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Sample records for aureus escherichia coli

  1. Quinolone accumulation in Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.

    OpenAIRE

    McCaffrey, C; Bertasso, A; Pace, J.; Georgopapadakou, N H

    1992-01-01

    The accumulation of quinolones by Escherichia coli JF568, Pseudomonas aeruginosa PAO1, and Staphylococcus aureus ATCC 29213 was measured by a modified fluorometric assay (J. S. Chapman and N. H. Georgopapadakou, Antimicrob. Agents Chemother. 33:27-29, 1989). The quinolones examined were fleroxacin, pefloxacin, norfloxacin, difloxacin, A56620, ciprofloxacin, ofloxacin, and Ro 09-1168. In all three organisms, uptake was complete in less than 5 min and was proportional to extracellular quinolone...

  2. BIOAKTIFITAS MINYAK ATSIRI SEREH Cymbopogon citratus DC. TERHADAP PERTUMBUHAN BAKTERI Escherichia coli DAN Staphylococcus aureus

    OpenAIRE

    Rahman, Hasriani

    2013-01-01

    Penelitian ini mengenai bioaktifitas minyak atsiri sereh Cymbopogon citratus DC. terhadap pertumbuhan bakteri Escherichia coli dan Staphylococcus aureus. Penelitian ini bertujuan untuk mengetahui bioaktifitas dan sifat antibakteri minyak atsiri sereh Cymbopogon citratus DC. terhadap pertumbuhan bakteri Escherichia coli dan Staphylococcus aureus. Pengujian daya hambat dilakukan dengan metode difusi agar menggunakan 5 variasi konsentrasi 100%, 50%, 25%, 12,5% dan 6,25% b/v pada media MHA (Mull...

  3. Antibacterial activity of some commonly used food commodities against escherichia coli, salmonella typhi and staphylococcus aureus

    International Nuclear Information System (INIS)

    The activity of commonly used spices and salt, sugar and pickles against Escherichia coli, Salmonella typhi and staphlococcus aureus was tested. The antibacterial activity was found to be in descending order like coriander>pickles>salt and sugar>clove>black pepper>red chilli against S. typhi and garlic>clove>onion>ginger against S. aureus. (author)

  4. The growth of Staphylococcus aureus and Escherichia coli in low-direct current electric fields

    Institute of Scientific and Technical Information of China (English)

    Dunya Zituni; Heidi Schu tt-Gerowitt; Marion Kopp; Martin Kro nke; Klaus Addicks; Christian Hoffmann; Martin Hellmich; Franz Faber; Wilhelm Niedermeier

    2014-01-01

    Electrical potentials up to 800 mV can be observed between different metallic dental restorations. These potentials produce fields in the mouth that may interfere with microbial communities. The present study focuses on the impact of different electric field strengths (EFS) on the growth of Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922) in vitro. Cultures of S. aureus and E. coli in fluid and gel medium were exposed to different EFS. Effects were determined by calculation of viable counts and measurement of inhibition zones. In gel medium, anodic inhibition zones for S. aureus were larger than those for E. coli at all field strength levels. In fluid medium, the maximum decrease in the viable count of S. aureus cells was at 10 V?m21. Field-treated S. aureus cells presented ruptured cell walls and disintegrated cytoplasm. Conclusively, S. aureus is more sensitive to increasing electric field strength than E. coli.

  5. Antimicrobial effect of Satureja bachtiarica extracts aqueous and ethanolic on Escherichia coli and Staphylococcus aureus

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    Maryam Heidari Sureshjani

    2013-03-01

    Full Text Available In this study antimicrobial effect of extracts evaluated by two methods, “Collins method” and “disk agar diffusion method” on Escherichia coli PTCC 1330 and Staphylococcus aureus PTCC 1337 microorganisms. The minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC for both species determined by using a dilution method. All ethanolic extract concentrations had inhibitory effect in the disk agar diffusion method. In “Collins method” ethanolic extract in 2000 µg/ml concentration, could prevent the growth of both strains on medium. The aqueous extract, had no antimicrobial significant effect in 2000 µg/ml concentration. The ethanolic extract MIC of Satureja bachtiarica for Staphylococcus aureus was 8 mg/ml, and for Escherichia coli was 16 mg/ml. But the aqueous extracts MIC of Satureja bachtiarica for Staphylococcus aureus was 32 mg/ml and for Escherichia coli was 64 mg/ml. The ethanolic extract MBC of Satureja bachtiarica for Staphylococcus aureus was 16 mg/ml, and for Escherichia coli was 32 mg/ml. But the aqueous extracts MBC of Satureja bachtiarica for Staphylococcus aureus was 64 mg/ml and for Escherichia coli was 256 mg/ml. The results indicate that ethanolic extract of Satureja bachtiarica have the greatest effect on gram positive bacterium Staphylococcus aureus PTCC 1337. 

  6. Antimicrobial Effects of Three Tropical Plant Extracts on Staphylococcus Aureus, Escherichia Coli and Candida Albicans

    OpenAIRE

    R.N. Okigbo; Mmeka, E C

    2008-01-01

    Antimicrobial activities of the leaf extracts of Cymbopogon citatrus (lemongrass) and Vernonia amygdalina (bitter leaf) and the seed extracts of Garcinia kola (bitter kola) were carried out. G. kola had effect only on Staphyococcus aureus and Escherichia coli with no inhibition on Candida albicans. Ethanol, cold water and hot water extracts of Vernonia amygdalina and Cymbopogon citratus showed inhibition on the three organism but G. kola ethanol, cold water and hot water extracts only inhibit...

  7. Effect of Organic Acids on Escherichia coli O157:H7 and Staphylococcus aureus Contaminated Meat

    OpenAIRE

    Raftari, M.; Jalilian, F. Azizi; A. S. Abdulamir; Son, R; Z. Sekawi; Fatimah, A.B.

    2009-01-01

    Appropriate and safe antibacterial agents able to decontaminate meat surfaces have long been big concern of meat industry. In an attempt to manage beef carcass contamination, spray wash treatments utilizing three concentrations (1, 1.5 and 2%) of acetic, lactic, propionic and formic acids were performed to evaluate their efficacy in reducing numbers of Escherichia coli O157:H7 and Staphylococcus aureus on meat tissues. The procured beef pieces of freshly slaughtered animals were decontaminate...

  8. Beta-lactamase Escherichia coli and Staphylococcus aureus isolated from chickens in Nigeria

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    Godwin Onyemaechi Egwu

    2010-06-01

    Full Text Available The occurrence of beta-lactamase-producing Escherichia coli and Staphylococcus aureus in chickens was investigated. Specimens (n = 1 300 were collected from 400 chickens and were streaked on MacConkey agar plates. From each plate, presumptive growths of organisms were picked and streaked on eosin methylene blue and Baird-Parker agars, respectively. Typical colonies of E. coli and S. aureus with similar morphologies were identified by biochemical tests. Isolates were tested for beta-lactamase production and antimicrobial susceptibilities. Results indicated that 805 E. coli isolates from which 89 (11% were beta-lactamase-positive and 660 S. aureus from which 58 (8.8% were beta-lactamase-positive. Both isolates showed a high level of resistance to all twelve antibiotics screened. The increased prevalence of antibiotic resistance amongst bacterial organisms is undoubtedly correlated with the discovery and characterisation of multiple, transferrable resistance determinants, such as beta-lactamases, corresponding to their respective phenotypes. The implications of this for humans when handling and/or consuming chickens and chicken products contaminated with strains of such isolates, is a risk of transferrable multi-drug resistance and a failure of treatment. The results of our study indicated that beta-lactamase-producing E. coli and S. aureus are prevalent in chickens in Nigeria.

  9. Beta-lactamase Escherichia coli and Staphylococcus aureus isolated from chickens in Nigeria.

    Science.gov (United States)

    Mamza, Sunday Akidarju; Egwu, Godwin Onyemaechi; Mshelia, Gideon Dauda

    2010-01-01

    The occurrence of beta-lactamase-producing Escherichia coli and Staphylococcus aureus in chickens was investigated. Specimens (n = 1,300) were collected from 400 chickens and were streaked on MacConkey agar plates. From each plate, presumptive growths of organisms were picked and streaked on eosin methylene blue and Baird-Parker agars, respectively. Typical colonies of E. coli and S. aureus with similar morphologies were identified by biochemical tests. Isolates were tested for beta-lactamase production and antimicrobial susceptibilities. Results indicated that 805 E. coli isolates from which 89 (11%) were beta-lactamase-positive and 660 S. aureus from which 58 (8.8%) were beta-lactamase-positive. Both isolates showed a high level of resistance to all twelve antibiotics screened. The increased prevalence of antibiotic resistance amongst bacterial organisms is undoubtedly correlated with the discovery and characterisation of multiple, transferrable resistance determinants, such as beta-lactamases, corresponding to their respective phenotypes. The implications of this for humans when handling and/or consuming chickens and chicken products contaminated with strains of such isolates, is a risk of transferrable multi-drug resistance and a failure of treatment. The results of our study indicated that beta-lactamase-producing E. coli and S. aureus are prevalent in chickens in Nigeria. PMID:20560125

  10. Doxorubicine and antibiotics influence on dynamics of population development of Staphylococcus aureus and Escherichia coli

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    O.G. Shapoval

    2010-03-01

    Full Text Available Infectious complications in oncologic patients often occur as a result of antitumor therapy that demands the prescription of antimicrobic preparations. one of the main infectious agents in oncology is Staphylococci and Escherichia coli. The aim of this work is to study doxorubicine and ceftriaxon influence on dynamics of population development of strains of Staphylococcus aureus, doxorubicine and amikacine - on dynamics of population development of strains of Escherichia coli. Five strains of each type (one-standard and four-clinical cultivated in meatpeptone broth, which contains non-inhibitory concentrations of experimental preparations. in any period of time after the sowing the measurement of optical density of growing cultures has been carried out. it has been determined, that doxorubicine in non-inhibitory concentrations increases overwhelming effect of these antibiotics on dynamics of population development of experimental strains

  11. Antibacterial activity of essential oil of north west Algerian Eucalyptus camaldulensis against Escherichia coli and Staphylococcus aureus

    OpenAIRE

    Bachir Raho Ghalem; Benali Mohamed

    2014-01-01

    Objective: To evaluate the in vitro antimicrobial activities of the crude oil of Eucalyptus camaldulensis (E. camaldulensis) leaves. Methods: The essential oils of E. camaldulensis harvested from the garden of the Health Center in Sidi Bel Abbes city (North West of Algeria), were screened for their antibacterial activities against two clinical bacteria [Escherichia coli (E. coli), Staphylococcus aureus (S. aureus)] by the agar disc diffusion method and broth dilution susceptibi...

  12. Antibacterial activity of essential oil of north west Algerian Eucalyptus camaldulensis against Escherichia coli and Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Bachir Raho Ghalem

    2014-10-01

    Full Text Available Objective: To evaluate the in vitro antimicrobial activities of the crude oil of Eucalyptus camaldulensis (E. camaldulensis leaves. Methods: The essential oils of E. camaldulensis harvested from the garden of the Health Center in Sidi Bel Abbes city (North West of Algeria, were screened for their antibacterial activities against two clinical bacteria [Escherichia coli (E. coli, Staphylococcus aureus (S. aureus] by the agar disc diffusion method and broth dilution susceptibility assay. Results: The diameter of zones of inhibition by the leaf extracts of E. camaldulensis was 10- 31 mm and 10-26 mm respectively for E. coli and S. aureus. Gram positive S. aureus was more resistant to tested essential oil than Gram negative E. coli. Conclusions: The results suggested a potential antimicrobial activity of the essential oil of E. camaldulensis, which may find its application in future research for the food and pharmaceutical industry.

  13. Antibacterial activity of essential oil of north west Algerian Eucalyptus camaldulensis against Escherichia coli and Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Bachir Raho Ghalem; Benali Mohamed

    2014-01-01

    Objective: To evaluate the in vitro antimicrobial activities of the crude oil of Eucalyptuscamaldulensis Methods: The essential oils of E. camaldulensis harvested from the garden of the Health Center in Sidi Bel Abbes city (North West of Algeria), were screened for their antibacterial activities against two clinical bacteria [Escherichia coli (E. coli), Staphylococcus aureus (S. aureus)] by the agar disc diffusion method and broth dilution susceptibility assay.Results:(E. camaldulensis) leaves. 31 mm and 10-26 mm respectively for E. coli and S. aureus. Gram positive S. aureus was more resistant to tested essential oil than Gram negative E. coli. The diameter of zones of inhibition by the leaf extracts of E. camaldulensis was 10-Conclusions: The results suggested a potential antimicrobial activity of the essential oil of E.camaldulensis, which may find its application in future research for the food and pharmaceutical industry.

  14. Antimicrobial Activity of Selected Phytochemicals against Escherichia coli and Staphylococcus aureus and Their Biofilms

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    Joana Monte

    2014-06-01

    Full Text Available Bacteria can be resistant to multiple antibiotics and we are fast approaching a time when antibiotics will not work on some bacterial infections. New antimicrobial compounds are urgently necessary. Plants are considered the greatest source to obtain new antimicrobials. This study aimed to assess the antimicrobial activity of four phytochemicals—7-hydroxycoumarin (7-HC, indole-3-carbinol (I3C, salicylic acid (SA and saponin (SP—against Escherichia coli and Staphylococcus aureus, either as planktonic cells or as biofilms. These bacteria are commonly found in hospital-acquired infections. Some aspects on the phytochemicals mode of action, including surface charge, hydrophobicity, motility and quorum-sensing inhibition (QSI were investigated. In addition, the phytochemicals were combined with three antibiotics in order to assess any synergistic effect. 7-HC and I3C were the most effective phytochemicals against E. coli and S. aureus. Both phytochemicals affected the motility and quorum-sensing (QS activity, which means that they can play an important role in the interference of cell-cell interactions and in biofilm formation and control. However, total biofilm removal was not achieved with any of the selected phytochemicals. Dual combinations between tetracycline (TET, erythromycin (ERY and ciprofloxacin (CIP and I3C produced synergistic effects against S. aureus resistant strains. The overall results demonstrates the potential of phytochemicals to control the growth of E. coli and S. aureus in both planktonic and biofilm states. In addition, the phytochemicals demonstrated the potential to act synergistically with antibiotics, contributing to the recycling of old antibiotics that were once considered ineffective due to resistance problems.

  15. Adhesive polypeptides of Staphylococcus aureus identified using a novel secretion library technique in Escherichia coli

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    Holm Liisa

    2011-05-01

    Full Text Available Abstract Background Bacterial adhesive proteins, called adhesins, are frequently the decisive factor in initiation of a bacterial infection. Characterization of such molecules is crucial for the understanding of bacterial pathogenesis, design of vaccines and development of antibacterial drugs. Because adhesins are frequently difficult to express, their characterization has often been hampered. Alternative expression methods developed for the analysis of adhesins, e.g. surface display techniques, suffer from various drawbacks and reports on high-level extracellular secretion of heterologous proteins in Gram-negative bacteria are scarce. These expression techniques are currently a field of active research. The purpose of the current study was to construct a convenient, new technique for identification of unknown bacterial adhesive polypeptides directly from the growth medium of the Escherichia coli host and to identify novel proteinaceous adhesins of the model organism Staphylococcus aureus. Results Randomly fragmented chromosomal DNA of S. aureus was cloned into a unique restriction site of our expression vector, which facilitates secretion of foreign FLAG-tagged polypeptides into the growth medium of E. coli ΔfliCΔfliD, to generate a library of 1663 clones expressing FLAG-tagged polypeptides. Sequence and bioinformatics analyses showed that in our example, the library covered approximately 32% of the S. aureus proteome. Polypeptides from the growth medium of the library clones were screened for binding to a selection of S. aureus target molecules and adhesive fragments of known staphylococcal adhesins (e.g coagulase and fibronectin-binding protein A as well as polypeptides of novel function (e.g. a universal stress protein and phosphoribosylamino-imidazole carboxylase ATPase subunit were detected. The results were further validated using purified His-tagged recombinant proteins of the corresponding fragments in enzyme-linked immunoassay and

  16. Antimicrobial effects of Lavandula stoechas L. and Rosmarinus officinalis L. extracts on Escherichia coli and Staphylococcus aureus

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    Behrooz Alizadeh Behbahani

    2013-01-01

    Full Text Available In this study Lavandula stoechas L.and Rosmarinus officinalis L. extracted with ethanol 96° and the antimicrobial effects of extracts were evaluated on Escherichia coli PTCC 1330 and Staphylococcus aureus PTCC 1337 by “using the method of Collins” and “disk agar diffusion method”. The results show that ethanolic extract was quite effective in 2000 μg/ml concentration on Escherichia coli PTCC 1330 andStaphylococcus aureus PTCC 1337 and were prevented from growth them on medium. In “disk agar diffusion method”, 20, 40, 60 and 80 % alcoholic extract concentrations, was deterrented effect on Staphylococcus aureus PTCC 1337. TheLavandula stoechas L. and Rosmarinus officinalis L. extract presented the more effective impact on the growth of Staphylococcus aureus PTCC 1337than Escherichia coli PTCC 1330 (pLavandula stoechas L. have the greatest effect on gram-positive bacterium Staphylococcus aureus PTCC 1337. As a result ethanolic extracts of Lavandula stoechas L.andRosmarinus officinalis L., have been strong antimicrobial activity against many food pathogen bacteria. 

  17. Antimicrobial Activities of TiO2 Nanoparticle Against Escherichia coli and Staphylococcus aureus

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    F Barzegary

    2010-04-01

    Full Text Available Introduction: Organic antibacterial materials have been used as insecticides and bactericides for many years. Unfortunately, high temperatures in manufacturing process reduce their antibacterial properties. However, inorganic materials of antibacterial agents have excellent bacterial resistance and thermal stability. Over the past few decades, inorganic nanoparticles whose structures exhibit significantly novel and improved physical, chemical and biological properties and functionality due to their nano-scale size have elicited much interest. methods:The aim of this study was to investigate the antibacterial properties of one kind of nano-specimen (TiO2 nanoparticle against Escherichia coli and Streptococcus aureus. Our study was research perusal. In the first study, the optical density of E. coli and S. aureus cultures were observed in the presence of 0.01%, 0.75% and 1.5% of TiO2. In the second study, 6.3 log CFU/ml of E. coli and S. areus were separately exposed to 1.5% TiO2 at 37 ºC in water. In third study, we studied thew growth of E.coli in solid medium with and without nanoparticles. Results: The presence of 0.01% TiO2 nanoparticles didn’t have a statistically significant effect, but in the presence of 0.75% and 1.5% nanoparticles, the bacterial colonies decreased significantly. In the control group, bacterial cells survival was nearly 13 days, while complete cell death of E. coli was seen when 1.5% TiO2 was applied for 24 hours. The same experiment for S. aureu, showed that complete cell death occured when the bacterial culture was exposed to 1.5% TiO2 for 16 hours.. It was shown that presence of 1.5% TiO2 in the solid medium suppressed the growth of E. coli 5.6 times more (p < 0.001. Discussion: Our findings showed antibacterial effects of TiO2 nanoparticles against both bacteria, but S. areus bacteria were more sensitive to nanoparticles as compared to E. coli bacteria

  18. An unusual gangrenous goat mastitis caused by Staphylococcus aureus, Clostridium perfringens and Escherichia coli co-infection Mastite gangrenosa caprina atípica causada por co-infecção por Staphylococcus aureus, Clostridium perfringens e Escherichia coli

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    M.G. Ribeiro

    2007-06-01

    Full Text Available Relata-se, pela primeira vez no Brasil, a ocorrência de mastite gangrenosa caprina atípica causada pela co-infecção por Staphylococcus aureus, Clostridium perfringens e Escherichia coli em uma cabra da raça Boer, na segunda semana de lactação. Descrevem-se os achados clínicos, os procedimentos de diagnóstico microbiológico e a conduta terapêutica.

  19. An unusual gangrenous goat mastitis caused by Staphylococcus aureus, Clostridium perfringens and Escherichia coli co-infection Mastite gangrenosa caprina atípica causada por co-infecção por Staphylococcus aureus, Clostridium perfringens e Escherichia coli

    OpenAIRE

    M.G. Ribeiro; G.H.B. Lara; S.D. Bicudo; A.V.G. Souza; T. Salerno; A.K. Siqueira; J.S. Geraldo

    2007-01-01

    Relata-se, pela primeira vez no Brasil, a ocorrência de mastite gangrenosa caprina atípica causada pela co-infecção por Staphylococcus aureus, Clostridium perfringens e Escherichia coli em uma cabra da raça Boer, na segunda semana de lactação. Descrevem-se os achados clínicos, os procedimentos de diagnóstico microbiológico e a conduta terapêutica.

  20. Retention in Treated Wastewater Affects Survival and Deposition of Staphylococcus aureus and Escherichia coli in Sand Columns

    OpenAIRE

    Li, Jiuyi; Zhao, Xiaokang; Tian, Xiujun; Li, Jin; Sjollema, Jelmer; Wang, Aimin

    2015-01-01

    The fate and transport of pathogenic bacteria from wastewater treatment facilities in the Earth's subsurface have attracted extensive concern over recent decades, while the impact of treated-wastewater chemistry on bacterial viability and transport behavior remains unclear. The influence of retention time in effluent from a full-scale municipal wastewater treatment plant on the survival and deposition of Staphylococcus aureus and Escherichia coli strains in sand columns was investigated in th...

  1. Uji Aktivitas Antibakteri Ekstrak Metanol Bunga Rosella (Hibiscus sabdariffa L) Terhadap Bakteri Escherichia coli dan Stapylococcus aureus

    OpenAIRE

    Yani, Rizki Fitri

    2010-01-01

    The study of antibacterial methanolic extract of Rosella flower (Hibiscus sabdariffa L.) to the growth of Escherichia coli and Stapylococcus aureus, was conducted. Agar diffusion method was used in this study. Treatment used was methanolic extract of Roselle flower concentration which were 10 %, 20%, 30%, 40% and 50% whereas cloramfenicol 30 µg was used as a comparison. The results showed that methanolic extracts of roselle flower have different activity in inhibiting the growth of Escheri...

  2. ANTIBACTERIAL EFFECT OF GARLIC (ALLIUM SATIVUM) AND GINGER (ZINGIBER OFFICINALE) AGAINST STAPHYLOCOCCUS AUREUS, SALMONELLA TYPHI, ESCHERICHIA COLI AND BACILLUS CEREUS

    OpenAIRE

    Bandna Chand

    2013-01-01

    Antibacterial activity of extracts of Allium sativum (garlic) and Zingiber officinale (ginger) has been evaluated against four different bacteria namely Escherichia coli, Salmonella Typhi, Staphylococcus aureus and Bacillus cereus. Two methods were used to determine the antimicrobial activity of garlic and ginger extracts namely disk diffusion method and agar well diffusion method. Garlic extract exhibited excellent antibacterial activity against all four test organisms while ginger extract s...

  3. Zinc ascorbate has superoxide dismutase-like activity and in vitro antimicrobial activity against Staphylococcus aureus and Escherichia coli

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    Iinuma K

    2012-09-01

    Full Text Available Katsuhiro Iinuma, Isami TsuboiBML General Laboratory, Kawagoe, Saitama, JapanBackground: Acne vulgaris is a common dermatological disease, and its pathogenesis is multifactorial.Objective: We examined whether the ascorbic acid derivative zinc ascorbate has superoxide dismutase (SOD-like activity. SOD is an enzyme that controls reactive oxygen species production. In addition, the in vitro antimicrobial activity of zinc ascorbate against the Gram-positive bacterium Staphylococcus aureus and the Gram-negative bacterium Escherichia coli was tested either alone or in combination with a variety of antimicrobial agents; their fractional inhibitory concentration index was determined using checkerboard tests.Methods: The SOD-like activity was measured in comparison with other ascorbic acid derivatives (ascorbic acid, magnesium ascorbyl phosphate, and sodium ascorbyl phosphate and zinc. The antimicrobial susceptibility of twelve strains each of S. aureus and E. coli isolated from patients with dermatological infections was tested, in comparison to a type strain of S. aureus and E. coli.Results: Zinc ascorbate had significant (P < 0.001 SOD-like activity compared with other ascorbic acid derivatives and zinc. Moreover, it showed antimicrobial activity against a type strain of S. aureus and E. coli, and its concentration (0.064% and 0.128% for S. aureus and E. coli, respectively was sufficiently lower than the normal dose (5% of other ascorbic acid derivatives. Furthermore, combinations of zinc ascorbate with clindamycin, erythromycin, and imipenem against S. aureus (average fractional inhibitory concentration, 0.59–0.90, and with imipenem against E. coli (average fractional inhibitory concentration, 0.64 isolated from patients with dermatological infections showed an additive effect.Conclusions: Our results provide novel evidence that zinc ascorbate may be effective for acne treatment.Keywords: superoxide dismutase, reactive oxygen species, antimicrobial

  4. Effects of combination of magnesium and zinc oxide nanoparticles and heat on Escherichia coli and Staphylococcus aureus bacteria in milk

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    M. Kimiaee Sadr

    2016-01-01

    Full Text Available Objective: The objective of this study was to investigate the antibacterial activities of combination of MgO and ZnO nanoparticles in the presence of heat against Escherichia coli and Staphylococcus aureus. Materials and Methods:Bacteria were grown on either agar or broth media followed by the addition of ZnO and MgO nanoparticles. Then the combined effect of ZnO and MgO nanoparticles was investigated.  Furthermore, the media containing nanoparticles were treated with mild heat and their synergistic antibacterial activity was investigated against E. coli and S. aureus in milk. Results: The data showed that the nanoparticles used in this study had no effect on the bacteria in the agar medium. However, the results showed that ZnO and MgO nanoparticles resulted in a significant decrease in the number of E. coli (P

  5. Seasonal Variation of Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae Bacteremia According to Acquisition and Patient Characteristics

    DEFF Research Database (Denmark)

    Gradel, Kim Oren; Nielsen, Stig Lønberg; Pedersen, Court; Knudsen, Jenny Dahl; Østergaard, Christian; Arpi, Magnus; Jensen, Thøger Gorm; Kolmos, Hans Jørn; Søgaard, Mette; Lassen, Annmarie Touborg; Schønheyder, Henrik Carl

    Seasonal variation analysis. METHODS In 3 Danish health regions (2.3 million total inhabitants), patients with bacteremia were identified from 2000 through 2011 using information from laboratory information systems. Analyses were confined to Escherichia coli, Staphylococcus aureus, and Streptococcus...... pneumoniae. Additional data were obtained from the Danish National Hospital Registry for the construction of admission histories and calculation of the Charlson comorbidity index (CCI). Bacteremias were categorized as community acquired, healthcare associated (HCA), and hospital acquired. We defined multiple....... coli, 6,924 S. aureus, and 4,884 S. pneumoniae bacteremia cases. For E. coli, the seasonal variation was highest for community-acquired cases (PTT ratio, 1.24; 95% CI, 1.17-1.32), was diminished for HCA (PTT ratio, 1.14; 95% CI, 1.04-1.25), and was missing for hospital-acquired cases. No seasonal...

  6. An Evaluation of the Antimicrobial Synergy of Garlic (Allium sativum and Utazi (Gongronema latifolium on Escherichia coli and Staphylococcus aureus

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    Eja, M. E.

    2011-01-01

    Full Text Available As part of the on-going search for potent and resistance-free antimicrobial medicinal plants, the antimicrobial and synergistic effects of the plants, Allium sativum (E1 and Gongronema latifolium (E2 on Escherichia coli and Staphylococcus aureus were investigated. The sensitivities of E. coli and S. aureus to E1 and E2 and the minimum inhibitory concentrations of the plant extracts, individually and in combination with themselves, and with ciprofloxacin (CPX and ampicillin (AMP, were tested using standard procedures. E1 and E2 individually showed appreciable antimicrobial effect (zones of inhibition > 16mm. The combination of E1 and E2 against the test organisms was not effective due to antagonism between E1 and E2. E1 or E2 when combined with CPX, completely suppressed the effect of CPX against E. coli, and rather produced additive effect on S. aureus similar to the combination of E2 and AMP against S. aureus, although CPX alone was more effective than either E1 or E2, unlike AMP. Synergism was observed in the combination of E1 and AMP against S. aureus. It is concluded that synergism associated with the combination of medicinal plants is doubtful. However, the synergistic or additive effect between garlic and conventional drugs to some strains of bacteria which are resistant to some conventional drugs, gives hope of fighting drug resistance.

  7. Nanorough titanium surfaces reduce adhesion of Escherichia coli and Staphylococcus aureus via nano adhesion points.

    Science.gov (United States)

    Lüdecke, Claudia; Roth, Martin; Yu, Wenqi; Horn, Uwe; Bossert, Jörg; Jandt, Klaus D

    2016-09-01

    Microbial adhesion to natural and synthetic materials surfaces is a key issue e.g. in food industry, sewage treatment and most importantly in the biomedical field. The current development and progress in nanoscale structuring of materials surfaces to control microbial adhesion requires an advanced understanding of the microbe-material-interaction. This study aimed to investigate the nanostructure of the microbe-material-interface and link it to microbial adhesion kinetics as function of titanium surface nanoroughness to gain new insight into controlling microbial adhesion via materials' surface nanoroughness. Adhesion of Escherichia coli and Staphylococcus aureus was statistically significantly reduced (p≤0.05) by 55.6 % and 40.5 %, respectively, on physical vapor deposited titanium thin films with a nanoroughness of 6nm and the lowest surface peak density compared to 2nm with the highest surface peak density. Cross-sectioning of the microbial cells with a focused ion beam (FIB) and SEM imaging provided for the first time direct insight into the titanium-microbe-interface. High resolution SEM micrographs gave evidence that the surface peaks are the loci of initial contact between the microbial cells and the material's surface. In a qualitative model we propose that the initial microbial adhesion on nanorough surfaces is controlled by the titanium surface peak density via nano adhesion points. This new understanding will help towards the design of materials surfaces for controlling microbial adhesion. PMID:27288816

  8. Escherichia Coli

    Science.gov (United States)

    Goodsell, David S.

    2009-01-01

    Diverse biological data may be used to create illustrations of molecules in their cellular context. I describe the scientific results that support a recent textbook illustration of an "Escherichia coli cell". The image magnifies a portion of the bacterium at one million times, showing the location and form of individual macromolecules. Results…

  9. ANTIBACTERIAL EFFECT OF GARLIC (ALLIUM SATIVUM AND GINGER (ZINGIBER OFFICINALE AGAINST STAPHYLOCOCCUS AUREUS, SALMONELLA TYPHI, ESCHERICHIA COLI AND BACILLUS CEREUS

    Directory of Open Access Journals (Sweden)

    Bandna Chand

    2013-02-01

    Full Text Available Antibacterial activity of extracts of Allium sativum (garlic and Zingiber officinale (ginger has been evaluated against four different bacteria namely Escherichia coli, Salmonella Typhi, Staphylococcus aureus and Bacillus cereus. Two methods were used to determine the antimicrobial activity of garlic and ginger extracts namely disk diffusion method and agar well diffusion method. Garlic extract exhibited excellent antibacterial activity against all four test organisms while ginger extract showed antibacterial activity against Bacillus cereus and Staphylococcus aureus only. In addition, agar well diffusion method showed higher zone in inhibition when compared with the zone of inhibition produced by the spice of same concentration against the test microorganism by disk diffusion method. Antibiotic sensitivity of the four different bacteria was tested with commercially available antibiotics namely Ciprofloxacin; Oxytetracycline; Vancomycin; Streptomycin; Gentamicin; Tetracycline; Novobiocin; Amikacin and Penicillin G. Penicillin G produced the highest zone of inhibition of 40.00±0.00against Staphylococcus aureus and the lowest zone of inhibition of 0.00±0.00against Escherichia coli.

  10. Preparation and antibacterial properties of laser-generated silver–anatase nanocomposite film against Escherichia coli and Staphylococcus aureus

    International Nuclear Information System (INIS)

    Anatase-based titanium dioxide (TiO2) naturally possesses a well recognized antibacterial effect under ultraviolet excitation. However, anatase modified with silver nanoparticles (Ag NPs) exhibits even stronger antibacterial action in natural daylight. The purpose of our present research is to evaluate the photocatalytic antibacterial effects of laser-generated silver–anatase nanocomposite film against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). A sol–gel TiO2 precursor was spin-coated on a clean glass slide and silver ions were self-adsorbed from aqueous solution. A pulsed beam of KrF excimer laser (248 nm, 13 ns) was traversed over the amorphous film, leading to the crystallization of the anatase and formation of cubic as well as hexagonal Ag NPs. A scanning transmission electron microscope analysis revealed a 30–40 nm anatase crystallite size, whereas an average size of 9.6 nm was obtained from Ag NPs. The photo-absorption of plain anatase was red-shifted to 516 nm with the addition of Ag NPs after the laser treatment. Moreover, no colonies of E. coli and S. aureus cells were observed to survive after 60 min of contact with the laser-modified silver–anatase films in the dark and in daylight conditions. (paper)

  11. Uji Efek Antibakteri Ekstrak Etanol Kulit Batang Salam {Syzigium polyanthum (Wight Walp} terhadap Staphylococcus aureus dan Escherichia coli secara Invitro

    Directory of Open Access Journals (Sweden)

    Ikhsan Amanda Putra

    2015-05-01

    Full Text Available AbstrakTumbuhan salam (Syzygium polyanthum (Wight Walp. telah dikenal sejak dahulu untuk mengobati berbagai penyakit. Bagian tumbuhan yang dapat dimanfaatkan sebagai obat selain daun adalah bagian kulit batang. Beberapa penelitian yang telah dilakukan terbukti bahwa daun salam memiliki efek antibakteri. Tujuan penelitian ini adalah untuk mengetahui bagaimana efek antibakteri dari kulit batang salam. Penelitian ini bersifat deskriptif menggunakan metode difusi agar. Konsentrasi ekstrak yang digunakan adalah 25%, 50%, 75%, dan 100%. Hasil penelitian menunjukkan bahwa ekstrak etanol kulit batang salam memiliki efek antibakteri terhadap Staphylococcus aureus dengan konsentrasi 25%, 50%, 75%, dan 100% memberikan daya hambat terhadap pertumbuhan bakteri sebesar 12 mm, 13,67 mm, 12,33 mm, dan 9 mm, sedangkan pada konsentrasi yang sama untuk Escherichia coli tidak terlihat daya hambat terhadap pertumbuhan bakteri. Konsentrasi ekstrak yang paling efektif dalam menghambat S. aureus adalah konsentrasi 50%, dimana konsentrasi 75% dan 100% kurang efektif.Kata kunci: uji efek antibakteri, kulit batang salam, staphylococcus aureus, eschericia coli AbstractSalam plants (Syzygium polyanthum (Wight Walp. Salam plants have been known since ancient to treat various diseases. The parts of the plant that can be used as drug are bark. From the research that has been conducted has proven that Salam leaves has an antibacterial effect. The objective of this study was to determine the antibacterial effect of salam bark.This was a descriptive study by using agar diffusion method. The concentration of the extract used was 25%, 50%, 75%, and 100%. The results showed that the ethanol extract of Salam bark has antibacterial effects to Staphylococcus aureus with the concentration of 25%, 50%, 75%, and 100% gives the inhibition of the growth of bacteria on 12 mm, 13.67 mm, 12.33 mm, and the 9 mm, while at the same concentration for Escherichia coli was no bacterial inhibition

  12. Uji Daya Hambat Sabun Cair Cuci Tangan pada Restoran Waralaba di Kota Padang Terhadap Pertumbuhan Bakteri Escherichia coli dan Staphylococcus aureus Secara In Vitro

    Directory of Open Access Journals (Sweden)

    Anisha Fazlisia

    2014-09-01

    Full Text Available AbstrakSabun cair cuci tangan terbukti dapat menghambat pertumbuhan bakteri Escherichia coli dan Staphylococcus aureus. Sebagian besar restoran waralaba di Kota Padang menyediakan sabun cair cuci tangan yang telah diencerkan. Proses pengenceran mengubah kemampuan sabun dalam menghambat pertumbuhan bakteri. Penelitian bertujuan untuk menguji daya hambat sabun cair cuci tangan pada restoran waralaba di Kota Padang terhadap pertumbuhan E. coli dan S. aureus. Sampel diambil dari empat restoran waralaba dan diuji dengan metode difusi. Hasil penelitian menunjukkan bahwa keempat sabun dapat menghambat pertumbuhan S. aureus namun hanya sebagian yang memiliki daya hambat terhadap E. coli. Median daya hambat pertumbuhan E. coli dan S. aureus pada setiap periode yaitu 0, 7.4, 7.3 dan 0, 26.1, 23.3. Nilai maksimum daya hambat pertumbuhan E.coli dalam tiga periode yaitu 19.5, 35.4, 27.1 dan 20.7, 40.2, 36.6 untukS. aureus. Daya hambat minimum terhadap kedua bakteri adalah 0.00. Hal tersebut dapat dipengaruhi komposisi dan konsentrasi antiseptik, antibakteri, pH sabun, pengenceran dan struktur dinding sel bakteri. Disimpulkan bahwa sabun cair cuci tangan yang diuji memiliki kemampuan lebih besar dalam menghambat pertumbuhan S.aureus daripada E.coli.Kata kunci: sabun cair cuci tangan, restoran, pengenceran, uji daya hambat, pertumbuhan bakteriAbstractLiquid hand soaps proved to inhibit Escherichia coli and Staphylococcus aureus bacterial growth. In Padang, most of Restaurants provide diluted liquid hand soaps. Research found dilution changed soap ability to inhibit bacterial growth. The purpose of this study was to examine the ability of Padang City Restaurants’ liquid hand soaps to inhibit E. coli and S. aureus bacterial growth. The samples were taken from four restaurants and examined by using diffusion method. The results showed all of them could inhibit S. aureus but only a half inhibited Escherichia coli bacterial growth. Median for E. coli and S

  13. Survival and growth of Salmonella Typhimurium, Escherichia coli O157:H7 and Staphylococcus aureus in eggplant dip during storage.

    Science.gov (United States)

    Osaili, Tareq M; Al-Nabulsi, Anas A; Jaradat, Ziad; Shaker, Reyad R; Alomari, Dalia Z; Al-Dabbas, Maher M; Alaboudi, Akram R; Al-Natour, Mohammad Q; Holley, Richard A

    2015-04-01

    Eggplant dip is an internationally popular appetizer, prepared in some instances under uncertain hygienic conditions with inconsistent refrigeration. This study examined the effects of citric acid on the survival of pathogenic microorganisms (Salmonella Typhimurium, Escherichia coli O157:H7 and Staphylococcus aureus) and naturally present organisms (lactic acid bacteria, LAB, aerobic bacteria, APC and yeast and mold, YM) in eggplant dip during storage. Eggplant dip with 0, 0.2, 0.4, 0.6 or 0.8% citric acid was inoculated with S. Typhimurium, E. coli O157:H7 or S. aureus and stored at 4, 10 and 21 °C for ≤15 d. Throughout the study, the survival of the inoculated microorganisms was monitored, and LAB, APC, YM numbers and pH were determined. There was no significant (p>0.05) effect of citric acid on inoculated S. Typhimurium and E. coli O157:H7. Salmonella and E. coli O157:H7 survived >7d with little reduction in viability. Reduction of S. aureus viability increased with citric acid concentration and reached>3.0 log10 CFU/g by 15 d at 4 °C. Citric acid had no effect (p>0.05) on the background YM during storage at 4, 10 and 21 °C or LAB stored at 4 and 10 °C, while at 21 °C, 0.6 and 0.8% citric acid significantly reduced LAB. Citric acid had no effect (p>0.05) on the APC in samples stored at 4 °C but it had significant effects on samples stored at 10 and 21 °C. Work reported showed that the use of citric acid at 0.4-0.8% can inhibit the growth of S. aureus in eggplant dip, but adequate refrigeration is essential to minimize risk from this and other pathogens in this product. PMID:25590259

  14. Antibacterial potential of essential oils of the needles of Pinus halepensis against Staphylococcus aureus and Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Ghalem Bachir Raho

    2014-01-01

    Objective:To examine the in vitro antimicrobial activities of essential oil of the needles of Pinus halepensis (P. halepensis). Methods:The antibacterial activity of essential oil of the needles of P. halepensis was determined using the agar well diffusion technique and disc diffusion method against Staphylococcus aureus ATCC 25923, and Escherichia coli ATCC 25922. Results:The diameter of zones of inhibition exhibited by the essential oil was between 6 and 17 mm. The essential oils was compared favorably with gentamycin used as a standard control. The minimum inhibitory concentration determined by the agar well diffusion method was 0.52 mg/mL for Staphylococcus aureus and 2.15 mg/mL for Escherichia coli. The minimum bactericidal concentration of the oils against the two microorganisms was 4.17 mg/mL. Conclusions:The results obtained from this study reveal that P. halepensis essential oils possess antibacterial activities and can be used as antimicrobial agents in the search for new drugs.

  15. Antimicrobial activity of Lippia sidoides Cham. (Verbenaceae essential oil against Staphylococcus aureus and Escherichia coli Atividade antimicrobiana do óleo essencial de Lippia sidoides Cham. (Verbenaceae contra Staphylococcus aureus e Escherichia coli

    Directory of Open Access Journals (Sweden)

    C.E Castro

    2011-01-01

    Full Text Available The antibacterial effect of Lippia sidoides (rosemary pepper essential oil was tested against the bacteria Staphylococcus aureus and Escherichia coli isolated from homemade Minas cheese produced in Brazil. The Minimum Inhibitory Concentration (MIC determined in the Dilution Test was 13 µL oil mL-1 for both bacteria, which characterizes inhibitory action in broth for a 24-hour interaction period. The Minimum Bactericidal Concentration (MBC determined in the Suspension Test, with one minute of contact, was 25 µL oil mL-1 for both tested bacteria, obtaining at this concentration a bactericidal effect of 99.9% on the viable bacterial cells from each sample. Results demonstrated the bacterial activity of Lippia sidoides essential oil against S. aureus and E. coli, suggesting its use as an antibacterial agent in foods.O efeito antibacteriano do óleo essencial da Lippia sidoides (alecrim-pimenta foi testado contra as bactérias Staphylococcus aureus e Escherichia coli isoladas de queijo minas artesanal, produzido no Brasil. A Concentração Inibitória Mínima (CIM determinada por Teste de Diluição foi de 13 µL de óleo mL-1 para as duas bactérias, o que caracteriza ação inibitória em caldo durante vinte quatro horas de interação. A Concentração Bactericida Mínima (CBM determinada através de Teste de Suspensão, com um minuto de contato, foi de 25 µL de óleo mL-1 para ambas as bactérias testadas, obtendo-se a esta concentração o efeito bactericida de 99,9% sobre as células bacterianas viáveis em cada uma das amostras. Os resultados demonstraram atividade bactericida do óleo essencial de Lippia sidoides contra S. aureus e E. coli, sugerindo a possibilidade do uso como agente antibacteriano em alimentos.

  16. Early transcriptional events in the udder and teat after intra-mammary Escherichia coli and Staphylococcus aureus challenge.

    Science.gov (United States)

    Petzl, Wolfram; Günther, Juliane; Mühlbauer, Katharina; Seyfert, Hans-Martin; Schuberth, Hans-Joachim; Hussen, Jamal; Sauter-Louis, Carola; Hafner-Marx, Angela; Zerbe, Holm

    2016-05-01

    Intra-mammary bacterial infections can result in harmful clinical mastitis or subclinical mastitis with persistent infections. Research during the last decades closely examined the pathophysiology of inflamed udders. Initial events after pathogen perception but before the onset of mastitis have not been examined in vivo The objective of this study was to develop a mastitis model in cows by monitoring initial transcriptional pathogen-specific host response before clinical signs occur. We applied a short-term infection model to analyse transcripts encoding chemokines, cytokines and antimicrobial molecules in the teat cistern (TC) and lobulo-alveolar parenchyma (LP) up to 3 h after challenge with E and Staphylococcus aureus Both pathogens elicited an immune reaction by 1 h after challenge. Escherichia coli induced all analysed factors (CCL20, CXCL8, TNF, IL6, IL12B, IL10, LAP, S100A9); however, S. aureus failed to induce IL12B, IL10, LAP and S100A9 expression. The E. coli-induced up-regulation was 25-105 times greater than that after S. aureus challenge. Almost all the responses were restricted to the TC. The short-term mastitis model demonstrates that a divergent pathogen-specific response is generated during the first h. It confirms that the first transcripts are generated in the TC prior to a response in the LP. PMID:27012912

  17. Uji Aktivitas Antibakteri Ekstrak Etanol Biji Kelor (Moringaoleifera Lam.) terhadap Bakteri Staphylococcus aureus dan Escherichia coli

    OpenAIRE

    Manurung, Putri Mariana

    2016-01-01

    Kelor, Moringa oleifera Lam. (Moringaceae) is a highly valued plant for whole body, because it has a high nutritional value. Moringa seeds contain bioactive compounds rhamnosyloxy - benzyl - isothiocyanate , which is able to neutralize the particles of mud as well, so it could potentially be used as a natural coagulant to clean water . Its ability to precipitate many metal ions dissolved and harmful bacteria such as Escherichia coli , and Salmonella typymurium Streptocoocus faecalis . This...

  18. Evaluation of Antimicrobial Effects of Three Medicinal Plants in South of Iran against the Staphylococcus Aureus, Pseudomonas Aeruginosa and Escherichia Coli.

    Directory of Open Access Journals (Sweden)

    Mustafa Baloch

    2014-07-01

    Full Text Available Nowadays, natural treatment of bacterial diseases using substances which are herbal is of utmost importance. In the present study effects of three antibacterial medicinal plants in south of Iran against the separated Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli from Clinical samples and standard strains was investigated. Hydro-alcoholic extracts of Ziziphora tenuior, Origanum Vulgare and Mentha longifolia were prepared after being dried at shade. In the following the antibacterial activity of the extracts against separated Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli from clinical samples of the Shiraz hospitals and standard samples using disk agar diffusion method was investigated and the drug resistance in the studied samples was conducted using the standard Kirby-Bauer method. The growth of the all studied Staphylococcus aureus and Escherichia coli was stopped by hydro-alcoholic extracts of Mentha longifolia, Ziziphora tenuior and Origanum Vulgare but Pseudomonas aeruginosa showed growth zone of inhibition only against Origanum Vulgare. From statistical viewpoint Origanum Vulgare had also the most antimicrobial effect against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli in the all studied samples (P<0.05. Extracts of Mentha longifolia, Origanum Vulgare and Ziziphora tenuior have a potent antibacterial effect against the gram-positive and gram-negative. But on the nosocomial pathogen, Pseudomonas aeruginosa, only Origanum Vulgare has growth inhibitory effect.

  19. Variant innate immune responses of mammary epithelial cells to challenge by Staphylococcus aureus, Escherichia coli and the regulating effect of taurine on these bioprocesses.

    Science.gov (United States)

    Zheng, Liuhai; Xu, Yuanyuan; Lu, Jinye; Liu, Ming; Bin Dai; Miao, Jinfeng; Yin, Yulong

    2016-07-01

    Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are important pathogens causing subclinical and clinical bovine mastitis, respectively. Taurine, an organic acid found in animal tissues, has been used for the treatment of various superficial infections and chronic inflammations. We challenged a bovine mammary epithelial cell (MEC) line (MAC-T) or a mouse mammary epithelial cell line (EpH4-Ev) with either E. coli or S. aureus and compared the responses of MECs to these 2 pathogens. We also examined the regulatory effects of taurine on these responses. Receptor analyses showed that both TLR2 and TLR4 are upregulated upon exposure to either E. coli or S. aureus. Taurine pre-treatment dampened upregulation to some extent. E. coli and S. aureus stimulated comparable levels of ROS, which could be inhibited by taurine pre-treatment. E. coli infection elicited a dramatic change in iNOS expression. Taurine significantly decreased iNOS expression in the S. aureus challenged group. Protein microarray demonstrated that 32/40 and 8/40 inflammatory molecules/mediators were increased after E. coli or S. aureus challenge, respectively. The fold changes of most molecules were higher in the E. coli infection group than that in the S. aureus infection group. Taurine negatively regulated the inflammatory profile in both bacterial infections. Pro-inflammatory cytokines (such as TNF-α) connected with TLR activation were down-regulated by taurine pre-treatment. The influence of TAK-242 and OxPAPC on cytokine/molecule expression profiles to E. coli challenge are different than to S. aureus. Some important factors (MyD88, TNF-α, IL-1β, iNOS and IL-6) mediated by TLR activation were suppressed either in protein microarray or special assay (PCR/kits) or both. TAK-242 restrained ROS production and NAGase activity similar to the effect of taurine in E. coli challenge groups. The detection of 3 indices (T-AOC, SOD and MDA) reflecting oxidative stress in vivo, showed that

  20. Comparative Evaluation of the Modulation of Antibiotic-Activity against Strains of Escherichia coli and Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Henrique D. M. Coutinho

    2015-09-01

    Full Text Available Introduction: Combining multiple drugs is an strategy used to combat the dissemination of pathogenic and drug resistant bacteria. However, the misuse of these drugs against bacteria have caused the selection of more resistant specimens called multidrug-resistant bacteria. Objective: In this work we evaluated the antibiotic activity of claritromicin, gentamicin, ciprofloxacin and imipenen, alone or associating one by one, against strains of Escherichia coli and Staphylococcus aureus. Material and methods: The minimal inhibitory concentration (mic was performed us­ing the microdilution assay. Based in the mic values, the antibiotic effect of the drugs alone and in association were determined. Results: The association between the drugs demonstrated the synergism against the bacterial strains. Conclusion: The use of the combined antibiotic-therapy can be positively performed, but additional studies have to be conducted first for proving that its use is safe.

  1. Changes in antimicrobial susceptibility patterns of Klebsiella pneumoniae, Escherichia coli and Staphylococcus aureus over the past decade

    DEFF Research Database (Denmark)

    Barfod, Toke Seierøe; Wibroe, Elisabeth Arnberg; Braüner, Julie Vestergaard;

    2015-01-01

    INTRODUCTION: Development of antimicrobial resistance is an ongoing and increasing problem. To provide the best possible treatment for patients it is crucial that clinicians are aware of the local antimicrobial susceptibility patterns. The aim of this study was to present an overview of the...... percentage of bacterial isolates that are covered by the most commonly used antibiotics in the area of Copenhagen and to provide clinicians with a practical tool to help chose the right antimicrobial treatment for their patients. METHODS: We conducted a study of all bacteria isolates tested for antimicrobial...... susceptibility at Hvidovre Hospital, Denmark, from 2004 to 2008. Due to a suspected rise in resistance in Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae after this period, updated data for these bacteria are shown for selected antibiotics until 2014. The department receives samples from...

  2. Uji Efek Antibakteri Minyak Jintan Hitam (Nigella Sativa Dalam Kapsul yang Dijual Bebas Selama Tahun 2012 di Kota Padang Terhadap Bakteri Staphylococcus aureus dan Escherichia coli Secara In Vitro

    Directory of Open Access Journals (Sweden)

    Gezha Utama Putra

    2015-05-01

    Full Text Available AbstrakJintan Hitam atau Nigella sativa diketahui memiliki kemampuan sebagai antibakteri, seperti terhadap Staphylococcus aureus dan Escherichia coli. Kedua bakteri ini memiliki sifat yang berbeda namun memiliki kesamaan dari penyakit yang disebabkannya. Tujuan penelitian ini adalah untuk membandingkan efek antibakteri produk minyak jintan hitam (Nigella sativa dalam bentuk kapsul antara bakteri Staphylococcus aureus dan Escherechia coli secara in vitro. Penelitian ini dilakukan pada bulan Januari 2012 - Desember 2012 di Laboratorium Mikrobiologi, Fakultas Kedokteran Universitas Andalas. Penelitian ini menunjukkan bahwa semua sampel jintan hitam yang digunakan tidak memiliki efek antibakteri terhadap Escherichia coli dan semua sampel tersebut memiliki efek antibakteri yang bervariasi pada Staphylococcus aureus. Analisis Anova menunjukkan bahwa masing-masing sampel minyak Nigella sativa memberikan efek berbeda secara signifikan pada pertumbuhan Staphylococcus aureus, bahkan enam diantaranya memiliki efek yang lebih baik daripada Cepoperazon (25 mm sebagai kontrol yang digunakan.Kata kunci: Nigella sativa, efek antibakteri, Staphylococcus aureus, Escherichia coli. AbstractBlack Cumin or Nigella sativa known have the capability as antibacterial, such as to Staphylococcus aureus and Escherichia coli. Both of these bacteria have different properties but have similarities from diseases they may cause. The objective of this study was to compare anti-bacterial effects of black cumin oil (Nigella sativa which has been packaged in capsules towards Staphylococcus aureus and Escherichia coli in vitro The research was conducted in January 2012 to December 2012 at the Microbiology laboratory, Medicine Faculty of Andalas University. The results of this research indicate that all black cumin samples that are used did not have antibacterial effect against Escherichia coli and all samples had antibacterial effects on Staphylococcus aureus with germ-free area

  3. Antibiotic Sensitivity Pattern of Staphylococcus aureus and Escherichia coli Isolated from Bovine Fresh Milk (POLA SENSITIVITAS ANTIBIOTIK TERHADAP STAPHYLOCOCCUS AUREUS DAN ESCHERICHIA COLI YANG DIISOLASI DARI SUSU SAPI SEGAR

    Directory of Open Access Journals (Sweden)

    Lucia Ratna Winata Muslimin

    2016-01-01

    Full Text Available The aims of this study were to determine the sensitivity of S.aureus and E. coli isolated fromfresh milk against against several antibiotics and to determine the safety of the milk for humancomsumsion. Milk was collected from milking diary cow and was used for the bacterial isolation. E.coli were were identified using Total Plate Count (TPC, Gram staining, their growth on Endo Agarand Eosin MethyleneBlue Agar, Biochemical analysis including glucose, lactose, sucrose,maltose, andsorbitol would be followed by Sorbitol Mac Conkey Agar Test for the identification of E.coliO157:H7.The isolation and identification of S.aureus were performed using Gram stain, TPC, growth on BairdParker Agar and Mannitol Salt Agar. S. aureus and S. epidermidis were differentiated by coagulaseand catalase tests. The antibiotic sensitivity tests for both S. aureus and E.coli were carried out usingthe following antibiotics: ampicillin, bacitracin, vancomycin, cefoperazone, ceftriaxone, cefotamine,cefuroxime, cefepime, cefazoline, ceftazidime, chloramphenicol, tetracycline, doxycycline, amikacin,kanamycin, neomycin, ertapenem, meropenem, imipenem, erythromycin, gentamycin, nalidixic acid,ciprofloxacin, levofloxacine, norfloxacine, ofloxacin, and novobiocin. Fresh milk obtained from thefarm was positive for S.aureus and E.coli and resistant to most antibiotics tested. The best antibioticsfor S. aureus were imipenem (54.1 mm, ampicillin (42.3 mm, cefazolin (41.6 mm, doxycycline (41.15mm, and for E.coli were Imipenem (30.1 mm, ertapenem (29.5 mm, and meropenem (25.35 mm. Thebovine fresh milk examined was contaminated by S.aureus and E.coli and to some extent, were alsoresistant to most antibiotics tested.

  4. Diurnal differences in milk composition and its influence on in vitro growth of Staphylococcus aureus and Escherichia coli in bovine quarter milk.

    Science.gov (United States)

    Eisenberg, S W F; Boerhout, E M; Ravesloot, L; Daemen, A J J M; Benedictus, L; Rutten, V P M G; Koets, A P

    2016-07-01

    In experimental intramammary inoculation studies, it has been observed that mastitis susceptibility is influenced, among others, by cow factors. To identify milk characteristics leading to these differences, quarter milk samples of morning and evening milk were collected and analyzed for their composition (protein, fat, lactose, urea, lactoferrin, lactoperoxidase, and β-lactoglobulin concentrations), somatic cell count, and antibodies against Staphylococcus aureus. Furthermore, in vitro growth of S. aureus and Escherichia coli in fresh quarter milk samples was determined. All measured parameters differed significantly between quarters and also between morning and evening milk with the exception of lactose levels. In addition, quantitative growth of S. aureus and E. coli was significantly different in morning milk compared with evening milk. Mixed model analysis revealed that replication of S. aureus was negatively associated with the presence of fat, S. aureus-specific IgG1 antibodies, contamination of the milk sample and morning milk. Replication of E. coli was negatively associated with fat concentrations, and positively associated with morning milk. The significant difference between morning and evening milk supports the theory that changes in milk composition influence bacterial growth. Although all determined milk components differed significantly between quarters and in time no significant association with bacterial growth could be identified with the exception of fat for both studied species and IgG1 titers for S. aureus. The negative association of fat with bacterial growth was assumed to occur due to activation of lipolysis by milk handling and can most likely be neglected for in vivo relevance. The fact that S. aureus-specific IgG1 titers were negatively associated with S. aureus growth in vitro encourages the ongoing effort to develop a vaccine against S. aureus-induced mastitis. PMID:27132103

  5. Visible light photocatalytic antibacterial activity of Ni-doped and N-doped TiO2 on Staphylococcus aureus and Escherichia coli bacteria.

    Science.gov (United States)

    Ananpattarachai, Jirapat; Boonto, Yuphada; Kajitvichyanukul, Puangrat

    2016-03-01

    The Ni-doped and N-doped TiO2 nanoparticles were investigated for their antibacterial activities on Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria. Their morphological features and characteristics such as particle size, surface area, and visible light absorbing capacity were compared and discussed. Scanning electron microscopy, X-ray diffraction, and UV-visible spectrophotometry were used to characterize both materials. The inactivation of E. coli (as an example of Gram-negative bacteria) and S. aureus (as an example of Gram-positive bacteria) with Ni-doped and N-doped TiO2 was investigated in the absence and presence of visible light. Antibacterial activity tests were conducted using undoped, Ni-doped, and N-doped TiO2. The N-doped TiO2 nanoparticles show higher antibacterial activity than Ni-doped TiO2. The band gap narrowing of N-doped TiO2 can induce more visible light absorption and leads to the superb antibacterial properties of this material. The complete inactivation time for E. coli at an initial cell concentration of 2.7 × 10(4) CFU/mL was 420 min which is longer than the 360 min required for S. aureus inactivation. The rate of inactivation of S. aureus using the doped TiO2 nanoparticles in the presence of visible light is greater than that of E. coli. The median lethal dose (LD50) values of S. aureus and E. coli by antibacterial activity under an 18-W visible light intensity were 80 and 350 mg/ml for N-doped TiO2, respectively. PMID:26028352

  6. Antibiotic Sensitivity Pattern of Staphylococcus aureus and Escherichia coli Isolated from Bovine Fresh Milk (POLA SENSITIVITAS ANTIBIOTIK TERHADAP STAPHYLOCOCCUS AUREUS DAN ESCHERICHIA COLI YANG DIISOLASI DARI SUSU SAPI SEGAR)

    OpenAIRE

    Lucia Ratna Winata Muslimin; Firzan Nainu; Rochmat Himawan

    2016-01-01

    The aims of this study were to determine the sensitivity of S.aureus and E. coli isolated fromfresh milk against against several antibiotics and to determine the safety of the milk for humancomsumsion. Milk was collected from milking diary cow and was used for the bacterial isolation. E.coli were were identified using Total Plate Count (TPC), Gram staining, their growth on Endo Agarand Eosin MethyleneBlue Agar, Biochemical analysis including glucose, lactose, sucrose,maltose, andsorbitol woul...

  7. In vitro antibacterial activity of leaf extracts of Zehneria scabra and Ricinus communis against Escherichia coli and methicillin resistance Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Bereket; Abew; Samuel; Sahile; Feleke; Moges

    2014-01-01

    Objective:To evaluate the antibacterial activities of the crude leaves extracts of Zehneria scabra(Z.scabra) and Ricinus communis(R.communis) against Escherichia coli(E.coli).Staphylococcus aureus(S.aureus) and methicillin resistance 5.aureus.Methods:The crude powdered leaves of Z.scabra and R.communis were extracted successively by organic solvents in increasing polarity[benzene,chloroform:acetone(1:1),70%alcohol and distilled water].The antibacterial susceptibility of the crude leaves extracts of were tested against standard strains of E.coli(ATCC 25922) and S.aureus(ATCC 2923) and clinical isolates of E.coli,S.aureus and methicillin resistance 5.aureus using agar well diffusion method.Results:In Z.scabra and R.communis leaf extracts,the most sensitive standard strain was S.aureus with an inhibition zone of(14.00±1.20) mm and(15.90±2.13) mm,respectively.The minimum inhibitory concentration(MIC) values of Z.scabra extracts against test organisms ranged from 1.95mg/mL for extract 3 in clinical and standard strains of 5.aureus to 250 mg/mL for extract 1 and 4in clinical and standard strains of E.coli.The MIC values of R.communis extracts against test organisms ranged from 1.95 mg/mL for extract 2 and 3 standard strains of S.aureus to 250 mg/mL for extract 1 in clinical isolate of E.coli.Most of the minimum bactericidal concentration and MIC values of plant extracts were almost similar particularly in R.communis,or minimum bactericidal concentration equal to one dilution factor less than MIC value of the extracts mainly in Z.scabra.Conclusions:The potency of plant extracts against test organisms were depend on different organic solvents used.Clinical isolate of bacterial pathogens showed less zones of diameter compared to the standard strains.Gram-positive had wide inhibition zones than Gram-negative bacteria.Further studies should be carried out to isolate the pure compounds and standardization of the methods of plant extracts for an in vitro testing.

