulence of Pseudomonas aeruginosa, as well as increasing its susceptibility to both antibiotics and the immune system. In this study, a structure-based virtual screening (SB-VS) approach was used for the discovery of novel...

  14. Complete Genome Sequence of Pseudomonas fluorescens LBUM636, a Strain with Biocontrol Capabilities against Late Blight of Potato.

    Science.gov (United States)

    Morrison, Christopher K; Novinscak, Amy; Gadkar, Vijay J; Joly, David L; Filion, Martin

    2016-01-01

    Herein provided is the full-genome sequence of Pseudomonas fluorescens LBUM636. This strain is a plant growth-promoting rhizobacterium (PGPR) which produces phenazine-1-carboxylic acid, an antibiotic involved in the biocontrol of numerous plant pathogens, including late blight of potato caused by the plant pathogen Phytophthora infestans. PMID:27231373

  15. 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.

  16. Antibacterial quality of some antibiotics available in five administrative areas along the national borders of Tanzania

    Directory of Open Access Journals (Sweden)

    Mwambete KD

    2014-12-01

    Full Text Available Kennedy D Mwambete Department of Pharmaceutical Microbiology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania Introduction: In developing countries like Tanzania, bacterial infections are becoming increasingly difficult to treat with available antibiotics. Poor quality antibiotics jeopardize the management of bacterial infections and contribute to the development of antibiotic resistance. Poor storage and harsh tropical climatic conditions accelerate deterioration of antibiotics. Hence, this study investigated the antibacterial effect of antibiotics available in five administrative regions along the national borders of Tanzania. Materials and methods: A cross-sectional study involved the purchase of antibiotics from the Mwanza, Arusha, Kilimanjaro, Mbeya, and Kagera administrative regions. The Kirby–Bauer disk diffusion method was employed to assess antibacterial effects of the antibiotics against Salmonella typhi, Klebsiella spp., Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Inhibition zones (IZ were determined as previously described. Analysis of variance was used to examine the IZ measured using test antibiotics to their respective control antibiotics; differences were considered significant at P<0.05. Results: Seventy-six antibiotic samples from 22 manufacturers were tested. Six antibiotic samples were from anonymous manufacturers and 29 antibiotic samples had no manufacturing or expiration dates. Different samples of the same antibiotics produced variable results. IZ measured using different samples of ampicillin (AMP and ciprofloxacin and their control antibiotics revealed significant differences when tested against S. typhi (P<0.05. Samples of tetracycline and chloramphenicol resulted in IZ comparable to their controls against S. typhi. All samples of AMP yielded comparable IZ on Klebsiella spp., whereas samples of chloramphenicol and tetracycline exerted IZ against P. aeruginosa that

  17. 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.

  18. Antibiotic Susceptibility and Immunomodulatory Potential of Chosen Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    M. Sujatha

    2010-01-01

    Full Text Available Problem statement: Antibiotic susceptibility is still the best way for bacterial pathogen escape mechanism against immunity. Approach: In the present investigation, bacterial pathogens like Staphylococcus aureus, Escherichia coli, Aeromonas hydrophila, Klebsiella and Pseudomonas aeruginosa were used to screen antibiotic susceptibility and immunomodulatory potential. Results: All the test pathogens were sensitive to all the test antibiotics 11±2 mm except penicillin. The conditions for the preparation of antigens of intact natural composition and conformation from pathogens (whole cell and heat killed, were determined using Swiss albino mice (Balb/C as experimental species. Immunomodulatory potential of test pathogens were screened using animal model. Test pathogen decreases the body weight comparing that of normal mice, some notable changes were also noted in activity, growth, water consumption, feed consumption. Antibody titre level in animal serum decreased upto 50% in whole cell pathogen and heat killed pathogen treated animals. Conclusion: The five pathogens administered animals, decrement in B-lymphocyte was much pronounced in Pseudomonas aeruginosa followed by Escherichia coli, Staphylococcus aureus, Klebsiella sp., Aeromonas hydrophila in the 5 week. Pathogen treated mice showed an IgG suppressive effect. It is found to be suppressive to T cell production, so induction in cell mediated immunity has confirmed pathogenic potential of test pathogens. All these test pathogenic strains were remarkably suppressing immune system of pathogen exposed animals.

  19. [Meningoencephalitis caused by Pseudomonas cepacia].

    Science.gov (United States)

    Pérez Monrás, Miriam Fina; Batlle Almodóvar, María del Carmen; González, Cernero; Tamargo Martínez, Isis; Meneses, Félix Dickinson

    2006-01-01

    A case of meningoencephalitis of bacterial etiology caused by Pseudomonas cepacia was described. The strain was received at the Reference Laboratory of Bacterial Acute Respiratory Infections of "Pedro Kouri" Institute of Tropical Medicine, where its microbiological identification was confirmed. This isolation was a finding in an adult immunocompetent patient. The evolution was favourable with no sequelae for his future life. Pseudomona cepacia has been associated with respiratory infections in patients with cystic fibrosis. Patients with Pseudomonas cepacia may be asymptomatic or present fatal acute and fulminant infection. PMID:23427437

  20. Complete Genome of the Plant Growth-Promoting Rhizobacterium Pseudomonas putida BIRD-1▿

    OpenAIRE

    Matilla, Miguel A.; Pizarro-Tobias, Paloma; Roca, Amalia; Fernández, Matilde; Duque, Estrella; Molina, Lázaro; WU, XIAO; van der Lelie, Daniel; Gómez, Manuel J.; Segura, Ana; Ramos, Juan-Luis

    2010-01-01

    We report the complete sequence of the 5.7-Mbp genome of Pseudomonas putida BIRD-1, a metabolically versatile plant growth-promoting rhizobacterium that is highly tolerant to desiccation and capable of solubilizing inorganic phosphate and iron and of synthesizing phytohormones that stimulate seed germination and plant growth.

  1. Complete Genome of the Plant Growth-Promoting Rhizobacterium Pseudomonas putida BIRD-1

    Energy Technology Data Exchange (ETDEWEB)

    Matilla, M.A.; van der Lelie, D.; Pizarro-Tobias, P.; Roca, A.; Fernandez, M.; Duque, E.; Molina, L.; Wu, X.; Gomez, M. J.; Segura, A.; Ramos, J.-L.

    2011-03-01

    We report the complete sequence of the 5.7-Mbp genome of Pseudomonas putida BIRD-1, a metabolically versatile plant growth-promoting rhizobacterium that is highly tolerant to desiccation and capable of solubilizing inorganic phosphate and iron and of synthesizing phytohormones that stimulate seed germination and plant growth.

  2. Gene expression profiling in viable but not culturable (VBNC) cells of Pseudomonas syringae pv syringae

    Science.gov (United States)

    Gram-negative bacterium Pseudomonas syringae infects diverse crop plants and comprises at least 50 different pathovar strains with different host ranges. One of our objectives is related to understanding molecular mechanisms of stress tolerance in alfalfa, the most widely grown forage crop in the wo...

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

    Science.gov (United States)

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

    2016-03-01

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

  4. 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. PMID:27216077

  5. Fibrin sealant as a carrier for sustained delivery of antibiotics

    Directory of Open Access Journals (Sweden)

    Selçuk Kara

    2014-06-01

    Full Text Available Objective: To evaluate the activity and sustained release of antibiotics from fibrin sealant against common strains of ocular bacteria. Methods: Vancomycin, ceftazidime, moxifloxacin and lomefloxacin were incorporated into fibrin sealant in the shape of discs. Each antibiotic disc and control fibrin disc without drug was tested in vitro against standard bacterial strains of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae and Pseudomonas aeroginosa. After 24 hours of incubation at 37 °C, the discs were transferred to new plates of bacteria and triplicated for each antibiotic. Results: All antibiotic discs demonstrated detectable activity after 24 hours. Vancomycin had the longest duration of activity (4 days on the S. pneumonia grown plate. The moxifloxacin discs showed a prolonged inhibition of S. aureus and S. pneumonia for 3 days and inhibited the other strains for 2 days. Conclusion: Fibrin sealants provided prolonged drug delivery, which indicates that antibiotic-loaded fibrin clots could be useful for early ocular postoperative care and treatment. J Clin Exp Invest 2014; 5 (2: 194-199

  6. Antibiotic Therapy in Pyogenic Meningitis in Paediatric Patients

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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

  8. 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. PMID:25227297

  9. 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

    Directory of Open Access Journals (Sweden)

    Mainz JG

    2014-02-01

    Full Text Available Jochen G Mainz,1 Katja Schädlich,1 Claudia Schien,1 Ruth Michl,1 Petra Schelhorn-Neise,2 Assen Koitschev,3 Christiane Koitschev,4 Peter M Keller,5 Joachim Riethmüller,6 Baerbel Wiedemann,7 James F Beck1 1Cystic Fibrosis Centre, Department of Pediatrics, Jena University Hospital, Jena, Germany; 2Otorhinolaryngology Department, Jena University Hospital, Jena, Germany; 3Otorhinolaryngology Department, Klinikum Stuttgart, Germany; 4Otorhinolaryngology Department, University Hospital, Tübingen, Germany; 5Microbiology, Jena University Hospital, Jena, Germany; 6University Hospital, Pediatric CF-Centre, Tübingen, Germany; 7Technical University, Biometrics, Dresden, Germany 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

  10. 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...

  11. Treatment of pseudomonas and Staphylococcus bronchopulmonary infection in patients with cystic fibrosis.

    Science.gov (United States)

    Das, Rashmi Ranjan; Kabra, Sushil Kumar; Singh, Meenu

    2013-01-01

    The optimal antibiotic regimen is unclear in management of pulmonary infections due to pseudomonas and staphylococcus in cystic fibrosis (CF). We systematically searched all the published literature that has considered the evidence for antimicrobial therapies in CF till June 2013. The key findings were as follows: inhaled antipseudomonal antibiotic improves lung function, and probably the safest/most effective therapy; antistaphylococcal antibiotic prophylaxis increases the risk of acquiring P. aeruginosa; azithromycin significantly improves respiratory function after 6 months of treatment; a 28-day treatment with aztreonam or tobramycin significantly improves respiratory symptoms and pulmonary function; aztreonam lysine might be superior to tobramycin inhaled solution in chronic P. aeruginosa infection; oral ciprofloxacin does not produce additional benefit in those with chronic persistent pseudomonas infection but may have a role in early or first infection. As it is difficult to establish a firm recommendation based on the available evidence, the following factors must be considered for the choice of treatment for each patient: antibiotic related (e.g., safety and efficacy and ease of administration/delivery) and patient related (e.g., age, clinical status, prior use of antibiotics, coinfection by other organisms, and associated comorbidities ones). PMID:24489509

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

    Science.gov (United States)

    Abbas, Hisham A

    2015-01-01

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

  13. Colonization and plant growth promoting characterization of endophytic Pseudomonas chlororaphis strain Zong1 isolated from Sophora alopecuroides root nodules

    Directory of Open Access Journals (Sweden)

    Long Fei Zhao

    2013-01-01

    Full Text Available The endophytic strain Zong1 isolated from root nodules of the legume Sophora alopecuroides was characterized by conducting physiological and biochemical tests employing gfp-marking, observing their plant growth promoting characteristics (PGPC and detecting plant growth parameters of inoculation assays under greenhouse conditions. Results showed that strain Zong1 had an effective growth at 28 ºC after placed at 4-60 ºC for 15 min, had a wide range pH tolerance of 6.0-11.0 and salt tolerance up to 5% of NaCl. Zong1 was resistant to the following antibiotics (µg/mL: Phosphonomycin (100, Penicillin (100 and Ampicillin (100. It could grow in the medium supplemented with 1.2 mmol/L Cu, 0.1% (w/v methylene blue and 0.1-0.2% (w/v methyl red, respectively. Zong1 is closely related to Pseudomonas chlororaphis based on analysis the sequence of 16S rRNA gene. Its expression of the gfp gene indicated that strain Zong1 may colonize in root or root nodules and verified by microscopic observation. Furthermore, co-inoculation with Zong1 and SQ1 (Mesorhizobium sp. showed significant effects compared to single inoculation for the following PGPC parameters: siderophore production, phosphate solubilization, organic acid production, IAA production and antifungal activity in vitro. These results suggest strains P. chlororaphi Zong1 and Mesorhizobium sp. SQ1 have better synergistic or addictive effect. It was noteworthy that each growth index of co-inoculated Zong1+SQ1 in growth assays under greenhouse conditions is higher than those of single inoculation, and showed a significant difference (p < 0.05 when compared to a negative control. Therefore, as an endophyte P. chlororaphis Zong1 may play important roles as a potential plantgrowth promoting agent.

  14. Ecological antibiotic policy.

    Science.gov (United States)

    Høiby, N

    2000-09-01

    Development of resistance to antibiotics is a major problem worldwide. The normal oropharyngeal flora, the intestinal flora and the skin flora play important roles in this development. Within a few days after the onset of antibiotic therapy, resistant Escherichia coli, Haemophilus influenzae and Staphylococcus epidermidis can be detected in the normal flora of volunteers or patients. Horizontal spread of the resistance genes to other species, e.g. Salmonella spp., Staphylococcus aureus and Streptococcus pneumoniae, occurs by conjugation or transformation. An ecologically sound antibiotic policy favours the use of antibiotics with little or no impact on the normal flora. Prodrug antibiotics which are not active against the bacteria in the mouth and the intestine (before absorption) and which are not excreted to a significant degree via the intestine, saliva or skin are therefore preferred. Prodrugs such as pivampicillin, bacampicillin, pivmecillinam and cefuroxime axetil are favourable from an ecological point of view. Experience from Scandinavia supports this, since resistance to mecillinam after 20 years of use is low (about 5%) and stable. PMID:11051626

  15. Rifaximin for maintenance therapy in antibiotic-dependent pouchitis

    Directory of Open Access Journals (Sweden)

    Lopez A Rocio

    2008-06-01

    Full Text Available Abstract Background Pouchitis is the most common long-term complication of in patients with restorative proctocolectomy and ileal pouch-anal anastomosis. Patients often develop antibiotic-dependent form of pouchitis requiring long-term antibiotic therapy for remission maintenance. Rifaximin, an oral, non-systemic, broad-spectrum antibiotic with a favorable safety profile, may be a promising candidate agent for maintenance therapy. This historical cohort open-label study investigated the efficacy and tolerability of rifaximin in maintaining symptomatic and endoscopic remission in patients with antibiotic-dependent pouchitis. Methods Adult patients with antibiotic-dependent pouchitis received a 2-week course of various antibiotics for induction of remission. Patients in remission then began maintenance therapy with rifaximin 200 mg/day (to 1800 mg/day for up to 24 months. Pouchitis Disease Activity Index symptom scores were assessed every 1–3 months to evaluate efficacy. Results Fifty-one patients began maintenance therapy with rifaximin (median dose 200 mg/day; 33 (65% maintained remission through 3 months (primary endpoint. Of these 33 patients, 26 (79% successfully continued maintenance for 6 months after beginning maintenance, 19 (58% successfully continued for 12 months, and two (6% successfully continued for 24 months. Only one patient reported an adverse event (transient facial rash. Conclusion Patients' response to rifaximin as a maintenance therapy appears to be favorable in this open-labeled trial of antibiotic-dependent pouchitis. Randomized, placebo-controlled trials with a longer follow-up are warranted.

