WorldWideScience

Sample records for escherichia coli exhibits

  1. Tellurite-exposed Escherichia coli exhibits increased intracellular {alpha}-ketoglutarate

    Energy Technology Data Exchange (ETDEWEB)

    Reinoso, Claudia A. [Departamento de Biologia, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, Santiago (Chile); Auger, Christopher; Appanna, Vasu D. [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario (Canada); Vasquez, Claudio C., E-mail: claudio.vasquez@usach.cl [Departamento de Biologia, Facultad de Quimica y Biologia, Universidad de Santiago de Chile, Santiago (Chile)

    2012-05-18

    Highlights: Black-Right-Pointing-Pointer Tellurite-exposed E. coli exhibits decreased {alpha}-KG dehydrogenase activity. Black-Right-Pointing-Pointer Cells lacking {alpha}-KGDH genes are more sensitive to ROS than isogenic, wt E. coli. Black-Right-Pointing-Pointer KG accumulation may serve to face tellurite-mediated oxidative damage in E. coli. -- Abstract: The tellurium oxyanion tellurite is toxic to most organisms because of its ability to generate oxidative stress. However, the detailed mechanism(s) how this toxicant interferes with cellular processes have yet to be fully understood. As part of our effort to decipher the molecular interactions of tellurite with living systems, we have evaluated the global metabolism of {alpha}-ketoglutarate a known antioxidant in Escherichia coli. Tellurite-exposed cells displayed reduced activity of the KG dehydrogenase complex (KGDHc), resulting in increased intracellular KG content. This complex's reduced activity seems to be due to decreased transcription in the stressed cells of sucA, a gene that encodes the E1 component of KGDHc. Furthermore, it was demonstrated that the increase in total reactive oxygen species and superoxide observed upon tellurite exposure was more evident in wild type cells than in E. coli with impaired KGDHc activity. These results indicate that KG may be playing a pivotal role in combating tellurite-mediated oxidative damage.

  2. Escherichia coli

    Science.gov (United States)

    Alizade, Hesam

    2018-01-01

    Escherichia coli is the most prominent cause of infectious diseases that span from the gastrointestinal tract to extra-intestinal sites such as urinary tract infection, septicaemia, and neonatal meningitis. The emergence and spread of antibiotic resistance in E. coli is an increasing public health concern across the world. Rising resistance in E. coli isolates is also observed in Iran. This review summarizes the status of antibiotic resistance of E. coli isolates in Iran from 2007 to 2016. The data of the prevalence of E. coli antibiotic resistance were collected from databases such as Web of Science, PubMed, Scopus, Embase, Cochrane Library, Google Scholar and Scientific Information Database. Antibiotic resistance in E. coli is on the rise. Prevalence of antibiotic resistance of E. coli varies from region to region in Iran.

  3. 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…

  4. Genes regulated by the Escherichia coli SOS repressor LexA exhibit heterogenous expression

    Directory of Open Access Journals (Sweden)

    Gillor Osnat

    2010-11-01

    Full Text Available Abstract Background Phenotypic heterogeneity may ensure that a small fraction of a population survives environmental perturbations or may result in lysis in a subpopulation, to increase the survival of siblings. Genes involved in DNA repair and population dynamics play key roles in rapid responses to environmental conditions. In Escherichia coli the transcriptional repressor LexA controls a coordinated cellular response to DNA damage designated the SOS response. Expression of LexA regulated genes, e.g. colicin encoding genes, recA, lexA and umuDC, was examined utilizing transcription fusions with the promoterless gfp at the single cell level. Results The investigated LexA regulated genes exhibited heterogeneity, as only in a small fraction of the population more intense fluorescence was observed. Unlike recA and lexA, the pore forming and nuclease colicin activity genes as well as umuDC, exhibited no basal level activity. However, in a lexA defective strain high level expression of the gene fusions was observed in the large majority of the cells. All of the investigated genes were expressed in a recA defective strain, albeit at lower levels, revealing expression in the absence of a spontaneous SOS response. In addition, the simultaneous expression of cka, encoding the pore forming colicin K, and lexA, investigated at the single cell level revealed high level expression of only cka in rare individual cells. Conclusion LexA regulated genes exhibit phenotypic heterogeneity as high level expression is observed in only a small subpopulation of cells. Heterogenous expression is established primarily by stochastic factors and the binding affinity of LexA to SOS boxes.

  5. Chloramphenicol- and tetracycline-resistant uropathogenic Escherichia coli (UPEC) exhibit reduced virulence potential.

    Science.gov (United States)

    Starcic Erjavec, Marjanca; Rijavec, Matija; Krizan-Hergouth, Veronika; Fruth, Angelika; Zgur-Bertok, Darja

    2007-11-01

    It is well documented that uropathogenic Escherichia coli (UPEC) isolates resistant to nalidixic acid have reduced virulence potential. Our goal was to assess whether UPEC isolates resistant to chloramphenicol, tetracycline and streptomycin also exhibit reduced virulence potential. Among 110 human UPEC isolates, the prevalences of the virulence factors fimH, papC, papGII, papGIII, sfa/focDE, afa, hlyA, cnf1, usp, ibeA, fyuA, iroN, iucD, ireA, and K1 and K5 capsules as well as of pathotypes, phylogenetic groups, O antigens and a pathogenicity island (PAI) marker were compared between chloramphenicol-, tetracycline-, streptomycin- and, as a control, nalidixic acid-resistant and -susceptible strains. Our findings show that among human UPEC isolates, not only nalidixic acid-resistant but also chloramphenicol- and tetracycline-resistant isolates have reduced virulence potential compared with susceptible strains. To our knowledge, this is the first report of a statistically significant reduction in virulence traits among chloramphenicol- and tetracycline-resistant isolates.

  6. Escherichia coli

    Science.gov (United States)

    Qian, Cunzhong; Hou, Jiafa

    2017-10-01

    The present study aimed to investigate whether Escherichia coli virulence affects the roles of sex hormone receptors in female dogs with simulated pyometra. A total of 33 healthy, nulliparous, crossbred female dogs were divided into four groups, with 10 dogs in each of the three experimental groups and 3 dogs in the control group. Estradiol was administrated to female dogs in group 1 continuously at 0.6-4.8 mg/kg twice daily for 12 days (the dose doubled every three days), followed by intramuscular injection of 0.2-1.8 mg/kg progesterone. The progesterone was administrated with an initial dose of 0.2 µg/kg and increased 0.2 mg/kg every three days, twice daily until the maximum of 1.8 mg/kg for 24 days and maintained at 1.8 mg/kg for 19 days. Progesterone only was administrated at 1.8 mg/kg in group 2 (twice daily) for 55 continuous days and only estradiol was administered with an initial dose of 0.6 µg/kg (dose doubled every 3 days for 12 days) in group 3 twice daily and maintained at 4.8 mg/kg for the following 43 days. A strongly virulent E. coli strain, nau-b, and a weakly virulent strain, nau-i, were screened. On the 12th day of diestrus, 5 female dogs in each of the experimental groups were inoculated with E. coli nau-i strain, while the other five in each group were inoculated with nau-b strain. Histopathological changes of uterine tissues were microscopically observed 50 days after E. coli inoculation and hormone receptor expression levels were detected by quantitative polymerase chain reaction. Simulated pyometra was observed in dogs administrated with progesterone alone or progesterone combined with estradiol. The clinical symptoms and histopathological observation demonstrated that inoculation with strongly virulent E. coli strain, nau-b, caused earlier onset of pyometra symptoms and more severe pyometra symptoms compared with the weakly virulent E. coli strain, nau-i. Furthermore, estrogen and progesterone receptor levels in dogs with pyometra

  7. Diet‐induced obese mice exhibit altered immune responses to acute lung injury induced by Escherichia coli

    Science.gov (United States)

    Wan, Taomei; Yuan, Guiqiang; Ren, Yi; Wang, Zhengyi; Jia, Yiping; Cui, Hengmin; Peng, Xi; Fang, Jing; Deng, Junliang; Yu, Shumin; Hu, Yanchun; Shen, Liuhong; Ma, Xiaoping; Wang, Ya; Ren, Zhihua

    2016-01-01

    Objective Obesity has been associated with impaired immunity and increased susceptibility to bacterial infection. It also exerts protective effects against mortality secondary to acute lung injury. The effects of obesity on immune responses to acute lung injury induced by Escherichia coli were investigated to determine if the above‐mentioned differences in its effects were related to infection severity. Methods Diet‐induced obesity (DIO) and lean control mice received intranasal instillations of 109 or 1010 CFUs of E. coli. The immune responses were examined at 0 h (uninfected), 24 h, and 96 h postinfection. Results Following infection, the DIO mice exhibited higher leukocyte, interleukin (IL)−10, IL‐6, and tumor necrosis factor‐α levels and more severe lung injury than the lean mice. Following inoculation with 1010 CFUs of E. coli, the DIO mice exhibited higher mortality and more severe inflammation‐induced injury than the lean mice, but no differences in E. coli counts were noted between the two groups. However, inoculated with 109 CFUs of E. coli, the DIO mice exhibited smaller E. coli burdens at 24 h and 96 h after infection, as well as lower concentrations of IL‐10 and tumor necrosis factor‐α and less severe lung injury at 96 h after infection. Conclusions The results support the emerging view that obesity may be beneficial in the setting of milder infection but detrimental in the setting of more severe infection. PMID:27558300

  8. Escherichia coli Braun Lipoprotein (BLP) exhibits endotoxemia - like pathology in Swiss albino mice.

    Science.gov (United States)

    Lakshmikanth, Chikkamenahalli Lakshminarayana; Jacob, Shancy Petsel; Kudva, Avinash Kundadka; Latchoumycandane, Calivarathan; Yashaswini, Puttaraju Srikanta Murthy; Sumanth, Mosale Seetharam; Goncalves-de-Albuquerque, Cassiano F; Silva, Adriana R; Singh, Sridevi Annapurna; Castro-Faria-Neto, Hugo C; Prabhu, Sandeep Kumble; McIntyre, Thomas M; Marathe, Gopal Kedihithlu

    2016-10-04

    The endotoxin lipopolysaccharide (LPS) promotes sepsis, but bacterial peptides also promote inflammation leading to sepsis. We found, intraperitoneal administration of live or heat inactivated E. coli JE5505 lacking the abundant outer membrane protein, Braun lipoprotein (BLP), was less toxic than E. coli DH5α possessing BLP in Swiss albino mice. Injection of BLP free of LPS purified from E. coli DH5α induced massive infiltration of leukocytes in lungs and liver. BLP activated human polymorphonuclear cells (PMNs) ex vivo to adhere to denatured collagen in serum and polymyxin B independent fashion, a property distinct from LPS. Both LPS and BLP stimulated the synthesis of platelet activating factor (PAF), a potent lipid mediator, in human PMNs. In mouse macrophage cell line, RAW264.7, while both BLP and LPS similarly upregulated TNF-α and IL-1β mRNA; BLP was more potent in inducing cyclooxygenase-2 (COX-2) mRNA and protein expression. Peritoneal macrophages from TLR2-/- mice significantly reduced the production of TNF-α in response to BLP in contrast to macrophages from wild type mice. We conclude, BLP acting through TLR2, is a potent inducer of inflammation with a response profile both common and distinct from LPS. Hence, BLP mediated pathway may also be considered as an effective target against sepsis.

  9. Escherichia coli Braun Lipoprotein (BLP) exhibits endotoxemia – like pathology in Swiss albino mice

    Science.gov (United States)

    Lakshmikanth, Chikkamenahalli Lakshminarayana; Jacob, Shancy Petsel; Kudva, Avinash Kundadka; Latchoumycandane, Calivarathan; Yashaswini, Puttaraju Srikanta Murthy; Sumanth, Mosale Seetharam; Goncalves-de-Albuquerque, Cassiano F.; Silva, Adriana R.; Singh, Sridevi Annapurna; Castro-Faria-Neto, Hugo C.; Prabhu, Sandeep Kumble; McIntyre, Thomas M.; Marathe, Gopal Kedihithlu

    2016-01-01

    The endotoxin lipopolysaccharide (LPS) promotes sepsis, but bacterial peptides also promote inflammation leading to sepsis. We found, intraperitoneal administration of live or heat inactivated E. coli JE5505 lacking the abundant outer membrane protein, Braun lipoprotein (BLP), was less toxic than E. coli DH5α possessing BLP in Swiss albino mice. Injection of BLP free of LPS purified from E. coli DH5α induced massive infiltration of leukocytes in lungs and liver. BLP activated human polymorphonuclear cells (PMNs) ex vivo to adhere to denatured collagen in serum and polymyxin B independent fashion, a property distinct from LPS. Both LPS and BLP stimulated the synthesis of platelet activating factor (PAF), a potent lipid mediator, in human PMNs. In mouse macrophage cell line, RAW264.7, while both BLP and LPS similarly upregulated TNF-α and IL-1β mRNA; BLP was more potent in inducing cyclooxygenase-2 (COX-2) mRNA and protein expression. Peritoneal macrophages from TLR2−/− mice significantly reduced the production of TNF-α in response to BLP in contrast to macrophages from wild type mice. We conclude, BLP acting through TLR2, is a potent inducer of inflammation with a response profile both common and distinct from LPS. Hence, BLP mediated pathway may also be considered as an effective target against sepsis. PMID:27698491

  10. Escherichia coli pathotypes

    Science.gov (United States)

    Escherichia coli strains are important commensals of the intestinal tract of humans and animals; however, pathogenic strains, including diarrhea-inducing E. coli and extraintestinal pathogenic E. coli. Intestinal E. coli pathotypes may cause a dehydrating watery diarrhea, or more severe diseases su...

  11. Escherichia coli Infections.

    Science.gov (United States)

    Makvana, Sejal; Krilov, Leonard R

    2015-04-01

    Virulent strains of Escherichia coli are responsible for most diarrheal infections, meningitis, septicemia, and urinary tract infections in children worldwide. Clinicians must learn to recognize, treat, and prevent these infections. After completing this article, readers should be able to: 1. Describe the epidemiology of E coli infections. 2. Recognize the clinical features of E coli infections, including the O157: H7 strain. 3. Appropriately treat children with various types of E coli infections. 4. Understand ways to prevent E coli infections.

  12. 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 ...

  13. Avian extraintestinal Escherichia coli exhibits enterotoxigenic-like activity in the in vivo rabbit ligated ileal loop assay.

    Science.gov (United States)

    Maluta, Renato Pariz; Gatti, Maria Silvia Viccari; Joazeiro, Paulo Pinto; de Paiva, Jacqueline Boldrin; Rojas, Thaís Cabrera Galvão; Silveira, Flávio; Houle, Sébastien; Kobayashi, Renata Katsuko Takayama; Dozois, Charles M; Dias da Silveira, Wanderley

    2014-06-01

    Avian pathogenic Escherichia coli (APEC) strains harbor a number of virulence genes and cause extraintestinal diseases, such as septicemia, swollen-head syndrome, salpingitis, and omphalitis in poultry. APEC strains are not known to cause intestinal diseases. Herein, for the first time, it is reported that APEC strains were able to induce an enterotoxigenic-like effect in rabbit ligated ileal loops. Strain SEPT362 caused cell detachment of the intestinal villi, which also showed a flattened and wilted appearance, but the integrity of the tight junctions was maintained. Additionally, this strain did not adhere to enterocytes in vivo, although adhesin encoding genes ( fimH, csgA, lpfA2-3, and ECP) were present while other lpfA types, sfa, afa, papC, and ral genes were not. This enterotoxigenic-like activity was conserved after thermal treatment of the supernatant at 65°C but not at 100°C. Moreover, experiments based on filtering with different molecular weight cut-off (MWCO) pore sizes demonstrated that the component associated with the observed biological effect has a molecular weight >100 kDa. Blast search and polymerase chain reaction assays for known E. coli virulence factors showed that strain SEPT362 harbors the gene encoding for the toxin EAST-1 and the serine protease autotransporter (SPATE) Tsh, but is negative for genes encoding for the toxins LT-I, STh, STp, Stx1, Stx2, CNF-1, CNF-2, CDT and the SPATEs Sat, Pic, Vat, SigA, SepA, EatA, EspP, or EspC. A cloned copy of the tsh gene in E. coli K-12 was also tested and was shown to have an enterotoxic effect. These results suggest that APEC might induce fluid accumulation in the rabbit gut. The Tsh autotransporter seems to be one of the factors associated with this phenotype.

  14. Diarrheagenic Escherichia coli.

    Science.gov (United States)

    Gomes, Tânia A T; Elias, Waldir P; Scaletsky, Isabel C A; Guth, Beatriz E C; Rodrigues, Juliana F; Piazza, Roxane M F; Ferreira, Luís C S; Martinez, Marina B

    2016-12-01

    Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  15. Escherichia coli exhibits a membrane-related response to a small arginine- and tryptophan-rich antimicrobial peptide.

    Science.gov (United States)

    Fränzel, Benjamin; Penkova, Maya; Frese, Christian; Metzler-Nolte, Nils; Andreas Wolters, Dirk

    2012-08-01

    Since multiresistant bacterial strains are more widespread and the victim numbers steadily increase, it is very important to possess a broad bandwidth of antimicrobial substances. Antibiotics often feature membrane-associated effect mechanisms. So, we present a membrane proteomic approach to shed light on the cellular response of Escherichia coli as model organism to the hexapeptide MP196, which is arginine and tryptophan rich. Analyzing integral membrane proteins are still challenging, although various detection strategies have been developed in the past. In particular, membrane proteomics in bacteria have been conducted very little due to the special physical properties of these membrane proteins. To obtain more information on the cellular response of the new compound group of small peptides, the tryptophan- and arginine-rich hexapeptide MP196 was subject to a comprehensive quantitative membrane proteomic study on E. coli by means of metabolic labeling in combination with membrane lipid analyses. This study provides in total 767 protein identifications including 185 integral membrane proteins, from which 624 could be quantified. Among these proteins, 134 were differentially expressed. Thereby, functional groups such as amino acid and membrane biosynthesis were affected, stress response could be observed, and the lipid composition of the membrane was significantly altered. Especially, the strong upregulation of the envelope stress induced protein. Spy indicates membrane damage, as well as the downregulation of the mechano-sensitive channel MscL beside others. Finally, the exceptional downregulation of transport systems strengthens these findings. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Recombinant Escherichia coli strains with inducible Campylobacter jejuni single domain hemoglobin CHb expression exhibited improved cell growth in bioreactor culture.

    Directory of Open Access Journals (Sweden)

    Li Xu

    Full Text Available Maintaining an appropriate concentration of dissolved oxygen in aqueous solution is critical for efficient operation of a bioreactor, requiring sophisticated engineering design and a system of regulation to maximize oxygen transfer from the injected air bubbles to the cells. Bacterial hemoglobins are oxygen-binding proteins that transfer oxygen from the environment to metabolic processes and allow bacteria to grow even under microaerophilic conditions. To improve the oxygen utilization efficiency of cells and overcome the oxygen shortage in bioreactors, the gene coding for the Campylobacter jejuni single domain hemoglobin (CHb gene was artificially synthesized and functionally expressed under the control of inducible expression promoters PT7 and Pvgh in Escherichia coli. The effects of the recombinants PT7-CHb and Pvgh-CHb on cell growth were evaluated in aerobic shake flasks, anaerobic capped bottles and a 5-L bioreactor, and a pronounced improvement in cell biomass was observed for CHb-expressing cells. To determine the growth curves, CHb gene expression, and CHb oxygen-binding capacity of specific recombinants with different promoters, we determined the time course of CHb gene expression in the two recombinants by semi-quantitative RT-PCR and CO differential spectrum assays. Based on the growth patterns of the two recombinants in the bioreactor, we proposed different recombinant types with optimal performance under specific culture conditions.

  17. Enterohemorrhagic Escherichia coli (EHEC

    Directory of Open Access Journals (Sweden)

    Abdullah Kilic

    2011-08-01

    Full Text Available Escherichia coli is a bacterium that is commonly found in the gut of humans and warm-blooded animals. Most strains of E. coli are harmless for human. E. coli O157:H7 is the most common member of a group of pathogenic E. coli strains known variously as enterohaemorrhagic, verocytotoxin-producing, or Shiga-toxin-producing organisms. EHEC bacterium is the major cause of haemorrhagic colitis and haemolytic uraemic syndrome. The reservoir of this pathogen appears to be mainly cattle and other ruminants such as camels. It is transmitted to humans primarily through consumption of contaminated foods. [TAF Prev Med Bull 2011; 10(4.000: 387-388

  18. PART I. ESCHERICHIA COLI

    Directory of Open Access Journals (Sweden)

    Sanaa Mahdi Oraibi

    2016-11-01

    Full Text Available The presence of Escherichia coli in the air of facilities involved in management and composting of post-slaughter poultry wastes in selected plants of West Western Pomerania region was studied. Measurements were made on four dates in a variety of weather conditions during the year. The study was conducted at 5 objects that differ in the type of waste and the degree of preparation for composting. These were: chemical treatment and preliminary processing plant, liquid wastes reservoir, platform for preparation of materials for composting, storage of biological sediments, and composting facility. Measurement of bacteria count was carried out in accordance with the applicable procedures on selective chromogenic TBX medium. The assays revealed the presence of E. coli at all test objects, but not always on all measurement dates. It has been shown that the presence of E. coli was from 20 to 3047 CFU∙m-3 of air, although the largest quantities were most frequently detected in the air of the building for post-slaughter waste pre-treatment in chemical treatment plant.

  19. ANIMAL ENTEROTOXIGENIC ESCHERICHIA COLI

    Science.gov (United States)

    Dubreuil, J. Daniel; Isaacson, Richard E.; Schifferli, Dieter M.

    2016-01-01

    Enterotoxigenic Escherichia coli (ETEC) is the most common cause of E. coli diarrhea in farm animals. ETEC are characterized by the ability to produce two types of virulence factors; adhesins that promote binding to specific enterocyte receptors for intestinal colonization and enterotoxins responsible for fluid secretion. The best-characterized adhesins are expressed in the context of fimbriae, such as the F4 (also designated K88), F5 (K99), F6 (987P), F17 and F18 fimbriae. Once established in the animal small intestine, ETEC produces enterotoxin(s) that lead to diarrhea. The enterotoxins belong to two major classes; heat-labile toxin that consist of one active and five binding subunits (LT), and heat-stable toxins that are small polypeptides (STa, STb, and EAST1). This chapter describes the disease and pathogenesis of animal ETEC, the corresponding virulence genes and protein products of these bacteria, their regulation and targets in animal hosts, as well as mechanisms of action. Furthermore, vaccines, inhibitors, probiotics and the identification of potential new targets identified by genomics are presented in the context of animal ETEC. PMID:27735786

  20. 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...

  1. Investigation of ’Escherichia coli’ Enterotoxins

    Science.gov (United States)

    1978-05-01

    creases substantially when certain strains of E. coli are grown in the presence of the antibiotic, chloramphenicol (10). Using the skin test to assay for...8. antigens. Somewhat unexpectedly, it was observed that the combined ant- igens exhibited synergism : when administered together, they elicited...Escherichia coli in the presence of chloramphenicol . J. Bacteriol. 110:667-676, (continued) 12. 11. Levner, M.H., Wiener, F.P., Rubin, B.A. Induction of

  2. PATHOGENIC POTENTIALS OF ESCHERICHIA COLI

    African Journals Online (AJOL)

    Electrolyte and haematological parameters in rabbits infected with pathogenic isolates of Escherichia coli from rural water supplies ... rabbits not infected with E. coli. ..... Basic pathology. 4lh ed. ' ' Saunders W.B Company London. Ppl75. Tillman, S.M.M.C. Conover and AG. Tilkian. 1979. Blood Chemistry Electrolytes. In:.

  3. Distinct Transcriptional Profiles and Phenotypes Exhibited by Escherichia coli O157:H7 Isolates Related to the 2006 Spinach-Associated Outbreak

    OpenAIRE

    Parker, Craig T.; Kyle, Jennifer L.; Huynh, Steven; Carter, Michelle Q.; Brandl, Maria T.; Mandrell, Robert E.

    2012-01-01

    In 2006, a large outbreak of Escherichia coli O157:H7 was linked to the consumption of ready-to-eat bagged baby spinach in the United States. The likely sources of preharvest spinach contamination were soil and water that became contaminated via cattle or feral pigs in the proximity of the spinach fields. In this study, we compared the transcriptional profiles of 12 E. coli O157:H7 isolates that possess the same two-enzyme pulsed-field gel electrophoresis (PFGE) profile and are related tempor...

  4. 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...

  5. Synergistic effects in mixed Escherichia coli biofilms

    DEFF Research Database (Denmark)

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

    2006-01-01

    the 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 of conjugation genes...

  6. 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...

  7. Conjugal Pairing in Escherichia Coli

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 8. Conjugal Pairing in Escherichia Coli. Joshua Lederberg. Classics Volume 13 Issue 8 August 2008 pp 793-794. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/013/08/0793-0794 ...

  8. Distinct transcriptional profiles and phenotypes exhibited by Escherichia coli O157:H7 isolates related to the 2006 spinach-associated outbreak.

    Science.gov (United States)

    Parker, Craig T; Kyle, Jennifer L; Huynh, Steven; Carter, Michelle Q; Brandl, Maria T; Mandrell, Robert E

    2012-01-01

    In 2006, a large outbreak of Escherichia coli O157:H7 was linked to the consumption of ready-to-eat bagged baby spinach in the United States. The likely sources of preharvest spinach contamination were soil and water that became contaminated via cattle or feral pigs in the proximity of the spinach fields. In this study, we compared the transcriptional profiles of 12 E. coli O157:H7 isolates that possess the same two-enzyme pulsed-field gel electrophoresis (PFGE) profile and are related temporally or geographically to the above outbreak. These E. coli O157:H7 isolates included three clinical isolates, five isolates from separate bags of spinach, and single isolates from pasture soil, river water, cow feces, and a feral pig. The three clinical isolates and two spinach bag isolates grown in cultures to stationary phase showed decreased expression of many σ(S)-regulated genes, including gadA, osmE, osmY, and katE, compared with the soil, water, cow, feral pig, and the other three spinach bag isolates. The decreased expression of these σ(S)-regulated genes was correlated with the decreased resistance of the isolates to acid stress, osmotic stress, and oxidative stress but increases in scavenging ability. We also observed that intraisolate variability was much more pronounced among the clinical and spinach isolates than among the environmental isolates. Together, the transcriptional and phenotypic differences of the spinach outbreak isolates of E. coli O157:H7 support the hypothesis that some variants within the spinach bag retained characteristics of the preharvest isolates, whereas other variants with altered gene expression and phenotypes infected the human host.

  9. Chitinase Genes LbCHI31 and LbCHI32 from Limonium bicolor Were Successfully Expressed in Escherichia coli and Exhibit Recombinant Chitinase Activities

    Science.gov (United States)

    Liu, Zhihua; Huang, Ying; Zhang, Rongshu; Diao, Guiping; Fan, Haijuan; Wang, Zhiying

    2013-01-01

    The two chitinase genes, LbCHI31 and LbCHI32 from Limonium bicolor, were, respectively, expressed in Escherichia coli BL21 strain. The intracellular recombinant chitinases, inrCHI31 and inrCHI32, and the extracellular exrCHI31 and exrCHI32 could be produced into E. coli. The exrCHI31 and exrCHI32 can be secreted into extracellular medium. The optimal reaction condition for inrCHI31 was 5 mmol/L of Mn2+ at 40°C and pH 5.0 with an activity of 0.772 U using Alternaria alternata cell wall as substrate. The optimal condition of inrCHI32 was 5 mmol/L of Ba2+ at 45°C and pH 5.0 with an activity of 0.792 U using Valsa sordida cell wall as substrate. The optimal reaction condition of exrCHI31 was 5 mmol/L of Zn2+ at 40°C and pH 5.0, and the activity was 0.921 U using the A. alternata cell wall as substrate. Simultaneously, the optimal condition of exrCHI32 was 5 mmol/L of K+ at 45°C and pH 5.0, with V. sordida cell wall as the substrate, and the activity was 0.897 U. Furthermore, the activities of extracellular recombinant enzymes on fungal cell walls and compounds were generally higher than those of the intracellular recombinant enzymes. Recombinant exrCHI31 and exrCHI32 have better hydrolytic ability on cell walls of different fungi than synthetic chitins and obviously showed activity against A. alternata. PMID:24385885

  10. Escherichia coli bactofection using Lipofectamine.

    Science.gov (United States)

    Narayanan, Kumaran; Lee, Choon Weng; Radu, Aurelian; Sim, Edmund Ui Hang

    2013-08-15

    Successful gene delivery into mammalian cells using bactofection requires entry of the bacterial vector via cell surface integrin receptors followed by release of plasmid DNA into the cellular environment. We show, for the first time, that addition of the DNA transfection reagent Lipofectamine improves entry of invasive Escherichia coli into HeLa cells and enhances up to 2.8-fold green fluorescent protein (GFP) expression from a reporter plasmid. The addition of Lipofectamine may be applicable to other bacterial vectors to increase their DNA delivery efficiency into mammalian cells. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. PATHOGENIC POTENTIALS OF ESCHERICHIA COLI ISOLATED ...

    African Journals Online (AJOL)

    Electrolyte and haematological parameters in rabbits infected with pathogenic isolates of Escherichia coli from rural water supplies in Rivers State, Nigeria, where monitored. Rabbits were orally infected with suspension containing 3x107 cfu /ml of Escherichia coli to induce diarrhoea, and the electrolyte (sodium, potassium ...

  12. Enteroaggregative Escherichia coli in Daycare

    DEFF Research Database (Denmark)

    Hebbelstrup Jensen, Betina; Stensvold, Christen R.; Struve, Carsten

    2016-01-01

    Enteroaggregative Escherichia coli (EAEC) has been associated with persistent diarrhea, reduced growth acceleration, and failure to thrive in children living in developing countries and with childhood diarrhea in general in industrialized countries. The clinical implications of an EAEC carrier-st...... heterogeneity of this pathotype. EAEC was highly prevalent (n = 25, 14%) in Danish children in daycare centers and was accompanied by gastrointestinal symptoms in 56% of the infected children. No serotype or phylogenetic group was specifically linked to children with disease....... and 2013. This is the first investigation of the incidence and pathological significance of EAEC in Danish children attending daycare facilities. Conventional microbiological detection of enteric pathogens was performed at Statens Serum Institute, Copenhagen, Denmark, and at Hvidovre Hospital, Copenhagen...

  13. Peptidoglycan Hydrolases of Escherichia coli

    Science.gov (United States)

    van Heijenoort, Jean

    2011-01-01

    Summary: The review summarizes the abundant information on the 35 identified peptidoglycan (PG) hydrolases of Escherichia coli classified into 12 distinct families, including mainly glycosidases, peptidases, and amidases. An attempt is also made to critically assess their functions in PG maturation, turnover, elongation, septation, and recycling as well as in cell autolysis. There is at least one hydrolytic activity for each bond linking PG components, and most hydrolase genes were identified. Few hydrolases appear to be individually essential. The crystal structures and reaction mechanisms of certain hydrolases having defined functions were investigated. However, our knowledge of the biochemical properties of most hydrolases still remains fragmentary, and that of their cellular functions remains elusive. Owing to redundancy, PG hydrolases far outnumber the enzymes of PG biosynthesis. The presence of the two sets of enzymes acting on the PG bonds raises the question of their functional correlations. It is difficult to understand why E. coli keeps such a large set of PG hydrolases. The subtle differences in substrate specificities between the isoenzymes of each family certainly reflect a variety of as-yet-unidentified physiological functions. Their study will be a far more difficult challenge than that of the steps of the PG biosynthesis pathway. PMID:22126997

  14. Avian pathogenic Escherichia coli (APEC).

    Science.gov (United States)

    Dho-Moulin, M; Fairbrother, J M

    1999-01-01

    Avian pathogenic Escherichia coli (APEC) cause aerosacculitis, polyserositis, septicemia and other mainly extraintestinal diseases in chickens, turkeys and other avian species. APEC are found in the intestinal microflora of healthy birds and most of the diseases associated with them are secondary to environmental and host predisposing factors. APEC isolates commonly belong to certain serogroups, O1, O2 and O78, and to a restricted number of clones. Several experimental models have been developed, permitting a more reliable evaluation of the pathogenicity of E. coli for chickens and turkeys. Hence, virulence factors identified on APEC are adhesins such as the F1 and P fimbriae, and curli, the aerobactin iron sequestering system, K1 capsule, temperature-sensitive hemagglutinin (Tsh), resistance to the bactericidal effects of serum and cytotoxic effects. Experimental infection studies have shown that the air-exchange regions of the lung and the airsacs are important sites of entry of E. coli into the bloodstream of birds during the initial stages of infection and that resistance to phagocytosis may be an important mechanism in the development of the disease. They have also demonstrated that F1 fimbriae are expressed in the respiratory tract, whereas P fimbriae are expressed in the internal organs of infected chickens. The role of these fimbrial adhesins in the development of disease is not yet, however, fully understood. The more recent use of genetic approaches for the identification of new virulence factors will greatly enhance our knowledge of APEC pathogenic mechanisms. Diagnosis of APEC infections is based on the clinical picture, lesions and isolation of E. coli. This may be strengthened by serotyping and identification of virulence factors using immunological or molecular methods such as DNA probes and PCR. Approaches for the prevention and control of APEC infections include the control of environmental contamination and environmental parameters such as

  15. Antimicrobial resistance among commensal Escherichia coli from ...

    African Journals Online (AJOL)

    user1

    2012-07-19

    Jul 19, 2012 ... This study monitored antimicrobial resistance in commensal Escherichia coli from the faeces of on-farm .... sterile tryptic soy broth (TSB) (Oxoid, Basingstoke, UK) in universal bottles. 10 g of ... Figure 1. Rates of antimicrobial resistance in E. coli isolates from the faeces of cattle and beef in Ibadan, Nigeria.

  16. escherichia coli serotypes confirmed in experimental mammary ...

    African Journals Online (AJOL)

    DJFLEX

    SEROTYPES CONFIRMED IN EXPERIMENTAL MAMMARY GLAND. INFECTIONS. P. A. AKPAN AND ... 037, 02a and 109) in mammary glands of experimental cows (cow 105, 107 and 102 respectively). Pathogenicity of the E. coli which ..... Akpan, P. A and Ikpeme, E. U., 2005. pathology of. Experimental Escherichia Coli ...

  17. Prevalence of Escherichia coli O157

    NARCIS (Netherlands)

    Abdissa, Rosa; Haile, Woynshet; Fite, Akafete Teklu; Beyi, Ashenafi Feyisa; Agga, Getahun E.; Edao, Bedaso Mammo; Tadesse, Fanos; Korsa, Mesula Geloye; Beyene, Takele; Beyene, Tariku Jibat; Zutter, De Lieven; Cox, Eric; Goddeeris, Bruno Maria

    2017-01-01

    Background: There is paucity of information regarding the epidemiology of Escherichia coli O157: H7 in developing countries. In this study, we investigated the occurrence of E. coli O157: H7 associated with beef cattle at processing plants and at retail shops in Ethiopia. Methods: Various samples

  18. Genes under positive selection in Escherichia coli

    DEFF Research Database (Denmark)

    Petersen, Lise; Bollback, Jonathan P; Dimmic, Matt

    2007-01-01

    We used a comparative genomics approach to identify genes that are under positive selection in six strains of Escherichia coli and Shigella flexneri, including five strains that are human pathogens. We find that positive selection targets a wide range of different functions in the E. coli genome...

  19. Characterization of Escherichia coli Phylogenetic Groups ...

    African Journals Online (AJOL)

    Background: Escherichia coli strains mainly fall into four phylogenetic groups (A, B1, B2, and D) and that virulent extra‑intestinal strains mainly belong to groups B2 and D. Aim: The aim was to determine the association between phylogenetic groups of E. coli causing extraintestinal infections (ExPEC) regarding the site of ...

  20. 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...

  1. Escherichia coli survival in waters: Temperature dependence

    Science.gov (United States)

    Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q10 mo...

  2. ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli

    OpenAIRE

    ANGGREINI, RAHAYU

    2015-01-01

    2015 RAHAYU ANGGREINI coli Penelitian ini bertujuan untuk melakukan identifikasi cemaran bakteri E. coli O157:H7 pada daging sapi di kota Makassar. Sampel pada penelitian ini sebanyak 72 sampel Kata Kunci : Daging sapi, pasar tradisional, E. coli, E. coli O157:H7, kontaminasi bakteri, identifikasi E. coli O157:H7.

  3. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Escherichia coli serological reagents. 866.3255... coli serological reagents. (a) Identification. Escherichia coli serological reagents are devices that consist of antigens and antisera used in serological tests to identify Escherichia coli from cultured...

  4. [Avian pathogenic Escherichia coli (APEC)].

    Science.gov (United States)

    Ewers, Christa; Janssen, Traute; Wieler, Lothar H

    2003-01-01

    Infections with avian pathogenic Escherichia coli (APEC) cause colibacillosis, an acute and mostly systemic disease resulting in significant economic losses in poultry industry worldwide. Avian colibacillosis is a complex syndrome characterized by multiple organ lesions with airsacculitis and associated pericarditis, perihepatitis and peritonitis being most typical. Environmental factors as well as the constitution of poultry or initial viral infections influence the outcome of APEC-infections. However, several challenge experiments in chickens proofed the role of virulent APEC strains as the single aetiological agent. Currently serotypes O1:K1, O2:K1 and O78:K80 are recognized as the most prevalent, however the number of published serotypes is increasing. In addition, single APEC isolates vary profoundly in virulence, and knowledge about the molecular basis of this variability is still scarce. Known virulence factors of APEC are adhesins (F1- and P-fimbriae), iron acquisition systems (aerobactin and yersiniabactin), hemolysins (hemolysinE and temperaturesensitive hemagglutinin), resistance to the bactericidal effects of serum and phagocytosis (outer membrane protein, iss protein, lipopolysaccharide, K/1)-capsule and colilcin production) as well as toxins and cytotoxins (heat stable toxin, cyto-/verotoxin and flagella toxin). Esperimental studies have shown that the respiratory tract, principally the gas-exchange region of the lung and the interstitium of the air sacs are the most important sites of entry for avian pathogenic E. coli. APEC strains adhere to the epithelial cells of air sacs presumably through F1-fimbriae. After colonization and multiplication the bacteria enter the bloodstream, and the temperature-sensitive hemagglutinin (tsh) seems to be important int his step. After invading the bloodstream APEC cause a septicemia resulting in massive lesins in multiple internal organs and in sudden death of the birds. The ability of the bacteria to acquire iron

  5. Escherichia coli fimbriae recognizing sialyl galactosides.

    OpenAIRE

    Korhonen, T K; Väisänen-Rhen, V; Rhen, M; Pere, A; Parkkinen, J; Finne, J

    1984-01-01

    Fimbriae recognizing sialyl galactosides (S fimbriae) were purified from an Escherichia coli strain. The S fimbriae were morphologically identical to type 1 and P fimbriae of E. coli and showed a hemagglutination that was abolished when erythrocytes were treated with neuraminidase. Hemagglutination by the purified fimbriae was inhibited by orosomucoid but not by its desialylated derivative. Of the oligosaccharides tested, sialyl-(alpha 2-3)-lactose and sialyl-(alpha 2-3)-N-acetyllactosamine h...

  6. Native valve Escherichia coli endocarditis following urosepsis

    Directory of Open Access Journals (Sweden)

    D Rangarajan

    2013-01-01

    Full Text Available 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.

  7. Native valve Escherichia coli endocarditis following urosepsis

    OpenAIRE

    Rangarajan, D.; Ramakrishnan, S.; Patro, K. C.; Devaraj, S.; Krishnamurthy, V.; 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. 77 FR 9888 - Shiga Toxin-Producing Escherichia coli

    Science.gov (United States)

    2012-02-21

    ... Food Safety and Inspection Service Shiga Toxin-Producing Escherichia coli in Certain Raw Beef Products... manufacturing trimmings for six non-O157 Shiga toxin-producing Escherichia coli (STEC) serogroups (O26, O45..., non-intact product, that are contaminated with Shiga toxin-producing Escherichia coli (STEC) O26, O45...

  9. Cell Shape Dynamics in Escherichia coli

    OpenAIRE

    Reshes, Galina; Vanounou, Sharon; Fishov, Itzhak; Feingold, Mario

    2007-01-01

    Bacteria are the simplest living organisms. In particular, Escherichia coli has been extensively studied and it has become one of the standard model systems in microbiology. However, optical microscopy studies of single E. coli have been limited by its small size, ∼1 × 3 μm, not much larger than the optical resolution, ∼0.25 μm. As a result, not enough quantitative dynamical information on the life cycle of single E. coli is presently available. We suggest that, by careful analysis of images ...

  10. Whole Genome Epidemiological Typing of Escherichia coli

    OpenAIRE

    Kaas, Rolf Sommer; Aarestrup, Frank Møller; Ussery, David; Lund, Ole

    2014-01-01

    Escherichia coli (E. coli) spiller en vigtig rolle i den globale sundhed både grundet dennes rolle som kommensal bakterie, der lever i dennes vært og som patogen bakterie, der er skyld i millioner af infektioner hvert eneste år. Infektionerne er både sporadiske eller som udbrud med tusindvis af smittede i visse tilfælde. For at mindske antallet af infektioner er det vigtigt at overvåge patogene E. coli med henblik på hurtigt opdagelse af udbrud og sporing af kilden til disse. Effektiviteten a...

  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. Antibiotic resistance properties of uropathogenic Escherichia coli ...

    African Journals Online (AJOL)

    Purpose: To investigate the antibiotic resistance pattern of uropathogenic Escherichia coli (UPEC) ... UPEC strains showed the highest levels of resistance ... These changes, along with an already short urethra and difficulty with hygiene due to a distended pregnant belly, increase the frequency of urinary tract infections.

  13. Escherichia Coli Removal from Water Using Electrophotocatalytic ...

    African Journals Online (AJOL)

    Optimal removal (MPN: 0) was obtained at pH 8, time of electrolysis: 5 minutes, 2 layer of nano ZnO, and voltage of 10 V. This result offers that this method is an efficient method for water disinfection. @JASEM Keywords: Escherichia Coli , Water disinfection, Electrophotocatalytic, UV- A J. Appl. Sci. Environ. Manage. Sept ...

  14. lactamase in clinical isolates of Escherichia coli

    African Journals Online (AJOL)

    Jane

    2011-08-22

    Aug 22, 2011 ... ... Kolayli F, Karadenizli A, Demirdag K, Gunaydin. M, Altindis M, Caylan R, Ucmak H (2007) .Extended-spectrum beta- lactamases in ceftazidime resistant Escherichia coli and Klebsiella pneumoniae isolates in Turkish hospitals. Indian. J. Med. Microbiol. 25(4):346-350. Mammeri H, Gilly L, Laurans G,Vedel ...

  15. antimicrobial susceptibility and plasmids from escherichia coli

    African Journals Online (AJOL)

    2001-10-02

    Oct 2, 2001 ... 78 No. IO October 200]. ANTIMICROBIAL SUSCEPTIBILITY AND PLASMIDS FROM ESCHERICHIA COLI ISOLATED FROM RATS. FM. Gakuya, BVM, MSc, Field Veterinarian, Kenya Wildlife Services, M.N. Kyule, BVM, ... Request for reprints to: Dr FM. ... profile index (API) 20E strips (Bio Merieux, Marcy~l?

  16. Optimization of plasmid electrotransformation into Escherichia coli ...

    African Journals Online (AJOL)

    Application of statistical methods to determine the appropriate processes have been suggested for genetic engineering and biotechnology technique such as electroporation. This study explains the use of Taguchi statistical method to optimize the conditions for efficient plasmid transformation into Escherichia coli via ...

  17. Inhibition of Escherichia Coli, Salmonella and Staphylococcus ...

    African Journals Online (AJOL)

    Escherichia coli O157:H7, Salmonella typhimurium and Staphylococcus. aureus are of great concern to the food industry, especially in foods stored under refrigerated conditions where, unlike most food-borne pathogens are able to multiply. This investigation was conducted to study the inhibitory effect of some spice ...

  18. Antimicrobial Resistance in Escherichia Coli, Klebsiella ...

    African Journals Online (AJOL)

    Antimicrobial Resistance in Escherichia Coli, Klebsiella pneumoniae and Pseudomonas Aeruginosa Isolated from Milk of Dairy Cows in Three Nigerian Cities. ... The results demonstrated wide variation of in the susceptibility patterns for the various organisms from different regions of Nigeria. The three organisms displayed ...

  19. Compaction of isolated Escherichia coli nucleoids

    NARCIS (Netherlands)

    Wegner, Anna S.; Wintraecken, Kathelijne; Spurio, Roberto; Woldringh, Conrad L.; Vries, de Renko; Odijk, Theo

    2016-01-01

    Escherichia coli nucleoids were compacted by the inert polymer polyethylene glycol (PEG) in the presence of the H-NS protein. The protein by itself appears to have little impact on the size of the nucleoids as determined by fluorescent microscopy. However, it has a significant impact on the

  20. Tuning Escherichia coli for membrane protein overexpression

    NARCIS (Netherlands)

    Wagner, Samuel; Klepsch, Mirjam M.; Schlegel, Susan; Appel, Ansgar; Draheim, Roger; Tarry, Michael; Hogbom, Martin; van Wijk, Klaas J.; Slotboom, Dirk J.; Persson, Jan O.; de Gier, Jan-Willem; Högbom, Martin

    2008-01-01

    A simple generic method for optimizing membrane protein overexpression in Escherichia coli is still lacking. We have studied the physiological response of the widely used "Walker strains" C41(DE3) and C43(DE3), which are derived from BL21(DE3), to membrane protein overexpression. For unknown

  1. Biosensors for the detection of Escherichia coli

    African Journals Online (AJOL)

    Although Escherichia coli is still considered the best indicator of water quality, cell numbers may be below detection limits, or the cells may ..... ring between chemical reactions (chemical energy) and trans- duce these changes into .... dissolved oxygen and produce hydrogen peroxide (De Corcuera and Cavalieri, 2010) in a ...

  2. Antibiotic resistance properties of uropathogenic Escherichia coli ...

    African Journals Online (AJOL)

    Antibiotic resistance properties of uropathogenic Escherichia coli isolated from pregnant women with history of recurrent urinary tract infections. ... of infected pregnant women with imipenem, mezlocillin and nitrofurantoin would be effective for the prevention and management of vaginal infections in pregnant women.

  3. 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.…

  4. (ESBL) producing Escherichia coli and Klebsiella pneumoniae

    African Journals Online (AJOL)

    Emerging antibiotic resistance due to extended spectrum β-lactamase (ESBL) production limited the use of β-lactam antibiotics against Escherichia coli and Klebsiella pneumoniae. This observational study was conducted at the Microbiology department of the Children's Hospital, Lahore Pakistan, from June, 2009 to ...

  5. escherichia coli, klebsiella pneumoniae and proteus vulgaris

    African Journals Online (AJOL)

    DR. AMINU

    2010-06-01

    Jun 1, 2010 ... ABSTRACT. Psidium guajava (L.) leaves powder was extracted with ethanol and methanol using percolation method. The extracts were tested for antimicrobial activity against clinical isolates of confirmed extended spectrum β-lactamase producing Escherichia coli, Klebsiella pneumoniae and Proteus.

  6. Shiga toxin-producing Escherichia coli

    DEFF Research Database (Denmark)

    Pedersen, Rune Micha; Nielsen, Marc Trunjer Kusk; Möller, Sören

    2018-01-01

    OBJECTIVES: Shiga toxin-producing Escherichia coli (STEC) causes diarrhoeal disease, bloody diarrhoea and haemolytic uraemic syndrome. The aim of this study was to describe the incidence of STEC and the clinical features of STEC patients from a well-defined Danish population in which all fecal...