  8. In vitro antibacterial activity of leaf extracts of Zehneria scabra and Ricinus communis against Escherichia coli and methicillin resistance Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Bereket Abew; Samuel Sahile; Feleke Moges

    2014-01-01

    Objective: To evaluate the antibacterial activities of the crude leaves extracts of Zehneria scabra (Z. scabra) and Ricinus communis (R. communis) against Escherichia coli (E. coli), Staphylococcusaureus (S. aureus) and methicillin resistance S. aureus. Methods: The crude powdered leaves of Z. scabra and R. communis were extracted successively by organic solvents in increasing polarity [benzene, chloroform:acetone (1:1), 70% alcohol and distilled water]. The antibacterial susceptibility of the crude leaves extracts of were tested against standard strains of E. coli (ATCC 25922) and S. aureus (ATCC 2923) and clinical isolates of E. coli, S.aureus and methicillin resistance S. aureus using agar well diffusion method. Results: In Z. scabra and R. communis leaf extracts, the most sensitive standard strain was S. aureus with an inhibition zone of (14.00±1.20) mm and (15.90±2.13) mm, respectively. The minimum inhibitory concentration (MIC) values of Z. scabra extracts against test organisms ranged from 1.95 mg/mL for extract 3 in clinical and standard strains of S. aureus to 250 mg/mL for extract 1 and 4 in clinical and standard strains of E. coli. The MIC values of R. communis extracts against test organisms ranged from 1.95 mg/mL for extract 2 and 3 standard strains of S. aureus to 250 mg/mL for extract 1 in clinical isolate of E. coli. Most of the minimum bactericidal concentration and MIC values of plant extracts were almost similar particularly in R. communis, or minimum bactericidal concentration equal to one dilution factor less than MIC value of the extracts mainly in Z. scabra. Conclusions: The potency of plant extracts against test organisms were depend on different organic solvents used. Clinical isolate of bacterial pathogens showed less zones of diameter compared to the standard strains. Gram-positive had wide inhibition zones than Gram-negative bacteria. Further studies should be carried out to isolate the pure compounds and standardization of the methods

  9. Comparison of four commercial DNA extraction kits for PCR detection of Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Staphylococcus aureus in fresh, minimally processed vegetables.

    Science.gov (United States)

    Elizaquível, P; Aznar, R

    2008-10-01

    Four commercial DNA extraction methods, PrepMan Ultra (Applied Biosystems), InstaGene Matrix (BioRad), DNeasy Tissue kit (Qiagen), and UltraClean (MoBio), were tested for PCR detection of Listeria monocytogenes, Escherichia coli O157: H7, Salmonella, and Staphylococcus aureus in fresh, minimally processed vegetables. For comparative purposes, sensitivity assays with specific PCRs were carried out after DNA extraction with the four methods in green pepper, broccoli, and onion artificially inoculated with the four pathogens separately. As confirmed by statistical analysis, the DNeasy Tissue kit rendered the highest sensitivity values in the three matrices assayed for Salmonella, L. monocytogenes, and E. coli O157:H7 and in onion for S. aureus. Despite being the most expensive of the methods compared, the DNeasy Tissue Kit can be successfully applied for any of the four most commonly studied pathogens, thus saving time and overall reducing the cost of the analysis. PMID:18939762

  10. Nitric oxide-releasing polysaccharide derivative exhibits 8-log reduction against Escherichia coli, Acinetobacter baumannii and Staphylococcus aureus.

    Science.gov (United States)

    Pegalajar-Jurado, Adoracion; Wold, Kathryn A; Joslin, Jessica M; Neufeld, Bella H; Arabea, Kristin A; Suazo, Lucas A; McDaniel, Stephen L; Bowen, Richard A; Reynolds, Melissa M

    2015-11-10

    Health-care associated infections (HAIs) and the increasing number of antibiotic-resistant bacteria strains remain significant public health threats worldwide. Although the number of HAIs has decreased by using improved sterilization protocols, the cost related to HAIs is still quantified in billions of dollars. Furthermore, the development of multi-drug resistant strains is increasing exponentially, demonstrating that current treatments are inefficient. Thus, the quest for new methods to eradicate bacterial infection is increasingly important in antimicrobial, drug delivery and biomaterials research. Herein, the bactericidal activity of a water-soluble NO-releasing polysaccharide derivative was evaluated in nutrient broth media against three bacteria strains that are commonly responsible for HAIs. Data confirmed that this NO-releasing polysaccharide derivative induced an 8-log reduction in bacterial growth after 24h for Escherichia coli, Acinetobacter baumannii and Staphylococcus aureus. Additionally, the absence of bacteria after 72h of exposure to NO illustrates the inability of the bacteria to recover and the prevention of biofilm formation. The presented 8-log reduction in bacterial survival after 24h is among the highest reduction reported for NO delivery systems to date, and reaches the desired standard for industrially-relevant reduction. More specifically, this system represents the only water-soluble antimicrobial to reach such a significant bacterial reduction in nutrient rich media, wherein experimental conditions more closely mimic the in vivo environment than those in previous reports. Furthermore, the absence of bacterial activity after 72h and the versatility of using a water-soluble compound suggest that this NO-releasing polysaccharide derivative is a promising route for treating HAIs. PMID:26374942

  11. Reprint of: Nitric oxide-releasing polysaccharide derivative exhibits 8-log reduction against Escherichia coli, Acinetobacter baumannii and Staphylococcus aureus.

    Science.gov (United States)

    Pegalajar-Jurado, Adoracion; Wold, Kathryn A; Joslin, Jessica M; Neufeld, Bella H; Arabea, Kristin A; Suazo, Lucas A; McDaniel, Stephen L; Bowen, Richard A; Reynolds, Melissa M

    2015-12-28

    Health-care associated infections (HAIs) and the increasing number of antibiotic-resistant bacteria strains remain significant public health threats worldwide. Although the number of HAIs has decreased by using improved sterilization protocols, the cost related to HAIs is still quantified in billions of dollars. Furthermore, the development of multi-drug resistant strains is increasing exponentially, demonstrating that current treatments are inefficient. Thus, the quest for new methods to eradicate bacterial infection is increasingly important in antimicrobial, drug delivery and biomaterials research. Herein, the bactericidal activity of a water-soluble NO-releasing polysaccharide derivative was evaluated in nutrient broth media against three bacteria strains that are commonly responsible for HAIs. Data confirmed that this NO-releasing polysaccharide derivative induced an 8-log reduction in bacterial growth after 24h for Escherichia coli, Acinetobacter baumannii and Staphylococcus aureus. Additionally, the absence of bacteria after 72 h of exposure to NO illustrates the inability of the bacteria to recover and the prevention of biofilm formation. The presented 8-log reduction in bacterial survival after 24h is among the highest reduction reported for NO delivery systems to date, and reaches the desired standard for industrially-relevant reduction. More specifically, this system represents the only water-soluble antimicrobial to reach such a significant bacterial reduction in nutrient rich media, wherein experimental conditions more closely mimic the in vivo environment than those in previous reports. Furthermore, the absence of bacterial activity after 72 h and the versatility of using a water-soluble compound suggest that this NO-releasing polysaccharide derivative is a promising route for treating HAIs. PMID:26686492

  12. Uji Efek Antibakteri Minyak Jintan Hitam (Nigella Sativa) Dalam Kapsul yang Dijual Bebas Selama Tahun 2012 di Kota Padang Terhadap Bakteri Staphylococcus aureus dan Escherichia coli Secara In Vitro

    OpenAIRE

    Gezha Utama Putra; Aziz Djamal; Machdawaty Masri

    2015-01-01

    AbstrakJintan Hitam atau Nigella sativa diketahui memiliki kemampuan sebagai antibakteri, seperti terhadap Staphylococcus aureus dan Escherichia coli. Kedua bakteri ini memiliki sifat yang berbeda namun memiliki kesamaan dari penyakit yang disebabkannya. Tujuan penelitian ini adalah untuk membandingkan efek antibakteri produk minyak jintan hitam (Nigella sativa) dalam bentuk kapsul antara bakteri Staphylococcus aureus dan Escherechia coli secara in vitro. Penelitian ini dilakukan pada bulan J...

  13. Absence in Bacillus subtilis and Staphylococcus aureus of the sequence-specific deoxyribonucleic acid methylation that is conferred in Escherichia coli K-12 by the dam and dcm enzymes.

    OpenAIRE

    Dreiseikelmann, Brigitte; Wackernagel, Wilfried

    1981-01-01

    Restriction analysis of plasmid pHV14 deoxyribonucleic acid isolated from Escherichia coli K-12, Bacillus subtilis, and Staphylococcus aureus with restriction endonucleases MboI, Sau3AI, and EcoRII was used to study the methylation of those nucleotide sequences which in E. coli contain the major portions of N6-methyladenine and 5-methylcytosine. The results showed that neither B. subtilis nor S. aureus methylates deoxyribonucleic acid at the same sites and nucleotides which are recognized and...

  14. Modelling for antimicrobial activities of ionic liquids towards Escherichia coli, Staphylococcus aureus and Candida albicans using linear free energy relationship descriptors.

    Science.gov (United States)

    Cho, Chul-Woong; Park, Jeong-Soo; Stolte, Stefan; Yun, Yeoung-Sang

    2016-07-01

    To predict antimicrobial activities i.e., minimal inhibitory concentration (MIC) and minimal biocidal concentration (MBC) for ionic liquids (ILs) against Escherichia coli, Staphylococcus aureus and Candida albicans, six quantitative structure-activity relationship (QSAR) models were developed using linear free energy relationship (LFER) descriptors calculated by density functional theory and conductor screening model. The LFER descriptors are excess molar refraction, dipolarity/polarizability, H-bonding acidity, H-bonding basicity, McGowan volume, cationic interaction, and anionic interaction. By excluding some descriptors with ignorable contributions to training set, components of the QSAR models were simplified. Their estimated predictabilities were in R(2)=0.900, standard error (SE; in log unit of μM)=0.430 for log 1/MIC of E. coli, R(2)=0.934, SE=0.370 for log 1/MBC of E. coli, R(2)=0.910, SE=0.470 for log 1/MIC of S. aureus, R(2)=0.947, SE=0.350 for log 1/MBC of S. aureus, R(2)=0.892, SE=0.362 for log 1/MIC of C. albicans and R(2)=0.803, SE=0.233 for log 1/MBC of C. albicans. Then, except for log 1/MBC of C. albicans due to lack of data points, the models were validated by comparing between observed and calculated values of test set; its checked correlations were all within R(2) of 0.921. PMID:26974242

  15. Preparation of ciprofloxacin-coated zinc oxide nanoparticles and their antibacterial effects against clinical isolates of Staphylococcus aureus and Escherichia coli

    DEFF Research Database (Denmark)

    Seif, Sepideh; Kazempour, Zarah Bahri; Pourmand, Mohammad Reza;

    2011-01-01

    carbonyl group in ciprofloxacin is actively involved in forming chemical - rather than physical - bonds with zinc oxide nanoparticles. Also the antibacterial activity of free zinc oxide nanoparticles and ciprofloxacin-coated zinc oxide nanoparticles have been evaluated against different clinical isolates...... pure ciprofloxacin) considerably enhanced the antibacterial activity of zinc oxide nanoparticles against different isolates of Staphylococcus aureus and Escherichia coli (4 to 32 fold increase). The result is of particular value, since it demonstrates that, by using biocompatible zinc oxide...... nanoparticles in combination therapy, lower amounts of antibiotics may be needed...

  16. X-Ray Absorption Near-Edge Structure (XANES) Spectroscopy Study of the Interaction of Silver Ions with Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli

    OpenAIRE

    Bovenkamp, Gudrun Lisa; Zanzen, Ulrike; Krishna, Katla Sai; Hormes, Josef; Prange, Alexander

    2013-01-01

    Silver ions are widely used as antibacterial agents, but the basic molecular mechanism of this effect is still poorly understood. X-ray absorption near-edge structure (XANES) spectroscopy at the Ag LIII, S K, and P K edges reveals the chemical forms of silver in Staphylococcus aureus and Escherichia coli (Ag+ treated). The Ag LIII-edge XANES spectra of the bacteria are all slightly different and very different from the spectra of silver ions (silver nitrate and silver acetate), which confirms...

  17. Synergistic Effects of Honey and Propolis toward Drug Multi-Resistant Staphylococcus Aureus, Escherichia Coli and Candida Albicans Isolates in Single and Polymicrobial Cultures

    Directory of Open Access Journals (Sweden)

    Noori AL-Waili, Ahmad Al-Ghamdi, Mohammad Javed Ansari, Y. Al-Attal, Khelod Salom

    2012-01-01

    Full Text Available Background: Propolis and honey are natural bee products with wide range of biological and medicinal properties. The study investigated antimicrobial activity of ethyl alcohol extraction of propolis collected from Saudi Arabia (EEPS and from Egypt (EEPE, and their synergistic effect when used with honey. Single and polymicrobial cultures of antibiotic resistant human pathogens were tested.Material and methods; Staphylococcus aureus (S. aureus,, Escherichia coli (E. coli and Candida albicans (C.albicans were cultured in 10-100% (v/v honey diluted in broth, or 0.08-1.0% (weight/volume EEPS and EEPE diluted in broth. Four types of polymicrobial cultures were prepared by culturing the isolates with each other in broth (control and broth containing various concentrations of honey or propolis. Microbial growth was assessed on solid plate media after 24 h incubation.Results; EEPS and EEPE inhibited antibiotic resistant E.coli, and S.aureus, and C.albicans in single and polymicrobial cultures. S.aureus became more susceptible when it was cultured with E.coli or C.albicans or when all cultured together. C.albicans became more susceptible when it was cultured with S.aureus or with E.coli and S. aureus together. The presence of ethyl alcohol or honey potentiated antimicrobial effect of propolis toward entire microbes tested in single or polymicrobial cultures. EEPS had lower MIC toward E.coli and C.albicans than EEPE. When propolis was mixed with honey, EEPS showed lower MIC than EEPE. In addition, honey showed lower MIC toward entire microbes when mixed with EEPS than when it was mixed with EEPE.Conclusion; 1 propolis prevents the growth of the microorganisms in single and mixed microbial cultures, and has synergistic effect when used with honey or ethyl alcohol, 2 the antimicrobial property of propolis varies with geographical origin, and 3 this study will pave the way to isolate active ingredients from honey and propolis to be further tested individually

  18. Limit of detection of genomic DNA by conventional PCR for estimating the load of Staphylococcus aureus and Escherichia coli associated with bovine mastitis.

    Science.gov (United States)

    Chandrashekhar, K M; Isloor, Shrikrishna; Veeresh, B H; Hegde, Raveendra; Rathnamma, D; Murag, Shivaraj; Veeregowda, B M; Upendra, H A; Hegde, Nagendra R

    2015-11-01

    Detection of mastitis-associated bacteria can be accomplished by culturing or by molecular techniques. On the other hand, rapid and inexpensive methods to enumerate bacterial load without culturing can be better achieved by molecular methods. Staphylococcus aureus and Escherichia coli are the predominant bacterial pathogens associated with bovine mastitis. Here, we describe the application of conventional PCR for the limit of detection (LOD) of genomic DNA of S. aureus and E. coli based on single-copy genes. The selected genes were thermonuclease (nuc), aureolysin (aur), and staphopain A (scpA) for S. aureus and β-D-glucuronidase A (uidA), cytochrome d oxidase (cyd), and rodA (a gene affecting cell shape and methicillin sensitivity) for E. coli. The LOD was 5.3, 15.9, and 143 pg for aur, nuc, and scpA genes, corresponding to S. aureus genomic copies of 1.75 × 10(3), 5.16 × 10(3), and 4.71 × 10(4), respectively. The LOD was 0.45, 12.3 and 109 pg for uidA, rodA and cyd genes, corresponding to E. coli genome copies of 8.91 × 10(1), 2.43 × 10(3), and 2.16 × 10(4), respectively. Application of uidA and aur PCRs to field strains revealed that as low as approximately 100 genome copies of E. coli and 1000-10,000 copies of S. aureus could be detected. This study is the first to report LOD of genomic DNA using conventional PCR for aur and scpA genes of S. aureus, and rodA and cyd genes of E. coli. The results should be useful for developing assays to assess bacterial load in milk and to determine the load that contributes to subclinical or clinical mastitis. PMID:25773783

  19. Taxonomy Icon Data: Escherichia coli [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Escherichia coli Escherichia coli Escherichia_coli_L.png Escherichia_coli_NL.png Escherichia_coli..._S.png Escherichia_coli_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Escherichia+coli...&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Escherichia+coli&t=NL http://biosciencedbc.jp/taxono...my_icon/icon.cgi?i=Escherichia+coli&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Escherichia+coli&t=NS ...

  20. Effects of Flower and Fruit Extracts of Melastoma malabathricum Linn. on Growth of Pathogenic Bacteria: Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella typhimurium

    Directory of Open Access Journals (Sweden)

    Siti Nurhadis Che Omar

    2013-01-01

    Full Text Available Melastoma malabathricum Linn. is a shrub that comes with beautiful pink or purple flowers and has berries-like fruits rich in anthocyanins. This study was carried out with the aim to evaluate the inhibitory activities of different concentrations of the M. malabathricum Linn. flower and fruit crude extracts against Listeria monocytogenes IMR L55, Staphylococcus aureus IMR S244, Escherichia coli IMR E30, and Salmonella typhimurium IMR S100 using the disc diffusion method. The lowest concentrations of the extracts producing inhibition zones against the test microorganisms were used to determine their minimum inhibitory concentrations (MICs and minimum bactericidal concentrations (MBCs. In addition, the growth of Listeria monocytogenes IMR L55 and Staphylococcus aureus IMR S244 grown in medium supplemented with the respective extracts at different temperatures (4°C, 25°C, and 37°C and pHs (4, 6, 7, and 8 was determined.

  1. Recurrent Escherichia coli bacteremia.

    OpenAIRE

    Maslow, J.N.; Mulligan, M E; Arbeit, R D

    1994-01-01

    Escherichia coli is the most common gram-negative organism associated with bacteremia. While recurrent E. coli urinary tract infections are well-described, recurrent E. coli bacteremia appears to be uncommon, with no episodes noted in multiple series of patients with gram-negative bacteremias. We report on 5 patients with recurrent bloodstream infections identified from a series of 163 patients with E. coli bacteremia. For each patient, the isolates from each episode were analyzed by pulsed-f...

  2. Seasonal Variation of Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae Bacteremia According to Acquisition and Patient Characteristics: A Population-Based Study.

    Science.gov (United States)

    Gradel, Kim Oren; Nielsen, Stig Lønberg; Pedersen, Court; Knudsen, Jenny Dahl; Østergaard, Christian; Arpi, Magnus; Jensen, Thøger Gorm; Kolmos, Hans Jørn; Søgaard, Mette; Lassen, Annmarie Touborg; Schønheyder, Henrik Carl

    2016-08-01

    OBJECTIVE Seasonal variation is a characteristic of many infectious diseases, but relatively little is known about determinants thereof. We studied the impact of place of acquisition and patient characteristics on seasonal variation of bacteremia caused by the 3 most common pathogens. DESIGN Seasonal variation analysis. METHODS In 3 Danish health regions (2.3 million total inhabitants), patients with bacteremia were identified from 2000 through 2011 using information from laboratory information systems. Analyses were confined to Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Additional data were obtained from the Danish National Hospital Registry for the construction of admission histories and calculation of the Charlson comorbidity index (CCI). Bacteremias were categorized as community acquired, healthcare associated (HCA), and hospital acquired. We defined multiple subgroups by combining the following characteristics: species, acquisition, age group, gender, CCI level, and location of infection. Assuming a sinusoidal model, seasonal variation was assessed by the peak-to-trough (PTT) ratio with a 95% confidence interval (CI). RESULTS In total, we included 16,006 E. coli, 6,924 S. aureus, and 4,884 S. pneumoniae bacteremia cases. For E. coli, the seasonal variation was highest for community-acquired cases (PTT ratio, 1.24; 95% CI, 1.17-1.32), was diminished for HCA (PTT ratio, 1.14; 95% CI, 1.04-1.25), and was missing for hospital-acquired cases. No seasonal variation was observed for S. aureus. S. pneumoniae showed high seasonal variation, which did not differ according to acquisition (overall PTT ratio, 3.42; 95% CI, 3.10-3.83). CONCLUSIONS Seasonal variation was mainly related to the species although the place of acquisition was important for E. coli. Infect Control Hosp Epidemiol 2016;37:946-953. PMID:27142942

  3. Antimicrobial activity of Hibiscus sabdariffa aqueous extracts against Escherichia coli O157:H7 and Staphylococcus aureus in a microbiological medium and milk of various fat concentrations.

    Science.gov (United States)

    Higginbotham, Kristen L; Burris, Kellie P; Zivanovic, Svetlana; Davidson, P Michael; Stewart, C Neal

    2014-02-01

    Hibiscus sabdariffa L. calyces are widely used in the preparation of beverages. The calyces contain compounds that exhibit antimicrobial activity, yet little research has been conducted on their possible use in food systems as antimicrobials. Aqueous extracts prepared from the brand "Mi Costenita" were sterilized by membrane filtration (0.22-μm pore size) or autoclaving (121 °C, 30 min) and tested for antimicrobial activity against the foodborne pathogens Escherichia coli O157:H7 strains ATCC 43894 and Cider and Staphylococcus aureus strains SA113 and ATCC 27708 in a microbiological medium and ultrahigh-temperature-processed milk with various fat percentages. Extracts heated by autoclaving exhibited greater activity than did filtered extracts in a microbiological medium. Against E. coli, results of 20 mg/ml filtered extract were not different from those of the control, whereas autoclaved extracts reduced viable cells ca. 3 to 4 log CFU/ml. At 60 mg/ml, both extracts inactivated cells after 24 h. There were reduced populations of both strains of S. aureus (ca. 2.7 and 3 log CFU/ml, respectively) after 24 h of incubation in 40 mg/ml filtered extracts. When grown in autoclaved extracts at 40 mg/ml, both strains of S. aureus were inactivated after 9 h. Autoclaved extracts had decreased anthocyanin content (2.63 mg/liter) compared with filtered extracts (14.27 mg/liter), whereas the phenolic content (48.7 and 53.8 mg/g) remained similar for both treatments. Autoclaved extracts were then tested for activity in milk at various fat concentrations (skim [3.25%]) against a 1:1 mixture of the two strains of E. coli O157:H7 and a 1:1 mixture of the two strains of S. aureus. Extracts at 40 mg/ml inactivated S. aureus after 168 h in skim and whole milk, and E. coli was inactivated after 96 h in 60 mg/ml extract in all fat levels. These findings show the potential use of Hibiscus extracts to prevent the growth of pathogens in foods and beverages. PMID:24490920

  4. A multiplex RTi-PCR reaction for simultaneous detection of Escherichia coli O157:H7, Salmonella spp. and Staphylococcus aureus on fresh, minimally processed vegetables.

    Science.gov (United States)

    Elizaquível, Patricia; Aznar, Rosa

    2008-08-01

    In this work, a new multiplex single-tube real-time PCR approach is presented for the detection of Escherichia coli O157:H7, Salmonella spp. and Staphylococcus aureus, three of the more frequent food-borne bacterial pathogens that are usually investigated in a variety of food matrices. The study includes the design and specificity testing, of a new primer and probe specific for Salmonella spp. Reaction conditions were adjusted for the simultaneous amplification and detection of specific fragments in the beta-glucuronidase (uidA, E. coli) and Thermonulease (nuc, Sta. aureus) genes, and in the replication origin sequence (oriC, Salmonella spp.). Melting-curve analysis using a SYBR Green I RTi-PCR approach showed characteristic T(m) values demonstrating the specific and efficient amplification of the three fragments. Subsequently, a TaqMan RTi-PCR approach was settled, using FAM, NED and VIC fluorescently labelled specific probes for an automated detection. It was equally sensitive than uniplex RTi-PCR reactions in Sta. aureus and E. coli O157:H7, using same amounts of purified DNA, and allowed detection of 10 genome equivalents in the presence of 10(2) or 10(4) genome equivalents of the other two pathogens. Finally, it was tested in artificially inoculated fresh, minimally processed vegetables, revealing a sensitivity of 10(3)CFUg(-1) each of these pathogens in direct detection, following DNA extraction with DNeasy Tissue Kit (Qiagen). The multiplex RTi-PCR developed scored the sensitivity recognised for PCR in food and it allows a high-throughput and automation, thus it is promising as a rapid and cost-effective test for the food industry. PMID:18541170

  5. Uji Antibakteri Ekstak Daun Sirsak (Annonamuricata Linn) terhadap Bakteri Escherichia coli dan Staphylococcusaureus

    OpenAIRE

    Pradikta, Rina

    2015-01-01

    Antibacterial activity of methanol extract soursop leaf (Annona muricata Linn) toEscherichia coli, and Staphylococcus aureus with diffusionmethod has been done. Result showed soursop leaf methanol extract (Annona muricata Linn) has activity as antibacterial. at concentration of 10 % to Escherichia coli and Staphylococcus aureus with resistancediameter of 10 mm to Escherichia coli, and 8,52 mm to Staphylococcus aureus each. While in the water solvent resistent diameter for bacteria Escherichia...

  6. Antibacterial activity of defensin PaDef from avocado fruit (Persea americana var. drymifolia) expressed in endothelial cells against Escherichia coli and Staphylococcus aureus.

    Science.gov (United States)

    Guzmán-Rodríguez, Jaquelina Julia; López-Gómez, Rodolfo; Suárez-Rodríguez, Luis M; Salgado-Garciglia, Rafael; Rodríguez-Zapata, Luis C; Ochoa-Zarzosa, Alejandra; López-Meza, Joel E

    2013-01-01

    Antimicrobial therapy is a useful tool to control infectious diseases in general and rising antibiotic resistant microorganisms in particular. Alternative strategies are desirable, and antimicrobial peptides (AMP) represent attractive control agents. Mexican avocado (Persea americana var. drymifolia) is used in traditional medicine; however, the AMP production has not been reported in this plant. We obtained a cDNA library from avocado fruit and clone PaDef was identified, which has a cDNA (249 bp) encoding a protein (78 aa) homologous with plant defensins (>80%). We expressed the defensin PaDef cDNA (pBME3) in the bovine endothelial cell line BVE-E6E7. Polyclonal and clonal populations were obtained and their activity was evaluated against Escherichia coli, Staphylococcus aureus, and Candida albicans. E. coli viability was inhibited with 100 μg/mL of total protein from clones (>55%). Also, S. aureus viability was inhibited from 50 μg/mL total protein (27-38%) but was more evident at 100 μg/mL (52-65%). This inhibition was higher than the effect showed by polyclonal population (~23%). Finally, we did not detect activity against C. albicans. These results are the first report that shows antimicrobial activity of a defensin produced by avocado and suggest that this AMP could be used in the control of pathogens. PMID:24319695

  7. Antibacterial Activity of Defensin PaDef from Avocado Fruit (Persea americana var. drymifolia Expressed in Endothelial Cells against Escherichia coli and Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Jaquelina Julia Guzmán-Rodríguez

    2013-01-01

    Full Text Available Antimicrobial therapy is a useful tool to control infectious diseases in general and rising antibiotic resistant microorganisms in particular. Alternative strategies are desirable, and antimicrobial peptides (AMP represent attractive control agents. Mexican avocado (Persea americana var. drymifolia is used in traditional medicine; however, the AMP production has not been reported in this plant. We obtained a cDNA library from avocado fruit and clone PaDef was identified, which has a cDNA (249 bp encoding a protein (78 aa homologous with plant defensins (>80%. We expressed the defensin PaDef cDNA (pBME3 in the bovine endothelial cell line BVE-E6E7. Polyclonal and clonal populations were obtained and their activity was evaluated against Escherichia coli, Staphylococcus aureus, and Candida albicans. E. coli viability was inhibited with 100 μg/mL of total protein from clones (>55%. Also, S. aureus viability was inhibited from 50 μg/mL total protein (27–38% but was more evident at 100 μg/mL (52–65%. This inhibition was higher than the effect showed by polyclonal population (~23%. Finally, we did not detect activity against C. albicans. These results are the first report that shows antimicrobial activity of a defensin produced by avocado and suggest that this AMP could be used in the control of pathogens.

  8. Caracterização química e efeito inibitório de óleos essenciais sobre o crescimento de Staphylococcus aureus e Escherichia coli Chemical ckaracterization and inhibitory effect of essential oils on the growth of Staphylococcus aureus and Escherichia coli

    OpenAIRE

    Alcilene de Abreu Pereira; Maria das Graças Cardoso; Luiz Ronaldo de Abreu; Augusto Ramalho de Morais; Luiz Gustavo Lima Guimarães; Ana Paula Soares Pinto Salgado

    2008-01-01

    Objetivou-se avaliar o efeito inibitório dos óleos essenciais de Cymbopogon citratus (capim-limão), Origanum vulgare (orégano) e Syzygium aromaticum (cravo-da-índia); os experimentos foram realizados com as bactérias Staphylococcus aureus e Escherichia coli, importantes patógenos causadores de contaminações em queijos e outros alimentos. Para quantificação e identificação dos constituintes químicos dos óleos, utilizou-se um cromatógrafo gasoso acoplado a um espectrômetro de massa. Os resultad...

  9. Inhibitory effect of pomegranate (Punica granatum L.) polyphenol extracts on the bacterial growth and survival of clinical isolates of pathogenic Staphylococcus aureus and Escherichia coli.

    Science.gov (United States)

    Pagliarulo, Caterina; De Vito, Valentina; Picariello, Gianluca; Colicchio, Roberta; Pastore, Gabiria; Salvatore, Paola; Volpe, Maria Grazia

    2016-01-01

    In the present study major polyphenols of pomegranate arils and peel by-products were extracted in 50% (v/v) aqueous ethanol, characterized and used in microbiological assays in order to test antimicrobial activity against clinically isolated human pathogenic microorganisms. Total concentration of polyphenols and in vitro antioxidant properties were determined by the Folin-Ciocalteu and DPPH methods, respectively. The most abundant bioactive molecules, including anthocyanins, catechins, tannins, gallic and ellagic acids were identified by RP-HPLC-DAD, also coupled to off-line matrix assisted laser desorption/ionization (MALDI-TOF) mass spectrometry (MS). The inhibitory spectrum of extracts against test microorganisms was assessed by the agar well-diffusion method. Data herein indicated that both pomegranate aril and peel extracts have an effective antimicrobial activity, as evidenced by the inhibitory effect on the bacterial growth of two important human pathogens, including Staphylococcus aureus and Escherichia coli, which are often involved in foodborne illness. PMID:26213044

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

    Science.gov (United States)

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

    2015-12-01

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

  11. Atividade antibacteriana de óleos essenciais de plantas frente a linhagens de Staphylococcus aureus e Escherichia coli isoladas de casos clínicos humanos Antibacterial activity of plant essential oils against Staphylococcus aureus and Escherichia coli strains isolated from human specimens

    Directory of Open Access Journals (Sweden)

    M.T.N. Silva

    2009-01-01

    Full Text Available A ação antibacteriana in vitro de óleos essenciais de seis plantas foi verificada por meio da Concentração Inibitória Mínima (CIM=%v/v pela diluição dos óleos em meio de cultura Mueller Hinton Agar, frente a linhagens de Staphylococcus aureus (n=16 e Escherichia coli (n=16 isoladas de casos clínicos humanos, além de 1 amostra padrão ATCC para cada espécie (Sa ATCC 25923 e Ec ATCC 25922, e determinação de curvas de sobrevivência em concentrações equivalentes a CIM90% dos respectivos óleos. O óleo essencial de canela foi o mais eficiente, com valores de CIM90% de 0,047 e 0,09 para S. aureus e E. coli respectivamente, enquanto gengibre (0,09, cravo da índia (0,095 e capim cidreira (0,1 apresentaram eficiências semelhantes para S. aureus. Frente a E. coli, os óleos de gengibre (0,52 e capim cidreira (0,55 foram equivalentes quanto à eficiência. De acordo com as curvas de sobrevivência, foi possível verificar também que os valores de CIM90% obtidos podem ser tanto bactericidas ou bacteriostáticas de acordo com a bactéria testada. Em conclusão, verificou-se que os óleos essenciais testados foram efetivos no controle do desenvolvimento bacteriano, sendo o potencial antimicrobiano diferente em função da espécie bacteriana testada, sendo que a bactéria Gram positiva (S. aureus mostrou-se mais susceptível aos óleos testados que a Gram negativa (E. coli.The in vitro antibacterial activity of essential oils from six plants was verified through minimal inhibitory concentration (MIC=%v/v, determined by diluting the oils in culture medium Mueller Hinton Agar, against Staphylococcus aureus (n=16 and Escherichia coli (n=16 strains isolated from human clinical specimens, besides one standard ATCC strain for each species (Sa 25923 and Ec 25922. Time-kill curves were also determined at concentrations equivalent to MIC90% for the respective oils. Cinnamon oil was the most efficient, with MIC90% values of 0.047 and 0.09 against

  12. X-ray absorption near-edge structure (XANES) spectroscopy study of the interaction of silver ions with Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli.

    Science.gov (United States)

    Bovenkamp, Gudrun Lisa; Zanzen, Ulrike; Krishna, Katla Sai; Hormes, Josef; Prange, Alexander

    2013-10-01

    Silver ions are widely used as antibacterial agents, but the basic molecular mechanism of this effect is still poorly understood. X-ray absorption near-edge structure (XANES) spectroscopy at the Ag LIII, S K, and P K edges reveals the chemical forms of silver in Staphylococcus aureus and Escherichia coli (Ag(+) treated). The Ag LIII-edge XANES spectra of the bacteria are all slightly different and very different from the spectra of silver ions (silver nitrate and silver acetate), which confirms that a reaction occurs. Death or inactivation of bacteria was observed by plate counting and light microscopy. Silver bonding to sulfhydryl groups (Ag-S) in cysteine and Ag-N or Ag-O bonding in histidine, alanine, and DL-aspartic acid was detected by using synthesized silver-amino acids. Significantly lower silver-cysteine content, coupled with higher silver-histidine content, in Gram-positive S. aureus and Listeria monocytogenes cells indicates that the peptidoglycan multilayer could be buffering the biocidal effect of silver on Gram-positive bacteria, at least in part. Bonding of silver to phosphate groups was not detected. Interaction with DNA or proteins can occur through Ag-N bonding. The formation of silver-cysteine can be confirmed for both bacterial cell types, which supports the hypothesis that enzyme-catalyzed reactions and the electron transport chain within the cell are disrupted. PMID:23934494

  13. Caracterização química e efeito inibitório de óleos essenciais sobre o crescimento de Staphylococcus aureus e Escherichia coli Chemical ckaracterization and inhibitory effect of essential oils on the growth of Staphylococcus aureus and Escherichia coli

    Directory of Open Access Journals (Sweden)

    Alcilene de Abreu Pereira

    2008-06-01

    Full Text Available Objetivou-se avaliar o efeito inibitório dos óleos essenciais de Cymbopogon citratus (capim-limão, Origanum vulgare (orégano e Syzygium aromaticum (cravo-da-índia; os experimentos foram realizados com as bactérias Staphylococcus aureus e Escherichia coli, importantes patógenos causadores de contaminações em queijos e outros alimentos. Para quantificação e identificação dos constituintes químicos dos óleos, utilizou-se um cromatógrafo gasoso acoplado a um espectrômetro de massa. Os resultados dos testes in vitro, os óleos essenciais de C. citratus, O. vulgare e S. aromaticum promoveram efeito inibitório sobre as bactérias S. aureus e E. coli, porém o S. aromaticum apresentou melhor formação de halo de inibição nas menores concentrações. Para o efeito sinergístico dos óleos sobre as bactérias não foram observadas diferenças quando comparados com o efeito individual dos mesmos. Foi possível verificar que os óleos possuem efeito inibitório sobre os microrganismos estudados, sendo, portanto uma alternativa no controle microbiológico de alimentos.With the aim of evaluating the inhinibitory effect of the Cymbopogon citratus (lemon grass, Origanun vulgare (oregano and Syzygium aromaticum (clove, experiments were performed in laboratories, with the Staphylococcus aureus, Escherichia coli bacteria, important pathogenics which contaminate cheese and other foods. For the oil chemical constitutions quantification and identification, the gas chromatography attached mass spectrometry to a was used. In the results in vitro test, the C. citratus, O. vulgare and S. aromaticum essential oils presented antimicrobian activity over S. aureus and E. coli bacteria, however, S. aromaticum presented better formation of inhibition halo in smaller concentrations. For the oil synergetic effect over bacteria and fungi, no significant difference was noticed when compared to their own individual effect. It was possible to verify that the

  14. Minimum inhibitory (MIC and minimum microbicidal concentration (MMC of polihexanide and triclosan against antibiotic sensitive and resistant Staphylococcus aureus and Escherichia coli strains

    Directory of Open Access Journals (Sweden)

    Assadian, Ojan

    2011-01-01

    Full Text Available Background: An in-vitro study was conducted investigating the antimicrobial efficacy of polihexanide and triclosan against clinical isolates and reference laboratory strains of Staphylococcus aureus and Escherichia coli. Methods: The minimal inhibitory concentration (MIC and the minimal microbicidal concentration (MMC were determined following DIN 58940-81 using a micro-dilution assay and a quantitative suspension test following EN 1040. Polihexanide was tested in polyethylene glycol 4000, triclosan in aqueous solutions. Results: Against all tested strains the MIC of polihexanide ranged between 1–2 µg/mL. For triclosan the MICs varied depending on strains ranging between 0.5 µg/mL for the reference strains and 64 µg/mL for two clinical isolates. A logRF >5 without and logRF >3 with 0.2% albumin burden was achieved at 0.6 µg/mL triclosan. One exception was S. aureus strain H-5-24, where a triclosan concentration of 0.6 µg/mL required 1 minute without and 10 minutes with albumin burden to achieve the same logRFs. Polihexanide achieved a logRF >5 without and logRF >3 with albumin burden at a concentration of 0.6 µg/mL within 30 sec. The exception was the North-German epidemic MRSA strain, were an application time of 5 minutes was required. Conclusion: The clinical isolates of E. coli generally showed higher MICs against triclosan, both in the micro-dilution assay as well in the quantitative suspension test than comparable reference laboratory strains. For polihexanide and triclosan strain dependant susceptibility was shown. However, both antimicrobial compounds are effective when used in concentrations common in practice.

  15. Recurrent Escherichia coli bacteremia.

    Science.gov (United States)

    Maslow, J N; Mulligan, M E; Arbeit, R D

    1994-01-01

    Escherichia coli is the most common gram-negative organism associated with bacteremia. While recurrent E. coli urinary tract infections are well-described, recurrent E. coli bacteremia appears to be uncommon, with no episodes noted in multiple series of patients with gram-negative bacteremias. We report on 5 patients with recurrent bloodstream infections identified from a series of 163 patients with E. coli bacteremia. For each patient, the isolates from each episode were analyzed by pulsed-field gel electrophoresis (PFGE) and ribotyping and for the presence of E. coli virulence factors. For each of four patients, the index and recurrent episodes of bacteremia represented the same strain as defined by PFGE, and the strains were found to carry one or more virulence factors. The remaining patient, with two episodes of bloodstream infection separated by a 4-year interval, was infected with two isolates that did not carry any virulence factors and that were clonally related by ribotype analysis but differed by PFGE. All five patients had either a local host defense defect (three patients) or impaired systemic defenses (one patient) or both (one patient). Thus, recurrent E. coli bacteremia is likely to represent a multifactorial process that occurs in patients with impaired host defenses who are infected with virulent isolates. Images PMID:7910828

  16. Sinergismo entre óleos essenciais e drogas antimicrobianas sobre linhagens de Staphylococcus aureus e Escherichia coli isoladas de casos clínicos humanos Synergism between essential oils and antimicrobial drugs against Staphylooccus aureus and Escherichia coli strains from human infections

    Directory of Open Access Journals (Sweden)

    Juliana A. A. Zago

    2009-12-01

    Full Text Available Estudos com plantas e utilização em terapias combinatórias têm sido estimulados. Verificou-se as possíveis interações entre óleos essenciais de plantas [canela (Cinnamomum zeylanicum Blume Lauraceae, capim-cidreira (Cymbopogon citratus (DC. Stapf, Poaceae, hortelã-pimenta (Mentha piperita L. Lamiaceae, gengibre (Zingiber officinale Roscoe Zingiberaceae, cravo-da-índia (Caryophillus aromaticus L. Myrtaceae e alecrim (Rosmarinus officinalis L. Lamiaceae] combinados a oito drogas antimicrobianas frente a doze linhagens de Staphylococcus aureus e doze de Escherichia coli isoladas de humanos. Após determinação da Concentração Inibitória Mínima (CIM para os óleos pelo método da diluição foram realizados ensaios para verificação de sinergismo entre os óleos essenciais e os antimicrobianos pela metodologia de Kirby & Bauer. S. aureus foi mais suscetível às interações óleos e drogas, tendo o óleo de capim cidreira apresentado sinergismo com as oito drogas testadas, seguido pelo óleo de hortelã com sete drogas. Nos ensaios com E. coli, houve sinergismo apenas para os óleos de alecrim (três drogas e capim-cidreira (duas drogas. Não ocorreram casos de antagonismo e os resultados de sinergismo foram influenciados pelos microrganismos estudados.The studies with plants and combinatory therapy have been stimulated. The interactions between cinnamon (Cinnamomun zeylanicum Blume Lauraceae, lemon grass (Cymbopogon citratus (DC. Stapf, Poaceae, mint (Mentha piperita L. Lamiaceae, ginger (Zingiber officinale Roscoe Zingiberaceae, clove (Caryophillus aromaticus L. Myrtaceae and rosemary (Rosmarinus officinalis L. Lamiaceae and eight antimicrobial drug was carried. It was made against twelve S. aureus and twelve E.coli strains isolated from human specimens. After minimal inhibitory concentration (MIC values determination of essential oils by dilution agar method, the synergism assays were performed by Kirby and Bauer method. The S

  17. Inativação termoquímica de Escherichia coli, Staphylococcus aureus e Salmonella enterica Enteritidis por óleos essenciais

    Directory of Open Access Journals (Sweden)

    Alcilene de Abreu Pereira

    2014-11-01

    Full Text Available O controle do crescimento microbiano tanto na indústria de alimentos quanto em ambientes hospitalares é de extrema importância. Entretanto, observa-se aumento da resistência dos microrganismos aos desinfetantes mais empregados, observando-se a necessidade de estudos com novos antimicrobianos. Assim, o objetivo desse trabalho foi avaliar a atividade antimicrobiana e a curva de morte termoquímica de soluções desinfetantes de óleos essenciais sobre Escherichia coli, Staphylococcus aureus e Salmonella Enteritidis. Foram utilizados os óleos essenciais de Thymus vulgaris (tomilho, Elettaria cardamomum (cardamomo, Eugenia caryophyllus (cravo botão e Foeniculum vulgare dulce (funcho doce. As concentrações mínimas inibitórias foram determinadas utilizando-se a técnica de diluição em placas. As concentrações testadas foram de (%: 0,00; 0,25; 0,5; 1,0; 2,0; 2,5; 3,0; 3,5; 4,0; 4,5; e 5,0. Escherichia coli foi a única bactéria sensível a todos os óleos em concentrações abaixo de 5%. Cravo da índia não inibiu o crescimento de S. aureus nas concentrações testadas. Somente o óleo essencial de tomilho inibiu o crescimento de Salmonella Enteritidis. Observando-se as curvas de morte termoquímica de S. aureus, nota-se que a solução desinfetante contendo óleo essencial de tomilho foi a mais eficiente, tanto a 25 quanto a 40°C, sendo necessário apenas 10min. de contato para não serem mais detectadas células viáveis. A solução desinfetante contendo 0,25% de óleo essencial de tomilho, tanto a 25 quanto a 40°C, eliminou as células de S. Enteritidis após10min. de contato. Já pra E. coli , os melhores resultados foram obtidos com as soluções desinfetantes contendo óleos essenciais de funcho doce e cravo da índia a 25 e 40°C e tomilho a 40°C. Todos os tratamentos, exceto aqueles contendo óleo essencial de cardamomo, reduziram o número de células viáveis das bactérias testadas em pelo menos 5 ciclos log, sendo

  18. Atividade antibacteriana de óleos essenciais de plantas frente a linhagens de Staphylococcus aureus e Escherichia coli isoladas de casos clínicos humanos Antibacterial activity of plant essential oils against Staphylococcus aureus and Escherichia coli strains isolated from human specimens

    OpenAIRE

    M.T.N. Silva; P.I. Ushimaru; L.N. Barbosa; M.L.R.S. Cunha; A. Fernandes Junior

    2009-01-01

    A ação antibacteriana in vitro de óleos essenciais de seis plantas foi verificada por meio da Concentração Inibitória Mínima (CIM=%v/v) pela diluição dos óleos em meio de cultura Mueller Hinton Agar, frente a linhagens de Staphylococcus aureus (n=16) e Escherichia coli (n=16) isoladas de casos clínicos humanos, além de 1 amostra padrão ATCC para cada espécie (Sa ATCC 25923 e Ec ATCC 25922), e determinação de curvas de sobrevivência em concentrações equivalentes a CIM90% dos respectivos óleos....

  19. [Determination of the antimicrobial capacity of green tea (Camellia sinensis) against the potentially pathogenic microorganisms Escherichia coli, Salmonella enterica, Staphylococcus aureus, Listeria monocytogenes, Candida albicans and Aspergillus niger].

    Science.gov (United States)

    Mora, Andreína; Pawa, Jonathan; Chaverri, José M; Arias, María Laura

    2013-09-01

    Many studies can be found in scientific literature demonstrating the antimicrobial capacity of different herbs, including green tea. Never-theless, many results are divergent or cannot be compared. Several green tea formulations may be found in market, but there is scarce or non-information about its activity. In this work, the potential antimicrobial effect of 50 samples of dry green tea and in 10% infusion against Escherichia coli, Salmonella enterica, Listeria monocytogenes, Staphylococcus aureus, Candida albicans and Aspergillus niger distributed in the metropolitan area of Costa Rica, was determined. This activity was compared with the effect produced by Chinese origin green tea (Camellia sinensis). Different solvents were evaluated for preparing polyphenol enriched extracts from green tea samples. Total phenols were determined using the Folin-Ciocalteu spectrophotometric methodology, using galic acid as reference. Antimicrobial activity of green tea extracts and infusions was evaluated using the microplate methodology described by Breuking (2006). Ethanol was the most efficient solvent used for the polyphenol extractions. There was no antimicrobial effect of the different green tea extracts and infusions against the microorganisms evaluated, except for Listeria monocytogenes, where the extracts of 70% of samples analyzed and the control showed an inhibitory effect in the 10.5 mg/mL and 1.05 mg/L concentrations. None of the infusions tested, including the control, showed any effect against this bacteria. PMID:25362825

  20. Simultaneous Detection of Listeria monocytogenes, Escherichia coli O157:H7, Bacillus cereus, Salmonella spp., and Staphylococcus aureus in Low-fatted Milk by Multiplex PCR

    Science.gov (United States)

    Kim, Ji-Hyun; Rhim, Seong-Ryul; Kim, Kee-Tae; Paik, Hyun-Dong

    2014-01-01

    A rapid and specific PCR assay for the simultaneous detection of Listeria monocytogenes, Escherichia coli O157:H7, Bacillus cereus, Salmonella spp., and Staphylococcus aureus in foods was developed to reduce the detection time and to increase sensitivity. Multiplex PCR developed in this study produced only actA, fliC, hbl, invA, ileS amplicons, but did not produce any non-specific amplicon. The primer sets successfully amplified the target genes in the multiplex PCR without any non-specific or additional bands on the other strains. The multiplex PCR assays also amplified some target genes from five pathogens, and multiplex amplification was obtained from as little as 1 pg of DNA. According to the results from the sensitivity evaluation, the multiplex PCR developed in this study detected 10 cells/mL of the pathogens inoculated in milk samples, respectively. The results suggested that multiplex PCR was an effective assay demonstrating high specificity for the simultaneous detection of five target pathogens in food system. PMID:26761507

  1. Growth of Listeria monocytogenes, Salmonella spp., Escherichia coli O157:H7, and Staphylococcus aureus on cheese during extended storage at 25°C.

    Science.gov (United States)

    Leong, Wan Mei; Geier, Renae; Engstrom, Sarah; Ingham, Steve; Ingham, Barbara; Smukowski, Marianne

    2014-08-01

    Potentially hazardous foods require time/temperature control for safety. According to the U.S. Food and Drug Administration Food Code, most cheeses are potentially hazardous foods based on pH and water activity, and a product assessment is required to evaluate safety of storage >6 h at 21°C. We tested the ability of 67 market cheeses to support growth of Listeria monocytogenes (LM), Salmonella spp. (SALM), Escherichia coli O157:H7 (EC), and Staphylococcus aureus (SA) over 15 days at 25°C. Hard (Asiago and Cheddar), semi-hard (Colby and Havarti), and soft cheeses (mozzarella and Mexican-style), and reduced-sodium or reduced-fat types were tested. Single-pathogen cocktails were prepared and individually inoculated onto cheese slices (∼10(5) CFU/g). Cocktails were 10 strains of L. monocytogenes, 6 of Salmonella spp., or 5 of E. coli O157:H7 or S. aureus. Inoculated slices were vacuum packaged and stored at 25°C for ≤ 15 days, with surviving inocula enumerated every 3 days. Percent salt-in-the-moisture phase, percent titratable acidity, pH, water activity, and levels of indigenous/starter bacteria were measured. Pathogens did not grow on 53 cheeses, while 14 cheeses supported growth of SA, 6 of SALM, 4 of LM, and 3 of EC. Of the cheeses supporting pathogen growth, all supported growth of SA, ranging from 0.57 to 3.08 log CFU/g (average 1.70 log CFU/g). Growth of SALM, LM, and EC ranged from 1.01 to 3.02 log CFU/g (average 2.05 log CFU/g), 0.60 to 2.68 log CFU/g (average 1.60 log CFU/g), and 0.41 to 2.90 log CFU/g (average 1.69 log CFU/g), respectively. Pathogen growth varied within cheese types or lots. Pathogen growth was influenced by pH and percent salt-in-the-moisture phase, and these two factors were used to establish growth/no-growth boundary conditions for safe, extended storage (≤25°C) of pasteurized milk cheeses. Pathogen growth/no-growth could not be predicted for Swiss-style cheeses, mold-ripened or bacterial surface-ripened cheeses, and cheeses

  2. Zinc ascorbate has superoxide dismutase-like activity and in vitro antimicrobial activity against Staphylococcus aureus and Escherichia coli

    OpenAIRE

    Iinuma K; Tsuboi I

    2012-01-01

    Katsuhiro Iinuma, Isami TsuboiBML General Laboratory, Kawagoe, Saitama, JapanBackground: Acne vulgaris is a common dermatological disease, and its pathogenesis is multifactorial.Objective: We examined whether the ascorbic acid derivative zinc ascorbate has superoxide dismutase (SOD)-like activity. SOD is an enzyme that controls reactive oxygen species production. In addition, the in vitro antimicrobial activity of zinc ascorbate against the Gram-positive bacterium Staphylococcus aureus and th...

  3. 马鞭草提取液对大肠杆菌和金黄色葡萄球菌生长的影响%Influence of Verbena officinalis on the Growth of Escherichia coli and Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    赵锦慧; 赖颖; 葛红莲; 郭婕

    2012-01-01

    为研究马鞭草(Verbena officinalis L.)提取液对大肠杆菌(Escherichia coli)和金黄色葡萄球菌(Staphylococcus aureus)的抑制作用,将菌悬液与不同浓度马鞭草提取液混合均匀涂布到细菌培养基上进行生物学测定.结果表明,马鞭草提取液能抑制2种细菌,对大肠杆菌和金黄色葡萄球菌的最小抑菌浓度(MIC)分别为500.0 mg/mL和250.0 mg/mL;药液浓度分别不低于500.0 mg/mL和250.0 mg/mL时,马鞭草提取液对大肠杆菌和金黄色葡萄球菌的抑菌率均为100.00%.%The bacteria liquid with 103CFU/mL was prepared by flat calculating colony, the mixture of bacteria liquid and Verbena officinalis L, with different concentrations were smeared on normal bacteria culture medium, the influence of V. Officinalis on the growth of Escherichia coli and Staphylococcus aureus was researched. The results showed that growth of E. Coli and S. Aureus was significantly inhibited by V. Officinalis, the MIC of V. Officinalis to E. Coli and S. Aureus was 500.0 mg/mL and 250.0mg/mL separately; the inhibitory rate was 100.00% under MIC.

  4. Escherichia coli Uropathogenesis In Vitro

    DEFF Research Database (Denmark)

    Andersen, Thomas E; Khandige, Surabhi; Madelung, Michelle;

    2012-01-01

    Uropathogenic Escherichia coli (UPEC) strains are capable of invading bladder epithelial cells (BECs) on the bladder luminal surface. Based primarily on studies in mouse models, invasion is proposed to trigger an intracellular uropathogenic cascade involving intracellular bacterial proliferation...

  5. Bactericidal activities of health-promoting,food-derived powders against the foodborne pathogens Escherichia coli,listeria monocytogenes, salmonella enterica,and staphylococcus aureus

    Science.gov (United States)

    We evaluated the relative bactericidal activities of 10 presumed health-promoting food-based powders (nutraceuticals) and for comparison, several selected known components of such powders against the following foodborne pathogens: Escherichia coli O157:H7, Salmonella enterica, Listeria monocytogenes...

  6. Minimum inhibitory (MIC) and minimum microbicidal concentration (MMC) of polihexanide and triclosan against antibiotic sensitive and resistant Staphylococcus aureus and Escherichia coli strains

    OpenAIRE

    Assadian, Ojan; Wehse, Katrin; Hübner, Nils-Olaf; Koburger, Torsten; Bagel, Simone; Jethon, Frank; Kramer, Axel

    2011-01-01

    Background: An in-vitro study was conducted investigating the antimicrobial efficacy of polihexanide and triclosan against clinical isolates and reference laboratory strains of Staphylococcus aureus and E scherich ia coli. Methods: The minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC) were determined following DIN 58940-81 using a micro-dilution assay and a quantitative suspension test following EN 1040. Polihexanide was tested in polyethylene glycol 4000...

  7. Mortality and hospital stay associated with resistant Staphylococcus aureus and Escherichia coli bacteremia: estimating the burden of antibiotic resistance in Europe.

    Directory of Open Access Journals (Sweden)

    Marlieke E A de Kraker

    2011-10-01

    Full Text Available BACKGROUND: The relative importance of human diseases is conventionally assessed by cause-specific mortality, morbidity, and economic impact. Current estimates for infections caused by antibiotic-resistant bacteria are not sufficiently supported by quantitative empirical data. This study determined the excess number of deaths, bed-days, and hospital costs associated with blood stream infections (BSIs caused by methicillin-resistant Staphylococcus aureus (MRSA and third-generation cephalosporin-resistant Escherichia coli (G3CREC in 31 countries that participated in the European Antimicrobial Resistance Surveillance System (EARSS. METHODS AND FINDINGS: The number of BSIs caused by MRSA and G3CREC was extrapolated from EARSS prevalence data and national health care statistics. Prospective cohort studies, carried out in hospitals participating in EARSS in 2007, provided the parameters for estimating the excess 30-d mortality and hospital stay associated with BSIs caused by either MRSA or G3CREC. Hospital expenditure was derived from a publicly available cost model. Trends established by EARSS were used to determine the trajectories for MRSA and G3CREC prevalence until 2015. In 2007, 27,711 episodes of MRSA BSIs were associated with 5,503 excess deaths and 255,683 excess hospital days in the participating countries, whereas 15,183 episodes of G3CREC BSIs were associated with 2,712 excess deaths and 120,065 extra hospital days. The total costs attributable to excess hospital stays for MRSA and G3CREC BSIs were 44.0 and 18.1 million Euros (63.1 and 29.7 million international dollars, respectively. Based on prevailing trends, the number of BSIs caused by G3CREC is likely to rapidly increase, outnumbering the number of MRSA BSIs in the near future. CONCLUSIONS: Excess mortality associated with BSIs caused by MRSA and G3CREC is significant, and the prolongation of hospital stay imposes a considerable burden on health care systems. A foreseeable shift in

  8. Nano Polyamidoamine-G7 (NPAMAM-G7 Dendrimer Synthesis and Assessment the Effect of its antibacterial on Escherichia Coli, Klebsiella Oxytoca, Pseudomonas Aeruginosa , Proteus Mirabilis and Staphylococcus Aureus from aqueous solution

    Directory of Open Access Journals (Sweden)

    mitra Gholami

    2016-06-01

    Full Text Available Background: Nano scale dendrimers are macromolecules synthetic which frequently used in medical and health field. This study was aimed to examine synthesis and the antibacterial effect of NanoPolyamidoamine-G7 (NPAMAM-G7 dendrimer on Escherichia Coli, Klebsiella Oxytoca, Pseudomonas Aeruginosa , Proteus Mirabilis and Staphylococcus Aureus from aqueous solution. Material and methods: In this experimental study, initially dilution of 103 CFU/ml were prepared from each strain of bacteria. Then different concentrations of dendrimer (0.025, 0.25, 2.5 and 25 µg/ml in the laboratory temperature (23-25 °C was added to water. In order to determine the efficiency of dendrimers in removal of bacteria, samples were taken at different times (0, 10, 20, 30, 40, 50 and 60 min and were cultured on nutrient agar medium. Samples were incubated for 24 hours at 37 °C and then number of colonies were counted. Results: Antibacterial properties of dendrimers in aqueous solution by increasing the dendrimer concentration and contact time is directly related. At a concentration of 25 μg/ml at 60 minutes all bacteria except Staphylococcus Aureus, and at 30 minutes, Escherichia Coli and Klebsiella Oxytoca bacteria for 100% excluded. The concentration of 2.5 μg/ml at 60 minutes of bacteria, Escherichia Coli, Klebsiella Oxytoca and Proteus Mirabilis are 100% excluded. All concentrations of dendrimers at different times were reduced bacteria in the PAMAM- G7 dendrimer effect on gram-negative bacteria, gram-positive bacteria was better. Conclusion: The NPAMAM-G7 dendrimer with end amine groups exhibited a positive impact on the removal of standard strains, gram-positive and gram-negative bacteria. Therefore, it is possible to use these nanodendrimers as antibacterial in the future.

  9. Total flavonoid and phenolic contents of n-butanol extract of Samanea saman leaf and the antibacterial activity towards Escherichia coli and Staphylococcus aureus

    Science.gov (United States)

    Rita, Wiwik Susanah; Swantara, I. Made Dira; Asih, I. A. Raka Astiti; Sinarsih, Ni Ketut; Suteja, I. Kadek Pater

    2016-03-01

    Total flavonoid and phenolic contents in some natural products was suspected of having a positive correlation to its activity in inhibiting the growth of bacteria. The aim of this study was to determine the total flavonoid and phenolic contents of n-butanol extract of Samanea saman leaf, and to evaluate the antibacterial activity towards Escherechia coli and Staphylococcus aureus. Extraction of compounds was done by ethanol 96%, followed by fractionation into n-hexane, ethyl acetate, and n-butanol. Determination of total flavonoid and phenolic contents was done by UV-Vis Spectrophotometer using standard of quersetin and galic acid respectively. In addition, antibacterial activity was evaluated by agar disc diffusion method. Extraction of 1000 g of Samanea saman leaf was obtained 80 g of ethanol extracts, fractionation of the extract was obtained 8.02 g of n-hexane extracts, 7.11 g of ethyl acetate extracts, 13.5 g of n-butanol extracts, and 14.16 g of aqueous extracts. Phytochemical screening of the n-butanol extracts revealed the presence of flavonoid and phenolic compounds. Total flavonoid and phenolic contents were successively 43.5798 mg QE/100g and 34.0180 mg GAE/100g. The butanol extracts inhibited the growth of S.aureus higher than the growth of E.coli. At the concentration of 2, 4, 6, 8 % (b/v), and positive control (meropenem μg/disc), inhibition zone towards S. aureus was successively 5.67, 9.33, 10.33, 12.00, and 32.33 mm, while the inhibition zone towards E. coli was1.33, 3.33, 4.33, 5.43, and 34.00 mm.

  10. Asymptomatic bacteriuria Escherichia coli strains

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Nielsen, E.M.; Klemm, Per

    2006-01-01

    Urinary tract infections (UTIs) affect millions of people each year. Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU) in humans. Persons affected by ABU may carry a particular E. coli strain for extended periods of time without any symptoms. In contrast to...... uropathogenic E. coli (UPEC) that cause symptomatic UTI, very little is known about the mechanisms by which these strains colonize the urinary tract. Here, we have investigated the growth characteristics in human urine as well as adhesin repertoire of nine ABU strains; the ability of ABU strains to compete...

  11. Fleroxacin resistance in Escherichia coli.

    OpenAIRE

    Chapman, J S; Bertasso, A; Georgopapadakou, N H

    1989-01-01

    Spontaneous fleroxacin-resistant mutants of Escherichia coli K-12 were isolated at a frequency of 10(-10) to 10(-11) mutants per CFU plated. All mutants exhibited quinolone-resistant replicative DNA biosynthesis, and 4 of 11 mutants also had decreased amounts of OmpF or OmpC porin. None of the mutants had changes solely in porin proteins.