  16. Rifaximin for maintenance therapy in antibiotic-dependent pouchitis

    Science.gov (United States)

    Shen, Bo; Remzi, Feza H; Lopez, A Rocio; Queener, Elaine

    2008-01-01

    Background Pouchitis is the most common long-term complication of in patients with restorative proctocolectomy and ileal pouch-anal anastomosis. Patients often develop antibiotic-dependent form of pouchitis requiring long-term antibiotic therapy for remission maintenance. Rifaximin, an oral, non-systemic, broad-spectrum antibiotic with a favorable safety profile, may be a promising candidate agent for maintenance therapy. This historical cohort open-label study investigated the efficacy and tolerability of rifaximin in maintaining symptomatic and endoscopic remission in patients with antibiotic-dependent pouchitis. Methods Adult patients with antibiotic-dependent pouchitis received a 2-week course of various antibiotics for induction of remission. Patients in remission then began maintenance therapy with rifaximin 200 mg/day (to 1800 mg/day) for up to 24 months. Pouchitis Disease Activity Index symptom scores were assessed every 1–3 months to evaluate efficacy. Results Fifty-one patients began maintenance therapy with rifaximin (median dose 200 mg/day); 33 (65%) maintained remission through 3 months (primary endpoint). Of these 33 patients, 26 (79%) successfully continued maintenance for 6 months after beginning maintenance, 19 (58%) successfully continued for 12 months, and two (6%) successfully continued for 24 months. Only one patient reported an adverse event (transient facial rash). Conclusion Patients' response to rifaximin as a maintenance therapy appears to be favorable in this open-labeled trial of antibiotic-dependent pouchitis. Randomized, placebo-controlled trials with a longer follow-up are warranted. PMID:18573211

  17. 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 solvents on mic

  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. Suppression of damping-off in maize seedlings by Pseudomonas corrugata.

    Science.gov (United States)

    Pandey, A; Palni, L M; Hebbar, K P

    2001-01-01

    Two strains of Pseudomonas corrugata, (1 and 7), isolated from subtropical and temperate soils in Sikkim Himalaya, respectively, were subjected to Petri-dish as well as plant-based bioassay to examine their potential for disease suppression against three major pathogens of maize. A mixture of Pythium ultimum, P. arrhenomanes and Fusarium graminearum was introduced in the soil; maize seed inoculated with one of the two strains of Pseudomonas corrugata (1 or 7) were sown in pots containing such soil. The bacterial inoculation resulted in significant disease suppression as well as growth promotion of seedlings. The bacterial strains were also evaluated for their intrinsic antibiotic resistance against a range of concentrations of ten antibiotics. While the bacteria were found to be sensitive to gentamycin and rifampicin, they exhibited resistance against ampicillin, carbenicillin and penicillin, even at high concentrations. PMID:11572460

  20. 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

  1. Identification of KPC-Producing Pseudomonas Aeruginosa and Acinetobacter Baumanniiin a Burned Infant: A Case Report

    Directory of Open Access Journals (Sweden)

    Abdolaziz Rastegar Lari

    2012-03-01

    Full Text Available The objective of this study was to determine the phenotypic characteristics of KPC-producing Pseudomonas aeruginosa and Acinetobacter baumannii isolates. A case report study was performed at a tertiary burn care centre in Tehran, Iran. Nine isolates of Pseudomonas aeruginosa and Acinetobacter baumannii from a hospitalized case were isolated. The identity of isolates was confirmed and their antibiotic susceptibility testing was performed. Eight out of nine Pseudomonas aeruginosa and Acinetobacter baumannii isolates were resistant to Imipenem. Three out of 8 imipenem resistant isolates were also positive for KPC test. Findings of this study highlight the importance of implementation of an effective infection control strategy in order to prevent and reduce the emergence and spread of gram negative Carbapenemase-producing organisms in Iran.

  2. OCULAR INFECTIONS: RATIONAL APPROACH TO ANTIBIOTIC THERAPY

    Directory of Open Access Journals (Sweden)

    Mulla Summaiya A

    2012-02-01

    Full Text Available Background: Isolation of common pathogens involved in ocular infection and their in-vitro susceptibility to commonly used ocular antibiotics, as well as the trends in antibiotic resistance developed by these pathogens were investigated. Material/Methods: All patients with suspected bacterial ocular infections presenting between march 2010 and feb 2011 were examined under slit lamp microscope and samples were collected by using aseptic techniques. All samples were processed for direct microscopy, culture and identification by standard methods. Susceptibility testing was done by Kirby-Bauer method as per CLSI guideline. Results: Out of 116 patients with ocular infections 130 samples were collected, from which 38 different organisms were isolated. Gram-positive cocci 21 (55%, gram-negative cocco-bacilli 5(31% and gram-negative bacilli 12 (32% were isolated. Coagulase negative Staphylococci (37% and Pseudomonas species (21% were the most commonly-isolated. Gatifloxacin has highest efficacy (89% against all isolates. Majority of gram positive cocci were susceptible to vancomycin, gatifloxacin, cefazolin, gram negative cocco-bacilli to amikacin, tobramycin, fluoroquinolone and gram negative bacilli to gatifloxacin. Conclusion: Majority of ocular infection is caused by gram positive organisms which were susceptible to vancomycin followed by gram negative organisms susceptible to amikacin, fluoroquinolone, gram negative cocco-bacilli to amikacin and tobramycin, and gatifloxacin effective against both type of organisms. The information provided in this article help the clinician in formulating rationale-based empirical antibiotic treatment of bacterial ocular infections. [National J of Med Res 2012; 2(1.000: 22-24

  3. Pseudomonas aeruginosa biofilms exposed to imipenem exhibit changes in global gene expression and beta-lactamase and alginate production

    DEFF Research Database (Denmark)

    Bagge, N.; Schuster, M.; Hentzer, Morten;

    2004-01-01

    The lungs of cystic fibrosis (CF) patients are commonly colonized with Pseudomonas aeruginosa biofilms. Chronic endobronchial P. aeruginosa infections are impossible to eradicate with antibiotics, but intensive suppressive antibiotic therapy is essential to maintain the lung function of CF patients....... The treatment often includes beta-lactam antibiotics. How these antibiotics influence gene expression in the surviving biofilm population of P. aeruginosa is not clear. Thus, we used the microarray technology to study the effects of subinhibitory concentrations of a beta-lactam antibiotic, imipenem......, on gene expression in biofilm populations. Many genes showed small but statistically significant differential expression in response to imipenem. We identified 34 genes that were induced or repressed in biofilms exposed to imipenem more than fivefold compared to the levels of induction or repression...

  4. 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 ...

  5. Selective trihydroxyazepane NagZ inhibitors increase sensitivity of Pseudomonas aeruginosa to β-lactams.

    Science.gov (United States)

    Mondon, Martine; Hur, Soo; Vadlamani, Grishma; Rodrigues, Prerana; Tsybina, Polina; Oliver, Antonio; Mark, Brian L; Vocadlo, David J; Blériot, Yves

    2013-12-01

    AmpC β-lactamase confers resistance to β-lactam antibiotics in many Gram negative bacteria. Inducible expression of AmpC requires an N-acetylglucosaminidase termed NagZ. Here we describe the synthesis and characterization of hydroxyazepane inhibitors of NagZ. We find that these inhibitors enhance the susceptibility of clinically relevant Pseudomonas aeruginosa to β-lactams. PMID:24136176

  6. Glutathione exhibits antibacterial activity and increases tetracycline efficacy against Pseudomonas aeruginosa

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Glutathione(GSH) plays important roles in pulmonary diseases,and inhaled GSH therapy has been used to treat cystic fibrosis(CF) patients in clinical trials.The results in this report revealed that GSH altered the sensitivity of Pseudomonas aeruginosa to different antibiotics through pathways unrelated to the oxidative stress as generally perceived.In addition,GSH and its oxidized form inhibited the growth of P.aeruginosa.

  7. Pseudomonas aeruginosa Forms Biofilms in Acute Infection Independent of Cell-to-Cell Signaling▿ †

    OpenAIRE

    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.

    2007-01-01

    Biofilms are bacterial communities residing within a polysaccharide matrix that are associated with persistence and antibiotic resistance in chronic infections. We show that the opportunistic pathogen Pseudomonas aeruginosa forms biofilms within 8 h of infection in thermally injured mice, demonstrating that biofilms contribute to bacterial colonization in acute infections as well. Using light, electron, and confocal scanning laser microscopy, P. aeruginosa biofilms were visualized within burn...

  8. An outbreak of forty five cases of Pseudomonas aeruginosa acute endophthalmitis after phacoemulsification

    OpenAIRE

    2012-01-01

    PURPOSE: To describe an outbreak of Pseudomonas aeruginosa endophthalmitis post cataract surgery. Clinical findings, treatment and outcome are discussed. METHODS: Clinical charts review of forty-five patients treated for endophthalmitis in a two-day period. The patients underwent primary vitrectomy, anterior chamber irrigation and intravitreous antibiotic injection. Cultures from vitreous and anterior chamber samples were performed in all patients. RESULTS: Forty-five patients (twenty-three m...

  9. Electrolytic Generation of Oxygen Partially Explains Electrical Enhancement of Tobramycin Efficacy against Pseudomonas aeruginosa Biofilm

    OpenAIRE

    Stewart, Philip S.; Wattanakaroon, Wanida; Goodrum, Lu; Fortun, Susana M.; McLeod, Bruce R.

    1999-01-01

    The role of electrolysis products, including protons, hydroxyl ions, reactive oxygen intermediates, oxygen, hydrogen, and heat, in mediating electrical enhancement of killing of Pseudomonas aeruginosa biofilms by tobramycin (the bioelectric effect) was investigated. The log reduction in biofilm viable cell numbers compared to the numbers for the untreated positive control effected by antibiotic increased from 2.88 in the absence of electric current to 5.58 in the presence of electric current....

  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. Inhibitory effect of zinc oxide nanoparticles on pseudomonas aeruginosa biofilm formation

    OpenAIRE

    Mohammad Hassani Sangani; Mahboobeh Nakhaei Moghaddam; Mohammad Mahdi Forghanifard

    2015-01-01

    Objective(s): Bacterial biofilm formation causes many persistent and chronic infections. The matrix protects biofilm bacteria from exposure to innate immune defenses and antibiotic treatments. The purpose of this study was to evaluate the biofilm formation of clinical isolates of Pseudomonas aeruginosa and the activity of zinc oxide nanoparticles (ZnO NPs) on biofilm. Materials and Methods: After collecting bacteria from clinical samples of hospitalized patients, the ability of organisms were...

  12. 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.

  13. Mechanism of Enhanced Activity of Liposome-Entrapped Aminoglycosides against Resistant Strains of Pseudomonas aeruginosa

    OpenAIRE

    Mugabe, Clement; Halwani, Majed; Azghani, Ali O.; Lafrenie, Robert M.; Omri, Abdelwahab

    2006-01-01

    Pseudomonas aeruginosa is inherently resistant to most conventional antibiotics. The mechanism of resistance of this bacterium is mainly associated with the low permeability of its outer membrane to these agents. We sought to assess the bactericidal efficacy of liposome-entrapped aminoglycosides against resistant clinical strains of P. aeruginosa and to define the mechanism of liposome-bacterium interactions. Aminoglycosides were incorporated into liposomes, and the bactericidal efficacies of...

  14. Topical antibiotics in the management of corneal ulcer

    Directory of Open Access Journals (Sweden)

    Reddy P

    1988-01-01

    Full Text Available A total of 82 patients suffering from corneal ulcer were treated with framycetin 0.5%, gentamicin 3 mg./ml, chloramphenicol 0.4% and a neomycin combination containing Polymixin B sulphate 5000 u, neomycin sulphate 1700 u and gramicidin 0.025 mg/mL in a Randomised comparative study. The commonest organism isolated was Staphylococcus followed by Pneumococcus, Streptococcus and Pseudomonas. The in vitro sensitivity of these isolates to framycetin was higher than that to others Framycetin produced both earlier and a greater degree of improvement in mean score of signs and symptoms than the other antibiotics. It can thus be concluded that framycetin has a better profile of antibacterial activity and clinical efficacy than some other commonly used topical antibiotics in the treatment of corneal ulcer.

  15. Laser based enhancement of susceptibility of bacteria to antibiotic

    Science.gov (United States)

    Reznick, Yana; Banin, Ehud; Lipovsky, Anat; Lubart, Rachel; Zalevsky, Zeev

    2012-03-01

    Our objective is to test the effect of pulsed (Q-switched) and continuous wave (CW) laser light at wavelength of 532nm on the viability of free-living stationary phase bacteria with and without gentamicin (an antibiotic) treatment. Free living stationary phase gram negative bacteria (Pseudomonas aeruginosa strain PAO1) was immersed in Luria Broth (LB) solution and exposed to Q-switched and CW lasers with and without the addition of the antibiotic gentamicin. Cell viability was determined at different time points. Laser treatment alone did not reduce cell viability compared to untreated control and the gentamicin treatment alone only resulted in a 0.5 log reduction in the viable count for P. aeruginosa. The combined laser and gentamicin treatment, however, resulted in a synergistic effect and viability was reduced by 8 log's for P. aeruginosa PAO1.

  16. [Antibiotical prophylaxy in gynecology].