  7. Multiplex Genome Editing in Escherichia coli

    DEFF Research Database (Denmark)

    Ingemann Jensen, Sheila; Nielsen, Alex Toftgaard

    2018-01-01

    Lambda Red recombineering is an easy and efficient method for generating genetic modifications in Escherichia coli. For gene deletions, lambda Red recombineering is combined with the use of selectable markers, which are removed through the action of, e.g., flippase (Flp) recombinase. This PCR...

  8. 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...

  9. 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...

  10. 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....

  11. Emergence of Quinolone Resistance amongst Escherichia coli ...

    African Journals Online (AJOL)

    Two hundred and seventy three isolates of Escherichia coli obtained from 7 hospitals in Lagos were screened for Fluoroquinolone resistance (FQR). Rate of resistance was 22.3% showing an increase in quinolone resistance when compared with resistant rates between 1994 and 1999 which ranged from 0 – 2% then.

  12. Whole Genome Epidemiological Typing of Escherichia coli

    DEFF Research Database (Denmark)

    Kaas, Rolf Sommer

    Escherichia coli (E. coli) is of huge importance in global health both as a commensal organism living within its host or as a pathogen causing millions of infections each year. Infections occur both sporadic and as outbreaks with sometimes up to thousands of infected people. To limit the number...... of infections it is important to monitor pathogenic E. coli in order to detect outbreaks as quickly as possible and find the source of the outbreak. The effectiveness of monitoring and tracking of pathogens is very dependent on the typing methods that are employed. Classical typing methods employed for E. coli......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...

  13. Escherichia coli and Sudden Infant Death Syndrome.

    Science.gov (United States)

    Bettelheim, Karl A; Goldwater, Paul N

    2015-01-01

    This review examines the association of strains of Escherichia coli with sudden infant death syndrome (SIDS) and the possible role these bacteria play in this enigmatic condition. The review addresses evidence for E. coli in SIDS infants, potential sources of E. coli in the environment, colonization by commensal and pathogenic strains, the variety of currently accepted pathotypes, and how these pathotypes could compromise intestinal integrity and induce inflammation. Both intestinal and extraintestinal pathotypes are compared in relation to the apparent liability in which virulence traits can be gained or lost by strains of E. coli. The way in which E. coli infections fit with current views on infant sleeping position and other SIDS risk factors is highlighted.

  14. Escherichia coli and Sudden Infant Death Syndrome

    Directory of Open Access Journals (Sweden)

    Paul Nathan Goldwater

    2015-07-01

    Full Text Available This review examines the association of strains of Escherichia coli with Sudden Infant Death Syndrome (SIDS and the possible role of these bacteria play in this enigmatic condition. The review addresses evidence for E. coli in SIDS infants, potential sources of E. coli in the environment, colonisation by commensal and pathogenic strains, the variety of currently accepted pathotypes, and how these pathotypes could compromise intestinal integrity and induce inflammation. Both intestinal and extraintestinal pathotypes are compared in relation to the apparent lability in which virulence traits can be gained or lost by strains of E. coli. The way in which E. coli infections fit with current views on infant sleeping position and other SIDS risk factors is highlighted.

  15. 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.

  16. Oligosaccharide Binding in Escherichia coli Glycogen Synthase

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Fang; Yep, Alejandra; Feng, Lei; Preiss, Jack; Geiger, James H.; (MSU)

    2010-11-17

    Glycogen/starch synthase elongates glucan chains and is the key enzyme in the synthesis of glycogen in bacteria and starch in plants. Cocrystallization of Escherichia coli wild-type glycogen synthase (GS) with substrate ADPGlc and the glucan acceptor mimic HEPPSO produced a closed form of GS and suggests that domain-domain closure accompanies glycogen synthesis. Cocrystallization of the inactive GS mutant E377A with substrate ADPGlc and oligosaccharide results in the first oligosaccharide-bound glycogen synthase structure. Four bound oligosaccharides are observed, one in the interdomain cleft (G6a) and three on the N-terminal domain surface (G6b, G6c, and G6d). Extending from the center of the enzyme to the interdomain cleft opening, G6a mostly interacts with the highly conserved N-terminal domain residues lining the cleft of GS. The surface-bound oligosaccharides G6c and G6d have less interaction with enzyme and exhibit a more curled, helixlike structural arrangement. The observation that oligosaccharides bind only to the N-terminal domain of GS suggests that glycogen in vivo probably binds to only one side of the enzyme to ensure unencumbered interdomain movement, which is required for efficient, continuous glucan-chain synthesis.

  17. Infektionen mit darmpathogenen Escherichia coli.

    NARCIS (Netherlands)

    Friedrich, Alexander; Stein, Jürgen; Dignass, Axel

    2001-01-01

    E. coli ist ein wesentlicher Bestandteil der physiologischen Darmflora des Menschen. Die üblicherweise im Darm vorkommenden Kolibakterien sind apathogen und für den Menschen eher nützlich (Sonnenborn u. Greinwald 1990). Allerdings kennen wir bei dieser Bakterienspezies auch ein breites Spektrum von

  18. Robust Growth of Escherichia coli

    National Research Council Canada - National Science Library

    Wang, Ping; Robert, Lydia; Pelletier, James; Dang, Wei Lien; Taddei, Francois; Wright, Andrew; Jun, Suckjoon

    2010-01-01

    ... 1 A). We measured the timescale of nutrient uptake by E. coli by using the fluorescent glucose analog (2-NBDG) and found that diffusion into the channels is much faster (∼1 s) than the timescale of nutrient uptake (∼2–3 min; Supplemental Experimental Procedures , available online), ensuring steady-state conditions for all cells. The cell at...

  19. Infectious endocarditis caused by Escherichia coli

    DEFF Research Database (Denmark)

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

    2011-01-01

    -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......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...

  20. FTIR nanobiosensors for Escherichia coli detection

    Directory of Open Access Journals (Sweden)

    Stefania Mura

    2012-07-01

    Full Text Available Infections due to enterohaemorrhagic E. coli (Escherichia coli have a low incidence but can have severe and sometimes fatal health consequences, and thus represent some of the most serious diseases due to the contamination of water and food. New, fast and simple devices that monitor these pathogens are necessary to improve the safety of our food supply chain. In this work we report on mesoporous titania thin-film substrates as sensors to detect E. coli O157:H7. Titania films treated with APTES ((3-aminopropyltriethoxysilane and GA (glutaraldehyde were functionalized with specific antibodies and the absorption properties monitored. The film-based biosensors showed a detection limit for E. coli of 1 × 102 CFU/mL, constituting a simple and selective method for the effective screening of water samples.

  1. FTIR nanobiosensors for Escherichia coli detection

    Science.gov (United States)

    Greppi, Gianfranco; Marongiu, Maria Laura; Roggero, Pier Paolo; Ravindranath, Sandeep P; Mauer, Lisa J; Schibeci, Nicoletta; Perria, Francesco; Piccinini, Massimo; Innocenzi, Plinio; Irudayaraj, Joseph

    2012-01-01

    Summary Infections due to enterohaemorrhagic E. coli (Escherichia coli) have a low incidence but can have severe and sometimes fatal health consequences, and thus represent some of the most serious diseases due to the contamination of water and food. New, fast and simple devices that monitor these pathogens are necessary to improve the safety of our food supply chain. In this work we report on mesoporous titania thin-film substrates as sensors to detect E. coli O157:H7. Titania films treated with APTES ((3-aminopropyl)triethoxysilane) and GA (glutaraldehyde) were functionalized with specific antibodies and the absorption properties monitored. The film-based biosensors showed a detection limit for E. coli of 1 × 102 CFU/mL, constituting a simple and selective method for the effective screening of water samples. PMID:23019542

  2. Infectious endocarditis caused by Escherichia coli.

    Science.gov (United States)

    Lauridsen, Trine Kiilerich; Arpi, Magnus; Fritz-Hansen, Thomas; Frimodt-Møller, Niels; Bruun, Niels Eske

    2011-07-01

    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 for the correct diagnosis and treatment.

  3. 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...

  4. Hydrogen production by recombinant Escherichia coli strains

    Science.gov (United States)

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

    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 increasing hydrogen production are outlined and whole‐cell systems and cell‐free systems are compared. PMID:21895995

  5. Intestinal Colonization by Enterotoxigenic Escherichia coli.

    Science.gov (United States)

    1980-09-01

    piotective antigens for the development of vaccines to protect by active immunization . I’ DD I Fr 1473 EDITION OF NOV 65IS 0O’.OL ET K ( / / SECURITY...enterotoxin immunity presented by the existence of non-antigenic heat-stable types of enterotoxin. Preliminary efforts to protect by oral vaccination...SUMHARY -. Pregnant gilts were vaccinated orally with Escherichia coli that S- produce pilus antigens K99 or 987P. The vaccines were live or dead

  6. Gene encoding virulence markers among Escherichia coli isolates ...

    African Journals Online (AJOL)

    River water sources and diarrhoeic stools of residents in the Venda Region, Limpopo Province of South Africa were analysed for the prevalence of Escherichia coli (E. coli) and the presence of virulence genes among the isolates. A control group of 100 nondiarrhoeic stool samples was included. Escherichia coli was ...

  7. 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.

  8. Differentiation between Shigella, enteroinvasive Escherichia coli (EIEC) and noninvasive Escherichia coli.

    Science.gov (United States)

    van den Beld, M J C; Reubsaet, F A G

    2012-06-01

    Shigella causes bacillary dysentery and is classified into four species based on their antigen characteristics. This classification does not reflect genetic relatedness; in fact, Shigella species are so related to Escherichia coli , they should be classified as one distinctive species in the genus Escherichia. The differentiation of Shigella and E. coli is even more complicated with the description of enteroinvasive E. coli (EIEC). EIEC are strains that possess some of the biochemical characteristics of E. coli and have the ability to cause dysentery using the same method of invasion as Shigella does. Sequencing of multiple housekeeping genes indicates that EIEC is more related to Shigella than to non-invasive E. coli. Shigella and EIEC evolved from the same ancestor and form a single pathovar within E. coli. Shigella and EIEC could be separated from other E. coli by a PCR targeting the ipaH-gene; this is a multicopy gene exclusively found in all Shigella and EIEC. It is possible to differentiate Shigella and all E. coli, including EIEC, by using multiple tests, including ipaH-gene PCR, physiological and biochemical typing and serological typing. Based on literature study, a key is designed for daily use in diagnostic laboratories to identify Shigella and all E. coli.

  9. Systems Metabolic Engineering of Escherichia coli.

    Science.gov (United States)

    Choi, Kyeong Rok; Shin, Jae Ho; Cho, Jae Sung; Yang, Dongsoo; Lee, Sang Yup

    2016-05-01

    Systems metabolic engineering, which recently emerged as metabolic engineering integrated with systems biology, synthetic biology, and evolutionary engineering, allows engineering of microorganisms on a systemic level for the production of valuable chemicals far beyond its native capabilities. Here, we review the strategies for systems metabolic engineering and particularly its applications in Escherichia coli. First, we cover the various tools developed for genetic manipulation in E. coli to increase the production titers of desired chemicals. Next, we detail the strategies for systems metabolic engineering in E. coli, covering the engineering of the native metabolism, the expansion of metabolism with synthetic pathways, and the process engineering aspects undertaken to achieve higher production titers of desired chemicals. Finally, we examine a couple of notable products as case studies produced in E. coli strains developed by systems metabolic engineering. The large portfolio of chemical products successfully produced by engineered E. coli listed here demonstrates the sheer capacity of what can be envisioned and achieved with respect to microbial production of chemicals. Systems metabolic engineering is no longer in its infancy; it is now widely employed and is also positioned to further embrace next-generation interdisciplinary principles and innovation for its upgrade. Systems metabolic engineering will play increasingly important roles in developing industrial strains including E. coli that are capable of efficiently producing natural and nonnatural chemicals and materials from renewable nonfood biomass.

  10. Binding specificity of Escherichia coli trigger factor

    Science.gov (United States)

    Patzelt, Holger; Rüdiger, Stefan; Brehmer, Dirk; Kramer, Günter; Vorderwülbecke, Sonja; Schaffitzel, Elke; Waitz, Andreas; Hesterkamp, Thomas; Dong, Liying; Schneider-Mergener, Jens; Bukau, Bernd; Deuerling, Elke

    2001-01-01

    The ribosome-associated chaperone trigger factor (TF) assists the folding of newly synthesized cytosolic proteins in Escherichia coli. Here, we determined the substrate specificity of TF by examining its binding to 2842 membrane-coupled 13meric peptides. The binding motif of TF was identified as a stretch of eight amino acids, enriched in basic and aromatic residues and with a positive net charge. Fluorescence spectroscopy verified that TF exhibited a comparable substrate specificity for peptides in solution. The affinity to peptides in solution was low, indicating that TF requires ribosome association to create high local concentrations of nascent polypeptide substrates for productive interaction in vivo. Binding to membrane-coupled peptides occurred through the central peptidyl-prolyl-cis/trans isomerase (PPIase) domain of TF, however, independently of prolyl residues. Crosslinking experiments showed that a TF fragment containing the PPIase domain linked to the ribosome via the N-terminal domain is sufficient for interaction with nascent polypeptide substrates. Homology modeling of the PPIase domain revealed a conserved FKBP(FK506-binding protein)-like binding pocket composed of exposed aromatic residues embedded in a groove with negative surface charge. The features of this groove complement well the determined substrate specificity of TF. Moreover, a mutation (E178V) in this putative substrate binding groove known to enhance PPIase activity also enhanced TF's association with a prolyl-free model peptide in solution and with nascent polypeptides. This result suggests that both prolyl-independent binding of peptide substrates and peptidyl-prolyl isomerization involve the same binding site. PMID:11724963

  11. Escherichia coli in broiler chickens with airsacculitis

    Directory of Open Access Journals (Sweden)

    Leandro S. Machado

    2014-09-01

    Full Text Available ABSTRACT. Machado L.S., do Nascimento E.R., Pereira V.L.A., Abreu D.L.C., Gouvea R. & Santos L.M.M. 2014. [Escherichia coli in broiler chickens with airsacculitis.] Escherichia coli em frangos de corte com aerossaculite. Revista Brasileira de Medicina Veterinária, 36(3:261-265, 2014. Departamento de Medicina Veterinária Preventiva e Saúde Pública, Faculdade de Veterinária, Universidade Federal Fluminense, Rua Dr. Vital Brazil Filho 64, Vital Brazil, Niterói, RJ 24230-340, Brazil. E-mail: leandromachadovet@yahoo.com.br The Brazilian poultry industry grows each year and becomes increasingly representative in the production and export of products. The health care with poultry have accompanied and favored this evolution, however, respiratory agents that affect the weight and carcass quality, continue to cause great damage to the poultry industry. Airsacculitis is considered the main cause of total and partial condemnation of carcasses of broilers, and has been attributed to Mycoplasmosis mostly caused by Mycoplasma gallisepticum (MG and Mycoplasma synoviae (MS and Escherichia coli. The aim of this study was to relate the positivity of MG / MS and E. coli detected by PCR as a risk factor for airsacculitis in condemnation of broilers in Health Inspection Service. We studied 30 broiler poultry slaughtered in a slaughterhouse under Federal Sanitary Inspection, located in the State of Rio de Janeiro. 30 chickens were randomly collected from different lots and tracheas obtained in each PCR. DNA was extracted by phenol-chloroform method and amplified using pairs of “primer”specific for MG, MS and E. coli. Of the 30 chickens analyzed by PCR, 30% (9/30 had lesions in air sacs. None of the birds showed infection with MG and/or MS PCR, however 33.3% (3/9 birds were positive for airsacculitis iss gene from E.coli. E.coli found in broiler chickens that were negative for mycoplasma airsacculitis, implying the presence of such bacteria may be sufficient

  12. Plasmid-Mediated Quinolone Resistance Genes in Escherichia coli ...

    African Journals Online (AJOL)

    PMQR) genes and the prevalence of extended spectrum β-lactamase (ESBL) types in Escherichia coli clinical isolates. Methods: Sixty-one ESBL-producing urinary E. coli isolates were studied. An antibiotic susceptibility test was performed ...

  13. Genetic diversity of Escherichia coli isolated from commercial swine ...

    African Journals Online (AJOL)

    PCR) for the analysis of genetic diversity among Escherichia coli strains isolated from commercial swine farms in Sichuan province of China. Thirty four strains of E. coli were selected by selective medium and conventional biochemical test from ...

  14. 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...

  15. [Transformation of phosphotransferase system in Escherichia coli].

    Science.gov (United States)

    Xiao, Mengrong; Zhang, Liang; Liu, Shuangping; Shi, Guiyang

    2014-10-01

    We constructed several recombinant Escherichia coli strains to transform phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS system) and compared the characteristics of growth and metabolism of the mutants. We knocked-out the key genes ptsI and ptsG in PTS system by using Red homologous recombination in E. coli and meanwhile we also knocked-in the glucose facilitator gene glf from Zymomonas mobilis in the E. coli chromosome. Recombinant E. coli strains were constructed and the effects of cell growth, glucose consumption and acetic acid accumulation were also evaluated in all recombinant strains. The deletion of gene ptsG and ptsI inactivated some PTS system functions and inhibited the growth ability of the cell. Expressing the gene glf can help recombinant E. coli strains re-absorb the glucose through Glf-Glk (glucose facilitator-glucokinase) pathway as it can use ATP to phosphorylate glucose and transport into cell. This pathway can improve the availability of glucose and also reduce the accumulation of acetic acid; it can also broaden the carbon flux in the metabolism pathway.

  16. Escherichia coli fimbriae recognizing sialyl galactosides.

    Science.gov (United States)

    Korhonen, T K; Väisänen-Rhen, V; Rhen, M; Pere, A; Parkkinen, J; Finne, J

    1984-08-01

    Fimbriae recognizing sialyl galactosides (S fimbriae) were purified from an Escherichia coli strain. The S fimbriae were morphologically identical to type 1 and P fimbriae of E. coli and showed a hemagglutination that was abolished when erythrocytes were treated with neuraminidase. Hemagglutination by the purified fimbriae was inhibited by orosomucoid but not by its desialylated derivative. Of the oligosaccharides tested, sialyl-(alpha 2-3)-lactose and sialyl-(alpha 2-3)-N-acetyllactosamine had the strongest inhibitory activities. It was concluded that S fimbriae have the strongest affinity for (alpha 2-3)-linked sialyl galactosides. In the enzyme-linked immunosorbent assay, the hyperimmune serum to the S fimbriae reacted strongly with the homologous antigen but not with type 1, P, or nonhemagglutinating KS71C fimbriae of E. coli. Analogously, the hyperimmune sera to the other E. coli fimbriae did not react with the purified S fimbriae. The immunoprecipitation assay showed that S fimbriae on different E. coli serotypes shared immunological cross-reactivity.

  17. Photoinactivation of mcr-1 positive Escherichia coli

    Science.gov (United States)

    Caires, C. S. A.; Leal, C. R. B.; Rodrigues, A. C. S.; Lima, A. R.; Silva, C. M.; Ramos, C. A. N.; Chang, M. R.; Arruda, E. J.; Oliveira, S. L.; Nascimento, V. A.; Caires, A. R. L.

    2018-01-01

    The emergence of plasmid-mediated colistin resistance in Enterobacteriaceae, mostly in Escherichia coli due to the mcr-1 gene, has revealed the need to develop alternative approaches in treating mcr-1 positive bacterial infections. This is because colistin is a broad-spectrum antibiotic and one of the ‘last-resort’ antibiotics for multidrug resistant bacteria. The present study evaluated for the first time, to the best of our knowledge, the efficacy of photoinactivation processes to kill a known mcr-1 positive E. coli strain. Eosin methylene-blue (EMB) was investigated as a photoantimicrobial agent for inhibiting the growth of a mcr-1 positive E. coli strain obtained from a patient with a diabetic foot infection. The photoantimicrobial activity of EMB was also tested in a non-multidrug resistant E. coli strain. The photoinactivation process was tested using light doses in the 30–45 J cm‑2 range provided by a LED device emitting at 625 nm. Our findings demonstrate that a mcr-1 positive E. coli strain is susceptible to photoinactivation. The results show that the EMB was successfully photoactivated, regardless of the bacterial multidrug resistance; inactivating the bacterial growth by oxidizing the cells in accordance with the generation of the oxygen reactive species. Our results suggest that bacterial photoinactivation is an alternative and effective approach to kill mcr-1 positive bacteria.

  18. Current Interventions for Controlling Pathogenic Escherichia coli.

    Science.gov (United States)

    Kim, Nam Hee; Cho, Tae Jin; Rhee, Min Suk

    2017-01-01

    This review examined scientific reports and articles published from 2007 to 2016 regarding the major environmental sources of pathogenic Escherichia coli and the routes by which they enter the human gastrointestinal tract. The literature describes novel techniques used to combat pathogenic E. coli transmitted to humans from livestock and agricultural products, food-contact surfaces in processing environments, and food products themselves. Although prevention before contamination is always the best "intervention," many studies aim to identify novel chemical, physical, and biological techniques that inactivate or eliminate pathogenic E. coli cells from breeding livestock, growing crops, and manufactured food products. Such intervention strategies target each stage of the food chain from the perspective of "Farm to Table food safety" and aim to manage major reservoirs of pathogenic E. coli throughout the entire process. Issues related to, and recent trends in, food production must address not only the safety of the food itself but also the safety of those who consume it. Thus, research aims to discover new "natural" antimicrobial agents and to develop "multiple hurdle technology" or other novel technologies that preserve food quality. In addition, this review examines the practical application of recent technologies from the perspective of product quality and safety. It provides comprehensive insight into intervention measures used to ensure food safety, specifically those aimed at pathogenic E. coli. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. DamX Controls Reversible Cell Morphology Switching in Uropathogenic Escherichia coli

    DEFF Research Database (Denmark)

    Khandige, Surabhi; Antoinette Asferg, Cecilie; Rasmussen, Karina Juhl

    2016-01-01

    UNLABELLED: The ability to change cell morphology is an advantageous characteristic adopted by multiple pathogenic bacteria in order to evade host immune detection and assault during infection. Uropathogenic Escherichia coli (UPEC) exhibits such cellular dynamics and has been shown to transition...... undertaking targeted investigations that are challenging to perform in animal infection models. IMPORTANCE: Urinary tract infections (UTIs) are most often caused by uropathogenic Escherichia coli (UPEC) and account for a considerable health care burden. UPEC exhibits a dynamic lifestyle in the course......A-mediated FtsZ sequestration during E. coli uropathogenesis, and hence represents a potential target for combating UTI....

  20. Phenotypic Changes Exhibited by E. coli Cultured in Space

    DEFF Research Database (Denmark)

    Zea, Luis; Larsen, Michael; Estante, Frederico

    2017-01-01

    Bacteria will accompany humans in our exploration of space, making it of importance to study their adaptation to the microgravity environment. To investigate potential phenotypic changes for bacteria grown in space, Escherichia coli was cultured onboard the International Space Station with matche...

  1. Translational coupling in Escherichia coli of a heterologous Bacillus subtilis-Escherichia coli gene fusion.

    OpenAIRE

    Zaghloul, T I; Doi, R H

    1986-01-01

    The efficient expression in Escherichia coli of the Tn9-derived chloramphenicol acetyltransferase (EC 2.3.1.28) gene fused distal to the promoter and N terminus of the Bacillus subtilis aprA gene was dependent on the initiation of translation from the ribosome-binding site in the aprA gene.

  2. 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.

  3. Genetic relationship of diarrheagenic Escherichia coli pathotypes among the enteropathogenic Escherichia coli O serogroup

    Directory of Open Access Journals (Sweden)

    Silvia Y Bando

    2007-03-01

    Full Text Available The genetic relationship among the Escherichia coli pathotypes was investigated. We used random amplified polymorphic DNA (RAPD data for constructing a dendrogram of 73 strains of diarrheagenic E. coli. A phylogenetic tree encompassing 15 serotypes from different pathotypes was constructed using multilocus sequence typing data. Phylogram clusters were used for validating RAPD data on the clonality of enteropathogenic E. coli (EPEC O serogroup strains. Both analyses showed very similar topologies, characterized by the presence of two major groups: group A includes EPEC H6 and H34 strains and group B contains the other EPEC strains plus all serotypes belonging to atypical EPEC, enteroaggregative E. coli (EAEC and enterohemorrhagic E. coli (EHEC. These results confirm the existence of two evolutionary divergent groups in EPEC: one is genetically and serologically very homogeneous whereas the other harbors EPEC and non-EPEC serotypes. The same situation was found for EAEC and EHEC.

  4. 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...... temporal progression from origin to terminus. Thus, the overall pattern is one of continuous segregation during replication and is not consistent with recently published models invoking extensive sister chromosome cohesion followed by simultaneous segregation of the bulk of the chromosome. The terminus...

  5. Incomplete flagellar structures in Escherichia coli mutants.

    OpenAIRE

    Suzuki, T; Komeda, Y

    1981-01-01

    Escherichia coli mutants with defects in 29 flagellar genes identified so far were examined by electron microscopy for possession of incomplete flagellar structures in membrane-associated fractions. The results are discussed in consideration of the known transcriptional interaction of flagellar genes. Hook-basal body structures were detected in flaD, flaS, flaT, flbC, and hag mutants. The flaE mutant had a polyhook-basal body structure. An intact basal body appeared in flaK mutants. Putative ...

  6. Global gene expression in Escherichia coli biofilms

    DEFF Research Database (Denmark)

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

    2003-01-01

    It is now apparent that microorganisms undergo significant changes during the transition from planktonic to biofilm growth. These changes result in phenotypic adaptations that allow the formation of highly organized and structured sessile communities, which possess enhanced resistance...... to 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...... 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 genes altered...

  7. Natural DNA uptake by Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Sunita Sinha

    Full Text Available Escherichia coli has homologues of the competence genes other species use for DNA uptake and processing, but natural competence and transformation have never been detected. Although we previously showed that these genes are induced by the competence regulator Sxy as in other gamma-proteobacteria, no conditions are known that naturally induce sxy expression. We have now tested whether the competence gene homologues encode a functional DNA uptake machinery and whether DNA uptake leads to recombination, by investigating the effects of plasmid-borne sxy expression on natural competence in a wide variety of E. coli strains. High- and low-level sxy expression alone did not induce transformation in any of the strains tested, despite varying the transforming DNA, its concentration, and the incubation conditions used. Direct measurements of uptake of radiolabelled DNA were below the limit of detection, however transformants were readily detected when recombination functions were provided by the lambda Red recombinase. This is the first demonstration that E. coli sxy expression can induce natural DNA uptake and that E. coli's competence genes do encode a functional uptake machinery. However, the amount of transformation cells undergo is limited both by low levels of DNA uptake and by inefficient DNA processing/recombination.

  8. Engineering Escherichia coli for methanol conversion.

    Science.gov (United States)

    Müller, Jonas E N; Meyer, Fabian; Litsanov, Boris; Kiefer, Patrick; Potthoff, Eva; Heux, Stéphanie; Quax, Wim J; Wendisch, Volker F; Brautaset, Trygve; Portais, Jean-Charles; Vorholt, Julia A

    2015-03-01

    Methylotrophic bacteria utilize methanol and other reduced one-carbon compounds as their sole source of carbon and energy. For this purpose, these bacteria evolved a number of specialized enzymes and pathways. Here, we used a synthetic biology approach to select and introduce a set of "methylotrophy genes" into Escherichia coli based on in silico considerations and flux balance analysis to enable methanol dissimilation and assimilation. We determined that the most promising approach allowing the utilization of methanol was the implementation of NAD-dependent methanol dehydrogenase and the establishment of the ribulose monophosphate cycle by expressing the genes for hexulose-6-phosphate synthase (Hps) and 6-phospho-3-hexuloisomerase (Phi). To test for the best-performing enzymes in the heterologous host, a number of enzyme candidates from different donor organisms were selected and systematically analyzed for their in vitro and in vivo activities in E. coli. Among these, Mdh2, Hps and Phi originating from Bacillus methanolicus were found to be the most effective. Labeling experiments using (13)C methanol with E. coli producing these enzymes showed up to 40% incorporation of methanol into central metabolites. The presence of the endogenous glutathione-dependent formaldehyde oxidation pathway of E. coli did not adversely affect the methanol conversion rate. Taken together, the results of this study represent a major advancement towards establishing synthetic methylotrophs by gene transfer. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  9. 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....

  10. Multiple antimicrobial resistance of Escherichia coli and Salmonella ...

    African Journals Online (AJOL)

    ADEYEYE

    2017-07-11

    Jul 11, 2017 ... verocytotoxin-producing Escherichia coli. O157 from slaughter pigs and poultry. International Journal of Food Microbiology,. 52(1 – 2): 67 – 75. Huang TM, Lin TL & Wu CC (2009). Antimicrobial susceptibility and resistance of chicken. Escherichia coli, Salmonella spp., and. Pasteurella multocida isolates.

  11. 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

  12. Prevalence of Escherichia coli some public water sources in Gusau ...

    African Journals Online (AJOL)

    This study investigated the presence of Escherichia coli from some public water sources in Gusau municipal, north- western Nigeria. This was done by determining the total coliform counts and the presence of Escherichia coli and its antibiotic susceptibility profile. A total of 180 well 60 tap and 60 packaged water samples ...

  13. Inactivation of Escherichia coli by citral.

    Science.gov (United States)

    Somolinos, M; García, D; Condón, S; Mackey, B; Pagán, R

    2010-06-01

    The aim was to evaluate (i) the resistance of Escherichia coli BJ4 to citral in a buffer system as a function of citral concentration, treatment medium pH, storage time and initial inoculum size, (ii) the role of the sigma factor RpoS on citral resistance of E. coli, (iii) the role of the cell envelope damage in the mechanism of microbial inactivation by citral and (iiii) possible synergistic effects of mild heat treatment and pulsed electric fields (PEF) treatment combined with citral. The initial inoculum size greatly affected the efficacy of citral against E. coli cells. Exposure to 200 microl l(-1) of citral at pH 4.0 for 24 h at 20 degrees C caused the inactivation of more than 5 log(10) cycles of cells starting at an inoculum size of 10(6) or 10(7) CFU ml(-1), whereas increasing the cell concentration to 10(9) CFU ml(-1) caused citral at pH 4.0 than pH 7.0. The rpoS null mutant strain E. coli BJ4L1 was less resistant to citral than the wild-type strain. Occurrence of sublethal injury to both the cytoplasmic and outer membranes was demonstrated by adding sodium chloride or bile salts to the recovery media. The majority of sublethally injured cells by citral required energy and lipid synthesis for repair. A strongly synergistic lethal effect was shown by mild heat treatment combined with citral but the presence of citral during the application of a PEF treatment did not show any advantage. This work confirms that cell envelope damage is an important event in citral inactivation of bacteria, and it describes the key factors on the inactivation of E. coli cells by citral. Knowledge about the mechanism of microbial inactivation by citral helps establish successful combined preservation treatments.

  14. 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

  15. [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.

  16. Isolation of Enteropathogenic Escherichia coli from lettuce samples in Tehran

    OpenAIRE

    Mazaheri, Somayeh; Salmanzadeh-Ahrabi, Siavosh; Falsafi, Tahereh; Aslani, Mohammad-Mehdi

    2014-01-01

    Aim The purpose of this study was to find the isolation rate of enteropathogenic Escherichia coli (EPEC) from lettuce samples collected in Tehran. Background During the last decade, the prevalence of infectious diarrheal diseases due to consumption of contaminated food especially raw vegetable has been increasingly reported. Enteropathogenic Escherichia coli strains are an important group of diarrheagenic E. coli that can cause infant diarrhea especially in the developing world. Material and ...

  17. Recombinant Protein Expression in Escherichia coli (E.coli): What We Need to Know.

    Science.gov (United States)

    Hayat, Seyed Mohammad Gheibi; Farahani, Najmeh; Golichenari, Behrouz; Sahebkar, Amir Hosein

    2018-01-31

    Host, vector, and culture conditions (including cultivation media) are considered among the three main elements contributing to a successful production of recombinant proteins. Accordingly, one of the most common hosts to produce recombinant therapeutic proteins is Escherichia coli. A comprehensive literature review was performed to identify important factors affecting production of recombinant proteins in Escherichia coli. Escherichia coli is taken into account as the easiest, quickest, and cheapest host with a fully known genome. Thus, numerous modifications have been carried out on Escherichia coli to optimize it as a good candidate for protein expression and; as a result, several engineered strains of Escherichia coli have been designed. In general; host strain, vector, and cultivation parameters are recognized as crucial ones determining success of recombinant protein expression in Escherichia coli. In this review, the role of host, vector, and culture conditions along with current pros and cons of different types of these factors leading to success of recombinant protein expression in Escherichia coli were discussed. Successful protein expression in Escherichia coli necessitates a broad knowledge about physicochemical properties of recombinant proteins, selection among common strains of Escherichia coli and vectors, as well as factors related to media including time, temperature, and inducer. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  18. Changes in Escherichia coli resistance to co-trimoxazole in ...

    African Journals Online (AJOL)

    Escherichia coli (E.coli) resistance to co-trimoxazole in TB patients changed with time and ii) whether the resistance pattern was different in HIV positive TB patients who were taking co-trimoxazole prophylaxis. Co-trimoxazole resist- ance among E.coli isolates in TB patients at the time of reg- istration was 60% in 1999 and ...

  19. Isolation and genomic characterization of Escherichia coli O157:NM ...

    African Journals Online (AJOL)

    Human diseases caused by Escherichia coli O157:NM and E. coli O157:H7 strains have been reported throughout the world. In developed countries, serotype O157:H7 represents the major cause of human diseases; however, there have been increasing reports of non-O157 Shiga toxin (Stx)-producing E. coli strains ...

  20. Isolation and Antibiotics Susceptibility Patterns of Escherichia Coli ...

    African Journals Online (AJOL)

    Escherichia coli 0157.H7 were confirmed serologically using latex agglutination kits (OxoidR UK). The isolates were tested for susceptibility to five commonly used antimicrobial agents and plasmid transfer was also carried out using E. coli K12 356 recipient. Out of the 61 non-Sorbitol fermenting (NSF) E. coli isolated from ...

  1. Neonatal infections caused by Escherichia coli at the National ...

    African Journals Online (AJOL)

    Background: Escherichia coli (E.coli) has been implicated as a common cause of both early and late onset neonatal infections. The emergence of different strains of E.coli that are multiply resistant to commonly used antibiotics has made continuous antibiotics surveillance relevant. Knowledge about common infections ...

  2. Increased multi-drug resistant Escherichia coli from hospitals in ...

    African Journals Online (AJOL)

    Background: Multidrug-resistant Escherichia coli (MDR E. coli) has become a major public health concern in Sudan and many countries, causing failure in treatment with consequent huge health burden. Objectives: To determine the prevalence and susceptibility of MDR E. coli isolated from patients in hospitals at Khartoum ...

  3. 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.

  4. 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 incredibly big molecule and separate the two daughter chromosomes and how it makes sure that the daughter cells receives one copy each. The fully extended chromosome is two orders of magnitude larger than the cell in which it is contained. Hence the chromosome is heavily compacted in the cell......, and it is obvious that structured cellular actions are required to unpack it, as required for its replication, and refold the two daughter chromosomes separately without getting them entangled in the process each generation. The intention of the study was initially to find out how the chromosome is organized...

  5. Engineering membrane protein overproduction in Escherichia coli

    Science.gov (United States)

    Molina, Daniel Martinez; Cornvik, Tobias; Eshaghi, Said; Haeggström, Jesper Z.; Nordlund, Pär; Sabet, Marina Ignatushchenko

    2008-01-01

    Membrane proteins play a fundamental role in human disease and therapy, but suffer from a lack of structural and functional information compared to their soluble counterparts. The paucity of membrane protein structures is primarily due to the unparalleled difficulties in obtaining detergent-solubilized membrane proteins at sufficient levels and quality. We have developed an in vitro evolution strategy for optimizing the levels of detergent-solubilized membrane protein that can be overexpressed and purified from recombinant Escherichia coli. Libraries of random mutants for nine membrane proteins were screened for expression using a novel implementation of the colony filtration blot. In only one cycle of directed evolution were significant improvements of membrane protein yield obtained for five out of nine proteins. In one case, the yield of detergent-solubilized membrane protein was increased 40-fold. PMID:18305199

  6. Initiation of Replication in Escherichia coli

    DEFF Research Database (Denmark)

    Frimodt-Møller, Jakob

    of initiation, which leads to hyperinitiation, results in double-strand breaks when replication forks encounters single-stranded DNA lesions generated while removing oxidized bases, primarily 8-oxoG, from the DNA. Thus, the number of replication forks can only increase when ROS formation is reduced or when......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...

  7. Characterization of plasmid mediated AmpC producing Escherichia coli clinical isolates from a tertiary care hospital in South India

    National Research Council Canada - National Science Library

    Chakraborty, Arindam; Adhikari, Prabha; Shenoy, Shalini; Saralaya, Vishwas

    2014-01-01

    Plasmid mediated AmpC (pAmpC) β-lactamase producing Escherichia coli are an emerging problem worldwide as they are now exhibiting resistance to multiple classes of antibiotics and are a major cause of therapeutic failure...

  8. Marine macroalgae as a source for osmoprotection for Escherichia coli.

    Science.gov (United States)

    Ghoul, M; Minet, J; Bernard, T; Dupray, E; Cormier, M

    1995-09-01

    At elevated osmolarity of the mineral medium M63, marine macroalgae constitute important osmoprotectants and nutrients sources for Escherichia coli. Growth of bacterial population (16 strains) was improved by supplementing M63 salts medium with either aqueous or ethanolic algal extracts obtained from Ascophyllum nodosum, Fucus serratus, Enteromorpha ramulosa, Ulva lactuca, and Palmaria palmata. In their presence, growth was still observed even at 1.02 M NaCl. Furthermore, the E. coli ZB400 growth in presence of whole macroalgae thalli in M63/0.85 M NaCI reached its maximum within 24 h (5 × 10(7) - 5 × 10(8) colony-forming units [CFU] per milliliter). In the presence of A. nodosum, bacterial growth was inhibited. In the same experimental conditions, ethanolic extracts improved E. coli growth significantly, because the yield reached 10(11) CFU per milliliter. Ulva lactuca and P. palmata allowed the better growth. The Dragendorff-positive compounds extracted from bacterial cells growing on each ethanolic extract exhibited an osmoprotective effect as proved by a disk-diffusion assay. On the other hand, the -onium compounds (quaternary ammonium [betaines] and tertiary sulphonium) and total free amino acid contents of U. lactuca ethanolic extracts were higher than in others. Fucaceae extracts demonstrated especially high protein content. Algal extracts constitute not only an appreciable osmoprotection source for E. coli but also nutrient sources.

  9. Escherichia coli enterotoxin. Purification and partial characterization.

    Science.gov (United States)

    Dorner, F

    1975-11-25

    Enterotoxin, a diarrheagenic protein elaborated by pathogenic Escherichia coli strains has been isolated from the supernatant of fermenter cultures of E. coli strain P263, a porcine enteropathogen. Purification steps involving Bio-Gel agarose A-5m, Sephadex G-75 chromatography, and preparative isotachophoresis were used in the isolation. The resulting product appears to be pure according to immunoelectrophoretic, disc electrophoretic, ultracentrifugal, and immunologic criteria. The entertoxin has an apparent molecular weight of 102,000 as judged by gel filtration and sodium dodecyl sulfate polyacrylamide gel electrophoresis, and its isoelectric point is 6.90. The isolated product is highly active in inducing experimental diarrhea in adult rabbits and piglets. It also elicits, in small dosage, a marked increase in adenylate cyclase activity in broken cell preparations of cat heart tissue. The enterotoxin activity is acid-labile and is destroyed by heating at 65 degrees for 30 min. It is suggested that the heat-stable enterotoxin material is derived from heat-labile enterotoxin by forming a complex with endotoxin or capsular material present in the culture supernatant.

  10. 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.

  11. Cloning and expression of Pseudomonas aeruginosa flagellin in Escherichia coli.

    OpenAIRE

    Kelly-Wintenberg, K; Montie, T. C.

    1989-01-01

    The flagellin gene was isolated from a Pseudomonas aeruginosa PAO1 genomic bank by conjugation into a PA103 Fla- strain. Flagellin DNA was transferred from motile recipient PA103 Fla+ cells by transformation into Escherichia coli. We show that transformed E. coli expresses flagellin protein. Export of flagellin to the E. coli cell surface was suggested by positive colony blots of unlysed cells and by isolation of flagellin protein from E. coli supernatants.

  12. 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.

  13. Complete Genome Sequence of Escherichia coli Strain WG5

    DEFF Research Database (Denmark)

    Imamovic, Lejla; Misiakou, Maria-Anna; van der Helm, Eric

    2018-01-01

    Escherichia coli strain WG5 is a widely used host for phage detection, including somatic coliphages employed as standard ISO method 10705-1 (2000). Here, we present the complete genome sequence of a commercial E. coli WG5 strain.......Escherichia coli strain WG5 is a widely used host for phage detection, including somatic coliphages employed as standard ISO method 10705-1 (2000). Here, we present the complete genome sequence of a commercial E. coli WG5 strain....

  14. Escherichia coli survival in waters: temperature dependence.

    Science.gov (United States)

    Blaustein, R A; Pachepsky, Y; Hill, R L; Shelton, D R; Whelan, G

    2013-02-01

    Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q₁₀ model. This suggestion was made 34 years ago based on 20 survival curves taken from published literature, but has not been revisited since then. The objective of this study was to re-evaluate the accuracy of the Q₁₀ equation, utilizing data accumulated since 1978. We assembled a database of 450 E. coli survival datasets from 70 peer-reviewed papers. We then focused on the 170 curves taken from experiments that were performed in the laboratory under dark conditions to exclude the effects of sunlight and other field factors that could cause additional variability in results. All datasets were tabulated dependencies "log concentration vs. time." There were three major patterns of inactivation: about half of the datasets had a section of fast log-linear inactivation followed by a section of slow log-linear inactivation; about a quarter of the datasets had a lag period followed by log-linear inactivation; and the remaining quarter were approximately linear throughout. First-order inactivation rate constants were calculated from the linear sections of all survival curves and the data grouped by water sources, including waters of agricultural origin, pristine water sources, groundwater and wells, lakes and reservoirs, rivers and streams, estuaries and seawater, and wastewater. Dependency of E. coli inactivation rates on temperature varied among the water sources. There was a significant difference in inactivation rate values at the reference temperature between rivers and agricultural waters, wastewaters and agricultural waters, rivers and lakes, and wastewater and lakes. At specific sites, the Q₁₀ equation was more accurate in rivers and coastal waters than in lakes making the value of

  15. 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.

  16. WGS accurately predicts antimicrobial resistance in Escherichia coli

    National Research Council Canada - National Science Library

    Tyson, Gregory H; McDermott, Patrick F; Li, Cong; Chen, Yuansha; Tadesse, Daniel A; Mukherjee, Sampa; Bodeis-Jones, Sonya; Kabera, Claudine; Gaines, Stuart A; Loneragan, Guy H; Edrington, Tom S; Torrence, Mary; Harhay, Dayna M; Zhao, Shaohua

    2015-01-01

    The objective of this study was to determine the effectiveness of WGS in identifying resistance genotypes of MDR Escherichia coli and whether these correlate with observed phenotypes. Seventy-six E...

  17. Antibiotic resistance of Escherichia coli, Listeria and Salmonella ...

    African Journals Online (AJOL)

    Antibiotic resistance of Escherichia coli, Listeria and Salmonella isolates from retail ... Antibiotics sensitivity test was assayed on thirty (30) isolates (10 each for ... their way into human population through food chain and occupational exposure.

  18. Switchable gene expression in Escherichia coli using a miniaturized photobioreactor

    National Research Council Canada - National Science Library

    Lee, Jae Myung; Lee, Junhyeong; Kim, Taesung; Lee, Sung Kuk

    2013-01-01

    We present a light-switchable gene expression system for both inducible and switchable control of gene expression at a single cell level in Escherichia coli using a previously constructed light-sensing system. The λ...

  19. The Prevalence of Enterhaemorrhagic Escherichia Coli in children ...

    African Journals Online (AJOL)

    EHEC), the pathogenicity of other strains of Escherichia coli and other organisms in children presenting with and without diarrhoea in the hospital. Subjects and Methods: A total of 247 stool samples collected from children aged 1 month to 7 ...

  20. Nanotextile membranes for bacteria Escherichia coli capturing

    Directory of Open Access Journals (Sweden)

    Jaroslav Lev

    2010-01-01

    Full Text Available The article describes an experimental study dealing with the possibility of nanotextile materials usa­ge for microbiologically contaminated water filtration. The aim of the study is to verify filtration ability of different nanotextile materials and evaluate the possibilities of practical usage. Good detention ability of these materials in the air filtration is the presumption for nanotextile to be used for bacteria filtration from a liquid. High nanotextile porosity with the nanotextile pores dimensions smaller than a bacteria size predicates the possibility of a successful usage of these materials. For the experiment were used materials made from electrospinning nanofibres under the label PA612, PUR1, PUR2 s PUR3 on the supporting unwoven textiles (viscose and PP. As a model simulation of the microbial contamination, bacteria Escherichia coli was chosen. Contaminated water was filtered during the overpressure activity of 105Pa on the input side of the filter from the mentioned material. After three-day incubation on the nutrient medium, cultures found in the samples before and after filtration were compared. In the filtrated water, bacteria E. coli were indicated, which did not verify the theoretical presumptions about an absolut bacteria detention. However, used materials caught at least 94% of bacteria in case of material PUR1 and up to 99,996% in case of material PUR2. These results predict the possibility of producing effective nanotextile filters for microbiologically contaminated water filtration.Recommendation: For the production of materials with better filtrating qualities, experiments need to be done, enabling better understanding of the bacteria detention mechanisms on the nanotextile material, and parameters of the used materials that influence the filtrating abilities need to be verified.

  1. Antibacterial Actions of Glycinin Basic Peptide against Escherichia coli.

    Science.gov (United States)

    Zhao, Guo-Ping; Li, Ying-Qiu; Sun, Gui-Jin; Mo, Hai-Zhen

    2017-06-28

    Glycinin basic peptide (GBP) is an antibacterial ingredient that occurs naturally in the basic parts of soybean glycinin. The antibacterial actions of GBP against Escherichia coli ATCC 8739 were investigated in this study. The minimum inhibitory concentration of GBP against E. coli was 200 μg/mL. The exposure of E. coli cells to GBP induced significant cell damage and inactivated intracellular esterases (stressed and dead cells, 70.9% ± 0.04 for 200 μg/mL of GBP and 91.9% ± 0.06 for 400 μg/mL of GBP), as determined through dual staining in flow cytometry. GBP resulted in the exposure of phosphatidylserine in E. coli cells. The analyses of flow cytometry-manifested GBP treatment led to the shrinkage of the cell surface and the complication of cell granularity. The observations in transmission electron microscopy demonstrated that 400 μg/mL of GBP severely disrupted the membrane integrity, resulting in ruptures or pores in the membrane, outflows of intracellular contents, or aggregation of the cytoplasm. Release of alkaline phosphatase, lipopolysaccharide, and reducing sugar further verified that the membrane damage was due to GBP. In addition, GBP treatment changed the helicity and base staking of DNA, as determined by circular dichroism spectroscopy. These results showed that GBP had strong antibacterial activity against E. coli via membrane damage and DNA perturbation. Additionally, GBP exhibited no cytotoxicity on the viability of human embryonic kidney cells. Thus, GBP may be a promising candidate as a natural antibacterial agent.