  12. Development of predictive models for the effects of gamma radiation, irradiation temperature, pH, and modified atmosphere packaging on Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, salmonella typhimurium and Staphylococcus aureus

    International Nuclear Information System (INIS)

    Predictive models incorporating the effects of temperature on the inactivation by gamma irradiation of the food-borne pathogens Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus were developed and converted to forms suitable for incorporation into the ARS Pathogen Modelling Program. Because industrial radiation processors might use dry ice with frozen samples and up to ambient temperature, a range of -76 to +20 deg. C included in the study. In each case the survival of the pathogen was greater when the product was frozen at the time of irradiation. L. monocytogenes cells surviving 2 kGy irradiation could multiply on cooked but not on raw turkey meat stored at 7 deg. C for 21 days. (author)

  13. Staphylococcal phosphoenolpyruvate-dependent phosphotransferase system: purification and characterization of the mannitol-specific enzyme III/sup mtl/ of Staphylococcus aureus and Staphylococcus carnosus and homology with the enzyme II/sup mtl/ of Escherichia coli

    International Nuclear Information System (INIS)

    Enzyme III/sup mtl/ is part of the mannitol phosphotransferase system of Staphylococcus aureus and Staphylococcus carnosus and is phosphorylated by phosphoenolpyruvate in a reaction sequence requiring enzyme I (phosphoenolpyruvate-protein phosphotransferase) and the histidine-containing protein HPr. In this paper, the authors report the isolation of III/sup mtl/ from both S. aureus and S. carnosus and the characterization of the active center. After phosphorylation of III/sup mtl/ with [32P]PEP, enzyme I, and HPr, the phosphorylated protein was cleaved with endoproteinase GLu(C). The amino acid sequence of the S. aureus peptide carrying the phosphoryl group was found to be Gln-Val-Val-Ser-Thr-Phe-Met-Gly-Asn-Gly-Leu-Ala-Ile-Pro-His-Gly-Thr-Asp-Asp. The corresponding peptide from S. carnosus shows an equal sequence except that the first residue is Ala instead of Gln. These peptides both contain a single histidyl residue which they assume to carry the phosphoryl group. All proteins of the PTS so far investigated indeed carry the phosphoryl group attached to a histidyl residue. According to sodium dodecyl sulfate gels, the molecular weight of the III/sup mtl/ proteins was found to be 15,000. They have also determined the N-terminal sequence of both proteins. Comparison of the III/sup mtl/ peptide sequences and the C-terminal part of the enzyme II/sup mtl/ of Escherichia coli reveals considerable sequence homology, which supports the suggestion that II/sup mtl/ of E. coli is a fusion protein of a soluble III protein with a membrane-bound enzyme II

  14. Asymptomatic bacteriuria Escherichia coli strains

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Nielsen, E.M.; Klemm, Per

    2006-01-01

    Urinary tract infections (UTIs) affect millions of people each year. Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU) in humans. Persons affected by ABU may carry a particular E. coli strain for extended periods of time without any symptoms. In contrast to...... uropathogenic E. coli (UPEC) that cause symptomatic UTI, very little is known about the mechanisms by which these strains colonize the urinary tract. Here, we have investigated the growth characteristics in human urine as well as adhesin repertoire of nine ABU strains; the ability of ABU strains to compete...... against the UPEC strain CFT073 was also studied. The different ABU strains displayed a wide variety of the measured characteristics. Half of the ABU strains displayed functional type 1 fimbriae while only one expressed functional P fimbriae. A good correlation between the growth rate of a particular...

  15. Quantitative resistance level (MIC) of bacterial pathogens (Escherichia coli, Pasteurella multocida, Pseudomonas aeruginosa, Salmonella sp., Staphylococcus aureus) isolated from chickens and turkeys: national resistance monitoring by the BVL 2004/2005.

    Science.gov (United States)

    Wallmann, Jürgen; Schröer, Ulrike; Kaspar, Heike

    2007-01-01

    In the study 2004/2005, the current quantitative resistance level of Escherichia coli, Pasteurella multocida, Pseudomonas aeruginosa, Salmonella sp. and Staphylococcus aureus from chickens and turkeys was determined for the first time within the framework of the National Resistance Monitoring of the Federal Office of Consumer Protection and Food Safety (BVL). The objective was to implement a valid database on the basis of which the development and spread of resistance can be evaluated and monitored. During the investigation period from January 2004 to February 2005,927 strains were collected and 857 (92%) bacteria strains which corresponded to the specifications of the study protocol were tested with the broth microdilution method to determine the in vitro susceptibility (minimum inhibitory concentration) to 22 to 28 antimicrobial agents or antibiotic combinations. The results document a prevalence of resistance that exceeds that of bacterial pathogens of other animal species, especially in the case of tetracycline. Apart for S. aureus, clinical resistance to fluoroquinolones can still be considered low in poultry pathogens (E. coli approx. 2%). By applying the MICG of 4 mg/L for enrofloxacin, a susceptibility of approximately 78 % was calculated for S. aureus. A comparison of the prevalence of resistance between chickens and turkeys, showed that a slightly higher prevalence of resistance can be expected in turkeys. Differences between the susceptibility data of chicks and adult animals could only be found in turkeys. In the case of E. coli, the prevalence of resistance of strains isolated from adult turkeys was up to 10% higher than those isolated from chicks for the corresponding antimicrobial agents. It must be pointed out that the number of E. coli strains from adult turkeys was much higher (n = 194) than the number from turkey chicks (n = 21). The results indicate clearly that in a resistance monitoring system it is necessary to categorise poultry by animal

  16. Infection strategies of enteric pathogenic Escherichia coli

    OpenAIRE

    Clements, Abigail; Young, Joanna C.; Constantinou, Nicholas; Frankel, Gad

    2012-01-01

    Enteric Escherichia coli (E. coli) are both natural flora of humans and important pathogens causing significant morbidity and mortality worldwide. Traditionally enteric E. coli have been divided into 6 pathotypes, with further pathotypes often proposed. In this review we suggest expansion of the enteric E. coli into 8 pathotypes to include the emerging pathotypes of adherent invasive E. coli (AIEC) and Shiga-toxin producing enteroaggregative E. coli (STEAEC). The molecular mechanisms that all...

  17. Evaluating Antimicrobial Effects of Centaurea Plant’s Essential Oil on Pathogenic Bacteria: Staphylococcus Aureus, Staphylococcus Epidermidis, and Escherichia Coli Isolated from Clinical Specimens

    Directory of Open Access Journals (Sweden)

    Haedeh Mobaiyen

    2016-03-01

    Full Text Available Background & Objectives :Nowadays, development of drug resistance against chemical antimicrobial drugs has attracted attention using medicinal plants in treatment of infections. The aim of this study is to evaluate the antimicrobial effects of two species of Centaurea plant’s essential oil on drug resistant clinical isolates of three pathogenic isolates. Materials & Methods :The studied plants were collected from Marand city in East Azerbaijan, Iran and were confirmed as Centaurea Depressa M.B. and Centaurea Cyanus L. by botanists of Iran Agriculture Organization. The essential oil of these plants (Stems and leaf were extracted via steam distillation method by Clevenger, and their antimicrobial effects were studied by well diffusion method in the abovementioned bacteria. The components of essential oil were identified by injection to gas chromatography linked to mass spectrometry (GC/M. Results :The results of this study prove that the essential oils from the abovementioned plants have bactericidal effects. The most antibacterial effect is observed in Escherichia coli strains. The results of GC/MS chromatography reveal that the essential oils of Centaurea Depressa M.B. and Centaurea Cyanus L. have 28 and 32 compounds, respectively. Conclusion: This study confirmed that the grasses could be used in medicinal plants group with antibacterial properties. However, their effects in vivo must be evaluated and the most effective component of them must be identified carefully so that they can be applied commonly as an alternative synthetic drug in treating infections.

  18. Multiplex PCR and a chromogenic DNA macroarray for the detection of Listeria monocytogens, Staphylococcus aureus, Streptococcus agalactiae, Enterobacter sakazakii, Escherichia coli O157:H7, Vibrio parahaemolyticus, Salmonella spp. and Pseudomonas fluorescens in milk and meat samples.

    Science.gov (United States)

    Chiang, Yu-Cheng; Tsen, Hau-Yang; Chen, Hsin-Yen; Chang, Yu-Hsin; Lin, Chien-Ku; Chen, Chih-Yuan; Pai, Wan-Yu

    2012-01-01

    Food products, such as milk and meat products including cheese, milk powder, fermented milk, sausage, etc. are susceptible to the contamination by pathogenic and deteriorative bacteria. These bacteria include Listeria monocytogens, Staphylococcus aureus, Enterobacter sakazakii, Escherichia coli O157:H7, Salmonella spp., Vibrio parahaemolyticus, Streptococcus agalactiae and Pseudomonas fluorescens, etc. Traditional methods for the detection of these microorganisms are laborious and time consuming. Therefore, rapid and accurate diagnostic methods are needed. In this study, we designed the DNA probes and PCR primers for the detection of aforementioned microorganisms. By using two sets of multiplex PCR, followed by a chromogenic macroarray system, these organisms in milk or other food products could be simultaneously detected. When the system was used for the inspection of milk or meat homogenate containing 10(0) target cells per milliliter or gram of the sample, all these bacterial species could be identified after an 8h pre-enrichment step. The system consisting of a multiplex PCR step followed by macroarray allowed us to detect multiple target bacterial species simultaneously without the use of agarose gel electrophoresis. Compared to the commonly used multiplex PCR method, this approach has the additional advantage of detecting more bacterial strains because some bacterial strains generate PCR products with the same molecular sizes which can be differentiated by macroarray but not by electrophoresis. PMID:22101309

  19. Thiol-sensitive promoters of Escherichia coli.

    OpenAIRE

    Javor, G T; Stringer, C D; Ryu, J.

    1988-01-01

    Mu dX(lac) insertion mutants of Escherichia coli CSH50 in which the expression of the lacZ gene was sensitive to the presence of exogenous 1-thioglycerol or dithiothreitol were isolated. Both stimulatory and inhibitory mutants were found. The existence of several thiol-sensitive promoters suggests that exogenous thiols may provoke global stress responses in E. coli.

  20. Infectious endocarditis caused by Escherichia coli

    DEFF Research Database (Denmark)

    Lauridsen, Trine Kiilerich; Arpi, Magnus; Fritz-Hansen, Thomas;

    2011-01-01

    Although Escherichia coli is among the most common causes of Gram-negative bacteraemia, infectious endocarditis (IE) due to this pathogen is rare. A 67-y-old male without a previous medical history presented with a new mitral regurgitation murmur and persisting E. coli bacteraemia in spite of broad...

  1. Fimbrial adhesins from extraintestinal Escherichia coli

    DEFF Research Database (Denmark)

    Klemm, Per; Hancock, Viktoria; Schembri, Mark A.

    2010-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) represent an important subclass of E. coli that cause a wide spectrum of diseases in human and animal hosts. Fimbriae are key virulence factors of ExPEC strains. These long surface located rod-shaped organelles mediate receptor-specific attachment...

  2. Global gene expression in Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Schembri, Mark; Kjærgaard, K.; Klemm, Per

    2003-01-01

    antimicrobial treatments and host immune defence responses. Escherichia coli has been used as a model organism to study the mechanisms of growth within adhered communities. In this study, we use DNA microarray technology to examine the global gene expression profile of E. coli during sessile growth compared...

  3. 99mTechnetium labelled Escherichia coli

    International Nuclear Information System (INIS)

    Samples of a culture of unlabeled Escherichia coli were incubated with different concentrations of stannous chloride for various time periods. 99mTc (26.0 MBq) was added to each preparation and the results showed a labelling yield of 98% for E. coli. Since the bacterial viability of 99mTc-E. coli and E. coli did not show any statistical differences, these results demonstrate that labelling of E. coli with 99mTc does not modify the bacterial viability, and the radiolabelled bacteria may be a good model to study bacterial translocation

  4. Establishment and application of multiplex PCR detection method for Staphylococcus aureus,Streptococcus,Salmonella spp and Escherichia coli%链球菌、金黄色葡萄球菌、沙门菌和大肠杆菌多重PCR检测方法的建立及应用

    Institute of Scientific and Technical Information of China (English)

    许信刚; 杨丽花; 童德文

    2012-01-01

    根据NCBI上已收录的链球菌ef-tu基因、金黄色葡萄球菌nuc基因、沙门菌hut基因和大肠杆菌23SrRNA基因的序列,设计并合成4对特异性引物,通过优化多重PCR的反应条件,建立了能够同时检测4种细菌混合感染的多重PCR诊断方法。特异性分析结果表明,应用该方法可以从链球菌、金黄色葡萄球菌、沙门菌和大肠杆菌以及4种细菌的混合物中扩增出4条大小分别为197、278、495和652bp的特异性条带,其他对照组的检测结果均为阴性;敏感性分析表明,该方法对4种病原菌基因组DNA的检出量分别为链球菌25.6pg、金黄色葡萄球菌33.2pg、沙门菌35.7pg、大肠杆菌52.1pg;人工模拟感染样本检测表明,该方法能从混合感染的病料中特异地检测出4种病原菌。本试验建立的多重PCR方法具有特异性强,敏感度高,稳定性好的特点,可以有效的检测链球菌、金黄色葡萄球菌、沙门菌和大肠杆菌的混合感染。%A multiplex PCR assay was developed and evaluated for the clinical detection of Staphylococcus aureus,Streptococcus,Salmonella spp and Escherichia coli.Four pairs of primers were designed and synthesized according to highly conserved regions of the Streptococcus ef-tu gene,Staphylococcus aureus nuc gene,Salmonella spp hut gene and Escherichia coli 23SrRNA gene of NCBI.The multiplex PCR reaction condition was optimized and the multiplex PCR method for detecting the co-infection of Staphylococcus aureus,Streptococcus,Salmonella spp and Escherichia coli was established.The specificity test showed that a fragment of 197,278,495 and 652 bp was amplified from genomic DNA of Streptococcus,Staphylococcus aureus,Salmonella spp and Escherichia coli,respectively.No amplification was achieved from control groups of other bacteria.The sensitivity test showed that the multiplex PCR could detect genome DNA of 25.6 pg for Streptococcus,33.2 pg for Staphylococcus aureus,35.7 pg for Salmonella spp

  5. Control of Ribosome Synthesis in Escherichia coli

    DEFF Research Database (Denmark)

    Molin, Søren; Meyenburg, K. von; Måløe, O.;

    1977-01-01

    The rate of ribosome synthesis and accumulation in Escherichia coli during the transition after an energy source shift-down was analyzed. The shift was imposed on cultures of stringent and relaxed strains growing in glucose minimal medium by the addition of the glucose analogue {alpha}-methylgluc......The rate of ribosome synthesis and accumulation in Escherichia coli during the transition after an energy source shift-down was analyzed. The shift was imposed on cultures of stringent and relaxed strains growing in glucose minimal medium by the addition of the glucose analogue {alpha...

  6. Hydrogen production by recombinant Escherichia coli strains

    OpenAIRE

    Maeda, Toshinari; Sanchez‐Torres, Viviana; Thomas K Wood

    2012-01-01

    Summary The production of hydrogen via microbial biotechnology is an active field of research. Given its ease of manipulation, the best‐studied bacterium Escherichia coli has become a workhorse for enhanced hydrogen production through metabolic engineering, heterologous gene expression, adaptive evolution, and protein engineering. Herein, the utility of E. coli strains to produce hydrogen, via native hydrogenases or heterologous ones, is reviewed. In addition, potential strategies for increas...

  7. Native valve Escherichia coli endocarditis following urosepsis

    OpenAIRE

    Rangarajan, D.; Ramakrishnan, S.; Patro, K. C.; Devaraj, S.; V Krishnamurthy; Kothari, Y.; Satyaki, N.

    2013-01-01

    Gram-negative organisms are a rare cause of infective endocarditis. Escherichia coli, the most common cause of urinary tract infection and gram-negative septicemia involves endocardium rarely. In this case report, we describe infection of native mitral valve by E. coli following septicemia of urinary tract origin in a diabetic male; subsequently, he required prosthetic tissue valve replacement indicated by persistent sepsis and congestive cardiac failure.

  8. Draft Genome Sequences of Escherichia coli Isolates from Wounded Military Personnel.

    Science.gov (United States)

    Arivett, Brock A; Ream, Dave C; Fiester, Steven E; Kidane, Destaalem; Actis, Luis A

    2016-01-01

    Members of the Escherichia coli bacterial family have been grouped as ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens because of their extensive drug resistance phenotypes and increasing threat to human health. The genomes of six extended-spectrum β-lactamase (ESBL)-producing E. coli strains isolated from wounded military personnel were sequenced and annotated. PMID:27516515

  9. Beta-alanine synthesis in Escherichia coli.

    OpenAIRE

    Cronan, J. E.

    1980-01-01

    The enzyme, aspartate 1-decarboxylase (L-aspartate 1-carboxy-lyase; EC 4.1.1.15), that catalyzes the reaction aspartate leads to beta-alanine + CO2 was found in extracts of Escherichia coli. panD mutants of E. coli are defective in beta-alanine biosynthesis and lack aspartate 1-decarboxylase. Therefore, the enzyme functions in the biosynthesis of the beta-alanine moiety of pantothenate. The genetic lesion in these mutants is closely linked to the other pantothenate (pan) loci of E. coli K-12.

  10. Comparison of 61 Sequenced Escherichia coli Genomes

    DEFF Research Database (Denmark)

    Lukjancenko, Oksana; Wassenaar, T. M.; Ussery, David

    2010-01-01

    Escherichia coli is an important component of the biosphere and is an ideal model for studies of processes involved in bacterial genome evolution. Sixty-one publically available E. coli and Shigella spp. sequenced genomes are compared, using basic methods to produce phylogenetic and proteomics...... the pan-genome and about 80% of a typical genome; some of these variable genes tend to be co-localized on genomic islands. The diversity within the species E. coli, and the overlap in gene content between this and related species, suggests a continuum rather than sharp species borders in this group of...

  11. Cellular chain formation in Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; Klemm, Per

    2009-01-01

    In this study we report on a novel structural phenotype in Escherichia coli biofilms: cellular chain formation. Biofilm chaining in E. coli K-12 was found to occur primarily by clonal expansion, but was not due to filamentous growth. Rather, chain formation was the result of intercellular......; type I fimbriae expression significantly reduced cellular chain formation, presumably by steric hindrance. Cellular chain formation did not appear to be specific to E coli K-12. Although many urinary tract infection (UTI) isolates were found to form rather homogeneous, flat biofilms, three isolates...

  12. Deuterium incorporation into Escherichia-coli proteins

    DEFF Research Database (Denmark)

    Lederer, H.; May, R. P.; Kjems, Jørgen;

    1986-01-01

    -dependent RNA polymerase of Escherichia coli match when RNA polymerase is isolated from cells grown in a medium containing 46% D2O and unlabelled glucose as carbon source. Their contrasts vanish simultaneously in a dialysis buffer containing 65% D2O. An expression was evaluated which allows the calculation of...... the degree of deuteration and match point of any E. coli protein from the D2O content of the growth medium, taking the 2H incorporation into RNA polymerase amino acids to be representative for all amino acids in E. coli proteins. The small-angle scattering results, on which the calculation of the...

  13. Control of Ribosome Synthesis in Escherichia coli

    DEFF Research Database (Denmark)

    Molin, Søren; Meyenburg, K. von; Måløe, O.; Trier Hansen, M.; Pato, M. L.

    1977-01-01

    The rate of ribosome synthesis and accumulation in Escherichia coli during the transition after an energy source shift-down was analyzed. The shift was imposed on cultures of stringent and relaxed strains growing in glucose minimal medium by the addition of the glucose analogue {alpha...

  14. Escherichia Coli--Key to Modern Genetics.

    Science.gov (United States)

    Bregegere, Francois

    1982-01-01

    Mid-nineteenth century work by Mendel on plant hybrids and by Pasteur on fermentation gave birth by way of bacterial genetics to modern-day molecular biology. The bacterium Escherichia Coli has occupied a key position in genetic studies leading from early gene identification with DNA to current genetic engineering using recombinant DNA technology.…

  15. Detection of O antigens in Escherichia coli

    Science.gov (United States)

    Lipopolysaccharide on the surface of Escherichia coli constitute the O antigens, which are important virulence factors that are targets of both the innate and adaptive immune system and play a major role in host-pathogen interactions. O antigens that are responsible for antigenic specificity of the ...

  16. Progressive segregation of the Escherichia coli chromosome

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck; Youngren, Brenda; Hansen, Flemming G.;

    2006-01-01

    We have followed the fate of 14 different loci around the Escherichia coli chromosome in living cells at slow growth rate using a highly efficient labelling system and automated measurements. Loci are segregated as they are replicated, but with a marked delay. Most markers segregate in a smooth...

  17. The eclipse period of Escherichia coli

    DEFF Research Database (Denmark)

    von Freiesleben, Ulrik; Krekling, Martin A.; Hansen, Flemming G.;

    2000-01-01

    The minimal time between successive initiations on the same origin (the eclipse) in Escherichia coli was determined to be approximately 25-30 min. An inverse relationship was found between the length of the eclipse and the amount of Dam methyltransferase in the cell, indicating that the eclipse...

  18. Leaner and meaner genomes in Escherichia coli

    DEFF Research Database (Denmark)

    Ussery, David

    2006-01-01

    A 'better' Escherichia coli K-12 genome has recently been engineered in which about 15% of the genome has been removed by planned deletions. Comparison with related bacterial genomes that have undergone a natural reduction in size suggests that there is plenty of scope for yet more deletions....

  19. Vibrio parahaemolyticus, enterotoxigenic Escherichia coli, enterohemorrhagic Escherichia coli and Vibrio cholerae

    OpenAIRE

    Takeda, Yoshifumi

    2011-01-01

    This review highlighted the following: (i) pathogenic mechanism of the thermostable direct hemolysin produced by Vibrio parahaemolyticus, especially on its cardiotoxicity, (ii) heat-labile and heat-stable enterotoxins produced by enterotoxigenic Escherichia coli, especially structure–activity relationship of heat-stable enterotoxin, (iii) RNA N-glycosidase activity of Vero toxins (VT1 and VT2) produced by enterohemorrhagic Escherichia coli O157:H7, (iv) discovery of Vibrio cholerae O139, (v) ...

  20. Pathogenomics of uropathogenic Escherichia coli

    OpenAIRE

    Agarwal, J.; Srivastava, S.; Singh, M.

    2012-01-01

    Subset of faecal E. coli that can enter, colonize urinary tract and cause infection are known as uropathogenic E. coli (UPEC). UPEC strains act as opportunistic intracellular pathogens taking advantage of host susceptibility using a diverse array of virulence factors. Presence of specific virulence associated genes on genomic/pathogenicity islands and involvement of horizontal gene transfer appears to account for evolution and diversity of UPEC. Recent success in large-scale genome sequencing...

  1. Synergistic effects in mixed Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Reisner, A.; Holler, B.M.; Molin, Søren;

    2006-01-01

    pathways governing development of more complex heterogeneous communities. In this study, we established a laboratory model where biofilm-stimulating effects due to interactions between genetically diverse strains of Escherichia coli were monitored. Synergistic induction of biofilm formation resulting from...... the cocultivation of 403 undomesticated E. coli strains with a characterized E. coli K-12 strain was detected at a significant frequency. The survey suggests that different mechanisms underlie the observed stimulation, yet synergistic development of biofilm within the subset of E. coli isolates (n...... = 56) exhibiting the strongest effects was most often linked to conjugative transmission of natural plasmids carried by the E. coli isolates (70%). Thus, the capacity of an isolate to promote the biofilm through cocultivation was (i) transferable to the K-12 strain, (ii) was linked with the acquisition...

  2. Escherichia coli in Europe: An Overview

    Directory of Open Access Journals (Sweden)

    Nerino Allocati

    2013-11-01

    Full Text Available Escherichia coli remains one of the most frequent causes of several common bacterial infections in humans and animals. E. coli is the prominent cause of enteritis, urinary tract infection, septicaemia and other clinical infections, such as neonatal meningitis. E. coli is also prominently associated with diarrhoea in pet and farm animals. The therapeutic treatment of E. coli infections is threatened by the emergence of antimicrobial resistance. The prevalence of multidrug-resistant E. coli strains is increasing worldwide principally due to the spread of mobile genetic elements, such as plasmids. The rise of multidrug-resistant strains of E. coli also occurs in Europe. Therefore, the spread of resistance in E. coli is an increasing public health concern in European countries. This paper summarizes the current status of E. coli strains clinically relevant in European countries. Furthermore, therapeutic interventions and strategies to prevent and control infections are presented and discussed. The article also provides an overview of the current knowledge concerning promising alternative therapies against E. coli diseases.

  3. Molecular Characterization of Diarrheagenic Escherichia coli from Libya

    OpenAIRE

    Ali, Mostafa Mohamed M; Mohamed, Zienat Kamel; Klena, John D.; Ahmed, Salwa Fouad; Tarek A.A. Moussa; Ghenghesh, Khalifa Sifaw

    2012-01-01

    Diarrheagenic Escherichia coli (DEC) are important enteric pathogens that cause a wide variety of gastrointestinal diseases, particularly in children. Escherichia coli isolates cultured from 243 diarrheal stool samples obtained from Libyan children and 50 water samples were screened by polymerase chain reaction (PCR) for genes characteristic of enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enterohemorrhagic E. coli (EHEC), and enteroinvasiv...

  4. Pathogenomics of uropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    J Agarwal

    2012-01-01

    Full Text Available Subset of faecal E. coli that can enter, colonize urinary tract and cause infection are known as uropathogenic E. coli (UPEC. UPEC strains act as opportunistic intracellular pathogens taking advantage of host susceptibility using a diverse array of virulence factors. Presence of specific virulence associated genes on genomic/pathogenicity islands and involvement of horizontal gene transfer appears to account for evolution and diversity of UPEC. Recent success in large-scale genome sequencing and comparative genomics has helped in unravelling UPEC pathogenomics. Here we review recent findings regarding virulence characteristics of UPEC and mechanisms involved in pathogenesis of urinary tract infection.

  5. Escherichia coli bacteriuria and contraceptive method.

    Science.gov (United States)

    Hooton, T M; Hillier, S; Johnson, C; Roberts, P L; Stamm, W E

    1991-01-01

    We evaluated the effects of contraceptive method on the occurrence of bacteriuria and vaginal colonization with Escherichia coli in 104 women who were evaluated prior to having sexual intercourse, the morning after intercourse, and 24 hours later. After intercourse, the prevalence of E coli bacteriuria increased slightly in oral contraceptive users but dramatically in both foam and condom users and diaphragm-spermicide users. Twenty-four hours later, the prevalence of bacteriuria remained significantly elevated only in the latter two groups. Similarly, vaginal colonization with E coli was more dramatic and persistent in users of diaphragm-spermicide and foam and condoms. Vaginal colonization with Candida species, enterococci, and staphylococci also increased significantly in diaphragm-spermicide users after intercourse. We conclude that use of the diaphragm with spermicidal jelly or use of a spermicidal foam with a condom markedly alters normal vaginal flora and strongly predisposes users to the development of vaginal colonization and bacteriuria with E coli. PMID:1859519

  6. Dynamics of chromosome segregation in Escherichia coli

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck

    2007-01-01

    Since the 1960’es the conformation and segregation of the chromosome in Escherichia coli has been a subject of interest for many scientists. However, after 40 years of research, we still know incredibly little about how the chromosome is organized inside the cell, how it manages to duplicate this...... and reliable method enabled us to start the analysis on the distribution of various chromosomal loci inside slowly growing cells. With the actual counting and measuring no longer being any problem we could easily analyze 14 loci distributed on the E.coli chromosome. More than 15.000 cells were...... on the P1 par system. Using the new system, which is based on the pMT1 par system from Yersenia pestis, we labeled loci on opposite sides of the E.coli chromosome simultaneously and were able to show that the E.coli chromosome is organized with one chromosomal arm in each cell half. This astounding...

  7. Infectious endocarditis caused by Escherichia coli

    DEFF Research Database (Denmark)

    Lauridsen, Trine Kiilerich; Arpi, Magnus; Fritz-Hansen, Thomas;

    2011-01-01

    Although Escherichia coli is among the most common causes of Gram-negative bacteraemia, infectious endocarditis (IE) due to this pathogen is rare. A 67-y-old male without a previous medical history presented with a new mitral regurgitation murmur and persisting E. coli bacteraemia in spite of broad......-spectrum intravenous antibiotics. Transthoracic and transoesophageal echocardiography revealed a severe mitral endocarditis. E. coli DNA was identified from the mitral valve and the vegetation, and no other pathogen was found. The case was further complicated by spondylodiscitis and bilateral endophthalmitis. Extra......-intestinal pathogenic E. coli (ExPEC) are able to colonize tissue outside the gastrointestinal tract and contain a variety of virulence factors that may enable the pathogens to invade and induce infections in the cardiac endothelia. In these cases echocardiography as the imaging technology is of paramount importance...

  8. Identification and Prevalence of Escherichia coli and Escherichia coli O157: H7 in Foods

    Directory of Open Access Journals (Sweden)

    Ancuta Mihaela Rotar

    2013-11-01

    Full Text Available The objective of this study is to investigate the incidence of Escherichia coli in animal and non-animal foods, and mainly the incidence of the serotype O157: H7 producing verotoxin. The presence of common Escherichia coli and Escherichia coli O157: H7 in various foods (of animal and non animal origin was performed in Transylvania area. We analyzed a total of one hundred forty-one samples of minced meat, one hundred twenty-six samples of meat , twenty six samples of meat products, five samples of alcoholic beverages, three samples of seafood, one hundred samples of cheese from pasteurized milk, seventeen samples of butter, four samples of vegetables and one sample of milk powder, using the standard cultural method and Vidas Eco method for E. coli O157: H7 strains. E. coli was identified in 50 samples of minced meat, 55 samples of meat prepared, 4 samples of meat products, 2 samples of alcoholic beverages, 25 samples of cheese from pasteurized milk, 6 samples of butter and 1 sample of vegetables. In this study were not been identified any foods contaminated with the E. coli O157: H7 serotype. The results of this reasearch have demostrated that E. coli wich represents a hygienic indicator of recent food contamination, can be destroyed with heat treatment and hygienic handling of foods. Our country over the years has been among the few countries where the incidence of the E. coli O157: H7 serotype has been minimal.

  9. Designed Phosphoprotein Recognition in Escherichia coli

    OpenAIRE

    Sawyer, Nicholas; Gassaway, Brandon M.; Haimovich, Adrian D.; Isaacs, Farren J.; Rinehart, Jesse; Regan, Lynne

    2014-01-01

    Protein phosphorylation is a central biological mechanism for cellular adaptation to environmental changes. Dysregulation of phosphorylation signaling is implicated in a wide variety of diseases. Thus, the ability to detect and quantify protein phosphorylation is highly desirable for both diagnostic and research applications. Here we present a general strategy for detecting phosphopeptide–protein interactions in Escherichia coli. We first redesign a model tetratricopeptide repeat (TPR) protei...

  10. Endonuclease IV (nfo) mutant of Escherichia coli.

    OpenAIRE

    Cunningham, R P; Saporito, S M; Spitzer, S G; Weiss, B

    1986-01-01

    A cloned gene, designated nfo, caused overproduction of an EDTA-resistant endonuclease specific for apurinic-apyrimidinic sites in DNA. The sedimentation coefficient of the enzyme was similar to that of endonuclease IV. An insertion mutation was constructed in vitro and transferred from a plasmid to the Escherichia coli chromosome. nfo mutants had an increased sensitivity to the alkylating agents methyl methanesulfonate and mitomycin C and to the oxidants tert-butyl hydroperoxide and bleomyci...

  11. Endonuclease III (nth) mutants of Escherichia coli.

    OpenAIRE

    Cunningham, R P; Weiss, B

    1985-01-01

    Two strains that overproduce endonuclease III were found in a colony bank containing hybrid ColE1-Escherichia coli plasmids. The enzyme was identified in crude extracts by the degradation of partially depyrimidinated DNA in the presence of EDTA, by its sedimentation velocity, and by its associated thymine glycol-DNA glycosylase activity. An insertion mutation was produced by cloning the kanamycin-resistance gene of Tn5 into the plasmid copy of the nth gene. The mutation was then transferred t...

  12. Growth of Escherichia coli on nanocrystalline diamond

    Czech Academy of Sciences Publication Activity Database

    Jurková, Blanka; Kozak, Halyna; Artemenko, Anna; Ukraintsev, Egor; Beranová, J.; Konopásek, I.; Kromka, Alexander

    Ostrava: TANGER Ltd, 2015 - (Shrbená, J.; Zbořil, R.), s. 4318 ISBN 9788087294598. [NANOCON 2015. International Conference /7./. Brno (CZ), 14.10.2015-16.10.2015] R&D Projects: GA ČR GA15-01687S Institutional support: RVO:68378271 Keywords : nanocrystalline diamond * bacteria * Escherichia coli * anti-adhesive * CDC Bioreactor Subject RIV: BM - Solid Matter Physics ; Magnetism

  13. Multiplex PCR Assay for Identification of Human Diarrheagenic Escherichia coli

    OpenAIRE

    Toma, Claudia; Lu, Yan; Higa, Naomi; Nakasone, Noboru; Chinen, Isabel; Baschkier, Ariela; Rivas, Marta; Iwanaga, Masaaki

    2003-01-01

    A multiplex PCR assay for the identification of human diarrheagenic Escherichia coli was developed. The targets selected for each category were eae for enteropathogenic E. coli, stx for Shiga toxin-producing E. coli, elt and est for enterotoxigenic E. coli, ipaH for enteroinvasive E. coli, and aggR for enteroaggregative E. coli. This assay allowed the categorization of a diarrheagenic E. coli strain in a single reaction tube.

  14. Action of sodium deoxycholate on Escherichia coli

    International Nuclear Information System (INIS)

    Sodium deoxycholate is used in a number of bacteriological media for the isolation and classification of gram-negative bacteria from food and the environment. Initial experiments to study the effect of deoxycholate on the growth parameters of Escherichia coli showed an increase in the lag time constant and generation time and a decrease in the growth rate constant total cell yield of this microorganisms. Cell fractionation studies indicated that sodium deoxycholate at levels used in bacteriological media interferes with the incorporation of [U-14C]glucose into the cold-trichloroacetic acid-soluble, ethanol-soluble, and trypsin-soluble cellular fractions of E. coli. Finally, sodium deoxycholate interfered with the flagellation and motility of Proteus mirabilis and E. coli. It would appear then that further improvement of the deoxycholate medium may be in order

  15. Action of sodium deoxycholate on Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    D' Mello, A.; Yotis, W.W.

    1987-08-01

    Sodium deoxycholate is used in a number of bacteriological media for the isolation and classification of gram-negative bacteria from food and the environment. Initial experiments to study the effect of deoxycholate on the growth parameters of Escherichia coli showed an increase in the lag time constant and generation time and a decrease in the growth rate constant total cell yield of this microorganisms. Cell fractionation studies indicated that sodium deoxycholate at levels used in bacteriological media interferes with the incorporation of (U-/sup 14/C)glucose into the cold-trichloroacetic acid-soluble, ethanol-soluble, and trypsin-soluble cellular fractions of E. coli. Finally, sodium deoxycholate interfered with the flagellation and motility of Proteus mirabilis and E. coli. It would appear then that further improvement of the deoxycholate medium may be in order.

  16. Usage of antimicrobials on 60 dairy farms in Northern Germany and characterization of Methicillin-resistant staphylococcus aureus (MRSA) and extended spectrum beta-lactamases producing Escherichia coli (ESBLs-producing E. coli) isolated from bulk tank milk samples

    OpenAIRE

    Kreausukon, Khwanchai

    2011-01-01

    Das Ziel der Studie war, Informationen über den Einsatz von Antibiotika in deutschen Milchkuhherden zu sammeln. Zudem sollte auf das Vorkommen von MRSA und ESBL-produzierenden E. coli in Tankmilchproben untersucht werden. Fragebögen wurden unter den Herdenmanagern von 60 norddeutschen Betrieben (Herdengröße von 25 bis 3000 Tiere) verteilt, die auf freiwilliger Basis an den Untersuchungen teilnahmen. Tankmilchproben wurden in den Betrieben einmalig entnommen und auf das Vorkommen von MRSA u...

  17. Epidemiology and clinical manifestations of enteroaggregative Escherichia coli

    DEFF Research Database (Denmark)

    Hebbelstrup Jensen, Betina; Olsen, Katharina E P; Struve, Carsten;

    2014-01-01

    Enteroaggregative Escherichia coli (EAEC) represents a heterogeneous group of E. coli strains. The pathogenicity and clinical relevance of these bacteria are still controversial. In this review, we describe the clinical significance of EAEC regarding patterns of infection in humans, transmission,...

  18. Ethanol production by Escherichia coli KO11; Producao de etanol por Escherichia coli KO11

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Katia Gianni de Carvalho [Sao Paulo Univ., SP (Brazil). Faculdade de Ciencias Farmaceuticas. Lab. de Microbiologia de Alimentos]. E-mail: gianni@usp.br; Takahashi, Caroline Maki; Alterthum, Flavio [Sao Paulo Univ., SP (Brazil). Inst. de Ciencias Biomedicas. Dept. de Microbiologia

    2002-08-01

    This paper discusses the potential use of Escherichia coli KO11 in production of ethanol, based on observation that this organism can efficiently metabolize sugar complex moistures obtained from the acid hydrolysis of lignocellulose materials such as sugar-cane bagasse, corncob, corn husk, Pinus sp and oak wood.

  19. Expression of maize prolamins in Escherichia Coli

    International Nuclear Information System (INIS)

    We have constructed a cDNA expression library of developing corn (Zea manys L.) endosperm using plasmid pUC8 as vector and Escherichia coli strain DH1 as host. The expression library was screened with non-radioactive immunological probes to detect the expression of gamma-zein and alpha-zein. When anti-gamma-zein antibody was used as the probe, 23 colonies gave positive reactions. The lengths of cDNA inserts of the 23 colonies were found to be 250-900 base pairs. When anti-alpha zein antibody was used, however, fewer colonies gave positive reactions. The library was also screened by colony-hybridization with 32P-labeled DNA probes. Based on immunological and hybridization screening of the library and other evidence, we conclude that alpha-zein was either toxic to E. coli cells or rapidly degraded whereas gamma-zein and its fragments were readily expressed. (author)

  20. Global gene expression in Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Schembri, Mark; Kjærgaard, K.; Klemm, Per

    2003-01-01

    antimicrobial treatments and host immune defence responses. Escherichia coli has been used as a model organism to study the mechanisms of growth within adhered communities. In this study, we use DNA microarray technology to examine the global gene expression profile of E. coli during sessile growth compared...... with planktonic growth. Genes encoding proteins involved in adhesion (type 1 fimbriae) and, in particular, autoaggregation (Antigen 43) were highly expressed in the adhered population in a manner that is consistent with current models of sessile community development. Several novel gene clusters were...... induced upon the transition to biofilm growth, and these included genes expressed under oxygen-limiting conditions, genes encoding (putative) transport proteins, putative oxidoreductases and genes associated with enhanced heavy metal resistance. Of particular interest was the observation that many of the...

  1. Escherichia coli O157 infections and unpasteurised milk

    NARCIS (Netherlands)

    Allerberger, F; Wagner, M; Schweiger, P; Rammer, H P; Resch, A; Dierich, M P; Friedrich, A W; Karch, H

    2001-01-01

    We report on two children with Escherichia coli O157 infection, one of whom developed haemolytic uraemic syndrome (HUS). Both had drunk raw cows or goats milk in the week before their illness. Molecular subtyping identified a sorbitol fermenting Escherichia coli O157:H isolate from a dairy cow. This

  2. Chromatin architecture and gene expression in Escherichia coli

    DEFF Research Database (Denmark)

    Willenbrock, Hanni; Ussery, David

    2004-01-01

    Two recent genome-scale analyses underscore the importance of DNA topology and chromatin structure in regulating transcription in Escherichia coli.......Two recent genome-scale analyses underscore the importance of DNA topology and chromatin structure in regulating transcription in Escherichia coli....

  3. Escherichia coli clearance after splenic autotransplants

    International Nuclear Information System (INIS)

    Background: Splenic autotransplantation seems to be the only alternative for preservation of splenic tissue, after total splenectomy. The present study was carried out to analyze Escherichia coli depuration by mononuclear phagocyte system organs after total splenectomy and splenic autotransplantation. Methods: We utilized an experimental model including young and adult Wistar rats, of both sexes, submitted to total splenectomy and splenic autotransplantation. The evaluation method was intravenous inoculation of a suspension of Escherichia coli labeled with technetium-99m. We analyzed bacteria uptake by mononuclear phagocyte system organs and bacteria remnant in the bloodstream. Results: There was no difference between young and adult animals in bacteria uptake by mononuclear phagocyte system organs. In the comparison of groups, it was found out that the mean percent uptake by spleen and liver of animals in the control group was higher than that observed for animals with splenic implants. However, bacteria uptake in the lung was higher in the splenic implant group than in the control group. Although spleen bacteria uptake in the control group animals has been higher than that of animals in the splenic implant group, the remnant bacteria in the bloodstream was similar. Animals submitted to isolated total splenectomy showed higher bacteria remnant in the bloodstream than animals of the control group or the group submitted to total splenectomy combined with splenic autotransplantation. Conclusion: Our results indicate that autogenous splenic implant is efficacious in bacteria depuration in rats, by means of their macrophages phagocytosis. In addition, it does not modify bacteria removal function of liver and lung

  4. Production of glycoprotein vaccines in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Ihssen Julian

    2010-08-01

    Full Text Available Abstract Background Conjugate vaccines in which polysaccharide antigens are covalently linked to carrier proteins belong to the most effective and safest vaccines against bacterial pathogens. State-of-the art production of conjugate vaccines using chemical methods is a laborious, multi-step process. In vivo enzymatic coupling using the general glycosylation pathway of Campylobacter jejuni in recombinant Escherichia coli has been suggested as a simpler method for producing conjugate vaccines. In this study we describe the in vivo biosynthesis of two novel conjugate vaccine candidates against Shigella dysenteriae type 1, an important bacterial pathogen causing severe gastro-intestinal disease states mainly in developing countries. Results Two different periplasmic carrier proteins, AcrA from C. jejuni and a toxoid form of Pseudomonas aeruginosa exotoxin were glycosylated with Shigella O antigens in E. coli. Starting from shake flask cultivation in standard complex medium a lab-scale fed-batch process was developed for glycoconjugate production. It was found that efficiency of glycosylation but not carrier protein expression was highly susceptible to the physiological state at induction. After induction glycoconjugates generally appeared later than unglycosylated carrier protein, suggesting that glycosylation was the rate-limiting step for synthesis of conjugate vaccines in E. coli. Glycoconjugate synthesis, in particular expression of oligosaccharyltransferase PglB, strongly inhibited growth of E. coli cells after induction, making it necessary to separate biomass growth and recombinant protein expression phases. With a simple pulse and linear feed strategy and the use of semi-defined glycerol medium, volumetric glycoconjugate yield was increased 30 to 50-fold. Conclusions The presented data demonstrate that glycosylated proteins can be produced in recombinant E. coli at a larger scale. The described methodologies constitute an important step

  5. Shigella Strains Are Not Clones of Escherichia coli but Sister Species in the Genus Escherichia

    OpenAIRE

    Zuo, Guanghong; Xu, Zhao; Hao, Bailin

    2012-01-01

    Shigella species and Escherichia coli are closely related organisms. Early phenotyping experiments and several recent molecular studies put Shigella within the species E. coli. However, the whole-genome-based, alignment-free and parameter-free CVTree approach shows convincingly that four established Shigella species, Shigella boydii, Shigella sonnei, Shigella felxneri and Shigella dysenteriae, are distinct from E. coli strains, and form sister species to E. coli within the genus Escherichia. ...

  6. Role of Escherichia coli in Biofuel Production

    Science.gov (United States)

    Koppolu, Veerendra; Vasigala, Veneela KR

    2016-01-01

    Increased energy consumption coupled with depleting petroleum reserves and increased greenhouse gas emissions have renewed our interest in generating fuels from renewable energy sources via microbial fermentation. Central to this problem is the choice of microorganism that catalyzes the production of fuels at high volumetric productivity and yield from cheap and abundantly available renewable energy sources. Microorganisms that are metabolically engineered to redirect renewable carbon sources into desired fuel products are contemplated as best choices to obtain high volumetric productivity and yield. Considering the availability of vast knowledge in genomic and metabolic fronts, Escherichia coli is regarded as a primary choice for the production of biofuels. Here, we reviewed the microbial production of liquid biofuels that have the potential to be used either alone or in combination with the present-day fuels. We specifically highlighted the metabolic engineering and synthetic biology approaches used to improve the production of biofuels from E. coli over the past few years. We also discussed the challenges that still exist for the biofuel production from E. coli and their possible solutions. PMID:27441002

  7. Regulation of alcohol fermentation by Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D.P.

    1989-01-01

    The purpose of this project is to elucidate the way in which the fermentative synthesis of ethanol is regulated in the facultative anaerobe Escherichia coli. We are also investigating the control of other genes required for fermentation and anaerobic growth. We have isolated both structural and regulatory mutations affecting the expression of alcohol dehydrogenase, the enzyme responsible for the final step in alcohol synthesis. Some of these regulatory mutations also affect other anaerobically induced genes. The adh gene has been cloned and sequenced. The ADH protein is one of the largest highly expressed proteins in E. coli and requires approximately 2700bp of DNA for its cloning sequence. We have also isolated mutations affecting the fermentative lactate dehydrogenase. In consequence it is now possible to construct E. coli strains defective in the production of any one or more of their normal fermentation products (i.e. formate, acetate, lactate, ethanol and succinate). The factors affecting the ratio of fermentation products are being investigated by in vivo NMR spectroscopy.

  8. [Population genomic researches of Escherichia coli].

    Science.gov (United States)

    Wu, Y R; Yang, R F; Cui, Y J

    2016-06-01

    Population genomics, an interdiscipline of genomics and population genetics, is booming in recent years with the rapid growth number of deciphered genomes and revolutionizes the understanding of bacterial population diversity and evolution dynamics. It also largely improves the prevention and control of infectious disease through providing more accurate genotyping and source-tracing results and more comprehensive characteristics of emerging pathogens. In this review, taking one of the best characterized bacteria, Escherichia coli, as model, we reviewed the phylogenetic relationship across its five major populations (designated A, B1, B2, D and E); and summarized researches on molecular mutation rate, selection signals, and patterns of adaptive evolution. We also described the application of population genomics in responding against large-scale outbreaks of E. coli O157:H7 and E. coli O104:H4. These results indicated that, although being a novel discipline, population genomics has played an important role in deciphering bacterial population structures, exploring evolutionary patterns and combating emerging infectious diseases. PMID:27256740

  9. Role of Escherichia coli in Biofuel Production.

    Science.gov (United States)

    Koppolu, Veerendra; Vasigala, Veneela Kr

    2016-01-01

    Increased energy consumption coupled with depleting petroleum reserves and increased greenhouse gas emissions have renewed our interest in generating fuels from renewable energy sources via microbial fermentation. Central to this problem is the choice of microorganism that catalyzes the production of fuels at high volumetric productivity and yield from cheap and abundantly available renewable energy sources. Microorganisms that are metabolically engineered to redirect renewable carbon sources into desired fuel products are contemplated as best choices to obtain high volumetric productivity and yield. Considering the availability of vast knowledge in genomic and metabolic fronts, Escherichia coli is regarded as a primary choice for the production of biofuels. Here, we reviewed the microbial production of liquid biofuels that have the potential to be used either alone or in combination with the present-day fuels. We specifically highlighted the metabolic engineering and synthetic biology approaches used to improve the production of biofuels from E. coli over the past few years. We also discussed the challenges that still exist for the biofuel production from E. coli and their possible solutions. PMID:27441002

  10. The cobalamin (coenzyme B12) biosynthetic genes of Escherichia coli.

    OpenAIRE

    Lawrence, J. G.; Roth, J R

    1995-01-01

    The enteric bacterium Escherichia coli synthesizes cobalamin (coenzyme B12) only when provided with the complex intermediate cobinamide. Three cobalamin biosynthetic genes have been cloned from Escherichia coli K-12, and their nucleotide sequences have been determined. The three genes form an operon (cob) under the control of several promoters and are induced by cobinamide, a precursor of cobalamin. The cob operon of E. coli comprises the cobU gene, encoding the bifunctional cobinamide kinase...

  11. Diarrheagenic Escherichia coli Markers and Phenotypes among Fecal E. coli Isolates Collected from Nicaraguan Infants ▿

    OpenAIRE

    Reyes, Daniel; Vilchez, Samuel; Paniagua, Margarita; Colque-Navarro, Patricia; Weintraub, Andrej; Möllby, Roland; Kühn, Inger

    2010-01-01

    We analyzed the prevalence of diarrheagenic Escherichia coli (DEC) markers and common phenotypes in 2,164 E. coli isolates from 282 DEC-positive samples. Enteropathogenic E. coli (EPEC) and enteroaggregative E. coli (EAEC) were very diverse and were not correlated with diarrhea. Enterotoxigenic E. coli (ETEC) estA and enterohemorrhagic E. coli (EHEC) belonged to a few phenotypes and were significantly correlated with diarrhea.

  12. Cervical celullitis in broiler chickens for Escherichia coli/
    Celulite cervical em frangos de corte causada por Escherichia coli

    OpenAIRE

    Ivens Gomes Guimarães; Milene Martins Berbel; Marcia Marinho Luzardo; Werner Okano; Claudia Yurika Tamehiro; Benito Guimarães de Brito

    2002-01-01

    In this paper was report the isolation of Escherichia coli in broiler chickens with cellulitis in the cervical region. It was carried through the isolation of E. coli of the lesion of cellulitis from broilers and carried through histopathological examination of skin that had characterized the lesion. Focal ulcerations of epidermis, fibrin in dermis and difuse infiltrated by lymphocytes and heterophils on subcutaneous tissues.Neste trabalho, relata-se o isolamento de Escherichia coli em frango...

  13. Glucose-lactose diauxie in Escherichia coli.

    Science.gov (United States)

    Loomis, W F; Magasanik, B

    1967-04-01

    Growth of Escherichia coli in medium containing glucose, at a concentration insufficient to support full growth, and containing lactose, is diauxic. A mutation in the gene, CR, which determines catabolite repression specific to the lac operon, was found to relieve glucose-lactose but not glucose-maltose diauxie. Furthermore, a high concentration of lactose was shown to overcome diauxie in a CR(+) strain. Studies on the induction of beta-galactosidase by lactose suggested that glucose inhibits induction by 10(-2)m lactose. Preinduction of the lac operon was found to overcome this effect. The ability of glucose to prevent expression of the lac operon by reducing the internal concentration of inducer as well as by catabolite repression is discussed. PMID:5340309

  14. Whole Genome Epidemiological Typing of Escherichia coli

    DEFF Research Database (Denmark)

    Kaas, Rolf Sommer

    is in general expensive and to some extent unreliable. Next generation sequencing has quickly become a tool widely available and has enabled even smaller laboratories to do whole genome sequencing (WGS). Having the entire genome available provides the opportunity to create the ultimate typing method. This Ph......D thesis attempts to take the first steps toward such a method. In Kaas I all publicly available E. coli genomes sequenced (186) are analyzed. 1,702 core genes were found in all genomes. 3,051 genes were found in 95% of the genomes. The pan genome was found to consist of 16,373 genes. The overall phylogeny...... was inferred from the core genome and also set into context of the Escherichia genus. The variance within each gene cluster was calculated in order to compare the variance between genes and possibly identify typing targets for further study. The variance scores calculated was also used to compare the three...

  15. Escherichia coli in chronic inflammatory bowel diseases: An update on adherent invasive Escherichia coli pathogenicity

    Institute of Scientific and Technical Information of China (English)

    Margarita; Martinez-Medina; Librado; Jesus; Garcia-Gil

    2014-01-01

    Escherichia coli(E. coli), and particularly the adherent invasive E. coli(AIEC) pathotype, has been increasingly implicated in the ethiopathogenesis of Crohn’s disease(CD). E. coli strains with similar pathogenic features to AIEC have been associated with other intestinal disorders such as ulcerative colitis, colorectal cancer, and coeliac disease, but AIEC prevalence in these diseases remains largely unexplored. Since AIEC was described one decade ago, substantial progress has been made in deciphering its mechanisms of pathogenicity. However, the molecular bases that characterize the phenotypic properties of this pathotype are still not well resolved. A review of studies focused on E. coli populations in inflammatory bowel disease(IBD) is presented here and we discuss about the putative role of this species on each IBD subtype. Given the relevance of AIEC in CD pathogenesis, we present the latest research findings concerning AIEC host-microbe interactions and pathogenicity. We also review the existing data regarding the prevalence and abundance of AIEC in CD and its association with other intestinal diseases from humans and animals, in order to discuss the AIEC disease- and hostspecificity. Finally, we highlight the fact that dietarycomponents frequently found in industrialized countries may enhance AIEC colonization in the gut, which merits further investigation and the implementation of preventative measures.

  16. Independence of replisomes in Escherichia coli chromosomalreplication

    Energy Technology Data Exchange (ETDEWEB)

    Breier, Adam M.; Weier, Heinz-Ulrich G.; Cozzarelli, Nicholas R.

    2005-03-13

    In Escherichia coli DNA replication is carried out by the coordinated action of the proteins within a replisome. After replication initiation, the two bidirectionally oriented replisomes from a single origin are colocalized into higher-order structures termed replication factories. The factory model postulated that the two replisomes are also functionally coupled. We tested this hypothesis by using DNA combing and whole-genome microarrays. Nascent DNA surrounding oriC in single, combed chromosomes showed instead that one replisome, usually the leftward one, was significantly ahead of the other 70% of the time. We next used microarrays to follow replication throughout the genome by measuring DNA copy number. We found in multiple E. coli strains that the replisomes are independent, with the leftward replisome ahead of the rightward one. The size of the bias was strain-specific, varying from 50 to 130 kb in the array results. When we artificially blocked one replisome, the other continued unabated, again demonstrating independence. We suggest an improved version of the factory model that retains the advantages of threading DNA through colocalized replisomes at about equal rates, but allows the cell flexibility to overcome obstacles encountered during elongation.

  17. Escherichia coli Pathotypes Occupy Distinct Niches in the Mouse Intestine

    OpenAIRE

    Meador, Jessica P.; Caldwell, Matthew E.; Cohen, Paul S.; Conway, Tyrrell

    2014-01-01

    Since the first step of the infection process is colonization of the host, it is important to understand how Escherichia coli pathogens successfully colonize the intestine. We previously showed that enterohemorrhagic O157:H7 strain E. coli EDL933 colonizes a niche in the streptomycin-treated mouse intestine that is distinct from that of human commensal strains, which explains how E. coli EDL933 overcomes colonization resistance imparted by some, but not all, commensal E. coli strains. Here we...

  18. Genomic Comparative Study of Bovine Mastitis Escherichia coli

    OpenAIRE

    Kempf, Florent; Slugocki, Cindy; Blum, Shlomo E.; Leitner, Gabriel; Germon, Pierre

    2016-01-01

    Escherichia coli, one of the main causative agents of bovine mastitis, is responsible for significant losses on dairy farms. In order to better understand the pathogenicity of E. coli mastitis, an accurate characterization of E. coli strains isolated from mastitis cases is required. By using phylogenetic analyses and whole genome comparison of 5 currently available mastitis E. coli genome sequences, we searched for genotypic traits specific for mastitis isolates. Our data confirm that there i...

  19. Pseudosecretion of Escherichia coli chloramphenicol acetyltransferase by Bacillus subtilis.

    OpenAIRE

    Le Grice, S F; Gentz, R; Bannwarth, W; Kocher, H. P.

    1987-01-01

    Bacillus subtilis harboring the vector 25RBSII secrets an Escherichia coli-derived chloramphenicol acetyltransferase into culture supernatants. The secreted enzyme lacks 18 amino acids; these are removed externally rather than during secretion.

  20. Role of recBC nuclease in Escherichia coli transformation.

    OpenAIRE

    Hoekstra, W P; Bergmans, J E; Zuidweg, E.M.

    1980-01-01

    In Escherichia coli transformation with linear donor deoxyribonucleic acid, the recBC pathway is functional, but genetic analysis shows that the recBC nuclease is deleterious to linear deoxyribonucleic acid.

  1. Heat-stable enterotoxins from Escherichia coli P16.

    OpenAIRE

    Burgess, M N; Mullan, N A; Newsome, P.M.

    1980-01-01

    Escherichia coli P16 infant mouse active heat-stable enterotoxin may be fractionated into two distinct active moieties by ion-exchange chromatography, Sephadex G-25 chromatography, and isoelectric focusing.

  2. A DNA structural atlas for Escherichia coli.

    Science.gov (United States)

    Pedersen, A G; Jensen, L J; Brunak, S; Staerfeldt, H H; Ussery, D W

    2000-06-16

    We have performed a computational analysis of DNA structural features in 18 fully sequenced prokaryotic genomes using models for DNA curvature, DNA flexibility, and DNA stability. The structural values that are computed for the Escherichia coli chromosome are significantly different from (and generally more extreme than) that expected from the nucleotide composition. To aid this analysis, we have constructed tools that plot structural measures for all positions in a long DNA sequence (e.g. an entire chromosome) in the form of color-coded wheels (http://www.cbs.dtu. dk/services/GenomeAtlas/). We find that these "structural atlases" are useful for the discovery of interesting features that may then be investigated in more depth using statistical methods. From investigation of the E. coli structural atlas, we discovered a genome-wide trend, where an extended region encompassing the terminus displays a high of level curvature, a low level of flexibility, and a low degree of helix stability. The same situation is found in the distantly related Gram-positive bacterium Bacillus subtilis, suggesting that the phenomenon is biologically relevant. Based on a search for long DNA segments where all the independent structural measures agree, we have found a set of 20 regions with identical and very extreme structural properties. Due to their strong inherent curvature, we suggest that these may function as topological domain boundaries by efficiently organizing plectonemically supercoiled DNA. Interestingly, we find that in practically all the investigated eubacterial and archaeal genomes, there is a trend for promoter DNA being more curved, less flexible, and less stable than DNA in coding regions and in intergenic DNA without promoters. This trend is present regardless of the absolute levels of the structural parameters, and we suggest that this may be related to the requirement for helix unwinding during initiation of transcription, or perhaps to the previously observed

  3. The Escherichia coli divisome: born to divide.

    Science.gov (United States)

    Natale, Paolo; Pazos, Manuel; Vicente, Miguel

    2013-12-01

    Septation in Escherichia coli involves complex molecular mechanisms that contribute to the accuracy of bacterial division. The proto-ring, a complex made up by the FtsZ, FtsA and ZipA proteins, forms at the beginning of the process and directs the assembly of the full divisome. Central to this complex is the FtsZ protein, a GTPase able to assemble into a ring-like structure that responds to several modulatory inputs including mechanisms to position the septum at midcell. The connection with the cell wall synthesising machinery stabilizes the constriction of the cytoplasmic membrane. Although a substantial amount of evidence supports this description, many details on how individual divisome elements are structured or how they function are subjected to controversial interpretations. We discuss these discrepancies arising from incomplete data and from technical difficulties imposed by the small size of bacteria. Future work, including more powerful imaging and reconstruction technologies, will help to clarify the missing details on the architecture and function of the bacterial division machinery. PMID:23962168

  4. Completion of DNA replication in Escherichia coli

    Science.gov (United States)

    Wendel, Brian M.; Courcelle, Charmain T.; Courcelle, Justin

    2014-01-01

    The mechanism by which cells recognize and complete replicated regions at their precise doubling point must be remarkably efficient, occurring thousands of times per cell division along the chromosomes of humans. However, this process remains poorly understood. Here we show that, in Escherichia coli, the completion of replication involves an enzymatic system that effectively counts pairs and limits cellular replication to its doubling point by allowing converging replication forks to transiently continue through the doubling point before the excess, over-replicated regions are incised, resected, and joined. Completion requires RecBCD and involves several proteins associated with repairing double-strand breaks including, ExoI, SbcDC, and RecG. However, unlike double-strand break repair, completion occurs independently of homologous recombination and RecA. In some bacterial viruses, the completion mechanism is specifically targeted for inactivation to allow over-replication to occur during lytic replication. The results suggest that a primary cause of genomic instabilities in many double-strand-break-repair mutants arises from an impaired ability to complete replication, independent from DNA damage. PMID:25368150

  5. Expression of Treponema pallidum antigens in Escherichia coli K-12.

    OpenAIRE

    Stamm, L V; Folds, J D; Bassford, P J

    1982-01-01

    A colony bank of recombinant plasmids harboring Treponema pallidum DNA inserts has been established in Escherichia coli K-12. By using an in situ immunoassay, we identified four E. coli clones that expressed T. pallidum antigens. Thus, recombinant DNA technology may provide powerful new tools for studying the pathogenesis of T. pallidum infection.

  6. PCR-ELISA detection of Escherichia coli in milk

    OpenAIRE

    Doyle, Sean; Daly, Paul; Collier, T.

    2002-01-01

    Aims: The purpose of this study was to develop a reliable molecular procedure for the detection of Escherichia coli in milk. Methods and Results: Robust and expeditious DNA extraction and PCR techniques were evaluated using Enzyme-Linked Immunosorbent Assay (ELISA) detection of biotin-labelled amplicons to facilitate optimal detection of E. coli DNA. Conclusions: It was found that 5 E. coli colony-forming units (cfu) could be detected per PCR reaction using the PCR-ELISA sys...

  7. Draft Genome Sequence of Uropathogenic Escherichia coli Strain NB8.

    Science.gov (United States)

    Weng, Xing-Bei; Mi, Zu-Huang; Wang, Chun-Xin; Zhu, Jian-Ming

    2016-01-01

    Escherichia coli NB8 is a clinical pyelonephritis isolate. Here, we report the draft genome sequence of uropathogenic E. coli NB8, which contains drug resistance genes encoding resistance to beta-lactams, aminoglycosides, quinolones, macrolides, colistin, sulfonamide-trimethoprim, and tetracycline. NB8 infects the kidney and bladder, making it an important tool for studying E. coli pathogenesis. PMID:27609920

  8. Findings of Escherichia coli and Enterococcus spp. in homemade cheese

    Directory of Open Access Journals (Sweden)

    Tambur Zoran

    2007-01-01

    Full Text Available During the period from February until March 2004, 108 samples of soft cheese originating from markets of Pancevo, Subotica and Belgrade were examined. Microbiological analyses of the cheese samples to the presence of Escherichia coli was performed using methods described in the Regulations on methods for performing microbiological analyses and super analyses of consumer articles, while the presence of bacteria Enteroccocus spp. was performed on the dexter agar. From 108 samples of soft cheese from the territories of Pancevo, Belgrade and Subotica were isolated: Enterococcus spp. from 96% and Escherichia coli from 69%, cheese samples. Verocytotoxic E.coli was not isolated from any of the taken cheese samples.