    Science.gov (United States)

    Záhumenský, J; Menzlová, E; Zmrhal, J; Kučera, E

    2013-08-01

    Gynecological surgery is considered to be clear with possible contamination by gram-positive cocci from the skin, gram-negatives from the perineum or groins or polymicrobial biocenosis from vagina, depending on the surgical approach. Antibiotical prophylaxy enforces the natural mechanisms of immunity and helps to exclude present infection. There were presented many studies comparing useful effect of prophylaxis in gynecological surgery. The benefits of antibiotical prophylaxy before IUD insertion, before the cervical surgery and before hysteroscopies were not verified. On the other hand the prophylaxy of vaginal surgery including vaginal hysterectomy decreases the number of postoperative febrile complications. The positive influence of prophylaxis before the simple laparoscopy and laparoscopy without bowel injury or the opening of the vagina was not evidently verified. In abdominal hysterectomy the antibiotical prophylaxy decreases the incidence of postoperative complications significantly. The administration of 2 g of cefazolin can be recommended. In procedures taking more than 3 hours the repeated administration of cefazolin is suitable. New urogynecological procedures, using mesh implants, were not sufficiently evaluated as for postoperative infections and the posible antibiotical effect. The presence of implant in possibly non sterile area should be considered as high risc of postoperative complications. PMID:24040985

  17. Antibiotics in interventional radiology

    International Nuclear Information System (INIS)

    The range and number of interventional procedures is rapidly increasing each year. A major complication associated with many procedures is infection, which can result in serious adverse outcomes for the patient. Consequently, antibiotics are amongst the most common pharmaceuticals used by the interventionist, particularly for non-vascular procedures, yet almost no randomized controlled trial data exist to inform our decision when formulating appropriate antibiotic prophylaxis regimens. The purpose of this review is to provide an update on the utilization of antibiotics for common interventional radiology procedures, focusing on timing and duration of antibiotic prophylaxis. - Highlights: • Prophylaxis when necessary should be given immediately prior to the procedure for optimum effect. • Where possible single agents with a narrow spectrum of activity should be used. • Account should be taken of the clinical circumstances of the patient, including surgical history. • Continuous review of agents is necessary, ideally with input from the local microbiology department. • The importance of maximum sterile precautions cannot be overstated

  18. Isolation of an antibiotic producer Pseudomonassp. from the Persian Gulf

    Institute of Scientific and Technical Information of China (English)

    Esmaeil Darabpour; Mohammad Roayaei Ardakani; Hossein Motamedi; Gholamreza Ghezelbash; Mohammad Taghi Ronagh

    2010-01-01

    Objective:To investigate the isolation of marine antibiotic-producing bacteria from the Persian Gulf, as an untapped source for searching new natural antibiotics.Methods: Initially water and sediment samples were collected from 18 study sites in the some northern areas of Persian Gulf. All of the bacterial isolates using Marine Agar 2216 were inoculated into Marine broth and incubated on a rotary shaker at 28 ℃ for 2-7 days. Bioactivity of their ethyl acetate extract was assessed at 100 mg/mL concentration in disc diffusion method against 6 gram-positive and 5 gram-negative bacteria. Synthetic antibiotics were used as control.Results: Altogether, 46 bacterial colonies were isolated. Only one isolate from a marine sediment sample collected at a depth of 10 m, identified asPseudomonas aeruginosa PG-01, was exhibited the capability of antibiotic production. The obtained raw extract from intended bacterium was effective against all tested gram positive bacteria while gram negative bacteria were resistance. Methicillin resisitant Stapuylococcus aureus(MRSA),Streptococcus pyogenes (S. pyogenes),Staphylococcus epidermidis (S. epidermidis) andBacillus cereus (B. cereus) were the most sensitive strains. All of tested pathogens were multidrug resistant. The antibacterial compound from this bacterium was active even at 120 ℃. The optimized temperature and time for antibacterial metabolite production were 37 ℃ and 72 hrs, respectively.Conclusions: Considering the antibacterial effect of Pseudomonas aeruginosaPG-01 especially against MRSA, it can be regarded the intended bacterium as a valuable strain and can give hope for treatment of diseases caused by multidrug resistant bacteria.

  19. Early Antibiotic Treatment in Acute Pancreatitis: More News

    Directory of Open Access Journals (Sweden)

    Jan J De Waele

    2006-07-01

    Full Text Available Early antibiotic treatment still remains a therapeutic challenge in the clinical management of acute pancreatitis and several papers have been published in this field [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]. In particular, the antibiotic of choice in preventing the infection of pancreatic necrosis seems to be imipenem [4, 9, 10, 11, 13]. Subsequently, Manes et al. [15] have reported that meropenem, an antibiotic of the same family as imipenem having considerable stability in the presence of renal dehydropeptidase-I and enhanced activity against gram-negative bacteria including Pseudomonas aeruginosa, has an efficacy similar to imipenem in terms of the incidence of pancreatic infection and extrapancreatic infections. We have previously emphasized that further studies should be carried out to specifically decide on the optimal doses of meropenem in patients with acute pancreatitis and that there is a need for studies which answer the following questions. What should the timing of early antibiotic treatment be?. What are the resistant strains selected by meropenem?. Which are the nosocomial infections and fungal superinfections resulting from this new treatment? [16, 17]. These questions are still open and the study from Manes et al. is welcome to attempt to answer some of the aforementioned questions [18]. In this study, the authors compared antibiotic prophylaxis with early antibiotic treatment started after the demonstration of pancreatic necrosis. They studied 215 consecutive patients with acute pancreatitis who were randomized to either Group A (n=108, who started antibiotic therapy (meropenem 500 mg tid at admission, or Group B (n=107, who received antibiotics after computed tomography showed necrosis. C-reactive protein was determined in all patients within 48 hours from the onset of symptoms and computed tomography was performed in both groups after at least 48 h of hospitalization; the clinical course of disease was also compared

  20. Hot Tub Rash (Pseudomonas Dermatitis/Folliculitis)

    Science.gov (United States)

    ... Español [PDF - 1 page] "Hot Tub Rash" ( Pseudomonas Dermatitis / Folliculitis) If contaminated water comes in contact ... is often caused by infection with the germ Pseudomonas aeruginosa . This germ is common in the environment ( ...

  1. Prevalence of Extended-Spectrum and Metallo β-Lactamase Production in AmpC β-Lactamase Producing Pseudomonas aeruginosa Isolates From Burns

    OpenAIRE

    Rafiee, Roya; Eftekhar, Fereshteh; Tabatabaei, Seyyed Ahmad; Minaee Tehrani, Dariush

    2014-01-01

    Background: Pseudomonas aeruginosa is one of the most common causes of nosocomial infections. Resistance of P. aeruginosa to β-lactam antibiotics may be the result of acquired resistance through mutation and over production of various antibiotic inactivating enzymes. This research aimed to determine the prevalence of extended-spectrum β-lactamases (ESBL) and metallo β-lactamase (MBL) production as well as the presence of their related genes among AmpC β-lactamase producing P. aeruginosa isola...

  2. Reduction of Chromium(VI) by Locally Isolated Pseudomonas sp. C-171

    OpenAIRE

    Rahman, Mujeeb Ur; GUL, Shereen; HAQ, Mohammad Zahoor UL

    2007-01-01

    A strain of Pseudomonas sp. C-171 capable of tolerating hexavalent chromium (Cr+6) up to 2000 ppm as potassium dichromate was isolated from domestic sewage. The Cr+6 reduction was checked by growing the isolated strain in a medium containing potassium dichromate as Cr+6 source. The rate of growth of Pseudomonas sp. C-171 decreased with the increase in Cr+6 concentration of the medium. The maximum rate of chromium reduction was observed during the log phase of bacterium growth. The reduction o...

  3. Biofilm induced tolerance towards antimicrobial peptides.

    Directory of Open Access Journals (Sweden)

    Anders Folkesson

    Full Text Available 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 regulated tolerant subpopulation formation and not caused by a general biofilm property. No significant difference in survival was detected when the strains were challenged with ciprofloxacin. Our data show that biofilm formation confers increased colistin tolerance to cells within the biofilm structure, but the protection is conditional being dependent on the structural organization of the biofilm, and the induction of specific tolerance mechanisms.

  4. An alternative physiological role for the EmhABC efflux pump in Pseudomonas fluorescens cLP6a

    Directory of Open Access Journals (Sweden)

    Adebusuyi Abigail A

    2011-11-01

    Full Text Available Abstract Background Efflux pumps belonging to the resistance-nodulation-division (RND superfamily in bacteria are involved in antibiotic resistance and solvent tolerance but have an unknown physiological role. EmhABC, a RND-type efflux pump in Pseudomonas fluorescens strain cLP6a, extrudes hydrophobic antibiotics, dyes and polycyclic aromatic hydrocarbons including phenanthrene. The effects of physico-chemical factors such as temperature or antibiotics on the activity and expression of EmhABC were determined in order to deduce its physiological role(s in strain cLP6a in comparison to the emhB disruptant strain, cLP6a-1. Results Efflux assays conducted with 14C-phenanthrene showed that EmhABC activity is affected by incubation temperature. Increased phenanthrene efflux was measured in cLP6a cells grown at 10°C and decreased efflux was observed at 35°C compared with cells grown at the optimum temperature of 28°C. Membrane fatty acids in cLP6a cells were substantially altered by changes in growth temperature and in the presence of tetracycline. Changed membrane fatty acids and increased membrane permeability were associated with ~30-fold increased expression of emhABC in cLP6a cells grown at 35°C, and with increased extracellular free fatty acids. Growth of P. fluorescens cLP6a at supra-optimal temperature was enhanced by the presence of EmhABC compared to strain cLP6a-1. Conclusions Combined, these observations suggest that the EmhABC efflux pump may be involved in the management of membrane stress effects such as those due to unfavourable incubation temperatures. Efflux of fatty acids replaced as a result of membrane damage or phospholipid turnover may be the primary physiological role of the EmhABC efflux pump in P. fluorescens cLP6a.

  5. Environmental pollution by antibiotics and by antibiotic resistance determinants

    International Nuclear Information System (INIS)

    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.

  6. 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 ...

  7. Introducing Aztreonam The First Monobactam Antibiotic, A Suitable Substitution for the Aminoglycosides

    Directory of Open Access Journals (Sweden)

    A. Jahanshahi M.Khajeh - Karamadeni S. Fazli Bazaz

    1992-07-01

    Full Text Available Aztreonam (Azactam for injection, squibb is the first member of a new and unique class of beta - lactam antibiotics designated by researchers at the Squibb Institute for Medical Research as monobactams (monocyclic bacterially produced beta - lactam antibiotics."nIn this research, for the first time, antimicrobial spectrum of aztrenoam was determined by Disk - Agar Diffusion (250 spp. and Macrodilution Broth Methods (150 Spp."nWe also compared this antibiotic with two routine aminoglycoside antibiotics (Amikacin, Gentamicin in Iran. The most active antibiotic in our study was aztreonam which had MIC50 & MIC90 of 4 & 32 ^g/ml specifically against Pseudomonas aeruginosa."nThis rate for the other aerobic gram - negative bacteria (E. coli, Kleb. pneumoniae, Proteus mirabilis, enterobacter spp., Shigella Spp. and Salmonella Spp. was less than 0.5 & 4 g/ml respectively."nAztreonam's MIC90 for kleb pneumoniae was 8/jg/mI our results were Correlated to the other studies"nAll aerobic gram - negative bacteria has been obtained from the Qhaem's Medical Center in Mashhad - IRAN."nThe results of Disk - Agar Diffusion Method determines that all bacteria were 100% susceptible against aztreonam except Pseudomonas aeruginosa with 83% susceptibility.

  8. Antimicrobial Susceptibility Pattern of Pseudomonas aeruginosa Isolated from Patients Referring to Hospitals

    Directory of Open Access Journals (Sweden)

    Zeynab Golshani

    2012-11-01

    Full Text Available Please cite this article as: Golshani Z, Ahadi AM, Sharifzadeh A. Antimicrobial Susceptibility Pattern of Pseudomonas aeruginosa Isolated from Patients Referring to Hospitals. Arch Hyg Sci 2012;1(2:48-53. Abstract: Background & Aims of the Study: The aim of this study was to detect and survey the antibiotic resistance pattern of Pseudomonas (P. aeruginosa isolated from patients in Isfahan (located in central Iran hospitals. Materials & Methods : A Total of 50 clinical isolates of P. aeruginosa were collected from urine, wound, trachea, ear swab, and pus, and then were confirmed by standard tests. Antibiotic susceptibility was determined by the Kirby-Bauer disc diffusion method. Susceptibility data were compared by chi-square test using SPSS version 15. Results: Among the isolated strains, resistance to oxacillin was seen in 100%, ceftriaxone in 76%, amikacin in 70%, ceftazidime in 68%, cefepime in 68%, tobramycin in 62%, gentamicin in 60%, ciprofloxacin in 58%, and imipenem in 58% of the isolates. Conclusions: Comparison of the results showed that, patterns of antibiotic resistance are different from one hospital to another in various areas. Therefore, it is suggested that such studies should be performed in different hospitals. Also, prescribing correct medications is essential to prevent further increases in resistant bacteria. References: 1. Pagani L, Mantengoli E, Migliavacca R, Nucleo E, Pollini S, Spalla M, et al. Multifocal Detection of Multidrug-Resistant Pseudomonas aeruginosa Producing the PER-1 Extended- Spectrum β-Lactamase in Northern Italy. J Clin Microbiol 2004;42(6:2523–9. 2. Ling TKW, Xiong J, Yu Y, Lee CC, Ye H, Hawkey PM, et al. Multicenter Antimicrobial Susceptibility Survey of Gram-Negative Bacteria Isolated from Patients with Community-Acquired Infections in the People's Republic of China. Antimicrob Agents Chemother 2006;50(1:374–8. 3. Gupta V, Datta P, Agnihotri N, Chander J. Comparative in vitro Activities of Seven

  9. 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.

  10. Bacterial Adhesion Forces with Substratum Surfaces and the Susceptibility of Biofilms to Antibiotics

    OpenAIRE

    Muszanska, Agnieszka K.; Nejadnik, M. Reza; Chen, Yun; van den Heuvel, Edwin R; Busscher, Henk J.; van der Mei, Henny C; Norde, Willem

    2012-01-01

    Biofilms causing biomaterial-associated infection resist antibiotic treatment and usually necessitate the replacement of infected implants. Here we relate bacterial adhesion forces and the antibiotic susceptibility of biofilms on uncoated and polymer brush-coated silicone rubber. Nine strains of Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa adhered more weakly to brush-coated silicone rubber (−0.05 ± 0.03 to −0.51 ± 0.62 nN) than to uncoated silicone rubber (−1...

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

    Science.gov (United States)

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

    2016-01-01

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

  12. PA3297 Counteracts Antimicrobial Effects of Azithromycin in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Hao eTan

    2016-03-01

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

  13. 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.

  14. The global problem of antibiotic resistance.

    Science.gov (United States)

    Gootz, Thomas D

    2010-01-01

    Amid the recent attention justly focused on the potential problem of microbial sources for weapons of bioterrorism, it is also apparent that human pathogens frequently isolated from infections in patients from community and hospital sources have been growing more resistant to commonly used antibiotics. Much of the growth of multiple-drug-resistant (MDR) bacterial pathogens can be contributed to the overuse of broad-spectrum antimicrobial products. However, an equally troubling and often overlooked component of the problem involves the elegant ways in which pathogenic bacteria continually evolve complex genetic systems for acquiring and regulating an endless array of antibiotic-resistance mechanisms. Efforts to develop new antimicrobials have over the past two decades been woefully behind the rapid evolution of resistance genes developing among both gram-positive and gram-negative pathogens. Several new agents that are best suited for use in the hospital environment have been developed to combat staphylococci resistant to beta-lactam antimicrobials following acquisition of the mecA gene. However, the dramatic spread in the US of the now common community strain of Staphylococcus aureus USA300 has shifted the therapeutic need for new antibiotics useful against MRSA to the community. As the pharmaceutical industry focused on discovering new agents for use against MRSA, hospitals in many parts of the world have seen the emergence of gram-negative pathogens such as Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae that are clinically resistant to almost all available antimicrobials. Such MDR isolates usually contain multiple-resistance determinants, including loss of outer membrane porins via gene inactivation by chromosomally encoded insertion sequences, up-regulation of inate efflux pumps, as well as acquisition of drug-inactivating enzymes whose genes are encoded on self-transmissible plasmids, integrons, and complex transposable elements

  15. 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...