  2. Escherichia coli challenge in newborn pigs.

    Science.gov (United States)

    Jensen, M L; Cilieborg, M S; Østergaard, M V; Bering, S B; Jørgensen, C B; Sangild, P T

    2012-12-01

    Escherichia coli F18 is a common porcine enteric pathogen causing diarrhea and edema in weaned pigs. An essential step in the pathogenesis of this enteric colibacillosis is a fimbria-receptor interaction in the small intestine, involving the α(1,2)-fucosyltransferase gene (FUT1) enzyme for bacterial receptor binding to the epithelium. Enzyme expression is genetically determined and increases after weaning at 3 to5 wk, probably due to age- and/or diet-related intestinal maturation. We hypothesized that artificially reared piglets, deprived of sow's milk from birth, show susceptibility to F18 already in the neonatal period. First we verified the intestinal expression of FUT1 in preterm, term, and weaned pigs by quantitative real-time polymerase chain reaction. Then age-related F18 susceptibility (degree of diarrhea) was evaluated in 3-, 10-, and 20-d-old pigs after inoculation of 10(10) cfu E. coli F18 per day for 12 d. Finally, F18 susceptibility was evaluated in caesarean-delivered 0- to 7-d-old piglets inoculated daily with F18 as above. For all pigs, their sows were genotyped to ensure expression of the FUT1 enzyme. FUT1 expression was detected in the proximal and distal small intestine with no apparent differences in levels among preterm, term, and weaned pigs. No consistent F18-induced diarrhea was detected in any of the 3 groups of 3- to 20-d-old pigs. In contrast, 0- to 7-d-old caesarean-delivered pigs showed a higher score of diarrhea in pigs inoculated with F18 compared with controls (2.4 ± 0.1 vs. 1.8 ± 0.1 respectively; P sow milk are highly susceptible to diarrhea induced by E. coli F18. Lack of the protective effects of birth colonization and sow milk may contribute to high intestinal F18 sensitivity. The newborn pig may be a useful model to investigate factors in maternal milk that protect against F18 diarrhea.

  3. Completion of DNA replication in Escherichia coli.

    Science.gov (United States)

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

    2014-11-18

    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.

  4. 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. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  5. Genotoxicity of Graphene in Escherichia coli

    Science.gov (United States)

    Sharma, Ananya

    Rapid advances in nanotechnology necessitate assessment of the safety of nanomaterials in the resulting products and applications. One key nanomaterial attracting much interest in many areas of science and technology is graphene. Graphene is a one atom thick carbon allotrope arranged in a two-dimensional honeycomb lattice. In addition to being extremely thin, graphene has several extraordinary physical properties such as its exceptional mechanical strength, thermal stability, and high electrical conductivity. Graphene itself is relatively chemically inert and therefore pristine graphene must undergo a process called functionalization, which is combination of chemical and physical treatments that change the properties of graphene, to make it chemically active. Functionalization of graphene is of crucial importance as the end application of graphene depends on proper functionalization. In the field of medicine, graphene is currently a nanomaterial of high interest for building biosensors, DNA transistors, and probes for cancer detection. Despite the promising applications of graphene in several areas of biomedicine, there have been only few studies in recent years that focus on evaluating cytotoxicity of graphene on cells, and almost no studies that investigate how graphene exposure affects cellular genetic material. Therefore, in this study we used a novel approach to evaluate the genotoxicity, i.e., the effects of graphene on DNA, using Escherichia coli as a prokaryotic model organism.

  6. Changes in Escherichia coli resistance to co-trimoxazole in ...

    African Journals Online (AJOL)

    In Thyolo district, Malawi, an operational research study is being conducted on the efficacy and feasibility of co-trimoxazole prophylaxis in preventing deaths in HIV-positive patients with tuberculosis (TB). A series of cross-sectional studies were carried out to determine i) whether faecal Escherichia coli (E.coli) resistance to ...

  7. Enterotoxigenic Escherichia coli Multilocus Sequence Types in Guatemala and Mexico

    Science.gov (United States)

    Klena, John; Rodas, Claudia; Bourgeois, August Louis; Torres, Olga; Svennerholm, Ann-Mari; Sjöling, Åsa

    2010-01-01

    The genetic backgrounds of 24 enterotoxigenic Escherichia coli (ETEC) strains from Mexico and Guatemala expressing heat-stable toxin (ST) and coli surface antigen 6 (CS6) were analyzed. US travelers to these countries and resident children in Guatemala were infected by ETEC strains of sequence type 398, expressing STp and carrying genetically identical CS6 sequences. PMID:20031063

  8. Multiple antimicrobial resistance of Escherichia coli and Salmonella ...

    African Journals Online (AJOL)

    Pathogenic Escherichia coli and Salmonella species are the causative agents of various disease complexes in poultry such as colibacillosis, fowl typhoid, pullorum disease and salmonellosis. Some strains of E. coli and Salmonella spp. have been shown to be resistant to multiple antibiotics. We carried out a bacteriological ...

  9. Glucuronidase activity of Escherichia coli isolated from chicken carcasses

    OpenAIRE

    Perin,Luana Martins; Yamazi,Anderson Keizo; Moraes,Paula Mendonça; Cossi,Marcus Vinícius Coutinho; Pinto,Paulo Sérgio de Arruda; Nero,Luís Augusto

    2010-01-01

    To identify Escherichia coli through the production of β-D-glucuronidase (GUD), 622 suspect cultures were isolated from chicken carcasses and plated in PetrifilmTM EC. Of these cultures, only 44 (7.1%) failed to produce GUD. This result indicates the usefulness of GUD production for estimating E. coli populations in chicken.

  10. ANTIBACTERIAL ACTIVITY OF FRUIT AN Against Escherichia coli ...

    African Journals Online (AJOL)

    userpc

    ABSTRACT. The preliminary antibacterial activity of f evaluated against Escherichia coli and S method. The bioactive components of the aqueous, ethanol and acetone solvents. The effective at different concentrations of 6. ranging between 6.0±2.5mm-20.0±4.5mm f coli. Aqueous extract at 6.25mg/ml.

  11. Expression of green fluorescent protein (GFPuv) in Escherichia coli ...

    African Journals Online (AJOL)

    The recombinant green fluorescent protein (GFPuv) was expressed by transformed cells of Escherichia coli DH5-α grown in LB/amp broth at 37oC, for 8 h and 24 h. To evaluate the effectiveness of different parameters to improve the expression of GFPuv by E. coli, four variable culturing conditions were set up for assays by ...

  12. Effect of high pressurized carbon dioxide on Escherichia coli ...

    African Journals Online (AJOL)

    Carbon dioxide at high pressure can retard microbial growth and sometimes kill microorganisms depending on values of applied pressure, temperature and exposure time. In this study the effect of high pressurised carbon dioxide (HPCD) on Escherichia coli was investigated. Culture of E. coli was subjected to high ...

  13. Adsorption of Escherichia coli Using Bone Char | Rezaee | Journal ...

    African Journals Online (AJOL)

    The aim of study was providing a novel adsorbent for the removal of Escherichia coli (E.coli) as a microbial model from contaminated air especially in hospital units using bone char (BC). The BC was prepared from cattle animal bone by pyrolysis in a furnace at 450°C for 2 h. The characteristics of BC have been determined ...

  14. Antimicrobial resistance of non-clinical Escherichia coli strains from ...

    African Journals Online (AJOL)

    This study was carried out to determine resistance profiles of Escherichia coli strains isolated from clinically healthy chickens in Nsukka, southeast Nigeria. A total of 324 E. coli strains isolated from cloaca swabs from 390 chickens were tested against 16 antimicrobial agents using the disc diffusion method. The antibiotics ...

  15. Prevalence of Aeromonas species and Escherichia coli in stool ...

    African Journals Online (AJOL)

    Background: Diarrhoea is one of the main causes of mortality and morbidity in childhood. Bacterial diarrhoea is a common disorder. Aeromonas species and Escherichia coli (E. coli) are some of the aetiological agents associated with diarrhoea in children. Objective: To determine the prevalence of Aeromonas species and ...

  16. Growth responses of Escherichia coli and Myxococcus xanthus on ...

    African Journals Online (AJOL)

    We investigated the growth kinetics of wild-type Escherichia coli, non-motile E. coli, and Myxococcus xanthus, cultured on semi-solid agar substrates containing different amounts of nutrient and agar. We found that substrate stiffness, which was controlled by agar concentration, modulates the growth of motile bacteria, such ...

  17. Antimicrobial susceptibilities of avian Escherichia coli isolates in ...

    African Journals Online (AJOL)

    Yomi

    2012-03-06

    Mar 6, 2012 ... Colibacillosis is a poultry disease of economic importance in Iran and all around the world. The aim of this study is to test the antibiotic sensitivity of Escherichia coli strains which were isolated in Tabriz. A total of 100 E. coli strains isolated from avian colibacillosis of 50 farms from 2008 to 2009 in Tabriz,.

  18. Growth modeling of uropathogenic Escherichia coli in ground chicken meat

    Science.gov (United States)

    Extraintestinal Pathogenic Escherichia coli (ExPEC), including Uropathogenic E. coli (UPEC), are common contaminants in poultry meat, and are a major pathogen associated with inflammatory bowel disease, ulcerative colitis, sepsis, and urinary tract infections. The purpose of this study was to determ...

  19. Screening of verotoxin-producing Escherichia coli (VETC) O104 ...

    African Journals Online (AJOL)

    Escherichia coli strains are important causes of diarrheal disease in the world and remain a major public health problem of animals and human. Sixty seven samples from different kind of food, water, soil and composit were screened for the detection of verotoxin-producing E.coli (VTEC) in the Egyptian markets from different ...

  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

    -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...

  1. Prevalence of Antibiotic-Resistant Strains of Escherichia coli in ...

    African Journals Online (AJOL)

    A measured Escherichia coli level in drinking water is perhaps the most popular means of determining human health risks globally. Water samples from wells, boreholes and sachet water, the 3 predominant sources of drinking water in the study area were evaluated for the presence of bacteria, particularly E coli. Bacteria ...

  2. Antimicrobial susceptibilities of avian Escherichia coli isolates in ...

    African Journals Online (AJOL)

    Colibacillosis is a poultry disease of economic importance in Iran and all around the world. The aim of this study is to test the antibiotic sensitivity of Escherichia coli strains which were isolated in Tabriz. A total of 100 E. coli strains isolated from avian colibacillosis of 50 farms from 2008 to 2009 in Tabriz, were investigated for ...

  3. Enterotoxigenic Escherichia coli multilocus sequence types in Guatemala and Mexico.

    Science.gov (United States)

    Nicklasson, Matilda; Klena, John; Rodas, Claudia; Bourgeois, August Louis; Torres, Olga; Svennerholm, Ann Mari; Sjoling, Asa

    2010-01-01

    The genetic backgrounds of 24 enterotoxigenic Escherichia coli (ETEC) strains from Mexico and Guatemala expressing heat-stable toxin (ST) and coli surface antigen 6 (CS6) were analyzed. US travelers to these countries and resident children in Guatemala were infected by ETEC strains of sequence type 398, expressing STp and carrying genetically identical CS6 sequences.

  4. Enterotoxigenic Escherichia coli Multilocus Sequence Types in Guatemala and Mexico

    OpenAIRE

    Nicklasson, Matilda; Klena, John; Rodas, Claudia; Bourgeois, August Louis; Torres, Olga; Svennerholm, Ann-Mari; Sj?ling, ?sa

    2010-01-01

    The genetic backgrounds of 24 enterotoxigenic Escherichia coli (ETEC) strains from Mexico and Guatemala expressing heat-stable toxin (ST) and coli surface antigen 6 (CS6) were analyzed. US travelers to these countries and resident children in Guatemala were infected by ETEC strains of sequence type 398, expressing STp and carrying genetically identical CS6 sequences.

  5. Septicemia caused by cysteine-dependent Escherichia coli.

    OpenAIRE

    Yuen, K Y; Seto, W H; Tsui, K H; Hui, W T

    1990-01-01

    A case of septicemia and urinary tract infection caused by cysteine-dependent Escherichia coli in a 70-year-old woman with bilateral staghorn calculi is described. This is the second report of a cysteine-dependent E. coli bacteremia. The bacterium was falsely susceptible to ampicillin and co-trimoxazole when tested on a medium without cysteine supplement.

  6. Purification and light-scattering analysis of penicillin-binding protein 4 from Escherichia coli

    NARCIS (Netherlands)

    Fusetti, F; Dijkstra, BW

    1996-01-01

    Penicillin binding protein 4 (PBP4) from Escherichia coli is a protein involved in the recycling and maturation of the bacterial cell wall and it is inhibited by beta-lactam antibiotics, PBP4 exhibits D-Ala-D-Ala-endopeptidase as well as D-Ala-D-Ala-carboxypeptidase activity. To provide a structural

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

    Science.gov (United States)

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

    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 sought to determine if other E. coli pathogens use a similar strategy. We found that uropathogenic E. coli CFT073 and enteropathogenic E. coli E2348/69 occupy intestinal niches that are distinct from that of E. coli EDL933. In contrast, two enterohemorrhagic strains, E. coli EDL933 and E. coli Sakai, occupy the same niche, suggesting that strategies to prevent colonization by a given pathotype should be effective against other strains of the same pathotype. However, we found that a combination of commensal E. coli strains that can prevent colonization by E. coli EDL933 did not prevent colonization by E. coli CFT073 or E. coli E2348/69. Our results indicate that development of probiotics to target multiple E. coli pathotypes will be problematic, as the factors that govern niche occupation and hence stable colonization vary significantly among strains. PMID:24566621

  8. Predicting Escherichia coli's chemotactic drift under exponential gradient

    Science.gov (United States)

    Samanta, Sibendu; Layek, Ritwik; Kar, Shantimoy; Raj, M. Kiran; Mukhopadhyay, Sudipta; Chakraborty, Suman

    2017-09-01

    Bacterial species are known to show chemotaxis, i.e., the directed motions in the presence of certain chemicals, whereas the motion is random in the absence of those chemicals. The bacteria modulate their run time to induce chemotactic drift towards the attractant chemicals and away from the repellent chemicals. However, the existing theoretical knowledge does not exhibit a proper match with experimental validation, and hence there is a need for developing alternate models and validating experimentally. In this paper a more robust theoretical model is proposed to investigate chemotactic drift of peritrichous Escherichia coli under an exponential nutrient gradient. An exponential gradient is used to understand the steady state behavior of drift because of the logarithmic functionality of the chemosensory receptors. Our theoretical estimations are validated through the experimentation and simulation results. Thus, the developed model successfully delineates the run time, run trajectory, and drift velocity as measured from the experiments.

  9. 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.

  10. Expression of a soluble truncated Vargula luciferase in Escherichia coli.

    Science.gov (United States)

    Hunt, Eric A; Moutsiopoulou, Angeliki; Broyles, David; Head, Trajen; Dikici, Emre; Daunert, Sylvia; Deo, Sapna K

    2017-04-01

    Marine luciferases are regularly employed as useful reporter molecules across a range of various applications. However, attempts to transition expression from their native eukaryotic environment into a more economical prokaryotic, i.e. bacterial, expression system often presents several challenges. Specifically, bacterial protein expression inherently lacks chaperone proteins to aid in the folding process, while Escherichia coli presents a reducing cytoplasmic environment in. These conditions contribute to the inhibition of proper folding of cysteine-rich proteins, leading to incorrect tertiary structure and ultimately inactive and potentially insoluble protein. Vargula luciferase (Vluc) is a cysteine-rich marine luciferase that exhibits glow-type bioluminescence through a reaction between its unique native substrate and molecular oxygen. Because most other commonly used bioluminescent proteins exhibit flash-type emission kinetics, this emission characteristic of Vluc is desirable for high-throughput applications where stability of emission is required for the duration of data collection. A truncated form of Vluc that retains considerable bioluminescence activity (55%) compared to the native full-length protein has been reported in the literature. However, expression and purification of this luciferase from bacterial systems has proven difficult. Herein, we demonstrate the expression and purification of a truncated form of Vluc from E. coli. This truncated Vluc (tVluc) was subsequently characterized in terms of both its biophysical and bioluminescence properties. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Elimination of Escherichia coli and Salmonella in Clam by Using Zeolite in a Station of Depuration.

    Science.gov (United States)

    Gdoura, Morsi; Sellami, Hanen; Khannous, Lamia; Ketata, Najib; Neila, Idriss Ben; Traore, Al Ibrahim; Chekir, Zouhair; Gdoura, Radhouane

    2017-09-01

      The application of natural zeolite for water and wastewater treatment has been carried out and is still a promising technique in environmental cleaning processes. Natural zeolite can be used to improve the purification process of clams (Ruditapes decussatus). Thus, our study aimed at improving the clam purification system in order to reduce Escherichia coli and eliminate Salmonella in samples artificially contaminated with this bacterium using a natural zeolite to replace the biological filter. The results showed that zeolite used in a depuration system improved the clam purification process. Moreover, natural zeolite exhibited high performance in the adsorption of bacteria and allowed to reduce the Escherichia coli abundance in 24 h, thus ensuring purified clams conformity with the ISO 16649-3 standard. These results indicate the beneficial effects of using zeolite in the adsorption of bacteria and the reduction in the abundance of Escherichia coli and set the Salmonella from marine organisms.

  12. Multiplex polymerase chain reaction for identification of Escherichia coli, Escherichia albertii and Escherichia fergusonii.

    Science.gov (United States)

    Lindsey, Rebecca L; Garcia-Toledo, L; Fasulo, D; Gladney, L M; Strockbine, N

    2017-09-01

    Escherichia coli, Escherichia albertii, and Escherichia fergusonii are closely related bacteria that can cause illness in humans, such as bacteremia, urinary tract infections and diarrhea. Current identification strategies for these three species vary in complexity and typically rely on the use of multiple phenotypic and genetic tests. To facilitate their rapid identification, we developed a multiplex PCR assay targeting conserved, species-specific genes. We used the Daydreamer™ (Pattern Genomics, USA) software platform to concurrently analyze whole genome sequence assemblies (WGS) from 150 Enterobacteriaceae genomes (107 E. coli, 5 Shigella spp., 21 E. albertii, 12 E. fergusonii and 5 other species) and design primers for the following species-specific regions: a 212bp region of the cyclic di-GMP regulator gene (cdgR, AW869_22935 from genome K-12 MG1655, CP014225) for E. coli/Shigella; a 393bp region of the DNA-binding transcriptional activator of cysteine biosynthesis gene (EAKF1_ch4033 from genome KF1, CP007025) for E. albertii; and a 575bp region of the palmitoleoyl-acyl carrier protein (ACP)-dependent acyltransferase (EFER_0790 from genome ATCC 35469, CU928158) for E. fergusonii. We incorporated the species-specific primers into a conventional multiplex PCR assay and assessed its performance with a collection of 97 Enterobacteriaceae strains. The assay was 100% sensitive and specific for detecting the expected species and offers a quick and accurate strategy for identifying E. coli, E. albertii, and E. fergusonii in either a single reaction or by in silico PCR with sequence assemblies. Published by Elsevier B.V.

  13. Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam

    NARCIS (Netherlands)

    Trung, Nguyen Vinh; Nhung, Hoang Ngoc; Carrique-Mas, Juan J.; Mai, Ho Huynh; Tuyen, Ha Thanh; Campbell, James; Nhung, Nguyen Thi; van Minh, Pham; Wagenaar, Jaap A.; Mai, Nguyen Thi Nhu; Hieu, Thai Quoc; Schultsz, Constance; Hoa, Ngo Thi

    2016-01-01

    Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an outbreak of E.

  14. Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam

    NARCIS (Netherlands)

    Trung, Nguyen Vinh; Nhung, Hoang Ngoc; Carrique-Mas, Juan J.; Mai, Ho Huynh; Tuyen, Ha Thanh; Campbell, James; Nhung, Nguyen Thi; Minh, Van Pham; Wagenaar, Jaap A.; Mai, Nguyen Thi Nhu; Hieu, Thai Quoc; Schultsz, Constance; Hoa, Ngo Thi

    2016-01-01

    Background: Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an

  15. Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam

    NARCIS (Netherlands)

    Trung, Nguyen Vinh; Nhung, Hoang Ngoc; Carrique-Mas, Juan J; Mai, Ho Huynh; Tuyen, Ha Thanh; Campbell, James; Nhung, Nguyen Thi; Van Minh, Pham; Wagenaar, Jaap A; Mai, Nguyen Thi Nhu; Hieu, Thai Quoc; Schultsz, Constance; Hoa, Ngo Thi

    2016-01-01

    BACKGROUND: Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an

  16. Sequence periodicity of Escherichia coli is concentrated in intergenic regions

    Directory of Open Access Journals (Sweden)

    Trifonov Edward N

    2004-08-01

    Full Text Available Abstract Background Sequence periodicity with a period close to the DNA helical repeat is a very basic genomic property. This genomic feature was demonstrated for many prokaryotic genomes. The Escherichia coli sequences display the period close to 11 base pairs. Results Here we demonstrate that practically only ApA/TpT dinucleotides contribute to overall dinucleotide periodicity in Escherichia coli. The noncoding sequences reveal this periodicity much more prominently compared to protein-coding sequences. The sequence periodicity of ApC/GpT, ApT and GpC dinucleotides along the Escherichia coli K-12 is found to be located as well mainly within the intergenic regions. Conclusions The observed concentration of the dinucleotide sequence periodicity in the intergenic regions of E. coli suggests that the periodicity is a typical property of prokaryotic intergenic regions. We suppose that this preferential distribution of dinucleotide periodicity serves many biological functions; first of all, the regulation of transcription.

  17. 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

  18. Specific electromagnetic effects of microwave radiation on Escherichia coli.

    Science.gov (United States)

    Shamis, Yury; Taube, Alex; Mitik-Dineva, Natasa; Croft, Rodney; Crawford, Russell J; Ivanova, Elena P

    2011-05-01

    The present study investigated the effects of microwave (MW) radiation applied under a sublethal temperature on Escherichia coli. The experiments were conducted at a frequency of 18 GHz and at a temperature below 40°C to avoid the thermal degradation of bacterial cells during exposure. The absorbed power was calculated to be 1,500 kW/m(3), and the electric field was determined to be 300 V/m. Both values were theoretically confirmed using CST Microwave Studio 3D Electromagnetic Simulation Software. As a negative control, E. coli cells were also thermally heated to temperatures up to 40°C using Peltier plate heating. Scanning electron microscopy (SEM) analysis performed immediately after MW exposure revealed that the E. coli cells exhibited a cell morphology significantly different from that of the negative controls. This MW effect, however, appeared to be temporary, as following a further 10-min elapsed period, the cell morphology appeared to revert to a state that was identical to that of the untreated controls. Confocal laser scanning microscopy (CLSM) revealed that fluorescein isothiocyanate (FITC)-conjugated dextran (150 kDa) was taken up by the MW-treated cells, suggesting that pores had formed within the cell membrane. Cell viability experiments revealed that the MW treatment was not bactericidal, since 88% of the cells were recovered after radiation. It is proposed that one of the effects of exposing E. coli cells to MW radiation under sublethal temperature conditions is that the cell surface undergoes a modification that is electrokinetic in nature, resulting in a reversible MW-induced poration of the cell membrane.

  19. Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli

    DEFF Research Database (Denmark)

    Jørgensen, Steffen L; Kudirkiene, Egle; Li, Lili

    2017-01-01

    Escherichia coli causing infection outside the gastrointestinal system are referred to as extra-intestinal pathogenic E. coli. Avian pathogenic E. coli is a subgroup of extra-intestinal pathogenic E. coli and infections due to avian pathogenic E. coli have major impact on poultry production economy...... sequences, 12 predicated genomic islands, three prophage-related sequences, and two clustered regularly interspaced short palindromic repeats regions on the chromosome, suggesting the possible occurrence of horizontal gene transfer in this strain. The wildtype strain of E. coli APEC_O2 is resistant towards...

  20. Environmental Escherichia coli: Ecology and public health implications - A review

    Science.gov (United States)

    Jang, Jeonghwan; Hur, Hor-Gil; Sadowsky, Michael J.; Byappanahalli, Muruleedhara; Yan, Tao; Ishii, Satoshi

    2017-01-01

    Escherichia coli is classified as a rod-shaped, Gram-negative bacterium in the family Enterobacteriaceae. The bacterium mainly inhabits the lower intestinal tract of warm-blooded animals, including humans, and is often discharged into the environment through feces or wastewater effluent. The presence of E. coli in environmental waters has long been considered as an indicator of recent fecal pollution. However, numerous recent studies have reported that some specific strains of E. coli can survive for long periods of time, and potentially reproduce, in extra-intestinal environments. This indicates that E. coli can be integrated into indigenous microbial communities in the environment. This naturalization phenomenon calls into question the reliability of E. coli as a fecal indicator bacterium (FIB). Recently, many studies reported that E. coli populations in the environment are affected by ambient environmental conditions affecting their long-term survival. Large-scale studies of population genetics provide the diversity and complexity of E. coli strains in various environments, affected by multiple environmental factors. This review examines the current knowledge on the ecology of E. coli strains in various environments in regards to its role as a FIB and as a naturalized member of indigenous microbial communities. Special emphasis is given on the growth of pathogenic E. coli in the environment, and the population genetics of environmental members of the genus Escherichia. The impact of environmental E. coli on water quality and public health is also discussed.

  1. Current pathogenic Escherichia coli foodborne outbreak cases and therapy development.

    Science.gov (United States)

    Yang, Shih-Chun; Lin, Chih-Hung; Aljuffali, Ibrahim A; Fang, Jia-You

    2017-08-01

    Food contamination by pathogenic microorganisms has been a serious public health problem and a cause of huge economic losses worldwide. Foodborne pathogenic Escherichia coli (E. coli) contamination, such as that with E. coli O157 and O104, is very common, even in developed countries. Bacterial contamination may occur during any of the steps in the farm-to-table continuum from environmental, animal, or human sources and cause foodborne illness. To understand the causes of the foodborne outbreaks by E. coli and food-contamination prevention measures, we collected and investigated the past 10 years' worldwide reports of foodborne E. coli contamination cases. In the first half of this review article, we introduce the infection and symptoms of five major foodborne diarrheagenic E. coli pathotypes: enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli/enterohemorrhagic E. coli (STEC/EHEC), Shigella/enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), and enterotoxigenic E. coli (ETEC). In the second half of this review article, we introduce the foodborne outbreak cases caused by E. coli in natural foods and food products. Finally, we discuss current developments that can be applied to control and prevent bacterial food contamination.

  2. Mechanism of Sperm Immobilization by Escherichia coli

    Directory of Open Access Journals (Sweden)

    Vijay Prabha

    2010-01-01

    Conclusion. In conclusion, these results have shown immobilization of spermatozoa by E. coli and demonstrate a factor (SIF produced and secreted by E. coli which causes variable structural damage as probable morphological correlates of immobilization.

  3. Serogroups of Escherichia coli from drinking water.

    Science.gov (United States)

    Ramteke, P W; Tewari, Suman

    2007-07-01

    Fifty seven isolates of thermotolerant E. coli were recovered from 188 drinking water sources, 45 (78.9%) were typable of which 15 (26.3%) were pathogenic serotypes. Pathogenic serogroup obtained were 04 (Uropathogenic E. coli, UPEC), 025 (Enterotoxigenic E. coli, ETEC), 086 (Enteropathogenic E. coli, EPEC), 0103 (Shiga-toxin producing E. coli, STEC), 0157 (Shiga-toxin producing E. coli, STEC), 08 (Enterotoxigenic E. coli, ETEC) and 0113 (Shiga-toxin producing E. coli, STEC). All the pathogenic serotypes showed resistance to bacitracin and multiple heavy metal ions. Resistance to streptomycin and cotrimazole was detected in two strains whereas resistance to cephaloridine, polymixin-B and ampicillin was detected in one strain each. Transfer of resistances to drugs and metallic ions was observed in 9 out of 12 strains studied. Resistances to bacitracin were transferred in all nine strains. Among heavy metals resistance to As(3+) followed by Cr(6+) were transferred more frequently.

  4. 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-dwelling human...

  5. Rapid Sterilization of Escherichia coli by Solution Plasma Process

    Science.gov (United States)

    Andreeva, Nina; Ishizaki, Takahiro; Baroch, Pavel; Saito, Nagahiro

    2012-12-01

    Solution plasma (SP), which is a discharge in the liquid phase, has the potential for rapid sterilization of water without chemical agents. The discharge showed a strong sterilization performance against Escherichia coli bacteria. The decimal value (D value) of the reduction time for E. coli by this system with an electrode distance of 1.0 mm was estimated to be approximately 1.0 min. Our discharge system in the liquid phase caused no physical damage to the E. coli and only a small increase in the temperature of the aqueous solution. The UV light generated by the discharge was an important factor in the sterilization of E. coli.

  6. Human Meningitis-Associated Escherichia coli

    Science.gov (United States)

    KIM, KWANG SIK

    2016-01-01

    E. coli is the most common Gram-negative bacillary organism causing meningitis and E. coli meningitis continues to be an important cause of mortality and morbidity throughout the world. Our incomplete knowledge of its pathogenesis contributes to such mortality and morbidity. Recent reports of E. coli strains producing CTX-M-type or TEM-type extended-spectrum β-lactamases create a challenge. Studies using in vitro and in vivo models of the blood-brain barrier have shown that E. coli meningitis follows a high-degree of bacteremia and invasion of the blood-brain barrier. E. coli invasion of the blood-brain barrier, the essentials step in the development of E. coli meningitis, requires specific microbial and host factors as well as microbe- and host-specific signaling molecules. Blockade of such microbial and host factors contributing to E. coli invasion of the blood-brain barrier is shown to be efficient in preventing E. coli penetration into the brain. The basis for requiring a high-degree of bacteremia for E. coli penetration of the blood-brain barrier, however, remains unclear. Continued investigation on the microbial and host factors contributing to a high-degree of bacteremia and E. coli invasion of the blood-brain barrier is likely to identify new targets for prevention and therapy of E. coli meningitis. PMID:27223820

  7. Dissecting Escherichia coli outer membrane biogenesis using differential proteomics.

    Directory of Open Access Journals (Sweden)

    Alessandra M Martorana

    Full Text Available The cell envelope of Gram-negative bacteria is a complex multi-layered structure comprising an inner cytoplasmic membrane and an additional asymmetric lipid bilayer, the outer membrane, which functions as a selective permeability barrier and is essential for viability. Lipopolysaccharide, an essential glycolipid located in the outer leaflet of the outer membrane, greatly contributes to the peculiar properties exhibited by the outer membrane. This complex molecule is transported to the cell surface by a molecular machine composed of seven essential proteins LptABCDEFG that form a transenvelope complex and function as a single device. While advances in understanding the mechanisms that govern the biogenesis of the cell envelope have been recently made, only few studies are available on how bacterial cells respond to severe envelope biogenesis defects on a global scale. Here we report the use of differential proteomics based on Multidimensional Protein Identification Technology (MudPIT to investigate how Escherichia coli cells respond to a block of lipopolysaccharide transport to the outer membrane. We analysed the envelope proteome of a lptC conditional mutant grown under permissive and non permissive conditions and identified 123 proteins whose level is modulated upon LptC depletion. Most such proteins belong to pathways implicated in cell envelope biogenesis, peptidoglycan remodelling, cell division and protein folding. Overall these data contribute to our understanding on how E. coli cells respond to LPS transport defects to restore outer membrane functionality.

  8. The Biology of the Escherichia coli Extracellular Matrix

    Science.gov (United States)

    Hufnagel, David A.; DePas, William H.; Chapman, Matthew R.

    2015-01-01

    Chapter Summary Escherichia coli (E. coli) is one of the world’s best-characterized organisms, as it has been extensively studied for over a century. However, most of this work has focused on E. coli grown under laboratory conditions that do not faithfully simulate its natural environments. Therefore, the historical perspectives on E. coli physiology and life cycle are somewhat skewed toward experimental systems that feature E. coli growing logarithmically in a test tube. Typically a commensal bacterium, E. coli resides in the lower intestines of a slew of animals. Outside of the lower intestine, E. coli can adapt and survive in a very different set of environmental conditions. Biofilm formation allows E. coli to survive, and even thrive, in environments that do not support the growth of planktonic populations. E. coli can form biofilms virtually everywhere; in the bladder during a urinary tract infection, on in-dwelling medical devices, and outside of the host on plants and in the soil. The E. coli extracellular matrix, primarily composed of the protein polymer named curli and the polysaccharide cellulose, promotes adherence to organic and inorganic surfaces, and resistance to desiccation, the host immune system and other antimicrobials. The pathways that govern E. coli biofilm formation, cellulose production, and curli biogenesis will be discussed in this book chapter, which concludes with insights into the future of E. coli biofilm research and potential therapies. PMID:26185090

  9. Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam

    OpenAIRE

    Trung, Nguyen Vinh; Nhung, Hoang Ngoc; Carrique-Mas, Juan J.; Mai, Ho Huynh; Tuyen, Ha Thanh; Campbell, James; Nhung, Nguyen Thi; Van Minh, Pham; Wagenaar, Jaap A.; Mai, Nguyen Thi Nhu; Hieu, Thai Quoc; Schultsz, Constance; Hoa, Ngo Thi

    2016-01-01

    Background Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an outbreak of E. coli O104:H4 in Europe in 2011. We assessed the opportunities for E. coli carrying the aggR and stx genes to emerge in ?backyard? farms in south-east Asia. Results Faecal samples collected...

  10. Carumonam enhances reactivity of Escherichia coli with mono- and polyclonal antisera to rough Escherichia coli J5.

    OpenAIRE

    Overbeek, B P; Schellekens, J F; Lippe, W; Dekker, B A; Verhoef, J

    1987-01-01

    Escherichia coli O111 reacts only slightly with antiserum to its rough mutant E. coli J5 in an enzyme-linked immunosorbent assay. When E. coli O111 was grown in the presence of sub-MICs of the monocyclic beta-lactam antibiotic carumonam, however, the enzyme-linked immunosorbent assay titer increased from 1,280 to 81,920. When the bacteria were grown in the presence of carumonam, the titer that was obtained with antiserum against E. coli O111 was not affected. This reaction was abolished after...

  11. Definition of Additional Flagellar Genes in ESCHERICHIA COLI K12

    OpenAIRE

    Komeda, Yoshibumi; Kutsukake, Kazuhiro; Iino, Tetsuo

    1980-01-01

    Twenty-nine flagellar genes in Escherichia coli K12 have previously been assigned to three regions of the genome. Flagellar region I is located between pyrC and ptsG, region II between aroD and uvrC, and region III between uvrC and his. In this study, flagellar mutants in Escherichia coli K12 were obtained by selection for resistance to the flagellotropic phage, χ. They were analyzed in complementation tests using P1 phage-mediated transduction. In addition to the fla genes already described,...

  12. Obscured phylogeny and possible recombinational dormancy in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Sawyer Stanley A

    2011-06-01

    Full Text Available Abstract Background Escherichia coli is one of the best studied organisms in all of biology, but its phylogenetic structure has been difficult to resolve with current data and analytical techniques. We analyzed single nucleotide polymorphisms in chromosomes of representative strains to reconstruct the topology of its emergence. Results The phylogeny of E. coli varies according to the segment of chromosome analyzed. Recombination between extant E. coli groups is largely limited to only three intergroup pairings. Conclusions Segment-dependent phylogenies most likely are legacies of a complex recombination history. However, E. coli are now in an epoch in which they no longer broadly share DNA. Using the definition of species as organisms that freely exchange genetic material, this recombinational dormancy could reflect either the end of E. coli as a species, or herald the coalescence of E. coli groups into new species.

  13. 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...... of redox and energy metabolism and should help in developing metabolic engineering strategies in E. coli....

  14. Engineering Escherichia coli for autoinducible production of n-butanol

    OpenAIRE

    Qinglong Wang; Yi ding; Li Liu; Jiping Shi; Junsong Sun; Yongchang Xue

    2015-01-01

    Background: Escherichia coli does not produce n-butanol naturally, but can be butanologenic when related enzymes were expressed using inducible elements on plasmids. In this study we attempted to confer E. coli strain capability of automatic excretion of the chemical by employing a native anaerobic promoter. Also, a novel DNA kit was designed for PCR preparation of linear DNA fragments to perform strain modification. The kit is primarily composed of two mother vectors, co-transformation of li...

  15. 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....

  16. Genotypic Characterization of Egypt Enterotoxigenic Escherichia coli Isolates Expressing Coli Surface Antigen 6

    Science.gov (United States)

    2013-02-01

    USA Abstract Introduction: One approach to control enterotoxigenic Escherichia coli (ETEC) infections has been to develop vaccines focused on...results show a lack of clonality among Egypt CS6 E. coli isolates and supports the use and the further research on vaccines targeting this cell surface...organisms must colonize the mucosal epithelium; this process utilizes fimbrial and non-fimbrial colonization factors, also referred to as coli surface

  17. antimicrobial susceptibility and plasmids from escherichia coli

    African Journals Online (AJOL)

    2001-10-02

    Oct 2, 2001 ... shown to occur among different animal species, between humans, and from animals to humans and vice versa(5,6). Antibiotic resistant E. coli may be passed from animals to humans through contact with faecal material or faecally contaminated food sources. Normal E. coli flora acquire resistance plasmids ...

  18. Characterization of Escherichia coli Phylogenetic Groups ...

    African Journals Online (AJOL)

    infection, and neonatal meningitis.[1] Phylogenetic analysis has shown that E. coli strains fall into four main groups. (A, B1, B2, and D). It has been found that pathogenic E. coli strains causing extraintestinal infections mainly belong to group B2 and a lesser extent to group D whereas commensal strains belong to group A ...

  19. ANTIMICIROBIAL SUSCEPTIBILITY PATTERNS OF Escherichia coli ...

    African Journals Online (AJOL)

    DR. AMINU

    ABSTRACT. A total of 56 and 24 strains of E. coli and Shigella sp. isolated from children less than five years with diarrhoea attending 3 different hospitals in South South Nigeria were screened for their antibiotic resistance patterns. Approximately 80% of E. coli and 70% of Shigella isolates were resistant to tetracycline.

  20. Biochemical and serological characterization of Escherichia coli ...

    African Journals Online (AJOL)

    This study was designed to determine the isolation rate, serotypes and biochemical profiles of E. coli from colibacillosis and dead-in-shell embryos in Zaria, Northern-Nigeria. The isolation rate of E. coli from hatcheries studied were 4.67% and 7.50% from farms of Simtu Agricultural Company and National Animal Production ...

  1. X-ray microtomographic visualization of Escherichia coli by metalloprotein overexpression

    CERN Document Server

    Mizutani, Ryuta; Ohtsuka, Masato; Kimura, Minoru; Takeuchi, Akihisa; Uesugi, Kentaro; Suzuki, Yoshio

    2016-01-01

    This paper reports X-ray microtomographic visualization of the microorganism Escherichia coli overexpressing a metalloprotein ferritin. The three-dimensional distribution of linear absorption coefficients determined using a synchrotron radiation microtomograph with a simple projection geometry revealed that the X-ray absorption was homogeneously distributed, suggesting that every E. coli cell was labeled with the ferritin. The ferritin-expressing E. coli exhibited linear absorption coefficients comparable to those of phosphotungstic-acid stained cells. The submicrometer structure of the ferritin-expressing E. coli cells was visualized by Zernike phase contrast using an imaging microtomograph equipped with a Fresnel zone plate. The obtained images revealed curved columnar or bunching oval structures corresponding to the E. coli cells. These results indicate that the metalloprotein overexpression facilitates X-ray visualization of three-dimensional cellular structures of biological objects.

  2. Shigella strains are not clones of Escherichia coli but sister species in the genus Escherichia.

    Science.gov (United States)

    Zuo, Guanghong; Xu, Zhao; Hao, Bailin

    2013-02-01

    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. In view of the overall success and high resolution power of the CVTree approach, this result should be taken seriously. We hope that the present report may promote further in-depth study of the Shigella-E. coli relationship. Copyright © 2013. Production and hosting by Elsevier Ltd.

  3. 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.

  4. 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.

  5. Synthesis of rosmarinic acid analogues in Escherichia coli.

    Science.gov (United States)

    Zhuang, Yibin; Jiang, Jingjie; Bi, Huiping; Yin, Hua; Liu, Shaowei; Liu, Tao

    2016-04-01

    To produce rosmarinic acid analogues in the recombinant Escherichia coli BLRA1, harboring a 4-coumarate: CoA ligase from Arabidopsis thaliana (At4CL) and a rosmarinic acid synthase from Coleus blumei (CbRAS). Incubation of the recombinant E. coli strain BLRA1 with exogenously supplied phenyllactic acid (PL) and analogues as acceptor substrates, and coumaric acid and analogues as donor substrates led to production of 18 compounds, including 13 unnatural RA analogues. This work demonstrates the viability of synthesizing a broad range of rosmarinic acid analogues in E. coli, and sheds new light on the substrate specificity of CbRAS.

  6. Spontaneous Escherichia coli Meningitis Associated with Hemophagocytic Lymphohistiocytosis

    Directory of Open Access Journals (Sweden)

    Kuo-Hsuan Chang

    2006-01-01

    Full Text Available Spontaneous Escherichia coli meningitis has not been previously reported in association with hemophago-cytic lymphohistiocytosis (HLH. A previously healthy 72-year-old woman was admitted due to fever, nuchal rigidity, disturbed consciousness and splenomegaly. Anemia, thrombocytopenia and hyperfer-ritinemia developed on the 8th day of hospitalization. Cultures of cerebrospinal fluid and blood grew E. coli. Abundant macrophages overwhelmed erythrocytes in the bone marrow aspirate, confirming the presence of hemophagocytosis. E. coli meningitis was managed with a 40-day course of antibiotic treatment. However, the severity of anemia and thrombocytopenia progressed despite intensive transfusion therapy. The patient died of HLH on the 60th day of hospitalization.

  7. Experimental Escherichia coli O157:H7 carriage in calves.

    OpenAIRE

    Brown, C A; Harmon, B G; Zhao, T; Doyle, M P

    1997-01-01

    Nine weaned calves (6 to 8 weeks of age) were given 10(10) CFU of a five-strain mixture of enterohemorrhagic Escherichia coli O157:H7 by oral-gastric intubation. After an initial brief period of pyrexia in three calves and transient mild diarrhea in five calves, calves were clinically normal throughout the 13- to 27-day study. The population of E. coli O157:H7 in the faces decreased dramatically in all calves during the first 2 weeks after inoculation. Thereafter, small populations of E. coli...

  8. Escherichia coli is naturally transformable in a novel transformation system.

    Science.gov (United States)

    Sun, Dongchang; Zhang, Yanmei; Mei, Yunjun; Jiang, Hui; Xie, Zhixiong; Liu, Huihui; Chen, Xiangdong; Shen, Ping

    2006-12-01

    A novel transformation system, in which neither a nonphysiological concentration of Ca2+ and temperature shifts nor electronic shocks were required, was developed to determine whether Escherichia coli is naturally transformable. In the new protocol, E. coli was cultured normally to the stationary phase and then cultured statically at 37 degrees C in Luria-Bertani broth. After static culture, transformation occurred in bacteria spread on Luria-Bertani plates. The protein synthesis inhibitor chloramphenicol inhibited this transformation process. The need for protein synthesis in plated bacteria suggests that the transformation of E. coli in this new system is regulated physiologically.

  9. Enhanced gentamicin killing of Escherichia coli by tet gene expression.

    OpenAIRE

    Merlin, T L; Corvo, D L; Gill, J H; Griffith, J K

    1989-01-01

    Time-kill studies were performed to determine the effect of tetracycline resistance (tet) gene expression on gentamicin killing of Escherichia coli. Expression of tet increased gentamicin killing in laboratory strains and clinical isolates. A role for tetracycline in inducing tet expression and increasing the bactericidal activity of aminoglycosides is suggested.

  10. Expression and purification of recombinant hemoglobin in Escherichia coli

    DEFF Research Database (Denmark)

    Natarajan, Chandrasekhar; Jiang, Xiaoben; Fago, Angela

    2011-01-01

    BACKGROUND: Recombinant DNA technologies have played a pivotal role in the elucidation of structure-function relationships in hemoglobin (Hb) and other globin proteins. Here we describe the development of a plasmid expression system to synthesize recombinant Hbs in Escherichia coli, and we describe...

  11. Prevalence and antibiogram of Escherichia coli O157 isolated from ...

    African Journals Online (AJOL)

    Safty and immunogenic- ity of Escherichia coli O157 O-specific polysacaride conjugate. Christopher, A., Mshana, S. E, Kidenya, B. R, Hokororo, A. and Morona, D. 2013. Bac- teremia and resistant gram-negative pathogens among under-fives in Tanzania. Ital. J. Pediatr., 39, 27-34. Carney, E., O'Brien, S. B., Sheridan, J. J., ...

  12. Stabilization of Escherichia coli uridine phosphorylase by evolution and immobilization

    CSIR Research Space (South Africa)

    Visser, Daniel F

    2010-08-01

    Full Text Available Uridine phosphorylase from Escherichia coli was evolved by iterative saturation mutagenesis. The best mutant showed a temperature optimum of 60C and a half-life of 17.3 h at 60C. The mutant enzyme, as well as a purine nucleoside phosphorylase from...

  13. Fragility of the permeability barrier of Escherichia coli

    NARCIS (Netherlands)

    Haest, C.W.M.; Gier, J. de; Es, G.A. van; Verkleij, A.J.; Deenen, L.L.M. van

    1972-01-01

    An unsaturated fatty acid requiring auxotroph of Escherichia coli was grown with addition of various unsaturated fatty acids. The permeability of the cells for erythritol appeared to be strongly dependent on the fatty acid incorporated in the membrane lipid. Below certain temperatures, depending on

  14. 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 ...

  15. Antibiotic resistance profile of Escherichia coli isolated from five ...

    African Journals Online (AJOL)

    Information on the resistance profiles of clinical and non clinical human bacteria isolates in the developing countries can serve as important means of understanding the human pathogens drug resistance interactions in the zone. Escherichia coli isolated from five geopolitical zones of Nigeria were screened for anti-microbial ...

  16. Search for Enterohaemorrhagic Escherichia coli O157:H7 and ...

    African Journals Online (AJOL)

    Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 and Salmonella enterica are important zoonotic bacteria responsible for enteric infections in humans. The present study investigated the possible role of kittens in the zoonotic transmission of antimicrobial resistant EHEC O157 and Salmonella enterica to human using ...

  17. Antibiotic Resistance in Salmonella sp and Escherichia coli Isolated ...

    African Journals Online (AJOL)

    From the lactose and non lactose fermenters isolated, 16 Salmonella sp and 45 Escherichia coli isolates were identified by colonial morphology on agars, Gram staining, and biochemical tests. The highest mean total aerobic counts of the organism population isolated were obtained from farms C (6.52±0.17logcfu/ml) and D ...

  18. Antibiotic Resistant Salmonella And Escherichia Coli Isolated From ...

    African Journals Online (AJOL)

    Our investigation revealed that Escherichia coli and Salmonella organisms were isolated in the outbreaks. A pattern of antibiotic resistance that seems to be increasing was also found. Considering the role of chickens and its products in the human food chain in Nigeria; and the close interaction between poultry and man, ...

  19. Mutators and hypermutability in bacteria: the Escherichia coli ...

    Indian Academy of Sciences (India)

    Being a mutator is advantageous to the organism when adapting to environmental changes or stressful situations, such as moving from one habitat to another, ... mismatch repair, oxidative DNA damage, mistranslation etc., as well as phenomena associated with these processes, using Escherichia coli as a paradigmatic ...