  9. Classification of the bacteria E. coli and S. aureus by spectroscopy technique laser induced plasma

    International Nuclear Information System (INIS)

    The Laser Induced Breakdown Spectroscopy (LBS) is a technique of compositional analysis, which uses a laser pulse in order to vaporize from nanogram to microgram amount of any material, and thermally excites the material vaporizing in a short-life plasma. the technique also it has advantages among which is that not require pretreatment of the sample, easy and quick operation, free of chemicals during the process and does not modify the state of the sample, it can be solid, liquid, spray or gas. Due to the growing demand to identify bacteria in a fast, reliably and accurately way, in this work it has been proposed to use the LIBS technique and a classifier clustering to identify the Staphylococcus aureus and Escherichia coli bacteria. As excitation source a Q:Switch multipulse laser is used, which favors the emission intensity. The results show a clear classification of these two bacteria strains. (Author)

  10. The versatile strategies of Escherichia coli pathotypes: a mini review

    Directory of Open Access Journals (Sweden)

    C. P. Sousa

    2006-01-01

    Full Text Available The widespread species Escherichia coli includes a broad variety of different types, ranging from highly pathogenic strains to avirulent isolates. Few microorganisms are as versatile as E. coli. Pathogenic strains remain a leading cause of severe and persistent infant diarrhea in developing countries. They may be limited to colonization of a mucosal surface or can disseminate throughout the body and have been implicated in urinary tract infection, sepsis/meningitis and gastrointestinal infection. The human gastrointestinal tract is susceptible to diarrheagenic E. coli infections. Escherichia coli have effectively managed to subvert the host cytoskeleton for their own purposes causing substantial diarrheal disease, a major public health problem worldwide. This review deals with the different strategies regarding E. coli as a pathogen and the virulence traits of its pathotypes highlighting the species as a commensal, opportunistic and specialized pathogen.

  11. ESBL-Producing Escherichia coli

    DEFF Research Database (Denmark)

    Hertz, Frederik Boetius

    Urinary tract infection (UTI) is one the most common bacterial infections and is regularly treated in primary health care. The most common cause of UTI is extraintestinal pathogenic Escherichia coli (ExPEC) already present in the intestinal microflora, often as the dominating strain. Resistance in...... E.coli is increasing and especially isolates producing Extended-Spectrum Beta-Lactamases (ESBL) have been reported worldwide. Treatment of UTI is usually initiated by the general practitioners and a significant proportion of clinical isolates are now resistant to first line antibiotics. The global...... dissemination of resistant E.coli has in particular been driven by the spread of a few specific E.coli-lineages and it seems that there is a difference between the sequence types found among resistant E.coli, ESBL-producing E.coli and antibiotic susceptible E.coli. The overall objectives of this thesis were to...

  12. Is Escherichia coli urinary tract infection a zoonosis?

    DEFF Research Database (Denmark)

    Jacobsen, L.; Garneau, P.; Bruant, G.;

    2012-01-01

    Recently, it has been suggested that the Escherichia coli causing urinary tract infection (UTI) may come from meat and animals. The purpose was to investigate if a clonal link existed between E. coli from animals, meat and UTI patients. Twenty-two geographically and temporally matched B2 E. coli...... and kidney cultures. Further, isolates with the same gene profile also yielded similar bacterial counts in urine, bladder and kidneys. This study showed a clonal link between E. coli from meat and humans, providing solid evidence that UTI is zoonosis. The close relationship between community...

  13. Survey of microbial contamination and characterization of Escherichia coli in kiwifruit orchards in Shaanxi, China, 2013.

    Science.gov (United States)

    Feng, Yuqing; Yang, Qinnan; Wang, Lingfang; Li, Guanghui; Lv, Xiaoying; Han, Qi'an; Liu, Xiaobo; Xia, Xiaodong

    2015-10-01

    The aim of the study was to survey three foodborne pathogens in kiwifruit orchards as a continuous monitoring program. A total of 193 samples were collected from 11 kiwifruit orchards in Shaanxi province in October 2013. Among the 193 samples, 68 Escherichia coli isolates were recovered, while no Staphylococcus aureus and Salmonella was recovered. All E. coli isolates were characterized by antimicrobial susceptibility testing, detection of virulence genes, and the ability to produce biofilm formation. The isolates were further examined by random amplified polymorphic DNA (RAPD) analysis. E. coli isolates displayed resistance most frequently to tetracycline (48.5%). Two E. coli isolates (2.9%) were positive for the eae gene (the intimin gene). All E. coli isolates lacked the ability to make biofilm formation. Multilocus sequence typing analysis demonstrated that one isolate in kiwifruit orchards shared the same sequence type with a human clinical isolate. RAPD results showed a close relationship among E. coli isolates from fresh fruit, fallen fruit, soil, air, and irrigation water. This study could provide a further understanding of microbial contamination in kiwifruit orchards based on our previous study and help growers take appropriate measures for prevention. PMID:26267480

  14. Outbreaks of virulent diarrheagenic Escherichia coli - are we in control?

    OpenAIRE

    Werber Dirk; Krause Gérard; Frank Christina; Fruth Angelika; Flieger Antje; Mielke Martin; Schaade Lars; Stark Klaus

    2012-01-01

    Abstract Shiga toxin-producing Escherichia coli (STEC) are the most virulent diarrheagenic E. coli known to date. They can be spread with alarming ease via food as exemplified by a large sprout-borne outbreak of STEC O104:H4 in 2011 that was centered in northern Germany and affected several countries. Effective control of such outbreaks is an important public health task and necessitates early outbreak detection, fast identification of the outbreak vehicle and immediate removal of the suspect...

  15. Outbreaks of virulent diarrheagenic Escherichia coli - are we in control?

    OpenAIRE

    Werber, Dirk; Krause, Gérard; Frank, Christina; Fruth, Angelika; Mielke, Martin; Schaade, Lars; Stark, Klaus

    2012-01-01

    Shiga toxin-producing Escherichia coli (STEC) are the most virulent diarrheagenic E. coli known to date. They can be spread with alarming ease via food as exemplified by a large sprout-borne outbreak of STEC O104:H4 in 2011 that was centered in northern Germany and affected several countries. Effective control of such outbreaks is an important public health task and necessitates early outbreak detection, fast identification of the outbreak vehicle and immediate removal of the suspected fo...

  16. Fundamental study of recombination and recombineering in Escherichia coli

    OpenAIRE

    Sun, Xiaohang; Huang, Yang

    2008-01-01

    Recombination and recombineering systems have been used in Escherichia coli to recombinant DNA sequences. With endonuclease and DNA lipase the bacterial plasmid and target DNA fragment can bind together and recombinant for a new DNA sequences. Red Proteins have been used in recombineering system to perform the function as the enzymes in recombination system, and faster and easier than the other way of recombinant new DNA sequences in E.coli. In this report we get to know the pr...

  17. Differential expression of the Escherichia coli autoaggregation factor antigen 43

    DEFF Research Database (Denmark)

    Schembri, Mark; Hjerrild, Louise; Gjermansen, Morten;

    2003-01-01

    Antigen 43 (Ag43) is a self-recognizing surface adhesin found in most Escherichia coli strains. Due to its excellent cell-to-cell aggregation characteristics, Ag43 expression confers clumping and fluffing of cells and promotes biofilm formation. Ag43 expression is repressed by the cellular redox......-forming potential of E. coli. Finally, we demonstrated that Ag43-mediated cell aggregation confers significant protection against hydrogen peroxide killing....

  18. Escherichia coli and Community-acquired Gastroenteritis, Melbourne, Australia

    OpenAIRE

    Robins-Browne, Roy M.; Bordun, Anne-Marie; Tauschek, Marija; Bennett-Wood, Vicki R.; Russell, Jacinta; Oppedisano, Frances; Lister, Nicole A.; Bettelheim, Karl A.; Fairley, Christopher K.; Sinclair, Martha I; Hellard, Margaret E

    2004-01-01

    As part of a study to determine the effects of water filtration on the incidence of community-acquired gastroenteritis in Melbourne, Australia, we examined fecal samples from patients with gastroenteritis and asymptomatic persons for diarrheagenic strains of Escherichia coli. Atypical strains of enteropathogenic E. coli (EPEC) were the most frequently identified pathogens of all bacterial, viral, and parasitic agents in patients with gastroenteritis. Moreover, atypical EPEC were more common i...

  19. Recombinant Production of Human Interleukin 6 in Escherichia coli

    OpenAIRE

    Henrik Nausch; Jana Huckauf; Roswitha Koslowski; Udo Meyer; Inge Broer; Heike Mikschofsky

    2013-01-01

    In this study, we compared basic expression approaches for the efficient expression of bioactive recombinant human interleukin-6 (IL6), as an example for a difficult-to-express protein. We tested these approaches in a laboratory scale in order to pioneer the commercial production of this protein in Escherichia coli (E. coli). Among the various strategies, which were tested under Research and Development (R&D) conditions, aggregation-prone IL6 was solubilized most effectively by co-expressing ...

  20. Survival of Escherichia coli and Salmonella spp. in estuarine environments.

    OpenAIRE

    Rhodes, M W; Kator, H.

    1988-01-01

    Survival of Escherichia coli and Salmonella spp. in estuarine waters was compared over a variety of seasonal temperatures during in situ exposure in diffusion chambers. Sublethal stress was measured by both selective-versus-resuscitative enumeration procedures and an electrochemical detection method. E. coli and Salmonella spp. test suspensions, prepared to minimize sublethal injury, were exposed in a shallow tidal creek and at a site 7.1 km further downriver. Bacterial die-off and sublethal ...

  1. Role of granulocytes and monocytes in experimental Escherichia coli endocarditis.

    OpenAIRE

    Meddens, M J; Thompson, J.; Bauer, W C; van Furth, R

    1984-01-01

    The role of granulocytes and monocytes during the induction and course of Escherichia coli endocarditis was investigated in rabbits by selectively depleting monocytes from the circulation with the drug VP16-213 and granulocytes and monocytes with nitrogen mustard. For induction, the number of E. coli needed to infect the vegetations in 50% of the rabbits was significantly lower in rabbits with combined granulocytopenia and monocytopenia than in those with selective monocytopenia or in control...

  2. Metabolic and Transcriptional Response to Cofactor Perturbations in Escherichia coli

    DEFF Research Database (Denmark)

    Holm, Anders Koefoed; Blank, L.M.; Oldiges, M.;

    2010-01-01

    Metabolic cofactors such as NADH and ATP play important roles in a large number of cellular reactions, and it is of great interest to dissect the role of these cofactors in different aspects of metabolism. Toward this goal, we overexpressed NADH oxidase and the soluble F1-ATPase in Escherichia coli...... general understanding of redox and energy metabolism and should help in developing metabolic engineering strategies in E. coli....

  3. Dissecting the roles of Escherichia coli hydrogenases in biohydrogen production

    OpenAIRE

    Redwood, MD; Mikheenko, IP; Sargent, F.; Macaskie, LE

    2008-01-01

    Escherichia coli can perform at least two modes of anaerobic hydrogen metabolism and expresses at least two types of hydrogenase activity. Respiratory hydrogen oxidation is catalysed by two ‘uptake’ hydrogenase isoenzymes, hydrogenase -1 and -2 (Hyd-1 and -2), and fermentative hydrogen production is catalysed by Hyd-3. Harnessing and enhancing the metabolic capability of E. coli to perform anaerobic mixed-acid fermentation is therefore an attractive approach for bio-hydrogen production ...

  4. Cervical celullitis in broiler chickens for Escherichia coli/ Celulite cervical em frangos de corte causada por Escherichia coli

    Directory of Open Access Journals (Sweden)

    Ivens Gomes Guimarães

    2002-05-01

    Full Text Available In this paper was report the isolation of Escherichia coli in broiler chickens with cellulitis in the cervical region. It was carried through the isolation of E. coli of the lesion of cellulitis from broilers and carried through histopathological examination of skin that had characterized the lesion. Focal ulcerations of epidermis, fibrin in dermis and difuse infiltrated by lymphocytes and heterophils on subcutaneous tissues.Neste trabalho, relata-se o isolamento de Escherichia coli em frangos de corte apresentando lesão de celulite na região cervical. Foi realizado o isolamento de E. coli da lesão de celulite e realizado exames histopatológicos que caracterizaram a lesão. Na epiderme foram verificadas lesões ulcerativas, presença de fibrina na derme e infiltração difusa de linfócitos e heterófilos no tecido subcutâneo.

  5. DAYA HAMBAT FRAKSINASI EKSTRAK SEMBUNG DELAN (SPHAERANTUS INDICUS L) TERHADAP BAKTERI ESCHERICIA COLI DAN STAPHYLOCOCCUS AUREUS

    OpenAIRE

    IDA BAGUS GEDE DARMAYASA

    2008-01-01

    A research entitled "Inhibitid activity of plant fractination extract of Sembung Delan (Sphaeranthus indicus L.) to Eschericia coli and Staphylococus aureus bacterial was carried aut to find the active of plant extract that responsible for bactericidal agent. This research used absorbance disc method to determine inhibitid fractionation extratc of Sembung Delan to growth of Eschericia coli and Staphylococus aureus bacterial. Results of this study showed that the crude extract of Sembung Delan...

  6. Inactivation of Escherichia Coli in Orange Juice Using Ozone

    OpenAIRE

    Patil, Sonal; Bourke, Paula; Frias, Jesus Maria; Tiwari, Brijesh; Cullen, Patrick

    2009-01-01

    This research investigated the efficacy of gaseous ozone for the inactivation of Escherichia coli ATCC 25922 and NCTC 12900 strains in orange juice. Orange juice inoculated with E. coli (106 CFU mL-1) as a challenge microorganism was treated with ozone at 75-78µg mL-1 for different time periods (0-18 min). The efficacy of ozone for inactivation of both strains of E. coli was evaluated as a function of different juice types: model orange juice, fresh unfiltered juice, juice without pulp, and j...

  7. Escherichia coli O26 IN RAW BUFFALO MILK: PRELIMINARY RESULTS

    Directory of Open Access Journals (Sweden)

    A. Rella

    2013-02-01

    Full Text Available Escherichia coli O26 is considered to be one of the most important food-borne pathogen. In this study, 120 buffalo milk samples collected in Lazio and in Apulia regions were tested for the presence of E. coli O26. One buffalo milk sample (0,8% tested positive for E. coli O26; the isolate was positive at the verocytotoxicity test and it showed resistance properties to different antimicrobial classes. These preliminary results highlight the need to monitor the foods of animal origin used for production and eaten by a wide range of persons, respect VTEC organism.

  8. Protein abundance profiling of the Escherichia coli cytosol

    DEFF Research Database (Denmark)

    Ishihama, Y.; Schmidt, T.; Rappsilber, J.;

    2008-01-01

    sample. Using a combination of LC-MS/MS approaches with protein and peptide fractionation steps we identified 1103 proteins from the cytosolic fraction of the Escherichia coli strain MC4100. A measure of abundance is presented for each of the identified proteins, based on the recently developed em...... between protein and mRNA abundance in E. coli cells. Conclusion: Abundance measurements for more than 1000 E. coli proteins presented in this work represent the most complete study of protein abundance in a bacterial cell so far. We show significant associations between the abundance of a protein and its...

  9. YeeO from Escherichia coli exports flavins.

    Science.gov (United States)

    McAnulty, Michael J; Wood, Thomas K

    2014-01-01

    Multidrug and toxic compound extrusion (MATE) proteins help maintain cellular homeostasis by secreting metabolic wastes. Flavins may occur as cellular waste products, with their production and secretion providing potential benefit for industrial applications related to biofuel cells. Here we find that MATE protein YeeO from Escherichia coli exports both flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). Significant amounts of flavins were trapped intracellularly when YeeO was produced indicating transport limits secretion of flavins. Wild-type E. coli secreted 3 flavins (riboflavin, FMN, and FAD), so E. coli likely produces additional flavin transporters. PMID:25482085

  10. An integrated database to support research on Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Baehr, A.; Dunham, G.; Matsuda, Hideo; Michaels, G.; Taylor, R.; Overbeek, R.; Rudd, K.E. [National Inst. of Mental Health, Bethesda, MD (United States); Ginsburg, A.; Joerg, D.; Kazic, T. [Washington Univ., St. Louis, MO (United States). Dept. of Genetics; Hagstrom, R.; Zawada, D. [Argonne National Lab., IL (United States); Smith, C.; Yoshida, Kaoru [Lawrence Berkeley Lab., CA (United States)

    1992-01-01

    We have used logic programming to design and implement a prototype database of genomic information for the model bacterial organism Escherichia coli. This report presents the fundamental database primitives that can be used to access and manipulate data relating to the E. coli genome. The present system, combined with a tutorial manual, provides immediate access to the integrated knowledge base for E. coli chromosome data. It also serves as the foundation for development of more user-friendly interfaces that have the same retrieval power and high-level tools to analyze complex chromosome organization.

  11. Molecular Characterization of Diarrheagenic Escherichia coli from Libya

    Science.gov (United States)

    Ali, Mostafa Mohamed M.; Mohamed, Zienat Kamel; Klena, John D.; Ahmed, Salwa Fouad; Moussa, Tarek A. A.; Ghenghesh, Khalifa Sifaw

    2012-01-01

    Diarrheagenic Escherichia coli (DEC) are important enteric pathogens that cause a wide variety of gastrointestinal diseases, particularly in children. Escherichia coli isolates cultured from 243 diarrheal stool samples obtained from Libyan children and 50 water samples were screened by polymerase chain reaction (PCR) for genes characteristic of enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enterohemorrhagic E. coli (EHEC), and enteroinvasive E. coli (EIEC). The DEC were detected in 21 (8.6%) children with diarrhea; 10 (4.1%) cases were identified as EAEC, 3 (1.2%) as EPEC, and 8 (3.3%) were ETEC; EHEC, and EIEC were not detected. All DEC were grouped phylogenetically by PCR with the majority (> 70%) identified as phylogenetic groups A and B1. The EAEC isolates were also tested for eight genes associated with virulence using PCR. Multi-virulence (≥ 3 virulence factors) was found in 50% of EAEC isolates. Isolated EAEC possessed different virulence traits and belonged to different phylogenetic groups indicating their heterogeneity. PMID:22556089

  12. Recent Sensitivity Pattern of Escherichia Coli in Urinary Tract Infection

    Directory of Open Access Journals (Sweden)

    R Nalini

    2014-06-01

    Full Text Available The objective of the study is to assess the recent sensitivity pattern of Escherichia coli in Urinary tract infection (UTI.Widespread use of antibiotics has led to the emergence of resistant microorganisms. As the antibiotic sensitivity patterns of the microorganisms are frequently changing, this retrospective analysis was designed to assess the recent antibiotic sensitivity pattern of Escherichia coli (E.coli in urinary tract infection among the human population. Details of 412 urine culture positive reports for E.coli and their antibiotic sensitivity pattern pertaining to the study period of 12months from June 2012 to May 2013 were collected from Central Microbiology Laboratory of Tirunelveli Medical College and the results were statistically analysed. The antibiotics tested for sensitivity were Amikacin, Gentamycin, Ciprofloxacin, Cotrimoxazole, Nitrofurantoin, Ceftazidime, Ceftriaxone and Cefotaxime. The sensitivity pattern of E.coli to antibiotics in UTI were Nitrofurantoin (85.19%, Amikacin (66.50%, Co-trimoxazole(31.31%, Gentamycin (26.90%, Ceftazidime (26.69% ,Ciprofloxacin (22.57%, Cefotaxime (22.30%, Ceftriaxone (17.47%. The study highlighted the re-emergence of E. coli sensitive to Nitrofurantoin and marked resistance of E.coli to Aminoglycoside and third generation Cephalosporins.

  13. Carbon and energy metabolism of atp mutants of Escherichia coli

    DEFF Research Database (Denmark)

    Jensen, Peter Ruhdal; Michelsen, Ole

    1992-01-01

    The membrane-bound H+-ATPase plays a key role in free-energy transduction of biological systems. We report how the carbon and energy metabolism of Escherichia coli changes in response to deletion of the atp operon that encodes this enzyme. Compared with the isogenic wild-type strain, the growth...

  14. Genetic Basis of Minicell Formation in Escherichia coli K-12

    OpenAIRE

    1984-01-01

    Hfr- and P1-mediated genetic transfer experiments failed to confirm the presence of a " minA " gene in Escherichia coli K-12, leading to the conclusion that mutation at a single locus, the minB locus, is sufficient to cause minicell production in this species.

  15. Antibiotic treatment of verocytotoxin-producing Escherichia coli (VTEC) infection

    DEFF Research Database (Denmark)

    Agger, Morten; Scheutz, Flemming; Villumsen, Steen; Mølbak, Kåre; Petersen, Andreas Munk

    2015-01-01

    OBJECTIVES: A consensus has existed on not to treat verocytotoxin-producing Escherichia coli (VTEC)-infected individuals with antibiotics because of possible subsequent increased risk of developing haemolytic uraemic syndrome (HUS). The aim of this systematic review is to clarify the risk...

  16. Escherichia coli. A sanitary methodology for faecal water pollution tests

    International Nuclear Information System (INIS)

    Among the traditional indictors of faecal water pollution, Escherichia coli has shown to fit better with the definition of indicator organism. Till now its recovery has been time-consuming and needs confirmation tests. In this report more rapid and direct methods, based on enzymatic reactions, are presented

  17. DNA supercoiling depends on the phosphorylation potential in Escherichia coli

    DEFF Research Database (Denmark)

    Van Workum, M.; van Dooren, S.J.M; Oldenburg, N;

    1996-01-01

    ATP/ADP ratios were varied in different ways and the degree of negative supercoiling was determined in Escherichia coli. Independent of whether the ATP/ADP ratio was reduced by a shift to anaerobic conditions, by addition of protonophore (dinitrophenol) or by potassium cyanide addition, DNA...

  18. Chromosomal replication incompatibility in Dam methyltransferase deficient Escherichia coli cells

    DEFF Research Database (Denmark)

    Freiesleben, Ulrik Von

    1996-01-01

    Dam methyltransferase deficient Escherichia coli cells containing minichromosomes were constructed. Free plasmid DNA could not be detected in these cells and the minichromosomes were found to be integrated in multiple copies in the origin of replication (oriC) region of the host chromosome. The...

  19. Escherichia coli and other Enterobacteriaceae: Food poisoning and health effects

    Science.gov (United States)

    The family Enterobactericeae consists of rod-shaped, Gram-negative, facultatively anaerobic, non-spore forming bacteria and also includes the food-borne pathogens, Cronobacter spp., Escherichia coli, Salmonella enterica, Shigella spp., and Yersinia spp. Illness caused by these pathogens is acquired...

  20. Multidrug-Resistant Escherichia coli in Bovine Animals, Europe.

    Science.gov (United States)

    Brennan, Evan; Martins, Marta; McCusker, Matthew P; Wang, Juan; Alves, Bruno Martins; Hurley, Daniel; El Garch, Farid; Woehrlé, Frédérique; Miossec, Christine; McGrath, Leisha; Srikumar, Shabarinath; Wall, Patrick; Fanning, Séamus

    2016-09-01

    Of 150 Escherichia coli strains we cultured from specimens taken from cattle in Europe, 3 had elevated MICs against colistin. We assessed all 3 strains for the presence of the plasmid-mediated mcr-1 gene and identified 1 isolate as mcr-1-positive and co-resistant to β-lactam, florfenicol, and fluoroquinolone antimicrobial compounds. PMID:27533105

  1. Differential expression of the Escherichia coli autoaggregation factor antigen 43

    DEFF Research Database (Denmark)

    Schembri, Mark; Hjerrild, Louise; Gjermansen, Morten; Klemm, Per

    2003-01-01

    Antigen 43 (Ag43) is a self-recognizing surface adhesin found in most Escherichia coli strains. Due to its excellent cell-to-cell aggregation characteristics, Ag43 expression confers clumping and fluffing of cells and promotes biofilm formation. Ag43 expression is repressed by the cellular redox...

  2. Escherichia coli and virus isolated from ''sticky kits''

    DEFF Research Database (Denmark)

    Jørgensen, M.; Scheutz, F.; Strandbygaard, Bertel

    1996-01-01

    A total of 121 Escherichia coli strains isolated from 3-week-old mink kits were serotyped and examined for virulence factors. 56 strains were isolated from healthy kits while 65 were from ''sticky kits''. Among these, 34 different serotypes were detected. No difference in serotypes or the presenc...

  3. Dynamics of Escherichia coli Chromosome Segregation during Multifork Replication

    DEFF Research Database (Denmark)

    Nielsen, Henrik Jørck; Youngren, Brenda; Hansen, Flemming G.;

    2007-01-01

    Slowly growing Escherichia coli cells have a simple cell cycle, with replication and progressive segregation of the chromosome completed before cell division. In rapidly growing cells, initiation of replication occurs before the previous replication rounds are complete. At cell division, the...

  4. Molecular characterization of the Escherichia coli asymptomatic bacteriuria strain 83972

    DEFF Research Database (Denmark)

    Klemm, Per; Hancock, Viktoria; Ulett, G.C.;

    2006-01-01

    Escherichia coli 83972 is a clinical asymptomatia bacteriuric isolate that is able to colonize the human urinary bladder without inducing an immune response. Here we demonstrate that one of the mechanisms by which this strain has become attenuated is through the mutation of its genes encoding type...

  5. Aging in Escherichia coli: stochasticity, individual heterogeneity and mortality plateaus

    DEFF Research Database (Denmark)

    Steiner, Uli

    2014-01-01

    suggested to be involved in aging and senescence, but no mechanism or factor has been unambiguously identified. Here, we report on surprising patterns of aging and senescence from isogenic individual Escherichia coli bacteria grown under identical environmental conditions in a microfluidic device. Such...

  6. FimH-mediated autoaggregation of Escherichia coli

    DEFF Research Database (Denmark)

    Schembri, Mark; Christiansen, G.; Klemm, Per

    2001-01-01

    Autoaggregation is a phenomenon thought to contribute to colonization of mammalian hosts by pathogenic bacteria. Type 1 fimbriae are surface organelles of Escherichia coli that mediate D-mannose-sensitive binding to various host surfaces. This binding is conferred by the minor fimbrial component ...

  7. Binding of Divalent Magnesium by Escherichia coli Phosphoribosyl Diphosphate Synthetase

    DEFF Research Database (Denmark)

    Willemoës, Martin; Hove-Jensen, Bjarne

    1997-01-01

    The mechanism of binding of the substrates MgATP and ribose 5-phosphate as well as Mg2+ to the enzyme 5-phospho-d-ribosyl a-1-diphosphate synthetase from Escherichia coli has been analyzed. By use of the competive inhibitors of ATP and ribose 5-phosphate binding, a,ß-methylene ATP and (+)-1-a,2-a...

  8. Binding of divalent magnesium by Escherichia coli phosphoribosyl diphosphate synthetase

    DEFF Research Database (Denmark)

    Willemoës, Martin; Hove-Jensen, Bjarne

    1997-01-01

    The mechanism of binding of the substrates Mg x ATP and ribose 5-phosphate as well as Mg2+ to the enzyme 5-phospho-D-ribosyl (alpha-1-diphosphate synthetase from Escherichia coli has been analyzed. By use of the competive inhibitors of ATP and ribose 5-phosphate binding, alpha,beta-methylene ATP ...

  9. Cytokine response to Escherichia coli in gnotobiotic pigs

    Czech Academy of Sciences Publication Activity Database

    Šplíchal, Igor; Šplíchalová, Alla; Trebichavský, Ilja

    2008-01-01

    Roč. 53, č. 2 (2008), s. 161-164. ISSN 0015-5632 R&D Projects: GA ČR GA523/05/0249 Institutional research plan: CEZ:AV0Z50200510 Keywords : germ-free pigs * escherichia coli * cytokine response Subject RIV: EE - Microbiology, Virology Impact factor: 1.172, year: 2008

  10. Phylogenetic Group Determination of Escherichia coli Isolated from Animals Samples

    Directory of Open Access Journals (Sweden)

    Fernanda Morcatti Coura

    2015-01-01

    Full Text Available This study analyzes the occurrence and distribution of phylogenetic groups of 391 strains of Escherichia coli isolated from poultry, cattle, and water buffalo. The frequency of the phylogroups was A = 19%, B1 = 57%, B2 = 2.3%, C = 4.6%, D = 2.8%, E = 11%, and F = 3.3%. Phylogroups A (P<0.001 and F (P=0.018 were associated with E. coli strains isolated from poultry, phylogroups B1 (P<0.001 and E (P=0.002 were associated with E. coli isolated from cattle, and phylogroups B2 (P=0.003 and D (P=0.017 were associated with E. coli isolated from water buffalo. This report demonstrated that some phylogroups are associated with the host analyzed and the results provide knowledge of the phylogenetic composition of E. coli from domestic animals.

  11. Phylogenetic Group Determination of Escherichia coli Isolated from Animals Samples

    Science.gov (United States)

    Morcatti Coura, Fernanda; Diniz, Soraia de Araújo; Silva, Marcos Xavier; Mussi, Jamili Maria Suhet; Barbosa, Silvia Minharro; Lage, Andrey Pereira; Heinemann, Marcos Bryan

    2015-01-01

    This study analyzes the occurrence and distribution of phylogenetic groups of 391 strains of Escherichia coli isolated from poultry, cattle, and water buffalo. The frequency of the phylogroups was A = 19%, B1 = 57%, B2 = 2.3%, C = 4.6%, D = 2.8%, E = 11%, and F = 3.3%. Phylogroups A (P < 0.001) and F (P = 0.018) were associated with E. coli strains isolated from poultry, phylogroups B1 (P < 0.001) and E (P = 0.002) were associated with E. coli isolated from cattle, and phylogroups B2 (P = 0.003) and D (P = 0.017) were associated with E. coli isolated from water buffalo. This report demonstrated that some phylogroups are associated with the host analyzed and the results provide knowledge of the phylogenetic composition of E. coli from domestic animals. PMID:26421310

  12. Occurrence of pathogenic and faecal Escherichia coli in layer hens

    Directory of Open Access Journals (Sweden)

    Silvia Tagliabue

    2010-01-01

    Full Text Available A total of 117 Escherichia coli from colibacillosis affected (APEC and clinically healthy birds (AFEC were serotyped and tested for the presence of virulence genes: iss, tsh, cva. A total of 54.5% E. Coli were typeable and 15 different serogroups were identified. The most common serogroups among APEC strains were O78, O2 and O128, whereas O139 was predominant in faecal strains from healthy birds. Iss, tsh e cva were more frequently detected among the septicaemic E. coli strains. The association of virulence genes was observed. Particularly, the pathotype iss-tsh-cva was present in 46.5% of APEC strains. Referring to serogroups, E. coli O78 and O2 originating from colibacillosis affected birds were always isstsh- cva positive but did not share virulence genes when they came from healthy birds.

  13. Alterations induced in Escherichia Coli cells by gamma radiation

    International Nuclear Information System (INIS)

    Modifications occurred in Escherichia coli cells exposed to gamma radiation (60Co source) were investigated. The irradiations were done at the LIN-COPPE laboratory of the UFRJ and the analysis at the Biology Department of the UTFPR. The E. coli cells were irradiated with 30, 60, 90, 120, 150, 180, 210, 240, 300, 480, 600 e 750 Gy doses. The samples were analyzed with Gram-stain, biochemical tests in EPM, MIO and Lysine Broth, Simmons Cytrate Medium and Rhamnose Broth, antibiogram and isolation of auxotrophic mutants. It was observed that for the received doses the E. coli did not show morphological alterations in the tests. Some E. Coli cells showed to be able to deaminade the L-tryptophan or they changed their sensibility for amoxillin and cephaloonine after the irradiation. The existence of aauxotrophic mutants after irradiation was also verified. (author)

  14. SILAC-based comparative analysis of pathogenic Escherichia coli secretomes

    DEFF Research Database (Denmark)

    Boysen, Anders; Borch, Jonas; Krogh, Thøger Jensen;

    2015-01-01

    this study, we grew the pathogenic strains ETEC H10407, AIEC LF82 and the non-pathogenic reference strain E. coli K-12 MG1655 in parallel and used SILAC to compare protein levels in OMVs and culture supernatant. We have identified well-known virulence factors from both AIEC and ETEC, thus validating......Comparative studies of pathogenic bacteria and their non-pathogenic counterparts has led to the discovery of important virulence factors thereby generating insight into mechanisms of pathogenesis. Protein-based antigens for vaccine development are primarily selected among unique virulence...... proteome analysis have the potential to discover both classes of proteins and hence form an important tool for discovering therapeutic targets. Adherent-invasive Escherichia coli (AIEC) and Enterotoxigenic E. coli (ETEC) are pathogenic variants of E. coli which cause intestinal disease in humans. AIEC is...

  15. Peptide nucleic acid (PNA) antisense effects in Escherichia coli

    DEFF Research Database (Denmark)

    Good, L; Nielsen, P E

    1999-01-01

    Antisense peptide nucleic acid (PNA) can be used to control cell growth, gene expression and growth phenotypes in the bacteria Escherichia coli. PNAs targeted to the RNA components of the ribosome can inhibit translation and cell growth, and PNAs targeted to mRNA can limit gene expression with gene...... and sequence specificity. In an E. coli cell extract, efficient inhibition is observed when using PNA concentrations in the nanomolar range, whereas micromolar concentrations are required for inhibition in growing cells. A mutant strain of E. coli that is more permeable to antibiotics also is more...... susceptible to antisense PNAs than the wild type. This chapter details methods for testing the antisense activities of PNA in E. coli. As an example of the specific antisense inhibition possible, we show the effects of an anti-beta-galactosidase PNA in comparison to control PNAs. With improvements in cell...

  16. Escherichia coli as Host and Pathogen

    OpenAIRE

    2013-01-01

    Enterohemorrhagic E. coli (EHEC) are highly infectious food-borne pathogens that cause severe diarrhoea in both, industrialised and developing countries all over the world. Their pathogenicity factors involve shiga-like toxins and a type III secretion system along with so called effector proteins, which are translocated directly into the cytoplasm of their host cells, usually enterocytes. Most of these proteins are encoded in pathogenicity islands within the bacterial genome that are framed b...

  17. Survival mechanism of Escherichia coli O157:H7 against combined treatment with acetic acid and sodium chloride.

    Science.gov (United States)

    Lee, Sun-Young; Kang, Dong-Hyun

    2016-05-01

    The combination of salt and acid is commonly used in the production of many foods, including pickles and fermented foods. However, in our previous studies, the addition of salt significantly reduced the inhibitory effect of acetic acid on Escherichia coli O157:H7 in laboratory media and pickled cucumbers. Therefore, this study was conducted to determine the mechanism by which salt confers resistance against acetic acid in E. coli O157:H7. The addition of high concentrations (up to 9% or 15% [w/v]) of salt increased the resistance of E. coli O157:H7 to acetic acid treatment. Combined treatment with acetic acid and salt showed varying results among different bacterial strains (an antagonistic effect for E. coli O157:H7 and Shigella and a synergistic effect for Listeria monocytogenes and Staphylococcus aureus). The addition of salt increased the cytoplasmic pH of E. coli O157:H7, but decreased the cytoplasmic pH of L. monocytogenes and S. aureus on treatment with acetic acid. Therefore, the addition of salt increases the acid resistance of E. coli O157:H7 possibly by increasing its acid resistance response and consequently preventing the acidification of its cytoplasm by organic acids. PMID:26742620

  18. Binding characteristics of Escherichia coli adhesins in human urinary bladder.

    OpenAIRE

    Virkola, R; Westerlund, B; Holthöfer, H; Parkkinen, J; Kekomäki, M; Korhonen, T K

    1988-01-01

    We studied domains in the human bladder that acted as receptors for Escherichia coli P, S, type 1, type 1C, and O75X fimbriae or adhesin and domains in the human kidneys that were receptors for E. coli type 1C fimbriae. Binding sites in frozen tissue sections were localized by direct staining with fluorochrome-labeled recombinant strains and by indirect immunofluorescence with the purified adhesins. In the bladder, the P and S fimbriae showed closely similar binding to the epithelial and musc...

  19. DNA microarray analysis of fim mutations in Escherichia coli

    DEFF Research Database (Denmark)

    Schembri, Mark; Ussery, David; Workman, Christopher;

    2002-01-01

    Bacterial adhesion is often mediated by complex polymeric surface structures referred to as fimbriae. Type I fimbriae of Escherichia coli represent the archetypical and best characterised fimbrial system. These adhesive organelles mediate binding to D-mannose and are directly associated with...... we have used DNA microarray analysis to examine the molecular events involved in response to fimbrial gene expression in E. coli K-12. Observed differential expression levels of the fim genes were in good agreement with our current knowledge of the stoichiometry of type I fimbriae. Changes in fim...

  20. Novel Aggregative Adherence Fimbria Variant of Enteroaggregative Escherichia coli

    DEFF Research Database (Denmark)

    Jønsson, Rie; Struve, Carsten; Boisen, Nadia;

    2015-01-01

    Enteroaggregative Escherichia coli (EAEC) organisms belong to a diarrheagenic pathotype known to cause diarrhea and can be characterized by distinct aggregative adherence (AA) in a stacked-brick pattern to cultured epithelial cells. In this study, we investigated 118 EAEC strains isolated from the....... Transformation to a nonadherent E. coli HB101 and complementation of the nonadherent C338-14 mutant with the complete gene cluster restored the AA adhesion. Overall, we found the agg5A gene in 12% of the 118 strains isolated from Denmark, suggesting that this novel adhesin represents an important variant....

  1. Recombinant protein expression in Escherichia coli: advances and challenges

    Directory of Open Access Journals (Sweden)

    GermánLeandroRosano

    2014-04-01

    Full Text Available Escherichia coli is the organism of choice for the production of recombinant proteins. Its use as a cell factory is well-established and it has become the most popular expression platform. For this reason, there are many molecular tools and protocols at hand for the high-level production of recombinant proteins, such as a vast catalog of expression plasmids, a great number of engineered strains and many cultivation strategies. We review the different approaches for the synthesis of recombinant proteins in E. coli and discuss recent progress in this ever-growing field.

  2. Antibacterial behavior of diamond nanoparticles against Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Beranova, Jana; Seydlova, Gabriela [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 16200 Prague (Czech Republic); Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Vinicna 5, 12844 Prague (Czech Republic); Kozak, Halyna; Potocky, Stepan; Kromka, Alexander [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 16200 Prague (Czech Republic); Konopasek, Ivo [Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Vinicna 5, 12844 Prague (Czech Republic)

    2012-12-15

    In this study, we investigated the potential antibacterial properties of nanocrystalline diamond. In particular, we tested the effect of diamond nanoparticles (DNPs) on growth of the model gram-negative bacterium Escherichia coli on solid, nutrient-rich growth medium. We found that the presence of DNPs on agar plates significantly reduced the colony forming ability of E. coli. The antibacterial effect occurred in a concentration dependent manner and was conditional on the specific ratio of DNPs to the number of bacterial cells. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Genetic determinants of heat resistance in Escherichia coli

    OpenAIRE

    Ryan eMercer; Jinshui eZheng; Rigoberto eGarcia-Hernandez; Lifang eRuan; Michael eGänzle; Lynn eMcMullen

    2015-01-01

    Escherichia coli AW1.7 is a heat resistant food isolate and the occurrence of pathogenic strains with comparable heat resistance may pose a risk to food safety. To identify the genetic determinants of heat resistance, 29 strains of E. coli that differed in their of heat resistance were analyzed by comparative genomics. Strains were classified as highly heat resistant strains, exhibiting a D60-value of more than 6 min; moderately heat resistant strains, exhibiting a D60-value of more than 1 mi...

  4. FimH-mediated autoaggregation of Escherichia coli

    DEFF Research Database (Denmark)

    Schembri, Mark; Christiansen, G.; Klemm, Per

    2001-01-01

    Autoaggregation is a phenomenon thought to contribute to colonization of mammalian hosts by pathogenic bacteria. Type 1 fimbriae are surface organelles of Escherichia coli that mediate D-mannose-sensitive binding to various host surfaces. This binding is conferred by the minor fimbrial component...... FimH. In this study, we have used random mutagenesis to identify variants of the FimH adhesin that confer the ability of E. coli to autoaggregate and settle from liquid cultures. Three separate autoaggregating clones were identified, all of which contained multiple amino acid changes located within...

  5. Properties and biosynthesis of cyclopropane fatty acids in Escherichia coli.

    Science.gov (United States)

    Cronan, J E; Reed, R; Taylor, F R; Jackson, M B

    1979-01-01

    The lipid phase transition of Escherichia coli phospholipids containing cyclopropane fatty acids was compared with the otherwise homologous phospholipids lacking cyclopropane fatty acids. The phase transitions (determined by scanning calorimetry) of the two preparations were essentially identical. Infection of E. coli with phage T3 inhibited cyclopropane fatty acid formation over 98%, whereas infection with mutants which lack the phage coded S-adenosylmethionine cleavage enzyme had no effect on cyclopropane fatty acid synthesis. These data indicate that S-adenosylmethionine is the methylene in cyclopropane fatty acid synthesis. PMID:374358

  6. Molecular basis of valine resistance in Escherichia coli K-12.

    OpenAIRE

    Lawther, R P; Calhoun, D H; Adams, C W; Hauser, C A; Gray, J.; Hatfield, G W

    1981-01-01

    The relationship of valine resistance to the expression of the ilvGEDA operon of Escherichia coli K-12 has been determined. DNA sequence and in vivo protein analyses indicate that in wild-type E. coli K-12 there is a frameshift site within the gene (ilvG) for valine resistance. The ilvG+2096 (formerly designated ilv02096) mutation displaces this frameshift site, resulting in the expression of ilvG and the relief of transcriptional polarity on the distal genes of this operon. Thus, the "ilv0" ...

  7. Isolation and Characterization of Potential Probiotic Escherichia coli Strains from Rat Faecal Samples

    Directory of Open Access Journals (Sweden)

    Prasant Kumar

    2009-01-01

    Full Text Available Problem statement: Gastrointestinal disorders mainly diarrhea is the most common cause of morbidity and mortality among infants and children in the developing countries occurs due to infection by enteropathogens. Ccontrol of these pathogens could be achieved by nonpathogenic Escherichia coli producing bacteriocins. Approach: Primary aim of this study was to isolate E. coli strains which inhibit enteropathogens. For this purpose, E. coli strains were isolated and tested for probiotic properties such as antimicrobial activity against enteropathogens, antibiotic susceptibility and resistance to low pH, absence of virulence traits, susceptibility to proteolytic activity and detection of colicins type. Results: Approximately 280 E. coli strains were collected from rat feacal samples at different ages and were screened for their antimicrobial activity. Out of these, 47 isolates showed antimicrobial effect against E. coli DH5α and BL21 strains and 16 were effective against different pathogens viz. Salmonella sp., Klebisella pneumoniae, Staphylococcus aureus and Enterobacter sp. These 16 isolates were susceptible to the common Antibiotics and most of them better survived at pH 3 and a few survived even at pH 2. Colony PCR of these isolates with colicinogenic primer demonstrated the presence of multiple colicin types. Out of 16 isolates, 12 had multiple pore forming colicins of E1 and 1a/1b type. In addition to the pore forming E1 and 1a/1b colicins, four E. coli strains 16, 2P and 14, 20 had Emix (nuclease type/BD type (translation blocker colicins, respectively. Conclusion: This study showed that E. coli isolates 10, 14 and 14 P possess good probiotic properties and could be effective against enteropathogens.

  8. Dexamethazone protects against Escherichia coli induced sickness behavior in rats.

    Science.gov (United States)

    Hanaa-Mansour, A; Hassan, Wedad A; Georgy, Gehan S

    2016-01-01

    Systemic bacterial infection results in systemic inflammatory response syndrome due to the release of lipopolysaccharide (LPS) in blood that can lead to multiple organ failure, shock, and potentially death. Other impact, LPS exposure produces robust increase in anxiety-like behavior, suppression of locomotor, exploratory activity, and reduced social behavior. The therapeutic use of glucocorticoids in septic shock remains one of the first-aid approaches for their anti-inflammatory properties. The aim of this study was to evaluate the possible protective effect of dexamethazone (DEX), the most commonly used corticosteroid, against Escherichia coli (E. coli) immunohistochemical changes and neurobehavioral dysfunction. To this end, male Sprague-Dawley rats were divided into four groups; (1) Control group (2) E. coli infected group, where animals received 0.2 ml of 24 h growth of E. coli suspension in nutrient broth containing approximately 1.8×10(8) cfu/ml i.p for once, 48 h before sacrificing (3) DEX (20 mg/kg, i.p, 3 days) treated group (4) DEX and E. coli treated group. The results revealed that DEX significantly protected animals against most E. coli-induced behavioral deficits, reduced signs of cognitive impairment. DEX also reduced the LPS-evoked rise in C-reactive protein (CRP), Interferon gamma (IFγ), as well as, expression of Caspase-3. In conclusion, DEX provides neuroprotection against E. coli-associated neurobehavioral and immunological changes via its anti-inflammatory and immunomodulatory effects. PMID:26541583

  9. Mechanobiology of Antimicrobial Resistant Escherichia coli and Listeria innocua

    Science.gov (United States)

    Tajkarimi, Mehrdad; Harrison, Scott H.; Hung, Albert M.; Graves, Joseph L.

    2016-01-01

    A majority of antibiotic-resistant bacterial infections in the United States are associated with biofilms. Nanoscale biophysical measures are increasingly revealing that adhesive and viscoelastic properties of bacteria play essential roles across multiple stages of biofilm development. Atomic Force Microscopy (AFM) applied to strains with variation in antimicrobial resistance enables new opportunities for investigating the function of adhesive forces (stickiness) in biofilm formation. AFM force spectroscopy analysis of a field strain of Listeria innocua and the strain Escherichia coli K-12 MG1655 revealed differing adhesive forces between antimicrobial resistant and nonresistant strains. Significant increases in stickiness were found at the nanonewton level for strains of Listeria innocua and Escherichia coli in association with benzalkonium chloride and silver nanoparticle resistance respectively. This advancement in the usage of AFM provides for a fast and reliable avenue for analyzing antimicrobial resistant cells and the molecular dynamics of biofilm formation as a protective mechanism. PMID:26914334

  10. Findings of Escherichia coli and Enterococcus spp. in homemade cheese

    OpenAIRE

    Tambur Zoran; Opačić Dolores; Doder Radoje; Marković Miroslav

    2007-01-01

    During the period from February until March 2004, 108 samples of soft cheese originating from markets of Pancevo, Subotica and Belgrade were examined. Microbiological analyses of the cheese samples to the presence of Escherichia coli was performed using methods described in the Regulations on methods for performing microbiological analyses and super analyses of consumer articles, while the presence of bacteria Enteroccocus spp. was performed on the dexter agar. From 108 samples of soft cheese...

  11. Mechanistic aspects of thiamine biosynthesis in escherichia coli

    OpenAIRE

    Challand, M.R

    2011-01-01

    The biosynthesis of the vitamin thiamine is laden with interesting chemistry. In anaerobic bacteria (such as Escherichia coli) a reactive intermediate, dehydroglycine, required for the biosynthesis of the thiazole moiety is derived from cleavage of the C??C? bond of tyrosine in a reaction catalysed by the radical S-adenosyl-L-methionine (SAM) enzyme, tyrosine lyase (ThiH). The aromatic by-product of this reaction in vivo was unequivocally characterised as p-cresol, a result which supported pr...

  12. Polynucleotide Phosphorylase Protects Escherichia coli against Oxidative Stress†

    OpenAIRE

    Wu, Jinhua; Jiang, Zhe; Liu, Min; Gong, Xin; Wu, ShaoHui; Burns, Christopher M.; Li, Zhongwei

    2009-01-01

    Escherichia coli polynucleotide phosphorylase (PNPase) primarily functions in RNA degradation. It is an exoribonuclease and integral component of the multienzyme RNA degradosome complex [Carpousis et al. (1994) Cell 76, 889]. PNPase was previously shown to specifically bind a synthetic RNA containing the oxidative lesion 8-hydroxyguanine (8-oxoG) [Hayakawa et al. (2001) Biochemistry 40, 9977], suggesting a possible role in removing oxidatively damaged RNA. Here we show that PNPase binds to RN...

  13. Chromosome partition in Escherichia coli requires postreplication protein synthesis.

    OpenAIRE

    Donachie, W. D.; Begg, K J

    1989-01-01

    After inhibition of protein synthesis, the number of nuclear bodies (nucleoids) visible in cells of Escherichia coli B/rA corresponded closely to the number of completely replicated chromosomes. We calculated that nucleoid partition follows almost immediately after replication forks reach the chromosome terminus. We show that such a partition is dependent on protein synthesis and that this may reflect the requirement that cells must achieve a certain minimum length before partition (and subse...

  14. Occurrence of Escherichia coli in Wild Cottontail Rabbits.

    Science.gov (United States)

    Kozlowski, R; Glantz, P J; Anthony, R G

    1977-03-01

    Free-ranging cottontail rabbits (Sylvilagus floridanus) from two areas in central Pennsylvania were sampled over a 4-year period. Large numbers of coliforms were isolated from the intestinal tracts of these animals; in 136 of the 141 rabbits sampled, Escherichia coli was found to be a major component of the alimentary flora. Four serogroups (O7, O77, O73, and O103) were predominant among the isolates and were considered resistant coliflora of this species of cottontail rabbit. PMID:16345208

  15. Identification of Uropathogenic Escherichia coli Surface Proteins by Shotgun Proteomics

    OpenAIRE

    Walters, Matthew S.; Mobley, Harry L. T.

    2009-01-01

    Uropathogenic Escherichia coli (UPEC) cause the majority of uncomplicated urinary tract infections in humans. In the process of identifying candidate antigens for a vaccine, two methods for the identification of the UPEC surface proteome during growth in human urine were investigated. The first approach utilized a protease to ‘shave’ surface-exposed peptides from the bacterial cell surface and identify them by mass spectrometry. Although this approach has been successfully applied to a Gram-p...

  16. Expression of a proline-enriched protein in Escherichia coli.

    OpenAIRE

    Kangas, T T; Cooney, C L; Gomez, R F

    1982-01-01

    The feasibility of expressing repeated synthetic codons in bacterial cells was demonstrated by showing that repeated codons for proline were expressed in Escherichia coli. Recombinant DNA technology was used to clone synthetic polydeoxyguanylate:polydeoxycytidylate into the PstI site of plasmid pBR322. Recombinant plasmid pGC139 was shown by means of HaeIII restriction digestion to contain approximately 41 cloned base pairs; the cloned sequence was expressed as a fusion to an ampicillinase pr...

  17. Genetic Analysis of the Maltose A Region in Escherichia coli

    Science.gov (United States)

    Hatfield, Dolph; Hofnung, Maurice; Schwartz, Maxime

    1969-01-01

    The genetic map of the maltose A locus of Escherichia coli contains at least three closely linked genes, malT, malP, and malQ. The order of these genes is established by deletion mapping. MalP and malQ, the presumed structural genes for maltodextrin phosphorylase and amylomaltase, belong to the same operon. MalT may be a regulator gene involved in the positive control of this operon. PMID:4891257

  18. 2DBase: 2D-PAGE database of Escherichia coli

    OpenAIRE

    Vijayendran, Chandran; Burgemeister, Sebastian; Friehs, Karl; Niehaus, Karsten; Flaschel, Erwin

    2007-01-01

    We present a web-based integrated proteome database, termed 2DBase of Escherichia coli which was designed to store, compare, analyse, and retrieve various information obtained by 2D polyacrylamide gel electrophoresis and mass spectrometry. The main objectives of this database are (1) to provide the features for query and data-mining applications to access the stored proteomics data (2) to efficiently compare the specific protein spots present in the comparable proteome maps and (3) to analyse...

  19. Metabolic engineering of Escherichia coli for the production of cinnamaldehyde

    OpenAIRE

    Bang, Hyun Bae; Lee, Yoon Hyeok; Kim, Sun Chang; Sung, Chang Keun; Jeong, Ki Jun

    2016-01-01

    Background Plant parasitic nematodes are harmful to agricultural crops and plants, and may cause severe yield losses. Cinnamaldehyde, a volatile, yellow liquid commonly used as a flavoring or food additive, is increasingly becoming a popular natural nematicide because of its high nematicidal activity and, there is a high demand for the development of a biological platform to produce cinnamaldehyde. Results We engineered Escherichia coli as an eco-friendly biological platform for the productio...

  20. Structural systems biology evaluation of metabolic thermotolerance in Escherichia coli

    OpenAIRE

    Chang, Roger L.; Andrews, Kathleen; Kim, Donghyuk; Li, Zhanwen; Godzik, Adam; Palsson, Bernhard Ø.

    2013-01-01

    Genome scale network reconstruction has enabled predictive modeling of metabolism for many systems. Traditionally, protein structural information has not been represented in such reconstructions. Expanding a genome-scale model of Escherichia coli metabolism by including experimental and predicted protein structures enabled the analysis of protein thermostability in a network context, allowing prediction of protein activities that limit network function at super-optimal temperature and mechani...

  1. Pet, an Autotransporter Enterotoxin from Enteroaggregative Escherichia coli

    OpenAIRE

    Eslava, Carlos; Navarro-García, Fernando; Czeczulin, John R.; Henderson, Ian R.; Cravioto, Alejandro; James P. Nataro

    1998-01-01

    Enteroaggregative Escherichia coli (EAEC) is an emerging cause of diarrheal illness. Clinical data suggest that diarrhea caused by EAEC is predominantly secretory in nature, but the responsible enterotoxin has not been described. Work from our laboratories has implicated a ca. 108-kDa protein as a heat-labile enterotoxin and cytotoxin, as evidenced by rises in short-circuit current and falls in tissue resistance in rat jejunal tissue mounted in an Ussing chamber. Here we report the genetic cl...

  2. The stringent response and cell cycle arrest in Escherichia coli.

    OpenAIRE

    Daniel J Ferullo; Lovett, Susan T.

    2008-01-01

    The bacterial stringent response, triggered by nutritional deprivation, causes an accumulation of the signaling nucleotides pppGpp and ppGpp. We characterize the replication arrest that occurs during the stringent response in Escherichia coli. Wild type cells undergo a RelA-dependent arrest after treatment with serine hydroxamate to contain an integer number of chromosomes and a replication origin-to-terminus ratio of 1. The growth rate prior to starvation determines the number of chromosomes...

  3. The Stringent Response and Cell Cycle Arrest in Escherichia coli

    OpenAIRE

    Daniel J Ferullo; Lovett, Susan T.

    2008-01-01

    The bacterial stringent response, triggered by nutritional deprivation, causes an accumulation of the signaling nucleotides pppGpp and ppGpp. We characterize the replication arrest that occurs during the stringent response in Escherichia coli. Wild type cells undergo a RelA-dependent arrest after treatment with serine hydroxamate to contain an integer number of chromosomes and a replication origin-to-terminus ratio of 1. The growth rate prior to starvation determines the number of chromosomes...

  4. Conjugative plasmid transfer from Enterococcus faecalis to Escherichia coli.

    OpenAIRE

    Trieu-Cuot, P; Carlier, C; Courvalin, P

    1988-01-01

    The possibility of transfer of genetic information by conjugation from gram-positive to gram-negative bacteria was investigated with a pBR322-pAM beta 1 chimeric plasmid, designated pAT191. This shuttle vector, which possesses the tra functions of the streptococcal plasmid pAM beta 1, was conjugatively transferred from Enterococcus faecalis to Escherichia coli with an average frequency of 5 x 10(-9) per donor colony formed after mating.

  5. Widespread antibiotic resistance of diarrheagenic Escherichia coli and Shigella species

    OpenAIRE

    Azam Fatahi Sadeghabadi; Ali Ajami; Reza Fadaei; Masoud Zandieh; Elham Heidari; Mahmoud Sadeghi; Behrooz Ataei; Shervin Ghaffari Hoseini

    2014-01-01

    Background: Antibiotic resistance of enteric pathogens particularly Shigella species, is a critical world-wide problem and monitoring their resistant pattern is essential, because the choice of antibiotics is absolutely dependent on regional antibiotic susceptibility patterns. During summer 2013, an unusual increase in number of diarrheal diseases was noticed in Isfahan, a central province of Iran. Therefore, the antibiotic resistance of diarrheagenic Escherichia coli and Shigella species iso...

  6. Functional expression of mouse mdr1 in Escherichia coli.

    OpenAIRE

    Bibi, E; Gros, P.; Kaback, H R

    1993-01-01

    We describe functional expression of the mouse multidrug-resistance protein (P-glycoprotein; P-gp) in an Escherichia coli mutant defective in the outer membrane protease ompT. Heterologously expressed mdr1 appears as an unglycosylated species with an apparent molecular mass of 140 kDa in the membrane of the mutant. Unglycosylated mdr1 retains the ability to bind the photoactivatable drug analog [125I]iodoarylazidoprazosin and confers resistance to tetraphenylphosphonium (TPP+) and tetraphenyl...

  7. CRISPR-Cas Functional Module Exchange in Escherichia coli

    OpenAIRE

    Almendros, Cristóbal; Mojica, Francisco J. M.; Díez-Villaseñor, César; Guzmán, Noemí M.; García-Martínez, Jesús

    2014-01-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (cas) genes constitute the CRISPR-Cas systems found in the Bacteria and Archaea domains. At least in some strains they provide an efficient barrier against transmissible genetic elements such as plasmids and viruses. Two CRISPR-Cas systems have been identified in Escherichia coli, pertaining to subtypes I-E (cas-E genes) and I-F (cas-F genes), respectively. In order to unveil the evolutionary dynamics of ...

  8. Vaccinia DNA topoisomerase I promotes illegitimate recombination in Escherichia coli.

    OpenAIRE

    Shuman, S

    1989-01-01

    Vaccinia virus encapsidates a Mr 32,000 type IDNA topoisomerase. Although the vaccinia gene encoding the topoisomerase is essential for virus growth, the role of the enzyme in vivo remains unclear. In the present study, the physiologic consequences of vaccinia topoisomerase action have been examined in a heterologous system, Escherichia coli. The vaccinia topoisomerase gene was inducibly expressed in an int-lambda lysogen BL21(DE3) using a T7 RNA polymerase-based transcription system. Express...

  9. Spurious hydrogen sulfide production by Providencia and Escherichia coli species.

    OpenAIRE

    Treleaven, B E; Diallo, A. A.; Renshaw, E C

    1980-01-01

    Hydrogen sulfide production was noted in two Escherichia coli strands and one Provaidenica alcalifaciens (Proteus inconstans A) strain isolated from clinical stool specimens durin the summer of 1979. An investigation into this phenomenon revealed the predence of Eubacterium lentum, an anaerobe, growing in synergism with the Enterobacteriaceae and producing H2s. The implications of this association are discssed with reference to clinical microbiology laboratory practice.

  10. Clonal relationships among bloodstream isolates of Escherichia coli.

    OpenAIRE

    Maslow, J.N.; Whittam, T S; Gilks, C F; Wilson, R A; Mulligan, M E; Adams, K S; Arbeit, R D

    1995-01-01

    The clonal relationships among 187 bloodstream isolates of Escherichia coli from 179 patients at Boston, Mass., Long Beach, Calif., and Nairobi, Kenya, were determined by multilocus enzyme electrophoresis (MLEE), analysis of polymorphisms associated with the ribosomal operon (ribotyping), and serotyping. MLEE based on 20 enzymes resolved 101 electrophoretic types (ETs), forming five clusters; ribotyping resolved 56 distinct patterns concordant with the analysis by MLEE. The isolates at each s...

  11. Pathogenomics of the Virulence Plasmids of Escherichia coli

    OpenAIRE

    Johnson, Timothy J.; Lisa K. Nolan

    2009-01-01

    Summary: Bacterial plasmids are self-replicating, extrachromosomal elements that are key agents of change in microbial populations. They promote the dissemination of a variety of traits, including virulence, enhanced fitness, resistance to antimicrobial agents, and metabolism of rare substances. Escherichia coli, perhaps the most studied of microorganisms, has been found to possess a variety of plasmid types. Included among these are plasmids associated with virulence. Several types of E. col...

  12. Genome-Scale Thermodynamic Analysis of Escherichia coli Metabolism

    OpenAIRE

    Christopher S Henry; Jankowski, Matthew D.; Broadbelt, Linda J.; Hatzimanikatis, Vassily

    2005-01-01

    Genome-scale metabolic models are an invaluable tool for analyzing metabolic systems as they provide a more complete picture of the processes of metabolism. We have constructed a genome-scale metabolic model of Escherichia coli based on the iJR904 model developed by the Palsson Laboratory at the University of California at San Diego. Group contribution methods were utilized to estimate the standard Gibbs free energy change of every reaction in the constructed model. Reactions in the model wer...

  13. Uropathogenic Escherichia coli Flagella Aid in Efficient Urinary Tract Colonization

    OpenAIRE

    Wright, Kelly J.; Seed, Patrick C.; Hultgren, Scott J.

    2005-01-01

    In the murine model of urinary tract infections (UTI), cystitis by uropathogenic Escherichia coli (UPEC) occurs through an intimate relationship with the bladder superficial umbrella cell entailing cycles of adherence, invasion, intracellular bacterial community (IBC) formation, and dispersal (fluxing) from the intracellular environment. IBC dispersal is a key step that results in the spread of bacteria over the epithelial surface to initiate additional rounds of IBC formation. We investigate...

  14. Escherichia coli and virus isolated from ''sticky kits''

    DEFF Research Database (Denmark)

    Jørgensen, M.; Scheutz, F.; Strandbygaard, Bertel

    1996-01-01

    A total of 121 Escherichia coli strains isolated from 3-week-old mink kits were serotyped and examined for virulence factors. 56 strains were isolated from healthy kits while 65 were from ''sticky kits''. Among these, 34 different serotypes were detected. No difference in serotypes or the presence...... of virulence factors could be detected between healthy and diseased kits. By electron microscopy of faecal samples corona-, rota-, and calicivirus were demonstrated among healthy as well as diseased kits....

  15. Analysis of resynthesis tracts in repaired Escherichia coli deoxyribonucleic acid.

    OpenAIRE

    Kuemmerle, N; R. Ley; Masker, W

    1981-01-01

    Excision repair of ultraviolet radiation-induced damage in a wild-type strain of Escherichia coli has been examined, using two methods for characterizing the resynthesis step of the repair process. Comparison of data obtained after both isopycnic analysis of repaired deoxyribonucleic acid and sedimentation velocity analysis of deoxyribonucleic acid after selective photolysis of bromouracil-containing repaired regions has shown that the repaired deoxyribonucleic acid molecules contain a semico...