  16. ANTIBIOTIC RESISTANCE AND CHROMIUM REDUCTION PATTERN AMONG ACTINOMYCETES

    Directory of Open Access Journals (Sweden)

    Preeti Jain

    2012-01-01

    Full Text Available Actinomycetes, one of the most important groups of microbes, exhibit many interesting activities such as degradation and transformation of organic and metal substrates together with production of antibiotics. With these bioactivities, actinomycetes would play an important role in the webs of the marine environment. The present study was designed to evaluate the antibiotic resistance pattern, antibiotic producing potential and chromium resistance as well as chromium reduction potential of a range of actinomycetes isolated from marine environments. Actinomycetes were isolated from marine sediment samples obtained from St. Martin’s Island in Bangladesh. Antibiotic resistance among the selected isolates was studied against 10 different antibiotics by disc diffusion method and antibiotic producing potential was assessed by the perpendicular streak method. The isolates were screened for resistance towards heavy metal Cr(VI on culture plates supplemented with Cr(VI at concentrations ranging from 1-5 mM of Cr(VI. Highly resistant isolates were subjected to screening for Cr(VI reduction activity, which was estimated using the Cr(VI specific colorimetric reagent 1, 5-diphenylcarbazide. Out of the total 30 different selected isolates, 25 (83.33% showed resistance against more than three antibiotics and 6 (20% showed resistance to more than six antibiotics. Ninety three percent of the isolates showed MAR index greater than 0.2 and tolerance to Cr(VI at 1mM of initial Cr(VI. None of the isolates displayed antimicrobial activity against the organisms tested. Among the isolates tested for chromate reduction, two were most efficient showing complete reduction of 1mM Cr(VI within 24 h. These two isolates (SM-11, SM-20 were capable of reducing chromate even at high initial Cr(VI concentrations. Remarkably, the isolate SM-11 was found to reduce 82.67%, 44.34% of Cr(VI at 2.5mM, 5mM of initial Cr(VI concentrations respectively, within 72h of incubation. The

  17. Pneumococcal resistance to antibiotics.

    OpenAIRE

    Klugman, K P

    1990-01-01

    The geographic distribution of pneumococci resistant to one or more of the antibiotics penicillin, erythromycin, trimethoprim-sulfamethoxazole, and tetracycline appears to be expanding, and there exist foci of resistance to chloramphenicol and rifampin. Multiply resistant pneumococci are being encountered more commonly and are more often community acquired. Factors associated with infection caused by resistant pneumococci include young age, duration of hospitalization, infection with a pneumo...

  18. Antibiotics in dental practice

    OpenAIRE

    2007-01-01

    The oral cavity and it surrounding tissue are habitats for many bacteria. Therefore a rationale for the use of antibacterial agents rises. During my time as a dental student, me often meet conditions were antibiotics are pointed out as the treatment of chose, as indicated or not recommended. According to Norwegian drug regulations (Tørisen 2007) dentists have: The right to requisition necessary medical agents in connection with dental treatment and prevention and treatment of diseases in the...

  19. 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 (A-NO2−, 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 A-NO2−. 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 A-NO2−, but also the membrane perturbing agent, EDTA and the antibiotics doxycycline, tigecycline, colistin, and chloramphenicol, respectively. Treatment of bacteria with A-NO2− plus EDTA, however, had the most dramatic and synergistic effect, with virtually all bacteria killed by 10 mM A-NO2−, and EDTA (1 mM, aerobic, anaerobic). Most importantly, the PA4455 mutant was also sensitive to A-NO2− in biofilms. A-NO2− 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, A-NO2− as well as EDTA. Furthermore, the synergy between the two compounds could offer future benefits against antibiotic resistant PA strains. PMID:27064218

  20. The Pseudomonas Quinolone Signal (PQS)

    DEFF Research Database (Denmark)

    Sams, Thomas; Baker, Ysobel; Hodgkinson, James;

    2015-01-01

    is now known to be under the con-trol of the quorum sensing (QS) system. Over the last15 years, the Pseudomonas quinolone signal (PQS) has beenfound to play a crucial role in QS by linking the two seg-ments (las and rhl) of the P. aeruginosa N-acylhomoserinelactone-dependent QS signaling pathways...

  1. 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

    2016-01-01

    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. PMID:27151804

  2. Structure Revision of N-Mercapto-4-formylcarbostyril Produced by Pseudomonas fluorescens G308 to 2-(2-Hydroxyphenyl)thiazole-4-carbaldehyde [aeruginaldehyde

    DEFF Research Database (Denmark)

    Guillemyn, Karel; Ballet, Steven; Ye, Lumeng;

    2014-01-01

    An antibiotic substance isolated from Pseudomonas fluorescens strain G308 was earlier assigned the structure of N-mercapto-4-formylcarbostyril, but computational predictions of the H-1 and C-13 NMR magnetic shielding tensors show this structure to be incompatible with the published spectroscopic ...

  3. Optimizing Antibiotic Use in Nursing Homes Through Antibiotic Stewardship.

    Science.gov (United States)

    Sloane, Philip D; Huslage, Kirk; Kistler, Christine E; Zimmerman, Sheryl

    2016-01-01

    Antibiotic stewardship is becoming a requirement for nursing homes. Programs should be interdisciplinary and multifaceted; should have support from nursing home administrators; and should aim to promote antibiotics only when needed, not just in case. Recommended components include use of evidence-based guidelines; ongoing monitoring of antibiotic prescriptions, cultures, and study results; monitoring of health outcomes; use of nursing home-specific antibiograms; regular reporting and feedback to medical providers and nurses; and education of residents and families. PMID:27621341

  4. A STUDY OF METALLO-BETA-LACTATAMASE PRODUCING PSEUDOMONAS AERUGINOSA IN CLINICAL SAMPLES OF S.S.G. HOSPITAL

    Directory of Open Access Journals (Sweden)

    Mehul S Chaudhari Tanuja B Javadekar Govind Ninama Neelam Pandya Jivraj Damor

    2011-04-01

    Full Text Available Introduction: Pseudomonas spp. is common pathogen causing nosocomial infection. Acquired drug resistance is frequent in nosocomial isolates of Pseudomonas spp. Acquired metallo-β-lactamases (MBL in pseudomonas spp. have recently emerged as one of the most worrisome resistance mechanism because of their capacity to hydrolyze all beta-lactam antibiotics including penicillins, cephalosporins and carbapenems, with the exception of aztreonam. Aim: To detect metallo-β-lactamase producing isolates of Pseudomonas aerugenosa from various clinical samples from patients admitted in our hospital. Material and methods : In this studyt we studied the prevalence, following standard methods of isolation and identification techniques of these bacteria from clinical materials Source : Samples of patients from different wards of S.S.G.Hosital are proceeded in Microbiology department , Medical College and S.S.G.Hospital Baroda. Results: Of total study of 150 isolates of Pseudomonas aeruginosa, 8 isolates are resistance to Imipenem . Of 8 samples , all are producing Metallo-Beta-Lactamase enzyme. Conclusion :Infection cause by MBL (metallo-β-lactamase positive isolates of Pseudomonas aerugenosa is important to identify because it poses not only therapeutic problem, but also a serious concern for infection control management. [National J of Med Res 2011; 1(2.000: 60-63

  5. 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.

  6. 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...

  7. Co-selection of antibiotic and metal(loid) resistance in gram-negative epiphytic bacteria from contaminated salt marshes.

    Science.gov (United States)

    Henriques, Isabel; Tacão, Marta; Leite, Laura; Fidalgo, Cátia; Araújo, Susana; Oliveira, Cláudia; Alves, Artur

    2016-08-15

    The goal of this study was to investigate co-selection of antibiotic resistance in gram-negative epiphytic bacteria. Halimione portulacoides samples were collected from metal(loid)-contaminated and non-contaminated salt marshes. Bacterial isolates (n=137) affiliated with Vibrio, Pseudomonas, Shewanella, Comamonas, Aeromonas and with Enterobacteriaceae. Vibrio isolates were more frequent in control site while Pseudomonas was common in contaminated sites. Metal(loid) and antibiotic resistance phenotypes varied significantly according to site contamination, and multiresistance was more frequent in contaminated sites. However, differences among sites were not observed in terms of prevalence or diversity of acquired antibiotic resistance genes, integrons and plasmids. Gene merA, encoding mercury resistance, was only detected in isolates from contaminated sites, most of which were multiresistant to antibiotics. Results indicate that metal(loid) contamination selects for antibiotic resistance in plant surfaces. In salt marshes, antibiotic resistance may be subsequently transferred to other environmental compartments, such as estuarine water or animals, with potential human health risks. PMID:27210560

  8. Antibiotic prevention of postcataract endophthalmitis

    DEFF Research Database (Denmark)

    Kessel, Line; Flesner, Per; Andresen, Jens;

    2015-01-01

    Endophthalmitis is one of the most feared complications after cataract surgery. The aim of this systematic review was to evaluate the effect of intracameral and topical antibiotics on the prevention of endophthalmitis after cataract surgery. A systematic literature review in the MEDLINE, CINAHL......, Cochrane Library and EMBASE databases revealed one randomized trial and 17 observational studies concerning the prophylactic effect of intracameral antibiotic administration on the rate of endophthalmitis after cataract surgery. The effect of topical antibiotics on endophthalmitis rate was reported by one...... with the use of intracameral antibiotic administration of cefazolin, cefuroxime and moxifloxacin, whereas no effect was found with the use of topical antibiotics or intracameral vancomycin. Endophthalmitis occurred on average in one of 2855 surgeries when intracameral antibiotics were used compared to...

  9. Pseudomonas chlororaphis Strain Sm3, Bacterial Antagonist of Pratylenchus penetrans.

    Science.gov (United States)

    Hackenberg, C; Muehlkchen, A; Forge, T; Vrain, T

    2000-06-01

    The interaction of Pseudomonas chlororaphis strain Sm3 and the root-lesion nematode Pratylenchus penetrans was investigated in three separate greenhouse experiments with soils from southern British Columbia, Canada. The bacteria were applied to the roots of strawberry plants and planted in unpasteurized field soils, with natural or supplemented infestation of P. penetrans. Nematode suppression in roots was evident after 6 or 10 weeks in all experiments. Root or shoot growth were increased after 10 weeks in two experiments. Population dynamics of P. chlororaphis Sm3 in the rhizosphere was followed using an antibiotic-resistant mutant of P. chlororaphis Sm3. There was no apparent correlation between bacterial density in the rhizosphere and P. penetrans suppression in strawberry roots and rhizosphere soil, although the soil with the highest nematode reduction also had the largest P. chlororaphis Sm3 population in the rhizosphere. PMID:19270964

  10. Attenuation of Pseudomonas aeruginosa virulence by quorum sensing inhibitors

    DEFF Research Database (Denmark)

    Hentzer, Morten; Wu, H.; Andersen, Jens Bo;

    2003-01-01

    afforded a novel opportunity to control infectious bacteria without interfering with growth. Compounds that can override communication signals have been found in the marine environment. Using Pseudomonas aeruginosa PAO1 as an example of an opportunistic human pathogen, we show that a synthetic derivate of...... systems and inhibited virulence factor expression. Application of the drug to P.aeruginosa biofilms increased bacterial susceptibility to tobramycin and SDS. In a mouse pulmonary infection model, the drug inhibited quorum sensing of the infecting bacteria and promoted their clearance by the mouse immune......Traditional treatment of infectious diseases is based on compounds that kill or inhibit growth of bacteria. A major concern with this approach is the frequent development of resistance to antibiotics. The discovery of communication systems (quorum sensing systems) regulating bacterial virulence has...

  11. Antibiotics in otorhinolaryngology practice

    Directory of Open Access Journals (Sweden)

    Stefan-Mikić Sandra

    2002-01-01

    Full Text Available Introduction This study investigated utilization of antibacterial agents at the Ear, Nose and Throat Department of the Outpatient Service of the Health Center Novi Sad - Liman and at the Ear, Nose and Throat Clinic of the Clinical Center Novi Sad, in the period February - March 2001. Material and methods All antibacterial agents were classified as group J, regarding Anatomic-Therapeutic-Chemical Classification. Data on drug utilization were presented in Defined Daily Doses (DDD. Patients who were under observation were all treated with antibiotics. Results In regard to prescribed treatment in the Ear, Nose and Throat Department of the Outpatient Service of the Health Center Novi Sad - Liman, most outpatients were treated with macrolide antibiotics - in 26.21%; combination of penicillin and beta-lactamase inhibitors in 20.83% and pyranosides in 16.12%. At the Ear, Nose and Throat Clinic of the Clinical Center Novi Sad, macrolides and lincosamines were most frequently used - in 20.46%; cephalosporins in 19.87% and penicillins susceptible to beta-lactamase in 18.85%. It is extremely positive and in agreement with current pharmacotherapeutic principles that in both institutions peroral ampicillins have not been prescribed. Aminoglycosides have been prescribed in less than 1% of patients of the Ear, Nose and Throat Department of the Outpatient Service of the Health Center Novi Sad - Liman, whereas they were much more frequently prescribed at the Ear, Nose and Throat Clinic of the Clinical Center Novi Sad - in 11.25%. Although there is a positive postantibiotic effect in regard to these antibiotics and it is recommended to use them once a day, in both examined institutions aminoglycosides were given twice a day. In regard to bacterial identification it was done in 80.76% of patients of the Ear, Nose and Throat Department of the Outpatient Service of the Health Center Novi Sad - Liman, while in the Ear, Nose and Throat Clinic of the Clinical Center

  12. Salt tolerance of bacteria isolated from tropical marine fish and prawn

    OpenAIRE

    P.K. Surendran; Mahadeva Iyer, K.; Gopakumar, K

    1983-01-01

    Salt tolerance of selected cultures of Pseudomonas, Moraxella, Vibrio, Micrococcus, Acinetobacter and Flavobacteria/ Cytophaga was determined. More than 80% of the cultures belonging to each of the above genera, were capable of growth in presence of 1.5 to 3.5% salt (NaCl) and at least 25 to 30% of the cultures in each group required 1.5 to 3.5% salt for growth. 40% each of Pseudomonas and Vibrio strains and 30% each of Moraxella, Micrococcus and Flavobacteria/Cytophaga strains tolerated 10% ...

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

    Directory of Open Access Journals (Sweden)

    Yongming Sang

    2014-12-01

    Full Text Available 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 ecological and immunological interactions. Most previous reviews of antibiotic resistance focus on resisters but overlook persisters, although both are fundamental to bacteria survival through antibiosis. Here, we discuss resisters and persisters together to contrast the distinct ecological responses of persisters during antibiotic stress and propose different regimens to eradicate persisters. Our intention is not only to provide an ecoimmunological interpretation, but also to use an ecoimmunological system to categorize available alternatives and promote the discovery of prospective approaches to relieve ART problems within the general scope of improving animal health. Thus, we will categorize available alternatives to antibiotics and envision applications of ecoimmunological tenets to promote related studies in animal production.