  20. Escherichia coli bacteraemia in patients with and without haematological malignancies

    DEFF Research Database (Denmark)

    Olesen, B; Kolmos, H J; Orskov, F

    1998-01-01

    We compared serotypes, virulence factors and susceptibility to antibiotics of Escherichia coli strains isolated from 282 patients with bacteraemia. Thirty-five of these were neutropenic patients with haematological malignancy and 247 were patients with a normal or raised total white blood cell co...

  1. Prevalence of Escherichia coli virulence genes in patients with ...

    African Journals Online (AJOL)

    In this study, we investigated the prevalence of the virulence genes specific for five major pathogroups of diarrheagenic Escherichia coli (DEC) in primary cultures from diarrhoeagenic patients in Burkina Faso. Methodology: From September 2016 to Mars 2017, a total of 211 faecal samples from diarrhoeagenic patients from ...

  2. Immunologic Control of Diarrheal Disease Due to Enterotoxigenic Escherichia coli

    Science.gov (United States)

    1984-01-01

    Classical Enteropathogenic (Serotyped) Escherichia coli Strains of Proven Pathogenicity. Infect. Immun. 38:798-801, 1982. 8. Levine, M.M. Vacunas Contra...Microbiol., 18:808-815, 1983. 8 15. Levine, M.M., Lanata, C. Progresos en Vacunas Contra Diarrea Bacteriana. Adelantos Microbiol. Enferm. Inf., 2:67-117

  3. 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...

  4. A scoping study on the prevalence of Escherichia coli and ...

    African Journals Online (AJOL)

    2015-07-04

    Jul 4, 2015 ... ... quality of roof-harvested rainwater was assessed by monitoring the concentrations of Escherichia coli, enterococci, Clostridium perfringens, and Bacteroides spp. in rainwater obtained from tanks in Southeast Queensland,. Australia. Samples were also tested using real-time PCR (with. SYBR Green I dye.

  5. 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...

  6. prevalence and antibiotic resistance patterns of escherichia coli

    African Journals Online (AJOL)

    2014-06-01

    Jun 1, 2014 ... 91 No. 6 June 2014. PREVALENCE AND ANTIBIOTIC RESISTANCE PATTERNS OF ESCHERICHIA COLI AMONG HOSPITALISED ... inpatients at Thika District Hospital (TDH) and to determine antimicrobial resistance patterns to β-lactams .... The World Health Organization (WHO) guidelines recommend ...

  7. Antibacterial effects of zinc oxide nanoparticles on Escherichia coli ...

    African Journals Online (AJOL)

    This study was conducted to evaluate the antibacterial effects of zinc oxide nanoparticles in vitro. Escherichia coli K88 was chosen as an indicator of pathogenic bacteria, because it could cause diarrhea in both children and in early-weaned piglets. In this study, the characterization of the nanoparticles was examined.

  8. Inhibition of respiration of Escherichia coli by thioglycerol.

    OpenAIRE

    Javor, G T

    1983-01-01

    Anaerobic growth on glucose significantly protected Escherichia coli from growth inhibition by thioglycerol. Methionine and anaerobiosis completely overcame growth inhibition by 2 to 90 mM thioglycerol. The respiration of aerobically growing cells was partially inhibited by 20 to 90 mM thioglycerol.

  9. Antibiotic Sensitivity Profile of Escherichia coli Isolated from Poultry ...

    African Journals Online (AJOL)

    A cross sectional study involving 300 cloaca swabs from apparently healthy birds from 8 small-medium scale poultry farms in Ibadan Oyo State was carried out. A total of 201 (67%) Escherichia coli isolates were recovered from the birds and they were subjected to in-vitro antibiotic sensitivity test by agar gel diffusion method.

  10. Modelling nitrogen assimilation of Escherichia coli at low ammonium concentration.

    NARCIS (Netherlands)

    Ma, H.; Boogerd, F.C.; Goryanin, I.

    2009-01-01

    Modelling is an important methodology in systems biology research. In this paper, we presented a kinetic model for the complex ammonium assimilation regulation system of Escherichia coli. Based on a previously published model, the new model included AmtB mediated ammonium transport and AmtB

  11. Effect of visible range electromagnetic radiations on Escherichia coli ...

    African Journals Online (AJOL)

    Background: Escherichia coli is the agent responsible for a range of clinical diseases. With emerging antimicrobial resistance, other treatment options including solar/photo-therapy are becoming increasingly common. Visible Range Radiation Therapy/Colour Therapy is an emerging technique in the field of ...

  12. 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...

  13. Multiple-Resistant Commensal Escherichia Coli from Nigerian ...

    African Journals Online (AJOL)

    Purpose: The antimicrobial susceptibility and virulence traits of 150 strains of Escherichia coli characterized as commensals recovered from faecal samples from pre-school age children in Ile-Ife, Nigeria were evaluated in order to determine their potentials for pathogenicity and their contribution to antibiotic resistance in the ...

  14. Enterohaemorrhagic Escherichia coli O157: a current threat ...

    African Journals Online (AJOL)

    Enterohaemorrhagic. Escherichia coli O157: a survey of dairy cattle in. Tripoli, Libya' (1). The Libyan data presented by Ghen- ghesh et al. in the 1990s were based on the analysis of stool specimens from pediatric patients aged between only a ...

  15. [Mycotic coronary aneurysm with Escherichia coli sepsis: a case report].

    Science.gov (United States)

    Lemoine, J; Popovic, B; Amrein, D; Lemoine, S; Angioi, M; Moulin, F; Ethevenot, G; Aliot, E; Brembilla Perrot, B

    2007-06-01

    We report the case of a patient who was admitted for acute coronary syndrom associated with fever originating from urinary tract. Coronary arteriography revealed a huge coronary aneurysm which ruptured a short time after diagnosis. After surgery, it was proven to be mycotic aneurysm related to Escherichia Coli sepsis.

  16. Gene encoding virulence markers among Escherichia coli isolates ...

    African Journals Online (AJOL)

    driniev

    diarrhoeic stool samples was included. Escherichia coli was isolated and identified by standard cultural and biochemical methods. ... Apart from protozoans such as Giardia lamblia, Enta- moeba histolytica, Cryptosporidium .... Briefly, an overnight bacterial culture was suspended in sterile distilled water and heated at 94°C ...

  17. Glucose transport in Salmonella typhimurium and Escherichia coli

    NARCIS (Netherlands)

    Postma, P. W.; Neyssel, O. M.; van Ree, R.

    1982-01-01

    We have investigated the claim by Schweiger and coworkers [Eur. J. Biochem. 102(1979)231-236] that glucose transport in Escherichia coli is catalyzed mainly by an ATP-dependent transport system instead of the phosphoenolpyruvate:sugar phosphotransferase system. A major argument was the differential

  18. 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 viru...

  19. armA and aminoglycoside resistance in Escherichia coli.

    Science.gov (United States)

    González-Zorn, Bruno; Teshager, Tirushet; Casas, María; Porrero, María C; Moreno, Miguel A; Courvalin, Patrice; Domínguez, Lucas

    2005-06-01

    We report armA in an Escherichia coli pig isolate from Spain. The resistance gene was borne by self-transferable IncN plasmid pMUR050. Molecular analysis of the plasmid and of the armA locus confirmed the spread of this resistance determinant.

  20. Escherichia coli mutants with a temperature-sensitive alcohol dehydrogenase.

    OpenAIRE

    Lorowitz, W; CLARK, D.

    1982-01-01

    Mutants of Escherichia coli resistant to allyl alcohol were selected. Such mutants were found to lack alcohol dehydrogenase. In addition, mutants with temperature-sensitive alcohol dehydrogenase activity were obtained. These mutations, designated adhE, are all located at the previously described adh regulatory locus. Most adhE mutants were also defective in acetaldehyde dehydrogenase activity.

  1. Inactivation of Escherichia coli by titanium dioxide photocatalytic oxidation.

    Science.gov (United States)

    Titanium dioxide in the anatase crystalline form was used as a photocatalyst to generate hydroxyl radicals in a flowthrough water reactor. Experiments were performed on pure cultures of Escherichia coli in dechlorinated tap water and a surface water sample to evaluate the disinfe...

  2. Effect of phytoplankton on Escherichia coli survival in laboratory microcosms

    Science.gov (United States)

    Fecal contamination of water sources is an important water quality issue for agricultural irrigation ponds. Escherichia coli is a common microbial indicator used to evaluate recreational and irrigation water quality. Nuisance algae commonly grow in low- or no-flow irrigation water source The objecti...

  3. Sequencing of Escherichia coli that cause persistent and transient Mastitis

    Science.gov (United States)

    The genomes of two strains of Escherichia coli that cause bovine mastitis were sequenced. These strains are known to be associated with persistent and transient mastitis: strain ECA-B causes a transient infection, and ECC-M leads to a persistent infection....

  4. Characterization of Escherichia coli nucleoids released by osmotic shock

    NARCIS (Netherlands)

    Wegner, S.; Alexeeva, S.V.; Odijk, T.; Woldringh, C.L.

    2012-01-01

    Nucleoids were isolated by osmotic shock from Escherichia coli spheroplasts at relatively low salt concentrations and in the absence of detergents. Sucrose-protected cells, made osmotically sensitive by growth in the presence of ampicillin or by digestion with low lysozyme concentrations (50–5

  5. Antibiotic Resistance of Escherichia coli Isolated from Healthy Food ...

    African Journals Online (AJOL)

    The antimicrobial resistance profile of 204 Escherichia coli isolates of bovine, swine and poultry origin to eight (8) antimicrobial agents was studied. Antimicrobial susceptibility tests were determined using the disk diffusion technique. Full sensitivity to all the eight antimicrobial agents in the test panel was observed in 46 % of ...

  6. 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...

  7. Suppressors of DnaAATP imposed overinitiation in Escherichia coli

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Riber, Leise; Cohen, Malene

    2011-01-01

    Chromosome replication in Escherichia coli is limited by the supply of DnaA associated with ATP. Cells deficient in RIDA (Regulatory Inactivation of DnaA) due to a deletion of the hda gene accumulate suppressor mutations (hsm) to counteract the overinitiation caused by an elevated DnaAATP level...

  8. Occurrence of Escherichia coli in Brassica rapa L. chinensis ...

    African Journals Online (AJOL)

    Low quality water has become valuable resource with restricted or unrestricted use in food production depending on its quality. This study has quantified the occurrence of Escherichia coli in Brassica rapa L. chinensis (Chinese cabbage) vegetables and low quality irrigation water. A total of 106 samples including Chinese ...

  9. Multiple-Resistant Commensal Escherichia Coli from Nigerian ...

    African Journals Online (AJOL)

    Purpose: The antimicrobial susceptibility and virulence traits of 150 strains of Escherichia coli characterized as commensals recovered from faecal samples from pre-school age children in Ile-Ife,. Nigeria were evaluated in order to determine their potentials for pathogenicity and their contribution to antibiotic resistance in the ...

  10. 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...

  11. Antibiotic resistance status of Escherichia coli isolated from healthy ...

    African Journals Online (AJOL)

    Antibiotic resistance status of Escherichia coli isolated from healthy pigs from some piggery farms in Ibadan, Nigeria. ... tetracycline, ampicillin, kanamycin, streptomycin and nalidixic acid (all obtained from SIGMA-ALDRICH, USA) according to standard methods specified by Clinical Laboratory Standards Institute.

  12. Enterohaemorrhagic Escherichia coli O157: a survey of dairy cattle ...

    African Journals Online (AJOL)

    The zoonotic potential of enterohaemorrhagic. Escherichia coli (EHEC) subtype O157 represents a serious food-borne threat to human health. (1Б3). A common animal vector of this pathogen is cattle, and human cases of infection are frequently caused by ingesting food products contaminated with bacteria shed in the ...

  13. Role of wild birds as carriers of multi-drug resistant Escherichia coli and Escherichia vulneris.

    Science.gov (United States)

    Shobrak, Mohammed Y; Abo-Amer, Aly E

    2014-01-01

    Emergence and distribution of multi-drug resistant (MDR) bacteria in environments pose a risk to human and animal health. A total of 82 isolates of Escherichia spp. were recovered from cloacal swabs of migrating and non-migrating wild birds. All bacterial isolates were identified and characterized morphologically and biochemically. 72% and 50% of isolates recovered from non-migrating and migrating birds, respectively, showed positive congo red dye binding (a virulence factor). Also, hemolysin production (a virulence factor) was showed in 8% of isolates recovered from non-migrating birds and 75% of isolates recovered from migrating birds. All isolates recovered from non-migrating birds were found resistant to Oxacillin while all isolates recovered from migrating birds demonstrated resistance to Oxacillin, Chloramphenicol, Oxytetracycline and Lincomycin. Some bacterial isolates recovered from non-migrating birds and migrating birds exhibited MDR phenotype. The MDR isolates were further characterized by API 20E and 16S rRNA as E. coli and E. vulneris. MDR Escherichia isolates contain ~1-5 plasmids of high-molecular weights. Accordingly, wild birds could create a potential threat to human and animal health by transmitting MDR bacteria to water streams and other environmental sources through their faecal residues, and to remote regions by migration.

  14. Escherichia Coli Removal from Water Using Electrophotocatalytic ...

    African Journals Online (AJOL)

    Michael Horsfall

    -40). The findings showed the ... nanoparticles stabilized on zinc. As safe drinking water should not contain E. coli, this organism was studied as the model organism and an indicator in this study. ..... performance paint coatings. Asian J. Exp.

  15. Heterologous biosynthesis of triterpenoid ambrein in engineered Escherichia coli.

    Science.gov (United States)

    Ke, Di; Caiyin, Qinggele; Zhao, Fanglong; Liu, Ting; Lu, Wenyu

    2018-02-01

    To genetically engineer Escherichia coli for the heterologous biosynthesis of triterpenoid, ambrein, the main bioactive component of ambergris, by constituting a novel squalene-derived ambrein biosynthetic pathway in E. coli. The ScERG9 gene encoding the squalene synthase (SS) was integrated into the E. coli genome to generate a squalene-producing strain that supplied the central precursor squalene for the formation of cyclic triterpenoids. The mutated squalene-hopene synthase (D377C SHC) and the tetraprenyl-β-curcumene cyclase (BmeTC) were co-expressed with SS to construct a novel ambrein biosynthetic pathway in E. coli. Ambrein was produced at 2.6 mg l -1 . An E. coli chassis for ambrein production was constructed by combining the squalene synthesis module with the downstream cyclization module.

  16. Phenotypic Changes Exhibited by E. coli Cultured in Space

    Directory of Open Access Journals (Sweden)

    Luis Zea

    2017-08-01

    Full Text Available Bacteria will accompany humans in our exploration of space, making it of importance to study their adaptation to the microgravity environment. To investigate potential phenotypic changes for bacteria grown in space, Escherichia coli was cultured onboard the International Space Station with matched controls on Earth. Samples were challenged with different concentrations of gentamicin sulfate to study the role of drug concentration on the dependent variables in the space environment. Analyses included assessments of final cell count, cell size, cell envelope thickness, cell ultrastructure, and culture morphology. A 13-fold increase in final cell count was observed in space with respect to the ground controls and the space flight cells were able to grow in the presence of normally inhibitory levels of gentamicin sulfate. Contrast light microscopy and focused ion beam/scanning electron microscopy showed that, on average, cells in space were 37% of the volume of their matched controls, which may alter the rate of molecule–cell interactions in a diffusion-limited mass transport regime as is expected to occur in microgravity. TEM imagery showed an increase in cell envelope thickness of between 25 and 43% in space with respect to the Earth control group. Outer membrane vesicles were observed on the spaceflight samples, but not on the Earth cultures. While E. coli suspension cultures on Earth were homogenously distributed throughout the liquid medium, in space they tended to form a cluster, leaving the surrounding medium visibly clear of cells. This cell aggregation behavior may be associated with enhanced biofilm formation observed in other spaceflight experiments.

  17. Binding characteristics of S fimbriated Escherichia coli to isolated brain microvascular endothelial cells.

    Science.gov (United States)

    Stins, M. F.; Prasadarao, N. V.; Ibric, L.; Wass, C. A.; Luckett, P.; Kim, K. S.

    1994-01-01

    To assess the role of S fimbriae in the pathogenesis of Escherichia coli meningitis, transformants of E. coli strains with or without S fimbriae plasmid were compared for their binding to microvessel endothelial cells isolated from bovine brain cortices (BMEC). The BMEC's displayed a cobblestone appearance, were positive for factor VIII, carbonic anhydrase IV, took up fluorescent-labeled acetylated low density lipoprotein, and exhibited gamma glutamyl transpeptidase activity. Binding of S fimbriated E. coli to BMEC was approximately threefold greater than nonfimbriated E. coli Similarly S fimbriated E. coli bound to human brain endothelial cells approximately threefold greater than nonfimbriated E. coli. Binding was reduced approximately 60% by isolated S fimbriae and about 80% by anti-S adhesin antibody. Mutating the S adhesin gene resulted in a complete loss of the binding, whereas mutagenesis of the major S fimbriae subunit gene sfaA did not significantly affect binding. Pretreatment of BMEC with neuraminidase or prior incubation of S fimbriated E. coli with NeuAc alpha 2,3-sialyl lactose completely abolished binding. These findings indicate that S fimbriated E. coli bind to NeuAc alpha 2,3-galactose containing glycoproteins on brain endothelial cells via a lectin-like activity of SfaS adhesin. This might be an important early step in the penetration of bacteria across the blood-brain barrier in the development of E. coli meningitis. Images Figure 6 PMID:7977653

  18. Escherichia coli-mediated impairment of ureteric contractility is uropathogenic E. coli specific.

    Science.gov (United States)

    Floyd, Rachel V; Upton, Mathew; Hultgren, Scott J; Wray, Susan; Burdyga, Theodor V; Winstanley, Craig

    2012-11-15

    Ureters are fundamental for keeping kidneys free from uropathogenic Escherichia coli (UPEC), but we have shown that 2 strains (J96 and 536) can subvert this role and reduce ureteric contractility. To determine whether this is (1) a widespread feature of UPEC, (2) exhibited only by UPEC, and (3) dependent upon type 1 fimbriae, we analyzed strains representing epidemiologically important multilocus sequence types ST131, ST73, and ST95 and non-UPEC E. coli. Contractility and calcium transients in intact rat ureters were compared between strains. Mannose and fim mutants were used to investigate the role of type 1 fimbriae. Non-UPEC had no significant effect on contractility, with a mean decrease after 8 hours of 8.8%, compared with 8.8% in controls. UPEC effects on contractility were strain specific, with decreases from 9.47% to 96.7%. Mannose inhibited the effects of the most potent strains (CFT073 and UTI89) but had variable effects among other UPEC strains. Mutation and complementation studies showed that the effects of the UTI89 cystitis isolate were fimH dependent. We find that (1) non-UPEC do not affect ureteric contractility, (2) impairment of contractility is a common feature of UPEC, and (3) the mechanism varies between strains, but for the most potent UPEC type 1 fimbriae are involved.

  19. Photoreactivation of Escherichia coli is impaired at high growth temperatures.

    Science.gov (United States)

    Xu, Lei; Tian, Changqing; Lu, Xiaohua; Ling, Liefeng; Lv, Jun; Wu, Mingcai; Zhu, Guoping

    2015-06-01

    Photolyase repairs UV-induced lesions in DNA using light energy, which is the principle of photoreactivation. Active photolyase contains the two-electron-reduced flavin cofactor. We observed that photoreactivation of Escherichia coli was impaired at growth temperatures ⩾37°C, and growth in this temperature range also resulted in decreased photolyase protein levels in the cells. However, the levels of phr transcripts (encoding photolyase) were almost unchanged at the various growth temperatures. A lacZ-reporter under transcriptional control of the phr promoter showed no temperature-dependent expression. However, a translational reporter consisting of the photolyase N-terminal α/β domain-LacZ fusion protein exhibited lower β-galactosidase activity at high growth temperatures (37-42°C). These results indicated that the change in photolyase levels at different growth temperatures is post-transcriptional in nature. Limited proteolysis identified several susceptible cleavage sites in E. coli photolyase. In vitro differential scanning calorimetry and activity assays revealed that denaturation of active photolyase occurs at temperatures ⩾37°C, while apo-photolyase unfolds at temperatures ⩾25°C. Evidence from temperature-shift experiments also implies that active photolyase is protected from thermal unfolding and proteolysis in vivo, even at 42°C. These results suggest that thermal unfolding and proteolysis of newly synthesized apo-photolyase, but not active photolyase, is responsible for the impaired photoreactivation at high growth temperatures (37-42°C). Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Adhesive threads of extraintestinal pathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Antão Esther-Maria

    2009-12-01

    Full Text Available Abstract The ability to adhere to host surfaces is by far the most vital step in the successful colonization by microbial pathogens. Colonization begins with the attachment of the bacterium to receptors expressed by cells forming the lining of the mucosa. Long hair like extracellular appendages called fimbriae, produced by most Gram-negative pathogens, mediate specific attachment to the epithelial cell surface. Associated with the fimbriae is a protein called an adhesin, which directs high-affinity binding to specific cell surface components. In the last couple of years, an enormous amount of research has been undertaken that deals with understanding how bacterial pathogens adhere to host cells. E. coli in all probability is one of the best studied free-living organisms. A group of E. coli called Extraintestinal pathogenic E. coli (ExPEC including both human and animal pathogens like Uropathogenic E. coli (UPEC, Newborn meningitic E. coli (NMEC and Avian pathogenic E. coli (APEC, have been found to harbour many fimbriae including Type 1 fimbriae, P fimbriae, curli fibres, S fimbriae, F1C fimbriae, Dr fimbriae, afimbrial adhesins, temperature-sensitive haemagglutinin and many novel adhesin gene clusters that have not yet been characterized. Each of these adhesins is unique due to the recognition of an adhesin-specific receptor, though as a group these adhesins share common genomic organization. A newly identified putative adhesin temporarily termed ExPEC Adhesin I, encoded by gene yqi, has been recently found to play a significant role in the pathogenesis of APEC infection, thus making it an interesting candidate for future research. The aim of this review is to describe the role of ExPEC adhesins during extraintestinal infections known till date, and to suggest the idea of investigating their potential role in the colonization of the host gut which is said to be a reservoir for ExPEC.

  1. Recombinant expression, refolding, purification and characterization of Pseudomonas aeruginosa protease IV in Escherichia coli.

    Science.gov (United States)

    Zhao, Mingzhi; Cai, Man; Wu, Feilin; Zhang, Yao; Xiong, Zhi; Xu, Ping

    2016-10-01

    Several protease IV enzymes are widely used in proteomic research. Specifically, protease IV from Pseudomonas aeruginosa has lysyl endopeptidase activity. Here, we report the recombinant expression, refolding, activation, and purification of this protease in Escherichia coli. Proteolytic instability of the activated intermediate, a major obstacle for efficient production, is controlled through ammonium sulfate precipitation. The purified protease IV exhibits superior lysyl endopeptidase activity compared to a commercial product. Copyright © 2016. Published by Elsevier Inc.

  2. Characterization of avian pathogenic Escherichia coli isolated in eastern China.

    Science.gov (United States)

    Dou, Xinhong; Gong, Jiansen; Han, Xiangan; Xu, Ming; Shen, Haiyu; Zhang, Di; Zhuang, Linlin; Liu, Jiasheng; Zou, Jianmin

    2016-01-15

    In order to investigate the biological characteristics of avian pathogenic Escherichia coli (APEC) isolated in eastern China, a total of 243 isolates were isolated from diseased poultry on different farms during the period from 2007 to 2014. These isolates were characterized for serogroups (polymerase chain reaction and agglutination), the presence of virulence-associated genes (fimC, iss, ompA, fyuA, stx2f, iroC, iucD, hlyE, tsh, cvaC, irp2, and papC) and class I integrons (polymerase chain reaction), drug susceptibilities (disk diffusion method) and the biofilm-forming abilities (semi-quantitative method). The results showed that the most predominant serogroups were O78 (87 isolates, 35.8%) and O2 (35 isolates, 14.4%). Gene profiling found that fimC and ompA were frequently distributed among the isolates and that 77.4% of the isolates were positive for class 1 integrons. Overall, isolates displayed resistance to tetracycline (97.5%), nalidixic acid (82.3%), ampicillin (81.1%), sulphafurazole (80.7%), streptomycin (79.0%), trimethoprim (78.2%) and cotrimoxazole (78.2%). Multiple-drug resistance was exhibited in 80.3% of the isolates, and the presence of class 1 integrons is associated with multidrug resistance. Finally, 151 isolates had the ability to form biofilms in vitro, and drug resistance seemed relative to biofilm-forming abilities. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Production of salidroside in metabolically engineered Escherichia coli

    Science.gov (United States)

    Bai, Yanfen; Bi, Huiping; Zhuang, Yibin; Liu, Chang; Cai, Tao; Liu, Xiaonan; Zhang, Xueli; Liu, Tao; Ma, Yanhe

    2014-01-01

    Salidroside (1) is the most important bioactive component of Rhodiola (also called as “Tibetan Ginseng”), which is a valuable medicinal herb exhibiting several adaptogenic properties. Due to the inefficiency of plant extraction and chemical synthesis, the supply of salidroside (1) is currently limited. Herein, we achieved unprecedented biosynthesis of salidroside (1) from glucose in a microorganism. First, the pyruvate decarboxylase ARO10 and endogenous alcohol dehydrogenases were recruited to convert 4-hydroxyphenylpyruvate (2), an intermediate of L-tyrosine pathway, to tyrosol (3) in Escherichia coli. Subsequently, tyrosol production was improved by overexpressing the pathway genes, and by eliminating competing pathways and feedback inhibition. Finally, by introducing Rhodiola-derived glycosyltransferase UGT73B6 into the above-mentioned recombinant strain, salidroside (1) was produced with a titer of 56.9 mg/L. Interestingly, the Rhodiola-derived glycosyltransferase, UGT73B6, also catalyzed the attachment of glucose to the phenol position of tyrosol (3) to form icariside D2 (4), which was not reported in any previous literatures. PMID:25323006

  4. 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...

  5. Enterohemorrhagic Escherichia coli O157 in Libya

    African Journals Online (AJOL)

    zation of diarrheagenic E. coli from diarrheic Libyan children, clearly stated that EHEC was not detected in the stool specimens examined. However, a study from Tunisia examined 212 stool samples from diarrheic and non-diarrheic children and adults for EHEC using PCR-based techniques (2). They observed 11 isolates ...

  6. Genetic characterization of commensal Escherichia coli isolated from laboratory rodents.

    Science.gov (United States)

    Loong, Shih Keng; Mahfodz, Nur Hidayana; Che Mat Seri, Nurul Asma Anati; Mohamad Wali, Haryanti Azura; Abd Gani, Syahar Amir; Wong, Pooi-Fong; AbuBakar, Sazaly

    2016-01-01

    Escherichia coli, a commensal in the intestines of vertebrates, is capable of colonizing many different hosts and the environment. Commensal E. coli strains are believed to be the precursor of pathogenic strains by means of acquisition of antimicrobial resistant and virulence genes. Laboratory rodents are inherently susceptible to numerous known infectious agents, which could transfer virulence determinants to commensal E. coli. Hence, in this study, the genetic structure of commensal E. coli found in laboratory rodents and their antimicrobial resistance profiles were investigated. E. coli strains belonging to phylogroup A were the predominant strain obtained from the animals used in the study. Four novel sequence types (ST746, ST747, ST748 and ST749) were discovered using the multi locus sequence typing, together with one common ST357 in the gastrointestinal tract, liver and, the trachea and lung. Serotyping demonstrated that these commensal E. coli strains were non-Shiga toxin-producers. Phenotypic and genotypic analyses of extended spectrum beta lactamases were also negative. These findings implied that the E. coli strains recovered from the laboratory rodents were truly commensal in nature. Further study is required to investigate the possible influence of gender on the susceptibility of hosts to E. coli colonization in laboratory rodents.

  7. Incidence of Escherichia coli  - Glucuronidase Positive on Goat Milk

    Directory of Open Access Journals (Sweden)

    Zorica Voşgan

    2016-11-01

    Full Text Available Papers on beta- glucuronidase sensitivity and specificity for identifying Escherichia coli in sources of environment, food, water, etc. have been published since 1976. In this study we conducted a review of the incidence of E. coli β- glucuronidase -positive in goat milk, obtained by hand milking throughout the lactation: spring, summer, autumn. The presence of E. coli in milk is considered both as a health indicator and a pathogenic factor capable of causing food poisoning. The determination of the E. coli β-glucuronidase-positive was carried using TBX medium by cultivating colonies typical blue at 440C. The absence of E. coli in milk yielded during the spring, when the animal milking is done three times a day, was found in the performed analyses; the same was observed during fall, when the milk production is lower and the milking is done once a day. The load of E. coli β-glucuronidase-positive was averaging 66.67 CFU/ml of goat milk, during the middle lactation period (July-August, in conditions of higher temperature. During this period, milking is done in the mountain zone, where the transhumance of animals takes place in summer. The presence of the species E. coli was also confirmed by microscopic examination. Attention should be paid to hygiene and milk should be immediately cooled, during hot weather, as E. coli can be a source of food poisoning.

  8. Genomic Comparative Study of Bovine Mastitis Escherichia coli

    Science.gov (United States)

    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 is a bias in the distribution of mastitis isolates in the different phylogenetic groups of the E. coli species, with the majority of strains belonging to phylogenetic groups A and B1. An interesting feature is that clustering of strains based on their accessory genome is very similar to that obtained using the core genome. This finding illustrates the fact that phenotypic properties of strains from different phylogroups are likely to be different. As a consequence, it is possible that different strategies could be used by mastitis isolates of different phylogroups to trigger mastitis. Our results indicate that mastitis E. coli isolates analyzed in this study carry very few of the virulence genes described in other pathogenic E. coli strains. A more detailed analysis of the presence/absence of genes involved in LPS synthesis, iron acquisition and type 6 secretion systems did not uncover specific properties of mastitis isolates. Altogether, these results indicate that mastitis E. coli isolates are rather characterized by a lack of bona fide currently described virulence genes. PMID:26809117

  9. Chromosomal features of Escherichia coli serotype O2:K2, an avian pathogenic E. coli.

    Science.gov (United States)

    Jørgensen, Steffen L; Kudirkiene, Egle; Li, Lili; Christensen, Jens P; Olsen, John E; Nolan, Lisa; Olsen, Rikke H

    2017-01-01

    Escherichia coli causing infection outside the gastrointestinal system are referred to as extra-intestinal pathogenic E. coli. Avian pathogenic E. coli is a subgroup of extra-intestinal pathogenic E. coli and infections due to avian pathogenic E. coli have major impact on poultry production economy and welfare worldwide. An almost defining characteristic of avian pathogenic E. coli is the carriage of plasmids, which may encode virulence factors and antibiotic resistance determinates. For the same reason, plasmids of avian pathogenic E. coli have been intensively studied. However, genes encoded by the chromosome may also be important for disease manifestation and antimicrobial resistance. For the E. coli strain APEC_O2 the plasmids have been sequenced and analyzed in several studies, and E. coli APEC_O2 may therefore serve as a reference strain in future studies. Here we describe the chromosomal features of E. coli APEC_O2. E. coli APEC_O2 is a sequence type ST135, has a chromosome of 4,908,820 bp (plasmid removed), comprising 4672 protein-coding genes, 110 RNA genes, and 156 pseudogenes, with an average G + C content of 50.69%. We identified 82 insertion sequences as well as 4672 protein coding sequences, 12 predicated genomic islands, three prophage-related sequences, and two clustered regularly interspaced short palindromic repeats regions on the chromosome, suggesting the possible occurrence of horizontal gene transfer in this strain. The wildtype strain of E. coli APEC_O2 is resistant towards multiple antimicrobials, however, no (complete) antibiotic resistance genes were present on the chromosome, but a number of genes associated with extra-intestinal disease were identified. Together, the information provided here on E. coli APEC_O2 will assist in future studies of avian pathogenic E. coli strains, in particular regarding strain of E. coli APEC_O2, and aid in the general understanding of the pathogenesis of avian pathogenic E. coli.

  10. EcoCyc: Enyclopedia of Escherichia coli Genes and Metabolism.

    Science.gov (United States)

    Karp, P D; Riley, M; Paley, S M; Pellegrini-Toole, A; Krummenacker, M

    1997-01-01

    The Encyclopedia of Genes and Metabolism (EcoCyc) is a database that combines information about the genome and the intermediary metabolism of Escherichia coli. It describes 2970 genes of E.coli, 547 enzymes encoded by these genes, 702 metabolic reactions that occur in E.coli and the organization of these reactions into 107 metabolic pathways. The EcoCyc graphical user interface allows scientists to query and explore the EcoCyc database using visualization tools such as genomic-map browsers and automatic layouts of metabolic pathways. EcoCyc spans the space from sequence to function to allow scientists to investigate an unusually broad range of questions. EcoCyc can be thought of as both an electronic review article because of its copious references to the primary literature, and as an in silicio model of E.coli metabolism that can be probed and analyzed through computational means.

  11. 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.

  12. Biosynthetic pathway for poly(3-hydroxypropionate) in recombinant Escherichia coli.

    Science.gov (United States)

    Wang, Qi; Liu, Changshui; Xian, Mo; Zhang, Yongguang; Zhao, Guang

    2012-08-01

    Poly(3-hydroxypropionate) (P3HP) is a biodegradable and biocompatible thermoplastic. In this study, we engineered a P3HP biosynthetic pathway in recombinant Escherichia coli. The genes for malonyl-CoA reductase (mcr, from Chloroflexus aurantiacus), propionyl-CoA synthetase (prpE, from E. coli), and polyhydroxyalkanoate synthase (phaC1, from Ralstonia eutropha) were cloned and expressed in E. coli. The E. coli genes accABCD encoding acetyl-CoA carboxylase were used to channel the carbon into the P3HP pathway. Using glucose as a sole carbon source, the cell yield and P3HP content were 1.32 g/L and 0.98% (wt/wt [cell dry weight]), respectively. Although the yield is relatively low, our study shows the feasibility of engineering a P3HP biosynthetic pathway using a structurally unrelated carbon source in bacteria.

  13. 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 uptake...

  14. Characterization of Escherichia coli populations from gulls, landfill trash, and wastewater using ribotyping.

    Science.gov (United States)

    Nelson, M; Jones, S H; Edwards, C; Ellis, J C

    2008-08-19

    Due to their opportunistic and gregarious nature, gulls may be important reservoirs and vectors for anthropogenically derived fecal pathogens in coastal areas. We used ribotyping, a genotypic bacterial source tracking method, to compare populations of Escherichia coli among herring gulls Larus argentatus, great black-backed gulls L. marinus, wastewater, and landfill trash in New Hampshire and Maine, USA. Concentrations of E. coli in gull feces varied widely among individuals, but were generally high (6.0 x 10(1) to 2.5 x 10(9) g(-1) wet weight). Of 39 E. coli isolates from L. argentatus, 67% had banding patterns that were > or = 90% similar to those from wastewater and trash, whereas only 39% of 36 L. marinus isolates exhibited > or = 90% similarity to these sources. Strains of E. coli from gulls matched (> or = 90% similarity) more strains from wastewater (39% matching) than from trash (15% matching). E. coli isolates from L. marinus feces exhibited a greater diversity of banding patterns than did isolates from L. argentatus. There were more unique E. coli banding patterns in trash samples than in wastewater, and higher diversity indices in the former compared to the latter. These findings suggest that both species of gulls, especially L. argentatus, obtain fecal bacteria from wastewater and landfill trash, which they may transport to recreational beaches and waters. Our results also indicate that E. coli populations may vary widely between gull species, and between the anthropogenic habitats that they frequent, i.e. landfills and wastewater treatment facilities.

  15. The capsule plays an important role in Escherichia coli K1 interactions with Acanthamoeba.

    Science.gov (United States)

    Jung, Suk-Yul; Matin, Abdul; Kim, Kwang Sik; Khan, Naveed Ahmed

    2007-03-01

    Escherichia coli K1 is shown to bind to, associate with, invade and survive inside Acanthamoeba, but the precise mechanisms associated with these events are unclear. We have previously shown that outer membrane protein A and lipopolysaccharide are critical bacterial determinants involved in E. coli K1 interactions with Acanthamoeba. Using an isogenic K1 capsule-deletion mutant (lacking the neuDB genes cluster that is necessary for the production of cytoplasmic precursors to the exopolysaccharide capsule), we observed that the capsule modulates and enhances E. coli K1 association and survival inside Acanthamoeba. The capsule-deletion mutant exhibited significantly reduced association compared with the wild type strain, E44. Similarly, the K1 capsule-deletion mutant exhibited limited ability for invasion/uptake by and survival inside Acanthamoeba. Next, we determined whether E. coli K1 survive inside Acanthamoeba during the encystment process and that viable bacteria can be isolated from the mature cysts. Using encystment assays, our findings revealed that E. coli K1, but not its capsule-deletion mutant, exhibit survival inside Acanthamoeba cysts. We believe this is the first demonstration that the K1 capsule plays an important role in E. coli K1 interactions with Acanthamoeba.

  16. Resistance and virulence factors of Escherichia coli isolated from chicken.

    Science.gov (United States)

    Pavlickova, Silvie; Dolezalova, Magda; Holko, Ivan

    2015-01-01

    Chicken meat has become an important part of the human diet and besides contamination by pathogenic Escherichia coli there is a risk of antibiotic resistance spreading via the food chain. The purpose of this study was to examine the prevalence of resistance against eight antibiotics and the presence of 14 virulence factors among 75 Escherichia coli strains isolated from chicken meat in the Czech Republic after classification into phylogenetic groups by the multiplex PCR method. More than half of strains belonged to A phylogroup, next frequently represented was B1 phylogroup, which suggests the commensal strains. The other strains were classified into phylogroups B2 and D, which had more virulence factors. Almost half of all E. coli strains were resistant to at least one of eight-tested antibiotics. A multidrug resistance was observed in 13% of strains. The most prevalent virulence genes were iucD, iss and tsh. None of genes encoding toxins was detected. Most of E. coli strains isolated from chicken meat can be considered as nonpathogenic on the basis of analysis of virulence factors, antibiotic resistance and phylogroups assignment. It can provide a useful tool for prediction of a potential risk from food contaminated by E. coli.

  17. Temporal variations of Escherichia coli concentrations in a large Midwestern river

    Science.gov (United States)

    Schilling, K.E.; Zhang, Y.-K.; Hill, D.R.; Jones, C.S.; Wolter, C.F.

    2009-01-01

    The Raccoon River used by the Des Moines Water Works to serve more than 400,000 people in central Iowa is threatened by contamination from Escherichia coli bacteria from point and nonpoint sources. The 9389 km2 watershed is highly agricultural, with 73% of the land in row crop production and widespread animal production. Results from 2155 grab samples from 1997 to 2005 for E. coli analysis were examined for temporal variations. E. coli concentrations were found to vary across years, seasons, and flow conditions, with a 9-year mean value of 1156 most probable number (MPN)/100 ml. Monthly concentrations exhibited clear seasonality with highest values in May through July. Although E. coli concentrations were higher during periods of greater discharge, the relation of log E. coli to log discharge was not particularly strong (r2 = 0.35). The variogram of E. coli concentrations showed temporal correlation within a span of 4 days suggesting that concentrations measured on 1 day may be related in time to concentrations measured up to 3 days later and beyond 4 days the concentrations vary randomly. The spectral analysis of the time series of E. coli was also carried out and was fitted well with the spectrum of an exponential covariance function. Deciphering temporal patterns and correlation of E. coli bacteria in streams may be useful for developing future monitoring strategies to track concentration patterns and loads. ?? 2008 Elsevier B.V. All rights reserved.

  18. 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....... 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....

  19. 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...

  20. Gentamicin resistance among Escherichia coli strains isolated in neonatal sepsis.

    Science.gov (United States)

    Hasvold, J; Bradford, L; Nelson, C; Harrison, C; Attar, M; Stillwell, T

    2013-01-01

    Neonatal sepsis is a significant cause of morbidity and mortality among term and preterm infants. Ampicillin and gentamicin are standard empiric therapy for early onset sepsis. Four cases of neonatal sepsis secondary to Escherichia coli (E. coli) found to be gentamicin resistant occurred within a five week period in one neonatal intensive care unit (NICU). To determine whether these cases could be tied to a single vector of transmission, and to more broadly evaluate the incidence of gentamicin resistant strains of E. coli in the neonatal population at our institution compared to other centers, we reviewed the charts of the four neonates (Infants A through D) and their mothers. The E. coli isolates were sent for Pulse Field Gel Electrophoresis (PFGE) to evaluate for genetic similarity between strains. We also reviewed all positive E. coli cultures from one NICU over a two year period. Infants A and B had genetically indistinguishable strains which matched that of urine and placental cultures of Infant B's mother. Infant C had a genetically distinct organism. Infant D, the identical twin of Infant C, did not have typing performed. Review of all cultures positive for E. coli at our institution showed a 12.9 percent incidence of gentamicin-resistance. A review of other studies showed that rates of resistance vary considerably by institution. We conclude that gentamicin-resistant E. coli is a relatively uncommon cause of neonatal sepsis, but should remain a consideration in patients who deteriorate despite initiation of empiric antibiotics.

  1. Surface modification of PLGA nanoparticles to deliver nitric oxide to inhibit Escherichia coli growth

    Energy Technology Data Exchange (ETDEWEB)

    Reger, Nina A. [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); Meng, Wilson S. [Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282 (United States); Gawalt, Ellen S., E-mail: gawalte@duq.edu [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219 (United States)

    2017-04-15

    Highlights: • Thin film functionalized PLGA nanoparticles were modified to release nitric oxide from an s-nitrosothiol donor. • The nitric oxide modified nanoparticles were bacteriostatic against Escherichia coli. • The nitric oxide modified nanoparticles increased the effectiveness of tetracycline against Escherichia coli. • The modified nitric oxide nanoparticles did not exhibit cytotoxic effects against fibroblasts. - Abstract: Polymer nanoparticles consisting of poly (DL-lactic-co-glycolic acid) were surface functionalized to deliver nitric oxide. These biodegradable and biocompatible nanoparticles were modified with an S-nitrosothiol molecule, S-nitrosocysteamine, as the nitric oxide delivery molecule. S-nitrosocysteamine was covalently immobilized on the nanoparticle surface using small organic molecule linkers and carbodiimide coupling. Nanoparticle size, zeta potential, and morphology were determined using dynamic light scattering and scanning electron microscopy, respectively. Subsequent attachment of the S-nitrosothiol resulted in a nitric oxide release of 37.1 ± 1.1 nmol per milligram of nanoparticles under physiological conditions. This low concentration of nitric oxide reduced Escherichia coli culture growth by 31.8%, indicating that the nitric oxide donor was effective at releasing nitric oxide even after attachment to the nanoparticle surface. Combining the nitric oxide modified nanoparticles with tetracycline, a commonly prescribed antibiotic for E. coli infections, increased the effectiveness of the antibiotic by 87.8%, which allows for lower doses of antibiotics to be used in order to achieve the same effect. The functionalized nanoparticles were not cytotoxic to mouse fibroblasts.

  2. TRYPTOPHANASE-TRYPTOPHAN SYNTHETASE SYSTEMS IN ESCHERICHIA COLI III.

    Science.gov (United States)

    Freundlich, Martin; Lichstein, Herman C.

    1962-01-01

    Freundlich, Martin (University of Minnesota, Minneapolis) and Herman C. Lichstein. Tryptophanase-tryptophan synthetase systems in Escherichia coli. III. Requirements for enzyme synthesis. J. Bacteriol. 84:996–1006. 1962.—The requirements for the formation of tryptophanase and tryptophan synthetase in Escherichia coli during repression release were studied. The kinetics of the formation of tryptophan synthetase differed in the two strains examined; this was attributed to differences in the endogenous level of tryptophan in the bacterial cells. The formation of both enzymes was inhibited by chloramphenicol, and by the absence of arginine in an arginine-requiring mutant. These results are indicative of a requirement for protein synthesis for enzyme formation. Requirements for nucleic acid synthesis were examined by use of a uracil- and thymine-requiring mutant, and with purine and pyrimidine analogues. The results obtained suggest that some type of ribonucleic acid synthesis was necessary for the formation of tryptophanase and tryptophan synthetase. PMID:13959620

  3. Tranformasi Fragmen Dna Kromosom Xanthomonas Campestris ke dalam Escherichia Coli

    Directory of Open Access Journals (Sweden)

    Wibowo Mangunwardoyo

    2002-04-01

    Full Text Available Research on DNA transformation of Xanthomonas campestris into Escherichia coli DH5αα using plasmid vector Escherichia coli (pUC19. was carried out. DNA chromosome was isolated using CTAB method, alkali lysis method was used to isolate DNA plasmid. Both of DNA plasmid and chromosome were digested using restriction enzyme EcoRI. Competent cell was prepared with CaCl2 and heat shock method for transformation procedure. The result revealed transformation obtain 5 white colonies, with transformation frequency was 1,22 x 10-8 colony/competent cell. Electrophoresis analysis showed the DNA fragment (insert in range 0.5 – 7,5 kb. Further research should be carried out to prepare the genomic library to obtain better result of transformant.

  4. Studies of the Escherichia coli Rsd-sigma70 complex.

    Science.gov (United States)

    Westblade, Lars F; Ilag, Leopold L; Powell, Andrew K; Kolb, Annie; Robinson, Carol V; Busby, Stephen J W

    2004-01-16

    Escherichia coli Rsd protein was previously identified on the basis of its binding to the RNA polymerase sigma(70) subunit. The Rsd-sigma(70) complex has been studied using different methods. Our data show that Rsd associates with sigma(70) to form a complex with a stoichiometry of 1:1. Alanine scanning and deletion mutagenesis were used to locate regions of sigma(70) that are required for the formation of the Rsd-sigma(70) complex.

  5. Sequence elements in the Escherichia coli araFGH promoter.

    OpenAIRE

    Hendrickson, W; Flaherty, C.; Molz, L

    1992-01-01

    The Escherichia coli araFGH operon codes for proteins involved in the L-arabinose high-affinity transport system. Transcriptional regulation of the operon was studied by creating point mutations and deletions in the control region cloned into a GalK expression vector. The transcription start site was confirmed by RNA sequencing of transcripts. The sequences essential for polymerase function were localized by deletions and point mutations. Surprisingly, only a weak -10 consensus sequence, and ...

  6. (ESBL)-producing Escherichia coli isolated from cl

    African Journals Online (AJOL)

    Ann Lab Med 2014; 34(2): 139-144. 24. Fuentes Arriaga R, Talavera Rojas M, Vázquez. Navarrete J, Soriano Vargas E, Gutiérrez Castillo A. Presencia de integrones clase I en Escherichia coli aislada de productos cárnicos en plantas Tipo. Inspección Federal (TIF) en el Estado de México. Vet. Mexico 2013; 44(1): 23-30.

  7. 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.

  8. Two Tales of Prokaryotic Genomic Diversity: Escherichia coli and Halophiles

    Directory of Open Access Journals (Sweden)

    Lejla Pašić

    2014-01-01

    Full Text Available Prokaryotes are generally characterized by vast genomic diversity that has been shaped by mutations, horizontal gene transfer, bacteriocins and phage predation. Enormous genetic diversity has developed as a result of stresses imposed in harsh environments and the ability of microorganisms to adapt. Two examples of prokaryotic diversity are presented: on intraspecies level, exemplified by Escherichia coli, and the diversity of the hypersaline environment, with the discussion of food-related health issues and biotechnological potential.