  16. relA Enhances the Adherence of Enteropathogenic Escherichia coli

    OpenAIRE

    Beny Spira; Gerson Moura Ferreira; Luiz Gustavo de Almeida

    2014-01-01

    Enteropathogenic Escherichia coli (EPEC) is a known causative agent of diarrhea in children. In the process of colonization of the small intestine, EPEC synthesizes two types of adhesins, the bundle-forming pilus (BFP) and intimin. The BFP pilus is an adhesin associated with the initial stages of adherence of EPEC to epithelial cells, while the outer membrane protein intimin carries out the intimate adherence that takes place at the third stage of infection. BFP is encoded by the bfp operon l...

  17. Induction and control of the autolytic system of Escherichia coli.

    OpenAIRE

    Leduc, M.; Kasra, R; van Heijenoort, J

    1982-01-01

    Various methods of inducing autolysis of Escherichia coli cells were investigated, some being described here for the first time. For the autolysis of growing cells only induction methods interfering with the biosynthesis of peptidoglycan were taken into consideration, whereas with harvested cells autolysis was induced by rapid osmotic or EDTA shock treatments. The highest rates of autolysis were observed after induction by moenomycin, EDTA, or cephaloridine. The different autolyses examined s...

  18. Mobilization of Thiobacillus ferrooxidans plasmids among Escherichia coli strains.

    OpenAIRE

    Rawlings, D. E.; Woods, D R

    1985-01-01

    Nonconjugative Thiobacillus ferrooxidans plasmids were mobilized at high frequencies among Escherichia coli strains by the IncP plasmid RP4 and at low frequencies by the IncN plasmid R46, but not by the IncW plasmid pSa. The mobilization region of a nonconjugative T. ferrooxidans plasmid was located on a 5.3-kilobase T. ferrooxidans DNA fragment.

  19. 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.

  20. The asymptomatic bacteriuria Escherichia coli strain 83972 outcompetes uropathogenic E. coli strains in human urine

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Ulett, G.C.; Schembri, M.A.;

    2006-01-01

    Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infections (UTI), very little is known about the mechanisms by which these strains colonize the human urinary tract. The...... prototype ABU E. coli strain 83972 was originally isolated from a girl who had carried it asymptomatically for 3 years. Deliberate colonization of UTI-susceptible individuals with E. coli 83972 has been used successfully as an alternative approach for the treatment of patients who are refractory to...... conventional therapy. Colonization with strain 83972 appears to prevent infection with UPEC strains in such patients despite the fact that this strain is unable to express the primary adhesins involved in UTI, viz. P and type 1 fimbriae. Here we investigated the growth characteristics of E. coli 83972 in human...

  1. Escherichia coli. A sanitary methodology for faecal water pollution tests; Escherichia coli nelle acque. Significato sanitario e metodologie di analisi

    Energy Technology Data Exchange (ETDEWEB)

    Bonadonna, L. [Istituto Superiore di Sanita' , Rome (Italy)

    2001-02-01

    Among the traditional indictors of faecal water pollution, Escherichia coli has shown to fit better with the definition of indicator organism. Till now its recovery has been time-consuming and needs confirmation tests. In this report more rapid and direct methods, based on enzymatic reactions, are presented. [Italian] Per talune peculiari caratteristiche, Escherichia coli sembra meglio soddisfare i requisiti insiti nella definizione di organismo indicatore, rispetto ai tradizionali indicatori di contaminazione fecale dell'acqua. Finora, i substrati disponibili per il suo rilevamento necessitano tutti di almeno una prova di conferma. Di qui l'esigenza di indicare metodi di rilevamento a riposta piu' rapida, anche in relazione all'inserimento, nelle piu' recenti normative nazionali ed europee, del microrganismo tra i parametri microbiologici da ricercare.

  2. Escherichia coli sequence type 131: epidemiology and challenges in treatment.

    Science.gov (United States)

    Qureshi, Zubair A; Doi, Yohei

    2014-05-01

    Escherichia coli ST131 has emerged as a global epidemic, multidrug-resistant clone of E. coli causing extra-intestinal infections. It is now highly prevalent among fluoroquinolone-resistant and CTX-M ESBL-producing E. coli isolates worldwide. Humans are likely the primary reservoir of ST131. Factors associated with its acquisition include residence in long-term care facilities and recent receipt of antimicrobial agents. E. coli ST131 causes a wide array of infections ranging from cystitis to life-threatening sepsis. Fluoroquinolones and trimethoprim-sulfamethoxazole are no longer adequate options for empiric therapy when E. coli ST131 is suspected from risk factors and local epidemiology. Expanded-spectrum cephalosporins, piperacillin-tazobactam and carbapenems are options to treat serious non-ESBL-producing E. coli ST131 infections, while carbapenems are indicated for ESBL-producing infections. There is a growing interest in reevaluating oral agents including fosfomycin and pivmecillinam for less serious infections such as uncomplicated cystitis. PMID:24694052

  3. A stochastic killing system for biological containment of Escherichia coli

    DEFF Research Database (Denmark)

    Klemm, P.; Jensen, Lars Bogø; Molin, Søren

    1995-01-01

    Bacteria with a stochastic conditional lethal containment system have been constructed. The invertible switch promoter located upstream of the fimA gene from Escherichia coli was inserted as expression cassette in front of the Lethal gef gene deleted of its own natural promoter. The resulting...... fusion was placed on a plasmid and transformed to E. coli. The phenotype connected with the presence of such a plasmid was to reduce the population growth rate with increasing significance as the cell growth rate was reduced. In very fast growing cells, there was no measurable effect on growth rate. When...... a culture of E. coli harboring the plasmid comprising the containment system is left as stationary cells in suspension without nutrients, viability drops exponentially over a period of several days, in contrast to the control cells, which maintain viability nearly unaffected during the same period...

  4. The Escherichia coli transcriptome linked to growth fitness

    Directory of Open Access Journals (Sweden)

    Bei-Wen Ying

    2016-03-01

    Full Text Available A series of Escherichia coli strains with varied genomic sequences were subjected to high-density microarray analyses to elucidate the fitness-correlated transcriptomes. Fitness, which is commonly evaluated by the growth rate during the exponential phase, is not only determined by the genome but is also linked to growth conditions, e.g., temperature. We previously reported genetic and environmental contributions to E. coli transcriptomes and evolutionary transcriptome changes in thermal adaptation. Here, we describe experimental details on how to prepare microarray samples that truly represent the growth fitness of the E. coli cells. A step-by-step record of sample preparation procedures that correspond to growing cells and transcriptome data sets that are deposited at the GEO database (GSE33212, GSE52770, GSE61739 are also provided for reference.

  5. Impact of antibiotic restriction on resistance levels of Escherichia coli

    DEFF Research Database (Denmark)

    Boel, Jonas; Andreasen, Viggo; Jarløv, Jens Otto;

    2016-01-01

    OBJECTIVES: We evaluated the effect of an antibiotic stewardship programme (ASP) on the use of antibiotics and resistance levels of Escherichia coli using a method that allowed direct comparison between an intervention hospital and a control hospital. METHODS: The study was conducted as a...... of E. coli. Results were directly compared with data from the control hospital utilizing a subtracted time series (STS). RESULTS: Direct comparison with the control hospital showed that the ASP was associated with a significant change in the level of use of cephalosporins [-151 DDDs/1000 bed-days (95......% CI -177, -126)] and fluoroquinolones [-44.5 DDDs/1000 bed-days (95% CI -58.9, -30.1)]. Resistance of E. coli showed a significant change in slope for cefuroxime [-0.13 percentage points/month (95% CI -0.21, -0.057)] and ciprofloxacin [-0.15 percentage points/month (95% CI -0.26, -0.038)]. CONCLUSIONS...

  6. Novel roles for the AIDA adhesin from diarrheagenic Escherichia coli:

    DEFF Research Database (Denmark)

    Sherlock, Orla; Schembri, Mark; Reisner, A.;

    2004-01-01

    Diarrhea-causing Escherichia coli strains are responsible for numerous cases of gastrointestinal disease and constitute a serious health problem throughout the world. The ability to recognize and attach to host intestinal surfaces is an essential step in the pathogenesis of such strains. AIDA is a...... potent bacterial adhesin associated with some diarrheagenic E. coli strains. AIDA mediates bacterial attachment to a broad variety of human and other mammalian cells. It is a surface-displayed autotransporter protein and belongs to the selected group of bacterial glycoproteins; only the glycosylated form...... binds to mammalian cells. Here, we show that AIDA possesses self-association characteristics and can mediate autoaggregation of E. coli cells. We demonstrate that intercellular AIDA-AIDA interaction is responsible for bacterial autoaggregation. Interestingly, AIDA-expressing cells can interact with...

  7. Escherichia coli portador de betalactamasas de espectro extendido: resistencia

    Directory of Open Access Journals (Sweden)

    Mª C. Miranda García

    2013-12-01

    Full Text Available Introducción: Escherichia coli es el microorganismo que con más frecuencia se encuentra implicado en infecciones nosocomiales y comunitarias, patógeno responsable en la etiología de infecciones de vías respiratorias altas, infecciones del tracto urinario, heridas quirúrgicas, sangre o gastroenteritis. En los últimos años ha experimentado importantes cambios encontrándose un aumento de infecciones por cepas de éstos microorganismos productores de betalactamasas de espectro extendido. Objetivos: Se decide hacer este estudio retrospectivo de las muestras procesadas en el Laboratorio de Microbiología del Hospital Básico de la Defensa San Carlos (San Fernando, para conocer la frecuencia y el patrón de sensibilidad en nuestra población por gérmenes productores de betalactamasas de espectro extendido en este caso por Escherichia coli, dada la importancia de las infecciones causadas por esta bacteria y la repercusión que tiene por todo el mundo los mecanismos de resistencia. Material y Método: Se recogieron los datos de resultados obtenidos en las muestras procesadas en el Laboratorio de Microbiología durante 36 meses (Enero 2009 a Diciembre 2011, en las que se hubieran identificado cepas de Escherichia coli y de éstas las productoras de betalactamasas de espectro extendido. Resultados: Se aislaron 34 cepas de Escherichia coli productoras de betalactamasas de espectro extendido lo que supone una tasa del 5,10%. Se encontró una frecuencia mayor en el año 2010 (6,9% que en el 2009 (2,61%, pero similar al 2011 (5,98%. Conclusión: La frecuencia de cepas Escherichia coli con betalactamasas de espectro extendido encontrada es similar a la de otros estudios realizados en España, pero la tasa de resistencia de algunos antimicrobianos como Amoxicilina/clavulánico, Cotrimoxazol y Fluorquinolonas en nuestra población es elevada.

  8. Effect of tannins on the in viro growth of Escherichia coli O157:H7 and in vivo growth of generic Escherichia coli excreted from steers

    Science.gov (United States)

    The effect of commercially available chestnut and mimosa tannins in vitro (experiment 1) or in vivo (experiment 2) on the growth or recovery of Escherichia coli O157:H7 or generic fecal E. coli was evaluated. In experiment 1, the mean growth rate of E. coli O157:H7, determined via the measurement o...

  9. Evaluation of the antimicrobial activity of chitosan and its quaternized derivative on E. coli and S. aureus growth

    Directory of Open Access Journals (Sweden)

    Rejane C. Goy

    2016-02-01

    Full Text Available Abstract Chitosan is largely known for its activity against a wide range of microorganisms, in which the most acceptable antimicrobial mechanism is found to include the presence of charged groups in the polymer backbone and their ionic interactions with bacteria wall constituents. This interaction suggests the occurrence of a hydrolysis of the peptidoglycans in the microorganism wall, provoking the leakage of intracellular electrolytes, leading the microorganism to death. The charges present in chitosan chains are generated by protonation of amino groups when in acid medium or they may be introduced via structural modification. This latter can be achieved by a methylation reaction resulting in a quaternized derivative with a higher polymeric charge density. Since the charges in this derivative are permanents, it is expected a most efficient antimicrobial activity. Hence, in the present study, commercial chitosan underwent quaternization processes and both (mother polymer and derivative were evaluated, in gel form, against Staphylococcus aureus (Gram-positive and Escherichia coli (Gram-negative, as model bacteria. The results, as acquired from turbidity measurements, differ between materials with an expressive reduction on the Gram-positive microorganism (S. aureus growth, while E. coli (Gram-negative strain was less sensitive to both polymers. Additionally, the antibacterial effectiveness of chitosan was strongly dependent on the concentration, what is discussed in terms of spatial polymer conformation.

  10. Effective medicinal plants against enterohaemorrhagic Escherichia coli O157:H7.

    Science.gov (United States)

    Voravuthikunchai, Supayang; Lortheeranuwat, Amornrat; Jeeju, Wanpen; Sririrak, Trechada; Phongpaichit, Souwalak; Supawita, Thanomjit

    2004-09-01

    The stimulating effect of subinhibitory concentrations of antibiotics on the production of verocytotoxin (VT) by enterohaemorrhagic Escherichia coli (EHEC) O157:H7 has been claimed. The purpose of this study was to find an alternative, but bioactive medicine for the treatment of this organism. Fifty-eight preparations of aqueous and ethanolic extracts of 38 medicinal plant species commonly used in Thailand to cure gastrointestinal infections were tested for their antibacterial activity against different strains of Escherichia coli, including 6 strains of Escherichia coli O157:H7, Escherichia coli O26:H11, Escherichia coli O111:NM, Escherichia coli O22; 5 strains of Escherichia coli isolated from bovine; and Escherichia coli ATCC 25922. Inhibition of growth was primarily tested by the paper disc agar diffusion method. Among the medicinal plants tested, only 8 species (21.05%) exhibited antimicrobial activity against Escherichia coli O157:H7. Acacia catechu, Holarrhena antidysenterica, Peltophorum pterocarpum, Psidium guajava, Punica granatum, Quercus infectoria, Uncaria gambir, and Walsura robusta demonstrated antibacterial activity with inhibition zones ranging from 7 to 17 mm. The greatest inhibition zone against Escherichia coli O157:H7 (RIMD 05091083) was produced from the ethanolic extract of Quercus infectoria. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined by the agar microdilution method and agar dilution method in petri dishes with millipore filter. Both aqueous and ethanolic extracts of Quercus infectoria and aqueous extract of Punica granatum were highly effective against Escherichia coli O157:H7 with the best MIC and MBC values of 0.09, 0.78, and 0.19, 0.39 mg/ml, respectively. These plant species may provide alternative but bioactive medicines for the treatment of Escherichia coli O157:H7 infection. PMID:15261962

  11. Cloning and expression of secreted antigens of Clostridium difficile in Escherichia coli.

    OpenAIRE

    Dailey, D C; Schloemer, R H

    1988-01-01

    The feasibility of the cloning and expression of Clostridium difficile antigens in Escherichia coli was investigated. The expression of a limited number of cloned clostridial antigens under the control of clostridial promoter elements in E. coli was observed.

  12. Expresión en escherichia coli de un peptido perteneciente a la proteina vp1 del virus del polio

    Directory of Open Access Journals (Sweden)

    Myriam Sánchez de Gómez

    2010-07-01

    Full Text Available Una secuencia sintética de 49 pb codificante para un péptido de la cubierta del virus del Polio se clonó en el vector de fusión pEZZ8, basado en el gen de la proteína A del Staphylococcus aureus. La expresión se hizo en Escherichia coli y la proteína de fusión se recuperó en el sobrenadante. Se purificó mediante cromatografía de afinidad con IgG Sepharosa y se identificó por medio de electroforesis en presencia de SDS.

  13. Role of peripheral pooling in porcine Escherichia coli sepsis

    International Nuclear Information System (INIS)

    In anesthesized pigs the effects of E. coli (2 X 10(8)/kg) on hemodynamics and red cell distribution were studied. After injection of 99m-Tc red cells (15 mCi), regional radioactivity was followed during 3 hours. Gated bloodpool studies were performed to measure end-diastolic volumes (EDV). Escherichia coli E. coli was infused in 14 pigs, while 7 animals served as controls. E. coli resulted in an early increase in pulmonary arterial pressure. Systemic arterial pressure decreased gradually, while cardiac output did not change significantly. The gated studies revealed that especially left ventricular end-diastolic volume (LVEDV) declined, to 50% of the basal value. Regional radioactivity did not change over lungs, liver and abdomen. Splenic activity declined markedly. Over the hindlimb a significant increase (29 +/- 8%) was observed. It is concluded that E. coli infusion in pigs induces a hemodynamic pattern similar to human sepsis. The decrease in LVEDV is probably related to peripheral pooling and a change in right ventricle (RV) performance

  14. Phylogenetic analysis of Escherichia coli strains isolated from human samples

    Directory of Open Access Journals (Sweden)

    Abdollah Derakhshandeh

    2013-12-01

    Full Text Available Escherichia coli (E. coli is a normal inhabitant of the gastrointestinal tract of vertebrates, including humans. Phylogenetic analysis has shown that E. coli is composed of four main phylogenetic groups (A, B1, B2 and D. Group A and B1 are generally associated with commensals, whereas group B2 is associated with extra-intestinal pathotypes. Most enteropathogenic isolates, however, are assigned to group D. In the present study, a total of 102 E. coli strains, isolated from human samples, were used. Phylogenetic grouping was done based on the Clermont triplex PCR method using primers targeted at three genetic markers, chuA, yjaA and TspE4.C2. Group A contained the majority of the collected isolates (69 isolates, 67.64%, followed by group B2 (18 isolates, 17.64% and D (15 isolates, 14.7% and no strains were found to belong to group B1. The distribution of phylogenetic groups in our study suggests that although the majority of strains were commensals, the prevalence of enteropathogenic and extra-intestinal pathotypes was noteworthy. Therefore, the role of E. coli in human infections including diarrhea, urinary tract infections and meningitis should be considered.

  15. Selective detection of Escherichia coli DNA using fluorescent carbon spindles.

    Science.gov (United States)

    Roy, Anurag; Chatterjee, Sabyasachi; Pramanik, Srikrishna; Devi, Parukuttyamma Sujatha; Suresh Kumar, Gopinatha

    2016-04-28

    We investigate the interaction of hydrophilic blue emitting carbon spindles with various deoxyribonucleic acids (DNA) having different base pair compositions, such as Herring testes (HT), calf thymus (CT), Escherichia coli (EC) and Micrococcus lysodeikticus (ML) DNA, to understand the mode of interaction. Interestingly, the fluorescent carbon spindles selectively interacted with E. coli DNA resulting in enhanced fluorescence of the former. Interaction of the same carbon with other DNAs exhibited insignificant changes in fluorescence. In addition, in the presence of EC DNA, the D band in the Raman spectrum attributed to the defect state completely disappeared, resulting in enhanced crystallinity. Microscopy images confirmed the wrapping of DNA on the carbon spindles leading to the assembly of spindles in the form of flowers. Dissociation of double-stranded DNA occurred upon interaction with carbon spindles, resulting in selective E. coli DNA interaction. The carbon spindles also exhibited a similar fluorescence enhancement upon treating with E. coli bacteria. These results confirm the possibility of E. coli detection in water and other liquid foods using such fluorescent carbon. PMID:27081680

  16. 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

  17. Escherichia coli B lacks one of the two initiator tRNA species present in E. coli K-12.

    OpenAIRE

    Mandal, N; RajBhandary, U L

    1992-01-01

    We show that the metY locus which specifies tRNA(2fMet) in Escherichia coli K-12 specifies tRNA(1fMet) in E. coli B. This conclusion is based on results of Southern blot analysis of E. coli B and K-12 DNAs and on polymerase chain reaction amplification, cloning, and sequencing of an approximately 200-bp region of DNA corresponding to the metY loci of E. coli B and E. coli K-12. We also show that the metY locus of E. coli B is transcriptionally active. E. coli strains transformed with the mult...

  18. Characterization of Escherichia coli Strains from Cases of Childhood Diarrhea in Provincial Southwestern Nigeria

    OpenAIRE

    Iruka N Okeke; Lamikanra, Adebayo; Steinrück, Hartmut; Kaper, James B.

    2000-01-01

    In a study carried out in small-town and rural primary health care centers in southwestern Nigeria, 330 Escherichia coli strains isolated from 187 children with diarrhea and 144 apparently healthy controls were examined for virulence traits. Based on the results of colony blot hybridization, strains were categorized as enteropathogenic E. coli (1.8%), enterotoxigenic E. coli (2.4%), enteroinvasive E. coli (1.2%), enterohemorrhagic E. coli (0.6%), enteroaggregative E. coli (10.3%), diffusely a...

  19. Viabilidad de Escherichia coli en presencia de diferentes contaminantes

    Directory of Open Access Journals (Sweden)

    Antonio Rivera T

    2006-04-01

    Full Text Available La contaminación en ríos condiciona la presencia de microorganismos adaptados al ecosistema entre ellos a patógenos de importancia en salud pública. Objetivo: Determinar la viabilidad de Escherichia coli en presencia de nitrato de plata, carbonato de amonio, fenol y formaldehído. Materiales y métodos: Se tomaron muestras de agua del río Alseseca, que luego se sembró en medios de cultivo selectivos para enterobacterias, seleccionándose las colonias del género Escherichia, las cuales fueron sembradas en el medio de orientación CHROMagar ECC. Las muestras de E. coli se evaluaron en presencia de nitrato de plata, carbonato de amonio, fenol y formaldehído. Resultados: El grupo experimental presentó viabilidad en presencia de los cuatro compuestos, el grupo control positivo presentó nula viabilidad, la comparación entre los grupos mostró diferencia significativa (p< 0,05. Conclusión: Los aislamientos de E. coli mostraron viabilidad, implicando riesgos para el ecosistemas y la salud, ya que el río Alseseca atraviesa por el municipio de Puebla donde existen núcleos poblacionales importantes.

  20. Inactivation of Escherichia coli in soil by solarization

    International Nuclear Information System (INIS)

    Contamination of agricultural soil by fecal pathogenic bacteria poses a potential risk of infection to humans. For the biosafety control of field soil, soil solarization in an upland field was examined to determine the efficiency of solarization on the inactivation of Escherichia coli inoculated into soil as a model microorganism for human pathogenic bacteria. Soil solarization, carried out by sprinkling water and covering the soil surface with thin plastic sheets, greatly increased the soil temperature. The daily average temperature of the solarized soil was 4–10°C higher than that of the non-solarized soil and fluctuated between 31 and 38°C. The daily highest temperature reached more than 40°C for 8 days in total in the solarized soil during the second and third weeks of the experiment. Escherichia coli in the solarized soil became undetectable (< 0.08 c.f.u. g−1 dry soil) within 4 weeks as a result, whereas E. coli survived for more than 6 weeks in the non-solarized soil. Soil solarization, however, had little influence on the total direct count and total viable count of bacteria in the soil. These results indicate that soil solarization would be useful for the biosafety control of soil contaminated by human pathogens via immature compost or animal feces. (author)

  1. Overexpression and export of Vibrio anguillarum metalloprotease in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Zhang Fengli; Chi Zhenming; Chen Jixiang; Wu Longfei; Liang Likun

    2007-01-01

    Vibrio anguillarum metalloprotease, an extracellular zinc metalloprotease involved in the virulence mechanism of Vibrio anguillarum, is synthesized from the empA gene as a 611-residue precursor and naturally secreted via Sec secretion pathway in Vibrio anguillarum. In this study, heterologous expression of the empA gene encoding metallopmtease and export of the recombinant metalloprotease in Escherichia coliwere examined. The empA gene was subcloned into pBAD24 with arabinose promoter and sequenced. The sequence encoded a polypeptide(611 amino acids)consisting of four domains: a signal peptide, an Nterminal propeptide, a mature region and a C-terminal propeptide. The empA gene inserted in plasmid pBAD24 was overexpressed in TOP10 strain of E. Coli after arabinose induction. The 36kDa polypeptide of the recombinant metalloprotease as the mature protease was further confirmed by SDS-PAGE and immunoblotting. It was found that recombinant metalloprotease with the EmpA activity and antigenicity wasexported into the periplasm of Escherichia coli cells via Sec translocation pathway, whereas it was secreted into extracellular environments in V. Anguillarum. The results imply that the expression, export and processing mechanism of the protein in E. Coli are similar to those in V. Anguillarum.

  2. Widespread antibiotic resistance of diarrheagenic Escherichia coli and Shigella species

    Directory of Open Access Journals (Sweden)

    Azam Fatahi Sadeghabadi

    2014-01-01

    Full Text Available Background: Antibiotic resistance of enteric pathogens particularly Shigella species, is a critical world-wide problem and monitoring their resistant pattern is essential, because the choice of antibiotics is absolutely dependent on regional antibiotic susceptibility patterns. During summer 2013, an unusual increase in number of diarrheal diseases was noticed in Isfahan, a central province of Iran. Therefore, the antibiotic resistance of diarrheagenic Escherichia coli and Shigella species isolated were evaluated. Materials and Methods: According to the guideline on National Surveillance System for Foodborn Diseases, random samples from patients with acute diarrhea were examined in local laboratories of health centers and samples suspicious of Shigella spp. were further assessed in referral laboratory. Isolated pathogens were identified by standard biochemical and serologic tests and antibiotic susceptibility testing was carried out by disc diffusion method. Results: A total of 1086 specimens were obtained and 58 samples suspicious of Shigella were specifically evaluated. The most prevalent isolated pathogen was Shigella sonnei (26/58 followed by E. coli (25/58 and Shigella flexneri (3/58. A large number of isolated bacteria were resistant to co-trimoxazole (Shigella spp: 100%, E. coli: 80%, azithromycin (Shigella spp: 70.4%, E. coli: 44.0%, ceftriaxone (Shigella spp: 88.9%, E. coli: 56.0% and cefixime (Shigella spp: 85.2%, E. coli: 68.0%. About88.3% of S. sonnei isolates, one S. flexneri isolate, and 56% of E. coli strains were resistant to at least three antibiotic classes (multidrug resistant. Conclusion: Due to high levels of resistance to recommended and commonly used antibiotics for diarrhea, continuous monitoring of antibiotic resistance seems essential for determining best options of empirical therapy.

  3. Toxicity mechanism of carbon nanotubes on Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Young, Yu-Fu [Department of Materials Science and Engineering, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Lee, Hui-Ju [Department of Life Science, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Shen, Yi-Shan; Tseng, Shih-Hao; Lee, Chi-Young [Department of Materials Science and Engineering, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Tai, Nyan-Hwa, E-mail: nhtai@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Chang, Hwan-You, E-mail: hychang@mx.nthu.edu.tw [Department of Life Science, National Tsing-Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer F-MWCNTs possess higher antibiotic performance than that of the F-SWCNTs. Black-Right-Pointing-Pointer E. coli cells were pierced when incubated with F-MWCNTs and trapped when incubated with F-SWCNTs. Black-Right-Pointing-Pointer The rigidity and moment of CNTs play important role on the antibiotic effect. - Abstract: The influences of carbon nanomaterials on bacteria were investigated using three types of dispersed and functionalized carbon nanomaterials (F-CNMs), viz. functionalized carbon nanopowder (F-CNP), functionalized single-walled carbon nanotubes (F-SWCNTs), and functionalized multi-walled carbon nanotubes (F-MWCNTs). F-CNMs with different aspect ratios were used to study the influence of material configuration on the viability of Escherichia coli (E. coli). Although these materials were functionalized to improve their dispersibility, the original morphologies and chemical properties of the materials were maintained. Traditional bacteria quantitative plating analysis was conducted, and the results of which revealed that the F-CNP and the F-SWCNTs showed a less significant effect on the viability of E. coli, while the F-MWCNTs obviously inhibited cell viability. A Fourier transform infrared spectroscopy and a scanning electron microscopy were used to verify the functionalization of the F-CNMs and to examine the interaction of F-CNMs with E. coli, respectively; in addition, we adopted chemiluminescence assays to measure the concentration of adenosine triphosphate (ATP) released from the damaged cells. The results showed that the ATP of the F-MWCNTs sample is two-fold higher than that of the control, indicating direct piercing of E. coli by F-MWCNTs leads to bacteria death. Furthermore, F-SWCNTs were concluded to have less influence on the viability of E. coli because ultra-long F-SWCNTs used in this study performed less rigidity to pierce the cells.

  4. Multiplex PCR for Diagnosis of Enteric Infections Associated with Diarrheagenic Escherichia coli

    OpenAIRE

    Vidal, Roberto; Vidal, Maricel; Lagos, Rossana; Levine, Myron; Prado, Valeria

    2004-01-01

    A multiplex PCR for detection of three categories of diarrheagenic Escherichia coli was developed. With this method, enterohemorrhagic E. coli, enteropathogenic E. coli, and enterotoxigenic E. coli were identified in fecal samples from patients with hemorrhagic colitis, watery diarrhea, or hemolytic-uremic syndrome and from food-borne outbreaks.

  5. IDENTIFIKASI DAN UJI AKTIVITAS ANTIBAKTERI FRAKSI TERAKTIF DAUN PACAR KUKU (Lawsonia inermis Linn. TERHADAP Staphylococcus aureus DAN Escherischia coli

    Directory of Open Access Journals (Sweden)

    Nestri Handayani

    2013-11-01

    Full Text Available Telah dilakukan uji aktivitas antibakteri fraksi teraktif daun pacar kuku (Lawsonia inermis Linn. terhadap bakteri Staphylococcus aureusdan Escherichia coli. Fraksi teraktif diperoleh dari hasil pemisahan kromatografi vacum cair (KVC ekstrak etanol daun pacar kuku (Lawsonia inermis Linn. yang telah melalui tahap maserasi dengan pelarut etanol 70%. Proses KVC dilakukan dengan menggunakan tiga eluen yaitu n-heksan, etil asetat, dan etanol. Pengujian aktivitas antibakteri dilakukan dengan metode difusi agar. Komponen kimia dalam fraksi teraktif diidentifikasi melalui skrining fitokimia dengan metode kromatografi lapis tipis (KLT dan kromatografi gas-spektrometer massa (GC-MS.Uji aktivitas antibakteri menunjukkan bahwa ekstrak etanol dan fraksi-fraksi daun pacar kuku (Lawsonia inermis Linn. mampu menghambat pertumbuhan bakteri Staphylococcus aureus dan Escherichia coli. Fraksi etil asetat adalah fraksi teraktif anti bakteri.Identifikasi senyawa dalam fraksi teraktif melalui kromatografi lapis tipis (KLT menunjukkan adanya golongan senyawa flavonoid, terpenoid, antrakuinon, saponin, dan asam lemak. Analisis GC-MS menunjukkan adanya senyawa dominan 2-pentanone,4-hydroxy-4 methy, coumarin, hexadecanoic acid, methyl ester, dan 10-octadecanoic acid.

  6. Binding of Escherichia coli S fimbriae to human kidney epithelium

    OpenAIRE

    Korhonen, T K; Parkkinen, J; Hacker, Jörg; Finne, J; Pere, A; Rhen, M; Holthöfer, H

    2011-01-01

    Purified S fimbriae and an Escherichia coli strain carrying the recombinant plasmid pANN801-4 that encodes S fimbriae were tested for adhesion to frozen sections of human kidney. The fimbriae and the bacteria bound to the same tissue domains, and in both cases the binding was specifically inhibited by the receptor analog of S fimbria, sialyl(alpha 2-3)lactose. S fimbriae bound specifically to the epithelial elements in the kidneys; to the epithelial cells of proximal and distal tubules as wel...

  7. Characterization of RNA damage under oxidative stress in Escherichia coli

    OpenAIRE

    Liu, Min; Gong, Xin; Alluri, Ravi Kumar; Wu, Jinhua; Sablo, Tene’; Li, Zhongwei

    2012-01-01

    We have examined the level of 8-hydroxyguanosine (8-oxo-G), an oxidized form of guanosine, in RNA in Escherichia coli under normal and oxidative stress conditions. The level of 8-oxo-G in RNA rises rapidly and remains high for hours in response to hydrogen peroxide (H2O2) challenge in a dose-dependent manner. H2O2 induced elevation of 8-oxo-G content is much higher in RNA than that of 8-hydroxydeoxyguanosine (8-oxo-dG) in DNA. Under normal conditions, the 8-oxo-G level is low in RNA isolated ...

  8. Effect of Zinc in Enteropathogenic Escherichia coli Infection▿ †

    OpenAIRE

    Crane, John K.; Naeher, Tonniele M.; Shulgina, Irina; Zhu, Chengru; Boedeker, Edgar C.

    2007-01-01

    Enteropathogenic Escherichia coli (EPEC) infection triggers the release of ATP from host intestinal cells, and the ATP is broken down to ADP, AMP, and adenosine in the lumen of the intestine. Ecto-5′-nucleotidase (CD73) is the main enzyme responsible for the conversion of 5′-AMP to adenosine, which triggers fluid secretion from host intestinal cells and also has growth-promoting effects on EPEC bacteria. In a recent study, we examined the role of the host enzyme CD73 in EPEC infection by test...

  9. Replication initiation at the Escherichia coli chromosomal origin

    OpenAIRE

    Kaguni, Jon M.

    2011-01-01

    To initiate DNA replication, DnaA recognizes and binds to specific sequences within the Escherichia coli chromosomal origin (oriC), and then unwinds a region within oriC. Next, DnaA interacts with DnaB helicase in loading the DnaB-DnaC complex on each separated strand. Primer formation by primase (DnaG) induces the dissociation of DnaC from DnaB, which involves the hydrolysis of ATP bound to DnaC. Recent evidence indicates that DnaC acts as a checkpoint in the transition from initiation to th...

  10. Tetrahydrothiophene 1-oxide as an electron acceptor for Escherichia coli.

    OpenAIRE

    Meganathan, R; Schrementi, J

    1987-01-01

    Escherichia coli used tetrahydrothiophene 1-oxide (THTO) as an electron acceptor for anaerobic growth with glycerol as a carbon source; the THTO was reduced to tetrahydrothiophene. Cell extracts also reduced THTO to tetrahydrothiophene in the presence of a variety of electron donors. Chlorate-resistant (chl) mutants (chlA, chlB, chlD, and chlE) were unable to grow with THTO as the electron acceptor. However, growth and THTO reduction by the chlD mutant were restored by high concentrations of ...

  11. Multiple joined genes prevent product degradation in Escherichia coli.

    OpenAIRE

    Shen, S H

    1984-01-01

    A method is described that allows the expression of a stable human proinsulin product in Escherichia coli as encoded by either a fused or an unfused gene construction. In the fused system, the human proinsulin coding sequence is joined to the 3' side of a fragment containing the lac promoter and the coding sequence for a small part of the NH2 terminus of beta-galactosidase. In the unfused system, the proinsulin coding sequence is linked directly to a fragment containing the Tac promoter follo...

  12. Carbon and energy metabolism of atp mutants of Escherichia coli

    DEFF Research Database (Denmark)

    Jensen, Peter Ruhdal; Michelsen, Ole

    1992-01-01

    The membrane-bound H+-ATPase plays a key role in free-energy transduction of biological systems. We report how the carbon and energy metabolism of Escherichia coli changes in response to deletion of the atp operon that encodes this enzyme. Compared with the isogenic wild-type strain, the growth...... rate and growth yield were decreased less than expected for a shift from oxidative phosphorylation to glycolysis alone as a source of ATP. Moreover, the respiration rate of a atp deletion strain was increased by 40% compared with the wild-type strain. This result is surprising, since the atp deletion...

  13. Transcriptional Response of Escherichia coli to External Zinc

    OpenAIRE

    Yamamoto, Kaneyoshi; Ishihama, Akira

    2005-01-01

    Transcriptional response of Escherichia coli to extracellular zinc was studied using DNA microarray and S1 mapping assays. Addition of external zinc induced the expression of zinc exporter ZntA and inhibited the expression of zinc importer ZnuC. In the continuous presence of zinc, ZnuC repression took place at lower zinc concentrations than ZntA induction. The microarray assay indicated that the addition of excess external zinc induces the expression of many genes that are organized in the re...

  14. Rapid test for assay of ozone sensitivity in Escherichia coli

    International Nuclear Information System (INIS)

    A rapid test devised for assay of ozone sensitivity in Escherichia coli based on the procedure used by Chung and Greenberg (1968) for assay of radiation sensitivity is described. The detection of new mutants, either more resistant or more sensitive than wild type strain to ozone, and the genetic analysis of ozone recombinants are now possible. Results confirm that ozone resistance is probably involved with DNA repair mechanisms; and show that ozone and ultraviolet light inhibit the cell division capacity of lon mutants in a similar way. (orig.)

  15. Dual genetic selection of synthetic riboswitches in Escherichia coli.

    Science.gov (United States)

    Nomura, Yoko; Yokobayashi, Yohei

    2014-01-01

    This chapter describes a genetic selection strategy to engineer synthetic riboswitches that can chemically regulate gene expression in Escherichia coli. Riboswitch libraries are constructed by randomizing the nucleotides that potentially comprise an expression platform and fused to the hybrid selection/screening marker tetA-gfpuv. Iterative ON and OFF selections are performed under appropriate conditions that favor the survival or the growth of the cells harboring the desired riboswitches. After the selection, rapid screening of individual riboswitch clones is performed by measuring GFPuv fluorescence without subcloning. This optimized dual genetic selection strategy can be used to rapidly develop synthetic riboswitches without detailed computational design or structural knowledge. PMID:24549616

  16. Identification, Expression, and Characterization of Escherichia coli Guanine Deaminase

    OpenAIRE

    Maynes, Jason T.; Yuan, Richard G.; Snyder, Floyd F.

    2000-01-01

    Using the human cDNA sequence corresponding to guanine deaminase, the Escherichia coli genome was scanned using the Basic Local Alignment Search Tool (BLAST), and a corresponding 439-residue open reading frame of unknown function was identified as having 36% identity to the human protein. The putative gene was amplified, subcloned into the pMAL-c2 vector, expressed, purified, and characterized enzymatically. The 50.2-kDa protein catalyzed the conversion of guanine to xanthine, having a Km of ...

  17. Modulation of allele leakiness and adaptive mutability in Escherichia coli

    Indian Academy of Sciences (India)

    R. Jayaraman

    2000-08-01

    It is shown that partial phenotypic suppression of two ochre mutations (argE3 and lacZU118) and an amber mutation (in argE) by sublethal concentrations of streptomycin in an rpsL+ (streptomycin-sensitive) derivative of the Escherichia coli strain AB1157 greatly enhances their adaptive mutability under selection. Streptomycin also increases adaptive mutability brought about by the ppm mutation described earlier. Inactivation of recA affects neither phenotypic suppression by streptomycin nor replication-associated mutagenesis but abolishes adaptive mutagenesis. These results indicate a causal relationship between allele leakiness and adaptive mutability.

  18. relA-dependent RNA polymerase activity in Escherichia coli.

    OpenAIRE

    Ryals, J; Bremer, H

    1982-01-01

    Parameters relating to RNA synthesis were measured after a temperature shift from 30 to 42 degrees C, in a relA+ and relA- isogenic pair of Escherichia coli strains containing a temperature-sensitive valyl tRNA synthetase. The following results were obtained: (i) the rRNA chain growth rate increased 2-fold in both strains; (ii) newly synthesized rRNA became unstable in both strains; (iii) the stable RNA gene activity (rRNA and tRNA, measured as stable RNA synthesis rate relative to the total ...

  19. The action of beta-galactosidase (Escherichia coli) on allolactose.

    Science.gov (United States)

    Huber, R E; Wallenfels, K; Kurz, G

    1975-09-01

    The parameters involved in the action of beta-galactosidase (EC 3.2.1.23) (Escherichia coli) on allolactose, the natural inducer of lac operon in E. coli, were studied. At low allolactose concentrations only galactose and glucose were formed, while at high allolactose concentrations transgalactolytic oligosaccharides were also produced. Detectable amounts of lactose were not formed. The V and Km values (49.6 U/mg and 0.00120 M, respectively) indicated that allolactose is as good if not a better substrate of beta-galactosidase as lactose. The pH optimum with allolactose (7.8-7.9) as well as its activation by K+ (as compared to activation by Na+) were similar to the case with lactose as substrate. The alpha-anomer of allolactose was hydrolyzed about two times as rapidly as was the beta-anomer. PMID:241475

  20. Antimicrobial activity of peptidomimetics against multidrug-resistant Escherichia coli

    DEFF Research Database (Denmark)

    Jahnsen, Rasmus D; Frimodt-Møller, Niels; Franzyk, Henrik

    2012-01-01

    Novel remedies in the battle against multidrug-resistant bacterial strains are urgently needed, and one obvious approach involves antimicrobial peptides and mimics hereof. The impact of a- and ß-peptoid as well as ß(3)-amino acid modifications on the activity profile against ß......-lactamase-producing Escherichia coli was assessed by testing an array comprising different types of cationic peptidomimetics obtained by a general monomer-based solid-phase synthesis protocol. Most of the peptidomimetics possessed high to moderate activity toward multidrug-resistant E. coli as opposed to the corresponding...... inactive peptides. Nevertheless, differences in hemolytic activities indicate that a careful choice of backbone design constitutes a significant parameter in the search for effective cationic antimicrobial peptidomimetics targeting specific bacteria....

  1. Human Insulin Modulation of Escherichia coli Adherence and Chemotaxis

    Directory of Open Access Journals (Sweden)

    Karolina Klosowska

    2006-01-01

    Full Text Available Escherichia coli exhibited increased hydrophobicity and mannose-resistant epithelial cell adherence after growth in the presence of human insulin (2 µU mLˉ1 or 200 µUmLˉ1 insulin, respectively with glucose (100 mg dLˉ1. Capsule production and hemagglutination were unaffected by insulin and glucose. Chemotactic attraction to glucose as compared to insulin or glucose alone was enhanced by the presence of insulin. Insulin alone (200 µU mLˉ1 was a chemorepellent and inhibited flagellar tethering to glass. These findings indicate that human insulin can modulate E. coli’s expression of factors associated with pathogenesis in a manner that is modifiable by the presence of glucose.

  2. Engineering Escherichia coli Cell Factories for n-Butanol Production.

    Science.gov (United States)

    Dong, Hongjun; Zhao, Chunhua; Zhang, Tianrui; Lin, Zhao; Li, Yin; Zhang, Yanping

    2016-01-01

    The production of n-butanol, as a widely applied solvent and potential fuel, is attracting much attention. The fermentative production of butanol coupled with the production of acetone and ethanol by Clostridium (ABE fermentation) was once one of the oldest biotechnological processes, ranking second in scale behind ethanol fermentation. However, there remain problems with butanol production by Clostridium, especially the difficulty in genetically manipulating clostridial strains. In recent years, many efforts have been made to produce butanol using non-native strains. Until now, the most advanced effort was the engineering of the user-friendly and widely studied Escherichia coli for butanol production. This paper reviews the current progress and problems relating to butanol production by engineered E. coli in terms of prediction using mathematical models, pathway construction, novel enzyme replacement, butanol toxicity, and tolerance engineering strategies. PMID:25662903

  3. Impact of cranberry on Escherichia coli cellular surface characteristics

    International Nuclear Information System (INIS)

    The anti-adhesive effects of cranberry have been attributed to both interactions of its components with the surface of bacterial cells and to inhibition of p-fimbriae expression. Previous reports also suggested that the presence of cranberry juice changed the Gram stain characteristics of Escherichia coli. Here, we show that the morphology of E. coli is changed when grown in the presence of juice or extract from Vaccinium macrocarpon (cranberry). Gene expression analysis indicates the down regulation of flagellar basal body rod and motor proteins. Consistent with this finding and previous reports, the SEM images indicate a decrease in the visible p-fimbriae. The iodine used in Gram-staining protocols was found to interact differently with the bacterial membrane when cells were cultured in spiked media. Slight alterations in the Gram stain protocol demonstrated that culturing in the presence of cranberry juice does not change the Gram stain characteristics contradicting other reports.

  4. Sickness behavior in dairy cows during Escherichia coli mastitis

    DEFF Research Database (Denmark)

    Fogsgaard, Katrine Kop; Røntved, Christine Maria; Sørensen, Peter;

    2012-01-01

    -recorded on 5 consecutive days, d −2 to +2 after challenge when the cows were not disturbed by humans. The behavior of the animals was compared among all days. Infection with E. coli altered the behavior of the dairy cows. Time spent feeding was lower in the initial 24 h after infection compared with that on......The consequences of mastitis in terms of dairy cow behavior are relatively unknown. Future assessment of dairy cow welfare during mastitis will be facilitated by knowledge about the potential of mastitis to induce sickness behavior. Our aim was to examine behavior of dairy cows in the period from 2...... d before (d −2 and −1) to 3 d (d 0, 1, and 2) after experimental intramammary challenge with Escherichia coli. Effects of experimentally induced mastitis on behavior were examined in 20 primiparous Danish Holstein-Friesian cows, all 3 to 6 wk after calving and kept in tie stalls. After evening...

  5. Assessment of Escherichia coli isolates for In vitro biofilm production

    Directory of Open Access Journals (Sweden)

    A.I. Dadawala

    Full Text Available A total of 14 Escherichia coli isolates were assessed for their ability to produce biofilm in-vitro by slime production on Congo red agar medium (CRA and microtitre plate assay. Out of 14 isolates tested, 12 were slime producing on CRA as indicated by black colonies. The isolates of E.coli varied in their ability to produce biofilm on the surface of microtitre plate ranging from 0.101 to 0.543 ODm. Out of 14 isolates tested, 10 were positive for biofilm production employing criterion of blank corrected ODs9s > 0.1. Two of slime negative isolated were also negative for biofilm production where as the two slime positive isolates were found to be negative for biofilm production. [Veterinary World 2010; 3(8.000: 364-366

  6. Metabolite essentiality elucidates robustness of Escherichia coli metabolism

    CERN Document Server

    Kim, Pan-Jun; Kim, Tae Yong; Lee, Kwang Ho; Jeong, Hawoong; Lee, Sang Yup; Park, Sunwon

    2007-01-01

    Complex biological systems are very robust to genetic and environmental changes at all levels of organization. Many biological functions of Escherichia coli metabolism can be sustained against single-gene or even multiple-gene mutations by using redundant or alternative pathways. Thus, only a limited number of genes have been identified to be lethal to the cell. In this regard, the reaction-centric gene deletion study has a limitation in understanding the metabolic robustness. Here, we report the use of flux-sum, which is the summation of all incoming or outgoing fluxes around a particular metabolite under pseudo-steady state conditions, as a good conserved property for elucidating such robustness of E. coli from the metabolite point of view. The functional behavior, as well as the structural and evolutionary properties of metabolites essential to the cell survival, was investigated by means of a constraints-based flux analysis under perturbed conditions. The essential metabolites are capable of maintaining a...

  7. In Vivo study of naturally deformed Escherichia coli bacteria.

    Science.gov (United States)

    Tavaddod, Sharareh; Naderi-Manesh, Hossein

    2016-06-01

    A combination of light-microscopy and image processing has been applied to study naturally deformed Escherichia coli under in vivo condition and at the order of sub-pixel high-resolution accuracy. To classify deflagellated non-dividing E. coli cells to the rod-shape and bent-shape, a geometrical approach has been applied. From the analysis of the geometrical data which were obtained of image processing, we estimated the required effective energy for shaping a rod-shape to a bent-shape with the same size. We evaluated the energy of deformation in the naturally deformed bacteria with minimum cell manipulation, under in vivo condition, and with minimum influence of any external force, torque and pressure. Finally, we have also elaborated on the possible scenario to explain how naturally deformed bacteria are formed from initial to final-stage. PMID:27026097

  8. Deactivation of Escherichia coli by the plasma needle

    Energy Technology Data Exchange (ETDEWEB)

    Sladek, R E J; Stoffels, E [Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2005-06-07

    In this paper we present a parameter study on deactivation of Escherichia coli (E. coli) by means of a non-thermal plasma (plasma needle). The plasma needle is a small-sized (1 mm) atmospheric glow sustained by radio-frequency excitation. This plasma will be used to disinfect heat-sensitive objects; one of the intended applications is in vivo deactivation of dental bacteria: destruction of plaque and treatment of caries. We use E. coli films plated on agar dishes as a model system to optimize the conditions for bacterial destruction. Plasma power, treatment time and needle-to-sample distance are varied. Plasma treatment of E. coli films results in formation of a bacteria-free void with a size up to 12 mm. 10{sup 4}-10{sup 5} colony forming units are already destroyed after 10 s of treatment. Prolongation of treatment time and usage of high powers do not significantly improve the destruction efficiency: short exposure at low plasma power is sufficient. Furthermore, we study the effects of temperature increase on the survival of E. coli and compare it with thermal effects of the plasma. The population of E. coli heated in a warm water bath starts to decrease at temperatures above 40 deg. C. Sample temperature during plasma treatment has been monitored. The temperature can reach up to 60 deg. C at high plasma powers and short needle-to-sample distances. However, thermal effects cannot account for bacterial destruction at low power conditions. For safe and efficient in vivo disinfection, the sample temperature should be kept low. Thus, plasma power and treatment time should not exceed 150 mW and 60 s, respectively.

  9. Deactivation of Escherichia coli by the plasma needle

    International Nuclear Information System (INIS)

    In this paper we present a parameter study on deactivation of Escherichia coli (E. coli) by means of a non-thermal plasma (plasma needle). The plasma needle is a small-sized (1 mm) atmospheric glow sustained by radio-frequency excitation. This plasma will be used to disinfect heat-sensitive objects; one of the intended applications is in vivo deactivation of dental bacteria: destruction of plaque and treatment of caries. We use E. coli films plated on agar dishes as a model system to optimize the conditions for bacterial destruction. Plasma power, treatment time and needle-to-sample distance are varied. Plasma treatment of E. coli films results in formation of a bacteria-free void with a size up to 12 mm. 104-105 colony forming units are already destroyed after 10 s of treatment. Prolongation of treatment time and usage of high powers do not significantly improve the destruction efficiency: short exposure at low plasma power is sufficient. Furthermore, we study the effects of temperature increase on the survival of E. coli and compare it with thermal effects of the plasma. The population of E. coli heated in a warm water bath starts to decrease at temperatures above 40 deg. C. Sample temperature during plasma treatment has been monitored. The temperature can reach up to 60 deg. C at high plasma powers and short needle-to-sample distances. However, thermal effects cannot account for bacterial destruction at low power conditions. For safe and efficient in vivo disinfection, the sample temperature should be kept low. Thus, plasma power and treatment time should not exceed 150 mW and 60 s, respectively

  10. Longitudinal characterization of Escherichia coli in healthy captive nonhuman primates

    Directory of Open Access Journals (Sweden)

    Jonathan B Clayton

    2014-11-01

    Full Text Available The gastrointestinal (GI tracts of nonhuman primates are well known to harbor Escherichia coli, a known commensal of humans and animals. While E. coli is a normal inhabitant of the mammalian gut, it also exists in a number of pathogenic forms or pathotypes, including those with predisposition for the GI tract, as well the urogenital tract. Diarrhea in captive nonhuman primates (NHPs has long been a problem in both zoo settings and research colonies, including the Como Zoo. It is an animal welfare concern, as well as a public health concern. E. coli has not been extensively studied in correlation with diarrhea in captive primates; therefore, a study was performed during the summer of 2009 in collaboration with a zoo in Saint Paul, MN, which was experiencing an increased incidence and severity of diarrhea among their NHP collection. Fresh fecal samples were collected weekly from each member of the primate collection, between June and August of 2009, and E. coli were isolated. A total of 33 individuals were included in the study, representing eight species. E. coli isolates were examined for their genetic relatedness, phylogenetic relationships, plasmid replicon types, virulence gene profiles, and antimicrobial susceptibility profiles. A number of isolates were identified containing virulence genes commonly found in several different E. coli pathotypes, and there was evidence of clonal transmission of isolates between animals and over time. Overall, the manifestation of chronic diarrhea in the Como Zoo primate collection is a complex problem whose solution will require regular screening for microbial agents and consideration of environmental causes. This study provides some insight towards the sharing of enteric bacteria between such animals.

  11. ASSOCIATION OF ESCHERICHIA COLI WITH THE PREVALENCE OF FLIES POPULATION

    Directory of Open Access Journals (Sweden)

    Hassan Flayiah Hassan

    2013-01-01

    Full Text Available Mass releases of house fly Musca domestica (L and stable fly Stomoxys calcitrans (L. Produced by manure piles accumulated nearby horse stables and dairy farm village in Abu-Graib provide continuous threat to inhabitants west of Baghdad. Timing of fly’s mass release in association with the presence of Escherichia coli in manure piles was examined at these locations. Experimental result indicated that flies survived during cold period of December and January in form of larvae deep in manure piles where temperature was around 15-17°C. Once the population of fly’s larvae started to increase by the second week of February, the concentration of E. coli was up to 80×106 CFU mL-1 in manure suspension. Later when larval population reached to a maximum number by the last week of April, the concentration of E. coli in manure sample dropped down to 38×102 CFU mL-1. Similar trend was observed with the proportion of E. coli to general bacteria present in manure samples where the percent decreased from 89% in early season to 1.5% when maximum number of larvae was recorded. The correlation coefficient (R between the number of larvae and coli form bacteria was = -0.73657. These results suggest the association of larval development with the consumption of E. coli. Thus manipulation of bacterial community in manure piles may lead to possible eradication of fly’s seasonal release.

  12. Modification of Artificial Oliogosaccharides in Recombinant Escherichia coli Cells

    Directory of Open Access Journals (Sweden)

    Tomohisa Kato

    2008-01-01

    Full Text Available Artificial oligosaccharides were modified using recombinant Escherichia coli cells that overexpress sialidase. Based on the principle of the saccharide primer method by using bacterial cells overexpressing enzymes related to oligosaccharide modification. Problem statement: It is very hard to obtain oligosaccharides, because they have complex and diverse structures with different linkage patterns and monosaccharide components. Approach: It has been known that various oligosaccharides can be synthesized in mammalian cells from saccharide primers. We attempted to modify oligosaccharides by using bacterial cells overexpressing enzymes related to oligosaccharide modification instead of mammalian cells. Results: The glycosphingolipid-like derivative GM3 was absorbed by the cell and desialylated by the expressed sialidase and the desialylated product was then secreted into the medium. The GM3-type oligosaccharides were not detected from the cell fraction of recombinant E. coli cells that overexpress sialidase differently from recombinant E. coli carrying only vector DNA (pET-19b. Conclusion/Recommendations: E. coli as well as mammalian cells may be used as a biocatalyst for oligosaccharide modification and production of artificial functional oligosaccharides.

  13. Modeling Escherichia coli removal in constructed wetlands under pulse loading.

    Science.gov (United States)

    Hamaamin, Yaseen A; Adhikari, Umesh; Nejadhashemi, A Pouyan; Harrigan, Timothy; Reinhold, Dawn M

    2014-03-01

    Manure-borne pathogens are a threat to water quality and have resulted in disease outbreaks globally. Land application of livestock manure to croplands may result in pathogen transport through surface runoff and tile drains, eventually entering water bodies such as rivers and wetlands. The goal of this study was to develop a robust model for estimating the pathogen removal in surface flow wetlands under pulse loading conditions. A new modeling approach was used to describe Escherichia coli removal in pulse-loaded constructed wetlands using adaptive neuro-fuzzy inference systems (ANFIS). Several ANFIS models were developed and validated using experimental data under pulse loading over two seasons (winter and summer). In addition to ANFIS, a mechanistic fecal coliform removal model was validated using the same sets of experimental data. The results showed that the ANFIS model significantly improved the ability to describe the dynamics of E. coli removal under pulse loading. The mechanistic model performed poorly as demonstrated by lower coefficient of determination and higher root mean squared error compared to the ANFIS models. The E. coli concentrations corresponding to the inflection points on the tracer study were keys to improving the predictability of the E. coli removal model. PMID:24231031

  14. REVIEW VIRULENCE NATURE OF Escherichia coli IN NEONATAL SWINE

    Directory of Open Access Journals (Sweden)

    Nwiyi PAUL

    2015-11-01

    Full Text Available Piglet disease due to Enterotoxigenic Escherichia coli (ETEC are classical and associated typically with severe watery diarrhea within the first two weeks of life and occasionally some days after weaning in pigs. E.coli is a well-known and diverse organism though normally harmless commensal, but when it acquires mobile genetic elements becomes a highly pathogenic organism capable of causing a range of diseases. ETEC adhere to the small intestinal microvilli without inducing morphological lesions and produce enterotoxins acting locally on enterocytes. This leads to hyper-secretions and reduced absorption of electrolytes. The virulence attributes of ETEC are adhesions and toxins and the successful management of the disease is dependent on good understanding of these virulence factors. In pigs ETEC, the commonest adhesions are the fimbriae on the surface K88, K99, 987p, F18ab and F18ac. The enterotoxine of pigs ETEC are further classified into heat-labile (LT and heat-stable (ST. Other subdivisions of enterotoxin E. coli are LT, STb, STa, Stx2e. The adhesive fimbriae and enterotoxins of piglet ETEC can be evaluated using plasmids. Polymerase chain reaction (PCR is a specific test and had been used for virulence gene detection of ETEC. In this reviews, we focus on current opinions and knowledge of the various pathogenic pathways that E.coli uses to cause disease in piglet.

  15. Persistence of colicinogenic Escherichia coli in the mouse gastrointestinal tract

    Directory of Open Access Journals (Sweden)

    Giladi Itamar

    2009-08-01

    Full Text Available Abstract Background The ability of a bacterial strain to competitively exclude or displace other strains can be attributed to the production of narrow spectrum antimicrobials, the bacteriocins. In an attempt to evaluate the importance of bacteriocin production for Escherichia coli strain residence in the gastrointestinal tract, a murine model experimental evolution study was undertaken. Results Six colicin-producing, yet otherwise isogenic, E. coli strains were administered and established in the large intestine of streptomycin-treated mice. The strains' persistence, population density, and doubling time were monitored over a period of 112 days. Early in the experiment only minor differences in population density between the various colicin-producing and the non-producing control strains were detected. However, over time, the density of the control strains plummeted, while that of the colicin-producing strains remained significantly higher (F(7,66 = 2.317; P Conclusion The data presented here support prior claims that bacteriocin production may play a significant role in the colonization of E. coli in the gastrointestinal tract. Further, this study suggests that the ability to produce bacteriocins may prove to be a critical factor in determining the success of establishing probiotic E. coli in the gastrointestinal tract of humans and animals.

  16. Prevalence of Antibiotic Resistance in Escherichia coli Isolated from Poultry Meat Supply in Isfahan

    Directory of Open Access Journals (Sweden)

    Farhad Safarpordehkordi

    2014-08-01

    Conclusions: Despite the high contamination rate of chicken meat with Escherichia coli, majority of isolates had high resistance to common antibiotics. Complete cooking of meat and avoid indiscriminate prescribing of antibiotics, preventing the occurrence of food poisoning due to resistant Escherichia coli.

  17. Rapid Detection and Isolation of Escherichia coli O104:H4 from Milk Using Monoclonal Antibody-coated Magnetic Beads

    Science.gov (United States)

    Luciani, Mirella; Di Febo, Tiziana; Zilli, Katiuscia; Di Giannatale, Elisabetta; Armillotta, Gisella; Manna, Laura; Minelli, Fabio; Tittarelli, Manuela; Caprioli, Alfredo

    2016-01-01

    Monoclonal antibodies (MAbs) specific for the lipopolysaccharide (LPS) of Escherichia coli O104:H4 were produced by fusion of Sp2/O-Ag-14 mouse myeloma cells with spleen cells of Balb/c mice, immunized with heat-inactivated and sonicated E. coli O104:H4 bacterial cells. Four MAbs specific for the E. coli O104:H4 LPS (1E6G6, 1F4C9, 3G6G7, and 4G10D2) were characterized and evaluated for the use in a method for the detection of E. coli O104:H4 in milk samples that involves antibody conjugation to magnetic microbeads to reduce time and increase the efficiency of isolation. MAb 1E6G6 was selected and coupled to microbeads, then used for immuno-magnetic separation (IMS); the efficiency of the IMS method for E. coli O104:H4 isolation from milk was evaluated and compared to that of the EU RL VTEC conventional culture-based isolation procedure. Milk suspensions also containing other pathogenic bacteria that could potentially be found in milk (Campylobacter jejuni, Listeria monocytogenes, and Staphylococcus aureus) were also tested to evaluate the specificity of MAb-coated beads. Beads coated with MAb 1E6G6 showed a good ability to capture the E. coli O104:H4, even in milk samples contaminated with other bacteria, with a higher number of E. coli O104:H4 CFU reisolated in comparison with the official method (121 and 41 CFU, respectively, at 103 E. coli O104:H4 initial load; 19 and 6 CFU, respectively, at 102 E. coli O104:H4 initial load; 1 and 0 CFU, respectively, at 101 E. coli O104:H4 initial load). The specificity was 100%. PMID:27379071

  18. Mild gut inflammation modulates the proteome of intestinal Escherichia coli.

    Science.gov (United States)

    Schumann, Sara; Alpert, Carl; Engst, Wolfram; Klopfleisch, Robert; Loh, Gunnar; Bleich, André; Blaut, Michael

    2014-09-01

    Using interleukin 10-deficient (IL-10(-/-) ) and wild-type mice monoassociated with either the adherent-invasive Escherichia coli UNC or the probiotic E. coli Nissle, the effect of a mild intestinal inflammation on the bacterial proteome was studied. Within 8 weeks, IL-10(-/-) mice monoassociated with E. coli UNC exhibited an increased expression of several proinflammatory markers in caecal mucosa. Escherichia coli Nissle-associated IL-10(-/-) mice did not do so. As observed previously for E. coli from mice with acute colitis, glycolytic enzymes were downregulated in intestinal E. coli UNC from IL-10(-/-) mice. In addition, the inhibitor of vertebrate C-type lysozyme, Ivy, was upregulated on messenger RNA (mRNA) and protein level in E. coli Nissle from IL-10(-/-) mice compared with E. coli UNC from these mice. Higher expression of Ivy in E. coli Nissle correlated with an improved growth of this probiotic strain in the presence of lysozyme-ethylenediaminetetraacetic acid (EDTA). By overexpressing Ivy, we demonstrated that Ivy contributes to a higher lysozyme resistance of E. coli, supporting the role of Ivy as a potential fitness factor. However, deletion of Ivy did not alter the growth phenotype of E. coli Nissle in the presence of lysozyme-EDTA, suggesting the existence of additional lysozyme inhibitors that can take over the function of Ivy. PMID:23855897

  19. Kinetics of Schiff base on Escherichia coli by microcalorimetry

    Institute of Scientific and Technical Information of China (English)

    许名飞; 李新海; 万洪文; 刘义

    2003-01-01

    The influence of four kinds of Schiff bases on a strain of Escherichia coli was studied by microcalorimetry. Differences in their capabilities of suppressing the metabolism of this bacterium were observed. The results show that the extent and duration of the inhibitory effect on the metabolism as judged from the multiplication rate constant, k, varies with different Schiff bases.The multiplication rate constant k, of Escherichia coli (in log phase) in the presence of Mo-salicylioaldehyde-thiadizole, Mo-piperonaldehyde-thiosemicarbazone and Mo-3-methoxy-salicylicaldehyde-thiadizole decreases with the increase of concentrations of compounds c, and the relationships between k and c, maximum heat production rate Pm and c, peak time of growth curves tp and c are of linearity. For Mo-6-nitro-pieronalde-thiosemicarbazone, the multiplication rate constant is constant irrespective of variation in concentration. The sequence of antibiotic activity of Schiff base is: Mo-salicylioaldehyde-thiadizole>Mo-3-methoxy-salicylicaldehyde-thiadizole>Mo-piperonaldehyde-thiosemicarbazone> 6-nitro-pieronalde-thiosemicarbazone.