  14. Alternatives to antibiotics in animal agriculture: an ecoimmunological view.

    Science.gov (United States)

    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 ecological and immunological interactions. Most previous reviews of antibiotic resistance focus on resisters but overlook persisters, although both are fundamental to bacteria survival through antibiosis. Here, we discuss resisters and persisters together to contrast the distinct ecological responses of persisters during antibiotic stress and propose different regimens to eradicate persisters. Our intention is not only to provide an ecoimmunological interpretation, but also to use an ecoimmunological system to categorize available alternatives and promote the discovery of prospective approaches to relieve ART problems within the general scope of improving animal health. Thus, we will categorize available alternatives to antibiotics and envision applications of ecoimmunological tenets to promote related studies in animal production. PMID:25551290

  15. Antibiotics and oral contraceptives.

    Science.gov (United States)

    Rubin, D F

    1981-04-01

    Dermatologists often prescribe oral tetracycline for the control of acne, primarily, and to a much lesser extent, for the treatment of cutaneous infections. A number of the patients taking tetracycline are also taking birth control pills. A recent article in the British Medical Journal (1980;1:293) indicates that this combination can lead to a failure of the (OC) oral contraceptive. Such failure had been associated with ampicillin as well. It is believed that the mechanism for this was the disturbance in normal gut flora, with consequent effects on bacterial hydrolysis of steroid conjugates. This would interrupt the enterohepatic circulation of contraceptive steroids, resulting in a less than normal concentration of circulating steroids. It was recommended that women taking low-dose OCs take extra precautions against pregnancy during any cycle in which antibiotics are given. In regard to our care of and responsibilities to our patients, and in an era when malpractice suits for all types of reasons are more common, it certainly behooves dermatologists to recognize and be concerned about this potential consequence of prescribing oral antibiotics. PMID:7212735

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

    Science.gov (United States)

    Freschi, Luca; Jeukens, Julie; Kukavica-Ibrulj, Irena; Boyle, Brian; Dupont, Marie-Josée; Laroche, Jérôme; Larose, Stéphane; Maaroufi, Halim; Fothergill, Joanne L; Moore, Matthew; Winsor, Geoffrey L; Aaron, Shawn D; Barbeau, Jean; Bell, Scott C; Burns, Jane L; Camara, Miguel; Cantin, André; Charette, Steve J; Dewar, Ken; Déziel, Éric; Grimwood, Keith; Hancock, Robert E W; Harrison, Joe J; Heeb, Stephan; Jelsbak, Lars; Jia, Baofeng; Kenna, Dervla T; Kidd, Timothy J; Klockgether, Jens; Lam, Joseph S; Lamont, Iain L; Lewenza, Shawn; Loman, Nick; Malouin, François; Manos, Jim; McArthur, Andrew G; McKeown, Josie; Milot, Julie; Naghra, Hardeep; Nguyen, Dao; Pereira, Sheldon K; Perron, Gabriel G; Pirnay, Jean-Paul; Rainey, Paul B; Rousseau, Simon; Santos, Pedro M; Stephenson, Anne; Taylor, Véronique; Turton, Jane F; Waglechner, Nicholas; Williams, Paul; Thrane, Sandra W; Wright, Gerard D; Brinkman, Fiona S L; Tucker, Nicholas P; Tümmler, Burkhard; Winstanley, Craig; Levesque, Roger C

    2015-01-01

    The International Pseudomonas aeruginosa Consortium is sequencing over 1000 genomes and building an analysis pipeline for the study of Pseudomonas genome evolution, antibiotic resistance and virulence genes. Metadata, including genomic and phenotypic data for each isolate of the collection, are available through the International Pseudomonas Consortium Database (http://ipcd.ibis.ulaval.ca/). Here, we present our strategy and the results that emerged from the analysis of the first 389 genomes. With as yet unmatched resolution, our results confirm that P. aeruginosa strains can be divided into three major groups that are further divided into subgroups, some not previously reported in the literature. We also provide the first snapshot of P. aeruginosa strain diversity with respect to antibiotic resistance. Our approach will allow us to draw potential links between environmental strains and those implicated in human and animal infections, understand how patients become infected and how the infection evolves over time as well as identify prognostic markers for better evidence-based decisions on patient care. PMID:26483767

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

    Directory of Open Access Journals (Sweden)

    Luca eFreschi

    2015-09-01

    Full Text Available The International Pseudomonas aeruginosa Consortium is sequencing over 1000 genomes and building an analysis pipeline for the study of Pseudomonas genome evolution, antibiotic resistance and virulence genes. Metadata, including genomic and phenotypic data for each isolate of the collection, are available through the International Pseudomonas Consortium Database (http://ipcd.ibis.ulaval.ca/. Here, we present our strategy and the results that emerged from the analysis of the first 389 genomes. With as yet unmatched resolution, our results confirm that P. aeruginosa strains can be divided into three major groups that are further divided into subgroups, some not previously reported in the literature. We also provide the first snapshot of P. aeruginosa strain diversity with respect to antibiotic resistance. Our approach will allow us to draw potential links between environmental strains and those implicated in human and animal infections, understand how patients become infected and how the infection evolves over time as well as identify prognostic markers for better evidence-based decisions on patient care.

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

    International Nuclear Information System (INIS)

    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)

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

    Science.gov (United States)

    Freschi, Luca; Jeukens, Julie; Kukavica-Ibrulj, Irena; Boyle, Brian; Dupont, Marie-Josée; Laroche, Jérôme; Larose, Stéphane; Maaroufi, Halim; Fothergill, Joanne L.; Moore, Matthew; Winsor, Geoffrey L.; Aaron, Shawn D.; Barbeau, Jean; Bell, Scott C.; Burns, Jane L.; Camara, Miguel; Cantin, André; Charette, Steve J.; Dewar, Ken; Déziel, Éric; Grimwood, Keith; Hancock, Robert E. W.; Harrison, Joe J.; Heeb, Stephan; Jelsbak, Lars; Jia, Baofeng; Kenna, Dervla T.; Kidd, Timothy J.; Klockgether, Jens; Lam, Joseph S.; Lamont, Iain L.; Lewenza, Shawn; Loman, Nick; Malouin, François; Manos, Jim; McArthur, Andrew G.; McKeown, Josie; Milot, Julie; Naghra, Hardeep; Nguyen, Dao; Pereira, Sheldon K.; Perron, Gabriel G.; Pirnay, Jean-Paul; Rainey, Paul B.; Rousseau, Simon; Santos, Pedro M.; Stephenson, Anne; Taylor, Véronique; Turton, Jane F.; Waglechner, Nicholas; Williams, Paul; Thrane, Sandra W.; Wright, Gerard D.; Brinkman, Fiona S. L.; Tucker, Nicholas P.; Tümmler, Burkhard; Winstanley, Craig; Levesque, Roger C.

    2015-01-01

    The International Pseudomonas aeruginosa Consortium is sequencing over 1000 genomes and building an analysis pipeline for the study of Pseudomonas genome evolution, antibiotic resistance and virulence genes. Metadata, including genomic and phenotypic data for each isolate of the collection, are available through the International Pseudomonas Consortium Database (http://ipcd.ibis.ulaval.ca/). Here, we present our strategy and the results that emerged from the analysis of the first 389 genomes. With as yet unmatched resolution, our results confirm that P. aeruginosa strains can be divided into three major groups that are further divided into subgroups, some not previously reported in the literature. We also provide the first snapshot of P. aeruginosa strain diversity with respect to antibiotic resistance. Our approach will allow us to draw potential links between environmental strains and those implicated in human and animal infections, understand how patients become infected and how the infection evolves over time as well as identify prognostic markers for better evidence-based decisions on patient care. PMID:26483767

  20. Antibiotic-free selection in E. coli: new considerations for optimal design and improved production

    Directory of Open Access Journals (Sweden)

    Peubez Isabelle

    2010-09-01

    Full Text Available Abstract Background The increasing regulatory requirements to which biological agents are subjected will have a great impact in the field of industrial protein expression and production. There is an expectation that in a near future, there may be "zero tolerance" towards antibiotic-based selection and production systems. Besides the antibiotic itself, the antibiotic resistance gene is an important consideration. The complete absence of antibiotic-resistance gene being the only way to ensure that there is no propagation in the environment or transfer of resistance to pathogenic strains. Results In a first step, we have designed a series of vectors, containing a stabilization element allowing a complete elimination of antibiotics during fermentation. Vectors were further improved in order to include alternative selection means such as the well known poison/antidote stabilization system. Eventually we propose an elegant positive pressure of selection ensuring the elimination of the antibiotic-resistance gene through homologous recombination. In addition, we have shown that the presence of an antibiotic resistance gene can indirectly reduce the amount of expressed protein, since even in absence of selection pressure the gene would be transcribed and account for an additional stress for the host during the fermentation process. Conclusions We propose a general strategy combining plasmid stabilization and antibiotic-free selection. The proposed host/vector system, completely devoid of antibiotic resistance gene at the end of construction, has the additional advantage of improving recombinant protein expression and/or plasmid recovery.

  1. CHEMICALLY FABRICATED SILVER NANOPARTICLES ENHANCES THE ACTIVITY OF ANTIBIOTICS AGAINST SELECTED HUMAN BACTERIAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    S. Thangapandiyan and P. Prema*

    2012-05-01

    Full Text Available Due to the outbreak of infectious diseases caused by different pathogenic bacteria and the development of antibiotic resistance, the pharmaceutical companies and the researchers are now searching for new unconventional antibacterial agents. Nanotechnology represents a modern and innovative approach to develop new formulations based on metallic nanoparticles with antimicrobial properties. The potential bioactivity of chemically fabricated silver nanoparticles has been extensively studied. However, the antibacterial activity of silver nanoparticles individually or in combination with different antibiotics has not been demonstrated. In the present investigations, the effect of silver nanoparticles on the antibacterial activity of different antibiotics was evaluated against selected human bacterial pathogens such as Staphylococcus aureus, Streptococcus epidermis, Escherichia coli, Pseudomonas aeruginosa, and Bacillus cereus by disc diffusion method. In the presence of sub - inhibitory concentration of silver nanoparticles (100µL/disc, the antibacterial activities of all antibiotics are increased from 1 mm to 10 mm. The maximum fold increase was noticed for vancomycin against Pseudomonas aeruginosa (66.67%, Escherichia coli (62.50%, and Staphylococcus aureus (46% followed by rifampicin against Bacillus cereus (66.67% and kanamycin against Streptococcus epidermis (25%. These results signify that the silver nanoparticles showed potential antibacterial action of ß-lactams, glycopeptides, aminoglycosides, sulphonamides suggesting a possible utilization of silver nanocompounds in combination therapy against selected pathogens used in the experiment.

  2. Multiple Pathways of Genome Plasticity Leading to Development of Antibiotic Resistance

    Directory of Open Access Journals (Sweden)

    Didier Mazel

    2013-05-01

    Full Text Available The emergence of multi-resistant bacterial strains is a major source of concern and has been correlated with the widespread use of antibiotics. The origins of resistance are intensively studied and many mechanisms involved in resistance have been identified, such as exogenous gene acquisition by horizontal gene transfer (HGT, mutations in the targeted functions, and more recently, antibiotic tolerance through persistence. In this review, we focus on factors leading to integron rearrangements and gene capture facilitating antibiotic resistance acquisition, maintenance and spread. The role of stress responses, such as the SOS response, is discussed.

  3. Antibiotic Bactericidal Activity Is Countered by Maintaining pH Homeostasis in Mycobacterium smegmatis.

    Science.gov (United States)

    Bartek, I L; Reichlen, M J; Honaker, R W; Leistikow, R L; Clambey, E T; Scobey, M S; Hinds, A B; Born, S E; Covey, C R; Schurr, M J; Lenaerts, A J; Voskuil, M I

    2016-01-01

    Antibiotics target specific biosynthetic processes essential for bacterial growth. It is intriguing that several commonalities connect the bactericidal activity of seemingly disparate antibiotics, such as the numerous conditions that confer broad-spectrum antibiotic tolerance. Whether antibiotics kill in a manner unique to their specific targets or by a universal mechanism is a critical and contested subject. Herein, we demonstrate that the bactericidal activity of diverse antibiotics against Mycobacterium smegmatis and four evolutionarily divergent bacterial pathogens was blocked by conditions that worked to maintain intracellular pH homeostasis. Single-cell pH analysis demonstrated that antibiotics increased the cytosolic pH of M. smegmatis, while conditions that promoted proton entry into the cytosol prevented intracellular alkalization and antibiotic killing. These findings led to a hypothesis that posits antibiotic lethality occurs when antibiotics obstruct ATP-consuming biosynthetic processes while metabolically driven proton efflux is sustained despite the loss of proton influx via ATP synthase. Consequently, without a concomitant reduction in respiratory proton efflux, cell death occurs due to intracellular alkalization. Our findings indicate the effects of antibiotics on pH homeostasis should be considered a potential mechanism contributing to antibiotic lethality. IMPORTANCE Since the discovery of antibiotics, mortality due to bacterial infection has decreased dramatically. However, infections from difficult to treat bacteria such as Mycobacterium tuberculosis and multidrug-resistant pathogens have been on the rise. An understanding of the cascade of events that leads to cell death downstream of specific drug-target interactions is not well understood. We have discovered that killing by several classes of antibiotics was stopped by maintaining pH balance within the bacterial cell, consistent with a shared mechanism of antibiotic killing. Our findings

  4. The effect of phylogenetically different bacteria on the fitness of Pseudomonas fluorescens in sand microcosms.

    Directory of Open Access Journals (Sweden)

    Olaf Tyc

    Full Text Available In most environments many microorganisms live in close vicinity and can interact in various ways. Recent studies suggest that bacteria are able to sense and respond to the presence of neighbouring bacteria in the environment and alter their response accordingly. This ability might be an important strategy in complex habitats such as soils, with great implications for shaping the microbial community structure. Here, we used a sand microcosm approach to investigate how Pseudomonas fluorescens Pf0-1 responds to the presence of monocultures or mixtures of two phylogenetically different bacteria, a Gram-negative (Pedobacter sp. V48 and a Gram-positive (Bacillus sp. V102 under two nutrient conditions. Results revealed that under both nutrient poor and nutrient rich conditions confrontation with the Gram-positive Bacillus sp. V102 strain led to significant lower cell numbers of Pseudomonas fluorescens Pf0-1, whereas confrontation with the Gram-negative Pedobacter sp. V48 strain did not affect the growth of Pseudomonas fluorescens Pf0-1. However, when Pseudomonas fluorescens Pf0-1 was confronted with the mixture of both strains, no significant effect on the growth of Pseudomonas fluorescens Pf0-1 was observed. Quantitative real-time PCR data showed up-regulation of genes involved in the production of a broad-spectrum antibiotic in Pseudomonas fluorescens Pf0-1 when confronted with Pedobacter sp. V48, but not in the presence of Bacillus sp. V102. The results provide evidence that the performance of bacteria in soil depends strongly on the identity of neighbouring bacteria and that inter-specific interactions are an important factor in determining microbial community structure.