  9. Removal of Escherichia coli from biological effluents using natural ...

    African Journals Online (AJOL)

    Ability for disinfecting sterile biological effluents inoculated with Escherichia coli ATCC 25922 at concentrations of 105 CFU/m., using a natural mineral aggregate (NMA) and artificial mineral aggregates (AMAfs) consisting of individual oxides as Fe2O3, Cu2O y Ag2O and combined oxides as Fe2O3-Cu2O, Fe2O3-Ag2O, ...

  10. flu, a metastable gene controlling surface properties of Escherichia coli.

    OpenAIRE

    Diderichsen, B

    1980-01-01

    flu, a gene of Escherichia coli K-12, was discovered and mapped between his and shiA. It is shown that flu is a metastable gene that changes frequently between the flu+ and flu states. flu+ variants give stable homogeneous suspensions, are piliated, and form glossy colonies. flu variants aggregate, fluff and sediment from suspensions, are nonpiliated, and form frizzy colonies. flu+ and flu variants can be isolated from most strains. Implications of these observations are discussed, and it is ...

  11. The effect of spatial structure on adaptation in Escherichia coli

    OpenAIRE

    Perfeito, Lilia; Pereira, M. Inês; Campos, Paulo R. A.; Gordo, Isabel

    2007-01-01

    Populations of organisms are generally organized in a given spatial structure. However, the vast majority of population genetic studies are based on populations in which every individual competes globally. Here we use experimental evolution in Escherichia coli to directly test a recently made prediction that spatial structure slows down adaptation and that this cost increases with the mutation rate. This was studied by comparing populations of different mutation rates adapting to a liquid (un...

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

    DEFF Research Database (Denmark)

    Steiner, Uli

    2014-01-01

    are 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 simple organisms are expected to show senescence because of asymmetric division of accumulated damage among mother and daughter cells, accumulation of late acting deleterious mutations, or antagonistic pleiotropic effects....

  13. Optimizing the feeding operation of recombinant Escherichia coli ...

    African Journals Online (AJOL)

    Recombinant Escherichia coli BL21 was used to produce human-like collagen in fed-batch culture. After building and analyzing the kinetic models of fed-batch cultures, the maximum specific growth rate, Yx/s and Yp/s were 0.411 h-1 , 0.428 g·g-1 and 0.0716 g/g, respectively. The square error of cell growth models, glucose ...

  14. Identification and Functional Analysis of Escherichia coli Cysteine Desulfhydrases

    OpenAIRE

    Awano, Naoki; WADA, Masaru; Mori, Hirotada; Nakamori, Shigeru; Takagi, Hiroshi

    2005-01-01

    In Escherichia coli, three additional proteins having l-cysteine desulfhydrase activity were identified as O-acetylserine sulfhydrylase-A, O-acetylserine sulfhydrylase-B, and MalY protein, in addition to tryptophanase and cystathionine β-lyase, which have been reported previously. The gene disruption for each protein was significantly effective for overproduction of l-cysteine and l-cystine. Growth phenotype and transcriptional analyses suggest that tryptophanase contributes primarily to l-cy...

  15. Uji Aktivitas Antibakteri Ekstrak Herbal Terhadap Bakteri Escherichia Coli

    OpenAIRE

    Rahmawati, Nurina; Sudjarwo, Edhy; Widodo, Eko

    2014-01-01

    Several herbs have been evaluated as feed additive for chicken, namely tumeric, white tumeric, javanese ginger and black ginger. The purpose of the research was to examine antibacterial activity (inhibition diameter zone and minimum inhibition concentration test) on several herbs extract toward Escherichia coli. In the experiment, there were 6 treatments namely aquadest 100% (A0), antibiotic tetracycline (A1), tumeric extract (A2), white tumeric extract (A3), javanese ginger extract (A4) and ...

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

    Science.gov (United States)

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

    2014-07-18

    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.

  17. 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.

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

    Science.gov (United States)

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

    2014-01-01

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

  19. PROFILE OF RESISTANCE OF Escherichia coli ISOLATED FROM CANINE PYOMETRA

    Directory of Open Access Journals (Sweden)

    Fernanda Santana Oliveira

    2016-10-01

    Full Text Available The endothelial pyometra is a disease that affects more frequently reproductively active adult females. Characterized by inflammation and accumulation of exudate in the uterine cavity, generally associated with bacterial infections. The present study aimed to evaluate the resistance profile of Escherichia coli isolates from 42 female dogs diagnosed with pyometra, seen at the Department of Small Animal Surgery, Hospital of Veterinary Medicine, Federal University of Bahia. To perform the bacteriological analysis, a sample of the contents of the uterus was obtained immediately after surgery of ovariosalpingohisterectomy therapy (OSH and sent to the laboratory. Microbiological analysis showed a predominance of the bacterium Escherichia coli in 40.5% (15/37. Strains of Escherichia coli isolates showed higher rates of resistance to antimicrobial erythromycin (93.3 %, azithromycin (80 %, ampicillin, amoxicillin, and cephalothin (40% each. This study reinforces the need to perform the microbiological examination for epidemiological purposes and the correct therapeutic application, thereby avoiding the indiscriminate use of antimicrobials and the potential emergence of multidrug-resistant  strains. Keywords: bacteria; multiresistant;  uterus.

  20. [Integration and expression of sdh gene in Escherichia coli].

    Science.gov (United States)

    Gao, Shu-ying; Zhang, Wei-cai; Wang, Jian-hua; Guo, Ai-guang

    2005-02-01

    The chloramphenicol-resistant cassette with short shared sequences of ptsG gene on both ends was PCR-generated from plasmid pKF3 and ligated to pMD18-T to construct pMD18-PC. The sdh gene for sorbose dehydrogenase was generated from plasmid pQE60-SDH and inserted into pMD18-PC, then pMD18-PC-SDH was constructed. It was digested with Pvu II and the target fragment ptsG1-cat-sdh-ptsG2 was recovered and electroporated into Escherichia coli JM109/pKD46. Homologous-recombination between linear DNA cassettes and Escherichia coli chromosomes took place by Red recombination. The detection result showed that the integron JM109s was of sorbose dehydrogenase activity. The PCR products assay using the upstream and downstream sequences of ptsG gene as primers and JM109s genomic DNA as template, indicated that sdh gene had been integrated at the ptsG gene site in Escherichia coli.

  1. Occurrence of toxigenic Escherichia coli in raw milk cheese in Brazil Ocorrência de Escherichia coli toxigênica em queijo-de-minas frescal no Brasil

    OpenAIRE

    Paneto, B.R. [UNESP; Schocken-Iturrino, R.P.; Macedo,C.; Santo, E.; J.M. Marin

    2007-01-01

    The occurrence of toxigenic Escherichia coli in raw milk cheese was surveyed in Middle Western Brazil. Fifty samples of cheese from different supermarkets were analyzed for E.coli. The isolates were serotyped and screened for the presence of verotoxigenic E. coli (VTEC) and enterotoxigenic E. coli (ETEC) by Polymerase Chain Reaction (PCR). The susceptibility to thirteen antimicrobial agents was evaluated by the disk diffusion method. E.coli were recovered from 48 (96.0%) of the samples. The s...

  2. Identification and Molecular Characterization of Antimicrobial-Resistant Shiga Toxin–Producing Escherichia coli Isolated from Retail Meat Products

    OpenAIRE

    Li, Ming-Cheng; Wang, Fang; Li, Fan

    2011-01-01

    Ten (2.7%) Shiga toxin–producing Escherichia coli (STEC) were isolated from 370 samples of raw minced beef, mutton, pork, and chicken from the Jilin region of China; and additional 10 E. coli O157:H7 isolates were previously isolated from different Jilin regions. Seventeen of the isolates were multiresistant, exhibiting resistance to ampicillin, ciprofloxacin, tetracycline, sulfamethoxazole-trimethoprim, gentamycin, and streptomycin. Class 1 integrons were detected in nine (45.0%) of the STEC...

  3. 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...

  4. Antimicrobial resistance in Salmonella and Escherichia coli isolated from commercial shell eggs.

    Science.gov (United States)

    Musgrove, M T; Jones, D R; Northcutt, J K; Cox, N A; Harrison, M A; Fedorka-Cray, P J; Ladely, S R

    2006-09-01

    The development of antimicrobial resistance in bacteria has become a global problem. Isolates of Salmonella and Escherichia coli recovered from shell egg samples, collected at 3 commercial plants, were analyzed for resistance to 16 antimicrobial agents (n=990). Eggs were sampled by rinsing in a saline solution. Pooled samples were preenriched in buffered peptone water and then selectively isolated using standard broths and agars. Salmonella-positive isolates were serogrouped immunologically before being serotyped. Enterobacteriaceae were enumerated from individual samples using violet red bile glucose agar plates. Escherichia coli were identified biochemically from presumptive Enterobacteriaceae isolates. Salmonella and generic E. coli antimicrobial-susceptibility testing was conducted using a semiautomated broth microdilution system. More resistance was observed in the Salmonella isolates (n=41) than in the E. coli isolates (n=194). Salmonella Typhimurium was the most prevalent (69.0%) serotype and demonstrated the greatest multiple resistance. Salmonella Kentucky, the least prevalent (5.0%) serotype recovered, was the most susceptible. Although 34.1% of the Salmonella serotypes were susceptible to all antimicrobial agents, 60.1% were resistant to 11 or more compounds. Many Salmonella isolates exhibited resistance to tetracycline (63.4%), nalidixic acid (63.4%), and streptomycin (61.0%). Most E. coli isolates (73.2%) were susceptible to all antimicrobial drugs. Many E. coli isolates exhibited resistance to tetracycline (29.9%), streptomycin (6.2%), and gentamicin (3.1%). Only 1% of the E. coli isolates were resistant to 4 antimicrobial agents. These data indicate that shell eggs can harbor resistant foodborne and commensal bacteria; among Salmonella isolates, resistance was serotype-dependent.

  5. Ecological and genetic determinants of plasmid distribution in Escherichia coli.

    Science.gov (United States)

    Medaney, Frances; Ellis, Richard J; Raymond, Ben

    2016-11-01

    Bacterial plasmids are important carriers of virulence and antibiotic resistance genes. Nevertheless, little is known of the determinants of plasmid distribution in bacterial populations. Here the factors affecting the diversity and distribution of the large plasmids of Escherichia coli were explored in cattle grazing on semi-natural grassland, a set of populations with low frequencies of antibiotic resistance genes. Critically, the population genetic structure of bacterial hosts was chararacterized. This revealed structured E. coli populations with high diversity between sites and individuals but low diversity within cattle hosts. Plasmid profiles, however, varied considerably within the same E. coli genotype. Both ecological and genetic factors affected plasmid distribution: plasmid profiles were affected by site, E. coli diversity, E. coli genotype and the presence of other large plasmids. Notably 3/26 E. coli serotypes accounted for half the observed plasmid-free isolates indicating that within species variation can substantially affect carriage of the major conjugative plasmids. The observed population structure suggest that most of the opportunities for within species plasmid transfer occur between different individuals of the same genotype and support recent experimental work indicating that plasmid-host coevolution, and epistatic interactions on fitness costs are likely to be important in determining occupancy. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Transformation of Escherichia coli and protein expression using lipoplex mimicry.

    Science.gov (United States)

    Yun, Chul-Ho; Bae, Chun-Sik; Ahn, Taeho

    2016-11-01

    We investigated a "one-step" method for transformation of and protein expression in Escherichia coli (E. coli) using a complex of n-stearylamine, a cationic lipid, and plasmid DNA, which mimics lipoplex-based approaches. When E. coli cells were treated with the cationic lipid-plasmid complex, the transformation efficiencies were in the range of approximately 2-3 × 10(6) colony-forming units. Further increase in the efficiency was obtained by co-treatment with calcium chloride (or rubidium chloride) and the complexes. Moreover, after DNA transfer, E. coli cells successfully expressed plasmid-encoded proteins such as cytochrome P450s and glutathione-S-transferase without overnight incubation of the cells to form colonies, an indispensable step in other bacterial transformation methods. In this study, we provide a simple method for E. coli transformation, which does not require the preparation of competent cells. The present method also shortens the overall procedures for transformation and gene expression in E. coli by omitting the colony-forming step. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Production of 3-O-xylosyl quercetin in Escherichia coli

    DEFF Research Database (Denmark)

    Pandey, Ramesh Prasad; Malla, Sailesh; Simkhada, Dinesh

    2013-01-01

    Quercetin, a flavonol aglycone, is one of the most abundant flavonoids with high medicinal value. The bioavailability and pharmacokinetic properties of quercetin are influenced by the type of sugars attached to the molecule. To efficiently diversify the therapeutic uses of quercetin, Escherichia...... coli was harnessed as a production factory by the installation of various plant and bacterial UDP-xylose sugar biosynthetic genes. The genes encoding for the UDP-xylose pathway enzymes phosphoglucomutase (nfa44530), glucose-1-phosphate uridylyltransferase (galU), UDP-glucose dehydrogenase (calS8......), and UDP-glucuronic acid decarboxylase (calS9) were overexpressed in E. coli BL21 (DE3) along with a glycosyltransferase (arGt-3) from Arabidopsis thaliana. Furthermore, E. coli BL21(DE3)/∆pgi, E. coli BL21(DE3)/∆zwf, E. coli BL21(DE3)/∆pgi∆zwf, and E. coli BL21(DE3)/∆pgi∆zwf∆ushA mutants carrying...

  8. Bactericidal activity of ciprofloxacin upon Escherichia coli and Acinetobacter baumanni.

    Science.gov (United States)

    Zemelman, R; Vejar, C; Bello, H; Domínguez, M; González, G

    1992-01-01

    The mechanisms of bactericidal activity of ciprofloxacin (mechanisms A and B) upon cells of a strain of Escherichia coli and one strain of Acinetobacter baumannii were investigated under different conditions. The killing of E. coli cells by ciprofloxacin was significantly reduced by chloramphenicol, but this antibiotic showed almost no activity upon killing of A. baumannii cells by this quinolone. Similar results were obtained when rifampicin was added to ciprofloxacin. Bactericidal activity of ciprofloxacin upon nondividing cells of E. coli was lower and that upon non-dividing cells of A. baumannii was not affected when compared with activity of ciprofloxacin upon dividing cells of both microorganisms. These results demonstrate that the antibacterial activity of ciprofloxacin upon A. baumannii is independent of protein and ARN synthesis, a fact which suggests that this quinolone exerts only bactericidal mechanism B upon A. baumannii. This finding might explain, at least in part, the lower susceptibility of this microorganism to ciprofloxacin.

  9. 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.

  10. 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 of time...

  11. Reassessing Escherichia coli as a cell factory for biofuel production.

    Science.gov (United States)

    Wang, Chonglong; Pfleger, Brian F; Kim, Seon-Won

    2017-06-01

    Via metabolic engineering, industrial microorganisms have the potential to convert renewable substrates into a wide range of biofuels that can address energy security and environmental challenges associated with current fossil fuels. The user-friendly bacterium, Escherichia coli, remains one of the most frequently used hosts for demonstrating production of biofuel candidates including alcohol-, fatty acid- and terpenoid-based biofuels. In this review, we summarize the metabolic pathways for synthesis of these biofuels and assess enabling technologies that assist in regulating biofuel synthesis pathways and rapidly assembling novel E. coli strains. These advances maintain E. coli's position as a prominent host for developing cell factories for biofuel production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. EcoProDB: the Escherichia coli protein database.

    Science.gov (United States)

    Yun, Hongseok; Lee, Jeong Wook; Jeong, Joonwoo; Chung, Jaesung; Park, Jong Myoung; Myoung, Han Na; Lee, Sang Yup

    2007-09-15

    EcoProDB is a web-based database for comparative proteomics of Escherichia coli. The database contains information on E. coli proteins identified on 2D gels along with other resources collected from various databases and published literature, with a special feature of showing the expression levels of E. coli proteins under different genetic and environmental conditions. It also provides comparative information of subcellular localization, theoretical 2D map, experimental 2D map and integrated protein information via an interactive web interface and application such as the Map Browser. Users can also upload their own 2D gels, extract core information associated with the proteins and 2D gel results from different experiments and consequently generate new knowledge and hypotheses for further studies. EcoProDB database system is accessible at http://eecoli.kaist.ac.kr.

  13. Increased detection of extended spectrum beta-lactamase producing Salmonella enterica and Escherichia coli isolates from poultry

    NARCIS (Netherlands)

    Dierikx, C.M.; Essen-Zandbergen, van A.; Veldman, K.T.; Smith, H.E.; Mevius, D.J.

    2010-01-01

    To gain more information on the genetic basis of the rapid increase in the number of isolates exhibiting non-wild type Minimum Inhibitory Concentrations (MICs) for cefotaxime observed since 2003, beta-lactamase genes of 22 Salmonella enterica and 22 Escherichia coli isolates from broilers in 2006

  14. Molecular profiling: Catecholamine modulation of gene expression in Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium

    Science.gov (United States)

    Investigations of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium have demonstrated that these bacterial pathogens can respond to the presence of catecholamines including norepinephrine and/or epinephrine in their environment by modulating gene expression and exhibiting various ...

  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.......5% of the strains as belonging to the WT population, since this proportion of strains harbored resistance genes and exhibited MICs ≤32 mg/L. Out of 208 E. coli strains, 80 (38.5%) tested positive for aadA (n = 69), strA (n = 18), and strB (n = 31). Of the E. coli isolates exhibiting MICs of 4 mg/L, 8 mg/L, 16 mg....../L, and 32 mg/L, 3.6%, 17.6%, 53%, and 82.3%, respectively, harbored any of the three genes. Based on the European Committee on Antimicrobial Susceptibility Testing guidelines (ECOFF ≤16 mg/L), 25% of the E. coli strains presenting MIC ≤16 mg/L would have been incorrectly categorized as belonging to the WT...

  16. FREQUENCY AND DISTRIBUTION OF DIARRHOEAGENIC ESCHERICHIA COLI STRAINS ISOLATED FROM PEDIATRIC PATIENTS WITH DIARRHOEA IN BOSNIA AND HERZEGOVINA

    OpenAIRE

    Dedeić-Ljubović, AmeLa; Hukić, Mirsada; Bekić, DaRia; Zvizdić, AmrA

    2009-01-01

    Diarrhoeal disease is a major cause of illness and death among infants and young children worldwide. Among the Escherichia coli (E. coli) causing intestinal diseases, there are six well-described categories: enteroaggregative E. coli (EAEC), diffusely adherent E. coli (DAEC), enteroinvasive E. coli (EIEC), entero-pathogenic E. coli (EPEC), enterohaemorrhagic E. coli (EHEC) and enterotoxigenic E. coli (ETEC).

  17. Biosynthesis, purification and characterization of silver nanoparticles using Escherichia coli.

    Science.gov (United States)

    Gurunathan, Sangiliyandi; Kalishwaralal, Kalimuthu; Vaidyanathan, Ramanathan; Venkataraman, Deepak; Pandian, Sureshbabu Ram Kumar; Muniyandi, Jeyaraj; Hariharan, Nellaiah; Eom, Soo Hyun

    2009-11-01

    The application of nanoscale materials and structures, usually ranging from 1 to 100 nanometers (nm), is an emerging area of nanoscience and nanotechnology. Nanomaterials may provide solutions to technological and environmental challenges in the areas of solar energy conversion, catalysis, medicine, and water-treatment. The development of techniques for the controlled synthesis of nanoparticles of well-defined size, shape and composition, to be used in the biomedical field and areas such as optics and electronics, has become a big challenge. Development of reliable and eco-friendly processes for synthesis of metallic nanoparticles is an important step in the field of application of nanotechnology. One of the options to achieve this objective is to use 'natural factories' such as biological systems. This study reports the optimal conditions for maximum synthesis of silver nanoparticles (AgNPs) through reduction of Ag(+) ions by the culture supernatant of Escherichia coli. The synthesized silver nanoparticles were purified by using sucrose density gradient centrifugation. The purified sample was further characterized by UV-vis spectra, fluorescence spectroscopy and TEM. The purified solution yielded the maximum absorbance peak at 420 nm and the TEM characterization showed a uniform distribution of nanoparticles, with an average size of 50 nm. X-ray diffraction (XRD) spectrum of the silver nanoparticles exhibited 2theta values corresponding to the silver nanocrystal. The size-distribution of nanoparticles was determined using a particle-size analyzer and the average particle size was found to be 50 nm. This study also demonstrates that particle size could be controlled by varying the parameters such as temperature, pH and concentration of AgNO(3).

  18. Inhibition of Escherichia coli in cultivated cattle manure.

    Science.gov (United States)

    Weinberg, Z G; Szakacs, G; Chen, Y; Pinto, R; Bernstein, S; Konya, B; Sela Saldinger, S

    2014-05-01

    A common practice on Israeli dairy barns comprises daily cultivation of the manure. Cultivation is a mechanical process used to break up and till the manure bedding and it results in a drier and aerated bedding and cleaner cows, which consequently reduces the incidence of mastitis. Cultivation was associated with a shorter survival of Escherichia coli in cultivated manure as compared with noncultivated manure. The objective of the current study was to elucidate the mechanism responsible for the shorter survival duration of E. coli in the cultivated manure. We hypothesized that microorganisms that are antagonistic to E. coli, developing in the cultivated manure, are responsible for this phenomenon. A cow manure derived E. coli strain expressing the green fluorescence protein and antibiotic resistance markers was used to inoculate cow manure in 1.5-L jars. Manure treatments included cultivated and noncultivated manure. Half the jars of each cultivation treatment were autoclave sterilized at 121°C for 1 h on 3 successive days to eliminate from the manure antagonistic microorganisms. Each cultivation-sterilization treatment was performed in triplicate jars. Following sterilization, E. coli numbers in the cultivated and noncultivated manure were comparable, while in the nonsterilized manure the numbers were lower in the cultivated compared with the noncultivated manure. Several fungi isolated from the cultivated manure samples displayed inhibition effect on the tagged E. coli. Antagonistic fungi were also isolated from large-scale cultivated manure samples collected on several dairy farms in Israel. These findings support the notion that manure cultivation might facilitate the development of microorganisms that are antagonistic to E. coli, thus contributing to the general hygiene of the cattle. Identifying the mechanisms by which the antagonistic fungi affect the survival of E. coli in manure could be exploited for improvement of the animal health and for limiting the

  19. Protective effects of indigenous Escherichia coli against a pathogenic E. coli challenge strain in pigs.

    Science.gov (United States)

    Vahjen, W; Cuisiniere, T; Zentek, J

    2017-10-13

    To investigate the inhibitory effect of indigenous enterobacteria on pathogenic Escherichia coli, a challenge trial with postweaning pigs was conducted. A pathogenic E. coli strain was administered to all animals and their health was closely monitored thereafter. Faecal samples were taken from three healthy and three diarrhoeic animals. Samples were cultivated on MacConkey agar and isolates were subcultured. A soft agar overlay assay was used to determine the inhibitory activity of the isolates. A total of 1,173 enterobacterial isolates were screened for their ability to inhibit the E. coli challenge strain. Colony forming units of enterobacteria on MacConkey agar were not different between healthy and diarrhoeic animals in the original samples. Furthermore, numbers of isolates per animal were also not significantly different between healthy (482 isolates) and diarrhoeic animals (691 isolates). A total of 43 isolates (3.7%) with inhibitory activity against the pathogenic E. coli challenge strain were detected. All inhibitory isolates were identified as E. coli via MALDI-TOF. The isolates belonged to the phylotypes A, C and E. Many isolates (67.4%) were commensal E. coli without relevant porcine pathogenic factors, but toxin- and fimbrial genes (stx2e, fae, estIb, elt1a, fas, fan) were detected in 14 inhibitory isolates. Healthy animals showed significantly (P=0.003) more inhibitory isolates (36 of 482 isolates; 7.5%) than diseased animals (7 of 691 isolates; 1.0%). There were no significant correlations regarding phylotype or pathogenic factors between healthy and diseased animals. This study has shown that a small proportion of indigenous E. coli is able to inhibit in vitro growth of a pathogenic E. coli strain in pigs. Furthermore, healthy animals possess significantly more inhibitory E. coli strains than diarrhoeic animals. The inhibition of pathogenic E. coli by specific indigenous E. coli strains may be an underlying principle for the containment of pathogenic

  20. Jumlah Bakteri Coliform dan Deteksi Escherichia Coli pada Daging Ayam di Pekanbaru

    OpenAIRE

    Juwita, Usna; Haryani, Yuli; Jose, Christine

    2014-01-01

    Coliform bacteria are often referred as indicator organisms to indicate the potential presence of disease-causing bacteria. Escherichia coli is a type of Coliform bacteria. Most Escherichia coli are harmless and commonly found in the intestines of humans and animals. However, some strains can cause illness. Coliform bacteria and Escherichia coli contamination in chicken could be detected using Most Probable Number (MPN) multi-step assay which consists of presumptive, confirmed, and completed ...

  1. The resistance to chemotherapeutic agents of Escherichia coli from domestic dogs and cats.

    Science.gov (United States)

    Moss, S; Frost, A J

    1984-03-01

    The prevalence of antibiotic resistant Escherichia coli in the rectal flora of 168 healthy dogs and 93 cats in the Brisbane area was investigated. Rectal swabs were plated on MacConkey agar with and without antibiotics, and 690 isolates confirmed as faecal E. coli were tested for resistance to tetracycline, streptomycin, chloramphenicol, ampicillin, neomycin, furazolidone and sulphanilamide. Resistant isolates were obtained from 101 (60%) of the dogs and 24 (26%) of the cats sampled. A high percentage of the isolates was resistant to tetracycline, streptomycin, ampicillin and sulphanilamide. Multiple resistance to 3 or more of the drugs was exhibited by the majority of isolates and a total of 31 different multiple resistance patterns was demonstrated. Of the 50 strains tested for transfer of resistance, 30 (60%) transferred some or all of their resistance determinants to an E. coli K12F - recipient.

  2. Cd(II) and As(III) bioaccumulation by recombinant Escherichia coli expressing oligomeric human metallothioneins.

    Science.gov (United States)

    Ma, Yao; Lin, Jianqun; Zhang, Chengjia; Ren, Yilin; Lin, Jianqiang

    2011-01-30

    Metallothioneins (MTs) are a family of metal binding proteins. Recombinant Escherichia coli expressing the human MT (hMT-1A) gene was constructed for bioaccumulation of heavy metals. In order to increase protein stability, the glutathione S-transferase (GST) gene was fused with the hMT-1A gene and coexpressed. In order to increase MT expression efficiency and metal binding capacity, two, three or four hMT-1A genes were integrated in series and overexpressed in E. coli. The recombinant E. coli expressing the GST fused trimeric hMT-1A protein exhibited the highest Cd(II) and As(III) bioaccumulation ability, 6.36 mg Cd/g dry cells and 7.59 mg As/g dry cells, respectively. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. The Origin of Bacterial Resistance to Proflavine: 5. Transformation of Proflavine Resistance in Escherichia coli

    National Research Council Canada - National Science Library

    SINAI, JEHUDITH; YUDKIN, J

    1959-01-01

    ...: We attempted to transform proflavine-sensitive strains of Escherichia coli to proflavine resistance by growth in the presence of deoxyribonucleic acid-containing extracts from resistant organisms...

  4. THE WIDESPREAD OCCURRENCE OF THE ENTEROHEMOLYSIN GENE EHLYA AMONG ENVIRONMENTAL STRAINS OF ESCHERICHIA COLI

    Science.gov (United States)

    The putative virulence factor enterohemolysin, encoded for by the ehlyA gene, has been closely associated with the pathogenic enterohemorrhagic Escherichia coli (EHEC) group. E. coli isolates from effluents from seven geographically dispersed municipal ...

  5. Escherichia coli β-Lactamases: What Really Matters

    Science.gov (United States)

    Bajaj, Priyanka; Singh, Nambram S.; Virdi, Jugsharan S.

    2016-01-01

    Escherichia coli strains belonging to diverse pathotypes have increasingly been recognized as a major public health concern. The β-lactam antibiotics have been used successfully to treat infections caused by pathogenic E. coli. However, currently, the utility of β-lactams is being challenged severely by a large number of hydrolytic enzymes – the β-lactamases expressed by bacteria. The menace is further compounded by the highly flexible genome of E. coli, and propensity of resistance dissemination through horizontal gene transfer and clonal spread. Successful management of infections caused by such resistant strains requires an understanding of the diversity of β-lactamases, their unambiguous detection, and molecular mechanisms underlying their expression and spread with regard to the most relevant information about individual bacterial species. Thus, this review comprises first such effort in this direction for E. coli, a bacterial species known to be associated with production of diverse classes of β-lactamases. The review also highlights the role of commensal E. coli as a potential but under-estimated reservoir of β-lactamases-encoding genes. PMID:27065978

  6. Escherichia coli ST131, an intriguing clonal group.

    Science.gov (United States)

    Nicolas-Chanoine, Marie-Hélène; Bertrand, Xavier; Madec, Jean-Yves

    2014-07-01

    In 2008, a previously unknown Escherichia coli clonal group, sequence type 131 (ST131), was identified on three continents. Today, ST131 is the predominant E. coli lineage among extraintestinal pathogenic E. coli (ExPEC) isolates worldwide. Retrospective studies have suggested that it may originally have risen to prominence as early as 2003. Unlike other classical group B2 ExPEC isolates, ST131 isolates are commonly reported to produce extended-spectrum β-lactamases, such as CTX-M-15, and almost all are resistant to fluoroquinolones. Moreover, ST131 E. coli isolates are considered to be truly pathogenic, due to the spectrum of infections they cause in both community and hospital settings and the large number of virulence-associated genes they contain. ST131 isolates therefore seem to contradict the widely held view that high levels of antimicrobial resistance are necessarily associated with a fitness cost leading to a decrease in pathogenesis. Six years after the first description of E. coli ST131, this review outlines the principal traits of ST131 clonal group isolates, based on the growing body of published data, and highlights what is currently known and what we need to find out to provide public health authorities with better information to help combat ST131. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  7. Escherichia coli ST131, an Intriguing Clonal Group

    Science.gov (United States)

    Bertrand, Xavier; Madec, Jean-Yves

    2014-01-01

    SUMMARY In 2008, a previously unknown Escherichia coli clonal group, sequence type 131 (ST131), was identified on three continents. Today, ST131 is the predominant E. coli lineage among extraintestinal pathogenic E. coli (ExPEC) isolates worldwide. Retrospective studies have suggested that it may originally have risen to prominence as early as 2003. Unlike other classical group B2 ExPEC isolates, ST131 isolates are commonly reported to produce extended-spectrum β-lactamases, such as CTX-M-15, and almost all are resistant to fluoroquinolones. Moreover, ST131 E. coli isolates are considered to be truly pathogenic, due to the spectrum of infections they cause in both community and hospital settings and the large number of virulence-associated genes they contain. ST131 isolates therefore seem to contradict the widely held view that high levels of antimicrobial resistance are necessarily associated with a fitness cost leading to a decrease in pathogenesis. Six years after the first description of E. coli ST131, this review outlines the principal traits of ST131 clonal group isolates, based on the growing body of published data, and highlights what is currently known and what we need to find out to provide public health authorities with better information to help combat ST131. PMID:24982321

  8. Recent Advances in Understanding Enteric Pathogenic Escherichia coli

    Science.gov (United States)

    Croxen, Matthew A.; Law, Robyn J.; Scholz, Roland; Keeney, Kristie M.; Wlodarska, Marta

    2013-01-01

    SUMMARY Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli. PMID:24092857

  9. Verotoxigenic Escherichia coli (VTEC isolated from cow milk

    Directory of Open Access Journals (Sweden)

    Widodo Suwito

    2016-01-01

    Full Text Available Verotoxigenic Escherichia coli (VTEC strains are responsible for serious human illnesses. These strains are commonly found in milk. The aim of this study was to determine the occurrence of verotoxigenic E. coli in milk. A total of 351 milk samples, were collected from dairy farms in Bogor, Sukabumi and Cianjur. These samples were analyzed for VTEC using biochemical, serological and vero cell cytotoxicity assays. VTEC O157:H7 isolates were found in milk collected from dairy herds in Bogor and Sukabumi at rates 0.47% of 214 samples, 1.10% of 91 samples respectively, and none in Cianjur. Hemolytic E. coli isolates were found in 0.94% of 214 milk samples from Bogor, 2.2% of 91 milk samples from Sukabumi and none from Cianjur. From E. coli isolates, 53 isolates (67.95% were verotoxigenic, consisted of: two E. coli O157:H7 isolates and 51 non O157:H7 isolates.Therefore this study showed the occurrence of VTEC in milk samples from dairy farms in Bogor, Sukabumi and Cianjur.

  10. Serotypes of Escherichia coli in sudden infant death syndrome.

    Science.gov (United States)

    Pearce, J L; Bettelheim, K A; Luke, R K J; Goldwater, P N

    2010-02-01

    To examine the diversity of Escherichia coli serotypes found in the intestinal contents of infants who died of Sudden Infant Death Syndrome (SIDS) compared with that in comparison infants. Over the 3-year period, 1989-1991, in South Australia and Victoria (Australia), a total of 687 E. coli isolates from 231 patients with SIDS (348 isolates), 98 infants who had died from other causes (144 isolates) and 160 healthy infants (195 isolates) were studied. The isolates from patients with SIDS were found to represent 119 different serotypes; the isolates from 'other cause' infants represent 97 different serotypes; and the isolates from healthy infants represent 117 different serotypes. The seven common serotypes isolated most frequently from infants with SIDS belonged to those associated with extra-intestinal infections in humans. Compared to healthy infants (6%), these were found in significantly higher proportions among infants who died of other causes (13%, P < 0.05) or infants with SIDS (18.7%, P = 0.0002). Despite these sources yielding a wide variety of serotypes of E. coli, a pattern of certain potential pathotypes of E. coli being associated with SIDS is apparent. While SIDS remains one of the most important diagnoses of postneonatal death, its causes are still unexplained. If E. coli has a role in the pathogenesis of SIDS (as suggested by the pathotypes identified on the basis of serotype), further studies may reveal novel virulence factors that may clarify the role of this bacterium in SIDS.

  11. Escherichia coli mediated urinary tract infections: are there distinct uropathogenic E. coli (UPEC) pathotypes?

    Science.gov (United States)

    Marrs, Carl F; Zhang, Lixin; Foxman, Betsy

    2005-11-15

    A variety of virulence genes are associated with Escherichia coli mediated urinary tract infections. Particular sets of virulence factors shared by bacterial strains directing them through a particular pathogenesis process are called a "pathotype." Comparison of co-occurrence of potential urinary tract infection (UTI) virulence genes among different E. coli isolates from fecal and UTI collections provides evidence for multiple pathotypes of uropathogenic E. coli, but current understanding of critical genetic differences defining the pathotypes is limited. Discovery of additional E. coli genes involved in uropathogenesis and determination of their distribution and co-occurrences will further define UPEC pathotypes and allow for a more detailed analysis of how these pathotypes might differ in how they cause disease.

  12. AN ESCHERICHIA-COLI STRAIN DEFICIENT FOR BOTH EXONUCLEASE-V AND DEOXYCYTIDINE TRIPHOSPHATE DEAMINASE SHOWS ENHANCED SENSITIVITY TO IONIZING-RADIATION

    NARCIS (Netherlands)

    ESTEVENON, AM; KOOISTRA, J; SICARD, N

    1995-01-01

    An Escherichia coli mutant lacking deoxycytidine triphosphate deaminase (Dcd) activity and an unknown function encoded by a gene designated ior exhibits sensitivity to ionizing radiation whereas dcd mutants themselves are not sensitive. A DNA fragment from an E. coli genomic library that restores

  13. 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.

  14. Kemampuan Antibakteri Susu Fermentasi terhadap Escherichia coli dan Shigella

    Directory of Open Access Journals (Sweden)

    Zuraida Hanum

    2017-04-01

    ABSTRACT. The study was performed using Lactobacillus plantarum as starter at concentrations of 3%, 4% and 5% and incubated for 48 hours at room temperature. Observation of fermented milk conducted for 8 day. The antibacterial activity test was analyzed to find whether fermented milk able to  inhibit pathogen growth. The antibacterial ability of suppressing of Enterobacteriaceae growth  observed by using Escherichia coli and Shigella flexneri (106 CFU/ml in Nutrient Agar and challenge to fermented milk using 3%, 4% and 5% starter or about (50 µl/well. Further testing of microbial inhibitory activity of fermented milk against pathogenic bacteria conducted by three replications. The data obtained were analyzed statistically using ANOVA. The results showed that the ability of fermented milk as antibacterial on Escherichia coli and Shigella flexneri occurred in the amount of sell as much as (106 CFU / ml when it grown in nutrient agar. As a conclusion,  fermented milk using a 5% starter showed that the highest inhibition zone of 17.42 mm to E. coli on the second day observation. While  inhibition zone of  Shigella flexnerii was 8.88 mm on the third day with the same starter concentration.

  15. Isolation and characterization of lytic bacteriophages against enterohaemorrhagic Escherichia coli.

    Science.gov (United States)

    Viazis, S; Akhtar, M; Feirtag, J; Brabban, A D; Diez-Gonzalez, F

    2011-05-01

     The objective of this study was to isolate, identify and characterize a collection of lytic bacteriophages capable of infecting enterohaemorrhagic Escherichia coli (EHEC) serotypes. Phages were isolated from dairy and cattle feedlot manure using E. coli O157, O26 and O111 strains as hosts. Phages were enriched from faecal slurries by culture in 10× trypticase soy broth at 37°C overnight. Phage plaques were obtained by mixing the filtered culture supernatant with molten tryptone agar containing the phage E. coli host strain, pouring the inoculated agar on top of cooled TS agar and incubating the culture overnight. Phages were purified from plaques and screened against additional E. coli and EHEC strains by the efficiency of plating method (EOP). Phage CEV2, and five other phages previously isolated, were able to lyse all of the 15 O157 strains tested with EOP values consistently above 0·001. Two phages were found to be highly effective against strains of E. coli O157 through EOP tests and against O26 strains through spot tests, but not against the O serogroup 111 strains. A cocktail of eight phage that lyse E. coli O157 strains resulted in >5 log CFU ml(-1) reductions at 37°C. Multiplex-PCR revealed that none of these eight phages carried stx1, stx2, hlyA or eaeA genes. A cocktail of bacteriophages was capable of lysing most strains of two EHEC serotypes. This collection of phages can be combined and potentially used as an antimicrobial cocktail to inactivate E. coli strains from O serogroups 157 and 26 and reduce their incidence in the food chain. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

  16. Attaching and effacing Escherichia coli isolates from Danish children: clinical significance and microbiological characteristics

    DEFF Research Database (Denmark)

    Jensen, C; Ethelberg, S; Olesen, B

    2007-01-01

    This study describes the prevalence, clinical manifestations and microbiological characteristics of attaching and effacing Escherichia coli isolates, i.e., enteropathogenic E. coli (EPEC) belonging to the classical EPEC serotypes, non-EPEC attaching and effacing E. coli (A/EEC) and verocytotoxin......-producing E. coli (VTEC), isolated in a case-control study of Danish children aged

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

    Science.gov (United States)

    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. PMID:15071051

  18. Escherichia coli type III secretion system 2 (ETT2) is widely distributed in avian pathogenic Escherichia coli isolates from Eastern China.

    Science.gov (United States)

    Wang, S; Liu, X; Xu, X; Zhao, Y; Yang, D; Han, X; Tian, M; Ding, C; Peng, D; Yu, S

    2016-10-01

    Pathogens utilize type III secretion systems to deliver effector proteins, which facilitate bacterial infections. The Escherichia coli type III secretion system 2 (ETT2) which plays a crucial role in bacterial virulence, is present in the majority of E. coli strains, although ETT2 has undergone widespread mutational attrition. We investigated the distribution and characteristics of ETT2 in avian pathogenic E. coli (APEC) isolates and identified five different ETT2 isoforms, including intact ETT2, in 57·6% (141/245) of the isolates. The ETT2 locus was present in the predominant APEC serotypes O78, O2 and O1. All of the ETT2 loci in the serotype O78 isolates were degenerate, whereas an intact ETT2 locus was mostly present in O1 and O2 serotype strains, which belong to phylogenetic groups B2 and D, respectively. Interestingly, a putative second type III secretion-associated locus (eip locus) was present only in the isolates with an intact ETT2. Moreover, ETT2 was more widely distributed in APEC isolates and exhibited more isoforms compared to ETT2 in human extraintestinal pathogenic E. coli, suggesting that APEC might be a potential risk to human health. However, there was no distinct correlation between ETT2 and other virulence factors in APEC.

  19. Antibacterial evaluation of Salvia miltiorrhizae on Escherichia coli by microcalorimetry coupled with chemometrics.

    Science.gov (United States)

    Ying, Guangyao; Zhang, Shanshan; Hu, Yuli; Yang, Meihua; Chen, Ping; Wu, Xiaoru; Guo, Weiying; Kong, Weijun

    2017-12-01

    For seeking novel antibacterial agents with high efficacy and low toxicity to deal with drug resistance, the effects of Salvia miltiorrhizae from various sources on Escherichia coli were evaluated by microcalorimetry coupled with chemometrics. Firstly, the heat-flow power-time curves of E. coli growth affected by different S. miltiorrhizae samples were recorded. Then, some crucial quantitative thermo-kinetic parameters including growth rate constant, heat-flow power and heat output, etc. were obtained from theses curves and were further investigated by some powerful chemometric techniques including similarity analysis, multivariate analysis of variance, hierarchical clustering analysis and principle component analysis. By analyzing the principle parameters, growth rate constant of the second exponential phase (k 2) and the heat-flow output powers of the second highest peak (P 2), together with the derived parameter inhibitory ratio (I,  %), it could be quickly concluded that the tested S. miltiorrhizae samples from different sources in China exhibited strong antibacterial effects on E. coli and the samples from Beijing city exhibited the strongest anti-E. coli effects, which might be used as novel and underlying antibacterial candidates for the resistance of E. coli to the existing drugs in practice. This study provides a useful tool and helpful idea to accurately and rapidly evaluate the antibacterial effects of some complex matrices, offering some references for exploring new antibacterial agents.

  20. Polysorbates prevent biofilm formation and pathogenesis of Escherichia coli O104:H4.

    Science.gov (United States)

    Sloup, Rudolph E; Cieza, Roberto J; Needle, David B; Abramovitch, Robert B; Torres, Alfredo G; Waters, Christopher M

    2016-10-01

    Escherichia coli biotype O104:H4 recently caused the deadliest E. coli outbreak ever reported. Based on prior results, it was hypothesized that compounds inhibiting biofilm formation by O104:H4 would reduce its pathogenesis. The nonionic surfactants polysorbate 80 (PS80) and polysorbate 20 (PS20) were found to reduce biofilms by ≥ 90% at submicromolar concentrations and elicited nearly complete dispersal of preformed biofilms. PS80 did not significantly impact in vivo colonization in a mouse infection model; however, mice treated with PS80 exhibited almost no intestinal inflammation or tissue damage while untreated mice exhibited robust pathology. As PS20 and PS80 are classified as 'Generally Recognized as Safe' (GRAS) compounds by the Food and Drug Administration (FDA), these compounds have clinical potential to treat future O104:H4 outbreaks.

  1. Cellulose based nanofabrication; immobilization of silver nanoparticales and its size effect against Escherichia coli

    Science.gov (United States)

    Kalwar, Kaleemullah; Aqeel Bhutto, Muhammad; Dali, Li; Shan, Dan

    2017-10-01

    Herein, cellulose acetate nanofibers were manufactured by electrospinning technique and hydrolyzed by alkaline hydrolysis. Size effect of AgNPs was observed against E. coli. The structure and composition of nanofibers were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR) and Thermal behavior was analyzed by thermogravimetric analyzer (TGA). Furthermore, AgNPs were incorporated on deacetylated nanofibers and then oxidized by KMnO4. AgNPs decorated cellulose nanofibers exhibiting strong bactericide activity against Escherichia coli BH5α. Smaller in size 16.69 nm exhibited higher inhibition activity as compared to larger size 42.33 nm of AgNPs. It was shown that size of AgNPs has an effect on antimicrobial activity.

  2. Measuring the Viscosity of the Escherichia coli Plasma Membrane Using Molecular Rotors.

    Science.gov (United States)

    Mika, Jacek T; Thompson, Alexander J; Dent, Michael R; Brooks, Nicholas J; Michiels, Jan; Hofkens, Johan; Kuimova, Marina K

    2016-10-04

    The viscosity is a highly important parameter within the cell membrane, affecting the diffusion of small molecules and, hence, controlling the rates of intracellular reactions. There is significant interest in the direct, quantitative assessment of membrane viscosity. Here we report the use of fluorescence lifetime imaging microscopy of the molecular rotor BODIPY C10 in the membranes of live Escherichia coli bacteria to permit direct quantification of the viscosity. Using this approach, we investigated the viscosity in live E. coli cells, spheroplasts, and liposomes made from E. coli membrane extracts. For live cells and spheroplasts, the viscosity was measured at both room temperature (23°C) and the E. coli growth temperature (37°C), while the membrane extract liposomes were studied over a range of measurement temperatures (5-40°C). At 37°C, we recorded a membrane viscosity in live E. coli cells of 950 cP, which is considerably higher than that previously observed in other live cell membranes (e.g., eukaryotic cells, membranes of Bacillus vegetative cells). Interestingly, this indicates that E. coli cells exhibit a high degree of lipid ordering within their liquid-phase plasma membranes. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  3. Alkyl substituent effect on photosensitized inactivation of Escherichia coli by pyridinium-bonded P-porphyrins.

    Science.gov (United States)

    Matsumoto, Jin; Suemoto, Yusaku; Kanemaru, Hiroki; Takemori, Kyosuke; Shigehara, Masato; Miyamoto, Akari; Yokoi, Haruhiko; Yasuda, Masahide

    2017-03-01

    Activity of singlet oxygen sensitizers for photoinactivation of bacteria and photodynamic therapy of tumor cells has been evaluated using nonpathogenic model cells, such as Escherichia coli, Saccharomyces cerevisiae, and HeLa cells. Among them, E. coli, gram-negative bacterium, has complex membrane structures in the cell wall, resulting in an impermeable barrier to antimicrobial agents. Therefore, few singlet oxygen sensitizers have photoinactivation activities toward E. coli at low concentrations. Recently polycationic porphyrins have received much attention as a new type of singlet oxygen sensitizers because they have strong binding affinities for DNA and proteins. Here, we prepared 13 types of di- and tricationic P- and Sb-porphyrin sensitizers substituted with the N-alkylpyridinium (APy) group at the axial ligand or the meso position to examine their bactericidal activity toward E. coli under visible-light irradiation. Photobactericidal activities were evaluated using half-life (T1/2 in min) of E. coli and minimum effective concentrations of the porphyrin sensitizers. Di-cationic P-porphyrins containing the Apy group at meso position exhibited bactericidal activity under dark conditions. Tricationic porphyrins showed a higher bactericidal activity than monocationic porphyrins. It was found that the bactericidal activity depended on the alkyl chain length of APy. Tricationic porphyrin with N-heptylpyridinium in two axial ligands was the most reactive for the photoinactivation of E. coli. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Development of functionalised polyelectrolyte capsules using filamentous Escherichia coli cells

    Directory of Open Access Journals (Sweden)

    Lederer Franziska L

    2012-12-01

    Full Text Available Abstract Background Escherichia coli is one of the best studied microorganisms and finds multiple applications especially as tool in the heterologous production of interesting proteins of other organisms. The heterologous expression of special surface (S- layer proteins caused the formation of extremely long E. coli cells which leave transparent tubes when they divide into single E. coli cells. Such natural structures are of high value as bio-templates for the development of bio-inorganic composites for many applications. In this study we used genetically modified filamentous Escherichia coli cells as template for the design of polyelectrolyte tubes that can be used as carrier for functional molecules or particles. Diversity of structures of biogenic materials has the potential to be used to construct inorganic or polymeric superior hybrid materials that reflect the form of the bio-template. Such bio-inspired materials are of great interest in diverse scientific fields like Biology, Chemistry and Material Science and can find application for the construction of functional materials or the bio-inspired synthesis of inorganic nanoparticles. Results Genetically modified filamentous E. coli cells were fixed in 2% glutaraldehyde and coated with alternating six layers of the polyanion polyelectrolyte poly(sodium-4styrenesulfonate (PSS and polycation polyelectrolyte poly(allylamine-hydrochloride (PAH. Afterwards we dissolved the E. coli cells with 1.2% sodium hypochlorite, thus obtaining hollow polyelectrolyte tubes of 0.7 μm in diameter and 5–50 μm in length. For functionalisation the polyelectrolyte tubes were coated with S-layer protein polymers followed by metallisation with Pd(0 particles. These assemblies were analysed with light microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and transmission electron microscopy. Conclusion The thus constructed new material offers possibilities for diverse applications like

  5. Resistencia a biocidas de diferentes cepas de escherichia coli

    OpenAIRE

    López Aguayo, M. Carmen; Lucas López, R.; Grande Burgos, M. José; Gálvez-del-Postigo-Ruiz, Antonio

    2010-01-01

    Los biocidas son herramientas de gran importancia para controlar la transmisión de microorganismos patógenos a través de la cadena alimentaria. En el presente estudio se ha determinado la resistencia a siete biocidas en una colección de nueve cepas de Escherichia coli, incluyendo cepas verotoxigénicas y cepas portadoras de resistencia a beta-lactámicos. Los biocidas más eficaces fueron triclosan, hexadecilpiridinio y cetrimida, seguido del cloruro de benzalconio. No se encon...