  20. Growth of the modeling of Escherichia coli in milk

    International Nuclear Information System (INIS)

    Escherichia coli is a contaminant potential of milk. Collective toxinfections implying the bacterium and milk were announced of share the world. However, no identified work proposed a mathematical expression of the growth of the bacterium in milk. The interest of such a step is however undeniable. Under specified conditions, the mathematical formulation of the growth provides the means of considering the population bacterial when the analyses cannot be carried out. It also makes it possible to test the negatiable instruments of the unfavourable circumstances supposed suchas chain breakage of cold on the development of the microbial charge. This work established mathematical expressions of the growth of Escherichia coli in milk for part of its range of temperature of growth suboptimale i.e. between 25 and 35 Deg C. It was not possible to generalize these expressions for predictions on all the range of temperature suboptimal. This work also made it possible to highlight a deviation of the behavoir of the bacterium compared to the model of Ratkowsky without however that it is not possible to provide a univocal explanantion of it. Varoius assumptions were put forth referring to either a singularity of the behavior of the bacterium or a skew of the value of its minimal temperature of growth

  1. Genetic determinants of heat resistance in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Ryan eMercer

    2015-09-01

    Full Text Available Escherichia coli AW1.7 is a heat resistant food isolate and the occurrence of pathogenic strains with comparable heat resistance may pose a risk to food safety. To identify the genetic determinants of heat resistance, 29 strains of E. coli that differed in their of heat resistance were analyzed by comparative genomics. Strains were classified as highly heat resistant strains, exhibiting a D60-value of more than 6 min; moderately heat resistant strains, exhibiting a D60-value of more than 1 min; or as heat sensitive. A ~14 kb genomic island containing 16 predicted open reading frames encoding putative heat shock proteins and proteases was identified only in highly heat resistant strains. The genomic island was termed the locus of heat resistance (LHR. This putative operon is flanked by mobile elements and possesses >99% sequence identity to genomic islands contributing to heat resistance in Cronobacter sakazakii and Klebsiella pneumoniae. An additional 41 LHR sequences with >87% sequence identity were identified in 11 different species of β- and γ-proteobacteria. Cloning of the full length LHR conferred high heat resistance to the heat sensitive E. coli AW1.7ΔpHR1 and DH5α. The presence of the LHR correlates perfectly to heat resistance in several species of Enterobacteriaceae and occurs at a frequency of 2% of all E. coli genomes, including pathogenic strains. This study suggests the LHR has been laterally exchanged among the β- and γ-proteobacteria and is a reliable indicator of high heat resistance in E. coli.

  2. Anaerobic respiration of Escherichia coli in the mouse intestine.

    Science.gov (United States)

    Jones, Shari A; Gibson, Terri; Maltby, Rosalie C; Chowdhury, Fatema Z; Stewart, Valley; Cohen, Paul S; Conway, Tyrrell

    2011-10-01

    The intestine is inhabited by a large microbial community consisting primarily of anaerobes and, to a lesser extent, facultative anaerobes, such as Escherichia coli, which we have shown requires aerobic respiration to compete successfully in the mouse intestine (S. A. Jones et al., Infect. Immun. 75:4891-4899, 2007). If facultative anaerobes efficiently lower oxygen availability in the intestine, then their sustained growth must also depend on anaerobic metabolism. In support of this idea, mutants lacking nitrate reductase or fumarate reductase have extreme colonization defects. Here, we further explore the role of anaerobic respiration in colonization using the streptomycin-treated mouse model. We found that respiratory electron flow is primarily via the naphthoquinones, which pass electrons to cytochrome bd oxidase and the anaerobic terminal reductases. We found that E. coli uses nitrate and fumarate in the intestine, but not nitrite, dimethyl sulfoxide, or trimethylamine N-oxide. Competitive colonizations revealed that cytochrome bd oxidase is more advantageous than nitrate reductase or fumarate reductase. Strains lacking nitrate reductase outcompeted fumarate reductase mutants once the nitrate concentration in cecal mucus reached submillimolar levels, indicating that fumarate is the more important anaerobic electron acceptor in the intestine because nitrate is limiting. Since nitrate is highest in the absence of E. coli, we conclude that E. coli is the only bacterium in the streptomycin-treated mouse large intestine that respires nitrate. Lastly, we demonstrated that a mutant lacking the NarXL regulator (activator of the NarG system), but not a mutant lacking the NarP-NarQ regulator, has a colonization defect, consistent with the advantage provided by NarG. The emerging picture is one in which gene regulation is tuned to balance expression of the terminal reductases that E. coli uses to maximize its competitiveness and achieve the highest possible population in

  3. Functional expression of adhesive peptides as fusions to Escherichia coli flagellin.

    Science.gov (United States)

    Westerlund-Wikström, B; Tanskanen, J; Virkola, R; Hacker, J; Lindberg, M; Skurnik, M; Korhonen, T K

    1997-11-01

    An expression system for studying epitopes of adhesion proteins based on fusion of gene fragments into fliC(H7) of Escherichia coli is described. We constructed the system by an in-frame insertion of DNA fragments encoding one, two or three of the fibronectin-binding D repeats present in the fibronectin-binding protein A (FnBPA) of Staphylococcus aureus, into the fliC(H7) gene region encoding the variable domain of the H7 flagellin. The constructs were expressed by in trans complementation in the E. coli strain JT1 which harbours knock-out mutations for the expression of FliC as well as of the mannoside-binding fimbrial adhesin. The resulting chimeric flagella, which contained 39, 77 or 115 heterologous amino acid residues, efficiently bound soluble and immobilized human plasma and cellular fibronectin, and the binding was most efficient with the flagella containing the three D repeats of FnBPA. The chimeric flagella bound to frozen sections of human kidney and to cultured human cells. Antibodies raised against the chimeric flagella bound to Protein A-deficient S. aureus cells and inhibited the binding of staphylococci to immobilized fibronectin. We also expressed peptides, ranging in size between 48 and 302 amino acids, of the collagen-binding YadA adhesin of Yersinia enterocolitica. A fragment of 302 amino acids representing the middle region of YadA was needed for collagen binding. Chimeric flagellar filaments expressing hundreds of intimately associated adhesive epitopes offer versatile tools to analyze adhesin-receptor interactions and functional epitopes of adhesion proteins. PMID:9514121

  4. Immobilizing live Escherichia coli for AFM studies of surface dynamics

    International Nuclear Information System (INIS)

    Atomic force microscopy (AFM) is a probe-based technique that permits high resolution imaging of live bacterial cells. However, stably immobilizing cells to withstand the probe-based lateral forces remains an obstacle in AFM mediated studies, especially those of live, rod shaped bacteria in nutrient media. Consequently, AFM has been under-utilized in the research of bacterial surface dynamics. The aim of the current study was to immobilize a less adherent Escherichia coli strain in a method that both facilitates AFM imaging in nutrient broth and preserves overall cell viability. Immobilization reagents and buffers were systematically evaluated and the cell membrane integrity was monitored in all sample preparations. As expected, the biocompatible gelatin coated surfaces facilitated stable cell attachment in lower ionic strength buffers, yet poorly immobilized cells in higher ionic strength buffers. In comparison, poly-L-lysine surfaces bound cells in both low and high ionic strength buffers. The benefit of the poly-L-lysine binding capacity was offset by the compromised membrane integrity exhibited by cells on poly-L-lysine surfaces. However, the addition of divalent cations and glucose to the immobilization buffer was found to mitigate this unfavorable effect. Ultimately, immobilization of E. coli cells on poly-L-lysine surfaces in a lower ionic strength buffer supplemented with Mg2+ and Ca2+ was determined to provide optimal cell attachment without compromising the overall cell viability. Cells immobilized in this method were stably imaged in media through multiple division cycles. Furthermore, permeability assays indicated that E. coli cells recover from the hypoosmotic stress caused by immobilization in low ionic strength buffers. Taken together, this data suggests that stable immobilization of viable cells on poly-L-lysine surfaces can be accomplished in lower ionic strength buffers that are supplemented with divalent cations for membrane stabilization while

  5. Immobilizing live Escherichia coli for AFM studies of surface dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Lonergan, N.E.; Britt, L.D.; Sullivan, C.J., E-mail: sullivcj@evms.edu

    2014-02-01

    Atomic force microscopy (AFM) is a probe-based technique that permits high resolution imaging of live bacterial cells. However, stably immobilizing cells to withstand the probe-based lateral forces remains an obstacle in AFM mediated studies, especially those of live, rod shaped bacteria in nutrient media. Consequently, AFM has been under-utilized in the research of bacterial surface dynamics. The aim of the current study was to immobilize a less adherent Escherichia coli strain in a method that both facilitates AFM imaging in nutrient broth and preserves overall cell viability. Immobilization reagents and buffers were systematically evaluated and the cell membrane integrity was monitored in all sample preparations. As expected, the biocompatible gelatin coated surfaces facilitated stable cell attachment in lower ionic strength buffers, yet poorly immobilized cells in higher ionic strength buffers. In comparison, poly-L-lysine surfaces bound cells in both low and high ionic strength buffers. The benefit of the poly-L-lysine binding capacity was offset by the compromised membrane integrity exhibited by cells on poly-L-lysine surfaces. However, the addition of divalent cations and glucose to the immobilization buffer was found to mitigate this unfavorable effect. Ultimately, immobilization of E. coli cells on poly-L-lysine surfaces in a lower ionic strength buffer supplemented with Mg{sup 2+} and Ca{sup 2+} was determined to provide optimal cell attachment without compromising the overall cell viability. Cells immobilized in this method were stably imaged in media through multiple division cycles. Furthermore, permeability assays indicated that E. coli cells recover from the hypoosmotic stress caused by immobilization in low ionic strength buffers. Taken together, this data suggests that stable immobilization of viable cells on poly-L-lysine surfaces can be accomplished in lower ionic strength buffers that are supplemented with divalent cations for membrane

  6. Mdt(A), a New Efflux Protein Conferring Multiple Antibiotic Resistance in Lactococcus lactis and Escherichia coli

    Science.gov (United States)

    Perreten, Vincent; Schwarz, Franziska V.; Teuber, Michael; Levy, Stuart B.

    2001-01-01

    The mdt(A) gene, previously designated mef214, from Lactococcus lactis subsp. lactis plasmid pK214 encodes a protein [Mdt(A) (multiple drug transporter)] with 12 putative transmembrane segments (TMS) that contain typical motifs conserved among the efflux proteins of the major facilitator superfamily. However, it also has two C-motifs (conserved in the fifth TMS of the antiporters) and a putative ATP-binding site. Expression of the cloned mdt(A) gene decreased susceptibility to macrolides, lincosamides, streptogramins, and tetracyclines in L. lactis and Escherichia coli, but not in Enterococcus faecalis or in Staphylococcus aureus. Glucose-dependent efflux of erythromycin and tetracycline was demonstrated in L. lactis and in E. coli. PMID:11257023

  7. [Improving 3-dehydroshikimate production by metabolically engineered Escherichia coli].

    Science.gov (United States)

    Yuan, Fei; Chen, Wujiu; Jia, Shiru; Wang, Qinhong

    2014-10-01

    In the aromatic amino acid biosynthetic pathway 3-dehydroshikimate (DHS) is a key intermediate. As a potent antioxidant and important feedstock for producing a variety of important industrial chemicals, such as adipate and vanillin, DHS is of great commercial value. Here, in this study, we investigated the effect of the co-expression of aroFFBR (3-deoxy-D-arabino-heptulosonate 7-phosphate synthase mutant with tyrosine feedback-inhibition resistance) and tktA (Transketolase A) at different copy number on the production of DHS. The increased copy number of aroFFBR and tktA would enhance the production of DHS by the fold of 2.93. In order to further improve the production of DHS, we disrupted the key genes in by-product pathways of the parent strain Escherichia coli AB2834. The triple knockout strain of ldhA, ackA-pta and adhE would further increase the production of DHS. The titer of DHS in shake flask reached 1.83 g/L, 5.7-fold higher than that of the parent strain E. coli AB2834. In 5-L fed-batch fermentation, the metabolically engineered strain produced 25.48 g/L DHS after 62 h. Metabolically engineered E. coli has the potential to further improve the production of DHS. PMID:25726580

  8. Recombinant expression of Streptococcus pneumoniae capsular polysaccharides in Escherichia coli

    Science.gov (United States)

    Kay, Emily J.; Yates, Laura E.; Terra, Vanessa S.; Cuccui, Jon; Wren, Brendan W.

    2016-01-01

    Currently, Streptococcus pneumoniae is responsible for over 14 million cases of pneumonia worldwide annually, and over 1 million deaths, the majority of them children. The major determinant for pathogenesis is a polysaccharide capsule that is variable and is used to distinguish strains based on their serotype. The capsule forms the basis of the pneumococcal polysaccharide vaccine (PPV23) that contains purified capsular polysaccharide from 23 serotypes, and the pneumococcal conjugate vaccine (PCV13), containing 13 common serotypes conjugated to CRM197 (mutant diphtheria toxin). Purified capsule from S. pneumoniae is required for pneumococcal conjugate vaccine production, and costs can be prohibitively high, limiting accessibility of the vaccine in low-income countries. In this study, we demonstrate the recombinant expression of the capsule-encoding locus from four different serotypes of S. pneumoniae within Escherichia coli. Furthermore, we attempt to identify the minimum set of genes necessary to reliably and efficiently express these capsules heterologously. These E. coli strains could be used to produce a supply of S. pneumoniae serotype-specific capsules without the need to culture pathogenic bacteria. Additionally, these strains could be applied to synthetic glycobiological applications: recombinant vaccine production using E. coli outer membrane vesicles or coupling to proteins using protein glycan coupling technology. PMID:27110302

  9. Fecal leukocytes in children infected with diarrheagenic Escherichia coli.

    Science.gov (United States)

    Mercado, Erik H; Ochoa, Theresa J; Ecker, Lucie; Cabello, Martin; Durand, David; Barletta, Francesca; Molina, Margarita; Gil, Ana I; Huicho, Luis; Lanata, Claudio F; Cleary, Thomas G

    2011-04-01

    The purpose of this study was to determine the presence and quantity of fecal leukocytes in children infected with diarrheagenic Escherichia coli and to compare these levels between diarrhea and control cases. We analyzed 1,474 stool samples from 935 diarrhea episodes and 539 from healthy controls of a cohort study of children younger than 2 years of age in Lima, Peru. Stools were analyzed for common enteric pathogens, and diarrheagenic E. coli isolates were studied by a multiplex real-time PCR. Stool smears were stained with methylene blue and read by a blinded observer to determine the number of polymorphonuclear leukocytes per high-power field (L/hpf). Fecal leukocytes at >10 L/hpf were present in 11.8% (110/935) of all diarrheal episodes versus 1.1% (6/539) in controls (P 10 L/hpf were present in 8.5% (18/212) of diarrhea versus 1.3% (2/157) of control samples (P 10 L/hpf) with an odds ratio (OR) of 4.1 (95% confidence interval [CI], 1.08 to 15.51; P < 0.05). Although diarrheagenic E. coli was isolated with similar frequencies in diarrhea and control samples, clearly it was associated with a more inflammatory response during symptomatic infection; however, in general, these pathogens elicited a mild inflammatory response. PMID:21325554

  10. Genomic islands of uropathogenic Escherichia coli contribute to virulence.

    Science.gov (United States)

    Lloyd, Amanda L; Henderson, Tiffany A; Vigil, Patrick D; Mobley, Harry L T

    2009-06-01

    Uropathogenic Escherichia coli (UPEC) strain CFT073 contains 13 large genomic islands ranging in size from 32 kb to 123 kb. Eleven of these genomic islands were individually deleted from the genome, and nine isogenic mutants were tested for their ability to colonize the CBA/J mouse model of ascending urinary tract infection. Three genomic island mutants (Delta PAI-aspV, Delta PAI-metV, and Delta PAI-asnT) were significantly outcompeted by wild-type CFT073 in the bladders and/or kidneys following transurethral cochallenge (P Delta c2518-15) was significantly outcompeted by wild-type CFT073 in cochallenge. Strains with mutations in a type VI secretion system within the PAI-metV island did not show attenuation. The attenuation of the PAI-metV island was localized to genes c3405-10, encoding a putative phosphotransferase transport system, which is common to UPEC and avian pathogenic E. coli strains but absent from E. coli K-12. We have shown that, in addition to encoding virulence genes, genomic islands contribute to the overall fitness of UPEC strain CFT073 in vivo. PMID:19329634

  11. Identification of Diarrheagenic Escherichia coli Strains from Avian Organic Fertilizers

    Directory of Open Access Journals (Sweden)

    Juan Puño-Sarmiento

    2014-08-01

    Full Text Available The Brazilian poultry industry generates large amounts of organic waste, such as chicken litter, which is often used in agriculture. Among the bacteria present in organic fertilizer are members of the Enterobacteriaceae family. The objective of this study was to detect the presence of diarrheagenic Escherichia coli (DEC strains in avian organic fertilizer, and assess the potential damage they can cause in humans due to antimicrobial resistance. The presence of DEC pathotypes and phylogenetic groups were detected by multiplex-PCR. Phenotypic assays, such as tests for adhesion, cytotoxicity activity, biofilm formation and especially antimicrobial susceptibility, were performed. Fifteen DEC strains from 64 E. coli were isolated. Among these, four strains were classified as enteropathogenic (EPEC; 6.2%, three strains as Shiga toxin-producing (STEC; 4.7%, 10 strains as enteroaggregative (EAEC; 12.5%, but two of these harbored the eaeA gene too. The low number of isolated strains was most likely due to the composting process, which reduces the number of microorganisms. These strains were able to adhere to HEp-2 and HeLa cells and produce Shiga-toxins and biofilms; in addition, some of the strains showed antimicrobial resistance, which indicates a risk of the transfer of resistance genes to human E. coli. These results showed that DEC strains isolated from avian organic fertilizers can cause human infections.

  12. Starved Escherichia coli preserve reducing power under nitric oxide stress.

    Science.gov (United States)

    Gowers, Glen-Oliver F; Robinson, Jonathan L; Brynildsen, Mark P

    2016-07-15

    Nitric oxide (NO) detoxification enzymes, such as NO dioxygenase (NOD) and NO reductase (NOR), are important to the virulence of numerous bacteria. Pathogens use these defense systems to ward off immune-generated NO, and they do so in environments that contain additional stressors, such as reactive oxygen species, nutrient deprivation, and acid stress. NOD and NOR both use reducing equivalents to metabolically deactivate NO, which suggests that nutrient deprivation could negatively impact their functionality. To explore the relationship between NO detoxification and nutrient deprivation, we examined the ability of Escherichia coli to detoxify NO under different levels of carbon source availability in aerobic cultures. We observed failure of NO detoxification under both carbon source limitation and starvation, and those failures could have arisen from inabilities to synthesize Hmp (NOD of E. coli) and/or supply it with sufficient NADH (preferred electron donor). We found that when limited quantities of carbon source were provided, NO detoxification failed due to insufficient NADH, whereas starvation prevented Hmp synthesis, which enabled cells to maintain their NADH levels. This maintenance of NADH levels under starvation was confirmed to be dependent on the absence of Hmp. Intriguingly, these data show that under NO stress, carbon-starved E. coli are better positioned with regard to reducing power to cope with other stresses than cells that had consumed an exhaustible amount of carbon. PMID:27207837

  13. 2DBase: 2D-PAGE database of Escherichia coli.

    Science.gov (United States)

    Vijayendran, Chandran; Burgemeister, Sebastian; Friehs, Karl; Niehaus, Karsten; Flaschel, Erwin

    2007-11-23

    We present a web-based integrated proteome database, termed 2DBase of Escherichia coli which was designed to store, compare, analyse, and retrieve various information obtained by 2D polyacrylamide gel electrophoresis and mass spectrometry. The main objectives of this database are (1) to provide the features for query and data-mining applications to access the stored proteomics data (2) to efficiently compare the specific protein spots present in the comparable proteome maps and (3) to analyse the data with the integrated classification for cellular functions of gene products of E. coli. This database currently contains 12 gels consisting of 1185 protein spots information in which 723 proteins were identified and annotated. Individual protein spots in the existing gels can be displayed, queried, analyzed, and compared in a tabular format based on various functional categories enabling quick and subsequent analyses. Our database satisfies the requirement to be a federated 2-DE database by accomplishing various tasks through a web interface providing access to a relational database system. The 2DBase of E. coli database can be accessed at http://2dbase.techfak.uni-bielefeld.de/. PMID:17904107

  14. Escherichia coli bacteria detection by using graphene-based biosensor.

    Science.gov (United States)

    Akbari, Elnaz; Buntat, Zolkafle; Afroozeh, Abdolkarim; Zeinalinezhad, Alireza; Nikoukar, Ali

    2015-10-01

    Graphene is an allotrope of carbon with two-dimensional (2D) monolayer honeycombs. A larger detection area and higher sensitivity can be provided by graphene-based nanosenor because of its 2D structure. In addition, owing to its special characteristics, including electrical, optical and physical properties, graphene is known as a more suitable candidate compared to other materials used in the sensor application. A novel model employing a field-effect transistor structure using graphene is proposed and the current-voltage (I-V) characteristics of graphene are employed to model the sensing mechanism. This biosensor can detect Escherichia coli (E. coli) bacteria, providing high levels of sensitivity. It is observed that the graphene device experiences a drastic increase in conductance when exposed to E. coli bacteria at 0-10(5) cfu/ml concentration. The simple, fast response and high sensitivity of this nanoelectronic biosensor make it a suitable device in screening and functional studies of antibacterial drugs and an ideal high-throughput platform which can detect any pathogenic bacteria. Artificial neural network and support vector regression algorithms have also been used to provide other models for the I-V characteristic. A satisfactory agreement has been presented by comparison between the proposed models with the experimental data. PMID:26435280

  15. Metabolic engineering of Escherichia coli to produce zeaxanthin.

    Science.gov (United States)

    Li, Xi-Ran; Tian, Gui-Qiao; Shen, Hong-Jie; Liu, Jian-Zhong

    2015-04-01

    Zeaxanthin is a high-value carotenoid that is used in nutraceuticals, cosmetics, food, and animal feed industries. Zeaxanthin is chemically synthesized or purified from microorganisms as a natural product; however, increasing demand requires development of alternative sources such as heterologous biosynthesis by recombinant bacteria. For this purpose, we molecularly engineered Escherichia coli to optimize the synthesis of zeaxanthin from lycopene using fusion protein-mediated substrate channeling as well as by the introduction of tunable intergenic regions. The tunable intergenic regions approach was more efficient compared with protein fusion for coordinating expression of lycopene β-cyclase gene crtY and β-carotene 3-hydroxylase gene crtZ. The influence of the substrate channeling effect suggests that the reaction catalyzed by CrtZ is the rate-limiting step in zeaxanthin biosynthesis. Then Pantoea ananatis, Pantoea agglomerans and Haematococcus pluvialis crtZ were compared. Because P. ananatis crtZ is superior to that of P. agglomerans or H. pluvialis for zeaxanthin production, we used it to generate a recombinant strain of E. coli BETA-1 containing pZSPBA-2(P37-crtZPAN) that produced higher amounts of zeaxanthin (11.95 ± 0.21 mg/g dry cell weight) than other engineered E. coli strains described in the literature. PMID:25533633

  16. Properties of a Clostridium thermocellum Endoglucanase Produced in Escherichia coli.

    Science.gov (United States)

    Schwarz, W H; Gräbnitz, F; Staudenbauer, W L

    1986-06-01

    A cellulase gene of Clostridium thermocellum was transferred to Escherichia coli by molecular cloning with bacteriophage lambda and plasmid vectors and shown to be indentical with the celA gene. The celA gene product was purified from extracts of plasmid-bearing E. coli cells by heat treatment and chromatography on DEAE-Trisacryl. It was characterized as a thermophilic endo-beta-1,4-glucanase, the properties of which closely resemble those of endoglucanase A previously isolated from C. thermocellum supernatants. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis the enzyme purified from E. coli exhibited two protein bands with molecular weights of 49,000 and 52,000. It had a temperature optimum at 75 degrees C and was stable for several hours at 60 degrees C. Endoglucanase activity was optimal between pH 5.5 and 6.5. The enzyme was insensitive against end product inhibition by glucose and cellobiose and remarkably resistant to the denaturing effects of detergents and organic solvents. It was capable of degrading, in addition to cellulosic substrates, glucans with alternating beta-1,4 and beta-1,3 linkages such as barley beta-glucan and lichenan. PMID:16347088

  17. Multiple Antimicrobial Resistance of Escherichia coli Isolated from Chickens in Iran

    OpenAIRE

    Reza Talebiyan; Mehdi Kheradmand; Faham Khamesipour; Mohammad Rabiee-Faradonbeh

    2014-01-01

    Antimicrobial agents are used extremely in order to reduce the great losses caused by Escherichia coli infections in poultry industry. In this study, 318 pathogenic Escherichia coli (APEC) strains isolated from commercial broiler flocks with coli-septicemia were examined for antimicrobials of both veterinary and human significance by disc diffusion method. Multiple resistances to antimicrobial agents were observed in all the isolates. Resistance to the antibiotics was as follows: Tylosin (88....

  18. Plasmid profiling of multidrug resistant Escherichia coli strains isolated from urinary tract infection patients

    OpenAIRE

    Sabin Khadgi; Uddhav Timilsina; Basudha Shrestha

    2013-01-01

    Introduction- Urinary tract infection is a common community-acquired bacterial disease. Escherichia coli is reported to be the major cause of urinary tract infection. Aim & Objective- The study was conducted with the aim of determining the antibiotic resistance pattern and plasmid profile of multidrug resistant Escherichia coli isolated from Urinary Tract Infection patients. Materials and Method- Antibiotic susceptibility tests were performed against E. coli following the protocol for the Kir...

  19. Detection of Escherichia Coli O157:H7 in Fecal Samples in Meat Goats

    Science.gov (United States)

    Mobley, Ray; Madden, Uford; Brooks-Walter, Alexis

    2004-01-01

    Studies have reported the isolation of Escherichia coli (E. coli)O157:H7 from pork, lamb and poultry products, and from other animals including deer, horses, dogs, birds and humans. There is limited or no information on the presence of the organism in goats. The objectives of this study were to determine if E. coli O157:H7 was naturally occurring…

  20. Mechanisms of antibiotic resistance to enrofloxacin in uropathogenic Escherichia coli in dog

    Science.gov (United States)

    Escherichia coli (E. coli) urinary tract infections (UTIs) are becoming a serious problem both for pets and humans (zoonosis) due to the close contact and to the increasing resistance to antibiotics. Canine E. coli represents a good experimental model useful to study this pathology. Moreover, as des...

  1. Diet, fecal microbiome and Escherichia coli O157:H7 shedding in beef Cattle

    Science.gov (United States)

    Shiga-toxigenic Escherichia coli, such as E. coli O157:H7, are foodborne zoonotic pathogens that can cause severe illness and death in humans. The gastrointestinal tract of ruminant animals has been identified as a primary habitat for E. coli O157:H7, and in cattle the terminal gastrointestinal tra...

  2. Colonization with Extraintestinal Pathogenic Escherichia coli among Nursing Home Residents and Its Relationship to Fluoroquinolone Resistance

    OpenAIRE

    Maslow, Joel N.; Lautenbach, Ebbing; Glaze, Thomas; Bilker, Warren; Johnson, James R.

    2004-01-01

    In a cross-sectional fecal prevalence survey involving 49 residents of a Veterans Affairs nursing home, 59% of subjects were colonized with extraintestinal pathogenic Escherichia coli (ExPEC), 22% were colonized with adhesin-positive E. coli, and 51% were colonized with fluoroquinolone-resistant E. coli. Among 80 unique isolates, adhesins correlated negatively and aerobactin correlated positively with fluoroquinolone resistance.

  3. Characterization of pathogenic Escherichia coli isolated from humans in Austria : phenotypes, toxin gene types and epidemiology

    NARCIS (Netherlands)

    Wagner, M; Allerberger, F; Manafi, M; Lindner, G; Friedrich, A W; Sonntag, A-K; Foissy, H

    2004-01-01

    One hundred and ten clinical Escherichia coli isolates of serovar O157 (n = 102) and O26 (n = 8) were characterized for the presence of putative virulence genes by PCR. All but one of these isolates contained the eae gene. The EHEC-hly gene could be detected in all E. coli O157 and in 50% of E. coli

  4. Dietary interactions and interventions affecting Escherichia coli 0157 colonization and shedding in cattle

    Science.gov (United States)

    Escherichia coli O157 is an important foodborne pathogen affecting human health and the beef cattle industry. Contamination of carcasses at slaughter is correlated to the prevalence of E. coli O157 in cattle feces. Many associations have been made between dietary factors and E. coli O157 prevalenc...

  5. Escherichia coli O157:H7, diet, and fecal microbiome in beef cattle

    Science.gov (United States)

    Shiga-toxigenic Escherichia coli, such as E. coli O157:H7, are foodborne zoonotic pathogens that can cause severe illness and death in humans. The gastrointestinal tract of ruminant animals has been identified as a primary habitat for E. coli O157:H7, and in cattle the terminal gastrointestinal tra...

  6. Biosynthesis of two quercetin O-diglycosides in Escherichia coli.

    Science.gov (United States)

    An, Dae Gyun; Yang, So Mi; Kim, Bong Gyu; Ahn, Joong-Hoon

    2016-06-01

    Various flavonoid glycosides are found in nature, and their biological activities are as variable as their number. In some cases, the sugar moiety attached to the flavonoid modulates its biological activities. Flavonoid glycones are not easily synthesized chemically. Therefore, in this study, we attempted to synthesize quercetin 3-O-glucosyl (1→2) xyloside and quercetin 3-O-glucosyl (1→6) rhamnoside (also called rutin) using two uridine diphosphate-dependent glycosyltransferases (UGTs) in Escherichia coli. To synthesize quercetin 3-O-glucosyl (1→2) xyloside, sequential glycosylation was carried out by regulating the expression time of the two UGTs. AtUGT78D2 was subcloned into a vector controlled by a Tac promoter without a lacI operator, while AtUGT79B1 was subcloned into a vector controlled by a T7 promoter. UDP-xyloside was supplied by concomitantly expressing UDP-glucose dehydrogenase (ugd) and UDP-xyloside synthase (UXS) in the E. coli. Using these strategies, 65.0 mg/L of quercetin 3-O-glucosyl (1→2) xyloside was produced. For the synthesis of rutin, one UGT (BcGT1) was integrated into the E. coli chromosome and the other UGT (Fg2) was expressed in a plasmid along with RHM2 (rhamnose synthase gene 2). After optimization of the initial cell concentration and incubation temperature, 119.8 mg/L of rutin was produced. The strategies used in this study thus show promise for the synthesis of flavonoid diglucosides in E. coli. PMID:26931782

  7. Isobutyraldehyde production from Escherichia coli by removing aldehyde reductase activity

    Directory of Open Access Journals (Sweden)

    Rodriguez Gabriel M

    2012-06-01

    Full Text Available Abstract Background Increasing global demand and reliance on petroleum-derived chemicals will necessitate alternative sources for chemical feedstocks. Currently, 99% of chemical feedstocks are derived from petroleum and natural gas. Renewable methods for producing important chemical feedstocks largely remain unaddressed. Synthetic biology enables the renewable production of various chemicals from microorganisms by constructing unique metabolic pathways. Here, we engineer Escherichia coli for the production of isobutyraldehyde, which can be readily converted to various hydrocarbons currently derived from petroleum such as isobutyric acid, acetal, oxime and imine using existing chemical catalysis. Isobutyraldehyde can be readily stripped from cultures during production, which reduces toxic effects of isobutyraldehyde. Results We adopted the isobutanol pathway previously constructed in E. coli, neglecting the last step in the pathway where isobutyraldehyde is converted to isobutanol. However, this strain still overwhelmingly produced isobutanol (1.5 g/L/OD600 (isobutanol vs 0.14 g/L/OD600 (isobutyraldehyde. Next, we deleted yqhD which encodes a broad-substrate range aldehyde reductase known to be active toward isobutyraldehyde. This strain produced isobutanol and isobutyraldehyde at a near 1:1 ratio, indicating further native isobutyraldehyde reductase (IBR activity in E. coli. To further eliminate isobutanol formation, we set out to identify and remove the remaining IBRs from the E. coli genome. We identified 7 annotated genes coding for IBRs that could be active toward isobutyraldehyde: adhP, eutG, yiaY, yjgB, betA, fucO, eutE. Individual deletions of the genes yielded only marginal improvements. Therefore, we sequentially deleted all seven of the genes and assessed production. The combined deletions greatly increased isobutyraldehyde production (1.5 g/L/OD600 and decreased isobutanol production (0.4 g/L/OD600. By assessing production by

  8. Adherent-Invasive Escherichia coli Phenotype Displayed by Intestinal Pathogenic E. coli Strains from Cats, Dogs, and Swine ▿

    OpenAIRE

    Martinez-Medina, Margarita; Garcia-Gil, Jesus; Barnich, Nicolas; Lothar H Wieler; Ewers, Christa

    2011-01-01

    The adherent-invasive Escherichia coli (AIEC) pathotype, which has been associated with Crohn's disease, shows similar traits to human and animal extraintestinal pathogenic E. coli (ExPEC) with respect to their phylogenetic origin and virulence gene profiles. Here, we demonstrate that animal ExPEC strains generally do not share the AIEC phenotype. In contrast, this phenotype is very frequent among animal intestinal pathogenic E. coli (InPEC) strains, particularly of feline and canine origin, ...

  9. Collective motion in an active suspension of Escherichia coli bacteria

    International Nuclear Information System (INIS)

    We investigate experimentally the emergence of collective motion in the bulk of an active suspension of Escherichia coli bacteria. When increasing the concentration from a dilute to a semi-dilute regime, we observe a continuous crossover from a dynamical cluster regime to a regime of ‘bio-turbulence’ convection patterns. We measure a length scale characterizing the collective motion as a function of the bacteria concentration. For bacteria fully supplied with oxygen, the increase of the correlation length is almost linear with concentration and at the largest concentrations tested, the correlation length could be as large as 24 bacterial body sizes (or 7–8 when including the flagella bundle). In contrast, under conditions of oxygen shortage the correlation length saturates at a value of around 7 body lengths. (paper)

  10. Structure of the Cyclomodulin Cif from Pathogenic Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Y.; Jubelin, G; Taieb, F; Nougayrède, J; Oswald, E; Stebbins, C

    2008-01-01

    Bacterial pathogens have evolved a sophisticated arsenal of virulence factors to modulate host cell biology. Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) use a type III protein secretion system (T3SS) to inject microbial proteins into host cells. The T3SS effector cycle inhibiting factor (Cif) produced by EPEC and EHEC is able to block host eukaryotic cell-cycle progression. We present here a crystal structure of Cif, revealing it to be a divergent member of the superfamily of enzymes including cysteine proteases and acetyltransferases that share a common catalytic triad. Mutation of these conserved active site residues abolishes the ability of Cif to block cell-cycle progression. Finally, we demonstrate that irreversible cysteine protease inhibitors do not abolish the Cif cytopathic effect, suggesting that another enzymatic activity may underlie the biological activity of this virulence factor.

  11. Selection of quiescent Escherichia coli with high metabolic activity.

    Science.gov (United States)

    Sonderegger, Marco; Schümperli, Michael; Sauer, Uwe

    2005-01-01

    Sustained metabolic activity in non-growing, quiescent cells can increase the operational life-span of bio-processes and improve process economics by decoupling production from cell growth. Because of the ill-defined molecular nature of this phenotype, we developed selection protocols for the evolution of quiescent Escherichia coli mutants that exhibit high metabolic activity in ammonium starvation-induced stationary phase. The best enrichment procedures were continuously or discontinuously fed ammonium-limited chemostat cultures with a very low dilution rate of 0.03 h(-1). After 40 generations of selection, improved mutants with up to doubled catabolic rates in stationary phase were isolated. The metabolically most active clones were identified by screening for high specific glucose uptake rates during ammonium starvation-induced stationary phase in deep-well microtiter plates. PMID:15721805

  12. Overexpression of Soluble Human Thymosin Alpha 1 in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Pei-Fu CHEN; Hong-Ying ZHANG; Geng-Feng FU; Gen-Xing XU; Ya-Yi HOU

    2005-01-01

    Synthesized gene of human thymosin alpha 1 (Tα1) was inserted into pET-28a, pET-9c,pThioHis B, pGEX-2T or pBV222 and then inductively expressed in strains of Escherichia coli. Among the five expression systems, the BL21/pET-28a system provides the highest expression level of fusion protein in a soluble form, which is up to 70% of total expressed bacterial proteins as visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The resulting fusion protein purified through nickel affinity chromatography accounts for 2.53% of the wet bacterial pellet weight and reaches 94.5% purity by SDS-PAGE. These results indicate the potential of this expression system for high-throughput production of recombinant Tα1.

  13. Theoretical Prediction of Disrupted Min Oscillation in Flattened Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Jeff B Schulte

    Full Text Available The dynamics of the Min-protein system help Escherichia coli regulate the process of cell division by identifying the center of the cell. While this system exhibits robust bipolar oscillations in wild-type cell shapes, recent experiments have shown that when the cells are mechanically deformed into wide, flattened out, irregular shapes, the spatial regularity of these oscillations breaks down. We employ widely used stochastic and deterministic models of the Min system to simulate cells with flattened shapes. The deterministic model predicts strong bipolar oscillations, in contradiction with the experimentally observed behavior, while the stochastic model, which is based on the same reaction-diffusion equations, predicts more spatially irregular oscillations. We further report simulations of flattened but more symmetric shapes, which suggest that the flattening and lateral expansion may contribute as much to the irregular oscillation behavior as the asymmetry of the cell shapes.

  14. A series of template plasmids for Escherichia coli genome engineering.

    Science.gov (United States)

    Deb, Shalini S; Reshamwala, Shamlan M S; Lali, Arvind M

    2016-06-01

    Metabolic engineering strategies often employ multi-copy episomal vectors to overexpress genes. However, chromosome-based overexpression is preferred as it avoids the use of selective pressure and reduces metabolic burden on the cell. We have constructed a series of template plasmids for λ Red-mediated Escherichia coli genome engineering. The template plasmids allow construction of genome integrating cassettes that can be used to integrate single copies of DNA sequences at predetermined sites or replace promoter regions. The constructed cassettes provide flexibility in terms of expression levels achieved and antibiotics used for selection, as well as allowing construction of marker-free strains. The modular design of the template plasmids allows replacement of genetic parts to construct new templates. Gene integration and promoter replacement using the template plasmids are illustrated. PMID:27071533

  15. De novo biosynthesis of Gastrodin in Escherichia coli.

    Science.gov (United States)

    Bai, Yanfen; Yin, Hua; Bi, Huiping; Zhuang, Yibin; Liu, Tao; Ma, Yanhe

    2016-05-01

    Gastrodin, a phenolic glycoside, is the key ingredient of Gastrodia elata, a notable herbal plant that has been used to treat various conditions in oriental countries for centuries. Gastrodin is extensively used clinically for its sedative, hypnotic, anticonvulsive and neuroprotective properties in China. Gastrodin is usually produced by plant extraction or chemical synthesis, which has many disadvantages. Herein, we report unprecedented microbial synthesis of gastrodin via an artificial pathway. A Nocardia carboxylic acid reductase, endogenous alcohol dehydrogenases and a Rhodiola glycosyltransferase UGT73B6 transformed 4-hydroxybenzoic acid, an intermediate of ubiquinone biosynthesis, into gastrodin in Escherichia coli. Pathway genes were overexpressed to enhance metabolic flux toward precursor 4-hydroxybenzyl alcohol. Furthermore, the catalytic properties of the UGT73B6 toward phenolic alcohols were improved through directed evolution. The finally engineered strain produced 545mgl(-1) gastrodin in 48h. This work creates a new route to produce gastrodin, instead of plant extractions and chemical synthesis. PMID:26804288

  16. Sugar metabolism in transketolase mutants of Escherichia coli.

    Science.gov (United States)

    Josephson, B L; Fraenkel, D G

    1974-06-01

    This paper continues the description of transketolase mutants of Escherichia coli; they are absolutely unable to grow on pentoses, but slightly "leaky" with respect to their aromatic requirement (B. L. Josephson and D. G. Fraenkel, 1969). Several experiments have explored the degree of leakiness and shown it to be low. There is little conversion of radioactive xylose to carbon dioxide. The labeling of ribose in cells grown on [1-(14)C]glucose and [2-(14)C]glucose accords with its origin being chiefly by the oxidative pathway. A mutant lacking both transketolase and gluconate-6-phosphate dehydrogenase has been constructed; it requires supplementation with pentose. Pentoses are inhibitory to growth of transketolase mutants, but high levels of pentose phosphates do not accumulate in this situation. Several experimental results are suggestive of regulation of metabolic flow in the oxidative branch of the hexose monophosphate shunt. PMID:4597996

  17. SOS response induces persistence to fluoroquinolones in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Tobias Dörr

    2009-12-01

    Full Text Available Bacteria can survive antibiotic treatment without acquiring heritable antibiotic resistance. We investigated persistence to the fluoroquinolone ciprofloxacin in Escherichia coli. Our data show that a majority of persisters to ciprofloxacin were formed upon exposure to the antibiotic, in a manner dependent on the SOS gene network. These findings reveal an active and inducible mechanism of persister formation mediated by the SOS response, challenging the prevailing view that persisters are pre-existing and formed purely by stochastic means. SOS-induced persistence is a novel mechanism by which cells can counteract DNA damage and promote survival to fluoroquinolones. This unique survival mechanism may be an important factor influencing the outcome of antibiotic therapy in vivo.

  18. Detergent (sodium dodecyl sulfate) shock proteins in Escherichia coli

    International Nuclear Information System (INIS)

    The protein composition of Escherichia coli W3110 grown in the presence and absence of 5% sodium dodecyl sulfate (SDS) was examined by two-dimensional gel electrophoresis. In SDS-grown cells, at least 4 proteins were turned on, 13 were turned off, 15 were elevated, and 15 were depressed. The 19 unique and elevated SDS-induced spots constituted 7.91% of the total 35S-labeled protein. There was no apparent overlap between these 19 detergent (SDS) stress proteins and those of other known bacterial stress responses. The detergent stress stimulon is a distinct and independent stimulon. Its physiological relevance probably derives from the presence of bile salts in animal gastrointestinal tracts

  19. Evidence of histidine phosphorylation in isocitrate lyase from Escherichia coli

    International Nuclear Information System (INIS)

    Escherichia coli isocitrate lyase can be phosphorylated in vitro in an ATP-dependent reaction. Partially purified extracts were incubated with γ-32P-ATP and analyzed by two-dimensional polyacrylamide gel electrophoresis followed by a Western blot and autoradiography. Radioactivity was associated with the lyase only when blotting was performed under alkaline conditions. This suggests that phosphate groups are attached to the lyase via an acid-labile P-N bond rather than a more stable P-O bond. Treatment of the lyase with diethyl pyrocarbonate, a histidine modifying agent, blocks incorporation of 32P-phosphate. Treatment with phosphoramidate, a histidine phosphorylating agent, alters the isoelectric point of the lyase suggesting that the enzyme can be phosphorylated at histidine residues. Loss of catalytic activity after treatment with potato acid phosphatase indicates that isocitrate lyase activity may be modulated by phosphorylation

  20. Signaling and sensory adaptation in Escherichia coli chemoreceptors: 2015 update.

    Science.gov (United States)

    Parkinson, John S; Hazelbauer, Gerald L; Falke, Joseph J

    2015-05-01

    Motile Escherichia coli cells track gradients of attractant and repellent chemicals in their environment with transmembrane chemoreceptor proteins. These receptors operate in cooperative arrays to produce large changes in the activity of a signaling kinase, CheA, in response to small changes in chemoeffector concentration. Recent research has provided a much deeper understanding of the structure and function of core receptor signaling complexes and the architecture of higher-order receptor arrays, which, in turn, has led to new insights into the molecular signaling mechanisms of chemoreceptor networks. Current evidence supports a new view of receptor signaling in which stimulus information travels within receptor molecules through shifts in the dynamic properties of adjoining structural elements rather than through a few discrete conformational states. PMID:25834953

  1. Uropathogenic Escherichia coli Epigenetically Manipulate Host Cell Death Pathways.

    Science.gov (United States)

    Zhang, Zhengguo; Wang, Ming; Eisel, Florian; Tchatalbachev, Svetlin; Chakraborty, Trinad; Meinhardt, Andreas; Bhushan, Sudhanshu

    2016-04-01

    Urinary tract infections caused by uropathogenic Escherichia coli (UPEC) pathovars belong to the most frequent infections in human. It is well established that UPEC can subvert innate immune responses, but the role of UPEC in interfering with host cell death pathways is not known. Here, we show that UPEC abrogates activation of the host cell prosurvival protein kinase B signaling pathway, which results in the activation of mammalian forkhead box O (FOXO) transcription factors. Although FOXOs were localized in the nucleus and showed increased DNA-binding activity, no change in the expression levels of FOXO target genes were observed. UPEC can suppress BIM expression induced by LY249002, which results in attenuation of caspase 3 activation and blockage of apoptosis. Mechanistically, BIM expression appears to be epigenetically silenced by a decrease in histone 4 acetylation at the BIM promoter site. Taken together, these results suggest that UPEC can epigenetically silence BIM expression, a molecular switch that prevents apoptosis. PMID:26621912

  2. Chromosome segregation control by Escherichia coli ObgE GTPase.

    Science.gov (United States)

    Foti, James J; Persky, Nicole S; Ferullo, Daniel J; Lovett, Susan T

    2007-07-01

    Escherichia coli cells depleted of the conserved GTPase, ObgE, show early chromosome-partitioning defects and accumulate replicated chromosomes in which the terminus regions are colocalized. Cells lacking ObgE continue to initiate replication, with a normal ratio of the origin to terminus. Localization of the SeqA DNA binding protein, normally seen as punctate foci, however, was disturbed. Depletion of ObgE also results in cell filamentation, with polyploid DNA content. Depletion of ObgE did not cause lethality, and cells recovered fully after expression of ObgE was restored. We propose a model in which ObgE is required to license chromosome segregation and subsequent cell cycle events. PMID:17578452

  3. Initiation of Replication in Escherichia coli

    DEFF Research Database (Denmark)

    Frimodt-Møller, Jakob

    The circular chromosome of Escherichia coli is replicated by two replisomes assembled at the unique origin and moving in the opposite direction until they meet in the less well defined terminus. The key protein in initiation of replication, DnaA, facilitates the unwinding of double-stranded DNA to...... single-stranded DNA in oriC. Although DnaA is able to bind both ADP and ATP, DnaA is only active in initiation when bound to ATP. Although initiation of replication, and the regulation of this, is thoroughly investigated it is still not fully understood. The overall aim of the thesis was to investigate...... the regulation of initiation, the effect on the cell when regulation fails, and if regulation was interlinked to chromosomal organization. This thesis uncovers that there exists a subtle balance between chromosome replication and reactive oxygen species (ROS) inflicted DNA damage. Thus, failure in...

  4. Functional biosynthesis of an allophycocyan beta subunit in Escherichia coli.

    Science.gov (United States)

    Ge, Baosheng; Sun, Haixiang; Feng, Yang; Yang, Jinying; Qin, Song

    2009-03-01

    Allophycocyanin is a phycobiliprotein with various biological and pharmacological properties. An expression vector was constructed using CpeS as the bilin lyase for the allophycocyanin beta subunit, resulting in overexpression of a fluorescent allophycocyanin beta-subunit in Escherichia coli. A high-density cell culture was developed using a continuous feeding strategy. After 16 h of culture, the dry cell density reached 21.4 g l(-1), the expression of the allophycocyanin beta-subunit was 0.86 g l(-1) broth, and the relative chromoprotein yield was 81.4%. The recombinant protein showed spectral features similar to native allophycocyanin, which provide an efficient methodology for large-scale production of this valuable fluorescent protein. PMID:19269586

  5. Renal abscess due to Escherichia coli in a child

    Directory of Open Access Journals (Sweden)

    V P Baradkar

    2011-01-01

    Full Text Available Among the various intraabdominal abscesses, renal abscess is a rare entity, especially in children and accounts for a number of cases of "missed diagnoses." Drainage of pus and appropriate antibiotic therapy is the gold standard for treatment. Here we report a case of left renal abscess in a 6-year-old female child secondary to renal calculus. The patient presented with abdominal pain and mild fever for three months and the diagnosis was made by X-ray in the kidney, ureter and bladder (KUB region, intravenous pyelography and ultrasonography of the abdomen. Escherichia coli was isolated from pus obtained by percutaneous drainage under sonographic guidance. The patient responded to intra-venous ceftriaxone, amikacin, and percutaneous drainage.

  6. Escherichia coli activity characterization using a laser dynamic speckle technique

    CERN Document Server

    Ramírez-Miquet, Evelio E; Contreras-Alarcón, Orestes R

    2012-01-01

    The results of applying a laser dynamic speckle technique to characterize bacterial activity are presented. The speckle activity was detected in two-compartment Petri dishes. One compartment was inoculated and the other one was left as a control blank. The speckled images were processed by the recently reported temporal difference method. Three inoculums of 0.3, 0.5, and 0.7 McFarland units of cell concentration were tested; each inoculum was tested twice for a total of six experiments. The dependences on time of the mean activity, the standard deviation of activity and other descriptors of the speckle pattern evolution were calculated for both the inoculated compartment and the blank. In conclusion the proposed dynamic speckle technique allows characterizing the activity of Escherichia coli bacteria in solid medium.

  7. Analysis of resynthesis tracts in repaired Escherichia coli deoxyribonucleic acid

    International Nuclear Information System (INIS)

    Excision repair of ultraviolet radiation-induced damage in a wild-type strain of Escherichia coli has been examined, using two methods for characterizing the resynthesis step of the repair process. Comparison of data obtained after both isopycnic analysis of repaired deoxyribonucleic acid and sedimentation velocity analysis of deoxyribonucleic acid after selective photolysis of bromouracil-containing repaired regions has shown that the repaired deoxyribonucleic acid molecules contain a semicontinuous distribution of sizes of repair tracts. Further analysis of our data suggests two major classes of repair patches, one about 20 to 40 nucleotides in length, and the other containing 1600 to 2000 nucleotides. Under the conditions employed, approximately 2 to 10% of the fully repaired regions are long repair patches

  8. Improvement of escherichia coli for lysine overproduction through mutagenesis

    International Nuclear Information System (INIS)

    Bacterial isolates of Escherichia coli were obtained from the irrigation channel water. One of the isolates designated SW30 NIAB produced glutamic acid in cane molasses medium and was selected for further improvement for lysine overproduction. The cells of this strain were treated with a dose of 100 u/ g/ml of NTG(N-methyl-N-nitro-N-Nitrosoguanidine), for 90 minutes. From the cell population (3x108 cells/ml) exposed to NTG, only 1-2 percent cells survived and produced colonies. Independent colonies, 100 of them that survived the dose, were secured and subcultured. These were further screened against AEC (S-(2-aminoethyl)-L-cysteine) resistance on minimal agar medium MM-12. Among these 100 colonies, 10 proved resistant to AEC at a dose of 1000 ug/ml, and out of 10, three were lysine producers and produced 0.1-0.5 gm/ltr of lysine in L-6 medium. (author)

  9. Role of verocytotoxigenic Escherichia coli in the swine production chain

    Directory of Open Access Journals (Sweden)

    Laura Ercoli

    2015-06-01

    Full Text Available Shiga toxin-producing Escherichia coli (STEC can cause severe clinical diseases in humans, such as haemorrhagic colitis (HC and haemolytic-uremic syndrome (HUS. Although ruminants, primarily cattle, have been suggested as typical reservoirs of STEC, many food products of other origins, including pork products, have been confirmed as vehicles for STEC transmission. Only in rare cases, pork consumption is associated with severe clinical symptoms caused by high pathogenic STEC strains. However, in these outbreaks, it is unknown whether the contamination of food products occurs during swine processing or via cross-contamination from foodstuffs of different sources. In swine, STEC plays an important role in the pathogenesis of oedema disease. In particular a Shiga toxin subtype, named stx2e, it is considered as a key factor involved in the damage of swine endothelial cells. On the contrary, stx2e-producing Escherichia coli has rarely been isolated in humans, and usually only from asymptomatic carriers or from patients with mild symptoms, such as uncomplicated diarrhoea. In fact, the presence of gene stx2e, encoding for stx2e, has rarely been reported in STEC strains that cause HUS. Moreover, stx2e-producing STEC isolated from humans and pigs were found to differ in serogroup, their virulence profile and interaction with intestinal epithelial cells. Because of the limited epidemiologic data of STEC in swine and the increasing role of non-O157 STEC in human illnesses, the relationship between swine STEC and human disease needs to be further investigated.

  10. DAYA HAMBAT FRAKSINASI EKSTRAK SEMBUNG DELAN (SPHAERANTUS INDICUS L TERHADAP BAKTERI ESCHERICIA COLI DAN STAPHYLOCOCCUS AUREUS

    Directory of Open Access Journals (Sweden)

    IDA BAGUS GEDE DARMAYASA

    2008-12-01

    Full Text Available A research entitled "Inhibitid activity of plant fractination extract of Sembung Delan (Sphaeranthus indicus L. to Eschericia coli and Staphylococus aureus bacterial was carried aut to find the active of plant extract that responsible for bactericidal agent. This research used absorbance disc method to determine inhibitid fractionation extratc of Sembung Delan to growth of Eschericia coli and Staphylococus aureus bacterial. Results of this study showed that the crude extract of Sembung Delan inhibited the growth of Eschericia coli and Staphylococus aureus on Muller- Hinton medium, indicated by the formation of inhibition zone around the disc loaded with plant extract at concentration of 10,000 ppm, 20,000 ppm, 30,000 ppm, 40,000 ppm, and 50,000 ppm, with diamtre of 10mm, llmm, 12mm, 13mm and 16 mm respectively to S. aureus, forE. coli crude extract at concentration of 10,000 ppm, 20,000 ppm, 30,000 ppm, 40,000 ppm, and 50,000 ppm using diametre each of 12 mm, 13 mm, 15 mm, 17 mm and 19 mm respectively . From 17 fractions obtained from fractionation, fraction No. Vm (eluted with ethyl acetate:hexan with Rf value of 0,9 ; 0,8 ; 0,7 ; 0,68 ; and 0,62, fraction No. DC (eluted with etihil acetate : hexan with Rf value of : 0,98, ; 0,94 ; and 0,82, fraction No. XV (eluted with ethyl acetate 100% Rf value of : 0.03; 0.23; 0.35 and fraction No. XVI (eluted with ethyl acetate 100% with Rf value of: 0.03; 0.14; 0.17; 0.21, effectivity inhibited the growth of test bacterial.

  11. Efficient production of Staphylococcus simulans lysostaphin in a benchtop bioreactor by recombinant Escherichia coli.

    Science.gov (United States)

    Szweda, Piotr; Gorczyca, Grzegorz; Filipkowski, Pawel; Zalewska, Magdalena; Milewski, Slawomir

    2014-01-01

    Lysostaphin is an enzyme with bactericidal activity against Staphylococcus aureus and other staphylococcal species. In spite of many advantages and promising results of preliminary research, the enzyme is still not widely used in medicine, veterinary medicine, or as a food preservative. One of the most important factors limiting application of the enzyme in clinical or technological practice is the high cost of its production. In this study we have determined the optimal conditions for lysostaphin production in a 5-L batch bioreactor. The enzyme production was based on a heterologous, Escherichia coli expression system designated as pBAD2Lys and constructed earlier in our laboratory. An evident influence of physicochemical conditions of the process (areation, pH and temperature) and composition of the growing media on the amount and activity of produced enzyme was noticed. Efficiency of production of about 13,000 U/L has been achieved in the optimal conditions of the production process: low aeration (400 rpm of mechanical stirrer), pH 6, and temperature 37°C in classical LB medium. Further, about twofold improvement in the production efficiency of the enzyme was achieved as a result of modification of composition of growing media. Finally, more than 80,000 units of lysostaphin were obtained from one (batch) bioreactor with 3 L of culture of E. coli TOP10F' transformed with pBAD2Lys plasmid. To the best of our knowledge, this is the most efficient method of production of recombinant lysostaphin in E. coli expression systems described to date. PMID:24320237

  12. Evaluation of Petrifilm™ Select E. coli Count Plate medium to discriminate antimicrobial resistant Escherichia coli

    Directory of Open Access Journals (Sweden)

    Jensen Lars

    2008-09-01

    Full Text Available Abstract Background Screening and enumeration of antimicrobial resistant Escherichia coli directly from samples is needed to identify emerging resistant clones and obtain quantitative data for risk assessment. Aim of this study was to evaluate the performance of 3M™ Petrifilm™ Select E. coli Count Plate (SEC plate supplemented with antimicrobials to discriminate antimicrobial-resistant and non-resistant E. coli. Method A range of E. coli isolates were tested by agar dilution method comparing the Minimal Inhibitory Concentration (MIC for eight antimicrobials obtained by Mueller-Hinton II agar, MacConkey agar and SEC plates. Kappa statistics was used to assess the levels of agreement when classifying strains as resistant, intermediate or susceptible. Results SEC plate showed that 74% of all strains agreed within ± 1 log2 dilution when comparing MICs with Mueller-Hinton II media. High agreement levels were found for gentamicin, ampicillin, chloramphenicol and cefotaxime, resulting in a kappa value of 0.9 and 100% agreement within ± 1 log2 dilution. Significant variances were observed for oxytetracycline and sulphamethoxazole. Further tests showed that the observed discrepancy in classification of susceptibility to oxytetracycline by the two media could be overcome when a plate-dependent breakpoint of 64 mg/L was used for SEC plates. For sulphamethoxazole, SEC plates provided unacceptably high MICs. Conclusion SEC plates showed good agreement with Mueller-Hinton II agar in MIC studies and can be used to screen and discriminate resistant E. coli for ampicillin, cephalothin, streptomycin, chloramphenicol, cefotaxime and gentamicin using CLSI standardized breakpoints, but not for sulphamethoxazole. SEC plates can also be used to discriminate oxytetracycline-resistant E. coli if a plate-dependent breakpoint value of 64 mg/L is used.

  13. Invariant distribution of promoter activities in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Alon Zaslaver

    2009-10-01

    Full Text Available Cells need to allocate their limited resources to express a wide range of genes. To understand how Escherichia coli partitions its transcriptional resources between its different promoters, we employ a robotic assay using a comprehensive reporter strain library for E. coli to measure promoter activity on a genomic scale at high-temporal resolution and accuracy. This allows continuous tracking of promoter activity as cells change their growth rate from exponential to stationary phase in different media. We find a heavy-tailed distribution of promoter activities, with promoter activities spanning several orders of magnitude. While the shape of the distribution is almost completely independent of the growth conditions, the identity of the promoters expressed at different levels does depend on them. Translation machinery genes, however, keep the same relative expression levels in the distribution across conditions, and their fractional promoter activity tracks growth rate tightly. We present a simple optimization model for resource allocation which suggests that the observed invariant distributions might maximize growth rate. These invariant features of the distribution of promoter activities may suggest design constraints that shape the allocation of transcriptional resources.