  5. An outbreak of forty five cases of Pseudomonas aeruginosa acute endophthalmitis after phacoemulsification Surto de quarenta e cinco casos de endoftalmite aguda por Pseudomonas aeruginosa após facoemulsificação

    OpenAIRE

    Ricardo Luz Leitão Guerra; Bruno de Paula Freitas; Cintia Maria Felix Medrado Parcero; Otacílio de Oliveira Maia Júnior; Roberto Lorens Marback

    2012-01-01

    PURPOSE: To describe an outbreak of Pseudomonas aeruginosa endophthalmitis post cataract surgery. Clinical findings, treatment and outcome are discussed. METHODS: Clinical charts review of forty-five patients treated for endophthalmitis in a two-day period. The patients underwent primary vitrectomy, anterior chamber irrigation and intravitreous antibiotic injection. Cultures from vitreous and anterior chamber samples were performed in all patients. RESULTS: Forty-five patients (twenty-three m...

  6. Elucidating pharmacodynamic interaction of silver nanoparticle - topical deliverable antibiotics

    Science.gov (United States)

    Thirumurugan, G.; Seshagiri Rao, J. V. L. N.; Dhanaraju, M. D.

    2016-07-01

    In order to exploit the potential benefits of antimicrobial combination therapy, we need a better understanding of the circumstances under which pharmacodynamic interactions expected. In this study, Pharmacodynamic interactions between silver nanoparticle (SNP) and topical antibiotics such as Cefazolin (CEF), Mupirocin (MUP), Gentamycin (GEN), Neomycin (NEO), Tetracycline (TET), Vancomycin (VAN) were investigated using the MIC test, Combination assay followed by Fractional Inhibitory concentration Index and Agar well diffusion method. SNP + MUP, SNP + NEO, SNP + VAN combinations showed Synergism (SN) and SNP + CEF, SNP + GEN, SNP + TET showed Partial synergism (PS) against Staphylococcus aureus. Four combinations (SNP + CEF, SNP + MUP, SNP + GEN, SNP + VAN) showed SN, SNP + TET showed PS and Indifferent effect (ID) were observed for SNP + NEO against Pseudomonas aeruginosa. SN was observed for SNP + CEF, SNP + GEN, SNP + NEO, SNP + TET and SNP + MUP showed ID, SNP + VAN showed PS against Escherichia coli. In addition, we elucidated the possible mechanism involved in the pharmacodynamic interaction between SNP-topical antibiotics by increased ROS level, membrane damage following protein release, K+ leakage and biofilm inhibition. Thus, our findings support that conjugation of the SNP with topical antibiotics have great potential in the topical formulation when treating complex resistant bacterial infections and where there is a need of more concentration to kill pathogenic bacteria.

  7. Structure, toxicity and antibiotic activity of gramicidin S and derivatives.

    Science.gov (United States)

    Swierstra, J; Kapoerchan, V; Knijnenburg, A; van Belkum, A; Overhand, M

    2016-05-01

    Development of new antibiotics is declining whereas antibiotic resistance is rising, heralding a post-antibiotic era. Antimicrobial peptides such as gramicidin S (GS), exclusively topically used due to its hemolytic side-effect, could still be interesting as therapeutic compounds. By modifying the amino-acid composition of GS, we synthesized GS analogues. We now show that derivative VK7 has a lower MIC (7.8-31.2 μg/ml, median 15.6 μg/ml) against strains of multi-drug resistant (MDR) Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa than GS has (3.9-62.5 μg/ml, median 31.3 μg/ml). Low MICs for both VK7 and GS were observed for Staphylococcus aureus and Enterococcus faecium. VK7 showed reduced haemolysis and less lactate dehydrogenase release. All compounds were fully bactericidal at MIC values. Modification of GS enables production of novel derivatives potentially useful for systemic treatment of human infections. PMID:26886453

  8. In Vitro Pharmacodynamics of Levofloxacin and Other Aerosolized Antibiotics under Multiple Conditions Relevant to Chronic Pulmonary Infection in Cystic Fibrosis ▿

    OpenAIRE

    King, Paula; Lomovskaya, Olga; Griffith, David C.; Burns, Jane L.; Dudley, Michael N.

    2009-01-01

    The inhalational administration of antibiotics can provide high concentrations locally in the lungs of cystic fibrosis patients and, thus, can be useful for the treatment of chronic bacterial infections. The present study evaluated the in vitro activities of levofloxacin, ciprofloxacin, tobramycin, amikacin, and aztreonam against clinical isolates of Pseudomonas aeruginosa, Burkholderia cepacia complex, Stenotrophomonas maltophilia, Alcaligenes xylosoxidans, and Staphylococcus aureus from cys...

  9. RHIZOBIUM ETLI USDA9032 ENGINEERED TO PRODUCE A PHENAZINE ANTIBIOTIC INHIBITS THE GROWTH OF FUNGAL PATHOGENS BUT IS IMPAIRED IN SYMBIOTIC PERFORMANCE

    Science.gov (United States)

    Phenazine antibiotics produced by Pseudomonas spp. play a major role in preventing various plant diseases. In this study, the phenazine biosynthesis locus of P. chlororaphis O6, a plant growth-promoting rhizobacteria (PGPR), was introduced into several symbiotic bacteria belonging to the family Rh...

  10. Phosphate taxis in Pseudomonas aeruginosa.

    OpenAIRE

    Kato, J.; Ito, A.; Nikata, T; Ohtake, H

    1992-01-01

    Pseudomonas aeruginosa was shown to be attracted to phosphate. The chemotactic response was induced by phosphate starvation. The specificity of chemoreceptors for phosphate was high so that no other tested phosphorus compounds elicited a chemotactic response as strong as that elicited by phosphate. Competition experiments showed that the chemoreceptors for phosphate appeared to be different from those for the common amino acids. Mutants constitutive for alkaline phosphatase showed the chemota...

  11. Chromium reduction in Pseudomonas putida.

    OpenAIRE

    Ishibashi, Y.; Cervantes, C; Silver, S

    1990-01-01

    Reduction of hexavalent chromium (chromate) to less-toxic trivalent chromium was studied by using cell suspensions and cell-free supernatant fluids from Pseudomonas putida PRS2000. Chromate reductase activity was associated with soluble protein and not with the membrane fraction. The crude enzyme activity was heat labile and showed a Km of 40 microM CrO4(2-). Neither sulfate nor nitrate affected chromate reduction either in vitro or with intact cells.

  12. Chromium reduction in Pseudomonas putida.

    Science.gov (United States)

    Ishibashi, Y; Cervantes, C; Silver, S

    1990-01-01

    Reduction of hexavalent chromium (chromate) to less-toxic trivalent chromium was studied by using cell suspensions and cell-free supernatant fluids from Pseudomonas putida PRS2000. Chromate reductase activity was associated with soluble protein and not with the membrane fraction. The crude enzyme activity was heat labile and showed a Km of 40 microM CrO4(2-). Neither sulfate nor nitrate affected chromate reduction either in vitro or with intact cells. PMID:2389940

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

    Science.gov (United States)

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

    2015-10-01

    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. PMID:26114900

  14. Isolation and characterization of antibiotic-resistant bacteria from pharmaceutical industrial wastewaters.

    Science.gov (United States)

    Tahrani, Leyla; Soufi, Leila; Mehri, Ines; Najjari, Afef; Hassan, Abdenaceur; Van Loco, Joris; Reyns, Tim; Cherif, Ameur; Ben Mansour, Hedi

    2015-12-01

    Contamination of surface waters in underdeveloped countries is a great concern. Treated and untreated wastewaters have been discharged into rivers and streams, leading to possible waterborne infection outbreaks which may represent a significant dissemination mechanism of antibiotic resistance genes among pathogenic bacterial populations. The present study aims to determine the multi-drug resistance patterns among isolated and identified bacterial strains in a pharmaceutical wastewater effluent in north Tunisia. Fourteen isolates were obtained and seven of them were identified. These isolates belong to different genera namely, Pseudomonas, Acinetobacter, Exiguobacterium, Delftia and Morganella. Susceptibility patterns of these isolates were studied toward commonly used antibiotics in Tunisia. All the identified isolates were found to have 100% susceptibility against colistin sulfate and 100% resistance against amoxicillin. Among the 11 antibiotics tested, six patterns of multi-drug resistance were obtained. The potential of the examined wastewater effluent in spreading multi-drug resistance and the associated public health implications are discussed. PMID:26343496

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    Cystic fibrosis (CF) patients have increased susceptibility to chronic lung infections by Pseudomonas aeruginosa, but the ecophysiology within the CF lung during infections is poorly understood. The aim of this study was to elucidate the in vivo growth physiology of P. aeruginosa within lungs of...... whereby PMNs slow the growth of the bacteria and render them less susceptible to antibiotic treatment while enabling them to persist by anaerobic respiration....

  16. Complete genome sequences of three Pseudomonas aeruginosa isolates with phenotypes of polymyxin B adaptation and inducible resistance.

    Science.gov (United States)

    Boyle, Brian; Fernandez, Lucia; Laroche, Jerome; Kukavica-Ibrulj, Irena; Mendes, Caio M F; Hancock, Robert W; Levesque, Roger C

    2012-01-01

    Clinical "superbug" isolates of Pseudomonas aeruginosa were previously observed to be resistant to several antibiotics, including polymyxin B, and/or to have a distinct, reproducible adaptive polymyxin resistance phenotype, identified by observing "skipped" wells (appearance of extra turbid wells) during broth microdilution testing. Here we report the complete assembled draft genome sequences of three such polymyxin resistant P. aeruginosa strains (9BR, 19BR, and 213BR). PMID:22207740

  17. Complete Genome Sequences of Three Pseudomonas aeruginosa Isolates with Phenotypes of Polymyxin B Adaptation and Inducible Resistance

    OpenAIRE

    Boyle, Brian; Fernandez, Lucia; Laroche, Jerome; Kukavica-Ibrulj, Irena; Caio M. F. Mendes; Hancock, Robert W.; Levesque, Roger C.

    2012-01-01

    Clinical “superbug” isolates of Pseudomonas aeruginosa were previously observed to be resistant to several antibiotics, including polymyxin B, and/or to have a distinct, reproducible adaptive polymyxin resistance phenotype, identified by observing “skipped” wells (appearance of extra turbid wells) during broth microdilution testing. Here we report the complete assembled draft genome sequences of three such polymyxin resistant P. aeruginosa strains (9BR, 19BR, and 213BR).

  18. Analysis of integrons and associated gene cassettes in clinical isolates of multidrug resistant Pseudomonas aeruginosa from Southwest Nigeria

    OpenAIRE

    Odumosu, Bamidele T; Adeniyi, Bolanle A.; Chandra, Ram

    2013-01-01

    Background Multidrug resistant Pseudomonas aeruginosa harbours integrons and other mobile genetic elements such as plasmids and transposons, which easily disseminate antibiotic resistance genes among clinical strains of P. aeruginosa. Methodology Plasmid extraction of 54 clinical isolates of P. aeruginosa was carried out by alkaline lysis method; and plasmid size estimation was done by using E. coli V517 standard plasmid marker. Fifty-four clinical strains of P. aeruginosa were isolated from ...

  19. Antibacterial Properties of Alkaloid Extracts from Callistemon citrinus and Vernonia adoensis against Staphylococcus aureus and Pseudomonas aeruginosa

    OpenAIRE

    Donald Mabhiza; Tariro Chitemerere; Stanley Mukanganyama

    2016-01-01

    The development of new antibiotics from new chemical entities is becoming more and more expensive, time-consuming, and compounded by emerging strains that are drug resistant. Alkaloids are plant secondary metabolites which have been shown to have potent pharmacological activities. The effect of alkaloids from Callistemon citrinus and Vernonia adoensis leaves on bacterial growth and efflux pump activity was evaluated on Staphylococcus aureus and Pseudomonas aeruginosa. At a concentration of 1....

  20. Alginate is not a significant component of the extracellular polysaccharide matrix of PA14 and PAO1 Pseudomonas aeruginosa biofilms

    OpenAIRE

    Wozniak, Daniel J.; Wyckoff, Timna J. O.; Starkey, Melissa; Keyser, Rebecca; Azadi, Parastoo; O'Toole, George A.; Parsek, Matthew R.

    2003-01-01

    The bacterium Pseudomonas aeruginosa causes chronic respiratory infections in cystic fibrosis (CF) patients. Such infections are extremely difficult to control because the bacteria exhibit a biofilm-mode of growth, rendering P. aeruginosa resistant to antibiotics and phagocytic cells. During the course of infection, P. aeruginosa usually undergoes a phenotypic switch to a mucoid colony, which is characterized by the overproduction of the exopolysaccharide alginate. Alginate overproducti...

  1. Manuka honey treatment of biofilms of Pseudomonas aeruginosa results in the emergence of isolates with increased honey resistance

    OpenAIRE

    Camplin, Aimee L; Maddocks, Sarah E.

    2014-01-01

    Background Medical grade manuka honeys are well known to be efficacious against Pseudomonas aeruginosa being bactericidal and inhibiting the development of biofilms; moreover manuka honey effectively kills P. aeruginosa embedded within an established biofilm. Sustained honey resistance has not been previously documented for planktonic or biofilm P. aeruginosa. Methods Minimum inhibitory concentrations for manuka honey and antibiotics were determined using broth micro-dilution methods. Minimum...

  2. Case Report: Rare occurrence of Pseudomonas aeruginosa osteomyelitis of the right clavicle in a patient with IgA nephropathy

    OpenAIRE

    Damodaran, Aishwarya; Rohit, Anusha; Abraham, Georgi; Nair, Sanjeev; Yuvaraj, Anand; Prasad, Kashi Nath; Dakshinamurthy, K. V.

    2014-01-01

    We describe the case of a 47 year old patient with proven primary IgA nephropathy who presented with osteomyelitis of the medial end of the right clavicle. The patient was not on immunosuppressive medications. He underwent aspiration curettage and CT scan of the clavicle which yielded pus that grew Pseudomonas aeruginosa. Following treatment with appropriate antibiotic therapy the patient presented a complete recovery of the lesion with no loss of renal function. This case highlights the impo...

  3. Effects of Ginseng Treatment on Neutrophil Chemiluminescence and Immunoglobulin G Subclasses in a Rat Model of Chronic Pseudomonas aeruginosa Pneumonia

    OpenAIRE

    Song, Zhijun; Kharazmi, Arsalan; Wu,Hong; Faber, Viggo; Moser, Claus; Krogh Johansen, Helle; Rygaard, Jørgen; Høiby, Niels

    1998-01-01

    Chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) patients is almost impossible to eradicate with antibiotic treatment. In the present study, the effects of treatment with the Chinese herbal medicine ginseng on blood polymorphonuclear leukocyte (PMN) chemiluminescence and serum specific antibody responses were studied in a rat model of chronic P. aeruginosa pneumonia mimicking CF. An aqueous extract of ginseng was administered by subcutaneous injection at a dosage of 25 mg...

  4. Quantitation of Pseudomonas aeruginosa in wound biopsy samples: from bacterial culture to rapid `real-time' polymerase chain reaction

    OpenAIRE

    Pirnay, Jean-Paul; Vos, Daniel De; Duinslaeger, Luc; Reper, Pascal; Vandenvelde, Christian; Cornelis, Pierre; Vanderkelen, Alain

    2000-01-01

    Introduction: Early diagnosis of wound colonisation or prediction of wound sepsis provides an opportunity for therapeutic intervention. There is need for qualitative and quantitative tests that are more rapid than bacterial culture. Pseudomonas aeruginosa results in high morbidity and mortality rates, is inherently resistant to common antibiotics, and is increasingly being isolated as a nosocomial pathogen. We developed three PCR-based methods to detect and quantify P aeruginosa in wound biop...