  6. Regulation of the L-arabinose operon of Escherichia coli.

    Science.gov (United States)

    Schleif, R

    2000-12-01

    Over forty years of research on the L-arabinose operon of Escherichia coli have provided insights into the mechanism of positive regulation of gene activity. This research also discovered DNA looping and the mechanism by which the regulatory protein changes its DNA-binding properties in response to the presence of arabinose. As is frequently seen in focused research on biological subjects, the initial studies were primarily genetic. Subsequently, the genetic approaches were augmented by physiological and then biochemical studies. Now biophysical studies are being conducted at the atomic level, but genetics still has a crucial role in the study of this system.

  7. Modeling the pressure inactivation dynamics of Escherichia coli

    Directory of Open Access Journals (Sweden)

    Yamamoto K.

    2005-01-01

    Full Text Available Escherichia coli, as a model microorganism, was treated in phosphate-buffered saline under high hydrostatic pressure between 100 and 300 MPa, and the inactivation dynamics was investigated from the viewpoint of predictive microbiology. Inactivation data were curve fitted by typical predictive models: logistic, Gompertz and Weibull functions. Weibull function described the inactivation curve the best. Two parameters of Weibull function were calculated for each holding pressure and their dependence on holding pressure was obtained by interpolation. With the interpolated parameters, inactivation curves were simulated and compared with the experimental data sets.

  8. Proton-linked L-fucose transport in Escherichia coli.

    OpenAIRE

    Bradley, S A; Tinsley, C R; Muiry, J A; Henderson, P J

    1987-01-01

    1. Addition of L-fucose to energy-depleted anaerobic suspensions of Escherichia coli elicited an uncoupler-sensitive alkaline pH change diagnostic of L-fucose/H+ symport activity. 2. L-Galactose or D-arabinose were also substrates, but not inducers, for the L-fucose/H+ symporter. 3. L-Fucose transport into subcellular vesicles was dependent upon respiration, displayed a pH optimum of about 5.5, and was inhibited by protonophores and ionophores. 4. These results showed that L-fucose transport ...

  9. Genome-scale genetic engineering in Escherichia coli.

    Science.gov (United States)

    Jeong, Jaehwan; Cho, Namjin; Jung, Daehee; Bang, Duhee

    2013-11-01

    Genome engineering has been developed to create useful strains for biological studies and industrial uses. However, a continuous challenge remained in the field: technical limitations in high-throughput screening and precise manipulation of strains. Today, technical improvements have made genome engineering more rapid and efficient. This review introduces recent advances in genome engineering technologies applied to Escherichia coli as well as multiplex automated genome engineering (MAGE), a recent technique proposed as a powerful toolkit due to its straightforward process, rapid experimental procedures, and highly efficient properties. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. DNA-damaging activity of patulin in Escherichia coli.

    OpenAIRE

    Lee, K S; Röschenthaler, R J

    1986-01-01

    At a concentration of 10 micrograms/ml, patulin caused single-strand DNA breaks in living cells of Escherichia coli. At 50 micrograms/ml, double-strand breaks were observed also. Single-strand breaks were repaired in the presence of 10 micrograms of patulin per ml within 90 min when the cells were incubated at 37 degrees C in M9-salts solution without a carbon source. The same concentration also induced temperature-sensitive lambda prophage and a prophage of Bacillus megaterium. When an in vi...

  11. Two classes of region III flagellar genes in Escherichia coli.

    OpenAIRE

    Kondoh, H; Ozeki, H.

    1981-01-01

    We infected various nonflagellated mutants of Escherichia coli with fla-transducing phages and followed the kinetics of the appearance of motility. Our analysis revealed two distinct classes of region III fla genes. Class II fla genes (hag, flaD) functioned 15 min later than class I fla genes (flaN, flaB, flaC, flaO, flaA, flbD, flaQ, flaP) in flagellar morphogenesis. We suggest that the two classes of fla genes are involved in two different stages, initiation (class I) and completion (class ...

  12. 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...... and functional oriC sequence. The seqA2 mutation was found to overcome the incompatibility phenotype by increasing the cellular oriC copy nnumber 3-fold thereby allowing minichromosomes to coexist with the chromosome. The replication pattern of a wild type strain with multiple integrated minichromosomes...

  13. Intestinal Colonization by Enterotoxigenic ’Escherichia Coli

    Science.gov (United States)

    1976-12-01

    here were: i. to adopt or develop an in vitro system for the study of the adhesive abilities of porcine ETEC strains which lack K88 antigen, and ii. to...Rutter. 1972. Role of the K88 antigen in the pathogenesis of neonatal diarrhea caused by Escherichia coli in piglets . Infect. Immun. 6:918-927. 10. Jones...particular regard to those produced by atypical piglet strains and by calf and lamb strains: The transmissible nature of these enterotoxins and of a K

  14. Bacterial self-defence: how Escherichia coli evades serum killing.

    Science.gov (United States)

    Miajlovic, Helen; Smith, Stephen G

    2014-05-01

    The ability to survive the bactericidal action of serum is advantageous to extraintestinal pathogenic Escherichia coli that gain access to the bloodstream. Evasion of the innate defences present in serum, including complement and antimicrobial peptides, involves multiple factors. Serum resistance mechanisms utilized by E. coli include the production of protective extracellular polysaccharide capsules and expression of factors that inhibit or interfere with the complement cascade. Recent studies have also highlighted the importance of structural integrity of the cell envelope in serum survival. These survival strategies are outlined in this review with particular attention to novel findings and recent insights into well-established resistance mechanisms. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  15. Biosynthesis and assembly of capsular polysaccharides in Escherichia coli.

    Science.gov (United States)

    Whitfield, Chris

    2006-01-01

    Capsules are protective structures on the surfaces of many bacteria. The remarkable structural diversity in capsular polysaccharides is illustrated by almost 80 capsular serotypes in Escherichia coli. Despite this variation, the range of strategies used for capsule biosynthesis and assembly is limited, and E. coli isolates provide critical prototypes for other bacterial species. Related pathways are also used for synthesis and export of other bacterial glycoconjugates and some enzymes/processes have counterparts in eukaryotes. In gram-negative bacteria, it is proposed that biosynthesis and translocation of capsular polysaccharides to the cell surface are temporally and spatially coupled by multiprotein complexes that span the cell envelope. These systems have an impact on both a general understanding of membrane trafficking in bacteria and on bacterial pathogenesis.

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    as a retrospective controlled interrupted time series (ITS) at two university teaching hospitals, intervention and control, with 736 and 552 beds, respectively. The study period was between January 2008 and September 2014. We used ITS analysis to determine significant changes in antibiotic use and resistance levels......% 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......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...

  17. 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 retrospective controlled interrupted time series (ITS) at two university teaching hospitals, intervention and control, with 736 and 552 beds, respectively. The study period was between January 2008 and September 2014. We used ITS analysis to determine significant changes in antibiotic use and resistance levels......% 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...

  18. 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...

  19. Enteropathogenic and enterohaemorrhagic Escherichia coli: more subversive elements.

    Science.gov (United States)

    Frankel, G; Phillips, A D; Rosenshine, I; Dougan, G; Kaper, J B; Knutton, S

    1998-12-01

    Enteropathogenic (EPEC) and enterohaemorrhagic Escherichia coli (EHEC) constitute a significant risk to human health worldwide. Both pathogens colonize the intestinal mucosa and, by subverting intestinal epithelial cell function, produce a characteristic histopathological feature known as the 'attaching and effacing' (A/E) lesion. Although EPEC was the first E. coli to be associated with human disease in the 1940s and 1950s, it was not until the late 1980s and early 1990s that the mechanisms and bacterial gene products used to induce this complex brush border membrane lesion and diarrhoeal disease started to be unravelled. During the past few months, there has been a burst of new data that have revolutionized some basic concepts of the molecular basis of bacterial pathogenesis in general and EPEC pathogenesis in particular. Major breakthroughs and developments in the genetic basis of A/E lesion formation, signal transduction, protein translocation, host cell receptors and intestinal colonization are highlighted in this review.

  20. Sedimentation and gravitational instability of Escherichia coli Suspension

    Science.gov (United States)

    Salin, Dominique; Douarche, Carine

    2017-11-01

    The successive runs and tumbles of Escherichia coli bacteria provide an active matter suspension of rod-like particles with a large swimming, Brownian like, diffusion. As opposed to inactive elongated particles, this diffusion prevents clustering of the particles and hence instability in the gravity field. We measure the time dependent E . coli concentration profile during their sedimentation. After some hours, due to the dioxygen consumption, a motile / non-motile front forms leading to a Rayleigh-Taylor type gravitational instability. Analysing both sedimentation and instability in the framework of active particle suspensions, we can measure the relevant bacteria hydrodynamic characteristics such as its single particle sedimentation velocity and its hindrance volume. Comparing these quantities to the ones of equivalent passive particles (ellipsoid, rod) we tentatively infer the effective shape and size of the bacteria involved in its buoyancy induced advection and diffusion. Laboratoire FAST University Paris Saclay France.

  1. Starch based polyhydroxybutyrate production in engineered Escherichia coli.

    Science.gov (United States)

    Bhatia, Shashi Kant; Shim, Young-Ha; Jeon, Jong-Min; Brigham, Christopher J; Kim, Yong-Hyun; Kim, Hyun-Joong; Seo, Hyung-Min; Lee, Ju-Hee; Kim, Jung-Ho; Yi, Da-Hye; Lee, Yoo Kyung; Yang, Yung-Hun

    2015-08-01

    Every year, the amount of chemosynthetic plastic accumulating in the environment is increasing, and significant time is required for decomposition. Bio-based, biodegradable plastic is a promising alternative, but its production is not yet a cost effective process. Decreasing the production cost of polyhydroxyalkanoate by utilizing renewable carbon sources for biosynthesis is an important aspect of commercializing this biodegradable polymer. An Escherichia coli strain that expresses a functional amylase and accumulate polyhydroxybutyrate (PHB), was constructed using different plasmids containing the amylase gene of Panibacillus sp. and PHB synthesis genes from Ralstonia eutropha. This engineered strain can utilize starch as the sole carbon source. The maximum PHB production (1.24 g/L) was obtained with 2% (w/v) starch in M9 media containing 0.15% (w/v) yeast extract and 10 mM glycine betaine. The engineered E. coli SKB99 strain can accumulate intracellular PHB up to 57.4% of cell dry mass.

  2. Comparative Genomics of Escherichia coli Strains Causing Urinary Tract Infections

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; Hancock, Viktoria; Schembri, Mark A.

    2011-01-01

    The virulence determinants of uropathogenic Escherichia coli have been studied extensively over the years, but relatively little is known about what differentiates isolates causing various types of urinary tract infections. In this study, we compared the genomic profiles of 45 strains from a range...... of different clinical backgrounds, i.e., urosepsis, pyelonephritis, cystitis, and asymptomatic bacteriuria (ABU), using comparative genomic hybridization analysis. A microarray based on 31 complete E. coli sequences was used. It emerged that there is little correlation between the genotypes of the strains...... disease categories were identified. Among these were two genomic islands, namely, pathogenicity island (PAI)-CFT073-serU and PAI-CFT073-pheU, which were significantly more associated with the pyelonephritis and urosepsis isolates than with the ABU and cystitis isolates. These two islands harbor genes...

  3. Immunogenic Domains and Secondary Structure of Escherichia coli Recombinant Secreted Protein Escherichia coli-Secreted Protein B.

    Science.gov (United States)

    Caetano, Bruna Alves; Rocha, Letícia Barboza; Carvalho, Eneas; Piazza, Roxane Maria Fontes; Luz, Daniela

    2017-01-01

    Several pathogenic bacteria are able to induce the attaching and effacing (A/E) lesion. The A/E lesion is caused by effector proteins, such as Escherichia coli-secreted protein B (EspB), responsible together with Escherichia coli-secreted protein D for forming a pore structure on the host cell, which allows the translocation of effector proteins. Different variants of this protein can be found in E. coli strains, and during natural infection or when this protein is injected, this leads to variant-specific production of antibodies, which may not be able to recognize other variants of this bacterial protein. Herein, we describe the production of a hybrid recombinant EspB toxin that comprises all known variants of this protein. This recombinant protein could be useful as an antigen for the production of antibodies with broad-range detection of EspB-bearing bacteria, or as an antigen that could be used in vaccine formulation to generate antibodies against different EspB variants, thereby increasing immunization potential. In addition, the recombinant protein allowed us to analyze its secondary structure, to propose the immunogenic regions of EspB variants, and also to characterize anti-EspB antibodies. Our results suggest that this hybrid protein or a protein composed of the conserved immunogenic regions could be used for a variety of clinical applications.

  4. Immunogenic Domains and Secondary Structure of Escherichia coli Recombinant Secreted Protein Escherichia coli-Secreted Protein B

    Science.gov (United States)

    Caetano, Bruna Alves; Rocha, Letícia Barboza; Carvalho, Eneas; Piazza, Roxane Maria Fontes; Luz, Daniela

    2017-01-01

    Several pathogenic bacteria are able to induce the attaching and effacing (A/E) lesion. The A/E lesion is caused by effector proteins, such as Escherichia coli-secreted protein B (EspB), responsible together with Escherichia coli-secreted protein D for forming a pore structure on the host cell, which allows the translocation of effector proteins. Different variants of this protein can be found in E. coli strains, and during natural infection or when this protein is injected, this leads to variant-specific production of antibodies, which may not be able to recognize other variants of this bacterial protein. Herein, we describe the production of a hybrid recombinant EspB toxin that comprises all known variants of this protein. This recombinant protein could be useful as an antigen for the production of antibodies with broad-range detection of EspB-bearing bacteria, or as an antigen that could be used in vaccine formulation to generate antibodies against different EspB variants, thereby increasing immunization potential. In addition, the recombinant protein allowed us to analyze its secondary structure, to propose the immunogenic regions of EspB variants, and also to characterize anti-EspB antibodies. Our results suggest that this hybrid protein or a protein composed of the conserved immunogenic regions could be used for a variety of clinical applications. PMID:28484467

  5. Immunogenic Domains and Secondary Structure of Escherichia coli Recombinant Secreted Protein Escherichia coli-Secreted Protein B

    Directory of Open Access Journals (Sweden)

    Roxane Maria Fontes Piazza

    2017-04-01

    Full Text Available Several pathogenic bacteria are able to induce the attaching and effacing (A/E lesion. The A/E lesion is caused by effector proteins, such as Escherichia coli-secreted protein B (EspB, responsible together with Escherichia coli-secreted protein D for forming a pore structure on the host cell, which allows the translocation of effector proteins. Different variants of this protein can be found in E. coli strains, and during natural infection or when this protein is injected, this leads to variant-specific production of antibodies, which may not be able to recognize other variants of this bacterial protein. Herein, we describe the production of a hybrid recombinant EspB toxin that comprises all known variants of this protein. This recombinant protein could be useful as an antigen for the production of antibodies with broad-range detection of EspB-bearing bacteria, or as an antigen that could be used in vaccine formulation to generate antibodies against different EspB variants, thereby increasing immunization potential. In addition, the recombinant protein allowed us to analyze its secondary structure, to propose the immunogenic regions of EspB variants, and also to characterize anti-EspB antibodies. Our results suggest that this hybrid protein or a protein composed of the conserved immunogenic regions could be used for a variety of clinical applications.

  6. Atividades citotóxica e hemolítica em Escherichia coli uropatogênicas Citotoxic and hemolytic activities of uropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    João Ramos Costa Andrade

    1988-06-01

    Full Text Available Estudamos 59 Escherichia coli uropatogênicas (ECUP obtidas de pacientes com infecção urinária e 30 E. coli originárias das fezes de indivíduos normais. Cada amostra originou-se de um paciente ou controle. Verificamos que 44% e 3,3% respectivamente eram hemolíticas em meio sólido segundo a origem. Apenas 15% das ECUP hemolíticas produziram alfa-hemolisina, isoladamente ou em associação com ß-hemolisina. A alfa-hemolisina correspondeu a 92% das amostras com atividade hemolítica. Não encontramos correlação entre títulos de alfa-hemolisina e o sítio de origem das ECUP (infecção alta ou baixa. Em 71% das ECUP e 30% das E. coli fecais detectamos a produção de citotoxina com ação citocida para linhagens celulares epitelióides como Vero, He-La e Hep-2 e pouco ativa para fibroblastos de embrião de galinha. A produção desta citotoxina não apresenta correlação com a síntese de hemolisinas. Não verificamos associação entre títulos citotóxicos e origem das ECUP. Certas características biológicas desta citotoxina como a resposta morfológica que determina nas células, o aumento dos títulos citotóxicos com o tempo, sua atividade citocida irreversível e sua termolabilidade sugerem analogia com a Verotoxina (VT de E. coli. As células afetadas pela citoxina inicialmente mostram aspecto estrelado, tornam-se arredondadas e finalmente desprendem-se do seu suporte. É sugerido que a produção de citotoxina por E. coli aderidas às mucosas do trato urinário possa contribuir para a agressão ao uroepitélio.Fifty nine Escherichia coli strains obtained from patients with upper or lower urinary tract infections (UTI and 30 E. coli strains isolated from stools of healthy individuals were tested for hemolytic and totoxic activities. Forty four percent of uropathologenic e. coli (UPEC and 3.3% of fecal E. coli were hemolytic. Among the hemolytic UPEC, 92% produced x-hemolysin. A cytotoxic activity was detected in culture

  7. How Escherichia coli Circumvent Complement-Mediated Killing

    Directory of Open Access Journals (Sweden)

    Angela S. Barbosa

    2017-04-01

    Full Text Available Complement is a crucial arm of the innate immune response against invading bacterial pathogens, and one of its main functions is to recognize and destroy target cells. Similar to other pathogens, Escherichia coli has evolved mechanisms to overcome complement activation. It is well known that capsular polysaccharide may confer resistance to complement-mediated killing and phagocytosis, being one of the strategies adopted by this bacterium to survive in serum. In addition, proteases produced by E. coli have been shown to downregulate the complement system. Pic, an autotransporter secreted by different pathogens in the Enterobacteriaceae family, is able to cleave C2, C3/C3b, and C4/C4b and works synergistically with human Factor I and Factor H (FH, thereby promoting inactivation of C3b. Extracellular serine protease P, a serine protease of enterohemorrhagic E. coli (EHEC, downregulates complement activation by cleaving C3/C3b and C5. StcE, a metalloprotease secreted by EHEC, inhibits the classical complement-mediated cell lysis by potentiating the action of C1 inhibitor, and the periplasmic protease Prc contributes to E. coli complement evasion by interfering with the classical pathway activation and by preventing membrane attack complex deposition. Finally, it has been described that E. coli proteins interact with negative complement regulators to modulate complement activation. The functional consequences resulting from the interaction of outer membrane protein A, new lipoprotein I, outer membrane protein W, and Stx2 with proteins of the FH family and C4b-binding protein (C4BP are discussed in detail. In brief, in this review, we focused on the different mechanisms used by pathogenic E. coli to circumvent complement attack, allowing these bacteria to promote a successful infection.

  8. Pathogenic Escherichia coli in rural household container waters.

    Science.gov (United States)

    Jagals, P; Barnard, T G; Mokoena, M M; Ashbolt, N; Roser, D J

    2013-01-01

    Plastic containers in the range of 5-20 L are widely used - especially in rural African settings - to collect, transport and store water for domestic use, including drinking, bathing and hygiene. The pathogen content of the waters in these containers has not been adequately characterized as yet. This paper presents the primary findings of a synoptic survey of drinking water quality samples from these containers and involved collection of bacterial indicator and pathogenicity gene data. In total, 571 samples of a variety of waters were taken in rural communities in South Africa and the Escherichia coli numbers measured. Of the E. coli positive samples, 46% (n = 148) were screened for the presence of E. coli pathogen gene markers. Though synoptic, the survey provided many insights into the issues that drove the study. Container use markedly degraded water quality as judged by indicator counts, even where improved water supply services were in place. Household container use also appeared to promote regrowth or contamination of containers with pathogenic E. coli strains. Polymerase chain reaction (PCR) analysis also showed that the diversity of potential pathogenic E. coli carrying virulence genes was great. All seven genes screened for (Ial, Stx1, Stx2, EaeA, Eagg, ST, LT) were found in the waters, alone or as mixtures (number of different combinations = 31) including those characteristic of the more dangerous invasive and haemorrhagic E. coli strains. Given the central role of containers in the management of water supply to rural communities, it is clear the microbiology of these waters requires much further characterization.

  9. 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.

  10. 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.

  11. Accumulation and efflux of polychlorinated biphenyls in Escherichia coli.

    Science.gov (United States)

    Geng, Shen; Fang, Jun; Turner, Kendrick B; Daunert, Sylvia; Wei, Yinan

    2012-06-01

    Polychlorinated biphenyls (PCBs) are environmental pollutants that have been associated with numerous adverse health effects in human and animals. Hydroxylated PCBs (HPCBs) are the product of the oxidative metabolism of PCBs. The presence of hydroxyl groups in HPCBs makes these compounds more hydrophilic than the parent PCBs. One of the best approaches to break down and remove these contaminants is bioremediation; an environmentally friendly process that uses microorganisms to degrade hazardous chemicals into non-toxic ones. In this study, we investigated the cellular accumulation and toxicity of selected PCBs and HPCBs in Gram-negative bacteria, using Escherichia coli as a model organism. We found that none of the five PCBs tested were toxic to E. coli, presumably due to their limited bioavailability. Nevertheless, different HPCBs tested showed different levels of toxicity. Furthermore, we demonstrated that the primary multidrug efflux system in E. coli, AcrAB-TolC, facilitated the efflux of HPCBs out of the cell. Since AcrAB-TolC is constitutively expressed in E. coli and is conserved in all sequenced Gram-negative bacterial genomes, our results suggest that the efflux activities of multidrug resistant pumps may affect the accumulation and degradation of PCBs in Gram-negative bacteria.

  12. 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.

  13. Copper import in Escherichia coli by the yersiniabactin metallophore system.

    Science.gov (United States)

    Koh, Eun-Ik; Robinson, Anne E; Bandara, Nilantha; Rogers, Buck E; Henderson, Jeffrey P

    2017-09-01

    Copper plays a dual role as a nutrient and a toxin during bacterial infections. While uropathogenic Escherichia coli (UPEC) strains can use the copper-binding metallophore yersiniabactin (Ybt) to resist copper toxicity, Ybt also converts bioavailable copper to Cu(II)-Ybt in low-copper conditions. Although E. coli have long been considered to lack a copper import pathway, we observed Ybt-mediated copper import in UPEC using canonical Fe(III)-Ybt transport proteins. UPEC removed copper from Cu(II)-Ybt with subsequent re-export of metal-free Ybt to the extracellular space. Copper released through this process became available to an E. coli cuproenzyme (the amine oxidase TynA), linking this import pathway to a nutrient acquisition function. Ybt-expressing E. coli thus engage in nutritional passivation, a strategy of minimizing a metal ion's toxicity while preserving its nutritional availability. Copper acquisition through this process may contribute to the marked virulence defect of Ybt-transport-deficient UPEC.

  14. Curli fimbria: an Escherichia coli adhesin associated with human cystitis.

    Science.gov (United States)

    Cordeiro, Melina Aparecida; Werle, Catierine Hirsch; Milanez, Guilherme Paier; Yano, Tomomasa

    2016-01-01

    Escherichia coli is the major causative agent of human cystitis. In this study, a preliminary molecular analysis carried out by PCR (polymerase chain reaction) demonstrated that 100% of 31 E. coli strains isolated from patients with recurrent UTIs (urinary tract infections) showed the presence of the curli fimbria gene (csgA). Curli fimbria is known to be associated with bacterial biofilm formation but not with the adhesion of human cystitis-associated E. coli. Therefore, this work aimed to study how curli fimbria is associated with uropathogenic E. coli (UPEC) as an adhesion factor. For this purpose, the csgA gene was deleted from strain UPEC-4, which carries three adhesion factor genes (csgA, fimH and ompA). The wild-type UPEC-4 strain and its mutant (ΔcsgA) were analyzed for their adhesion ability over HTB-9 (human bladder carcinoma), Vero (kidney cells of African green monkey) and HUVEC (human umbilical vein) cells in the presence of α-d-mannose. All the wild-type UPEC strains tested (100%) were able to adhere to all three cell types, while the UPEC-4 ΔcsgA mutant lost its adherence to HTB-9 but continued to adhere to the HUVEC and Vero cells. The results suggest that curli fimbria has an important role in the adhesion processes associated with human UPEC-induced cystitis. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  15. Adsorption kinetics of Escherichia Coli on different Carbon Nanoforms

    Directory of Open Access Journals (Sweden)

    Md. Shamimul Haque Choudhury

    2012-03-01

    Full Text Available Adsorption of Escherichia coli (E. Coli bacterial cells on different carbon nanoforms (i.e. Single walled carbon nanotube (SWCNT, Multiwalled Carbon nanotube (MWCNT, graphite and mixedFullerene aggregates is studied. The diffusivities of pure cultures of E. Coli cells in SWCNT aggregates, MWCN aggregates, Graphite aggregates and Mixed Fullerenes was observed to be 1.5×10-9 cm2/s, 0.55×10-9 cm2/s, 0.8×10-9 cm2/s, and 1.016×10-9 cm2/s, respectively. In addition to batch adsorption studies, optical microscopy studies were also performed. The results suggest that diffusion kinetics ofbacterial cells depends on the concentration and average diameter of the nano-carbon aggregates and also on the type of material used. Diffusivity of E. Coli. in SWCNT was observed to be highest and isabout three times greater than for MWCNT, about two times greater than for graphite and about 1.5 times greater than for Fullerene aggregates. SWCNT seems to be best candidates (amongst the othermaterials studied for adsorption of microorganisms – paying their way for application towards microorganisms filters and for biosensors (where it is desired to simultaneously detect and capture bio-threat agents.

  16. Magnetically-Actuated Escherichia coli System for Micro Lithography

    Science.gov (United States)

    Lauback, S.; Brown, E.; Pérez-Guzman, L.; Peace, C.; Pierce, C.; Lower, B. H.; Lower, S. K.; Sooryakumar, R.

    2015-03-01

    Technologies that control matter at the nano- and micro-scale are crucial for developing new engineered materials and devices. While the more traditional approaches for such manipulations often depend on lithographic fabrication, they can be expanded upon by taking advantage of the biological systems within a living cell which also operate on the nano- and micro- scale. In this study, a system is being developed to functionalize a targeted location on the surface of a chip with the protein AmCyan from transformed Escherichia coli cells. Using established methods in molecular biology where a plasmid with the amcyan gene sequence is inserted into the cell, E. coli are engineered to express the AmCyan protein on their outer surface. In order to transport the cells to the targeted location, the transformed E. coli are labeled with superparamagnetic micro-beads which exert directed forces on the cells in an external field. Preliminary results of the protein expression on E. coli, the transport of the cell through weak magnetic fields to targeted locations and the potential to transfer protein from the cell to the chip surface will be presented.

  17. Accuracy of Genome Reassembly in γ-Irradiated Escherichia coli

    Directory of Open Access Journals (Sweden)

    Jelena Repar

    2013-01-01

    Full Text Available γ-Radiation, a powerful DNA-damaging agent, can often lead to the formation of genome rearrangements. In this study, we have assessed the capacity of Escherichia coli to accurately reassemble its genome after multiple double-strand DNA breaks caused by γ-radiation. It has recently been shown that very high doses of γ-radiation or RecA protein deficiency cause erroneous chromosomal assemblies in Deinococcus radiodurans, a highly radiation-resistant bacterium. Accordingly, we have examined the accuracy of genome reassembly in both wild-type and recA strains of E. coli after exposure to the doses of γ-radiation which reduce the survival by 10^6 - to 10^7 -fold. Thirty-eight percent of wild-type survivors showed gross genome changes, most of which were found to be the consequence of the excision of e14, a 15-kb defective prophage. Only one additional type of gross genome rearrangement was detected, presumably representing the duplication of a DNA fragment. These results demonstrate an unexpectedly accurate genome reassembly in wild-type E. coli. We have detected no genome rearrangements in recA recBCD and recA recBCD sbcB mutants, suggesting that RecA-independent DNA repair in E. coli may also be accurate.

  18. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Strain-dependent carotenoid productions in metabolically engineered Escherichia coli.

    Science.gov (United States)

    Chae, Han Seung; Kim, Kong-Hwan; Kim, Sun Chang; Lee, Pyung Cheon

    2010-12-01

    Seven Escherichia coli strains, which were metabolically engineered with carotenoid biosynthetic pathways, were systematically compared in order to investigate the strain-specific formation of carotenoids of structural diversity. C30 acyclic carotenoids, diaponeurosporene and diapolycopene were well produced in all E. coli strains tested. However, the C30 monocyclic diapotorulene formation was strongly strain dependent. Reduced diapotorulene formation was observed in the E. coli strain Top10, MG1655, and MDS42 while better formation was observed in the E. coli strain JM109, SURE, DH5a, and XL1-Blue. Interestingly, C40 carotenoids, which have longer backbones than C30 carotenoids, also showed strain dependency as C30 diapotorulene did. Quantitative analysis showed that the SURE strain was the best producer for C40 acyclic lycopene, C40 dicyclic β-carotene, and C30 monocyclic diapotorulene. Of the seven strains examined, the highest volumetric productivity for most of the carotenoids structures was observed in the recombinant SURE strain. In conclusion, we showed that recombinant hosts and carotenoid structures influenced carotenoid productions significantly, and this information can serve as the basis for the subsequent development of microorganisms for carotenoids of interest.

  20. Prevalence and Antibiogram Profiling of Escherichia coli Pathotypes Isolated from the Kat River and the Fort Beaufort Abstraction Water

    Directory of Open Access Journals (Sweden)

    Nolonwabo Nontongana

    2014-08-01

    Full Text Available Escherichia coli is a widespread bacterium encompassing a variety of strains, ranging from highly pathogenic strains, causing worldwide outbreaks of severe diseases to avirulent, well characterized safe laboratory strains. This study evaluated the prevalence and antibiogram profiles of E. coli pathotypes isolated from the Kat River and Fort Beaufort abstraction water. A total of 171 out of 278 confirmed E. coli isolates were positive for at least one pathogenic determinant and these included enteropathogenic E. coli (6%, enterotoxigenic E. coli (47%, uropathogenic E. coli (2%, neonatal meningitis E. coli (5%, diffusely adherent E. coli (1% and enterohaemorrhagic E. coli (1%. Interestingly, enteroinvasive and enteroaggregative E. coli were not detected. The phenotypic antibiogram profiles of the isolates revealed that all were resistant to penicillin G, while 98% and 38% of the pathotypes were resistant to ampicillin and trimethoprim-sulphamethoxazole, respectively. About 8% of the isolates were resistant to streptomycin. More than half of the isolates exhibited multiple antibiotic resistance with 44% being resistant to three antibiotics and 8% resistant to four antibiotics. We conclude that the Kat River is a reservoir of potentially virulent antibiotic resistant E. coli strains that can cause serious health risks to humans who drink raw water from this river, or in the case that consumption of treated drinking water coincides with failed drinking water processes.

  1. Occurrence of Escherichia coli O157 in a river used for fresh ...

    African Journals Online (AJOL)

    PRECIOUS

    2010-01-11

    Jan 11, 2010 ... Key words: Escherichia coli O157, contamination, irrigation water, nitrate, fresh produce, surface waters. INTRODUCTION. Escherichia coli O157 is an important agent of food- and water-borne illnesses in humans globally (Chalmers et al., 2000; Bettelheim and Beutin, 2003; Duffy, 2003). The first reported ...

  2. 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.

  3. A Novel 7-Single Nucleotide Polymorphism-Based Clonotyping Test Allows Rapid Prediction of Antimicrobial Susceptibility of Extraintestinal Escherichia coli Directly From Urine Specimens

    OpenAIRE

    Tchesnokova, Veronika; Avagyan, Hovhannes; Billig, Mariya; Chattopadhyay, Sujay; Aprikian, Pavel; Chan, Diana; Pseunova, Julietta; Rechkina, Elena; Riddell, Kim; Scholes, Delia; Fang, Ferric C.; Johnson, James R.; Sokurenko, Evgeni V.

    2016-01-01

    Background. ?Escherichia coli is a highly clonal pathogen. Extraintestinal isolates belong to a limited number of genetically related groups, which often exhibit characteristic antimicrobial resistance profiles. Methods. ?We developed a rapid clonotyping method for extraintestinal E coli based on detection of the presence or absence of 7 single nucleotide polymorphisms (SNPs) within 2 genes (fumC and fimH). A reference set of 2559 E coli isolates, primarily of urinary origin, was used to pred...

  4. 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 chro......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 chromosomes contain multiple replication forks and must be segregated while this complex pattern of replication is still ongoing. Here, we show that replication and segregation continue in step, starting at the origin and progressing to the replication terminus. Thus, early-replicated markers on the multiple......-branched chromosomes continue to separate soon after replication to form separate protonucleoids, even though they are not segregated into different daughter cells until later generations. The segregation pattern follows the pattern of chromosome replication and does not follow the cell division cycle. No extensive...

  5. DNA-damaging activity of patulin in Escherichia coli.

    Science.gov (United States)

    Lee, K S; Röschenthaler, R J

    1986-01-01

    At a concentration of 10 micrograms/ml, patulin caused single-strand DNA breaks in living cells of Escherichia coli. At 50 micrograms/ml, double-strand breaks were observed also. Single-strand breaks were repaired in the presence of 10 micrograms of patulin per ml within 90 min when the cells were incubated at 37 degrees C in M9-salts solution without a carbon source. The same concentration also induced temperature-sensitive lambda prophage and a prophage of Bacillus megaterium. When an in vitro system with permeabilized Escherichia coli cells was used, patulin at 10 micrograms/ml induced DNA repair synthesis and inhibited DNA replication. The in vivo occurrence of DNA strand breaks and DNA repair correlated with the in vitro induction of repair synthesis. In vitro the RNA synthesis was less affected, and overall protein synthesis was not inhibited at 10 micrograms/ml. Only at higher concentrations (250 to 500 micrograms/ml) was inhibition of in vitro protein synthesis observed. Thus, patulin must be regarded as a mycotoxin with selective DNA-damaging activity. PMID:2431653

  6. Atypical Enteropathogenic Escherichia coli Secretes Plasmid Encoded Toxin

    Directory of Open Access Journals (Sweden)

    Rita C. Ruiz

    2014-01-01

    Full Text Available Plasmid encoded toxin (Pet is a serine protease originally described in enteroaggregative Escherichia coli (EAEC prototype strain 042 whose entire characterization was essentially obtained from studies performed with the purified toxin. Here we show that Pet is not exclusive to EAEC. Atypical enteropathogenic Escherichia coli (aEPEC strains, isolated from diarrhea cases, express Pet and its detection in supernatants of infected HEp-2 cells coincides with the appearance of cell damage, which, in turn, were similar to those described with purified Pet. Pet secretion and the cytotoxic effects are time and culture medium dependent. In presence of DMEM supplemented with tryptone cell rounding and detachment were observed after just 5 h of incubation with the bacteria. In the absence of tryptone, the cytotoxic effects were detected only after 24 h of infection. We also show that, in addition to the prototype EAEC, other pet+ EAEC strains, also isolated from diarrhea cases, induce cellular damage in the same degree as the aEPEC. The cytotoxic effects of EAEC and aEPEC strains were significantly reduced in the presence of a serine protease inhibitor or anti-Pet IgG serum. Our results show a common aspect between the aEPEC and EAEC and provide the first evidence pointing to a role of Pet in aEPEC pathogenesis.

  7. Presence and antimicrobial susceptibility of Escherichia coli recovered from retail chicken in China.

    Science.gov (United States)

    Wu, Qian; Xi, Meili; Lv, Xiaoying; Xu, Yunfeng; Feng, Yuqing; Li, Qiong; Yang, Qinnan; Xia, Xiaodong

    2014-10-01

    The aim of this study was to determine the prevalence and antimicrobial susceptibility of Escherichia coli in retail whole chicken in the People 9 s Republic of China. Five hundred seventy-six raw whole chicken samples, randomly purchased from 146 farmers' markets or supermarkets in four provinces from March through December 2010, were analyzed for E. coli contamination, and the E. coli isolates were further tested for the presence of virulence genes and antimicrobial susceptibility. The overall positive rate for E. coli in retail chicken was 69.1%. E. coli prevalence was the highest in Beijing (86.8%), followed by Henan province (78.5%), Shaanxi province (65.3%), and the lowest prevalence was found in Sichuan province (45.8%). Among 398 isolates recovered, only the eae gene was detected in one isolate; no other virulence genes were detected. Resistance was most common to tetracycline (84.4%), followed by nalidixic acid (74.1%), ampicillin (71.1%), trimethoprim-sulfamethoxazole (70.1%), amoxicillin-clavulanic acid (68.8%), and streptomycin (58.5%). Lower resistance was detected to chloramphenicol (43.7%), kanamycin (42.7%), ciprofloxacin (30.2%), gentamicin (29.4%), cefoperazone (13.6%), amikacin (12.6%), gatifloxacin (8%), and cefoxitin (7.8%). Only 3.8% of the isolates were susceptible to all tested antimicrobials. Six percent of the isolates displayed resistance to one antimicrobial, 6.3% to two, and 83.9% to three or more of the antimicrobials. Our findings indicate that retail chicken in China was commonly contaminated with E. coli, and many E. coli strains exhibited multiple drug resistance. The implementation of good manufacturing practices throughout the poultry production chain is necessary to reduce E. coli contamination in retail chicken, and the prudent use of antibiotics is imperative in poultry production in China.

  8. Instability of repeated DNAs during transformation in Escherichia coli.

    Science.gov (United States)

    Hashem, Vera I; Klysik, Elzbieta A; Rosche, William A; Sinden, Richard R

    2002-05-22

    Escherichia coli has provided an important model system for understanding the molecular basis for genetic instabilities associated with repeated DNA. Changes in triplet repeat length during growth following transformation in E. coli have been used as a measure of repeat instability. However, very little is known about the molecular and biological changes that may occur on transformation. Since only a small proportion of viable cells become competent, uncertainty exists regarding the nature of these transformed cells. To establish whether the process of transformation can be inherently mutagenic for certain DNA sequences, we used a genetic assay in E. coli to compare the frequency of genetic instabilities associated with transformation with those occurring in plasmid maintained in E. coli. Our results indicate that, for certain DNA sequences, bacterial transformation can be highly mutagenic. The deletion frequency of a 106 bp perfect inverted repeat is increased by as much as a factor of 2 x 10(5) following transformation. The high frequency of instability was not observed when cells stably harboring plasmid were rendered competent. Thus, the process of transformation was required to observe the instability. Instabilities of (CAG).(CTG) repeats are also dramatically elevated upon transformation. The magnitude of the instability is dependent on the nature and length of the repeat. Differences in the methylation status of plasmid used for transformation and the methylation and restriction/modification systems present in the bacterial strain used must also be considered in repeat instability measurements. Moreover, different E. coli genetic backgrounds show different levels of instability during transformation.

  9. Brote causado por Escherichia coli en Chalco, México

    Directory of Open Access Journals (Sweden)

    Cortés-Ortiz Iliana Alejandra

    2002-01-01

    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.

  10. Genomic and Phenomic Study of Mammary Pathogenic Escherichia coli

    Science.gov (United States)

    Blum, Shlomo E.; Heller, Elimelech D.; Sela, Shlomo; Elad, Daniel; Edery, Nir; Leitner, Gabriel

    2015-01-01

    Escherichia coli is a major etiological agent of intra-mammary infections (IMI) in cows, leading to acute mastitis and causing great economic losses in dairy production worldwide. Particular strains cause persistent IMI, leading to recurrent mastitis. Virulence factors of mammary pathogenic E. coli (MPEC) involved pathogenesis of mastitis as well as those differentiating strains causing acute or persistent mastitis are largely unknown. This study aimed to identify virulence markers in MPEC through whole genome and phenome comparative analysis. MPEC strains causing acute (VL2874 and P4) or persistent (VL2732) mastitis were compared to an environmental strain (K71) and to the genomes of strains representing different E. coli pathotypes. Intra-mammary challenge in mice confirmed experimentally that the strains studied here have different pathogenic potential, and that the environmental strain K71 is non-pathogenic in the mammary gland. Analysis of whole genome sequences and predicted proteomes revealed high similarity among MPEC, whereas MPEC significantly differed from the non-mammary pathogenic strain K71, and from E. coli genomes from other pathotypes. Functional features identified in MPEC genomes and lacking in the non-mammary pathogenic strain were associated with synthesis of lipopolysaccharide and other membrane antigens, ferric-dicitrate iron acquisition and sugars metabolism. Features associated with cytotoxicity or intra-cellular survival were found specifically in the genomes of strains from severe and acute (VL2874) or persistent (VL2732) mastitis, respectively. MPEC genomes were relatively similar to strain K-12, which was subsequently shown here to be possibly pathogenic in the mammary gland. Phenome analysis showed that the persistent MPEC was the most versatile in terms of nutrients metabolized and acute MPEC the least. Among phenotypes unique to MPEC compared to the non-mammary pathogenic strain were uric acid and D-serine metabolism. This study

  11. A Novel Putrescine Exporter SapBCDF of Escherichia coli*

    Science.gov (United States)

    Sugiyama, Yuta; Nakamura, Atsuo; Matsumoto, Mitsuharu; Kanbe, Ayaka; Sakanaka, Mikiyasu; Higashi, Kyohei; Igarashi, Kazuei; Katayama, Takane; Suzuki, Hideyuki; Kurihara, Shin

    2016-01-01

    Recent research has suggested that polyamines (putrescine, spermidine, and spermine) in the intestinal tract impact the health of animals either negatively or positively. The concentration of polyamines in the intestinal tract results from the balance of uptake and export of the intestinal bacteria. However, the mechanism of polyamine export from bacterial cells to the intestinal lumen is still unclear. In Escherichia coli, PotE was previously identified as a transporter responsible for putrescine excretion in an acidic growth environment. We observed putrescine concentration in the culture supernatant was increased from 0 to 50 μm during growth of E. coli under neutral conditions. Screening for the unidentified putrescine exporter was performed using a gene knock-out collection of E. coli, and deletion of sapBCDF significantly decreased putrescine levels in the culture supernatant. Complementation of the deletion mutant with the sapBCDF genes restored putrescine levels in the culture supernatant. Additionally, the ΔsapBCDF strain did not facilitate uptake of putrescine from the culture supernatant. Quantification of stable isotope-labeled putrescine derived from stable isotope-labeled arginine supplemented in the medium revealed that SapBCDF exported putrescine from E. coli cells to the culture supernatant. It was previously reported that SapABCDF of Salmonella enterica sv. typhimurium and Haemophilus influenzae conferred resistance toantimicrobial peptides; however, the E. coli ΔsapBCDF strain did not affect resistance to antimicrobial peptide LL-37. These results strongly suggest that the natural function of the SapBCDF proteins is the export of putrescine. PMID:27803167

  12. A Novel Putrescine Exporter SapBCDF of Escherichia coli.

    Science.gov (United States)

    Sugiyama, Yuta; Nakamura, Atsuo; Matsumoto, Mitsuharu; Kanbe, Ayaka; Sakanaka, Mikiyasu; Higashi, Kyohei; Igarashi, Kazuei; Katayama, Takane; Suzuki, Hideyuki; Kurihara, Shin

    2016-12-16

    Recent research has suggested that polyamines (putrescine, spermidine, and spermine) in the intestinal tract impact the health of animals either negatively or positively. The concentration of polyamines in the intestinal tract results from the balance of uptake and export of the intestinal bacteria. However, the mechanism of polyamine export from bacterial cells to the intestinal lumen is still unclear. In Escherichia coli, PotE was previously identified as a transporter responsible for putrescine excretion in an acidic growth environment. We observed putrescine concentration in the culture supernatant was increased from 0 to 50 μm during growth of E. coli under neutral conditions. Screening for the unidentified putrescine exporter was performed using a gene knock-out collection of E. coli, and deletion of sapBCDF significantly decreased putrescine levels in the culture supernatant. Complementation of the deletion mutant with the sapBCDF genes restored putrescine levels in the culture supernatant. Additionally, the ΔsapBCDF strain did not facilitate uptake of putrescine from the culture supernatant. Quantification of stable isotope-labeled putrescine derived from stable isotope-labeled arginine supplemented in the medium revealed that SapBCDF exported putrescine from E. coli cells to the culture supernatant. It was previously reported that SapABCDF of Salmonella enterica sv. typhimurium and Haemophilus influenzae conferred resistance toantimicrobial peptides; however, the E. coli ΔsapBCDF strain did not affect resistance to antimicrobial peptide LL-37. These results strongly suggest that the natural function of the SapBCDF proteins is the export of putrescine. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. 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

  14. Codon optimisation is key for pernisine expression in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Marko Šnajder

    Full Text Available Pernisine is an extracellular serine protease from the hyperthermophilic Archaeon Aeropyrum pernix K1. Low yields from the natural host and expression problems in heterologous hosts have limited the potential applications of pernisine in industry.The challenges of pernisine overexpression in Escherichia coli were overcome by codon preference optimisation and de-novo DNA synthesis. The following forms of the pernisine gene were cloned into the pMCSGx series of vectors and expressed in E. coli cells: wild-type (pernisinewt, codon-optimised (pernisineco, and codon-optimised with a S355A mutation of a predicted active site (pernisineS355Aco. The fusion-tagged pernisines were purified using fast protein liquid chromatography equipped with Ni2+ chelate and gel filtration chromatography columns. The identities of the resultant proteins were confirmed with N-terminal sequencing, tandem mass spectrometry analysis, and immunodetection. Pernisinewt was not expressed in E. coli at detectable levels, while pernisineco and pernisineS355Aco were expressed and purified as 55-kDa proforms with yields of around 10 mg per litre E. coli culture. After heat activation of purified pernisine, the proteolytic activity of the mature pernisineco was confirmed using zymography, at a molecular weight of 36 kDa, while the mutant pernisineS355Aco remained inactive. Enzymatic performances of pernisine evaluated under different temperatures and pHs demonstrate that the optimal enzymatic activity of the recombinant pernisine is ca. 100°C and pH 7.0, respectively.These data demonstrate that codon optimisation is crucial for pernisine overexpression in E. coli, and that the proposed catalytic Ser355 has an important role in pernisine activity, but not in its activation process. Pernisine is activated by autoproteolytical cleavage of its N-terminal proregion. We have also confirmed that the recombinant pernisine retains the characteristics of native pernisine, as a calcium

  15. Discovery of Escherichia coli CRISPR sequences in an undergraduate laboratory.

    Science.gov (United States)

    Militello, Kevin T; Lazatin, Justine C

    2017-05-01

    Clustered regularly interspaced short palindromic repeats (CRISPRs) represent a novel type of adaptive immune system found in eubacteria and archaebacteria. CRISPRs have recently generated a lot of attention due to their unique ability to catalog foreign nucleic acids, their ability to destroy foreign nucleic acids in a mechanism that shares some similarity to RNA interference, and the ability to utilize reconstituted CRISPR systems for genome editing in numerous organisms. In order to introduce CRISPR biology into an undergraduate upper-level laboratory, a five-week set of exercises was designed to allow students to examine the CRISPR status of uncharacterized Escherichia coli strains and to allow the discovery of new repeats and spacers. Students started the project by isolating genomic DNA from E. coli and amplifying the iap CRISPR locus using the polymerase chain reaction (PCR). The PCR products were analyzed by Sanger DNA sequencing, and the sequences were examined for the presence of CRISPR repeat sequences. The regions between the repeats, the spacers, were extracted and analyzed with BLASTN searches. Overall, CRISPR loci were sequenced from several previously uncharacterized E. coli strains and one E. coli K-12 strain. Sanger DNA sequencing resulted in the discovery of 36 spacer sequences and their corresponding surrounding repeat sequences. Five of the spacers were homologous to foreign (non-E. coli) DNA. Assessment of the laboratory indicates that improvements were made in the ability of students to answer questions relating to the structure and function of CRISPRs. Future directions of the laboratory are presented and discussed. © 2016 by The International Union of Biochemistry and Molecular Biology, 45(3):262-269, 2017. © 2016 The International Union of Biochemistry and Molecular Biology.