  14. Molecular evolution of the Escherichia coli chromosome. IV. Sequence comparisons.

    Science.gov (United States)

    Milkman, R; Bridges, M M

    1993-03-01

    DNA sequences have been compared in a 4,400-bp region for Escherichia coli K12 and 36 ECOR strains. Discontinuities in degree of similarity, previously inferred, are confirmed in detail. Three clonal frames are described on the basis of the present local high-resolution data, as well as previous analyses of restriction fragment length polymorphism (RFLP) and of multilocus enzyme electrophoresis (MLEE) covering small regions more widely dispersed on the chromosome. These three approaches show important consistency. The data illustrate the fact that, in the limited context of intraspecific genomic sequence variation, clonality and homology are synonymous. Two estimable quantitative properties are defined: recency of common ancestry (the reciprocal of the log10 of the number of generations since the most recent common ancestor), and the number of nucleotide pairs over which a given recency of common ancestry applies. In principle, these parameters are measures of the degree and physical extent of homology. The small size of apparent recombinational replacements, together with the observation that they occasionally occur in discontinuous series, raises the question of whether they result from the superimposition of replacements of much larger size (as expected from an elementary interpretation of conjugation and transduction in experimental E. coli systems) or via an alternative mechanism. Length polymorphisms of several sorts are described. PMID:8095913

  15. Increased cytoplasm viscosity hampers aggregate polar segregation in Escherichia coli.

    Science.gov (United States)

    Oliveira, Samuel M D; Neeli-Venkata, Ramakanth; Goncalves, Nadia S M; Santinha, João A; Martins, Leonardo; Tran, Huy; Mäkelä, Jarno; Gupta, Abhishekh; Barandas, Marilia; Häkkinen, Antti; Lloyd-Price, Jason; Fonseca, José M; Ribeiro, Andre S

    2016-02-01

    In Escherichia coli, under optimal conditions, protein aggregates associated with cellular aging are excluded from midcell by the nucleoid. We study the functionality of this process under sub-optimal temperatures from population and time lapse images of individual cells and aggregates and nucleoids within. We show that, as temperature decreases, aggregates become homogeneously distributed and uncorrelated with nucleoid size and location. We present evidence that this is due to increased cytoplasm viscosity, which weakens the anisotropy in aggregate displacements at the nucleoid borders that is responsible for their preference for polar localisation. Next, we show that in plasmolysed cells, which have increased cytoplasm viscosity, aggregates are also not preferentially located at the poles. Finally, we show that the inability of cells with increased viscosity to exclude aggregates from midcell results in enhanced aggregate concentration in between the nucleoids in cells close to dividing. This weakens the asymmetries in aggregate numbers between sister cells of subsequent generations required for rejuvenating cell lineages. We conclude that the process of exclusion of protein aggregates from midcell is not immune to stress conditions affecting the cytoplasm viscosity. The findings contribute to our understanding of E. coli's internal organisation and functioning, and its fragility to stressful conditions. PMID:26507787

  16. Composite analysis for Escherichia coli at coastal beaches

    Science.gov (United States)

    Bertke, E.E.

    2007-01-01

    At some coastal beaches, concentrations of fecal-indicator bacteria can differ substantially between multiple points at the same beach at the same time. Because of this spatial variability, the recreational water quality at beaches is sometimes determined by stratifying a beach into several areas and collecting a sample from each area to analyze for the concentration of fecal-indicator bacteria. The average concentration of bacteria from those points is often used to compare to the recreational standard for advisory postings. Alternatively, if funds are limited, a single sample is collected to represent the beach. Compositing the samples collected from each section of the beach may yield equally accurate data as averaging concentrations from multiple points, at a reduced cost. In the study described herein, water samples were collected at multiple points from three Lake Erie beaches and analyzed for Escherichia coli on modified mTEC agar (EPA Method 1603). From the multiple-point samples, a composite sample (n = 116) was formed at each beach by combining equal aliquots of well-mixed water from each point. Results from this study indicate that E. coli concentrations from the arithmetic average of multiple-point samples and from composited samples are not significantly different (t = 1.59, p = 0.1139) and yield similar measures of recreational water quality; additionally, composite samples could result in a significant cost savings.

  17. Light induced DEP for immobilizing and orienting Escherichia coli bacteria

    Science.gov (United States)

    Miccio, Lisa; Marchesano, Valentina; Mugnano, Martina; Grilli, Simonetta; Ferraro, Pietro

    2016-01-01

    Manipulating bacteria and understanding their behavior when interacting with different substrates are of fundamental importance for patterning, detection, and any other topics related to health-care, food-enterprise, etc. Here, we adopt an innovative dielectrophoretic (DEP) approach based on electrode-free DEP for investigating smart but simple strategies for immobilization and orientation of bacteria. Escherichia coli DH5-alpha strain has been selected as subject of the study. The light induced DEP is achieved through ferroelectric iron-doped lithium niobate crystals used as substrates. Due to the photorefractive (PR) property of such material, suitable light patterns allow writing spatial-charges-distribution inside its volume and the resultant electric fields are able to immobilize E. coli on the surface. The experiments showed that, after laser irradiation, about 80% of bacteria is blocked and oriented along a particular direction on the crystals within an area of few square centimeters. The investigation presented here could open the way for detection or patterning applications based on a new driving mechanism. Future perspectives also include the possibility to actively switch by light the DEP forces, through the writing/erasing characteristic of PR fields, to dynamically control biofilm spatial structure and arrangement.

  18. Outbreaks of virulent diarrheagenic Escherichia coli - are we in control?

    Directory of Open Access Journals (Sweden)

    Werber Dirk

    2012-02-01

    Full Text Available Abstract Shiga toxin-producing Escherichia coli (STEC are the most virulent diarrheagenic E. coli known to date. They can be spread with alarming ease via food as exemplified by a large sprout-borne outbreak of STEC O104:H4 in 2011 that was centered in northern Germany and affected several countries. Effective control of such outbreaks is an important public health task and necessitates early outbreak detection, fast identification of the outbreak vehicle and immediate removal of the suspected food from the market, flanked by consumer advice and measures to prevent secondary spread. In our view, opportunities to improve control of STEC outbreaks lie in early clinical suspicion for STEC infection, timely diagnosis of all STEC at the serotype-level and integrating molecular subtyping information into surveillance systems. Furthermore, conducting analytical studies that supplement patients' imperfect food history recall and performing, as an investigative element, product tracebacks, are pivotal but underutilized tools for successful epidemiologic identification of the suspected vehicle in foodborne outbreaks. As a corollary, these tools are amenable to tailor microbiological testing of suspected food. Please see related article: http://www.biomedcentral.com/1741-7015/10/12

  19. Efflux transporter engineering markedly improves amorphadiene production in Escherichia coli.

    Science.gov (United States)

    Zhang, Congqiang; Chen, Xixian; Stephanopoulos, Gregory; Too, Heng-Phon

    2016-08-01

    Metabolic engineering aims at altering cellular metabolism to produce valuable products at high yields and titers. Achieving high titers and productivity can be challenging if final products are largely accumulated intracellularly. A potential solution to this problem is to facilitate the export of these substances from cells by membrane transporters. Amorphadiene, the precursor of antimalarial drug artemisinin, is known to be secreted from Escherichia coli overexpressing the biosynthetic pathway. In order to assess the involvement of various endogenous efflux pumps in amorphadiene transport, the effects of single gene deletion of 16 known multidrug-resistant membrane efflux transporters were examined. The outer membrane protein TolC was found to be intimately involved in amorphadiene efflux. The overexpression of tolC together with ABC family transporters (macAB) or MFS family transporters (emrAB or emrKY) enhanced amorphadiene titer by more than threefold. In addition, the overexpression of transporters in the lipopolysaccharide transport system (msbA, lptD, lptCABFG) was found to improve amorphadiene production. As efflux transporters often have a wide range of substrate specificity, the multiple families of transporters were co-expressed and synergistic benefits were observed in amorphadiene production. This strategy of screening and then rationally engineering transporters can be used to improve the production of other valuable compounds in E. coli. Biotechnol. Bioeng. 2016;113: 1755-1763. © 2016 Wiley Periodicals, Inc. PMID:26804325

  20. Improvements In Ethanologenic Escherichia Coli and Klebsiella Oxytoca

    Energy Technology Data Exchange (ETDEWEB)

    Dr. David Nunn

    2010-09-30

    The current Verenium cellulosic ethanol process is based on the dilute-acid pretreatment of a biomass feedstock, followed by a two-stage fermentation of the pentose sugar-containing hydrolysate by a genetically modified ethanologenic Escherichia coli strain and a separate simultaneous saccharification-fermentation (SSF) of the cellulosic fraction by a genetically modified ethanologenic Klebsiella oxytoca strain and a fungal enzyme cocktail. In order to reduce unit operations and produce a fermentation beer with higher ethanol concentrations to reduce distillation costs, we have proposed to develop a simultaneous saccharification co-fermentation (SScF) process, where the fermentation of the pentose-containing hydrolysate and cellulosic fraction occurs within the same fermentation vessel. In order to accomplish this goal, improvements in the ethanologens must be made to address a number of issues that arise, including improved hydrolysate tolerance, co-fermentation of the pentose and hexose sugars and increased ethanol tolerance. Using a variety of approaches, including transcriptomics, strain adaptation, metagenomics and directed evolution, this work describes the efforts of a team of scientists from Verenium, University of Florida, Massachusetts Institute of Technology and Genomatica to improve the E. coli and K. oxytoca ethanologens to meet these requirements.

  1. Subversion of Host Innate Immunity by Uropathogenic Escherichia coli.

    Science.gov (United States)

    Olson, Patrick D; Hunstad, David A

    2016-01-01

    Uropathogenic Escherichia coli (UPEC) cause the majority of community-onset urinary tract infections (UTI) and represent a major etiologic agent of healthcare-associated UTI. Introduction of UPEC into the mammalian urinary tract evokes a well-described inflammatory response, comprising pro-inflammatory cytokines and chemokines as well as cellular elements (neutrophils and macrophages). In human UTI, this inflammatory response contributes to symptomatology and provides means for diagnosis by standard clinical testing. Early in acute cystitis, as demonstrated in murine models, UPEC gains access to an intracellular niche that protects a population of replicating bacteria from arriving phagocytes. To ensure the establishment of this protected niche, UPEC employ multiple strategies to attenuate and delay the initiation of host inflammatory components, including epithelial secretion of chemoattractants. Recent work has also revealed novel mechanisms by which UPEC blunts neutrophil migration across infected uroepithelium. Taken together, these attributes distinguish UPEC from commensal and nonpathogenic E. coli strains. This review highlights the unique immune evasion and suppression strategies of this bacterial pathogen and offers directions for further study; molecular understanding of these mechanisms will inform the development of adjunctive, anti-virulence therapeutics for UTI. PMID:26742078

  2. Structure of CFA/I fimbriae from enterotoxigenic Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yong-Fu; Poole, Steven; Nishio, Kazuya; Jang, Ken; Rasulova, Fatima; McVeigh, Annette; Savarino, Stephen J.; Xia, Di; Bullitt, Esther; (BU-M); (NIH); (NMRC)

    2009-10-21

    Adhesion pili (fimbriae) play a critical role in initiating the events that lead to intestinal colonization and diarrheal disease by enterotoxigenic Escherichia coli (ETEC), an E. coli pathotype that inflicts an enormous global disease burden. We elucidate atomic structures of an ETEC major pilin subunit, CfaB, from colonization factor antigen I (CFA/I) fimbriae. These data are used to construct models for 2 morphological forms of CFA/I fimbriae that are both observed in vivo: the helical filament into which it is typically assembled, and an extended, unwound conformation. Modeling and corroborative mutational data indicate that proline isomerization is involved in the conversion between these helical and extended forms. Our findings affirm the strong structural similarities seen between class 5 fimbriae (from bacteria primarily causing gastrointestinal disease) and class 1 pili (from bacteria that cause urinary, respiratory, and other infections) in the absence of significant primary sequence similarity. They also suggest that morphological and biochemical differences between fimbrial types, regardless of class, provide structural specialization that facilitates survival of each bacterial pathotype in its preferred host microenvironment. Last, we present structural evidence for bacterial use of antigenic variation to evade host immune responses, in that residues occupying the predicted surface-exposed face of CfaB and related class 5 pilins show much higher genetic sequence variability than the remainder of the pilin protein.

  3. Biosynthesis of fluorescent cyanobacterial allophycocyanin trimer in Escherichia coli.

    Science.gov (United States)

    Liu, Shaofang; Chen, Yingjie; Lu, Yandu; Chen, Huaxin; Li, Fuchao; Qin, Song

    2010-08-01

    Allophycocyanin (APC), a cyanobacterial photosynthetic phycobiliprotein, functions in energy transfer as a light-harvesting protein. One of the prominent spectroscopic characteristics of APC is a strong red-shift in the absorption and emission maxima when monomers are assembled into a trimer. Previously, holo-APC alpha and beta subunits (holo-ApcA and ApcB) were successfully synthesized in Escherichia coli. In this study, both holo-subunits from Synechocystis sp. PCC 6803 were co-expressed in E. coli, and found to self-assemble into trimers. The recombinant APC trimer was purified by metal affinity and size-exclusion chromatography, and had a native structure identical to native APC, as determined by characteristic spectroscopic measurements, fluorescence quantum yield, tryptic digestion analysis, and molecular weight measurements. Combined with results from a study in which only the monomer was formed, our results indicate that bilin synthesis and the subsequent attachment to apo-subunits are important for the successful assembly of APC trimers. This is the first study to report on the assembly of recombinant ApcA and ApcB into a trimer with native structure. Our study provides a promising method for producing better fluorescent tags, as well as a method to facilitate the genetic analysis of APC trimer assembly and biological function. PMID:20607408

  4. Association between antimicrobial consumption and resistance in Escherichia coli.

    Science.gov (United States)

    Bergman, Miika; Nyberg, Solja T; Huovinen, Pentti; Paakkari, Pirkko; Hakanen, Antti J

    2009-03-01

    During a 9-year study period from 1997 through 2005, the association between antimicrobial resistance rates in Escherichia coli and outpatient antimicrobial consumption was investigated in 20 hospital districts in Finland. A total of 754,293 E. coli isolates, mainly from urine samples, were tested for antimicrobial resistance in 26 clinical microbiology laboratories. The following antimicrobials were studied: ampicillin, amoxicillin-clavulanate, cephalosporins, fluoroquinolones, trimethoprim, trimethoprim-sulfamethoxazole, pivmecillinam, and nitrofurantoin. We applied a protocol used in earlier studies in which the level of antimicrobial consumption over 1 year was compared with the level of resistance in the next year. Statistically significant associations were found for nitrofurantoin use versus nitrofurantoin resistance (P < 0.0001), cephalosporin use versus nitrofurantoin resistance (P = 0.0293), amoxicillin use versus fluoroquinolone resistance (P = 0.0031), and fluoroquinolone use versus ampicillin resistance (P = 0.0046). Interestingly, we found only a few associations between resistance and antimicrobial consumption. The majority of the associations studied were not significant, including the association between fluoroquinolone use and fluoroquinolone resistance. PMID:19104012

  5. Scalable purification of Bacillus anthracis protective antigen from Escherichia coli.

    Science.gov (United States)

    Gwinn, William; Zhang, Mei; Mon, Sandii; Sampey, Darryl; Zukauskas, David; Kassebaum, Corby; Zmuda, Jonathan F; Tsai, Amos; Laird, Michael W

    2006-01-01

    The anthrax toxin consists of three proteins, protective antigen (PA), lethal factor, and edema factor that are produced by the Gram-positive bacterium, Bacillus anthracis. Current vaccines against anthrax use PA as their primary component. In this study, we developed a scalable process to produce and purify multi-gram quantities of highly pure, recombinant PA (rPA) from Escherichia coli. The rPA protein was produced in a 50-L fermentor and purified to >99% purity using anion-exchange, hydrophobic interaction, and hydroxyapatite chromatography. The final yield of purified rPA from medium cell density fermentations resulted in approximately 2.7 g of rPA per kg of cell paste (approximately 270 mg/L) of highly pure, biologically active rPA protein. The results presented here exhibit the ability to generate multi-gram quantities of rPA from E. coli that may be used for the development of new anthrax vaccines and anthrax therapeutics. PMID:15935696

  6. Pattern Formation of Bacterial Colonies by Escherichia coli

    Science.gov (United States)

    Tokita, Rie; Katoh, Takaki; Maeda, Yusuke; Wakita, Jun-ichi; Sano, Masaki; Matsuyama, Tohey; Matsushita, Mitsugu

    2009-07-01

    We have studied the morphological diversity and change in bacterial colonies, using the bacterial species Escherichia coli, as a function of both agar concentration Ca and nutrient concentration Cn. We observed various colony patterns, classified them into four types by pattern characteristics and established a morphological diagram by dividing it into four regions. They are regions A [diffusion-limited aggregation (DLA)-like], B (Eden-like), C (concentric-ring), and D (fluid-spreading). In particular, we have observed a concentric-ring colony growth for E. coli. We focused on the periodic growth in region C and obtained the following results: (i) A colony grows cyclically with the growing front repeating an advance (migration phase) and a momentary rest (consolidation phase) alternately. (ii) The growth width L and the bulge width W in one cycle decrease asymptotically to certain values, when Ca is increased. (iii) L does not depend on Cn, while W is an increasing function of Cn. Plausible mechanisms are proposed to explain the experimental results, by comparing them with those obtained for other bacterial species such as Proteus mirabilis and Bacillus subtilis.

  7. Secretion of Alpha-Hemolysin by Escherichia coli Disrupts Tight Junctions in Ulcerative Colitis Patients

    OpenAIRE

    Mirsepasi-Lauridsen, Hengameh Chloé; Du, Zhengyu; Struve, Carsten; Charbon, Godefroid; Karczewski, Jurgen; Krogfelt, Karen Angeliki; Petersen, Andreas Munk; Wells, Jerry M

    2016-01-01

    Objectives: The potential of Escherichia coli (E. coli) isolated from inflammatory bowel disease (IBD) patients to damage the integrity of the intestinal epithelium was investigated. Methods: E. coli strains isolated from patients with ulcerative colitis (UC) and healthy controls were tested for virulence capacity by molecular techniques and cytotoxic assays and transepithelial electric resistance (TER). E. coli isolate p19A was selected, and deletion mutants were created for alpha-hemolysin ...

  8. The Association of Virulence Determinants of Uropathogenic Escherichia coli With Antibiotic Resistance

    OpenAIRE

    Sara Asadi; Mohammad Kargar; Kavous Solhjoo; Akram Najafi; Sadegh Ghorbani-Dalini

    2014-01-01

    Background: The emergence of antimicrobial resistant strains of Escherichia coli has raised considerable interest in understanding the diversity and epidemiology of E. coli infections in humans. Virulence factors of E. coli determine the specific infections caused by this microorganism. Objectives: This study aimed to determine the prevalence of eight E. coli virulence factors and their association with antimicrobial resistance in bacteria isolated from patients with urinary tract infecti...

  9. Relative effects of bacterial and protozoan predators on survival of Escherichia coli in estuarine water samples.

    OpenAIRE

    McCambridge, J; McMeekin, T A

    1980-01-01

    The relative effect of protozoan and bacterial predators on the survival of Escherichia coli in estuarine water samples was examined. Predacious protozoa exerted their major influence on E. coli destruction during the first 2 days of a 10-day-decline period. Inhibition of protozoa after day 2 had little effect on E. coli survival. Bacterial predators also contributed to E. coli destruction but in natural estuarine water samples were maintained at lower levels due to "grazing" by predacious pr...

  10. Involvement of Focal Adhesion Kinase in Escherichia coli Invasion of Human Brain Microvascular Endothelial Cells

    OpenAIRE

    Reddy, Marpadga A; Wass, Carol A.; Kim, Kwang Sik; Schlaepfer, David D.; Prasadarao, Nemani V.

    2000-01-01

    Escherichia coli K1 traversal across the blood-brain barrier is an essential step in the pathogenesis of neonatal meningitis. We have previously shown that invasive E. coli promotes the actin rearrangement of brain microvascular endothelial cells (BMEC), which constitute a lining of the blood-brain barrier, for invasion. However, signal transduction mechanisms involved in E. coli invasion are not defined. In this report we show that tyrosine kinases play a major role in E. coli invasion of hu...

  11. A Survey for Escherichia coli Virulence Factors in Asymptomatic Free-Ranging Parrots

    OpenAIRE

    André Becker Saidenberg; Neiva Maria Robaldo Guedes; Gláucia Helena Fernandes Seixas; Mariangela da Costa Allgayer; Erica Pacífico de Assis; Luis Fabio Silveira; Priscilla Anne Melville; Nilson Roberti Benites

    2012-01-01

    Parrots in captivity are frequently affected by Escherichia coli (E. coli) infections. The objective of this study was to collect information on the carrier state for E. coli pathotypes in asymptomatic free-ranging parrots. Cloacal swabs were collected from nestlings of Hyacinth, Lear’s macaws and Blue-fronted Amazon parrots and tested by polymerase chain reaction (PCR) for virulence factors commonly found in enteropathogenic, avian pathogenic, and uropathogenic E. coli strains. In total, 44 ...

  12. Production of pili, hemolysin and siderophores in the urinary isolates of Escherichia coli

    OpenAIRE

    Marković Tatjana; Šmitran Aleksandra; Petković Miroslav

    2013-01-01

    Introduction. Escherichia coli (E. coli) are the most frequent cause of the urinary tract infections. Uropathogenic E. coli (UPEC) produce virulence factors which enable them to survive in the urinary tract and cause an infection. Objective. The objective of this study was to determine phenotype characterization of E. coli isolated from outpatients’ urine in the region of Banja Luka over three-year period. In line with the objective, the following research tasks were set up: determining...

  13. Vergleichende geno- und phänotypische Charakterisierung von Escherichia coli aus Menschen, Hausschweinen und Wildtieren

    OpenAIRE

    Frömmel, Ulrike

    2014-01-01

    Escherichia (E.) coli ist als kommensales Bakterium ein wichtiger Bestandteil des Mikrobioms von Säugern, jedoch zudem der häufigste Infektionserreger des Menschen. Entsprechend des Infektionsortes werden intestinal (InPEC) und extraintestinal pathogene E. coli (ExPEC) unterschieden. Die Pathogenese von E. coli-Infektionen ist durch Virulenzfaktoren determiniert, welche von jeweils spezifischen virulenzassoziierten Genen (inVAGs und exVAGs) kodiert werden. Häufig werden exVAGs auch in E. coli...

  14. Detection and Characterization of Diarrheagenic Escherichia coli from Young Children in Hanoi, Vietnam

    OpenAIRE

    Nguyen, Trung Vu; Le Van, Phung; Le Huy, Chinh; Gia, Khanh Nguyen; Weintraub, Andrej

    2005-01-01

    Diarrhea continues to be one of the most common causes of morbidity and mortality among infants and children in developing countries. Escherichia coli is an emerging agent among pathogens that cause diarrhea. The development of a highly applicable technique for the detection of different categories of diarrheagenic E. coli is important. We have used multiplex PCR by combining eight primer pairs specific for enteroaggregative E. coli (EAEC), enteroinvasive E. coli (EIEC), enterohemorrhagic E. ...

  15. Estimating Escherichia coli loads in streams based on various physical, chemical, and biological factors

    OpenAIRE

    Dwivedi, Dipankar; Mohanty, Binayak P.; Lesikar, Bruce J.

    2013-01-01

    Microbes have been identified as a major contaminant of water resources. Escherichia coli (E. coli) is a commonly used indicator organism. It is well recognized that the fate of E. coli in surface water systems is governed by multiple physical, chemical, and biological factors. The aim of this work is to provide insight into the physical, chemical, and biological factors along with their interactions that are critical in the estimation of E. coli loads in surface streams. There are various mo...

  16. Biosynthesis of odd-chain fatty alcohols in Escherichia coli.

    Science.gov (United States)

    Cao, Ying-Xiu; Xiao, Wen-Hai; Liu, Duo; Zhang, Jin-Lai; Ding, Ming-Zhu; Yuan, Ying-Jin

    2015-05-01

    Engineered microbes offer the opportunity to design and implement artificial molecular pathways for renewable production of tailored chemical commodities. Targeted biosynthesis of odd-chain fatty alcohols is very challenging in microbe, due to the specificity of fatty acids synthase for two-carbon unit elongation. Here, we developed a novel strategy to directly tailor carbon number in fatty aldehydes formation step by incorporating α-dioxygenase (αDOX) from Oryza sativa (rice) into Escherichia coli αDOX oxidizes Cn fatty acids (even-chain) to form Cn-1 fatty aldehydes (odd-chain). Through combining αDOX with fatty acyl-acyl carrier protein (-ACP) thioesterase (TE) and aldehyde reductase (AHR), the medium odd-chain fatty alcohols profile (C11, C13, C15) was firstly established in E. coli. Also, medium even-chain alkanes (C12, C14) were obtained by substitution of AHR to aldehyde decarbonylase (AD). The titer of odd-chain fatty alcohols was improved from 7.4mg/L to 101.5mg/L in tube cultivation by means of fine-tuning endogenous fatty acyl-ACP TE (TesA'), αDOX, AHRs and the genes involved in fatty acids metabolism pathway. Through high cell density fed-batch fermentation, a titer of 1.95g/L odd-chain fatty alcohols was achieved, which was the highest reported titer in E. coli. Our system has greatly expanded the current microbial fatty alcohols profile that provides a new brand solution for producing complex and desired molecules in microbes. PMID:25773521

  17. Inhibition of Escherichia coli ATP synthase by amphibian antimicrobial peptides.

    Science.gov (United States)

    Laughlin, Thomas F; Ahmad, Zulfiqar

    2010-04-01

    Previously melittin, the alpha-helical basic honey bee venom peptide, was shown to inhibit F(1)-ATPase by binding at the beta-subunit DELSEED motif of F(1)F(o)-ATP synthase. Herein, we present the inhibitory effects of the basic alpha-helical amphibian antimicrobial peptides, ascaphin-8, aurein 2.2, aurein 2.3, carein 1.8, carein 1.9, citropin 1.1, dermaseptin, maculatin 1.1, maganin II, MRP, or XT-7, on purified F(1) and membrane bound F(1)F(0)Escherichia coli ATP synthase. We found that the extent of inhibition by amphibian peptides is variable. Whereas MRP-amide inhibited ATPase essentially completely (approximately 96% inhibition), carein 1.8 did not inhibit at all (0% inhibition). Inhibition by other peptides was partial with a range of approximately 13-70%. MRP-amide was also the most potent inhibitor on molar scale (IC(50) approximately 3.25 microM). Presence of an amide group at the c-terminal of peptides was found to be critical in exerting potent inhibition of ATP synthase ( approximately 20-40% additional inhibition). Inhibition was fully reversible and found to be identical in both F(1)F(0) membrane preparations as well as in isolated purified F(1). Interestingly, growth of E. coli was abrogated in the presence of ascaphin-8, aurein 2.2, aurein 2.3, citropin 1.1, dermaseptin, magainin II-amide, MRP, MRP-amide, melittin, or melittin-amide but was unaffected in the presence of carein 1.8, carein 1.9, maculatin 1.1, magainin II, or XT-7. Hence inhibition of F(1)-ATPase and E. coli cell growth by amphibian antimicrobial peptides suggests that their antimicrobial/anticancer properties are in part linked to their actions on ATP synthase. PMID:20100509

  18. Probiotic Escherichia coli Nissle 1917 reduces growth, Shiga toxin expression, release and thus cytotoxicity of enterohemorrhagic Escherichia coli.

    Science.gov (United States)

    Mohsin, Mashkoor; Guenther, Sebastian; Schierack, Peter; Tedin, Karsten; Wieler, Lothar H

    2015-01-01

    Due to increased release or production of Shiga toxin by Enterohemorrhagic Escherichia coli (EHEC) after exposure to antimicrobial agents, the role of antimicrobial agents in EHEC mediated infections remains controversial. Probiotics are therefore rapidly gaining interest as an alternate therapeutic option. The well-known probiotic strain Escherichia coli Nissle 1917 (EcN) was tested in vitro to determine its probiotic effects on growth, Shiga toxin (Stx) gene expression, Stx amount and associated cytotoxicity on the most important EHEC strains of serotype O104:H4 and O157:H7. Following co-culture of EcN:EHEC in broth for 4 and 24 h, the probiotic effects on EHEC growth, toxin gene expression, Stx amount and cytotoxicity were determined using quantitative real time-PCR, Stx-ELISA and Vero cytotoxicity assays. Probiotic EcN strongly reduced EHEC numbers (cfu) of O104:H4 up to (68%) and O157:H7 to (72.2%) (pcoli strain MG1655 had no effect on EHEC growth. The level of stx expression was significantly down-regulated, particularly for the stx2a gene. The stx down-regulation in EcN co-culture was not due to reduced numbers of EHEC. A significant inhibition in Stx amounts and cytotoxicity were also observed in sterile supernatants of EcN:EHEC co-cultures. These findings indicate that probiotic EcN displays strong inhibitory effects on growth, Shiga toxin gene expression, amount and cytotoxicity of EHEC strains. Thus, EcN may be considered as a putative therapeutic candidate, in particular against EHEC O104:H4 and O157:H7. PMID:25465158

  19. Brote causado por Escherichia coli en Chalco, México Outbreak caused by Escherichia coli in Chalco, México

    Directory of Open Access Journals (Sweden)

    Iliana Alejandra Cortés-Ortiz

    2002-07-01

    Full Text Available Objetivo. Identificar el agente causal del brote de diarrea asociado con el desbordamiento del canal de aguas negras en Chalco. Material y métodos. Estudio retrospectivo y transversal, efectuado en el Instituto de Diagnóstico y Referencia Epidemiológicos (InDRE, de la Secretaría de Salud, con 1 550 hisopos rectales para el aislamiento e identificación bioquímica de V. cholerae y enterobacterias, obtenidos de la población del Valle de Chalco, que presentó diarrea y vómito durante el desastre natural acontecido el 31 de mayo de 2000. El análisis de los resultados se efectuó por la diferencia entre las proporciones de dos poblaciones (prueba de Ji cuadrada. Las cepas de E. coli se hibridaron por "colony blot" para los grupos ETEC, EIEC, EPEC y EHEC. Resultados. El 0.45% correspondió a Salmonella: S. agona, S. infantis, S. enteritidis, S. muenchen, S. typhimurium; 0.06% a Shigella flexneri 3a, y 76.6% a E. coli: 62.2% a ETEC (44.6 % con LT, 11.2% con ST, y 44.1% con ambas sondas, 0.84% a EIEC (sonda ial, 0.84% a EPEC (sonda bundle-forming pilus BFP, 0.08% a E. coli enterohemorrágica no-O157:H7 (sonda pCVD419, y 36.02% no hibridó. No se encontró asociación entre E. coli patógena con la edad y género. Conclusiones. Escherichia coli podría ser responsable del brote de diarrea. Es importante conocer el agente etiológico del brote para encaminar las estrategias en el estudio y control sanitario del mismo.Objective. To identify the etiologic agent responsible for a disease outbreak following an overflow of sewage water in Valle de Chalco, Mexico. Material and Methods. A retrospective cross-sectional study was carried out. Rectal samples were collected from the population of Chalco valley, who suffered from diarrhea and vomiting during a natural disaster that took place on May 31, 2000. The Instituto de Diagnóstico y Referencia Epidemiológicos (Epidemic Reference and Diagnosis Institute, InDRE, Ministry of Health, received 1521 rectal

  20. An Optimized Medium for Screening of L-Asparaginase production by Escherichia coli

    Directory of Open Access Journals (Sweden)

    Younes Ghasemi

    2008-01-01

    Full Text Available Purified L-asparaginase II from Escherichia coli has been supplied and employed in the acute leukemia and other malignant neoplasms chemotherapy. L-asparaginase II gene (ansB in E. coli is under regulation and certain conditions is needed for expression of this gene. In this investigation ,the various concentrations of modified M9 medium ingredients and various carbon source were tested to optimize the medium for expression and identification of L-asparaginase in E. coli. Finally a semi-quantitative plate assay for L-asparaginase producing Escherichia coli is reported.

  1. Hygiene Sanitasi Pengolahan Makanan Dan Pemeriksaan Escherichia Coli (E.Coli) Pada Pecel Yang Dijual Di Pasar Petisah Tahun 2015

    OpenAIRE

    Lubis, Nur Hasanah

    2015-01-01

    Pecel is a fast food consist of boiled vegetables and served with peanut chili sauce as a mixture. The seller is used prepare and serve pecel with hands directy. It causes pecel have a hazard contamination by bacteria Escherichia Coli (E.coli). E.coli presence in source water or food is definitely an indication of human fecal contamination and the presence of E.coli shows a sign which is not good sanitation practices to water and food. The objective of this research is to know about hygien...

  2. The Antibiotic Susceptibility Patterns of Uropathogenic Escherichia Coli, With Special Reference to the Fluoroquinolones

    OpenAIRE

    Shariff V A, Abdul Rahaman; Shenoy M, Suchitra; Yadav, Taruna; M, Radhakrishna

    2013-01-01

    Context: The emergence of drug resistance to trimethoprim-sulfamethoxazole, the penicillins, cephalosporins, and fluoroquinolones by Uropathogenic Escherichia coli (UPEC) has limited the options for selecting the appropriate antibiotic for the treatment of urinary tract infections.

  3. SIMULTANEOUS EFFECTS OF SHAKING AND TEMPERATURE ON VEROTOXIN1 PHAGE INDUCTION FROM VEROTOXIGENIC ESCHERICHIA COLI STRAINS

    Directory of Open Access Journals (Sweden)

    H. Hosain Zadegan, M. Sattari, M. H. Zahir, A. A. Allame

    2006-01-01

    Full Text Available Induction of lambda phage carring verotoxin1 gene from a verotoxigenic strains of Escherichia coli and released verotoxin1 were studied under environmental factors of shaking and termperature. Verotoxin1 phage in Escherichia coli PA 101 and transductants was confirmed by bacteriophage detection assay. Shaking of culture media and increasing temperature until 42 ºC increased phage particles in supernatants of Escherichia coli PA 101. Our results indicate that environmental factors such as shaking movements in natural inhabitates of bacteria such as river or sewage streams and temperature rise in summer season could be factors in induce and release free verotoxin1 – producing phage particles in nature that in turn could be the source of phage spreading to other related bacteria , and responsible for increased outbreaks of food borne diseases with verotoxigenic Escherichia coli in warm monthes of year in tropical areas.

  4. Shigella toxin inhibition of binding and translation of polyuridylic acid by Escherichia coli ribosomes.

    OpenAIRE

    Olenick, J G; Wolfe, A D

    1980-01-01

    Shigella toxin inhibits polyuridylic acid-directed polymerization of phenylalanine in ribosome-enzyme systems obtained from Escherichia coli or from Shigella dysenteriae. The inhibition is the result of toxin acting on ribosomes to prevent polyuridylic acid attachment.

  5. Differential decay of Enterococci and Escherichia coli originating from two fecal pollution sources

    Science.gov (United States)

    Using in situ subtropical aquatic mesocosms, fecal source (cattle manure versus sewage) was shown to be the most important contributor to differential loss in viability of fecal indicator bacteria (FIB), specifically enterococci in freshwater and Escherichia coli in marine habita...

  6. Selection of unique Escherichia coli clones by random amplified polymorphic DNA (RAPD)

    DEFF Research Database (Denmark)

    Nielsen, Karen L; Godfrey, Paul A; Stegger, Marc;

    2014-01-01

    Identifying and characterizing clonal diversity are important when analysing fecal flora. We evaluated random amplified polymorphic DNA (RAPD) PCR, applied for selection of Escherichia coli isolates, by whole genome sequencing. RAPD was fast, and reproducible as screening method for selection...

  7. Prevalence of Antibiotic Resistance in Escherichia coli Isolated from Poultry Meat Supply in Isfahan

    OpenAIRE

    Farhad Safarpordehkordi; Emad Yahaghi; Ebrahim Khodaverdi Darian

    2014-01-01

    Background and Aim: Unfortunately, conventional antibiotic therapies which were used for cases of food poisoning caused by Escherichia coli are costly and ineffective. This study was carried out in order to detection and investigates the antibiotic resistance pattern of Escherichia coli isolated from chicken meat distributed in Isfahan province. Materials and Methods: 220 chicken meat samples were collected from shopping centers in Isfahan province. Samples were initially cultured and geno...

  8. Isolation of Shiga toxin-producing Escherichia coli from raw milk in Kermanshah, Iran

    OpenAIRE

    Pantea Mohammadi; Ramin Abiri; Mansour Rezaei; Siavosh Salmanzadeh-Ahrabi

    2013-01-01

    Background and Objectives Infectious diarrhoeal diseases are great problem throughout the world and are responsible for considerable morbidity and mortality. Shiga toxin-producing Escherichia coli (STEC) is a major cause of gastroenteritis that may be complicated by hemorrhagic colitis (HC) or the hemolytic uremic syndrome (HUS), which is the main cause of acute renal failure in children. Food-borne outbreaks associated with Shiga toxin-producing Escherichia coli have been well documented wor...

  9. Genome Sequences of Two Copper-Resistant Escherichia coli Strains Isolated from Copper-Fed Pigs

    DEFF Research Database (Denmark)

    Lüthje, Freja L.; Hasman, Henrik; Aarestrup, Frank Møller; Alwathnani, Hend A.; Rensing, Christopher

    2014-01-01

    The draft genome sequences of two copper-resistant Escherichia coli strains were determined. These had been isolated from copper-fed pigs and contained additional putative operons conferring copper and other metal and metalloid resistances.......The draft genome sequences of two copper-resistant Escherichia coli strains were determined. These had been isolated from copper-fed pigs and contained additional putative operons conferring copper and other metal and metalloid resistances....

  10. Antibacterial activity of natural spices on multiple drug resistant Escherichia coli isolated from drinking water, Bangladesh

    OpenAIRE

    Rahman, Shahedur; Parvez, Anowar Khasru; Islam, Rezuanul; Khan, Mahboob Hossain

    2011-01-01

    Background Spices traditionally have been used as coloring agents, flavoring agents, preservatives, food additives and medicine in Bangladesh. The present work aimed to find out the antimicrobial activity of natural spices on multi-drug resistant Escherichia coli isolates. Methods Anti-bacterial potentials of six crude plant extracts (Allium sativum, Zingiber officinale, Allium cepa, Coriandrum sativum, Piper nigrum and Citrus aurantifolia) were tested against five Escherichia coli isolated f...

  11. Silver Nanoforms as a Therapeutic Agent for Killing Escherichia coli and Certain ESKAPE Pathogens.

    Science.gov (United States)

    Kedziora, A; Korzekwa, K; Strek, W; Pawlak, A; Doroszkiewicz, W; Bugla-Ploskonska, G

    2016-07-01

    The scope of this study included the preparation of silver nanoforms with high antimicrobial efficacy, low cost, and ease of application. The term 'silver nanoforms' refers to silver located on the amorphous or crystalline titanium dioxide (TiO2). Silver nanoforms may be used as an alternative to antibiotics in killing bacteria. Pure and silver-incorporated titanium (used as a carrier) was prepared using the sol-gel-modified method. Physical and chemical properties of the samples were described, and the antibacterial activity was indicated using the following strains of bacteria: Staphylococcus aureus, Klebsiella pneumoniae (ESKAPE pathogens), and Escherichia coli. The results have shown that the antibacterial activity of silver nanoforms with amorphous TiO2 is much better than that in the samples based on anatase (crystalline TiO2). The sensitivity of the tested bacteria to silver nanoforms depends on physical and chemical properties of the nanoforms and individual characteristics of the bacteria. For the first time, significant participation of amorphous TiO2 in antibacterial compounds has been described through this study. PMID:27086305

  12. Antimicrobial-resistant faecal Escherichia coli in wild mammals in central Europe: multiresistant Escherichia coli producing extended-spectrum ß-lactamases in wild boars

    DEFF Research Database (Denmark)

    Literak, I.; Dolejska, Monika; Radimersky, T.;

    2010-01-01

    Aims: To determine the presence of antibiotic-resistant faecal Escherichia coli in populations of wild mammals in the Czech Republic and Slovakia. Methods and Results: Rectal swabs or faeces collected during 2006-2008 from wild mammals were spread on MacConkey agar and MacConkey agar containing 2...... mg l-1 of cefotaxime. From plates with positive growth, one isolate was recovered and identified as E. coli. Susceptibility to 12 antibiotics was tested using the disk diffusion method. Resistance genes, class 1 and 2 integrons and gene cassettes were detected in resistant isolates by polymerase...... prevalence of resistant isolates was 2% in small terrestrial mammals (rodents and insectivores, n(E. coli) = 242), 12% in wild ruminants and foxes (n(E. coli) = 42), while no resistant isolates were detected in brown bears (n(E. coli) = 16). In wild boars (Sus scrofa) (n(E. coli) = 290), the prevalence of...

  13. Stimulation of Escherichia coli F-18Col- Type-1 fimbriae synthesis by leuX

    DEFF Research Database (Denmark)

    Newman, Joseph V.; Burghoff, Robert L.; Pallesen, Lars;

    1994-01-01

    Escherichia coli F-18, a normal human fecal isolate, is an excellent colonizer of the streptomycin-treated mouse large intestine. E. coli F-18Col-, a derivative of E. coli F-18 which no longer makes the E. coli F-18 colicin, colonizes the large intestine as well as E. coli F-18 when fed to mice...... alone but is eliminated when fed together with E. coli F-18. Recently we randomly cloned E. coli F-18 DNA into E. coli F-18Col- and let the mouse intestine select the best colonizer. In this way, we isolated a 6.5-kb E. coli F-18 DNA sequence that simultaneously stimulated synthesis of type 1 fimbriae...

  14. CRISPR Content Correlates with the Pathogenic Potential of Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Enriqueta García-Gutiérrez

    Full Text Available Guide RNA molecules (crRNA produced from clustered regularly interspaced short palindromic repeat (CRISPR arrays, altogether with effector proteins (Cas encoded by cognate cas (CRISPR associated genes, mount an interference mechanism (CRISPR-Cas that limits acquisition of foreign DNA in Bacteria and Archaea. The specificity of this action is provided by the repeat intervening spacer carried in the crRNA, which upon hybridization with complementary sequences enables their degradation by a Cas endonuclease. Moreover, CRISPR arrays are dynamic landscapes that may gain new spacers from infecting elements or lose them for example during genome replication. Thus, the spacer content of a strain determines the diversity of sequences that can be targeted by the corresponding CRISPR-Cas system reflecting its functionality. Most Escherichia coli strains possess either type I-E or I-F CRISPR-Cas systems. To evaluate their impact on the pathogenicity of the species, we inferred the pathotype and pathogenic potential of 126 strains of this and other closely related species and analyzed their repeat content. Our results revealed a negative correlation between the number of I-E CRISPR units in this system and the presence of pathogenicity traits: the median number of repeats was 2.5-fold higher for commensal isolates (with 29.5 units, range 0-53 than for pathogenic ones (12.0, range 0-42. Moreover, the higher the number of virulence factors within a strain, the lower the repeat content. Additionally, pathogenic strains of distinct ecological niches (i.e., intestinal or extraintestinal differ in repeat counts. Altogether, these findings support an evolutionary connection between CRISPR and pathogenicity in E. coli.

  15. A domain sequence approach to pangenomics: applications to Escherichia coli.

    Science.gov (United States)

    Snipen, Lars-Gustav; Ussery, David W

    2012-01-01

    The study of microbial pangenomes relies on the computation of gene families, i.e. the clustering of coding sequences into groups of essentially similar genes. There is no standard approach to obtain such gene families. Ideally, the gene family computations should be robust against errors in the annotation of genes in various genomes. In an attempt to achieve this robustness, we propose to cluster sequences by their domain sequence, i.e. the ordered sequence of domains in their protein sequence. In a study of 347 genomes from Escherichia coli we find on average around 4500 proteins having hits in Pfam-A in every genome, clustering into around 2500 distinct domain sequence families in each genome. Across all genomes we find a total of 5724 such families. A binomial mixture model approach indicates this is around 95% of all domain sequences we would expect to see in E. coli in the future. A Heaps law analysis indicates the population of domain sequences is larger, but this analysis is also very sensitive to smaller changes in the computation procedure. The resolution between strains is good despite the coarse grouping obtained by domain sequence families. Clustering sequences by their ordered domain content give us domain sequence families, who are robust to errors in the gene prediction step. The computational load of the procedure scales linearly with the number of genomes, which is needed for the future explosion in the number of re-sequenced strains. The use of domain sequence families for a functional classification of strains clearly has some potential to be explored. PMID:24555018

  16. Vanillin production by recombinant strains of Escherichia coli Produção de vanilina por linhagens recombinantes de Escherichia coli

    OpenAIRE

    Attilio Converti; Danilo de Faveri; Patrizia Perego; Paolo Barghini; Maurizio Ruzzi; Luciane Sene

    2003-01-01

    Vanillin production from ferulate was studied using different recombinant strains of Escherichia coli. To prevent the occurrence of aerobic conditions and then possible product oxidation, tests were performed in Erlenmeyer flasks under mild mixing (150 rpm). Among other transformants, E. coli JM109(pBB1) appeared to be the best vanillin producer, being able to convert no less than 95% of starting ferulate to the product within 1h. This yield decreased down to 72% after 72h, likely because of ...

  17. Prevalence and geographical distribution of Escherichia coli O157 in India: a 10-year survey.

    Science.gov (United States)

    Sehgal, Rakesh; Kumar, Yashwant; Kumar, Sunil

    2008-04-01

    Escherichia coli colonizes the human gastrointestinal tract and produces a variety of diseases. Escherichia coli O157 is one of the most important pathogenic strains reported from food-borne illnesses leading to enterohemorrhagic colitis. The National Salmonella and Escherichia Centre is a national reference centre for Salmonella and Escherichia for India; it receives samples from research laboratories, hospitals and institutions for serological identification. The present study is an epidemiological survey of E. coli O157 in different regions of India. The data are based on samples received from humans, food items, animals and the environment. A total of 17 093 isolates cultured from samples were received during the 10-year period of which 5678 were from human sources. Thirty (0.5%) human samples were positive for E. coli O157. A significantly high percentage of E. coli O157 were isolated from meat (0.9%, 13/1376), milk and milk products (1.8%, 10/553), seafood (8.4%, 16/190) and water (1.6%, 8/486). The isolates were found to be distributed among domestic and wild animals, and the maximum number of isolates of E. coli O157 was detected in samples received from coastal belt areas. Escherichia coli O157 is widely distributed among humans and animals, food and environment in different geographical regions of India. PMID:18321544

  18. Molecular Cloning of Genes for Cellobiose Utilization and Their Expression in Escherichia coli

    OpenAIRE

    Armentrout, Richard W.; Brown, Ronald D.

    1981-01-01

    The genes for cellobiose utilization in Escherichia adecarboxylata were cloned by using recombinant deoxyribonucleic acid techniques and transferred to Escherichia coli. Preliminary analysis of the β-glucosidase activity expressed in these host cells indicated that the enzyme is membrane bound and required magnesium ions, phosphate ions, and heat-stable, non-dialyzable factors from the bacterial cytoplasm.

  19. Functional genomics by NMR spectroscopy. Phenylacetate catabolism in Escherichia coli.

    Science.gov (United States)

    Ismail, Wael; El-Said Mohamed, Magdy; Wanner, Barry L; Datsenko, Kirill A; Eisenreich, Wolfgang; Rohdich, Felix; Bacher, Adelbert; Fuchs, Georg

    2003-07-01

    Aerobic metabolism of phenylalanine in most bacteria proceeds via oxidation to phenylacetate. Surprisingly, the further metabolism of phenylacetate has not been elucidated, even in well studied bacteria such as Escherichia coli. The only committed step is the conversion of phenylacetate into phenylacetyl-CoA. The paa operon of E. coli encodes 14 polypeptides involved in the catabolism of phenylacetate. We have found that E. coli K12 mutants with a deletion of the paaF, paaG, paaH, paaJ or paaZ gene are unable to grow with phenylacetate as carbon source. Incubation of a paaG mutant with [U-13C8]phenylacetate yielded ring-1,2-dihydroxy-1,2-dihydrophenylacetyl lactone as shown by NMR spectroscopy. Incubation of the paaF and paaH mutants with phenylacetate yielded delta3-dehydroadipate and 3-hydroxyadipate, respectively. The origin of the carbon atoms of these C6 compounds from the aromatic ring was shown using [ring-13C6]phenylacetate. The paaG and paaZ mutants also converted phenylacetate into ortho-hydroxyphenylacetate, which was previously identified as a dead end product of phenylacetate catabolism. These data, in conjunction with protein sequence data, suggest a novel catabolic pathway via CoA thioesters. According to this, phenylacetyl-CoA is attacked by a ring-oxygenase/reductase (PaaABCDE proteins), generating a hydroxylated and reduced derivative of phenylacetyl-CoA, which is not re-oxidized to a dihydroxylated aromatic intermediate, as in other known aromatic pathways. Rather, it is proposed that this nonaromatic intermediate CoA ester is further metabolized in a complex reaction sequence comprising enoyl-CoA isomerization/hydration, nonoxygenolytic ring opening, and dehydrogenation catalyzed by the PaaG and PaaZ proteins. The subsequent beta-oxidation-type degradation of the resulting CoA dicarboxylate via beta-ketoadipyl-CoA to succinyl-CoA and acetyl-CoA appears to be catalyzed by the PaaJ, PaaF and PaaH proteins. PMID:12846838

  20. Overexpression of Peanut Diacylglycerol Acyltransferase 2 in Escherichia coli

    Science.gov (United States)

    Yang, Lianqun; Zhang, Bin; Chen, Gao; Bi, Yuping

    2013-01-01

    Diacylglycerol acyltransferase (DGAT) is the rate-limiting enzyme in triacylglycerol biosynthesis in eukaryotic organisms. Triacylglycerols are important energy-storage oils in plants such as peanuts, soybeans and rape. In this study, Arachis hypogaea type 2 DGAT (AhDGAT2) genes were cloned from the peanut cultivar ‘Luhua 14’ using a homologous gene sequence method and rapid amplification of cDNA ends. To understand the role of AhDGAT2 in triacylglycerol biosynthesis, two AhDGAT2 nucleotide sequences that differed by three amino acids were expressed as glutathione S-transferase (GST) fusion proteins in Escherichia coli Rosetta (DE3). Following IPTG induction, the isozymes (AhDGAT2a and AhDGAT2b) were expressed as 64.5 kDa GST fusion proteins. Both AhDGAT2a and AhDGAT2b occurred in the host cell cytoplasm and inclusion bodies, with larger amounts in the inclusion bodies. Overexpression of AhDGATs depressed the host cell growth rates relative to non-transformed cells, but cells harboring empty-vector, AhDGAT2a–GST, or AhDGAT2b–GST exhibited no obvious growth rate differences. Interestingly, induction of AhDGAT2a–GST and AhDGAT2b–GST proteins increased the sizes of the host cells by 2.4–2.5 times that of the controls (post-IPTG induction). The total fatty acid (FA) levels of the AhDGAT2a–GST and AhDGAT2a–GST transformants, as well as levels of C12:0, C14:0, C16:0, C16:1, C18:1n9c and C18:3n3 FAs, increased markedly, whereas C15:0 and C21:0 levels were lower than in non-transformed cells or those containing empty-vectors. In addition, the levels of some FAs differed between the two transformant strains, indicating that the two isozymes might have different functions in peanuts. This is the first time that a full-length recombinant peanut DGAT2 has been produced in a bacterial expression system and the first analysis of its effects on the content and composition of fatty acids in E. coli. Our results indicate that AhDGAT2 is a strong candidate gene for

  1. Overexpression of peanut diacylglycerol acyltransferase 2 in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Zhenying Peng

    Full Text Available Diacylglycerol acyltransferase (DGAT is the rate-limiting enzyme in triacylglycerol biosynthesis in eukaryotic organisms. Triacylglycerols are important energy-storage oils in plants such as peanuts, soybeans and rape. In this study, Arachis hypogaea type 2 DGAT (AhDGAT2 genes were cloned from the peanut cultivar 'Luhua 14' using a homologous gene sequence method and rapid amplification of cDNA ends. To understand the role of AhDGAT2 in triacylglycerol biosynthesis, two AhDGAT2 nucleotide sequences that differed by three amino acids were expressed as glutathione S-transferase (GST fusion proteins in Escherichia coli Rosetta (DE3. Following IPTG induction, the isozymes (AhDGAT2a and AhDGAT2b were expressed as 64.5 kDa GST fusion proteins. Both AhDGAT2a and AhDGAT2b occurred in the host cell cytoplasm and inclusion bodies, with larger amounts in the inclusion bodies. Overexpression of AhDGATs depressed the host cell growth rates relative to non-transformed cells, but cells harboring empty-vector, AhDGAT2a-GST, or AhDGAT2b-GST exhibited no obvious growth rate differences. Interestingly, induction of AhDGAT2a-GST and AhDGAT2b-GST proteins increased the sizes of the host cells by 2.4-2.5 times that of the controls (post-IPTG induction. The total fatty acid (FA levels of the AhDGAT2a-GST and AhDGAT2a-GST transformants, as well as levels of C12:0, C14:0, C16:0, C16:1, C18:1n9c and C18:3n3 FAs, increased markedly, whereas C15:0 and C21:0 levels were lower than in non-transformed cells or those containing empty-vectors. In addition, the levels of some FAs differed between the two transformant strains, indicating that the two isozymes might have different functions in peanuts. This is the first time that a full-length recombinant peanut DGAT2 has been produced in a bacterial expression system and the first analysis of its effects on the content and composition of fatty acids in E. coli. Our results indicate that AhDGAT2 is a strong candidate gene for

  2. Production of extracellular fatty acid using engineered Escherichia coli

    Directory of Open Access Journals (Sweden)

    Liu Hui

    2012-04-01

    Full Text Available Abstract Background As an alternative for economic biodiesel production, the microbial production of extracellular fatty acid from renewable resources is receiving more concerns recently, since the separation of fatty acid from microorganism cells is normally involved in a series of energy-intensive steps. Many attempts have been made to construct fatty acid producing strains by targeting genes in the fatty acid biosynthetic pathway, while few studies focused on the cultivation process and the mass transfer kinetics. Results In this study, both strain improvements and cultivation process strategies were applied to increase extracellular fatty acid production by engineered Escherichia coli. Our results showed overexpressing ‘TesA and the deletion of fadL in E. coli BL21 (DE3 improved extracellular fatty acid production, while deletion of fadD didn’t strengthen the extracellular fatty acid production for an undetermined mechanism. Moreover, the cultivation process controls contributed greatly to extracellular fatty acid production with respect to titer, cell growth and productivity by adjusting the temperature, adding ampicillin and employing on-line extraction. Under optimal conditions, the E. coli strain (pACY-‘tesA-ΔfadL produced 4.8 g L−1 extracellular fatty acid, with the specific productivity of 0.02 g h−1 g−1dry cell mass, and the yield of 4.4% on glucose, while the ratios of cell-associated fatty acid versus extracellular fatty acid were kept below 0.5 after 15 h of cultivation. The fatty acids included C12:1, C12:0, C14:1, C14:0, C16:1, C16:0, C18:1, C18:0. The composition was dominated by C14 and C16 saturated and unsaturated fatty acids. Using the strain pACY-‘tesA, similar results appeared under the same culture conditions and the titer was also much higher than that ever reported previously, which suggested that the supposedly superior strain did not necessarily perform best for the efficient production of desired

  3. Protein abundance profiling of the Escherichia coli cytosol

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    Mann Matthias

    2008-02-01

    Full Text Available Abstract Background Knowledge about the abundance of molecular components is an important prerequisite for building quantitative predictive models of cellular behavior. Proteins are central components of these models, since they carry out most of the fundamental processes in the cell. Thus far, protein concentrations have been difficult to measure on a large scale, but proteomic technologies have now advanced to a stage where this information becomes readily accessible. Results Here, we describe an experimental scheme to maximize the coverage of proteins identified by mass spectrometry of a complex biological sample. Using a combination of LC-MS/MS approaches with protein and peptide fractionation steps we identified 1103 proteins from the cytosolic fraction of the Escherichia coli strain MC4100. A measure of abundance is presented for each of the identified proteins, based on the recently developed emPAI approach which takes into account the number of sequenced peptides per protein. The values of abundance are within a broad range and accurately reflect independently measured copy numbers per cell. As expected, the most abundant proteins were those involved in protein synthesis, most notably ribosomal proteins. Proteins involved in energy metabolism as well as those with binding function were also found in high copy number while proteins annotated with the terms metabolism, transcription, transport, and cellular organization were rare. The barrel-sandwich fold was found to be the structural fold with the highest abundance. Highly abundant proteins are predicted to be less prone to aggregation based on their length, pI values, and occurrence patterns of hydrophobic stretches. We also find that abundant proteins tend to be predominantly essential. Additionally we observe a significant correlation between protein and mRNA abundance in E. coli cells. Conclusion Abundance measurements for more than 1000 E. coli proteins presented in this work

  4. Clonal relationships among bloodstream isolates of Escherichia coli.

    Science.gov (United States)

    Maslow, J N; Whittam, T S; Gilks, C F; Wilson, R A; Mulligan, M E; Adams, K S; Arbeit, R D

    1995-01-01

    The clonal relationships among 187 bloodstream isolates of Escherichia coli from 179 patients at Boston, Mass., Long Beach, Calif., and Nairobi, Kenya, were determined by multilocus enzyme electrophoresis (MLEE), analysis of polymorphisms associated with the ribosomal operon (ribotyping), and serotyping. MLEE based on 20 enzymes resolved 101 electrophoretic types (ETs), forming five clusters; ribotyping resolved 56 distinct patterns concordant with the analysis by MLEE. The isolates at each study site formed a genetically diverse group and demonstrated similar clonal structures, with the same small subset of lineages accounting for the majority of isolates at each site. Moreover, two ribotypes accounted for approximately 30% of the isolates at each study site. One cluster contained the majority (65%) of isolates and, by direct comparison of the ETs and ribotypes of individual isolates, was genetically indistinguishable from the largest cluster for each of two other collections of E. coli causing pyelonephritis and neonatal meningitis (R. K. Selander, T. K. Korhonen, V. Väisänen-Rhen, P. H. Williams, P. E. Pattison, and D. A. Caugent, Infect. Immun. 52:213-222, 1986; M. Arthur, C. E. Johnson, R. H. Rubin, R. D. Arbeit, C. Campanelli, C. Kim, S. Steinbach, M. Agarwal, R. Wilkinson, and R. Goldstein, Infect. Immun. 57:303-313, 1989), thus defining a virulent set of lineages. The isolates within these virulent lineages typically carried DNA homologous to the adhesin operon pap or sfa and the hemolysin operon hly and expressed O1, O2, O4, O6, O18, O25, or O75 antigens. DNA homologous to pap was distributed among isolates of each major cluster, whereas hly was restricted to isolates of two clusters, typically detected in pap-positive strains, and sfa was restricted to isolates of one cluster, typically detected in pap- and hly-positive strains. The occurrence of pap-positive isolates in the same geographically and genetically divergent lineages suggests that this

  5. Inducible Escherichia coli fermentation for increased plasmid DNA production.

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    Carnes, Aaron E; Hodgson, Clague P; Williams, James A

    2006-11-01

    Bacterial plasmids are the vectors of choice for DNA vaccines and short-term gene therapeutics. Growing plasmid DNA by microbial (Escherichia coli) fermentation is usually combined with alkaline lysis/chromatography methods of purification. To date, typical plasmid fermentation media and processes result in yields of 100-250 mg of plasmid DNA/l of culture medium, using standard high-copy pUC origin-containing plasmids. In order to address this initial and yield-limiting upstream step, we identified novel fermentation control parameters for fed-batch fermentation. The resulting fermentation strategies significantly increased specific plasmid yield with respect to cell mass while enhancing plasmid integrity and maintaining supercoiled DNA content. Fed-batch fermentation yield exceeding 1000 mg of plasmid DNA/l was obtained after reduction of plasmid-mediated metabolic burden during growth, and yields up to 1500 mg of plasmid DNA/l have been achieved with optimized plasmid backbones. Interestingly, by inducing high plasmid levels after sufficient biomass accumulation at low temperature and restricted growth, cells were able to tolerate significantly higher plasmid quantities than cells grown by conventional processes. This 5-10-fold increase in plasmid yield dramatically decreases plasmid manufacturing costs and improves the effectiveness of downstream purification by reducing the fraction of impurities. PMID:16819941

  6. Ferritinophagy drives uropathogenic Escherichia coli persistence in bladder epithelial cells.

    Science.gov (United States)

    Bauckman, Kyle A; Mysorekar, Indira U

    2016-05-01

    Autophagy is a cellular recycling pathway, which in many cases, protects host cells from infections by degrading pathogens. However, uropathogenic Escherichia coli (UPEC), the predominant cause of urinary tract infections (UTIs), persist within the urinary tract epithelium (urothelium) by forming reservoirs within autophagosomes. Iron is a critical nutrient for both host and pathogen, and regulation of iron availability is a key host defense against pathogens. Iron homeostasis depends on the shuttling of iron-bound ferritin to the lysosome for recycling, a process termed ferritinophagy (a form of selective autophagy). Here, we demonstrate for the first time that UPEC shuttles with ferritin-bound iron into the autophagosomal and lysosomal compartments within the urothelium. Iron overload in urothelial cells induces ferritinophagy in an NCOA4-dependent manner causing increased iron availability for UPEC, triggering bacterial overproliferation and host cell death. Addition of even moderate levels of iron is sufficient to increase and prolong bacterial burden. Furthermore, we show that lysosomal damage due to iron overload is the specific mechanism causing host cell death. Significantly, we demonstrate that host cell death and bacterial burden can be reversed by inhibition of autophagy or inhibition of iron-regulatory proteins, or chelation of iron. Together, our findings suggest that UPEC persist in host cells by taking advantage of ferritinophagy. Thus, modulation of iron levels in the bladder may provide a therapeutic avenue to controlling UPEC persistence, epithelial cell death, and recurrent UTIs. PMID:27002654

  7. Cadmium biosorption by polyvinyl alcohol immobilized recombinant Escherichia coli

    International Nuclear Information System (INIS)

    Recombinant Escherichia coli expressing human metallothionein protein was immobilized with polyvinyl alcohol (PVA) for the removal of cadmium from solution. The adsorption ability was strongly affected by pH with optimal performance at pH 5.0, while it was less sensitive to temperature over the range of 20-42 deg. C. The adsorption kinetics and equilibrium of PVA-immobilized cells was best described by pseudo-second order model and Langmuir isotherm, respectively. Over the Cd concentrations range of 10-150 mg/l, PVA-cells had the highest Cd removal percentage (82.7%) at 10 mg Cd/l and a biomass loading of 15.4 wt.%. Better adsorption ability was obtained when biomass loading was increased, as the highest adsorption capacity of 4.29 mg/g was achieved at 33.0 wt.% of biomass (initial Cd concentration = 100 mg/l). An aqueous solution of 0.01 M Na3NTA displayed the best desorption efficiency (57-89%) for four A/D cycles, while 51-61% of the original adsorption capacity was retained after regeneration.