  5. Swarming of Pseudomonas aeruginosa Is Controlled by a Broad Spectrum of Transcriptional Regulators, Including MetR ▿ †

    OpenAIRE

    Yeung, Amy T. Y.; Torfs, Ellen C. W.; Jamshidi, Farzad; Bains, Manjeet; Wiegand, Irith; Hancock, Robert E. W.; Overhage, Joerg

    2009-01-01

    Pseudomonas aeruginosa exhibits swarming motility on semisolid surfaces (0.5 to 0.7% agar). Swarming is a more than just a form of locomotion and represents a complex adaptation resulting in changes in virulence gene expression and antibiotic resistance. In this study, we used a comprehensive P. aeruginosa PA14 transposon mutant library to investigate how the complex swarming adaptation process is regulated. A total of 233 P. aeruginosa PA14 transposon mutants were verified to have alteration...

  6. Epigenetic Control of Virulence Gene Expression in Pseudomonas aeruginosa by a LysR-Type Transcription Regulator

    OpenAIRE

    Turner, Keith H.; Isabelle Vallet-Gely; Dove, Simon L.

    2009-01-01

    Phenotypic variation within an isogenic bacterial population is thought to ensure the survival of a subset of cells in adverse conditions. The opportunistic pathogen Pseudomonas aeruginosa variably expresses several phenotypes, including antibiotic resistance, biofilm formation, and the production of CupA fimbriae. Here we describe a previously unidentified bistable switch in P. aeruginosa. This switch controls the expression of a diverse set of genes, including aprA, which encodes the secret...

  7. Isolation of Endoglucanase Genes from Pseudomonas fluorescens subsp. cellulosa and a Pseudomonas sp

    OpenAIRE

    Wolff, Bruce R.; Mudry, Terry A.; Glick, Bernard R.; Pasternak, J J

    1986-01-01

    Endoglucanase genes from Pseudomonas fluorescens subsp. cellulosa and Pseudomonas sp. were cloned and characterized. DNA hybridization studies showed that these genes are homologous and that each species has one copy of the gene per genome. The DNA fragment from Pseudomonas sp. codes for, at most, a 23-kilodalton endoglucanase.

  8. STUDY OF METALLO-Β-LACTAMASE PRODUCTION IN CLINICAL ISOLATES OF PSEUDOMONAS AERUGINOSA IN A TEACHING HOSPITAL OF RURAL GUJARAT - INDIA

    Directory of Open Access Journals (Sweden)

    Yagnesh

    2013-05-01

    Full Text Available ABSTRACT: BACKGROUND: Pseudomonas aeruginosa exhibits intrinsic resistanc e to a variety of antimicrobials including beta lactams. Imipenem-res istant Pseudomonas aeruginosa resulting from metallo-β-lactamases production represent a signifi cant and rapidly emerging problem and threat in most part of the world. Detection of metallo-β-l actamase (MBL-producing Pseudomonas aeruginosa is crucial for the optimal antibiotic tr eatment of the seriously ill patients. AIM OF THE STUDY : The study was undertaken to detect Metallo-β-lactam ases among clinical isolates of Pseudomonas aeruginosa in the multidisciplinary tertiary care 520-bedded h ospital. MATERIAL AND METHODS: Two hundred eighty three consecutive clinical isolates of Pseudomonas aeruginosa were subjected to susceptibility testing by disc-di ffusion assay and mini API system (bioMerieux-France. Imipenem resistant Pseudomonas aeruginosa isolates were studied for metallo-β-lactamase production by IPM-EDTA-disk syn ergy test. RESULTS: Imipenem- resistance by disc diffusion method was found in 35 out of 283 isolates (12.3% of Pseudomonas aeruginosa . Of the 35 imipenem-resistant isolates 30 (85.7% we re Metallo-beta-lactamases producers with average zone diameter difference of 16.5 mm between imipenem disk and imipenem plus EDTA disk. Of 35 imipenem-resistant isolates, 21(60% we re from ICU patients and 14(40% were from Wards. CONCLUSION: IPM-EDTA-disk synergy test can be used as a suitabl e screening method in the clinical microbiology laboratory. Presence of M etallo-β-lactamase production among imipenem-resistant Pseudomonas aeruginosa was high in our institution which is disturbing and forces us for prompt infection control measures whi ch are well-organized and continued. Combined approaches of rotational antibiotic therapy and tra ining programmes for the health care workers might be beneficial to fight against these multi dr ug resistant pathogens

  9. [Antibiotic stability in magistral collyria].

    Science.gov (United States)

    Tihărău, A; Voiculescu, E; Vancea, S; Teodorescu, A; Cherecheş, S

    1990-01-01

    The paper presents the results of a study on physicochemical and and microbiological stability of collyria with such antibiotics as: Kanamicin, Oxacilin, Colistin, Erythromycin and Rifampicin. The authors insist on the necessity of preparing the ophthalmic solution with the antibiotics studies, with solvent for eye drops as provided for by RF IX and keeping at +4 degrees C, at dark. PMID:2101048

  10. Antibiotic Prophylaxis in Pediatric Dentistry

    OpenAIRE

    Davydova N.V.; Suyetenkov D.Ye.; Firsova I.V.; Oleynikova N.M.

    2011-01-01

    Identify options for the indications for antibiotic prophylaxis in children's dental reception. The analysis of publications shows that the basis of current trends prevention of postoperative wound infection in pediatric surgery should be measures aimed at eliminating or reducing the influence of risk factors, as well as the use of antibiotic prophylaxis

  11. Antibiotic Prophylaxis in Pediatric Dentistry

    Directory of Open Access Journals (Sweden)

    Davydova N.V.

    2011-03-01

    Full Text Available Identify options for the indications for antibiotic prophylaxis in children's dental reception. The analysis of publications shows that the basis of current trends prevention of postoperative wound infection in pediatric surgery should be measures aimed at eliminating or reducing the influence of risk factors, as well as the use of antibiotic prophylaxis

  12. The Antibiotic Resistance Problem Revisited

    Science.gov (United States)

    Lawson, Michael A.

    2008-01-01

    The term "antibiotic" was first proposed by Vuillemin in 1889 but was first used in the current sense by Walksman in 1941. An antibiotic is defined as a "derivative produced by the metabolism of microorganisms that possess antibacterial activity at low concentrations and is not toxic to the host." In this article, the author describes how…

  13. Erythromycin treatment hinders the induction of oral tolerance to fed ovalbumin

    Directory of Open Access Journals (Sweden)

    Sydney E. Lambert

    2012-07-01

    Full Text Available The mucosal immune system is constantly exposed to antigen, whether it be food antigen, commensal bacteria, or harmful antigen. It is essential that the mucosal immune system can distinguish between harmful and non-harmful antigens, and initiate an active immune response to clear the harmful antigens, while initiating a suppressive immune response (tolerance to non-harmful antigens. Oral tolerance is an immunologic hyporesponsiveness to an orally administered antigen and is important in preventing unnecessary gastrointestinal (GI tract inflammation, which can result in a number of autoimmune and hypersensitivity diseases. Probiotics (beneficial intestinal bacteria, T regulatory cells (Tregs, and dendritic cells (DCs are all essential for generating tolerance. Antibiotics are commonly prescribed to fight infections and often necessary for maintaining health, but they can disrupt the normal intestinal probiotic populations. There is increasing epidemiologic evidence that suggests that antibiotic usage correlates with the development of atopic or irritable bowel disorders, which often result due to a breakdown in immune tolerance. This study investigated the effect of the antibiotic erythromycin on oral tolerance induction to ovalbumin (OVA. The results demonstrated that antibiotic treatment prior to exposure to fed antigen prevents tolerance to that antigen, which may be associated with a reduction in intestinal Lactobacillus populations. Furthermore, antibiotic treatment resulted in a significant decrease in the tolerogenic CD11c+/CD11b+/CD8α- MLN DCs independent of tolerizing treatment. These results provide evidence that antibiotic treatment, potentially through its effects on tolerogenic DCs and intestinal microflora, may contribute to autoimmune and atopic disorders via a breakdown in tolerance and support prior epidemiologic studies correlating increased antibiotic usage with the development of these disorders.

  14. Pseudomonas-follikulitis efter badning i spabad

    DEFF Research Database (Denmark)

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

    2012-01-01

    Pseudomonas aeruginosa is a rare cause of folliculitis. Pseudomonas folliculitis can develop after contact with contaminated water from swimming pools, hot tubs and spa baths. Systemic therapy may be indicated in patients with widespread lesions, systemic symptoms or in immunosuppressed patients....... 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....

  15. [Pseudomonas folliculitis after spa bath exposure].

    Science.gov (United States)

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

    2012-06-25

    Pseudomonas aeruginosa is a rare cause of folliculitis. Pseudomonas folliculitis can develop after contact with contaminated water from swimming pools, hot tubs and spa baths. Systemic therapy may be indicated in patients with widespread lesions, systemic symptoms or in immunosuppressed patients. 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. PMID:22735119

  16. 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

  17. 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.

  18. The Prehistory of Antibiotic Resistance.

    Science.gov (United States)

    Perry, Julie; Waglechner, Nicholas; Wright, Gerard

    2016-01-01

    Antibiotic resistance is a global problem that is reaching crisis levels. The global collection of resistance genes in clinical and environmental samples is the antibiotic "resistome," and is subject to the selective pressure of human activity. The origin of many modern resistance genes in pathogens is likely environmental bacteria, including antibiotic producing organisms that have existed for millennia. Recent work has uncovered resistance in ancient permafrost, isolated caves, and in human specimens preserved for hundreds of years. Together with bioinformatic analyses on modern-day sequences, these studies predict an ancient origin of resistance that long precedes the use of antibiotics in the clinic. Understanding the history of antibiotic resistance is important in predicting its future evolution. PMID:27252395

  19. Antibiotics for acute maxillary sinusitis

    DEFF Research Database (Denmark)

    Ahovuo-Saloranta, Anneli; Borisenko, Oleg V; Kovanen, Niina;

    2008-01-01

    antibiotics from different classes for acute maxillary sinusitis in adults. We included trials with clinically diagnosed acute sinusitis, whether or not confirmed by radiography or bacterial culture. DATA COLLECTION AND ANALYSIS: At least two review authors independently screened search results, extracted......BACKGROUND: Expert opinions vary on the appropriate role of antibiotics for sinusitis, one of the most commonly diagnosed conditions among adults in ambulatory care. OBJECTIVES: We examined whether antibiotics are effective in treating acute sinusitis, and if so, which antibiotic classes are the...... most effective. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2007, Issue 3); MEDLINE (1950 to May 2007) and EMBASE (1974 to June 2007). SELECTION CRITERIA: Randomized controlled trials (RCTs) comparing antibiotics with placebo or...

  20. Disinfectant and antibiotic activities: a comparative analysis in Brazilian hospital bacterial isolates

    Directory of Open Access Journals (Sweden)

    Guimarães Márcia Aparecida

    2000-01-01

    Full Text Available Nosocomial infections are an important cause of morbidity and mortality all over the world. It has been shown that appropriate environmental hygienic and disinfection practices can be very helpful to hospital infection control. The purpose of this study was to evaluate the bactericidal activity of some disinfectants against antibiotic-susceptible and antibiotic-resistant hospital bacterial isolates. The susceptibility of 27 clinical isolates to disinfectants and antibiotics was determined by the Association of Official Analytical Chemist?s (AOAC Use-Dilution method and by the Kirby-Bauer method, respectively. All strains tested were susceptible to sodium hypochlorite, glutaraldehyde and to the association quaternary ammonium - formaldehyde - ethyl alcohol disinfectants. However, the susceptibility of strains to phenol and to one quaternary ammonium compound was variable. Among twenty-one antibiotic-multiresistant strains (methicillin-resistant staphylococci, Enterococcus spp, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Serratia marcescens and Escherichia coli eleven (52% and eight (38% strains were resistant to the quaternary ammonium and phenol compounds, respectively. Among six isolates that demonstrated susceptibility to antibiotics (staphylococci, Enterococcus spp, P. mirabilis, E. cloacae and E. coli two strains (33% showed resistance to these disinfectants. The results demonstrated the lack of correlation between antibiotic-susceptibility and susceptibility to disinfectants in hospital strains.

  1. Antibiotic Resistance of Shigella Species in Iran

    OpenAIRE

    A.Mehr-Movahed; J. Nikkhah

    1987-01-01

    Antibiotic resistance in Shigella species has been showing a rising trend all over the world. This study was performed to discover the state of antibiotic resistance of Shigella species with regards to six common antibiotics in use in Iran.

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

    Directory of Open Access Journals (Sweden)

    Høiby Niels

    2011-04-01

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

  3. Role of Vfr in the regulation of antifungal compound production by Pseudomonas fluorescens FD6.

    Science.gov (United States)

    Zhang, Qingxia; Ji, Yanyan; Xiao, Qi; Chng, Soonie; Tong, Yunhui; Chen, Xijun; Liu, Fengquan

    2016-01-01

    Pseudomonas fluorescens FD6 has been shown to possess many beneficial traits involved in the biocontrol of fungal plant pathogens, such as Botrytis cinerea and Monilinia fructicola. Vfr (virulence factor regulator) a highly conserved global regulator of gram-negative bacteria, such as the human pathogen Pseudomonas aeruginosa, is required for the expression of many important virulence traits. The role of Vfr in the regulation of biocontrol traits, such as the production of antibiotics to control fungal pathogens by antagonistic bacteria, has not been elucidated. This study investigated the effect of a vfr mutant derived from P. fluorescens FD6 to better understand the regulation of some important biocontrol traits associated with the bacterium. Biochemical studies indicated that the production of the antibiotics 2,4-diacetylphloroglucinol, pyrrolnitrin and pyoluteorin, was markedly enhanced in the vfr mutant. The vfr mutation also increased biofilm production, swimming motility and the expression of exopolysaccharide-associated gene (pelA, pslA and pslB) transcripts, but reduced protease production. Wheat rhizosphere and root tip colonization by the vfr mutant was higher than that by the wild type at 7 and 21days after inoculation. These findings demonstrate that Vfr modulates the expression of several key traits and the production of important antibiotics involved in the biocontrol potential of P. fluorescens FD6. PMID:27296968

  4. Analysis of antibiotic resistance in bacteria isolated from the surface microlayer and underlying water of an estuarine environment.