  16. Prevalence and behavior of multidrug-resistant shiga toxin-producing Escherichia coli, enteropathogenic E. coli and enterotoxigenic E. coli on coriander.

    Science.gov (United States)

    Gómez-Aldapa, Carlos A; Segovia-Cruz, Jesús A; Cerna-Cortes, Jorge F; Rangel-Vargas, Esmeralda; Salas-Rangel, Laura P; Gutiérrez-Alcántara, Eduardo J; Castro-Rosas, Javier

    2016-10-01

    The prevalence and behavior of multidrug-resistant diarrheagenic Escherichia coli pathotypes on coriander was determined. One hundred coriander samples were collected from markets. Generic E. coli were determined using the most probable number procedure. Diarrheagenic E. coli pathotypes (DEPs) were identified using two multiplex polymerase chain reaction procedures. Susceptibility to sixteen antibiotics was tested for the isolated DEPs strains by standard test. The behavior of multidrug-resistant DEPs isolated from coriander was determined on coriander leaves and chopped coriander at 25°± 2 °C and 3°± 2 °C. Generic E. coli and DEPs were identified, respectively, in 43 and 7% of samples. Nine DEPs strains were isolated from positive coriander samples. The identified DEPs included Shiga toxin-producing E. coli (STEC, 4%) enterotoxigenic E. coli (ETEC, 2%) and enteropathogenic E. coli (EPEC, 1%). All isolated DEPs strains exhibited multi-resistance to antibiotics. On inoculated coriander leaves stored at 25°± 2 °C or 3°± 2 °C, no growth was observed for multidrug-resistant DEPs strains. However, multidrug-resistant DEPs strains grew in chopped coriander: after 24 h at 25° ± 2 °C, DEPs strains had grown to approximately 3 log CFU/g. However, at 3°± 2 °C the bacterial growth was inhibited. To the best of our knowledge, this is the first report of the presence and behavior of multidrug-resistant STEC, ETEC and EPEC on coriander and chopped coriander. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Multi-drug-resistant enterotoxigenic and enterohemorrhagic Escherichia coli isolated from children with diarrhea.

    Science.gov (United States)

    Zeighami, Habib; Haghi, Fakhri; Hajiahmadi, Fahimeh; Kashefiyeh, Mehdi; Memariani, Mojtaba

    2015-06-01

    Multi-drug-resistant (MDR) diarrheagenic Escherichia coli (DEC) has rapidly spread worldwide and represents the most serious threat to the management of diarrhea in developing countries. During the period from March 2011 to January 2012, a total of 450 stool samples of diarrheal children aged 0-60 months were studied. In order to detect enterotoxigenic E. coli (ETEC) and enterohemorrhagic E. coli (EHEC) simultaneously, a mixture of four primer pairs specific for eltB, estA, vt1, and vt2 genes was used in a multiplex PCR. Antimicrobial susceptibility testing was performed as the Clinical and Laboratory Standards Institute (CLSI) guidelines. A total of 140 (31·1%) DEC were isolated from 450 stool samples. Diarrheagenic E. coli exhibited high-level resistance to aztreonam (80·7%), amoxicillin (74·4%), and tetracycline (69·3%). Also, 86·4% of E. coli isolates were resistant to at least three different classes of antimicrobial agents and considered as MDR. The frequency of ETEC and EHEC pathotypes was 46·4 and 12·1%, respectively and all of these isolates were MDR. In conclusion, MDR ETEC continues to be an important agent associated with diarrhea in children from Tabriz, Iran.

  18. Engineering the biological conversion of methanol to specialty chemicals in Escherichia coli.

    Science.gov (United States)

    Whitaker, W Brian; Jones, J Andrew; Bennett, R Kyle; Gonzalez, Jacqueline E; Vernacchio, Victoria R; Collins, Shannon M; Palmer, Michael A; Schmidt, Samuel; Antoniewicz, Maciek R; Koffas, Mattheos A; Papoutsakis, Eleftherios T

    2017-01-01

    Methanol is an attractive substrate for biological production of chemicals and fuels. Engineering methylotrophic Escherichia coli as a platform organism for converting methanol to metabolites is desirable. Prior efforts to engineer methylotrophic E. coli were limited by methanol dehydrogenases (Mdhs) with unfavorable enzyme kinetics. We engineered E. coli to utilize methanol using a superior NAD-dependent Mdh from Bacillus stearothermophilus and ribulose monophosphate (RuMP) pathway enzymes from B. methanolicus. Using (13)C-labeling, we demonstrate this E. coli strain converts methanol into biomass components. For example, the key TCA cycle intermediates, succinate and malate, exhibit labeling up to 39%, while the lower glycolytic intermediate, 3-phosphoglycerate, up to 53%. Multiple carbons are labeled for each compound, demonstrating a cycling RuMP pathway for methanol assimilation to support growth. By incorporating the pathway to synthesize the flavanone naringenin, we demonstrate the first example of in vivo conversion of methanol into a specialty chemical in E. coli. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  19. First Report of Klebsiella pneumoniae-Carbapenemase-3-Producing Escherichia coli ST479 in Poland

    Directory of Open Access Journals (Sweden)

    Dominika Ojdana

    2015-01-01

    Full Text Available An increase in the antibiotic resistance among members of the Enterobacteriaceae family has been observed worldwide. Multidrug-resistant Gram-negative rods are increasingly reported. The treatment of infections caused by Escherichia coli and other Enterobacteriaceae has become an important clinical problem associated with reduced therapeutic possibilities. Antimicrobial carbapenems are considered the last line of defense against multidrug-resistant Gram-negative bacteria. Unfortunately, an increase of carbapenem resistance due to the production of Klebsiella pneumoniae carbapenemase (KPC enzymes has been observed. In this study we describe the ability of E. coli to produce carbapenemase enzymes based on the results of the combination disc assay with boronic acid performed according to guidelines established by the European Community on Antimicrobial Susceptibility Testing (EUCAST and the biochemical Carba NP test. Moreover, we evaluated the presence of genes responsible for the production of carbapenemases (blaKPC, blaVIM, blaIMP, blaOXA-48 and genes encoding other β-lactamases (blaSHV, blaTEM, blaCTX-M among E. coli isolate. The tested isolate of E. coli that possessed the blaKPC-3 and blaTEM-34 genes was identified. The tested strain exhibited susceptibility to colistin (0.38 μg/mL and tigecycline (1 μg/mL. This is the first detection of blaKPC-3 in an E. coli ST479 in Poland.

  20. Pressure and temperature dependence of growth and morphology of Escherichia coli: Experiments and Stochastic Model

    CERN Document Server

    Kumar, Pradeep

    2012-01-01

    We have investigated the growth of Escherichia coli E.coli, a mesophilic bacterium, as a function of pressure $P$ and temperature $T$. E.coli can grow and divide in a wide range of pressure (1-400atm) and temperature ($23-40^{\\circ}$C). For $T>30^{\\circ}$ C, the division time of E.coli increases exponentially with pressure and exhibit a departure from exponential behavior at pressures between 250-400 atm for all the temperatures studied in our experiments. For $T<30^{\\circ}$ C, the division time shows an anomalous dependence on pressure -- first decreases with increasing pressure and then increases upon further increase of pressure. The sharp change in division time is followed by a sharp change in phenotypic transition of E. Coli at high pressures where bacterial cells switch to an elongating cell type. We propose a model that this phenotypic changes in bacteria at high pressures is an irreversible stochastic process whereas the switching probability to elongating cell type increases with increasing press...

  1. Decolorizing kinetics of a recombinant Escherichia coli SS125 strain harboring azoreductase gene from Bacillus latrosporus RRK1.

    Science.gov (United States)

    Sandhya, S; Sarayu, K; Uma, B; Swaminathan, K

    2008-05-01

    PCR amplified product containing gene responsible for dye decolorization was cloned and expressed in Escherichia coli. The resulting recombinant strain E. coli SS125 decolorized 200mg/l azo dye (Remazol Red) at 30 degrees C at 255 mg cell/l/h, while the host E. coli (DH5 alpha) had no color removal ability. The dependence of the decolorization rate on initial dye concentration and the maximum rate occurred with the dye at 100 mg l(-1). The decolorization rate of E. coli SS125 was optimal at 37-45 degrees C. Aeration strongly-inhibited the decolorization, but decolorization occurred effectively under static and anaerobic incubation conditions. The E. coli SS125 strain also exhibited excellent stability during reported batch operation.

  2. Polyelectrolyte-Functionalized Nanofiber Mats Control the Collection and Inactivation of Escherichia coli

    Directory of Open Access Journals (Sweden)

    Katrina A. Rieger

    2016-04-01

    Full Text Available Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes: poly (acrylic acid (PAA, chitosan (CS, and polydiallyldimethylammonium chloride (pDADMAC. The polyelectrolyte functionalized nanofiber mats retained the cylindrical morphology and average fiber diameter (~0.84 µm of the underlying cellulose nanofibers. X-ray photoelectron spectroscopy (XPS and contact angle measurements confirmed the presence of polycations or polyanions on the surface of the nanofiber mats. Both the control cellulose and pDADMAC-functionalized nanofiber mats exhibited a high collection of E. coli K12, which suggests that mat hydrophilicity may play a larger role than surface charge on cell collection. While the minimum concentration of polycations needed to inhibit E. coli K12 was 800 µg/mL for both CS and pDADMAC, once immobilized, pDADMAC-functionalized nanofiber mats exhibited a higher inactivation of E. coli K12, (~97%. Here, we demonstrate that the collection and inactivation of microorganisms by electrospun cellulose nanofiber mats can be tailored through a facile polyelectrolyte functionalization process.

  3. Silver-modified clinoptilolite for the removal of Escherichia coli and heavy metals from aqueous solutions.

    Science.gov (United States)

    Akhigbe, Lulu; Ouki, Sabeha; Saroj, Devendra; Lim, Xiang Min

    2014-09-01

    This paper investigates the potential of using the silver antibacterial properties combined with the metal ion exchange characteristics of silver-modified clinoptilolite to produce a treatment system capable of removing both contaminants from aqueous streams. The results have shown that silver-modified clinoptilolite is capable of completely eliminating Escherichia coli after 30-min contact time demonstrating its effectiveness as a disinfectant. Systems containing both E. coli and metals exhibited 100 % E. coli reduction after 15-min contact time and maximum metal adsorption removal efficiencies of 97, 98, and 99 % for Pb(2+), Cd(2+), and Zn(2+) respectively after 60 min; 0.182-0.266 mg/g of metal ions were adsorbed by the zeolites in the single- and mixed-metal-containing solutions. Nonmodified clinoptilolite showed no antibacterial properties. This study demonstrated that silver-modified clinoptilolite exhibited high disinfection and heavy metal removal efficiencies and consequently could provide an effective combined treatment system for the removal of E. coli and metals from contaminated water streams.

  4. Characterization of pyruvate uptake in Escherichia coli K-12.

    Directory of Open Access Journals (Sweden)

    Jens Kreth

    Full Text Available The monocarboxylate pyruvate is an important metabolite and can serve as sole carbon source for Escherichia coli. Although specific pyruvate transporters have been identified in two bacterial species, pyruvate transport is not well understood in E. coli. In the present study, pyruvate transport was investigated under different growth conditions. The transport of pyruvate shows specific activities depending on the growth substrate used as sole carbon source, suggesting the existence of at least two systems for pyruvate uptake: i one inducible system and probably highly specific for pyruvate and ii one system active under non-induced conditions. Using the toxic pyruvate analog 3-fluoropyruvate, a mutant was isolated unable to grow on and transport pyruvate. Further investigation revealed that a revertant selected for growth on pyruvate regained the inducible pyruvate transport activity. Characterization of pyruvate excretion showed that the pyruvate transport negative mutant accumulated pyruvate in the growth medium suggesting an additional transport system for pyruvate excretion. The here presented data give valuable insight into the pyruvate metabolism and transport of E. coli suggesting the presence of at least two uptake systems and one excretion system to balance the intracellular level of pyruvate.

  5. CHARACTERIZATION AND ANTIBIOGRAM OF ENTEROPATHOGENIC ESCHERICHIA COLI ISOLATED FROM POULTRY

    Directory of Open Access Journals (Sweden)

    M. Sarkar

    2013-12-01

    Full Text Available One hundred sixty two samples from different poultry farms of West Bengal, India were screened for the presence of pathogenic Escherichia coli and 109 (67.3% were found positive. Out of forty six faecal samples from ailing birds suffering from acute colibacillosis, thirty one i.e. 67.2% were positive whereas postmortem sample of intestines (62 and liver tissues (54 revealed approx 72.6% and 61.1% positivity for E. coli. Biochemical characteristic of the isolates were positive to indole, MR, nitrate and non-reactive to VP, citrate & urease test. In serotyping of the E. coli isolates mostly revealed O2, O8, O9, O19, O37, O47, O55, O69, O86, O101, O103, O109, O133, O151 and O173. The serotypes viz. O2, O8, O9, O55, O101 and O133 showed acute pathogenicity in swiss mice followed by O19, O37, O47, O69, O86, O103, O109, O151 and O173 as moderately pathogenic serotypes. Among the antimicrobial drugs tested, the sensitive drugs were cefixime (93.6%, enrofloxacin (91.8%, nitrofurantoin (88.1% and azithromycin (85.3%. The resistant drugs were tetracycline (100%, nalidixic acid (97.2%, metronidazole (92.6%, penicillin G (88.9%, gatifloxacin (77.9% and bacitracin (76.2% .

  6. Identification of diarrheagenic Escherichia coli strains from avian organic fertilizers.

    Science.gov (United States)

    Puño-Sarmiento, Juan; Gazal, Luis Eduardo; Medeiros, Leonardo P; Nishio, Erick K; Kobayashi, Renata K T; Nakazato, Gerson

    2014-08-28

    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.

  7. Butyrate production under aerobic growth conditions by engineered Escherichia coli.

    Science.gov (United States)

    Kataoka, Naoya; Vangnai, Alisa S; Pongtharangkul, Thunyarat; Yakushi, Toshiharu; Matsushita, Kazunobu

    2017-05-01

    Butyrate is an important industrial platform chemical. Although several groups have reported butyrate production under oxygen-limited conditions by a native producer, Clostridium tyrobutylicum, and by a metabolically engineered Escherichia coli, efforts to produce butyrate under aerobic growth conditions have met limited success. Here, we constructed a novel butyrate synthetic pathway that functions under aerobic growth conditions in E. coli, by modifying the 1-butanol synthetic pathway reported previously. The pathway consists of phaA (acetyltransferase) and phaB (NADPH-dependent acetoacetyl-CoA reductase) from Ralstonia eutropha, phaJ ((R)-specific enoyl-CoA hydratase) from Aeromonas caviae, ter (trans-enoyl-CoA reductase) from Treponema denticola, and endogenous thioesterase(s) of E. coli. To evaluate the potential of this pathway for butyrate production, culture conditions, including pH, oxygen supply, and concentration of inorganic nitrogen sources, were optimized in a mini-jar fermentor. Under the optimal conditions, butyrate was produced at a concentration of up to 140 mM (12.3 g/L in terms of butyric acid) after 54 h of fed-batch culture. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  8. Escherichia coli lipoprotein binds human plasminogen via an intramolecular domain

    Directory of Open Access Journals (Sweden)

    Tammy eGonzalez

    2015-10-01

    Full Text Available Escherichia coli lipoprotein (Lpp is a major cellular component that exists in two distinct states, bound-form and free-form. Bound-form Lpp is known to interact with the periplasmic bacterial cell wall, while free-form Lpp is localized to the bacterial cell surface. A function for surface-exposed Lpp has yet to be determined. We hypothesized that the presence of C-terminal lysines in the surface-exposed region of Lpp would facilitate binding to the host zymogen plasminogen, a protease commandeered by a number of clinically important bacteria. Recombinant Lpp was synthesized and the binding of Lpp to plasminogen, the effect of various inhibitors on this binding, and the effects of various mutations of Lpp on Lpp-plasminogen interactions were examined. Additionally, the ability of Lpp-bound plasminogen to be converted to active plasmin was analyzed. We determined that Lpp binds plasminogen via an atypical domain located near the center of mature Lpp that may not be exposed on the surface of intact E. coli according to the current localization model. Finally, we found that plasminogen bound by Lpp can be converted to active plasmin. While the consequences of Lpp binding plasminogen are unclear, these results prompt further investigation of the ability of surface exposed Lpp to interact with host molecules such as extracellular matrix components and complement regulators, and the role of these interactions in infections caused by E. coli and other bacteria.

  9. Global functional atlas of Escherichia coli encompassing previously uncharacterized proteins.

    Directory of Open Access Journals (Sweden)

    Pingzhao Hu

    2009-04-01

    Full Text Available One-third of the 4,225 protein-coding genes of Escherichia coli K-12 remain functionally unannotated (orphans. Many map to distant clades such as Archaea, suggesting involvement in basic prokaryotic traits, whereas others appear restricted to E. coli, including pathogenic strains. To elucidate the orphans' biological roles, we performed an extensive proteomic survey using affinity-tagged E. coli strains and generated comprehensive genomic context inferences to derive a high-confidence compendium for virtually the entire proteome consisting of 5,993 putative physical interactions and 74,776 putative functional associations, most of which are novel. Clustering of the respective probabilistic networks revealed putative orphan membership in discrete multiprotein complexes and functional modules together with annotated gene products, whereas a machine-learning strategy based on network integration implicated the orphans in specific biological processes. We provide additional experimental evidence supporting orphan participation in protein synthesis, amino acid metabolism, biofilm formation, motility, and assembly of the bacterial cell envelope. This resource provides a "systems-wide" functional blueprint of a model microbe, with insights into the biological and evolutionary significance of previously uncharacterized proteins.

  10. Characterization of the YdeO regulon in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Yuki Yamanaka

    Full Text Available Enterobacteria are able to survive under stressful conditions within animals, such as acidic conditions in the stomach, bile salts during transfer to the intestine and anaerobic conditions within the intestine. The glutamate-dependent (GAD system plays a major role in acid resistance in Escherichia coli, and expression of the GAD system is controlled by the regulatory cascade consisting of EvgAS > YdeO > GadE. To understand the YdeO regulon in vivo, we used ChIP-chip to interrogate the E. coli genome for candidate YdeO binding sites. All of the seven operons identified by ChIP-chip as being potentially regulated by YdeO were confirmed as being under the direct control of YdeO using RT-qPCR, EMSA, DNaseI-footprinting and reporter assays. Within this YdeO regulon, we identified four stress-response transcription factors, DctR, NhaR, GadE, and GadW and enzymes for anaerobic respiration. Both GadE and GadW are involved in regulation of the GAD system and NhaR is an activator for the sodium/proton antiporter gene. In conjunction with co-transcribed Slp, DctR is involved in protection against metabolic endoproducts under acidic conditions. Taken all together, we suggest that YdeO is a key regulator of E. coli survival in both acidic and anaerobic conditions.

  11. Reductive transformation of TNT by Escherichia coli: pathway description.

    Science.gov (United States)

    Yin, Hong; Wood, Thomas K; Smets, Barth F

    2005-05-01

    The reductive transformation of 2,4,6-trinitrotoluene (TNT) was studied using aerobically grown Escherichia coli cultures. In the absence of an external carbon or energy source, E. coli resting cells transformed TNT to hydroxylaminodinitrotoluenes (2HADNT, 4HADNT, with 4HADNT as the dominant isomer), aminodinitrotoluenes (4ADNT, with sporadic detection of 2ADNT), 2,4-di(hydroxylamino)-6-nitrotoluene (24D(HA)6NT), 2,4-diamino-6-nitrotoluene (24DA6NT), and an additional compound which was tentatively identified as a (hydroxylamino)aminonitrotoluene isomer via gas chromatography/mass spectroscopy and spectral analysis. The resting cell assay, performed in an oxygen-free atmosphere, avoided formation of azoxy dimers and provided good mass balances. Significant preference for reduction in the para versus ortho position was detected. The formation of 24D(HA)6NT, but not ADNT, appeared inhibited by the presence of TNT. The rate and extent of TNT reduction were significantly enhanced at higher cell densities, or by supplying an exogenous reducing power source, revealing the importance of enzyme concentration and reducing power. Whether the oxygen-insensitive E. coli nitroreductases, encoded by nfsA and nfsB, directly catalyze the TNT reduction or account for the complete TNT transformation pathway, remains to be determined.

  12. 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.

  13. Virulence genes of Escherichia coli strains isolated from mastitic milk.

    Science.gov (United States)

    Bean, A; Williamson, J; Cursons, R T

    2004-08-01

    Escherichia coli, a Gram-negative environmental pathogen associated with bovine mastitis was isolated from the milk of 34 symptomatic cows that had been diagnosed with clinical mastitis. Eighty isolates were obtained over a 17-month period and these isolates were screened by DNA amplification for the following E. coli virulence genes: cnf1, cnf2, eaeA, eagg, einv, ltx1, stx1, stx2 and vt2e. Thirty of the bacterial isolates, obtained from 23 different cows, had toxin genes identified in their DNA. The most common virulence gene detected was stx1, with a prevalence of 31%, followed by cnf2 (7.5%), vt2e (6.25%) and eaeA (4%). The possession of different virulence genes by the bacterial isolates had no discernable impact on the health status of the cows as there was no correlation between the potential for toxin production by the E. coli isolates and the systemic clinical condition of the respective infected cows.

  14. Adenosine diphosphate sugar pyrophosphatase prevents glycogen biosynthesis in Escherichia coli

    Science.gov (United States)

    Moreno-Bruna, Beatriz; Baroja-Fernández, Edurne; Muñoz, Francisco José; Bastarrica-Berasategui, Ainara; Zandueta-Criado, Aitor; Rodríguez-López, Milagros; Lasa, Iñigo; Akazawa, Takashi; Pozueta-Romero, Javier

    2001-01-01

    An adenosine diphosphate sugar pyrophosphatase (ASPPase, EC 3.6.1.21) has been characterized by using Escherichia coli. This enzyme, whose activities in the cell are inversely correlated with the intracellular glycogen content and the glucose concentration in the culture medium, hydrolyzes ADP-glucose, the precursor molecule of glycogen biosynthesis. ASPPase was purified to apparent homogeneity (over 3,000-fold), and sequence analyses revealed that it is a member of the ubiquitously distributed group of nucleotide pyrophosphatases designated as “nudix” hydrolases. Insertional mutagenesis experiments leading to the inactivation of the ASPPase encoding gene, aspP, produced cells with marginally low enzymatic activities and higher glycogen content than wild-type bacteria. aspP was cloned into an expression vector and introduced into E. coli. Transformed cells were shown to contain a dramatically reduced amount of glycogen, as compared with the untransformed bacteria. No pleiotropic changes in the bacterial growth occurred in both the aspP-overexpressing and aspP-deficient strains. The overall results pinpoint the reaction catalyzed by ASPPase as a potential step of regulating glycogen biosynthesis in E. coli. PMID:11416161

  15. Escherichia coli Meningitis after Rotavirus Gastroenteritis in an Infant.

    Science.gov (United States)

    Ozgurhan, Gamze; Vermezoglu, Oznur; Ocal Topcu, Didem; Karbuz, Adem; Vehapoglu, Aysel; Hacihamdioglu, Bulent

    2016-01-01

    Although rotavirus gastroenteritis is quite common in the pediatric population, secondary bacterial sepsis following rotavirus infection is a rare clinical entity. Gram-negative bacilli are the fifth most common cause of meningitis in infants but this infection rarely occurs after gastroenteritis. Here, we report a 2.5-month-old infant who developed Escherichia coli (E. coli) meningitis after acute rotavirus gastroenteritis. The 2.5-month-old male infant with fever, vomiting, and watery diarrhea that started 1 day earlier was admitted to the hospital. Rotavirus antigen in stool sample was positive. He was hospitalized, and fever was measured at 39.5°C on the second day. Lumbar puncture was done for suspicion of meningitis, and cerebrospinal fluid (CSF) findings suggested meningitis. Intravenous vancomycin and cefotaxime were started empirically. Since E. coli reproduction was seen in blood culture and CSF culture, treatment was continued with cefotaxime. The patient was discharged with minimal midlevel hydrocephalus findings in cranial ultrasonography and magnetic resonance imaging following 21 days of antibiotics treatment. Septicemia development following rotavirus gastroenteritis is an extremely rare clinical condition. It is vital to start prompt antibiotic treatment as soon as the diagnosis of secondary bacterial infection is made because of high mortality and morbidity rates.

  16. Escherichia coli Meningitis after Rotavirus Gastroenteritis in an Infant

    Directory of Open Access Journals (Sweden)

    Gamze Ozgurhan

    2016-01-01

    Full Text Available Although rotavirus gastroenteritis is quite common in the pediatric population, secondary bacterial sepsis following rotavirus infection is a rare clinical entity. Gram-negative bacilli are the fifth most common cause of meningitis in infants but this infection rarely occurs after gastroenteritis. Here, we report a 2.5-month-old infant who developed Escherichia coli (E. coli meningitis after acute rotavirus gastroenteritis. The 2.5-month-old male infant with fever, vomiting, and watery diarrhea that started 1 day earlier was admitted to the hospital. Rotavirus antigen in stool sample was positive. He was hospitalized, and fever was measured at 39.5°C on the second day. Lumbar puncture was done for suspicion of meningitis, and cerebrospinal fluid (CSF findings suggested meningitis. Intravenous vancomycin and cefotaxime were started empirically. Since E. coli reproduction was seen in blood culture and CSF culture, treatment was continued with cefotaxime. The patient was discharged with minimal midlevel hydrocephalus findings in cranial ultrasonography and magnetic resonance imaging following 21 days of antibiotics treatment. Septicemia development following rotavirus gastroenteritis is an extremely rare clinical condition. It is vital to start prompt antibiotic treatment as soon as the diagnosis of secondary bacterial infection is made because of high mortality and morbidity rates.

  17. Metabolic engineering of Escherichia coli for the production of xylonate.

    Directory of Open Access Journals (Sweden)

    Yujin Cao

    Full Text Available Xylonate is a valuable chemical for versatile applications. Although the chemical synthesis route and microbial conversion pathway were established decades ago, no commercial production of xylonate has been obtained so far. In this study, the industrially important microorganism Escherichia coli was engineered to produce xylonate from xylose. Through the coexpression of a xylose dehydrogenase (xdh and a xylonolactonase (xylC from Caulobacter crescentus, the recombinant strain could convert 1 g/L xylose to 0.84 g/L xylonate and 0.10 g/L xylonolactone after being induced for 12 h. Furthermore, the competitive pathway for xylose catabolism in E. coli was blocked by disrupting two genes (xylA and xylB encoding xylose isomerase and xylulose kinase. Under fed-batch conditions, the finally engineered strain produced up to 27.3 g/L xylonate and 1.7 g/L xylonolactone from 30 g/L xylose, about 88% of the theoretical yield. These results suggest that the engineered E. coli strain has a promising perspective for large-scale production of xylonate.

  18. Shiga Toxin (Verotoxin)-Producing Escherichia coli in Japan.

    Science.gov (United States)

    Terajima, Jun; Iyoda, Sunao; Ohnishi, Makoto; Watanabe, Haruo

    2014-10-01

    A series of outbreaks of infection with Shiga toxin (verocytotoxin)-producing Escherichia coli or enterohemorrhagic E. coli (EHEC) O157:H7 occurred in Japan in 1996, the largest outbreak occurring in primary schools in Sakai City, Osaka Prefecture, where more than 7,500 cases were reported. Although the reason for the sudden increase in the number of reports of EHEC isolates in 1996 is not known, the number of reports has grown to more than 3,000 cases per year since 1996, from an average of 105 reports each year during the previous 5-year period (1991-1995). Despite control measures instituted since 1996, including designating Shiga toxin-producing E. coli infection as a notifiable disease, and nationwide surveillance effectively monitoring the disease, the number of reports remains high, around 3,800 cases per year. Serogroup O157 predominates over other EHEC serogroups, but isolation frequency of non-O157 EHEC has gone up slightly over the past few years. Non-O157 EHEC has recently caused outbreaks where consumption of a raw beef dish was the source of the infection, and some fatal cases occurred. Laboratory surveillance comprised prefectural and municipal public health institutes, and the National Institute of Infectious Diseases has contributed to finding not only multiprefectural outbreaks but recognizing sporadic cases that could have been missed as an outbreak without the aid of molecular subtyping of EHEC isolates. This short overview presents recent information on the surveillance of EHEC infections in Japan.

  19. Antimicrobial Resistance Pattern of Pathogenic Escherichia coli Isolated from Chicken Liver and Trachea

    OpenAIRE

    Atere, V. A.

    2015-01-01

    Escherichia coli is a poultry bacterial pathogen reported for causing a wide variety of disease. The aim of this research was to determine the antibiotic susceptibility of pathogenic Escherichia coli isolated from liver and trachea of freshly dead chicken. Ninety seven (97) freshly dead chicken from 23 different farms where analyzed for the presence of pathogenic E. coli. In vitro susceptibility of the isolates against antimicrobial agents was determined using disk diffusion method. A total o...

  20. Escherichia coli: a brief review of diarrheagenic pathotypes and their role in diarrheal diseases in Iran

    Science.gov (United States)

    Jafari, A; Aslani, MM; Bouzari, S

    2012-01-01

    Diarrheagenic Escherichia coli have developed different strategies for establishment of infection in their host. Understanding these pathogenic mechanisms has led to the development of specific diagnostic tools for identification and categorization of E. coli strains into different pathotypes. This review aims to provide an overview of the various categories of diarrheagenic Escherichia coli and the data obtained in Iran pertaining to these pathotypes. PMID:23066484

  1. Characterization of Enterohemorrhagic Escherichia coli on Veal Hides and Carcasses.

    Science.gov (United States)

    Bosilevac, Joseph M; Wang, Rong; Luedtke, Brandon E; Hinkley, Susanne; Wheeler, Tommy L; Koohmaraie, Mohammad

    2017-01-01

    Enterohemorrhagic Escherichia coli (EHEC) are Shiga toxin-producing E. coli associated with the most severe forms of foodborne illnesses. The U.S. Department of Agriculture, Food Safety and Inspection Service has identified a higher percentage of non-O157 EHEC compared with E. coli O157:H7-positive samples collected from veal trimmings than from products produced from other cattle slaughter classes. Therefore samples were collected from hides and preevisceration carcasses at five veal processors to assess E. coli O157:H7 and non-O157 EHEC contamination during bob veal and formula-fed veal dressing procedures. E. coli O157:H7 prevalence was measured by culture isolation and found to be on 20.3% of hides and 6.7% of carcasses. In contrast, a non-O157 EHEC molecular screening assay identified 90.3% of hides and 68.2% of carcasses as positive. Only carcass samples were taken forward to culture confirmation and 38.7% yielded one or more non-O157 EHEC isolates. The recovery of an EHEC varied by plant and sample collection date; values ranged from 2.1 to 87.8% among plants and from 4.2 to 64.2% within the same plant. Three plants were resampled after changes were made to sanitary dressing procedures. Between the two collection times at the three plants, hide-to-carcass transfer of E. coli O157:H7 and non-O157 EHEC was significantly reduced. All adulterant EHEC serogroups (O26, O45, O103, O111, O121, and O145) were isolated from veal carcasses as well as four other potentially pathogenic serogroups (O5, O84, O118, and O177). Bob veal was found to have a greater culture prevalence of E. coli O157:H7 and greater positive molecular screens for non-O157 EHEC than formula-fed veal (P EHEC was not different (P > 0.05) between the two types of calves. EHEC-O26, -O111, and -O121 were found more often in bob veal (P EHEC-O103 was found more often in formula-fed veal (P < 0.05).

  2. Environmental reservoirs for enterotoxigenic Escherichia coli in south Asian Gangetic riverine system.

    Science.gov (United States)

    Singh, Gulshan; Vajpayee, Poornima; Ram, Siya; Shanker, Rishi

    2010-08-15

    Forecasting diarrheagenic E. coli contamination of aquatic resources to prevent outbreaks largely depends on rapid and accurate diagnostic testing in a few hours. Real-time PCR is widely used for quick culture-free quantitative enumeration of pathogenic bacteria in environmental samples. In this study, real-time PCR in molecular beacon format was used for detection and culture-free quantitative enumeration of enterotoxigenic Escherichia coli (ETEC) harboring LT1 gene in a sewage-impacted south Asian Gangetic riverine system. The quantitative budget for ETEC in surface water was observed to vary significantly (DMRT, p Pontederia cordata, Najas indica and strands of Spirogyra spp.) collected between sites 1 and 9 exhibited significant high levels of ETEC in comparison to their representatives collected from pristine area. The level of ETEC harboring LT1 gene observed in leafy vegetables cultivated along the banks was in the following order: mint leaves > coriander > spinach > methi leaves. The study suggests that the aquatic flora and cultivated leafy vegetables in the south Asian Gangetic riverine system are environmental reservoirs for enterotoxigenic Escherichia coli.

  3. Transferability of antimicrobial resistance from multidrug-resistant Escherichia coli isolated from cattle in the United States to Escherichia coli and Salmonella Newport recipients

    Science.gov (United States)

    The objective of this study was to evaluate conjugative transfer of cephalosporin resistance among (n=100) strains of multi-drug resistant Escherichia coli (MDRE) to Salmonella Newport and E. coli DH5-alpha recipients. To accomplish this, phenotypic and genotypic profiles were determined for MDRE, ...

  4. Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam.

    Science.gov (United States)

    Trung, Nguyen Vinh; Nhung, Hoang Ngoc; Carrique-Mas, Juan J; Mai, Ho Huynh; Tuyen, Ha Thanh; Campbell, James; Nhung, Nguyen Thi; Van Minh, Pham; Wagenaar, Jaap A; Mai, Nguyen Thi Nhu; Hieu, Thai Quoc; Schultsz, Constance; Hoa, Ngo Thi

    2016-09-09

    Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an outbreak of E. coli O104:H4 in Europe in 2011. We assessed the opportunities for E. coli carrying the aggR and stx genes to emerge in 'backyard' farms in south-east Asia. Faecal samples collected from 204 chicken farms; 204 farmers and 306 age- and gender-matched individuals not exposed to poultry farming were plated on MacConkey agar plates with and without antimicrobials being supplemented. Sweep samples obtained from MacConkey agar plates without supplemented antimicrobials were screened by multiplex PCR for the detection of the stx1, stx2 and aggR genes. One chicken farm sample each (0.5 %) contained the stx1 and the aggR gene. Eleven (2.4 %) human faecal samples contained the stx1 gene, 2 samples (0.4 %) contained stx2 gene, and 31 (6.8 %) contained the aggR gene. From 46 PCR-positive samples, 205 E. coli isolates were tested for the presence of stx1, stx2, aggR, wzx O104 and fliC H4 genes. None of the isolates simultaneously contained the four genetic markers associated with E. coli O104:H4 epidemic strain (aggR, stx2, wzx O104 and fliC H4 ). Of 34 EAEC, 64.7 % were resistant to 3(rd)-generation cephalosporins. These results indicate that in southern Vietnam, the human population is a more likely reservoir of aggR and stx gene carrying E. coli than the chicken population. However, conditions for transmission of isolates and/or genes between human and animal reservoirs resulting in the emergence of highly virulent E. coli strains are still favorable, given the nature of'backyard' farms in Vietnam.

  5. Deoxysugar pathway interchange for erythromycin analogues heterologously produced through Escherichia coli.

    Science.gov (United States)

    Jiang, Ming; Zhang, Haoran; Park, Sung-Hee; Li, Yi; Pfeifer, Blaine A

    2013-11-01

    The overall erythromycin biosynthetic pathway can be sub-divided into macrocyclic polyketide formation and polyketide tailoring to produce the final bioactive molecule. In this study, the native deoxysugar tailoring reactions were exchanged for the purpose of demonstrating the production of alternative final erythromycin compounds. Both the d-desosamine and l-mycarose deoxysugar pathways were replaced with the alternative d-mycaminose and d-olivose pathways to produce new erythromycin analogues through the Escherichia coli heterologous system. Both analogues exhibited bioactivity against multiple antibiotic-resistant Bacillus subtilis strains. Besides demonstrating an intrinsic flexibility for the biosynthetic system to accommodate alternative tailoring pathways, the results offer an initial attempt to leverage the E. coli platform for erythromycin analogue production. © 2013 Elsevier Inc. All rights reserved.

  6. Coenzyme precursor-assisted expression of a cholesterol oxidase from Brevibacterium sp. in Escherichia coli.

    Science.gov (United States)

    Wang, Longgang; Wang, Wu

    2007-05-01

    The gene (choB(b)), encoding cholesterol oxidase from Brevibacterium sp. CCTCC M201008, was cloned and sequenced by PCR (GenBank accession number: DQ345780). The gene consists of 1653 base pairs and encodes a protein of 551 amino acids. ChoB(b) exhibited a homology of 98% with cholesterol oxidase gene from Brevibacterium sterolicum ATCC 21387. The cholesterol oxidase gene, cloned in the vector pET-28a, was over-expressed in Escherichia coli BL21-CodonPlus (DE3)-RP grown at 23 degrees C in Luria-Bertani medium containing 50 microM riboflavin, the precursor of the FAD coenzyme of the enzyme. A maximum activity of 3.7 U/mg was obtained from cell free extract of E. coli BL21-CodonPlus (DE3)-RP harboring the pET-28a-choB(b).

  7. Metabolic engineering of Escherichia coli for acetaldehyde overproduction using pyruvate decarboxylase from Zymomonas mobilis.

    Science.gov (United States)

    Balagurunathan, Balaji; Tan, Lily; Zhao, Hua

    2018-02-01

    For the sustainable production of acetaldehyde, a key raw-material for a large number of chemical products, microbial production is a promising alternative. We have engineered an Escherichia coli strain for acetaldehyde production from glucose by introducing the pyruvate decarboxylase (Pdc) from Zymomonas mobilis and NADH oxidase (Nox) from Lactococcus lactis. Acetaldehyde production was systematically improved by knocking out the competing metabolic pathways. Multiple knockout strains were created and a final acetaldehyde titre of 0.73g/L was achieved using a quadruple knockout strain E. coli MC4100 ΔadhE ΔldhA ΔfrdC ΔackA-pta. In addition to acetaldehyde, about 0.37g/L acetoin was produced by these strains due to the additional carboligase activity exhibited by pyruvate decarboxylase resulting in a total carbon yield of 0.27g/g glucose. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Comparison of cellular stress levels and green-fluorescent-protein expression in several Escherichia coli strains.

    Science.gov (United States)

    Seo, Jeong Hyun; Kang, Dong Gyun; Cha, Hyung Joon

    2003-04-01

    Constructs comprising stress-gene promoter elements from rpoH (Sigma 32), clpB or dnaK linked to a green-fluorescent-protein (GFP) expression vector were previously used as non-invasive "stress probes" in Escherichia coli. We compared cellular stress responses in four E. coli strains: production hosts JM105 and BL21, and cloning hosts HB101 and TOP10. When GFP was also used as a model for foreign protein production, we generally observed that the level of expression was inversely proportional to the level of cellular stress. JM105 showed the highest cellular stress level and very low GFP expression, while BL21 exhibited the lowest cellular stress level and the highest GFP expression, in both normal and heat-shock stress environments.

  9. Cross-Reactive Protection against Enterohemorrhagic Escherichia coli Infection by Enteropathogenic E. coli in a Mouse Model ▿

    Science.gov (United States)

    Calderon Toledo, Carla; Arvidsson, Ida; Karpman, Diana

    2011-01-01

    Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) are related attaching and effacing (A/E) pathogens. The genes responsible for the A/E pathology are carried on a chromosomal pathogenicity island termed the locus of enterocyte effacement (LEE). Both pathogens share a high degree of homology in the LEE and additional O islands. EHEC prevalence is much lower in areas where EPEC is endemic. This may be due to the development of antibodies against common EPEC and EHEC antigens. This study investigated the hypothesis that EPEC infections may protect against EHEC infections. We used a mouse model to inoculate BALB/c mice intragastrically, first with EPEC and then with EHEC (E. coli O157:H7). Four control groups received either a nonpathogenic E. coli (NPEC) strain followed by EHEC (NPEC/EHEC), phosphate-buffered saline (PBS) followed by EHEC (PBS/EHEC), EPEC/PBS, or PBS/PBS. Mice were monitored for weight loss and symptoms. EPEC colonized the intestine after challenge, and mice developed serum antibodies to intimin and E. coli secreted protein B (encoded in the LEE). Prechallenge with an EPEC strain had a protective effect after EHEC infection, as only a few mice developed mild symptoms, from which they recovered. These mice had an increase in body weight similar to that in control animals, and tissue morphology exhibited mild intestinal changes and normal renal histology. All mice that were not prechallenged with the EPEC strain developed mild to severe symptoms after EHEC infection, with weight loss as well as intestinal and renal histopathological changes. These data suggest that EPEC may protect against EHEC infection in this mouse model. PMID:21402761

  10. Characterization of Urinary Tract Infection-Associated Shiga Toxin-Producing Escherichia coli

    Science.gov (United States)

    Toval, Francisco; Schiller, Roswitha; Meisen, Iris; Putze, Johannes; Kouzel, Ivan U.; Zhang, Wenlan; Karch, Helge; Bielaszewska, Martina; Mormann, Michael; Müthing, Johannes

    2014-01-01

    Enterohemorrhagic Escherichia coli (EHEC), a subgroup of Shiga toxin (Stx)-producing E. coli (STEC), is a leading cause of diarrhea and hemolytic-uremic syndrome (HUS) in humans. However, urinary tract infections (UTIs) caused by this microorganism but not associated with diarrhea have occasionally been reported. We geno- and phenotypically characterized three EHEC isolates obtained from the urine of hospitalized patients suffering from UTIs. These isolates carried typical EHEC virulence markers and belonged to HUS-associated E. coli (HUSEC) clones, but they lacked virulence markers typical of uropathogenic E. coli. One isolate exhibited a localized adherence (LA)-like pattern on T24 urinary bladder epithelial cells. Since the glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer) are well-known receptors for Stx but also for P fimbriae, a major virulence factor of extraintestinal pathogenic E. coli (ExPEC), the expression of Gb3Cer and Gb4Cer by T24 cells and in murine urinary bladder tissue was examined by thin-layer chromatography and mass spectrometry. We provide data indicating that Stxs released by the EHEC isolates bind to Gb3Cer and Gb4Cer isolated from T24 cells, which were susceptible to Stx. All three EHEC isolates expressed stx genes upon growth in urine. Two strains were able to cause UTI in a murine infection model and could not be outcompeted in urine in vitro by typical uropathogenic E. coli isolates. Our results indicate that despite the lack of ExPEC virulence markers, EHEC variants may exhibit in certain suitable hosts, e.g., in hospital patients, a uropathogenic potential. The contribution of EHEC virulence factors to uropathogenesis remains to be further investigated. PMID:25156739

  11. Evaluation of the efficacy of an autogenous Escherichia coli vaccine in broiler breeders

    DEFF Research Database (Denmark)

    Li, Lili; Thøfner, Ida; Christensen, Jens Peter

    2017-01-01

    In poultry production Escherichia coli autogenous vaccines are often used. However, the efficacy of autogenous E. coli vaccinations has not been evaluated experimentally in chickens after start of lay. The aim of the present study was to evaluate the protective effect of an autogenous E. coli vac...

  12. Identification of Genes Important for Growth of Asymptomatic Bacteriuria Escherichia coli in Urine

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; de Evgrafov, Mari Cristina Rodriguez; Phan, Minh Duy

    2012-01-01

    Escherichia coli is the most important etiological agent of urinary tract infections (UTIs). Unlike uropathogenic E. coli, which causes symptomatic infections, asymptomatic bacteriuria (ABU) E. coli strains typically lack essential virulence factors and colonize the bladder in the absence of symp...

  13. Risk factors for ESBL-producing Escherichia coli on pig farms

    NARCIS (Netherlands)

    Dohmen, Wietske; Dorado-García, Alejandro; Bonten, Marc J.M.; Wagenaar, Jaap A.; Mevius, Dik; Heederik, Dick J.J.

    2017-01-01

    The presence of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E. coli) in food animals is a public health concern. This study aimed to determine prevalence of ESBL-E. coli on pig farms and to assess the effect of reducing veterinary antimicrobial use (AMU) and farm management

  14. Comparison of whole genome sequences from human and non-human Escherichia coli O26 strains

    Science.gov (United States)

    Shiga toxin-producing Escherichia coli (STEC) O26 is the second leading E. coli serogroup responsible for human illness outbreaks behind E. coli O157:H7. Recent outbreaks have been linked to emerging pathogenic O26:H11 strains harboring stx2 only. Cattle have been recognized as an important reserv...

  15. 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...

  16. Diet, Escherichia coli O157:H7, and cattle: A review after 10 years

    Science.gov (United States)

    Escherichia coli are commensal bacteria that can account for up to 1% of the bacterial population of the gut. Ruminant animals are reservoirs of the pathogenic bacteria E. coli O157:H7, and approximately 30% of feedlot cattle shed E. coli O157:H7. Feedlot and high-producing dairy cattle are fed hi...

  17. 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...