  8. Recombination Phenotypes of Escherichia coli greA Mutants

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    Poteete Anthony R

    2011-03-01

    Full Text Available Abstract Background The elongation factor GreA binds to RNA polymerase and modulates transcriptional pausing. Some recent research suggests that the primary role of GreA may not be to regulate gene expression, but rather, to promote the progression of replication forks which collide with RNA polymerase, and which might otherwise collapse. Replication fork collapse is known to generate dsDNA breaks, which can be recombinogenic. It follows that GreA malfunction could have consequences affecting homologous recombination. Results Escherichia coli mutants bearing substitutions of the active site acidic residues of the transcription elongation factor GreA, D41N and E44K, were isolated as suppressors of growth inhibition by a toxic variant of the bacteriophage lambda Red-beta recombination protein. These mutants, as well as a D41A greA mutant and a greA deletion, were tested for proficiency in recombination events. The mutations were found to increase the efficiency of RecA-RecBCD-mediated and RecA-Red-mediated recombination, which are replication-independent, and to decrease the efficiency of replication-dependent Red-mediated recombination. Conclusion These observations provide new evidence for a role of GreA in resolving conflicts between replication and transcription.

  9. An Integrated System for Precise Genome Modification in Escherichia coli.

    Science.gov (United States)

    Tas, Huseyin; Nguyen, Cac T; Patel, Ravish; Kim, Neil H; Kuhlman, Thomas E

    2015-01-01

    We describe an optimized system for the easy, effective, and precise modification of the Escherichia coli genome. Genome changes are introduced first through the integration of a 1.3 kbp Landing Pad consisting of a gene conferring resistance to tetracycline (tetA) or the ability to metabolize the sugar galactose (galK). The Landing Pad is then excised as a result of double-strand breaks by the homing endonuclease I-SceI, and replaced with DNA fragments bearing the desired change via λ-Red mediated homologous recombination. Repair of the double strand breaks and counterselection against the Landing Pad (using NiCl2 for tetA or 2-deoxy-galactose for galK) allows the isolation of modified bacteria without the use of additional antibiotic selection. We demonstrate the power of this method to make a variety of genome modifications: the exact integration, without any extraneous sequence, of the lac operon (~6.5 kbp) to any desired location in the genome and without the integration of antibiotic markers; the scarless deletion of ribosomal rrn operons (~6 kbp) through either intrachromosomal or oligonucleotide recombination; and the in situ fusion of native genes to fluorescent reporter genes without additional perturbation. PMID:26332675

  10. An Integrated System for Precise Genome Modification in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Huseyin Tas

    Full Text Available We describe an optimized system for the easy, effective, and precise modification of the Escherichia coli genome. Genome changes are introduced first through the integration of a 1.3 kbp Landing Pad consisting of a gene conferring resistance to tetracycline (tetA or the ability to metabolize the sugar galactose (galK. The Landing Pad is then excised as a result of double-strand breaks by the homing endonuclease I-SceI, and replaced with DNA fragments bearing the desired change via λ-Red mediated homologous recombination. Repair of the double strand breaks and counterselection against the Landing Pad (using NiCl2 for tetA or 2-deoxy-galactose for galK allows the isolation of modified bacteria without the use of additional antibiotic selection. We demonstrate the power of this method to make a variety of genome modifications: the exact integration, without any extraneous sequence, of the lac operon (~6.5 kbp to any desired location in the genome and without the integration of antibiotic markers; the scarless deletion of ribosomal rrn operons (~6 kbp through either intrachromosomal or oligonucleotide recombination; and the in situ fusion of native genes to fluorescent reporter genes without additional perturbation.

  11. Characterization of RNA damage under oxidative stress in Escherichia coli

    Science.gov (United States)

    Liu, Min; Gong, Xin; Alluri, Ravi Kumar; Wu, Jinhua; Sablo, Tene’; Li, Zhongwei

    2012-01-01

    We have examined the level of 8-hydroxyguanosine (8-oxo-G), an oxidized form of guanosine, in RNA in Escherichia coli under normal and oxidative stress conditions. The level of 8-oxo-G in RNA rises rapidly and remains high for hours in response to hydrogen peroxide (H2O2) challenge in a dose-dependent manner. H2O2 induced elevation of 8-oxo-G content is much higher in RNA than that of 8-hydroxydeoxyguanosine (8-oxo-dG) in DNA. Under normal conditions, the 8-oxo-G level is low in RNA isolated from the ribosome and it is nearly three times higher in non-ribosomal RNAs. In contrast, 8-oxo-G generated by a short exposure to H2O2 is almost equally distributed in various RNA species, suggesting that although ribosomal RNAs are normally less oxidized, they are not protected against exogenous H2O2. Interestingly, highly folded RNA is not protected from oxidation because 8-oxo-G generated by H2O2 treatment in vitro increases to approximately the same levels in tRNA and rRNA in both native and denatured forms. Lastly, increased RNA oxidation is closely associated with cell death by oxidative stress. Our data suggests that RNA is a primary target for reactive oxygen species and RNA oxidation is part of the paradox that cells have to deal with under oxidative stress. PMID:22718628

  12. Polynucleotide Phosphorylase Protects Escherichia coli against Oxidative Stress†

    Science.gov (United States)

    Wu, Jinhua; Jiang, Zhe; Liu, Min; Gong, Xin; Wu, Shaohui; Burns, Christopher M.; Li, Zhongwei

    2009-01-01

    Escherichia coli polynucleotide phosphorylase (PNPase) primarily functions in RNA degradation. It is an exoribonuclease and integral component of the multienzyme RNA degradosome complex [Carpousis et al. (1994) Cell 76, 889]. PNPase was previously shown to specifically bind a synthetic RNA containing the oxidative lesion 8-hydroxyguanine (8-oxoG) [Hayakawa et al. (2001) Biochemistry 40, 9977], suggesting a possible role in removing oxidatively damaged RNA. Here we show that PNPase binds to RNA molecules of natural sequence that were oxidatively damaged by treatment with hydrogen peroxide (H2O2) postsynthetically. PNPase bound oxidized RNA with higher affinity than untreated RNA of the same sequence, raising the possibility that it may act against a wide variety of lesions. The importance of such a protective role is illustrated by the observation that, under conditions known to cause oxidative damage to cytoplasmic components, PNPase-deficient cells are less viable than wild-type cells. Further, when challenged with H2O2, PNPase-deficient cells accumulate 8-oxoG in cellular RNA to a greater extent than wild-type cells, suggesting that this RNase functions in minimizing oxidized RNA in vivo. Introducing the pnp gene encoding PNPase rescues defects in growth and RNA quality of the pnp mutant cells. Our results also suggest that protection against oxidative stress is an intrinsic function of PNPase because association with the RNA degradosome or with RNA helicase B (RhlB) is not required. PMID:19219992

  13. Penicillin-binding site on the Escherichia coli cell envelope

    International Nuclear Information System (INIS)

    The binding of 35S-labeled penicillin to distinct penicillin-binding proteins (PBPs) of the cell envelope obtained from the sonication of Escherichia coli was studied at different pHs ranging from 4 to 11. Experiments distinguishing the effect of pH on penicillin binding by PBP 5/6 from its effect on beta-lactamase activity indicated that although substantial binding occurred at the lowest pH, the amount of binding increased with pH, reaching a maximum at pH 10. Based on earlier studies, it is proposed that the binding at high pH involves the formation of a covalent bond between the C-7 of penicillin and free epsilon amino groups of the PBPs. At pHs ranging from 4 to 8, position 1 of penicillin, occupied by sulfur, is considered to be the site that establishes a covalent bond with the sulfhydryl groups of PBP 5. The use of specific blockers of free epsilon amino groups or sulfhydryl groups indicated that wherever the presence of each had little or no effect on the binding of penicillin by PBP 5, the presence of both completely prevented binding. The specific blocker of the hydroxyl group of serine did not affect the binding of penicillin

  14. Expression of Plasmodium falciparum lactate dehydrogenase in Escherichia coli.

    Science.gov (United States)

    Bzik, D J; Fox, B A; Gonyer, K

    1993-05-01

    A Plasmodium falciparum gene is described which encodes lactate dehydrogenase activity (P. falciparum LDH). The P. falciparum LDH gene contains no introns and is present in a single copy on chromosome 13. P. falciparum LDH was expressed in all asexual blood stages as a 1.6-kb mRNA. The predicted 316 amino acid protein coding region of P. falciparum LDH was inserted into the prokaryotic expression vector pKK223-3 and a 33-kDa protein having LDH activity was synthesized in Escherichia coli. P. falciparum LDH primary structure displays high amino acid similarity (50-57%) to vertebrate and bacterial LDH, but lacks the amino terminal extension observed in all vertebrate LDH. The majority of amino acid residues implicated in substrate and coenzyme binding and catalysis of other LDH are well conserved in P. falciparum LDH. However, several notable differences in amino acid composition were observed. P. falciparum LDH contained several distinctive single amino acid insertions and deletions compared to other LDH enzymes, and most remarkably, it contained a novel insertion of 5 amino acids within the conserved mobile loop region near arginine residue 109, a residue which is known to make contact with pyruvate in the ternary complex of other LDH. These results suggest that novel features of P. falciparum LDH primary structure may be correlated with previously characterized and distinctive kinetic, biochemical, immunochemical, and electrophoretic properties of P. falciparum LDH. PMID:8515777

  15. Expression of fully functional tetrameric human hemoglobin in Escherichia coli

    International Nuclear Information System (INIS)

    Synthesis genes encoding the human α- and β-globin polypeptides have been expressed from a single operon in Escherichia coli. The α- and β-globin polypeptides associate into soluble tetramers, incorporate heme, and accumulate to >5% of the total cellular protein. Purified recombinant hemoglobin has the correct stoichiometry of α- and β-globin chains and contains a full complement of heme. Each globin chain also contains an additional methionine as an extension to the amino terminus. The recombinant hemoglobin has a C4 reversed-phase HPLC profile essentially identical to that of human hemoglobin A0 and comigrates with hemoglobin A0 on SDS/PAGE. The visible spectrum and oxygen affinity are similar to that of native human hemoglobin A0. The authors have also expressed the α- and β-globin genes separately and found that the expression of the α-globin gene alone results in a marked decrease in the accumulation of α-globin in the cell. Separate expression of the β-globin gene results in high levels of insoluble β-globin. These observations suggest that the presence of α- and β-globin in the same cell stabilizes α-globin and aids the correct folding of β-globin. This system provides a simple method for expressing large quantities of recombinant hemoglobin and allows facile manipulation of the genes encoding hemoglobin to produce functionally altered forms of this protein

  16. Escherichia coli modulates its motor speed on sensing an attractant.

    Science.gov (United States)

    Karmakar, Richa; Naaz, Farha; Tirumkudulu, Mahesh S; Venkatesh, K V

    2016-10-01

    It is well known that Escherichia coli achieves chemotaxis by modulating the bias of the flagellar motor. Recent experiments have shown that the bacteria vary their swimming speeds as well in presence of attractants. However, this increase in the swimming speed in response to the attractants has not been correlated with the increase in the flagellar motor speed. Using flickering dark-field microscopy, we measure the head-rotation speed of a large population of cells to correlate it with the flagellar motor speed. Experiments performed with wild-type and trg-deletion mutant strains suggest that the cells are capable of modulating the flagellar motor speed via mere sensing of a ligand. The motor speed can be further correlated with the swimming speed of the cells and was found to be linear. These results suggest the existence of a hitherto unknown intra-cellular pathway that modulates the flagellar motor speed in response to sensing of chemicals, thereby making chemotaxis more efficient than previously known. PMID:27318664

  17. Mutagenic DNA repair in Escherichia coli: Pt. 18

    International Nuclear Information System (INIS)

    UV light was unable to induce rifampicin-resistant mutations at 430C in Escherichia coli ER11 and dnaE486. Although DnaE486 gene product is inactive at 430C, these bacteria contain the pcbA1 mutation which allows DNA replication provided DNA polymerase I is functional. The experiments were carried out under conditions where full expression of rifampicin-resistant mutations could occur so that the lack of induced mutations cannot be ascribed to an effect of incubation at 430C on mutation expression. UV-mutability at 43(0)C was restored by the presence of the dnaE+ allele on a plasmid. It is concluded that functional DnaE protein is essential for UV mutagenesis. The dnaE486 mutation also blocked the induction at 430C of mutations induced by UV plus delayed photoreversal, a procedure that has been postulated to reflect an early misincorporation step in the UV mutagenic process. (Author)

  18. Signal integration in the galactose network of Escherichia coli.

    Science.gov (United States)

    Semsey, Szabolcs; Krishna, Sandeep; Sneppen, Kim; Adhya, Sankar

    2007-07-01

    The gal regulon of Escherichia coli contains genes involved in galactose transport and metabolism. Transcription of the gal regulon genes is regulated in different ways by two iso-regulatory proteins, Gal repressor (GalR) and Gal isorepressor (GalS), which recognize the same binding sites in the absence of d-galactose. DNA binding by both GalR and GalS is inhibited in the presence of d-galactose. Many of the gal regulon genes are activated in the presence of the adenosine cyclic-3',5'-monophosphate (cAMP)-cAMP receptor protein (CRP) complex. We studied transcriptional regulation of the gal regulon promoters simultaneously in a purified system and attempted to integrate the two small molecule signals, d-galactose and cAMP, that modulate the isoregulators and CRP respectively, at each promoter, using Boolean logic. Results show that similarly organized promoters can have different input functions. We also found that in some cases the activity of the promoter and the cognate gene can be described by different logic gates. We combined the transcriptional network of the galactose regulon, obtained from our experiments, with literature data to construct an integrated map of the galactose network. Structural analysis of the network shows that at the interface of the genetic and metabolic network, feedback loops are by far the most common motif. PMID:17630975

  19. Photoluminescent gold nanoclusters as sensing probes for uropathogenic Escherichia coli.

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    Po-Han Chan

    Full Text Available Glycan-bound nanoprobes have been demonstrated as suitable sensing probes for bacteria containing glycan binding sites. In this study, we demonstrated a facile approach for generating glycan-bound gold nanoclusters (AuNCs. The generated AuNCs were used as sensing probes for corresponding target bacteria. Mannose-capped AuNCs (AuNCs@Mann were generated and used as the model sensors for target bacteria. A one-step synthesis approach was employed to generate AuNCs@Mann. In this approach, an aqueous solution of tetrachloroauric acid and mannoside that functionized with a thiol group (Mann-SH was stirred at room temperature for 48 h. The mannoside functions as reducing and capping agent. The size of the generated AuNCs@Mann is 1.95±0.27 nm, whereas the AuNCs with red photoluminescence have a maximum emission wavelength of ~630 nm (λexcitation = 375 nm. The synthesis of the AuNCs@Mann was accelerated by microwave heating, which enabled the synthesis of the AuNCs@Mann to complete within 1 h. The generated AuNCs@Mann are capable of selectively binding to the urinary tract infection isolate Escherichia coli J96 containing the mannose binding protein FimH expressed on the type 1 pili. On the basis of the naked eye observation, the limit of detection of the sensing approach is as low as ~2×10(6 cells/mL.

  20. Chemotactic response and adaptation dynamics in Escherichia coli.

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    Diana Clausznitzer

    2010-05-01

    Full Text Available Adaptation of the chemotaxis sensory pathway of the bacterium Escherichia coli is integral for detecting chemicals over a wide range of background concentrations, ultimately allowing cells to swim towards sources of attractant and away from repellents. Its biochemical mechanism based on methylation and demethylation of chemoreceptors has long been known. Despite the importance of adaptation for cell memory and behavior, the dynamics of adaptation are difficult to reconcile with current models of precise adaptation. Here, we follow time courses of signaling in response to concentration step changes of attractant using in vivo fluorescence resonance energy transfer measurements. Specifically, we use a condensed representation of adaptation time courses for efficient evaluation of different adaptation models. To quantitatively explain the data, we finally develop a dynamic model for signaling and adaptation based on the attractant flow in the experiment, signaling by cooperative receptor complexes, and multiple layers of feedback regulation for adaptation. We experimentally confirm the predicted effects of changing the enzyme-expression level and bypassing the negative feedback for demethylation. Our data analysis suggests significant imprecision in adaptation for large additions. Furthermore, our model predicts highly regulated, ultrafast adaptation in response to removal of attractant, which may be useful for fast reorientation of the cell and noise reduction in adaptation.

  1. Non-genetic individuality in Escherichia coli motor switching

    International Nuclear Information System (INIS)

    By analyzing 30 min, high-resolution recordings of single Escherichia coli flagellar motors in the physiological regime, we show that two main properties of motor switching—the mean clockwise and mean counter-clockwise interval durations—vary significantly. When we represent these quantities on a two-dimensional plot for several cells, the data do not fall on a one-dimensional curve, as expected with a single control parameter, but instead spread in two dimensions, pointing to motor individuality. The largest variations are in the mean counter-clockwise interval, and are attributable to variations in the concentration of the internal signaling molecule CheY-P. In contrast, variations in the mean clockwise interval are interpreted in terms of motor individuality. We argue that the sensitivity of the mean counter-clockwise interval to fluctuations in CheY-P is consistent with an optimal strategy of run and tumble. The concomittent variability in mean run length may allow populations of cells to better survive in rapidly changing environments by 'hedging their bets'. (communication)

  2. Oxidative Stress in Shiga Toxin Production by Enterohemorrhagic Escherichia coli

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    Katarzyna Licznerska

    2016-01-01

    Full Text Available Virulence of enterohemorrhagic Escherichia coli (EHEC strains depends on production of Shiga toxins. These toxins are encoded in genomes of lambdoid bacteriophages (Shiga toxin-converting phages, present in EHEC cells as prophages. The genes coding for Shiga toxins are silent in lysogenic bacteria, and prophage induction is necessary for their efficient expression and toxin production. Under laboratory conditions, treatment with UV light or antibiotics interfering with DNA replication are commonly used to induce lambdoid prophages. Since such conditions are unlikely to occur in human intestine, various research groups searched for other factors or agents that might induce Shiga toxin-converting prophages. Among other conditions, it was reported that treatment with H2O2 caused induction of these prophages, though with efficiency significantly lower relative to UV-irradiation or mitomycin C treatment. A molecular mechanism of this phenomenon has been proposed. It appears that the oxidative stress represents natural conditions provoking induction of Shiga toxin-converting prophages as a consequence of H2O2 excretion by either neutrophils in infected humans or protist predators outside human body. Finally, the recently proposed biological role of Shiga toxin production is described in this paper, and the “bacterial altruism” and “Trojan Horse” hypotheses, which are connected to the oxidative stress, are discussed.

  3. Oxidative Stress in Shiga Toxin Production by Enterohemorrhagic Escherichia coli.

    Science.gov (United States)

    Licznerska, Katarzyna; Nejman-Faleńczyk, Bożena; Bloch, Sylwia; Dydecka, Aleksandra; Topka, Gracja; Gąsior, Tomasz; Węgrzyn, Alicja; Węgrzyn, Grzegorz

    2016-01-01

    Virulence of enterohemorrhagic Escherichia coli (EHEC) strains depends on production of Shiga toxins. These toxins are encoded in genomes of lambdoid bacteriophages (Shiga toxin-converting phages), present in EHEC cells as prophages. The genes coding for Shiga toxins are silent in lysogenic bacteria, and prophage induction is necessary for their efficient expression and toxin production. Under laboratory conditions, treatment with UV light or antibiotics interfering with DNA replication are commonly used to induce lambdoid prophages. Since such conditions are unlikely to occur in human intestine, various research groups searched for other factors or agents that might induce Shiga toxin-converting prophages. Among other conditions, it was reported that treatment with H2O2 caused induction of these prophages, though with efficiency significantly lower relative to UV-irradiation or mitomycin C treatment. A molecular mechanism of this phenomenon has been proposed. It appears that the oxidative stress represents natural conditions provoking induction of Shiga toxin-converting prophages as a consequence of H2O2 excretion by either neutrophils in infected humans or protist predators outside human body. Finally, the recently proposed biological role of Shiga toxin production is described in this paper, and the "bacterial altruism" and "Trojan Horse" hypotheses, which are connected to the oxidative stress, are discussed. PMID:26798420

  4. Stochastic switching induced adaptation in a starved Escherichia coli population.

    Science.gov (United States)

    Shimizu, Yoshihiro; Tsuru, Saburo; Ito, Yoichiro; Ying, Bei-Wen; Yomo, Tetsuya

    2011-01-01

    Population adaptation can be determined by stochastic switching in living cells. To examine how stochastic switching contributes to the fate decision for a population under severe stress, we constructed an Escherichia coli strain crucially dependent on the expression of a rewired gene. The gene essential for tryptophan biosynthesis, trpC, was removed from the native regulatory unit, the Trp operon, and placed under the extraneous control of the lactose utilisation network. Bistability of the network provided the cells two discrete phenotypes: the induced and suppressed level of trpC. The two phenotypes permitted the cells to grow or not, respectively, under conditions of tryptophan depletion. We found that stochastic switching between the two states allowed the initially suppressed cells to form a new population with induced trpC in response to tryptophan starvation. However, the frequency of the transition from suppressed to induced state dropped off dramatically in the starved population, in comparison to that in the nourished population. This reduced switching rate was compensated by increasing the initial population size, which probably provided the cell population more chances to wait for the rarely appearing fit cells from the unfit cells. Taken together, adaptation of a starved bacterial population because of stochasticity in the gene rewired from the ancient regulon was experimentally confirmed, and the nutritional status and the population size played a great role in stochastic adaptation. PMID:21931628

  5. Stochastic switching induced adaptation in a starved Escherichia coli population.

    Directory of Open Access Journals (Sweden)

    Yoshihiro Shimizu

    Full Text Available Population adaptation can be determined by stochastic switching in living cells. To examine how stochastic switching contributes to the fate decision for a population under severe stress, we constructed an Escherichia coli strain crucially dependent on the expression of a rewired gene. The gene essential for tryptophan biosynthesis, trpC, was removed from the native regulatory unit, the Trp operon, and placed under the extraneous control of the lactose utilisation network. Bistability of the network provided the cells two discrete phenotypes: the induced and suppressed level of trpC. The two phenotypes permitted the cells to grow or not, respectively, under conditions of tryptophan depletion. We found that stochastic switching between the two states allowed the initially suppressed cells to form a new population with induced trpC in response to tryptophan starvation. However, the frequency of the transition from suppressed to induced state dropped off dramatically in the starved population, in comparison to that in the nourished population. This reduced switching rate was compensated by increasing the initial population size, which probably provided the cell population more chances to wait for the rarely appearing fit cells from the unfit cells. Taken together, adaptation of a starved bacterial population because of stochasticity in the gene rewired from the ancient regulon was experimentally confirmed, and the nutritional status and the population size played a great role in stochastic adaptation.

  6. Expanded flux variability analysis on metabolic network of Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    CHEN Tong; XIE ZhengWei; OUYANG Qi

    2009-01-01

    Flux balance analysis,based on the mass conservation law in a cellular organism,has been extensively employed to study the interplay between structures and functions of cellular metabolic networks.Consequently,the phenotypes of the metabolism can be well elucidated.In this paper,we introduce the Expanded Flux Variability Analysis (EFVA) to characterize the intrinsic nature of metabolic reactions,such as flexibility,modularity and essentiality,by exploring the trend of the range,the maximum and the minimum flux of reactions.We took the metabolic network of Escherichia coli as an example and analyzed the variability of reaction fluxes under different growth rate constraints.The average variability of all reactions decreases dramatically when the growth rate increases.Consider the noise effect on the metabolic system,we thus argue that the microorganism may practically grow under a suboptimal state.Besides,under the EFVA framework,the reactions are easily to be grouped into catabolic and anabolic groups.And the anabolic groups can be further assigned to specific biomass constitute.We also discovered the growth rate dependent essentiality of reactions.

  7. Expression of fully functional tetrameric human hemoglobin in Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, S.J.; Looker, D.L.; Roehrich, J.M.; Cozart, P.E.; Durfee, S.L.; Tedesco, J.L.; Stetler, G.L. (Somatogen, Inc., Broomfield, CO (United States))

    1990-11-01

    Synthesis genes encoding the human {alpha}- and {beta}-globin polypeptides have been expressed from a single operon in Escherichia coli. The {alpha}- and {beta}-globin polypeptides associate into soluble tetramers, incorporate heme, and accumulate to >5% of the total cellular protein. Purified recombinant hemoglobin has the correct stoichiometry of {alpha}- and {beta}-globin chains and contains a full complement of heme. Each globin chain also contains an additional methionine as an extension to the amino terminus. The recombinant hemoglobin has a C{sub 4} reversed-phase HPLC profile essentially identical to that of human hemoglobin A{sub 0} and comigrates with hemoglobin A{sub 0} on SDS/PAGE. The visible spectrum and oxygen affinity are similar to that of native human hemoglobin A{sub 0}. The authors have also expressed the {alpha}- and {beta}-globin genes separately and found that the expression of the {alpha}-globin gene alone results in a marked decrease in the accumulation of {alpha}-globin in the cell. Separate expression of the {beta}-globin gene results in high levels of insoluble {beta}-globin. These observations suggest that the presence of {alpha}- and {beta}-globin in the same cell stabilizes {alpha}-globin and aids the correct folding of {beta}-globin. This system provides a simple method for expressing large quantities of recombinant hemoglobin and allows facile manipulation of the genes encoding hemoglobin to produce functionally altered forms of this protein.

  8. Resolving Holliday junctions with Escherichia coli UvrD helicase.

    Science.gov (United States)

    Carter, Annamarie S; Tahmaseb, Kambiz; Compton, Sarah A; Matson, Steven W

    2012-03-01

    The Escherichia coli UvrD helicase is known to function in the mismatch repair and nucleotide excision repair pathways and has also been suggested to have roles in recombination and replication restart. The primary intermediate DNA structure in these two processes is the Holliday junction. UvrD has been shown to unwind a variety of substrates including partial duplex DNA, nicked DNA, forked DNA structures, blunt duplex DNA and RNA-DNA hybrids. Here, we demonstrate that UvrD also catalyzes the robust unwinding of Holliday junction substrates. To characterize this unwinding reaction we have employed steady-state helicase assays, pre-steady-state rapid quench helicase assays, DNaseI footprinting, and electron microscopy. We conclude that UvrD binds initially to the junction compared with binding one of the blunt ends of the four-way junction to initiate unwinding and resolves the synthetic substrate into two double-stranded fork structures. We suggest that UvrD, along with its mismatch repair partners, MutS and MutL, may utilize its ability to unwind Holliday junctions directly in the prevention of homeologous recombination. UvrD may also be involved in the resolution of stalled replication forks by unwinding the Holliday junction intermediate to allow bypass of the blockage. PMID:22267744

  9. Fast, multiphase volume adaptation to hyperosmotic shock by Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Teuta Pilizota

    Full Text Available All living cells employ an array of different mechanisms to help them survive changes in extra cellular osmotic pressure. The difference in the concentration of chemicals in a bacterium's cytoplasm and the external environment generates an osmotic pressure that inflates the cell. It is thought that the bacterium Escherichia coli use a number of interconnected systems to adapt to changes in external pressure, allowing them to maintain turgor and live in surroundings that range more than two-hundred-fold in external osmolality. Here, we use fluorescence imaging to make the first measurements of cell volume changes over time during hyperosmotic shock and subsequent adaptation on a single cell level in vivo with a time resolution on the order of seconds. We directly observe two previously unseen phases of the cytoplasmic water efflux upon hyperosmotic shock. Furthermore, we monitor cell volume changes during the post-shock recovery and observe a two-phase response that depends on the shock magnitude. The initial phase of recovery is fast, on the order of 15-20 min and shows little cell-to-cell variation. For large sucrose shocks, a secondary phase that lasts several hours adds to the recovery. We find that cells are able to recover fully from shocks as high as 1 Osmol/kg using existing systems, but that for larger shocks, protein synthesis is required for full recovery.

  10. Mutators and hypermutability in bacteria: the Escherichia coli paradigm

    Indian Academy of Sciences (India)

    R. Jayaraman

    2009-12-01

    Mutators (also called hypermutators) are mutants which show higher than normal spontaneous mutation frequencies, ranging from 10–20 fold to 100–1000 fold higher, or sometimes even more, than wild-type cells. Being a mutator is advantageous to the organism when adapting to environmental changes or stressful situations, such as moving from one habitat to another, one host to another, exposure to antibiotics etc. However, this advantage is only a short-term benefit. In the long run, hypermutability leads to a fitness disadvantage due to accumulation of deleterious mutations or antagonistic pleiotropy or both. Contrary to intuitive expectations, hypermutability is commonly encountered in natural bacterial populations, especially among clinical isolates. It is believed to be involved in the emergence of antibiotic resistance and a hindrance to the treatment of infectious diseases. Here, I review the state of knowledge on the common mechanisms of hypermutability such as errors/defects in DNA replication, proof reading, mismatch repair, oxidative DNA damage, mistranslation etc., as well as phenomena associated with these processes, using Escherichia coli as a paradigmatic organism.

  11. Molecular detection and identification of intimin alleles in pathogenic Escherichia coli by multiplex PCR.

    Science.gov (United States)

    Reid, S D; Betting, D J; Whittam, T S

    1999-08-01

    A multiplex PCR was designed to detect the eae gene and simultaneously identify specific alleles in pathogenic Escherichia coli. The method was tested on 87 strains representing the diarrheagenic E. coli clones. The results show that the PCR assay accurately detects eae and resolves alleles encoding the alpha, beta, and gamma intimin variants. PMID:10405431

  12. Vicinal Dithiol-Disulfide Distribution in the Escherichia coli Mannitol Specific Carrier Enzyme IImtl

    NARCIS (Netherlands)

    Roossien, F.F.; Robillard, G.T.

    1984-01-01

    Escherichia coli mannitol specific EII in membrane vesicles can be inhibited by the action of the oxidizable substrate-reduced phenazine methosulfate (PMS) in a manner similar to E. coli enzyme IIGlc. The fact that reduced PMS and various oxidizing agents protect the enzyme from inactivation by the

  13. Phosphoribosylpyrophosphate (PRPP)-less mutants of Escherichia coli

    DEFF Research Database (Denmark)

    Hove-Jensen, Bjarne

    1989-01-01

    A DNA fragment encoding kanamycin resistance was inserted in vitro into a plasmid-borne prs gene encoding phosphoribosylpyrophosphate synthetase of Escherichia coli. The resulting plasmids were subsequently transferred to the chromosome by homologous recombination and the haploid strains prs-3::Kan...... phosphoribosylpyrophosphate synthetase is dispensable for E. coli....

  14. DNA probes for K-antigen (capsule) typing of Escherichia coli.

    OpenAIRE

    Roberts, M.; Roberts, I.; Korhonen, T K; Jann, K; Bitter-Suermann, D; Boulnois, G J; Williams, P H

    1988-01-01

    DNA restriction fragments derived from the polysaccharide biosynthesis regions of cloned Escherichia coli K1, K5, and K12 capsular antigen genes hybridized only with DNA of strains determined by conventional methods to be of the same K serotype. A probe derived from the common transport region hybridized to all encapsulated E. coli strains.

  15. Establishing Streptomycin Epidemiological Cut-Off Values for Salmonella and Escherichia coli

    DEFF Research Database (Denmark)

    Migura, Lourdes Garcia; Sunde, Marianne; Karlsmose, Susanne;

    2011-01-01

    This study was conducted to elucidate the accuracy of the current streptomycin epidemiological cut-off value (ECOFF) for Escherichia coli and Salmonella spp. A total of 236 Salmonella enterica and 208 E. coli isolates exhibiting MICs between 4 and 32 mg/L were selected from 12 countries. Isolates...

  16. Rapid Extraction of DNA From Escherichia coli and Cryptosporidium parvum for Use in PCR

    OpenAIRE

    Higgins, James A.; Jenkins, Mark C.; Shelton, Daniel R.; Fayer, Ron; Karns, Jeffrey S.

    2001-01-01

    The Xtra Amp tube, Isocode paper, Instagene matrix, and PrepMan matrix methods were evaluated for their ability to rapidly extract PCR-quality DNAs from Escherichia coli O157:H7 and Cryptosporidium parvum. All methods provided satisfactory DNA from E. coli, and the Xtra Amp and Instagene reagents provided satisfactory DNA from C. parvum.

  17. Mechanisms of Reduced Susceptibility to Ciprofloxacin in Escherichia coli Isolates from Canadian Hospitals

    Directory of Open Access Journals (Sweden)

    Patricia J Baudry-Simner

    2012-01-01

    Full Text Available OBJECTIVE: To determine whether plasmid-mediated quinolone resistance (PMQR determinants play a role in the increasing resistance to fluoroquinolones among Escherichia coli isolates in Canadian hospitals, and to determine the mechanisms of reduced susceptibility to ciprofloxacin in a recent collection of 190 clinical E coli isolates.

  18. Complete genome sequence and comparison of two Shiga toxin-producing Escherichia coli O104 isolates

    Science.gov (United States)

    Shiga toxin-producing Escherichia coli (STEC) O104 strains have been associated with sporadic cases of illness and have caused outbreaks associated with milk and sprouts. E. coli O104:H21 caused an outbreak associated with milk in the U.S. in 1994. In this study, next generation sequencing techno...

  19. Efficacy of supercritical carbon dioxide for nonthermal inactivation of Escherichia coli K12 in apple cider

    Science.gov (United States)

    This study evaluated the efficacy of a supercritical carbon dioxide (SCCO2) system with a gas-liquid porous metal contactor for eliminating Escherichia coli K12 in apple cider. Pasteurized, preservative-free apple cider was inoculated with E. coli K12 and processed using the SCCO2 system at CO2 conc...

  20. Crude extract of maggots: Antibacterial effects against Escherichia coli, underlying mechanisms, separation and purification

    OpenAIRE

    Ge, Quan-Sheng; Zhang, Hui-Min; Liu, Xia; Wang, Shou-Yu; Lv, De-Cheng; LI, Xu-dong

    2015-01-01

    AIM: To investigate the antibacterial effects of a crude extract of maggots against Escherichia coli (E. coli) and the underlying mechanisms, and to separate and purify the crude extract of maggots to assess the antibacterial effects of the active ingredients in the crude extract.

  1. Proliferation of Escherichia coli O157:H7 in soil and hydroponic microgreen production systems

    Science.gov (United States)

    Radish (Raphanus sativus var. longipinnatus) microgreens were produced from seeds inoculated with Escherichia coli O157: H7 using soil substitute and hydroponic production systems. E. coli populations on the edible and inedible parts of harvested microgreen plants and in growth medium were examined....

  2. Identification of Escherichia coli O157 by Using a Novel Colorimetric Detection Method with DNA Microarrays

    Science.gov (United States)

    Shiga toxin-producing Escherichia coli O157:H7 is a leading cause of foodborne illness worldwide. To evaluate better methods to rapidly detect and genotype E. coli O157 strains, the present study evaluated the use of ampliPHOX, a novel colorimetric detection method based on photopolymerization, for...

  3. Effects of media on recovery of Escherichia coli 0157:H7 and Pseudomonas fluorescens from spinach

    Science.gov (United States)

    Control the post-harvest contamination of leafy greens by Escherichia coli O157:H7 is important for food safety. Efficient recovery and enumeration of E. coli O157:H7 and the biocontrol microbe Pseudomonas fluorescens from produce is crucial for assessment of biocontrol efficacy. Sensitive and effec...

  4. Recovery of Escherichia coli from Soil after Addition of Sterile Organic Wastes

    OpenAIRE

    Unc, Adrian; Gardner, Julie; Springthorpe, Susan

    2006-01-01

    Laboratory batch tests indicate that addition of sterile municipal sewage biosolids to clay soil from four depths increases the numbers of Escherichia coli isolates recoverable in EC-MUG broth (EC broth with 4-methylumbelliferyl-β-glucuronide). This effect was most marked for the deeper soil layers, with increases of about 2.6 orders of magnitude in E. coli most probable number.

  5. Haemolytic Escherichia coli isolated from dogs with diarrhea have characteristics of both uropathogenic and necrotoxigenic strains

    NARCIS (Netherlands)

    Starxix, M.; Johnson, J.R.; Stell, A.L.; Goot, van der J.A.; Hendriks, H.G.; Vorstenbosch, van C.; Dijk, van L.; Gaastra, W.

    2002-01-01

    Twenty-four haemolytic Escherichia coli strains were isolated from dogs with diarrhea. The strains were serotyped and analysed by polymerase chain reaction (PCR) for genes encoding virulence factors associated with E. coli that cause diarrhea in animals. Adhesion antigen production was deduced from

  6. Molecular cloning of the Salmonella typhimurium lep gene in Escherichia coli

    NARCIS (Netherlands)

    van Dijl, J M; van den Bergh, R; Reversma, T; Smith, H; Bron, S; Venema, G

    1990-01-01

    A system is described which enabled the selection of a heterologous lep gene, encoding signal peptidase I, in Escherichia coli. It is based on complementation of an E. coli mutant, in which the synthesis of signal peptidase I can be regulated. With this system the lep gene of Salmonella typhimurium

  7. Non-functional expression of Escherichia coli signal peptidase I in Bacillus subtilis

    NARCIS (Netherlands)

    van Dijl, J M; de Jong, A; Smith, H; Bron, S; Venema, G

    1991-01-01

    The Escherichia coli lep gene, encoding signal peptidase I (SPase I) was provided with Bacillus subtilis transcription/translation signals and expressed in this organism. When present on a low-copy-number plasmid, the amount of E. coli SPase I produced (per mg cell protein) in B. subtilis was half t

  8. Serogroups and antimicrobial susceptibility among Escherichia coli isolated from farmed mink (Mustela vison Schreiber) in Denmark

    DEFF Research Database (Denmark)

    Vulfson, L.; Pedersen, Karl; Chriel, M.; Frydendahl, K.; Andersen, T.H.; Madsen, Mogens; Dietz, H.H.

    2001-01-01

    Escherichia coli is commonly found in outbreaks of diarrhoea in mink during the production season although its role as a primary causal organism remains unclear. The present study was undertaken to determine the serogroups and antimicrobial susceptibility of E. coli isolates from healthy and diar...

  9. Impact of Diversity of Colonizing Strains on Strategies for Sampling Escherichia coli from Fecal Specimens ▿

    OpenAIRE

    Lautenbach, Ebbing; Bilker, Warren B.; Tolomeo, Pam; Maslow, Joel N.

    2008-01-01

    Of 49 subjects, 21 were colonized with more than one strain of Escherichia coli and 12 subjects had at least one strain present in fewer than 20% of colonies. The ability to accurately characterize E. coli strain diversity is directly related to the number of colonies sampled and the underlying prevalence of the strain.

  10. Impact of Diversity of Colonizing Strains on Strategies for Sampling Escherichia coli from Fecal Specimens ▿

    Science.gov (United States)

    Lautenbach, Ebbing; Bilker, Warren B.; Tolomeo, Pam; Maslow, Joel N.

    2008-01-01

    Of 49 subjects, 21 were colonized with more than one strain of Escherichia coli and 12 subjects had at least one strain present in fewer than 20% of colonies. The ability to accurately characterize E. coli strain diversity is directly related to the number of colonies sampled and the underlying prevalence of the strain. PMID:18650357

  11. Quantification of survival of Escherichia coli 0157:H7 on Plants affected by Contaminated Irrigation Water

    Science.gov (United States)

    Enterohemorrhagic E. coli O157: H7 (EHEC) is a major foodborne pathogen capable of causing diarrhea and vomiting, with further complications such as hemolytic-uremic syndrome (HUS). The aim of this study was to use real-time PCR method to quantify the survival of Escherichia coli O157:H7/pGFP in phy...

  12. Antibiotic Resistance in Diarrheagenic Escherichia coli and Shigella Strains Isolated from Children in Hanoi, Vietnam

    OpenAIRE

    Nguyen, Trung Vu; Le Van, Phung; Le, Chinh Huy; Weintraub, Andrej

    2005-01-01

    The MICs for 162 diarrheagenic Escherichia coli strains and 28 Shigella strains were determined on the basis of NCCLS guidelines. More than 75% of the strains were resistant to ampicillin, chloramphenicol (53.6% of Shigella strains), and trimethoprim-sulfamethoxazole. Multiresistance was detected in 89.5% of E. coli strains and 78.6% of Shigella strains.

  13. Heterologous Carotenoid-Biosynthetic Enzymes: Functional Complementation and Effects on Carotenoid Profiles in Escherichia coli

    OpenAIRE

    Song, Gyu Hyeon; Kim, Se Hyeuk; Choi, Bo Hyun; Han, Se Jong; Lee, Pyung Cheon

    2013-01-01

    A limited number of carotenoid pathway genes from microbial sources have been studied for analyzing the pathway complementation in the heterologous host Escherichia coli. In order to systematically investigate the functionality of carotenoid pathway enzymes in E. coli, the pathway genes of carotenogenic microorganisms (Brevibacterium linens, Corynebacterium glutamicum, Rhodobacter sphaeroides, Rhodobacter capsulatus, Rhodopirellula baltica, and Pantoea ananatis) were modified to form syntheti...

  14. Proteomic analysis reveals protein expression differences in Escherichia coli strains associated with persistent versus transient mastitis

    Science.gov (United States)

    Escherichia coli is a leading cause of bacterial mastitis in dairy cattle. Typically this infection is transient in nature, causing an infection that lasts 2-3 days. However, in a minority of cases, E. coli has been shown to cause a persistent intramammary infection. The mechanisms that allow for...

  15. beta-Chloro-L-alanine inhibition of the Escherichia coli alanine-valine transaminase.

    OpenAIRE

    Whalen, W A; Wang, M D; Berg, C M

    1985-01-01

    beta-Chloro-L-alanine, an amino acid analog which inhibits a number of enzymes, reversibly inhibited the Escherichia coli K-12 alanine-valine transaminase, transaminase C. This inhibition, along with the inhibition of transaminase B, accounted for the isoleucine-plus-valine requirement of E. coli in the presence of beta-chloro-L-alanine.

  16. Dissociation of outer membrane for Escherichia coli cell caused by cerium nitrate

    Institute of Scientific and Technical Information of China (English)

    陈爱美; 施庆珊; 冯劲; 欧阳友生; 陈仪本; 谭绍早

    2010-01-01

    The biological effect of cerium nitrate on the outer membrane(OM) of Escherichia coli(E.coli) cell was studied,and the antim-icrobial mechanism of rare earth elements was explored.The antimicrobial effect of cerium nitrate on E.coli cell was valued by plate count method,and the morphology change of E.coli cell was observed with scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The results showed that the E.coli cell suspension was flocculated when the concentration of Ce(NO3)3?6H2O...

  17. Transduction of Enteric Escherichia coli Isolates with a Derivative of Shiga Toxin 2-Encoding Bacteriophage φ3538 Isolated from Escherichia coli O157:H7

    OpenAIRE

    Schmidt, Herbert; Bielaszewska, Martina; Karch, Helge

    1999-01-01

    We investigated the ability of a detoxified derivative of a Shiga toxin 2 (Stx2)-encoding bacteriophage to infect and lysogenize enteric Escherichia coli strains and to develop infectious progeny from such lysogenized strains. The stx2 gene of the patient E. coli O157:H7 isolate 3538/95 was replaced by the chloramphenicol acetyltransferase (cat) gene from plasmid pACYC184. Phage φ3538(Δstx2::cat) was isolated after induction of E. coli O157:H7 strain 3538/95 with mitomycin. A variety of strai...

  18. Nonpathogenic Escherichia coli Strain Nissle 1917 Inhibits Signal Transduction in Intestinal Epithelial Cells▿

    OpenAIRE

    Kamada, Nobuhiko; Maeda, Kenichi; Inoue, Nagamu; Hisamatsu, Tadakazu; Okamoto, Susumu; Hong, Kyong Su; Yamada, Takaya; Watanabe, Noriaki; Tsuchimoto, Kanji; Ogata, Haruhiko; Hibi, Toshifumi

    2007-01-01

    Although the probiotic Escherichia coli strain Nissle 1917 has been used for the treatment of inflammatory bowel diseases, the precise mechanisms of action of this strain remain unclear. In the present study, we estimated the anti-inflammatory effect of E. coli Nissle 1917 on inflammatory responses in vitro to determine the suppressive mechanism of Nissle 1917 on the inflammatory process. To determine the effect of E. coli Nissle 1917, the human colonic epithelial cell line HCT15 was incubate...

  19. Tissue distribution of a coliphage and Escherichia coli in mussels after contamination and depuration.

    OpenAIRE

    Power, U.F.; Collins, J K

    1990-01-01

    Experiments were undertaken to determine the tissue distribution of Escherichia coli and a coliphage after contamination of the common mussel (Mytilus edulis). Mussels were contaminated with high levels of feces-associated E. coli and a 22-nm icosahedral coliphage over a 2-day period in a flowing-seawater facility. After contamination, individual tissues were carefully dissected and assayed for E. coli and the coliphage. Contaminated mussels were also analyzed to determine the tissue distribu...

  20. Virulence factors and drug resistance in Escherichia coli isolated from extraintestinal infections

    OpenAIRE

    Sharma S; Bhat G; Shenoy S

    2007-01-01

    Purpose: To determine the virulence factors produced by Escherichia coli isolated from extraintestinal infections, to study the drug resistance pattern in E. coli with special reference to extended spectrum β -lactamase (ESBL) and to evaluate screening methods for ESBL. Methods: A total of 152 isolates of E. coli from various extraintestinal infections were screened for virulence factors such as haemolysin, surface hydrophobicity, serum resistance and protease. All the isolates ...

  1. Escherichia coli as an indicator of bacteriological quality of water: an overview

    OpenAIRE

    Stephen T. Odonkor; Joseph K. Ampofo

    2013-01-01

    Monitoring the microbiological quality of drinking water relies largely on examination of indicator bacteria such as coliforms, Escherichia coli, and Pseudomonas aeruginosa. E. coli is a member of the faecal coliform group and is a more specific indicator of faecal pollution than other faecal coliforms. Two key factors have led to the trend toward the use of E. coli as the preferred indicator for the detection of faecal contamination, not only in drinking water, but also in other matrices as ...

  2. Cloning and surface expression of Pseudomonas aeruginosa O antigen in Escherichia coli.

    OpenAIRE

    Goldberg, J B; Hatano, K; Meluleni, G S; Pier, G B

    1992-01-01

    As a step toward developing recombinant oral vaccines, we have explored the feasibility of expression of O polysaccharide antigens from Pseudomonas aeruginosa by Escherichia coli. We cloned in E. coli HB101 a 26.2-kilobase DNA fragment from P. aeruginosa strain PA103 that specifies the production of the O polysaccharide of Fisher immunotype 2 (IT-2) strains. The recombinant organism incorporated the P. aeruginosa IT-2 O polysaccharide onto the core of the E. coli lipopolysaccharide (LPS). Tra...

  3. Prevalence of Shiga toxin genes and intimin genes in uropathogenic Escherichia coli

    OpenAIRE

    Kobra Abbasi; Elahe Tajbakhsh

    2015-01-01

    Objective: To identify stx1, stx2 and eaeA genes in Escherichia coli (E. coli) strains isolated from urine samples in Shahrekord, Iran. Methods: In this cross study a total of 147 middle urine samples from patients with symptoms of urinary tract infection (UTI), referred to clinical laboratories of Shahrekord were studied. Taken samples were cultured to detect Shigatoxin-producing strains and finally 76 E. coli isolates were identified using the standard biochemical tests as we...

  4. Engineering Escherichia Coli Fatty Acid Metabolism for the Production of Biofuel Precursors

    OpenAIRE

    Ford, Tyler John

    2015-01-01

    Medium chain fatty acids (MCFAs, 6-12 carbons) are potential precursors to biofuels with properties similar to gasoline and diesel fuel but are not native products of Escherichia coli fatty acid synthesis. Herein we engineer E. coli to produce, metabolize, and activate MCFAs for their future reduction into alcohols and alkanes (potential biofuels). We develop an E. coli strain with an octanoate (8-carbon MCFA) producing enzyme (a thioesterase), metabolic knockouts, and the capa...

  5. Exposure to the Proton Scavenger Glycine under Alkaline Conditions Induces Escherichia coli Viability Loss

    OpenAIRE

    Donna Vanhauteghem; Geert Paul Jules Janssens; Angelo Lauwaerts; Stanislas Sys; Filip Boyen; Eric Cox; Evelyne Meyer

    2013-01-01

    Our previous work described a clear loss of Escherichia coli (E. coli) membrane integrity after incubation with glycine or its N-methylated derivatives N-methylglycine (sarcosine) and N,N-dimethylglycine (DMG), but not N,N,N-trimethylglycine (betaine), under alkaline stress conditions. The current study offers a thorough viability analysis, based on a combination of real-time physiological techniques, of E. coli exposed to glycine and its N-methylated derivatives at alkaline pH. Flow cytometr...

  6. Antibiotic Resistance Patterns in Enteric and Uropathogenic Strains of Escherichia Coli in Children

    OpenAIRE

    This paper should be cited as: Sedighi I, Alikhani MY, Nakhaee S, Karami P . [ Antibiotic Resistance Patterns in Enteric and Uropathogenic Strains of Escherichia Coli in Children ]. mlj goums . 201 4 ; 8 ( Suppl 4 ): 42 - 48 [Article in Per sian] Sedi ghi, I. (MD); Alikhani, MY. (PhD); Nakhaee, S. (MD); Karami, P. (MSc

    2014-01-01

    Background and Objective: Escherichia coli is the most common cause of urinary tract infections in children and the leading cause of intra-abdominal infections (peritonitis and abscess) followed intestinal injuries. Urinary tract infection, including cystitis and pyelonephritis, is a common childhood infection. E. coli causes more than 90 percent of the community acquired and 50% of hospital acquired urinary tract infections; therefore, the determination of E. coli antibiotic susceptibility i...

  7. Characterization of Unexpected Growth of Escherichia coli O157:H7 by Modeling

    OpenAIRE

    Cornu, Marie; Delignette-Muller, Marie Laure; Flandrois, Jean-Pierre

    1999-01-01

    Modeling of batch kinetics in minimal synthetic medium was used to characterize Escherichia coli O157:H7 growth, which appeared to be different from the exponential growth expected in minimal synthetic medium and observed for E. coli K-12. The turbidimetric kinetics of 14 of the 15 O157:H7 strains tested (93%) were nonexponential, whereas 25 of the 36 other E. coli strains tested (70%) exhibited exponential kinetics. Moreover, the anomaly was almost corrected when the minimal medium was suppl...

  8. Colonization with Extraintestinal Pathogenic Escherichia coli among Nursing Home Residents and Its Relationship to Fluoroquinolone Resistance

    Science.gov (United States)

    Maslow, Joel N.; Lautenbach, Ebbing; Glaze, Thomas; Bilker, Warren; Johnson, James R.

    2004-01-01

    In a cross-sectional fecal prevalence survey involving 49 residents of a Veterans Affairs nursing home, 59% of subjects were colonized with extraintestinal pathogenic Escherichia coli (ExPEC), 22% were colonized with adhesin-positive E. coli, and 51% were colonized with fluoroquinolone-resistant E. coli. Among 80 unique isolates, adhesins correlated negatively and aerobactin correlated positively with fluoroquinolone resistance. PMID:15328142

  9. Solar and Temporal Effects on Escherichia coli Concentration at a Lake Michigan Swimming Beach†

    OpenAIRE

    Whitman, Richard L.; Nevers, Meredith B.; Korinek, Ginger C.; Byappanahalli, Muruleedhara N.

    2004-01-01

    Studies on solar inactivation of Escherichia coli in freshwater and in situ have been limited. At 63rd St. Beach, Chicago, Ill., factors influencing the daily periodicity of culturable E. coli, particularly insolation, were examined. Water samples for E. coli analysis were collected twice daily between April and September 2000 three times a week along five transects in two depths of water. Hydrometeorological conditions were continuously logged: UV radiation, total insolation, wind speed and ...

  10. Development of a Procedure for Discriminating among Escherichia coli Isolates from Animal and Human Sources

    OpenAIRE

    Guan, Shukui; Xu, Renlin; Chen, Shu; Odumeru, Joseph; Gyles, Carlton

    2002-01-01

    Counts of Escherichia coli cells in water indicate the potential presence of pathogenic microbes of intestinal origin but give no indication of the sources of the microbial pollution. The objective of this research was to evaluate methods for differentiating E. coli isolates of livestock, wildlife, or human origin that might be used to predict the sources of fecal pollution of water. A collection of 319 E. coli isolates from the feces of cattle, poultry, swine, deer, goose, and moose, as well...

  11. DNA Hybridization of Escherichia coli Strains Isolated from Uteri and Fecal Samples of Bitches with Pyometra

    OpenAIRE

    SANCAK, Aziz Arda

    2004-01-01

    Escherichia coli is the most common bacterium that has been isolated from the bacterial culture of uterine and fecal samples of dogs with pyometra. The aim of the present study was to determine whether this organism could be relevant to the pathogenesis of pyometra in dogs. Fecal and uterine samples were collected from 17 bitches with pyometra. E. coli strains were isolated in all samples. Representative colonies of E. coli from each sample were analyzed for pathogenicity determinants by h...

  12. Enterohaemorrhagic Escherichia coli O157: a survey of dairy cattle in Tripoli, Libya

    OpenAIRE

    Ahmed, Mohamed O; Abouzeed, Yousef M

    2014-01-01

    Zoonotic Escherichia coli O157 pathogen represents a serious threat to human health. To investigate the occurrence and prevalence of E. coli O157 among the dairy cattle of Tripoli, Libya, fecal samples were collected intrarectally from 97 outwardly healthy animals and tested by selective plating (Sorbitol-MacConkey agar), biochemical testing (API20E bacterial identification system), and specific antigen detection (latex agglutination test). E. coli O157 were identified and confirmed in 6% (7/...

  13. High Rates of Escherichia coli Transmission between Livestock and Humans in Rural Uganda▿

    OpenAIRE

    Innocent B Rwego; Gillespie, Thomas R.; Isabirye-Basuta, Gilbert; Goldberg, Tony L.

    2008-01-01

    Escherichia coli is a zoonotic bacterium that is important to both public health and livestock economics. To date, most studies of zoonotic E. coli transmission have been conducted in developed nations with industrialized agricultural economies. In this study, E. coli bacteria were collected from people and livestock in two communities in rural western Uganda in order to investigate patterns of interspecific bacterial transmission in a developing rural economy characterized by very close huma...

  14. Culture confirmation of Escherichia coli serotype O157:H7 by direct immunofluorescence.

    OpenAIRE

    Tison, D. L.

    1990-01-01

    An evaluation of a fluorescein-labeled, polyclonal, affinity-purified goat antibody to Escherichia coli serotype O157:H7 (Kirkegaard & Perry Laboratories Inc., Gaithersburg, Md.) was conducted to determine the efficacy of this research reagent for the rapid direct immunofluorescence identification of E. coli O157:H7 isolated from fecal specimens cultured on sorbitol-MacConkey (SMAC) agar. The E. coli O157:H7 fluorescent-antibody conjugate proved to be 100% sensitive and specific for the rapid...

  15. Investigating the Antibacterial Effects of Plant Extracts on Pseudomonas aeruginosa and Escherichia coli

    Directory of Open Access Journals (Sweden)

    Jahani

    2016-04-01

    Full Text Available Background Scientists are seeking an appropriate alternative method for curing infections caused by resistant bacteria, since drug resistance is continually increasing. Objectives This research aims to discover the function of some medicine plants on pestiferous Pseudomonas aeruginosa and Escherichia coli in humans. Materials and Methods Bacterial strains were obtained from a standard laboratory. The strains of Pseudomonas aeruginosa ATCC27853 and E.coli ATCC25922 bacteria were used for antimicrobial testing of the extractions. Results Our results showed that Teucrium polium extracts have the minimum density of inhibitory for Escherichia coli, 25 ppm, whereas the maximum of this is for Peganum harmala and Prangos ferulaceae with 100 ppm. The lowest minimum concentration inhibitory value of extracts P. harmala, T. polium, T. pratensis and Rumex was found in 25 ppm against P.aeruginosa. Conclusions The results of our study showed that plant extracts have good antibacterial properties against Pseudomonas aeruginosa and Escherichia coli.

  16. Antibiotic Resistance Patterns in Enteric and Uropathogenic Strains of Escherichia Coli in Children

    Directory of Open Access Journals (Sweden)

    This paper should be cited as: Sedighi I, Alikhani MY, Nakhaee S, Karami P . [ Antibiotic Resistance Patterns in Enteric and Uropathogenic Strains of Escherichia Coli in Children ]. mlj goums . 201 4 ; 8 ( Suppl 4 : 42 - 48 [Article in Per sian] Sedi ghi, I. (MD

    2014-11-01

    Full Text Available Background and Objective: Escherichia coli is the most common cause of urinary tract infections in children and the leading cause of intra-abdominal infections (peritonitis and abscess followed intestinal injuries. Urinary tract infection, including cystitis and pyelonephritis, is a common childhood infection. E. coli causes more than 90 percent of the community acquired and 50% of hospital acquired urinary tract infections; therefore, the determination of E. coli antibiotic susceptibility is a paramount importance to clinical and epidemiological purposes. Material and Methods: In this cross-sectional study, 50 E. coli strains isolated from urine samples of children less than 7 years of age with urinary tract infections. They were compared for drug susceptibility testing by disc diffusion method with 50 strains of Escherichia coli isolated from stool samples of healthy children with the same age and sex pattern. Results: The actual amount of drug sensitivity of uropathogenic and intestinal Escherichia coli strains to amikacin was 94 and 100%, nitrofurantoin 90 and 88%, gentamicin 66 and 94%, cefixime 56 and 60%, nalidixic acid 38 and 44% and to cotrimoxazole 28 and 32%, respectively. Conclusion: the rate of resistance to gentamicin, Cefixime and nalidixic acid in urinary tract infection isolates were more than intestinal strains. The highest rate of drug resistance in urinary Escherichia coli isolates was associated with cotrimoxazole and the lowest one with amikacin.

  17. Molecular characterization of bacteremic Escherichia coli isolates in Romania.

    Science.gov (United States)

    Usein, Codruţa-Romaniţa; Papagheorghe, Raluca; Oprea, Mihaela; Condei, Maria; Strãuţ, Monica

    2016-05-01

    The increasing prevalence of invasive infections caused by antibiotic resistant Escherichia coli strains in Romanian patients, already mentioned in the European reports, requires better knowledge of their specific traits. Thus, a set of 38 E. coli blood isolates, collected between 2010 and 2012 at one of the local hospitals participating into the European Antimicrobial Resistance Surveillance Network, was investigated retrospectively with respect to the phylogenetic origin, extraintestinal virulence-associated markers (i.e. fimH, papC, papG alleles, sfa/foc, afa/dra, hly, cnf1, sat, iucC, fyuA, ibeA), and beta-lactamase encoding genes (i.e. bla CTX-M, bla TEM, and bla SHV alleles). The isolates with extended-spectrum beta-lactamase (ESBL) phenotypes were further characterized using PCR-based replicon typing and multilocus sequencing typing. For ST131 members, pulsed-field gel electrophoresis (PFGE) and PCR-based detection of fimH30 allele were performed. Overall, the isolates were more likely members of the major phylogenetic group A (53 %) and to a lesser extent of groups B2 (29 %), D (10 %), and B1 (8 %). All but three of the virulence markers sought (i.e. papGI, hly, cnf1) were detected with prevalence ranging from 3 % (i.e. ibeA, papGIII) to 87 % (fimH). As expected, the most complex genotypes (four to seven virulence markers) defined the isolates derived from phylogenetic groups B2 and D. ESBL producers were bla CTX-M-15-positive, mostly of phylogroup A (67 %), harboured IncF multireplicon plasmids, and belonged to six sequence types (i.e. ST10, ST131, ST167, ST410, ST540, ST1275). Members of ST10 clonal complex (i.e. ST10, ST167) were the most common. The ST131 isolates belonged to H30 subclone and displayed 74 % similarity at PFGE analysis. PMID:26452764

  18. A Comparative Analysis of the Mechanism of Toll-Like Receptor-Disruption by TIR-Containing Protein C from Uropathogenic Escherichia coli.

    Science.gov (United States)

    Waldhuber, Anna; Snyder, Greg A; Römmler, Franziska; Cirl, Christine; Müller, Tina; Xiao, Tsan Sam; Svanborg, Catharina; Miethke, Thomas

    2016-01-01

    The TIR-containing protein C (TcpC) of uropathogenic Escherichia coli strains is a powerful virulence factor by impairing the signaling cascade of Toll-like receptors (TLRs). Several other bacterial pathogens like Salmonella, Yersinia, Staphylococcus aureus but also non-pathogens express similar proteins. We discuss here the pathogenic potential of TcpC and its interaction with TLRs and TLR-adapter proteins on the molecular level and compare its activity with the activity of other bacterial TIR-containing proteins. Finally, we analyze and compare the structure of bacterial TIR-domains with the TIR-domains of TLRs and TLR-adapters. PMID:26938564

  19. A Comparative Analysis of the Mechanism of Toll-Like Receptor-Disruption by TIR-Containing Protein C from Uropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Anna Waldhuber

    2016-02-01

    Full Text Available The TIR-containing protein C (TcpC of uropathogenic Escherichia coli strains is a powerful virulence factor by impairing the signaling cascade of Toll-like receptors (TLRs. Several other bacterial pathogens like Salmonella, Yersinia, Staphylococcus aureus but also non-pathogens express similar proteins. We discuss here the pathogenic potential of TcpC and its interaction with TLRs and TLR-adapter proteins on the molecular level and compare its activity with the activity of other bacterial TIR-containing proteins. Finally, we analyze and compare the structure of bacterial TIR-domains with the TIR-domains of TLRs and TLR-adapters.

  20. The Probiotic Escherichia coli Nissle 1917 Reduces Pathogen Invasion and Modulates Cytokine Expression in Caco-2 Cells Infected with Crohn's Disease-Associated E. coli LF82 ▿

    OpenAIRE

    Huebner, Claudia; Ding, Yaoyao; Petermann, Ivonne; Knapp, Christoph; Ferguson, Lynnette R.

    2011-01-01

    Increased numbers of adherent invasive Escherichia coli (AIEC) have been found in Crohn's disease (CD) patients. In this report, we investigate the potential of the probiotic Escherichia coli Nissle 1917 (EcN) to reduce features associated with AIEC pathogenicity in an already established infection with AIEC reference strain LF82.