    Science.gov (United States)

    Azevedo, Juliana S N; Araújo, Susana; Oliveira, Cláudia S; Correia, António; Henriques, Isabel

    2013-02-01

    We compared the prevalence of cultivable antibiotic-resistant bacteria and resistance genes in the surface microlayer (SML) and underlying waters (UW) of an estuary. Prevalence of resistant bacteria was determined in antibiotic-supplemented agar. Bacterial isolates from the UW (n=91) and SML (n=80), selected in media without antibiotic, were characterized concerning susceptibility against nine antibiotics. The presence of genes bla(TEM), bla(OXA-B), bla(SHV), bla(IMP), tet(A), tet(B), tet(E), tet(M), cat, sul1, sul2, sul3, aadA, IntI1, IntI2, and IntI3 was assessed by PCR. The variable regions of integrons were sequenced. Ampicillin- and streptomycin-resistant bacteria were significantly more prevalent in SML. Resistance levels among the bacterial collections were generally low, preventing detection of significant differences between SML and UW. The tet(E) gene was detected in two Aeromonas isolates and tet(M) was detected in a Pseudomonas isolate. Gene sul1 was amplified from three Aeromonas isolates. Prevalence of intI genes was 2.11%. Cassette arrays contained genes encoding resistance to aminoglycosides and chloramphenicol. A higher prevalence of antibiotic-resistant bacteria in the SML, although only detectable when bacteria were selected in antibiotic-supplemented agar, suggests that SML conditions select for antibiotic resistance. Results also showed that antibiotic resistance was uncommon among estuarine bacteria and the resistance mechanisms are probably predominantly intrinsic. PMID:23067198

  5. Complete Genome Sequence of Pseudomonas sp. UK4, a Model Organism for Studies of Functional Amyloids in Pseudomonas

    OpenAIRE

    Dueholm, Morten Simonsen; Danielsen, Heidi Nolsøe; Nielsen, Per Halkjær

    2014-01-01

    Here, we present the complete genome of Pseudomonas sp. UK4. This bacterium was the first Pseudomonas strain shown to produce functional amyloids, and it represents a model organism for studies of functional amyloids in Pseudomonas (Fap).

  6. Outcome of patients over 80 years of age on prolonged suppressive antibiotic therapy for at least 6 months for prosthetic joint infection

    Directory of Open Access Journals (Sweden)

    Virginie Prendki

    2014-12-01

    Conclusions: Prolonged suppressive antibiotic therapy is an alternative therapy in elderly patients with PJI when surgery is contraindicated and when the bacteria are susceptible to well-tolerated oral antimicrobial therapy such as beta-lactams.

  7. Resistant patterns of Pseudomonas aeruginosa in a Malaysian teaching hospital

    Institute of Scientific and Technical Information of China (English)

    Zaidah AR; Siti SMN; Zahiruddin WM; Zeehaida M

    2009-01-01

    Objective:Pseudomonas aeruginosa is an opportunistic pathogen and the leading cause of nosocomial infec-tions.Currently a notable increase in the prevalence of multidrug-resistant P.aeruginosa worldwide has been reported in hospitalized patients and was associated with high morbidity and mortality.Methods:A retrospec-tive laboratory based analysis regarding the spectrum and distribution of P.aeruginosa from a wide range of clinical samples in Hospital Universiti Sains Malaysia since January 2003 to December 2007 was done.Re-sults:Altogether,there were 2 308 clinical isolates analyzed.The main sources of P.aeruginosa were from swab,respiratory,urine and blood specimens which accounted for 28.2 %,21.8 %,13.2 % and 12.8 %respectively.Results showed significant reduction in percentage of resistant towards three antibiotic namely ciprofloxacin,ceftazidime and imipenem.However the percentage of pan-resistant P.aeruginosa increased steadily over these years.Conclusion:This data is helpful to the clinician in guiding the choice of appropriate antibiotic to treat P.aeruginosa infection.At the same time,it warrants a more aggressive infection control ac-tivity to be implemented to control the spread of pan resistant strain in this centre.

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

    DEFF Research Database (Denmark)

    Skindersø, Mette Elena

    2008-01-01

    of growth, has the immediate advantage that it does not impose a harsh selection pressure for resistance which is the main drawback of conventional antibiotics. The first two articles included in the present thesis (article 1 and 2) describe the screening of extracts of eukaryotic organisms...... enzymes and components capable of impairing the hosts’ immunity. P. aeruginosa readily assumes the biofilm lifestyle which confers efficient protection against the activity of the host defence system. In addition, P. aeruginosa exhibit an inherent tolerance to many of the antibiotics most commonly used...... times by selective forces. Most of the antibiotics used today originate from natural sources. The general assumption is that antibiotics have evolved in nature to counteract growth of competitors; however, this idea has recently been challenged, and it has been suggested that the ecological role of...

  9. Microbial infection and antibiotic patterns among intensive care unit patients in a tertiary hospital in Central Nepal

    Directory of Open Access Journals (Sweden)

    RK Sanjana

    2013-09-01

    Full Text Available Aims The present study is a fundamental effort to evaluate the bacteriological and antibiotic patterns in the Intensive Care Unit (ICU setting in a tertiary care hospital. This study was carried out to guide the clinician in choosing the appropriate antibiotics and to prevent emergence of multidrug resistance bacteria. Materials and Methods Between March 2009 to Feb 2012, the samples from various ICUs that were submitted to the microbiology laboratory for culture and sensitivity were included in this study. All the organisms were identified morphologically and biochemically by standard laboratory procedure and antibiotic susceptibility pattern was determined by disc diffusion methods. Result Of 3,780 specimens, 2,312 (61.1% isolates were recovered. Single organisms were isolated from 1,746 (75.5% samples while the remaining 566 (24.4% had two or more organisms isolated. Pseudomonas aeruginosa was the most common isolate 819 (35.4%, followed by Klebsiella pneumoniae 637 (27.5%. Antibiotics sensitivity of Pseudomonas aeruginosa showed that almost all isolates were resistant to cephalexin (97.8% and ciprofloxacin (80.3%. However (95.8% of the isolates were sensitive to tobramycin, (92.0% to meropenem & (74.80 % to amikacin. Conclusion It is concluded that Pseudomonas aeruginosa is the predominate pathogen isolated from ICUs of this Hospital. Most of the frequently isolated pathogens are resistant to cephalosporins and quinolone antibiotics as compared to aminoglycosides and carbapenem. Regular surveillance of antibiotic susceptibility pattern is very important for setting a guideline to the clinician in choosing an appropriate therapy of infected patients of ICUs. Journal of College of Medical Sciences-Nepal, 2012, Vol-8, No-3, 1-8 DOI: http://dx.doi.org/10.3126/jcmsn.v8i3.8678

  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. OBJECT

  11. Toleration, Groups, and Multiculturalism

    DEFF Research Database (Denmark)

    Lægaard, Sune

    The chapter considers how groups might be relevant as objects of policies of toleration and the different senses 'group' might have in relation to questions of toleration. The chapter argues that groups can be relevant to toleration in several different ways as objects of toleration. Toleration is...... routinely defined as involving an objection component, a power requirement and an acceptance component. The objection and acceptance components refer to reasons or dispositions of the subjects of toleration, e.g. public authorities deciding how to act in relation to groups. The power condition refers to the...... toleration allows receivers of toleration to enjoy. The chapter shows how groups may be objects of toleration in different ways in relation to each of these components or conditions of toleration. The sense of 'group' relevant to toleration may differ when the group is an object of power, i.e. when others...

  12. Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

    Directory of Open Access Journals (Sweden)

    Roderick I. Mackie

    2013-07-01

    Full Text Available Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

  13. Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

    KAUST Repository

    Hong, Pei-Ying

    2013-07-31

    Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

  14. Natural Hot Spots for Gain of Multiple Resistances: Arsenic and Antibiotic Resistances in Heterotrophic, Aerobic Bacteria from Marine Hydrothermal Vent Fields

    OpenAIRE

    Farias, Pedro; Espírito Santo, Christophe; Branco, Rita; Francisco, Romeu; Santos, Susana; Hansen, Lars; Sorensen, Soren; Morais, Paula V.

    2015-01-01

    Microorganisms are responsible for multiple antibiotic resistances that have been associated with resistance/tolerance to heavy metals, with consequences to public health. Many genes conferring these resistances are located on mobile genetic elements, easily exchanged among phylogenetically distant bacteria. The objective of the present work was to isolate arsenic-, antimonite-, and antibiotic-resistant strains and to determine the existence of plasmids harboring antibiotic/arsenic/antimonite...

  15. New antibiotics for bad bugs: where are we?

    Science.gov (United States)

    Bassetti, Matteo; Merelli, Maria; Temperoni, Chiara; Astilean, Augusta

    2013-01-01

    Bacterial resistance to antibiotics is growing up day by day in both community and hospital setting, with a significant impact on the mortality and morbidity rates and the financial burden that is associated. In the last two decades multi drug resistant microorganisms (both hospital- and community-acquired) challenged the scientific groups into developing new antimicrobial compounds that can provide safety in use according to the new regulation, good efficacy patterns, and low resistance profile. In this review we made an evaluation of present data regarding the new classes and the new molecules from already existing classes of antibiotics and the ongoing trends in antimicrobial development. Infectious Diseases Society of America (IDSA) supported a proGram, called "the '10 × ´20' initiative", to develop ten new systemic antibacterial drugs within 2020. The microorganisms mainly involved in the resistance process, so called the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and enterobacteriaceae) were the main targets. In the era of antimicrobial resistance the new antimicrobial agents like fifth generation cephalosporins, carbapenems, monobactams, β-lactamases inhibitors, aminoglycosides, quinolones, oxazolidones, glycopeptides, and tetracyclines active against Gram-positive pathogens, like vancomycin-resistant S. aureus (VRSA) and MRSA, penicillin-resistant streptococci, and vancomycin resistant Enterococcus (VRE) but also against highly resistant Gram-negative organisms are more than welcome. Of these compounds some are already approved by official agencies, some are still in study, but the need of new antibiotics still does not cover the increasing prevalence of antibiotic-resistant bacterial infections. Therefore the management of antimicrobial resistance should also include fostering coordinated actions by all stakeholders, creating policy guidance, support for

  16. Systemic antibiotic therapy in periodontics

    Directory of Open Access Journals (Sweden)

    Anoop Kapoor

    2012-01-01

    Full Text Available Systemic antibiotics in conjunction with scaling and root planing (SRP, can offer an additional benefit over SRP alone in the treatment of periodontitis, in terms of clinical attachment loss (CAL and pocket depth change, and reduced risk of additional CAL loss. However, antibiotics are not innocuous drugs. Their use should be justified on the basis of a clearly established need and should not be substituted for adequate local treatment. The aim of this review is to discuss the rationale, proper selection, dosage and duration for antibiotic therapy so as to optimize the usefulness of drug therapy.

  17. Antibiotics as CECs: An Overview of the Hazards Posed by Antibiotics and Antibiotic Resistance

    Directory of Open Access Journals (Sweden)

    Geoffrey Ivan Scott

    2016-04-01

    Full Text Available ABSTRACTMonitoring programs have traditionally monitored legacy contaminants but are shifting focus to Contaminants of Emerging Concern (CECs. CECs present many challenges for monitoring and assessment, because measurement methods don't always exist nor have toxicological studies been fully conducted to place results in proper context. Also some CECs affect metabolic pathways to produce adverse outcomes that are not assessed through traditional toxicological evaluations. Antibiotics are CECs that pose significant environmental risks including development of both toxic effects at high doses and antibiotic resistance at doses well below the Minimum Inhibitory Concentration (MIC which kill bacteria and have been found in nearly half of all sites monitored in the US. Antimicrobial resistance has generally been attributed to the use of antibiotics in medicine for humans and livestock as well as aquaculture operations. The objective of this study was to assess the extent and magnitude of antibiotics in the environment and estimate their potential hazards in the environment. Antibiotics concentrations were measured in a number of monitoring studies which included Waste Water Treatment Plants (WWTP effluent, surface waters, sediments and biota. A number of studies reported levels of Antibiotic Resistant Microbes (ARM in surface waters and some studies found specific ARM genes (e.g. the blaM-1 gene in E. coli which may pose additional environmental risk. High levels of this gene were found to survive WWTP disinfection and accumulated in sediment at levels 100-1000 times higher than in the sewerage effluent, posing potential risks for gene transfer to other bacteria.in aquatic and marine ecosystems. Antibiotic risk assessment approaches were developed based on the use of MICs and MIC Ratios [High (Antibiotic Resistant/Low (Antibiotic Sensitive MIC] for each antibiotic indicating the range of bacterial adaptability to each antibiotic to help define the No

  18. Protective effect of DNA vaccine encoding pseudomonas exotoxin A and PcrV against acute pulmonary P. aeruginosa Infection.

    Directory of Open Access Journals (Sweden)

    Mingzi Jiang

    Full Text Available Infections with Pseudomonas aeruginosa have been a long-standing challenge for clinical therapy because of complex pathogenesis and resistance to antibiotics, thus attaching importance to explore effective vaccines for prevention and treatment. In the present study, we constructed a novel DNA vaccine by inserting mutated gene toxAm encoding Pseudomonas Exotoxin A and gene pcrV encoding tip protein of the type III secretion system into respective sites of a eukaryotic plasmid pIRES, named pIRES-toxAm-pcrV, and next evaluated the efficacy of the vaccine in murine acute Pseudomonas pneumonia models. Compared to DNA vaccines encoding single antigen, mice vaccinated with pIRES-toxAm-pcrV elicited higher levels of antigen-specific serum immunoglobulin G (IgG, enhanced splenic cell proliferation and cytokine secretion in response to Pseudomonas aeruginosa antigens, additionally PAO1 challenge in mice airway resulted in reduced bacteria burden and milder pathologic changes in lungs. Besides, it was observed that immunogenicity and protection could be promoted by the CpG ODN 1826 adjuvant. Taken together, it's revealed that recombinant DNA vaccine pIRES-toxAm-pcrV was a potential candidate for immunotherapy of Pseudomonas aeruginosa infection and the CpG ODN 1826 a potent stimulatory adjuvant for DNA vaccination.

  19. Prophylactic antibiotics versus post- operative antibiotics in herniorraphy

    Directory of Open Access Journals (Sweden)

    Abedulla Khan Kayamkani

    2015-07-01

    Full Text Available Postoperative surgical site infections are a major source of illness.  Infection results in longer hospital stay and higher costs.  Uses of preoperative antibiotics have been standardized and are being used routinely in most clinical surgeries and include controversial areas like breast surgery and herniorraphy. Objective of the study is to find out the benefit of prophylactic use of antibiotics in the management of herniorraphy.This project was carried out in a multispeciality tertiary care teaching hospital from 1st-30th April in 2002. Group 1 patients were treated prophylactically half an hour before surgery with single dose of I.V. antibiotics (injection.  Ampicillin 1gm + injection.  Gentamicin 80mg. Group 2 patients were treated post surgery with capsule. Ampicillin 500mg 4 times a day for 7 days and injection. Gentamicin twice a day for first 4 days. In case of group 1 patients only one out of 20 patients (5% was infected.  Whereas in-group 2 patients 5 out of 20 patients (25% were infected. The cost of prophylactic antibiotic treatment was Rs. 25.56 per patient.  The postoperative antibiotic treatment cost was Rs. 220.4 per patient.  That means postoperative treatment is around 8.62 times costlier than prophylactic treatment.             From this study it is evident that prophylactic (preoperative treatment is better than postoperative treatment with antibiotics.

  20. 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.