  18. A rare presentation of ischemic pseudomembranous colitis due to Escherichia coli O157:H7.

    Science.gov (United States)

    Kendrick, Jessica B; Risbano, Michael; Groshong, Steve D; Frankel, Stephen K

    2007-07-15

    Escherichia coli Ol57:H7 infection ranges from mild diarrheal illness to severe hemorrhagic colitis but may rarely be complicated by pseudomembranous colitis and/or necrosis. Herein, we report a sporadic case of ischemic E. coli Ol57:H7 pseudomembranous colitis in an adult that occurred during a national outbreak of E. coli Ol57:H7 in the United States.

  19. Towards understanding inter-strain attachment variations of Escherichia coli during transport in saturated quartz sand.

    NARCIS (Netherlands)

    Foppen, J.W.; Lutterodt, G.; Roling, W.F.M.; Uhlenbrook, S.

    2010-01-01

    Although Escherichia coli is an indicator of fecal contamination in aquifers, limited research has been devoted to understanding the biological processes involved in the initial attachment of E. coli transported in abiotic porous media. The roles of the various surface structures of E. coli, like

  20. Control analysis of the dependence of Escherichia coli physiology on the H+ -ATPase

    DEFF Research Database (Denmark)

    Jensen, Peter Ruhdal; Michelsen, Ole; Westerhoff, Hans V.

    1993-01-01

    The H+-ATPase plays a central role in Escherichia coli free-energy transduction and hence in E. coli physiology. We here investigate the extent to which this enzyme also controls the growth rate, growth yield, and respiratory rate of E. coli. We modulate the expression of the atp operon and deter...

  1. A homolog of an Escherichia coli phosphate-binding protein gene from Xanthomonas oryzae pv. oryzae

    Science.gov (United States)

    Hopkins, C. M.; White, F. F.; Heaton, L. A.; Guikema, J. A.; Leach, J. E.; Spooner, B. S. (Principal Investigator)

    1995-01-01

    A Xanthomonas oryzae pv. oryzae gene with sequence similarity to an Escherichia coli phosphate-binding protein gene (phoS) produces a periplasmic protein of apparent M(r) 35,000 when expressed in E. coli. Amino terminal sequencing revealed that a signal peptide is removed during transport to the periplasm in E. coli.

  2. Kinetic modelling of central carbon metabolism in Escherichia coli.

    Science.gov (United States)

    Peskov, Kirill; Mogilevskaya, Ekaterina; Demin, Oleg

    2012-09-01

    In the present study, we developed a detailed kinetic model of Escherichia coli central carbon metabolism. The main model assumptions were based on the results of metabolic and regulatory reconstruction of the system and thorough model verification with experimental data. The development and verification of the model included several stages, which allowed us to take into account both in vitro and in vivo experimental data and avoid the ambiguity that frequently occurs in detailed models of biochemical pathways. The choice of the level of detail for the mathematical description of enzymatic reaction rates and the evaluation of parameter values were based on available published data. Validation of the complete model of the metabolic pathway describing specific physiological states was based on fluxomics and metabolomics data. In particular, we developed a model that describes aerobic growth of E. coli in continuous culture with a limiting concentration of glucose. Such modification of the model was used to integrate experimental metabolomics data obtained in steady-state conditions for wild-type E. coli and genetically modified strains, e.g. knockout of the pyruvate kinase gene (pykA). Following analysis of the model behaviour, and comparison of the coincidence between predicted and experimental data, it was possible to investigate the functional and regulatory properties of E. coli central carbon metabolism. For example, a novel metabolic regulatory mechanism for 6-phosphogluconate dehydrogenase inhibition by phosphoenolpyruvate was hypothesized, and the flux ratios between the reactions catalysed by enzyme isoforms were predicted. The mathematical model described here has been submitted to the JWS Online Cellular Systems Modelling Database and can be accessed at http://jjj.biochem.sun.ac.za/database/peskov/index.html © 2012 The Authors Journal compilation © 2012 FEBS.

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

    Energy Technology Data Exchange (ETDEWEB)

    Gowers, Glen-Oliver F. [Department of Molecular Biology, Princeton University, Princeton, NJ (United States); Robinson, Jonathan L. [Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ (United States); Brynildsen, Mark P., E-mail: mbrynild@princeton.edu [Department of Molecular Biology, Princeton University, Princeton, NJ (United States); Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ (United States)

    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. -- Highlights: •Carbon source availability is critical to aerobic E. coli NO detoxification. •Carbon source starvation, under NO stress, preserves intracellular NADH levels. •Preservation of NADH depends on starvation-dependent inhibition of Hmp induction.

  4. Engineering an Escherichia coli platform to synthesize designer biodiesels.

    Science.gov (United States)

    Wierzbicki, Michael; Niraula, Narayan; Yarrabothula, Akshitha; Layton, Donovan S; Trinh, Cong T

    2016-04-20

    Biodiesels, fatty acid esters (FAEs), can be synthesized by condensation of fatty acid acyl CoAs and alcohols via a wax ester synthase in living cells. Biodiesels have advantageous characteristics over petrodiesels such as biodegradability, a higher flash point, and less emission. Controlling fatty acid and alcohol moieties are critical to produce designer biodiesels with desirable physiochemical properties (e.g., high cetane number, low kinematic viscosity, high oxidative stability, and low cloud point). Here, we developed a flexible framework to engineer Escherichia coli cell factories to synthesize designer biodiesels directly from fermentable sugars. In this framework, we designed each FAE pathway as a biodiesel exchangeable production module consisting of acyl CoA, alcohol, and wax ester synthase submodules. By inserting the FAE modules in an engineered E. coli modular chassis cell, we generated E. coli cell factories to produce targeted biodiesels (e.g., fatty acid ethyl (FAEE) and isobutyl (FAIbE) esters) with tunable and controllable short-chain alcohol moieties. The engineered E. coli chassis carrying the FAIbE production module produced 54mg/L FAIbEs with high specificity, accounting for>90% of the total synthesized FAEs and ∼4.7 fold increase in FAIbE production compared to the wildtype. Fed-batch cultures further improved FAIbE production up to 165mg/L. By mixing ethanol and isobutanol submodules, we demonstrated controllable production of mixed FAEEs and FAIbEs. We envision the developed framework offers a flexible, alternative route to engineer designer biodiesels with tunable and controllable properties using biomass-derived fermentable sugars. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Virulence associated factors and antibiotic sensitivity pattern of Escherichia coli isolated from cattle and soil

    Directory of Open Access Journals (Sweden)

    Parul

    2014-05-01

    Full Text Available Aim: The present study was conducted to isolate pathogenic Escherichia coli from the faeces of apparently healthy cattle and soil of the farms to determine their susceptibility to commonly used antibiotics. Materials and Methods: A total of 90 samples (70 faecal and 20 soil samples were collected aseptically and processed under required conditions for the isolation of E. coli. To confirm the isolates as E. coli, various biochemical tests like IMViC were performed. To assess the virulence of isolates, they were subjected to Congo red dye assay and hemolysis assay. Antibiotic sensitivity pattern of pathogenic isolates was studied by Disc diffusion method. Results: The prevalence of E. coli was observed to be 85.71% and 20% from the faecal and soil samples, respectively. Based on the phenotypic characteristics on CT SMAC and MUG Sorbitol, none of the isolates were found to be E. coli O157. The percent positivity on Congo red dye assay was 44.28% for faeces and 5% for soil while only faecal E. coli (4.28% were found to be positive for hemolysis assay. The antibiogram of all 35 pathogenic isolates against 8 antibiotics showed that majority of pathogenic strains exhibited high level of sensitivity to Ceftriaxone (95%, Ciprofloxacin (93%, Amikacin (90%, Gentamycin (89% and low level of sensitivity against Ampicillin (8% and Streptomycin (5%. All isolates were 100% resistant to Amoxicillin and Tetracycline. Conclusion: Cattle act as main reservoirs of pathogenic E. coli that may enter the food chain by faecal contamination and pose potential public health hazards.

  6. α-hemolysin from Escherichia coli uses endogenous amplification through P2X receptor activation to induce hemolysis

    DEFF Research Database (Denmark)

    Skals, Marianne Gerberg; Jørgensen, Niklas R; Leipziger, Jens Georg

    2009-01-01

    Escherichia coli is the dominant facultative bacterium in the normal intestinal flora. E. coli is, however, also responsible for the majority of serious extraintestinal infections. There are distinct serotypical differences between facultative and invasive E. coli strains. Invasive strains...

  7. Alpha-hemolysin from Escherichia coli uses endogenous amplification through P2X receptor activation to induce hemolysis

    DEFF Research Database (Denmark)

    Skals, Marianne; Jørgensen, Niklas Rye; Leipziger, Jens

    2009-01-01

    Escherichia coli is the dominant facultative bacterium in the normal intestinal flora. E. coli is, however, also responsible for the majority of serious extraintestinal infections. There are distinct serotypical differences between facultative and invasive E. coli strains. Invasive strains...

  8. The comprehensive updated regulatory network of Escherichia coli K-12

    Directory of Open Access Journals (Sweden)

    Karp Peter D

    2006-01-01

    Full Text Available Abstract Background Escherichia coli is the model organism for which our knowledge of its regulatory network is the most extensive. Over the last few years, our project has been collecting and curating the literature concerning E. coli transcription initiation and operons, providing in both the RegulonDB and EcoCyc databases the largest electronically encoded network available. A paper published recently by Ma et al. (2004 showed several differences in the versions of the network present in these two databases. Discrepancies have been corrected, annotations from this and other groups (Shen-Orr et al., 2002 have been added, making the RegulonDB and EcoCyc databases the largest comprehensive and constantly curated regulatory network of E. coli K-12. Results Several groups have been using these curated data as part of their bioinformatics and systems biology projects, in combination with external data obtained from other sources, thus enlarging the dataset initially obtained from either RegulonDB or EcoCyc of the E. coli K12 regulatory network. We kindly obtained from the groups of Uri Alon and Hong-Wu Ma the interactions they have added to enrich their public versions of the E. coli regulatory network. These were used to search for original references and curate them with the same standards we use regularly, adding in several cases the original references (instead of reviews or missing references, as well as adding the corresponding experimental evidence codes. We also corrected all discrepancies in the two databases available as explained below. Conclusion One hundred and fifty new interactions have been added to our databases as a result of this specific curation effort, in addition to those added as a result of our continuous curation work. RegulonDB gene names are now based on those of EcoCyc to avoid confusion due to gene names and synonyms, and the public releases of RegulonDB and EcoCyc are henceforth synchronized to avoid confusion due to

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

    Science.gov (United States)

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

    2013-06-07

    Genome-scale network reconstruction has enabled predictive modeling of metabolism for many systems. Traditionally, protein structural information has not been represented in such reconstructions. Expansion of 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. This analysis allowed the prediction of protein activities that limit network function at superoptimal temperatures and mechanistic interpretations of mutations found in strains adapted to heat. Predicted growth-limiting factors for thermotolerance were validated through nutrient supplementation experiments and defined metabolic sensitivities to heat stress, providing evidence that metabolic enzyme thermostability is rate-limiting at superoptimal temperatures. Inclusion of structural information expanded the content and predictive capability of genome-scale metabolic networks that enable structural systems biology of metabolism.

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

    DEFF Research Database (Denmark)

    Agger, Morten; Scheutz, Flemming; Villumsen, Steen

    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...... associated with antibiotic treatment during acute VTEC infection and in chronic VTEC carrier states. METHODS: A systematic search in PubMed identified 1 meta-analysis, 10 clinical studies and 22 in vitro/in vivo studies. RESULTS: Four clinical studies found an increased risk of HUS, four studies found...... no altered risk of HUS and two studies found a protective effect of antibiotics. In vitro and clinical studies suggest that DNA synthesis inhibitors should be avoided, whereas evidence from in vitro studies indicates that certain protein and cell wall synthesis inhibitors reduce the release of toxins from...

  11. Purine Biosynthesis Metabolically Constrains Intracellular Survival of Uropathogenic Escherichia coli

    Science.gov (United States)

    Shaffer, Carrie L.; Zhang, Ellisa W.; Dudley, Anne G.; Dixon, Beverly R. E. A.; Guckes, Kirsten R.; Breland, Erin J.; Floyd, Kyle A.; Casella, Daniel P.; Algood, Holly M. Scott; Clayton, Douglass B.

    2016-01-01

    ABSTRACT The ability to de novo synthesize purines has been associated with the intracellular survival of multiple bacterial pathogens. Uropathogenic Escherichia coli (UPEC), the predominant cause of urinary tract infections, undergoes a transient intracellular lifestyle during which bacteria clonally expand into multicellular bacterial communities within the cytoplasm of bladder epithelial cells. Here, we characterized the contribution of the conserved de novo purine biosynthesis-associated locus cvpA-purF to UPEC pathogenesis. Deletion of cvpA-purF, or of purF alone, abolished de novo purine biosynthesis but did not impact bacterial adherence properties in vitro or in the bladder lumen. However, upon internalization by bladder epithelial cells, UPEC deficient in de novo purine biosynthesis was unable to expand into intracytoplasmic bacterial communities over time, unless it was extrachromosomally complemented. These findings indicate that UPEC is deprived of purine nucleotides within the intracellular niche and relies on de novo purine synthesis to meet this metabolic requirement. PMID:27795353

  12. Enterotoxigenic Escherichia coli infection induces intestinal epithelial cell autophagy.

    Science.gov (United States)

    Tang, Yulong; Li, Fengna; Tan, Bie; Liu, Gang; Kong, Xiangfeng; Hardwidge, Philip R; Yin, Yulong

    2014-06-25

    The morbidity and mortality in piglets caused by enterotoxigenic Escherichia coli (ETEC) results in large economic losses to the swine industry, but the precise pathogenesis of ETEC-associated diseases remains unknown. Intestinal epithelial cell autophagy serves as a host defense against pathogens. We found that ETEC induced autophagy, as measured by both the increased punctae distribution of GFP-LC3 and the enhanced conversion of LC3-I to LC3-II. Inhibiting autophagy resulted in decreased survival of IPEC-1 cells infected with ETEC. ETEC triggered autophagy in IPEC-1 cells through a pathway involving the mammalian target of rapamycin (mTOR), the extracellular signal-regulated kinases 1/2 (ERK1/2), and the AMP-activated protein kinase (AMPK). Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Antibacterial Coating for Elimination of Pseudomonas aeruginosa and Escherichia coli

    Directory of Open Access Journals (Sweden)

    Zainal Abidin Ali

    2014-01-01

    Full Text Available A polymer antibacterial surface has been successfully developed. The coating system used silane as binder and Ag particles as antibacterial agent. The silver was synthesized using precipitation method. X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, Brunauer-Emmett-Teller (BET tests, energy-dispersive X-ray spectroscopy (EDX, and X-ray photoelectron spectroscopy (XPS were carried out to evaluate the silver particles. Antibacterial properties of the coating system were tested against gram-negative bacteria, namely, Pseudomonas aeruginosa and Escherichia coli. Different amounts of Ag were used in the coating to optimize its usage. The Japanese International Standard, JISZ2801, was used for bacteria test and the surface developed complies with the standard being antibacterial.

  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. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Characterization of bioreaction processes: aerobic Escherichia coli cultures.

    Science.gov (United States)

    Guardia Alba, M J; García Calvo, E

    2001-11-30

    The simulation of a microbial transformation course is an important tool for the optimal design or characterization of industrial processes. Usually, models are developed to describe a specific part of the culture such as microbial growth and most of the time ignore the influence of physical and chemical environment on growth dynamics of the microorganism. In this work we propose a method which combines the description of the evolution of components involved in the bioprocess including biomass and the physical environment generated mainly by the bioreactor characteristics and operational conditions. Stoichiometric, kinetic, fluid dynamics and mass transfer models are linked to predict the course of the Escherichia coli culture under the influence of different experimental conditions and types of bioreactors. A set of 22 kinetic and physical parameters obtained from independent experiments and from literature are used in order to predict glucose, biomass, acetate, dissolved oxygen and CO(2) concentrations in airlift and stirred tank bioreactors.

  16. Increasing the permeability of Escherichia coli using MAC13243

    DEFF Research Database (Denmark)

    Muheim, Claudio; Götzke, Hansjörg; Eriksson, Anna U.

    2017-01-01

    The outer membrane of gram-negative bacteria is a permeability barrier that prevents the efficient uptake of molecules with large scaffolds. As a consequence, a number of antibiotic classes are ineffective against gram-negative strains. Herein we carried out a high throughput screen for small mol...... molecules that make the outer membrane of Escherichia coli more permeable. We identified MAC13243, an inhibitor of the periplasmic chaperone LolA that traffics lipoproteins from the inner to the outer membrane. We observed that cells were (1) more permeable to the fluorescent probe 1-N......-phenylnapthylamine, and (2) more susceptible to large-scaffold antibiotics when sub-inhibitory concentrations of MAC13243 were used. To exclude the possibility that the permeability was caused by an off-target effect, we genetically reconstructed the MAC13243-phenotype by depleting LolA levels using the CRISPRi system....

  17. Structure of the Cyclomodulin Cif from Pathogenic Escherichia coli

    Science.gov (United States)

    Hsu, Yun; Jubelin, Gregory; Taieb, Frédéric; Nougayrède, Jean-Philippe; Oswald, Eric; Stebbins, C. Erec

    2009-01-01

    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. PMID:18845161

  18. Sickness behavior in dairy cows during Escherichia coli mastitis

    DEFF Research Database (Denmark)

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

    2012-01-01

    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....... This knowledge can be useful for the development of welfare assessment protocols, early disease detection, and for future work aimed at understanding the behavioral needs of dairy cows suffering from mastitis....

  19. Countermeasures to survive excessive chromosome replication in Escherichia coli

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Riber, Leise; Løbner-Olesen, Anders

    2018-01-01

    model where all mutations that suppress overinitiation keep replication forks separated in time and, thereby, reduce the formation of strand breaks. One group of mutations does so by lowering the activity of oriC and/or DnaA to reduce the frequency of initiations to an acceptable level. In the other...... group of mutations, replication forks are kept apart by preventing formation of damages that would otherwise cause replication blocks, by allowing bypass of replication blocks and/or by slowing down replication forks. This group of suppressors restores viability despite excessive chromosome replication......In Escherichia coli, like all organisms, DNA replication is coordinated with cell cycle progression to ensure duplication of the genome prior to cell division. Chromosome replication is initiated from the replication origin, oriC, by the DnaA protein associated with ATP. Initiations take place once...

  20. 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.

  1. 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.

  2. Parallel Mapping of Antibiotic Resistance Alleles in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Sophie J Weiss

    Full Text Available Chemical genomics expands our understanding of microbial tolerance to inhibitory chemicals, but its scope is often limited by the throughput of genome-scale library construction and genotype-phenotype mapping. Here we report a method for rapid, parallel, and deep characterization of the response to antibiotics in Escherichia coli using a barcoded genome-scale library, next-generation sequencing, and streamlined bioinformatics software. The method provides quantitative growth data (over 200,000 measurements and identifies contributing antimicrobial resistance and susceptibility alleles. Using multivariate analysis, we also find that subtle differences in the population responses resonate across multiple levels of functional hierarchy. Finally, we use machine learning to identify a unique allelic and proteomic fingerprint for each antibiotic. The method can be broadly applied to tolerance for any chemical from toxic metabolites to next-generation biofuels and antibiotics.

  3. Parallel Mapping of Antibiotic Resistance Alleles in Escherichia coli.

    Science.gov (United States)

    Weiss, Sophie J; Mansell, Thomas J; Mortazavi, Pooneh; Knight, Rob; Gill, Ryan T

    2016-01-01

    Chemical genomics expands our understanding of microbial tolerance to inhibitory chemicals, but its scope is often limited by the throughput of genome-scale library construction and genotype-phenotype mapping. Here we report a method for rapid, parallel, and deep characterization of the response to antibiotics in Escherichia coli using a barcoded genome-scale library, next-generation sequencing, and streamlined bioinformatics software. The method provides quantitative growth data (over 200,000 measurements) and identifies contributing antimicrobial resistance and susceptibility alleles. Using multivariate analysis, we also find that subtle differences in the population responses resonate across multiple levels of functional hierarchy. Finally, we use machine learning to identify a unique allelic and proteomic fingerprint for each antibiotic. The method can be broadly applied to tolerance for any chemical from toxic metabolites to next-generation biofuels and antibiotics.

  4. Structure of the cyclomodulin Cif from pathogenic Escherichia coli.

    Science.gov (United States)

    Hsu, Yun; Jubelin, Gregory; Taieb, Frédéric; Nougayrède, Jean-Philippe; Oswald, Eric; Stebbins, C Erec

    2008-12-12

    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.

  5. 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.

  6. Transport of Escherichia coli phage through saturated porous media considering managed aquifer recharge.

    Science.gov (United States)

    Zhang, Wenjing; Li, Shuo; Wang, Shuang; Lei, Liancheng; Yu, Xipeng; Ma, Tianyi

    2017-12-18

    Virus is one of the most potentially harmful microorganisms in groundwater. In this paper, the effects of hydrodynamic and hydrogeochemical conditions on the transportation of the colloidal virus considering managed aquifer recharge were systematically investigated. Escherichia coli phage, vB_EcoM-ep3, has a broad host range and was able to lyse pathogenic Escherichia coli. Bacteriophage with low risk to infect human has been found extensively in the groundwater environment, so it is considered as a representative model of groundwater viruses. Laboratory studies were carried out to analyze the transport of the Escherichia coli phage under varying conditions of pH, ionic strength, cation valence, flow rate, porous media, and phosphate buffer concentration. The results indicated that decreasing the pH will increase the adsorption of Escherichia coli phage. Increasing the ionic strength, either Na + or Ca 2+ , will form negative condition for the migration of Escherichia coli phage. A comparison of different cation valence tests indicated that changes in transport and deposition were more pronounced with divalent Ca 2+ than monovalent Na + . As the flow rate increases, the release of Escherichia coli phage increases and the retention of Escherichia coli phage in the aquifer medium reduces. Changes in porous media had a significant effect on Escherichia coli phage migration. With increase of phosphate buffer concentration, the suspension stability and migration ability of Escherichia coli phage are both increased. Based on laboratory-scale column experiments, a one-dimensional transport model was established to quantitatively describe the virus transport in saturated porous medium.

  7. High-yield recombinant expression of the chicken antimicrobial peptide fowlicidin-2 in Escherichia coli.

    Science.gov (United States)

    Feng, Xingjun; Xu, Wenshan; Qu, Pei; Li, Xiaochong; Xing, Liwei; Liu, Di; Jiao, Jian; Wang, Jue; Li, Zhongqiu; Liu, Chunlong

    2015-01-01

    The antimicrobial peptide fowlicidin-2 identified in chicken is a member of the cathelicidins family. The mature fowlicidin-2 possesses high antibacterial efficacy and lipopolysaccharide (LPS) neutralizing activity, and also represents an excellent candidate as an antimicrobial agent. In the present study, the recombinant fowlicidin-2 was successfully produced by Escherichia coli (E. coli) recombinant expression system. The gene encoding fowlicidin-2 with the codon preference of E. coli was designed through codon optimization and synthesized in vitro. The gene was then ligated into the plasmid pET-32a(+), which features fusion protein thioredoxin at the N-terminal. The recombinant plasmid was transformed into E. coli BL21(DE3) and cultured in Luria-Bertani (LB) medium. After isopropyl-β-D-thiogalactopyranoside (IPTG) induction, the fowlicidin-2 fusion protein was successfully expressed as inclusion bodies. The inclusion bodies were dissolved and successfully released the peptide in 70% formic acid solution containing cyanogen bromide (CNBr) in a single step. After purification by reverse-phase high-performance liquid chromatography (RP-HPLC), ∼6.0 mg of fowlicidin-2 with purity more than 97% was obtained from 1 litre of bacteria culture. The recombinant peptide exhibited high antibacterial activity against the Gram-positive and Gram-negative bacteria, and even drug-resistant strains. This system could be used to rapidly and efficiently produce milligram quantities of a battery of recombinant antimicrobial peptides as well as for large-scale production. © 2015 American Institute of Chemical Engineers.

  8. Trade-Offs of Escherichia coli Adaptation to an Intracellular Lifestyle in Macrophages.

    Directory of Open Access Journals (Sweden)

    M Azevedo

    Full Text Available The bacterium Escherichia coli exhibits remarkable genomic and phenotypic variation, with some pathogenic strains having evolved to survive and even replicate in the harsh intra-macrophage environment. The rate and effects of mutations that can cause pathoadaptation are key determinants of the pace at which E. coli can colonize such niches and become pathogenic. We used experimental evolution to determine the speed and evolutionary paths undertaken by a commensal strain of E. coli when adapting to intracellular life. We estimated the acquisition of pathoadaptive mutations at a rate of 10-6 per genome per generation, resulting in the fixation of more virulent strains in less than a hundred generations. Whole genome sequencing of independently evolved clones showed that the main targets of intracellular adaptation involved loss of function mutations in genes implicated in the assembly of the lipopolysaccharide core, iron metabolism and di- and tri-peptide transport, namely rfaI, fhuA and tppB, respectively. We found a substantial amount of antagonistic pleiotropy in evolved populations, as well as metabolic trade-offs, commonly found in intracellular bacteria with reduced genome sizes. Overall, the low levels of clonal interference detected indicate that the first steps of the transition of a commensal E. coli into intracellular pathogens are dominated by a few pathoadaptive mutations with very strong effects.

  9. [Virulence factors and pathophysiology of extraintestinal pathogenic Escherichia coli].

    Science.gov (United States)

    Bidet, P; Bonarcorsi, S; Bingen, E

    2012-11-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) causing urinary tract infections, bacteraemia or meningitis are characterized by a particular genetic background (phylogenetic group B2 and D) and the presence, within genetic pathogenicity islands (PAI) or plasmids, of genes encoding virulence factors involved in adhesion to epithelia, crossing of the body barriers (digestive, kidney, bloodbrain), iron uptake and resistance to the immune system. Among the many virulence factors described, two are particularly linked with a pathophysiological process: type P pili PapGII adhesin is linked with acute pyelonephritis, in the absence of abnormal flow of urine, and the K1 capsule is linked with neonatal meningitis. However, if the adhesin PapGII appears as the key factor of pyelonephritis, such that its absence in strain causing the infection is predictive of malformation or a vesico-ureteral reflux, the meningeal virulence of E. coli can not be reduced to a single virulence factor, but results from a combination of factors unique to each clone, and an imbalance between the immune defenses of the host and bacterial virulence. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  10. Bacteriophages with the Ability to Degrade Uropathogenic Escherichia Coli Biofilms

    Directory of Open Access Journals (Sweden)

    Amee Manges

    2012-04-01

    Full Text Available Escherichia coli-associated urinary tract infections (UTIs are among the most common bacterial infections in humans. UTIs are usually managed with antibiotic therapy, but over the years, antibiotic-resistant strains of uropathogenic E. coli (UPEC have emerged. The formation of biofilms further complicates the treatment of these infections by making them resistant to killing by the host immune system as well as by antibiotics. This has encouraged research into therapy using bacteriophages (phages as a supplement or substitute for antibiotics. In this study we characterized 253 UPEC in terms of their biofilm-forming capabilities, serotype, and antimicrobial resistance. Three phages were then isolated (vB_EcoP_ACG-C91, vB_EcoM_ACG-C40 and vB_EcoS_ACG-M12 which were able to lyse 80.5% of a subset (42 of the UPEC strains able to form biofilms. Correlation was established between phage sensitivity and specific serotypes of the UPEC strains. The phages’ genome sequences were determined and resulted in classification of vB_EcoP_ACG-C91 as a SP6likevirus, vB_EcoM_ACG-C40 as a T4likevirus and vB_EcoS_ACG-M12 as T1likevirus. We assessed the ability of the three phages to eradicate the established biofilm of one of the UPEC strains used in the study. All phages significantly reduced the biofilm within 2–12 h of incubation.

  11. mcr-1 identified in Avian Pathogenic Escherichia coli (APEC).

    Science.gov (United States)

    Lima Barbieri, Nicolle; Nielsen, Daniel W; Wannemuehler, Yvonne; Cavender, Tia; Hussein, Ashraf; Yan, Shi-Gan; Nolan, Lisa K; Logue, Catherine M

    2017-01-01

    Antimicrobial resistance associated with colistin has emerged as a significant concern worldwide threatening the use of one of the most important antimicrobials for treating human disease. Here, we examined a collection (n = 980) of Avian Pathogenic Escherichia coli (APEC) isolated from poultry with colibacillosis from the US and internationally for the presence of mcr-1 and mcr-2, genes known to encode colistin resistance. Included in the analysis was an additional set of avian fecal E. coli (AFEC) (n = 220) isolates from healthy birds for comparative analysis. The mcr-1 gene was detected in a total of 12 isolates recovered from diseased production birds from China and Egypt. No mcr genes were detected in the healthy fecal isolates. The full mcr-1 gene from positive isolates was sequenced using specifically designed primers and were compared with sequences currently described in NCBI. mcr-1 positive isolates were also assessed for phenotypic colistin resistance and extended spectrum beta lactam phenotypes and genotypes. This study has identified mcr-1 in APEC isolates dating back to at least 2010 and suggests that animal husbandry practices could result in a potential source of resistance to the human food chain in countries where application of colistin in animal health is practiced.

  12. Expression of recombinant alkaline phosphatase conjugates in Escherichia coli.

    Science.gov (United States)

    Boulain, Jean-Claude; Ducancel, Frédéric

    2004-01-01

    The methods described in this article are relative to the use of a positive cloning/screening recombinant system for the generation in Escherichia coli of foreign proteins fused to a highly active bacterial alkaline phosphatase (PhoA) variant as reporter enzyme. Appropriate insertion of the DNA encoding the foreign peptides, proteic domains, or proteins between codons +6 and +7 of the phoa gene restores the initial frame of the phoa gene in the vector. Consequently, only recombinant clones appear as blue colonies when plating onto an agar medium containing a chromogenic substrate for PhoA. The presence of an intact PhoA signal peptide yields to a systematic secretion of the fusion proteins into the periplasm where the PhoA dimerises to its active form, and disulfides can be formed if necessary. The resultant PhoA-tagged proteins are particularly convenient novel tools that can be used in a wide range of applications, including expression, epitope mapping, histochemistry, immunoblotting, mutant analysis, and competition or sandwich ELISAs. Expression of an scFv antibody fragment derived from an IgG2a/kappa immunoglobulin specific for curaremimetic toxins from snake (named M-alpha2-3), will be used to illustrate the methods utilized for its cloning, expression in E.coli, extraction, and functional characterization.

  13. 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.

  14. Simple method for purification of enterotoxigenic Escherichia coli fimbriae.

    Science.gov (United States)

    Curtis, Brittany; Grassel, Christen; Laufer, Rachel S; Sears, Khandra T; Pasetti, Marcela F; Barry, Eileen M; Simon, Raphael

    2016-03-01

    Enterotoxigenic Escherichia coli (ETEC) are endemic pathogens in the developing world. They frequently cause illness in travelers, and are among the most prevalent causes of diarrheal disease in children. Pathogenic ETEC strains employ fimbriae as adhesion factors to bind the luminal surface of the intestinal epithelium and establish infection. Accordingly, there is marked interest in immunoprophylactic strategies targeting fimbriae to protect against ETEC infections. Multiple strategies have been reported for purification of ETEC fimbriae, however none is ideal. Purification has typically involved the use of highly virulent wild-type strains. We report here a simple and improved method to purify ETEC fimbriae, which was applied to obtain two different Class 5 fimbriae types of clinical relevance (CFA/I and CS4) expressed recombinantly in E. coli production strains. Following removal from cells by shearing, fimbriae proteins were purified by orthogonal purification steps employing ultracentrifugation, precipitation, and ion-exchange membrane chromatography. Purified fimbriae demonstrated the anticipated size and morphology by electron microscopy analysis, contained negligible levels of residual host cell proteins, nucleic acid, and endotoxin, and were recognized by convalescent human anti-sera. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. 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.

  16. Dynamic organization of chromosomal DNA in Escherichia coli.

    Science.gov (United States)

    Niki, H; Yamaichi, Y; Hiraga, S

    2000-01-15

    We have revealed the subcellular localization of different DNA segments that are located at approximately 230-kb intervals on the Escherichia coli chromosome using fluorescence in situ hybridization (FISH). The series of chromosome segments is localized within the cell in the same order as the chromosome map. The large chromosome region including oriC shows similar localization patterns, which we call the Ori domain. In addition, the localization pattern of the large segment including dif is characteristic of the replication terminus region. The segment also shows similar localization patterns, which we call the Ter domain. In newborn cells, Ori and Ter domains of the chromosome are differentially localized near opposite cell poles. Subsequently, in the B period, the Ori domain moves toward mid-cell before the initiation of replication, and the Ter domain tends to relocate at mid-cell. An inversion mutant, in which the Ter domain is located close to oriC, shows abnormal subcellular localization of ori and dif segments, resulting in frequent production of anucleate cells. These studies thus suggest that the E. coli chromosome is organized to form a compacted ring structure with the Ori and Ter domains; these domains participate in the cell cycle-dependent localization of the chromosome.

  17. Rapidly directional biotransformation of tauroursodeoxycholic acid through engineered Escherichia coli.

    Science.gov (United States)

    Shi, Jie; Wang, Jie; Yu, Lu; Yang, Li; Zhao, Shujuan; Wang, Zhengtao

    2017-07-01

    Bear bile powder is a precious medicinal material. It is characterized by high content of tauroursodeoxycholic acid (TUDCA) at a ratio of 1.0-1.5 to taurochenodeoxycholic acid (TCDCA). Here, we reported the biotransformation of tauroursodeoxycholic acid (TUDCA) through Escherichia coli engineered with a two-step mimic biosynthetic pathway of TUDCA from taurochenodeoxycholic acid (TCDCA). Two 7α-hydroxysteroid dehydrogenase (7α-HSDH) and two 7β-hydroxysteroid dehydrogenase (7β-HSDH) genes (named as α 1 , α 2 , β 1 , and β 2 ) were selected and synthesized to create four pathway variants using ePathBrick. All could convert TCDCA to TUDCA and the one harboring α 1 and β 2 (pα 1 β 2 ) showed the strongest capability. Utilizing the oxidative and reductive properties of 7α- and 7β-HSDH, an ideal balance between TUDCA and TCDCA was established by optimizing the fermentation conditions. By applying the optimal condition, E. coli containing pα 1 β 2 (BL-pα 1 β 2 ) produced up to 1.61 ± 0.13 g/L of TUDCA from 3.23 g/L of TCDCA at a ratio of 1.3 to TCDCA. This study provides a potential approach for bear bile substitute production from cheap and readily available chicken bile.

  18. The Stress Response of Escherichia coli under Microgravity.

    Science.gov (United States)

    Lynch, S.; Matin, A.

    At the onset of adverse environmental conditions, bacteria induce a controlled stress response to enable survival. Escherichia coli induces stress-specific reactions in response to a variety of environmental strains. A family of proteins termed sigma (s) factors is pivotal to the regulation of stress responses in bacteria. In particular Sigma S (ss) regulates several stress responses in E. coli and serves as an important global stress regulatory protein. Under optimal growth conditions, levels of ss are maintained at low cellular concentrations primarily via a proteolytic regulatory mechanism. At the onset of stress, ss levels increase due to increased stability of the molecule, facilitating transcriptional initiation and up regulation of specific stress related proteins. Concentrations of ss can therefore be indicative of cellular stress levels. Recent work by Kendrick et al demonstrated that Salmonella species grown under conditions of simulated microgravity display increased virulence - a stress-related phenotype. Using E. coli as a model system we aim to investigate the stress response elicited by the organism under conditions of simulated microgravity (SMG). SMG is generated in specially constructed rotary cell culture systems termed HARVs (High Aspect Ratio Vessels- Synthecon Inc.). By rotating at constant velocity around a vertical axis an environment is produced in which the gravitational vectors are randomized over the surface of the cell, resulting in an overall-time-averaged gravitational vector of 10-2 x g (4). E. coli cultures grown in HARVs under conditions of normal gravity (NG) and SMG repeatedly display slower growth kinetics under SMG. Western analysis of cells at exponential and stationary phase of growth from both cultures reveal similar levels of ss exist in exponential phase under both SMG and NG conditions. However, during stationary phase, levels of ss are at least 2-fold higher under conditions of SMG as compared to NG. Translational fusion

  19. Metabolic engineering of Escherichia coli for biosynthesis of hyaluronic acid.

    Science.gov (United States)

    Yu, Huimin; Stephanopoulos, Gregory

    2008-01-01

    Engineering of hyaluronic acid (HA) biosynthetic pathway in recombinant Escherichia coli as production host is reported in this work. A hyaluronic acid synthase (HAS) gene, sphasA, from Sreptococcus pyogenes with the start codon gtg to atg mutant, was expressed in recombinant E. coli with or without the genes ugd, galF and glmU, which are analogs of hasB, hasC and hasD from Streptococcus, respectively, encoding UDP-glucose 6-dehygrogenase, Glucose-1-P uridyltransferase, and N-acetyl glucosamine uridyltransferase enzymes in the HA biosynthetic pathway. The single, double and triple organized artificial operons of sphasA, ugd, galF and glmU were designed and constructed using the inducible plasmid backbone of pMBAD. Only the triple expression recombinant, Top10/pMBAD-spABC, generated a relatively high titer of HA (approximately 48 mg/l at 48 h), indicating that both of the enzymes encoded by ugd and galF are essential for HA biosynthesis. A new gene of ssehasA with identical protein sequence of seHAS from Streptococcus equisimilis, was artificially synthesized after substituting all of the rare codons in the natural sehasA. The HA titer at 24 h flask culture increased to approximately 190 mg/l in sseAB and 160 mg/l in sseABC, respectively. Sorbitol could be used as another carbon source for HA accumulation, and the metabolic pathway for HA synthesis in a recombinant E. coli was presented. The concentration of Mg(2+) cofactor of HA synthase was optimized and a cell growth inhibition phenomenon was observed during HA accumulation. Molecular weight (MW) measurements revealed that the mean MW of HA produced from the recombinant E. coli under different conditions ranges from approximately 3.5x10(5) to 1.9x10(6)Da, indicating that the recombinant E. coli can be used as a potential host candidate for industrial production of HA.

  20. Risk of Transmission of Antimicrobial Resistant Escherichia coli from Commercial Broiler and Free-Range Retail Chicken in India

    Science.gov (United States)

    Hussain, Arif; Shaik, Sabiha; Ranjan, Amit; Nandanwar, Nishant; Tiwari, Sumeet K.; Majid, Mohammad; Baddam, Ramani; Qureshi, Insaf A.; Semmler, Torsten; Wieler, Lothar H.; Islam, Mohammad A.; Chakravortty, Dipshikha; Ahmed, Niyaz

    2017-01-01

    Multidrug-resistant Escherichia coli infections are a growing public health concern. This study analyzed the possibility of contamination of commercial poultry meat (broiler and free-range) with pathogenic and or multi-resistant E. coli in retail chain poultry meat markets in India. We analyzed 168 E. coli isolates from broiler and free-range retail poultry (meat/ceca) sampled over a wide geographical area, for their antimicrobial sensitivity, phylogenetic groupings, virulence determinants, extended-spectrum-β-lactamase (ESBL) genotypes, fingerprinting by Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR and genetic relatedness to human pathogenic E. coli using whole genome sequencing (WGS). The prevalence rates of ESBL producing E. coli among broiler chicken were: meat 46%; ceca 40%. Whereas, those for free range chicken were: meat 15%; ceca 30%. E. coli from broiler and free-range chicken exhibited varied prevalence rates for multi-drug resistance (meat 68%; ceca 64% and meat 8%; ceca 26%, respectively) and extraintestinal pathogenic E. coli (ExPEC) contamination (5 and 0%, respectively). WGS analysis confirmed two globally emergent human pathogenic lineages of E. coli, namely the ST131 (H30-Rx subclone) and ST117 among our poultry E. coli isolates. These results suggest that commercial poultry meat is not only an indirect public health risk by being a possible carrier of non-pathogenic multi-drug resistant (MDR)-E. coli, but could as well be the carrier of human E. coli pathotypes. Further, the free-range chicken appears to carry low risk of contamination with antimicrobial resistant and extraintestinal pathogenic E. coli (ExPEC). Overall, these observations reinforce the understanding that poultry meat in the retail chain could possibly be contaminated by MDR and/or pathogenic E. coli. PMID:29180984

  1. Risk of Transmission of Antimicrobial Resistant Escherichia coli from Commercial Broiler and Free-Range Retail Chicken in India.

    Science.gov (United States)

    Hussain, Arif; Shaik, Sabiha; Ranjan, Amit; Nandanwar, Nishant; Tiwari, Sumeet K; Majid, Mohammad; Baddam, Ramani; Qureshi, Insaf A; Semmler, Torsten; Wieler, Lothar H; Islam, Mohammad A; Chakravortty, Dipshikha; Ahmed, Niyaz

    2017-01-01

    Multidrug-resistant Escherichia coli infections are a growing public health concern. This study analyzed the possibility of contamination of commercial poultry meat (broiler and free-range) with pathogenic and or multi-resistant E. coli in retail chain poultry meat markets in India. We analyzed 168 E. coli isolates from broiler and free-range retail poultry (meat/ceca) sampled over a wide geographical area, for their antimicrobial sensitivity, phylogenetic groupings, virulence determinants, extended-spectrum-β-lactamase (ESBL) genotypes, fingerprinting by Enterobacterial Repetitive Intergenic Consensus (ERIC) PCR and genetic relatedness to human pathogenic E. coli using whole genome sequencing (WGS). The prevalence rates of ESBL producing E. coli among broiler chicken were: meat 46%; ceca 40%. Whereas, those for free range chicken were: meat 15%; ceca 30%. E. coli from broiler and free-range chicken exhibited varied prevalence rates for multi-drug resistance (meat 68%; ceca 64% and meat 8%; ceca 26%, respectively) and extraintestinal pathogenic E. coli (ExPEC) contamination (5 and 0%, respectively). WGS analysis confirmed two globally emergent human pathogenic lineages of E. coli, namely the ST131 (H30-Rx subclone) and ST117 among our poultry E. coli isolates. These results suggest that commercial poultry meat is not only an indirect public health risk by being a possible carrier of non-pathogenic multi-drug resistant (MDR)-E. coli, but could as well be the carrier of human E. coli pathotypes. Further, the free-range chicken appears to carry low risk of contamination with antimicrobial resistant and extraintestinal pathogenic E. coli (ExPEC). Overall, these observations reinforce the understanding that poultry meat in the retail chain could possibly be contaminated by MDR and/or pathogenic E. coli.

  2. Risk of Transmission of Antimicrobial Resistant Escherichia coli from Commercial Broiler and Free-Range Retail Chicken in India

    Directory of Open Access Journals (Sweden)

    Arif Hussain

    2017-11-01

    Full Text Available Multidrug-resistant Escherichia coli infections are a growing public health concern. This study analyzed the possibility of contamination of commercial poultry meat (broiler and free-range with pathogenic and or multi-resistant E. coli in retail chain poultry meat markets in India. We analyzed 168 E. coli isolates from broiler and free-range retail poultry (meat/ceca sampled over a wide geographical area, for their antimicrobial sensitivity, phylogenetic groupings, virulence determinants, extended-spectrum-β-lactamase (ESBL genotypes, fingerprinting by Enterobacterial Repetitive Intergenic Consensus (ERIC PCR and genetic relatedness to human pathogenic E. coli using whole genome sequencing (WGS. The prevalence rates of ESBL producing E. coli among broiler chicken were: meat 46%; ceca 40%. Whereas, those for free range chicken were: meat 15%; ceca 30%. E. coli from broiler and free-range chicken exhibited varied prevalence rates for multi-drug resistance (meat 68%; ceca 64% and meat 8%; ceca 26%, respectively and extraintestinal pathogenic E. coli (ExPEC contamination (5 and 0%, respectively. WGS analysis confirmed two globally emergent human pathogenic lineages of E. coli, namely the ST131 (H30-Rx subclone and ST117 among our poultry E. coli isolates. These results suggest that commercial poultry meat is not only an indirect public health risk by being a possible carrier of non-pathogenic multi-drug resistant (MDR-E. coli, but could as well be the carrier of human E. coli pathotypes. Further, the free-range chicken appears to carry low risk of contamination with antimicrobial resistant and extraintestinal pathogenic E. coli (ExPEC. Overall, these observations reinforce the understanding that poultry meat in the retail chain could possibly be contaminated by MDR and/or pathogenic E. coli.

  3. Extraintestinal pathogenic Escherichia coli are associated with intestinal inflammation in patients with ulcerative colitis

    DEFF Research Database (Denmark)

    Mirsepasi-Lauridsen, Hengameh C.; Halkjaer, Sofie Ingdam; Mortensen, Esben Munk

    2016-01-01

    E. coli of the phylogenetic group B2 harbouring Extra intestinal Pathogenic Escherichia coli (ExPEC) genes are frequently seen as colonizers of the intestine in patients with active ulcerative colitis (UC). In this study, we describe the influence of E. coli Nissle (EcN) B2 as add-on treatment to...... scores in comparison to patients colonized with E. coli A and D (p inflammation....

  4. Detection of Escherichia coli O157 and non-O157 Serogroups in ...

    African Journals Online (AJOL)

    Of the 21 (5.5%) diarrhoeagenic Escherichia coli strains recovered E. coli O157 accounted for 5 (1.3%), 6 (1.6%) and 9 (2.4%) respectively. The rate of isolation of E. coli O157 in cattle faeces and raw cow milk was 1.5% each while, water was 6.3%. The frequency of isolation of E. coli O118, O111 and O26 serotypes from ...

  5. An Unusual Case of Early Onset Persistent Escherichia coli Septicemia Associated with Endocarditis

    Directory of Open Access Journals (Sweden)

    Sachin K. Gupta

    2013-10-01

    Full Text Available Escherichia coli infection is very common cause of early onset septicemia especially in very low-birth-weight newborns, but E. coli endocarditis has not been described in newborns. E. coli endocarditis, even in the adult population, is a rare and not well-characterized disease and is associated with high mortality. We report a very unusual presentation of persistent E. coli infection associated with endocarditis.

  6. An Unusual Case of Early Onset Persistent Escherichia coli Septicemia Associated with Endocarditis

    OpenAIRE

    Gupta, Sachin K.; Nanda, Vishakha; Malviya, Prashant; Jacobs, Norman; Naheed, Z.; Joseph, Tessy

    2013-01-01

    Escherichia coli infection is very common cause of early onset septicemia especially in very low-birth-weight newborns, but E. coli endocarditis has not been described in newborns. E. coli endocarditis, even in the adult population, is a rare and not well-characterized disease and is associated with high mortality. We report a very unusual presentation of persistent E. coli infection associated with endocarditis.

  7. Precise determinations of C and D periods by flow cytometry in Escherichia coli K-12 and B/r

    DEFF Research Database (Denmark)

    Michelsen, Ole; de Mattos, M.J.T.; Jensen, Peter Ruhdal

    2003-01-01

    The C and D cell cycle periods of seven Escherichia coli K-12 strains and three E, coli B/r strains were determined by computer simulation of DNA histograms obtained by flow cytometry of batch cultures grown at several different generation times. To obtain longer generation times two of the K-12...... generation times. In glucose-limited chemostats good correlation was found between D periods and generation times, whereas batch cultures exhibited carbon-source-dependent variations. Chemostat cultures showed cell cycle variations very similar to those obtained in batch cultures. These flow cytometric...

  8. Proteome reallocation in Escherichia coli with increasing specific growth rate.

    Science.gov (United States)

    Peebo, Karl; Valgepea, Kaspar; Maser, Andres; Nahku, Ranno; Adamberg, Kaarel; Vilu, Raivo

    2015-04-01

    Cells usually respond to changing growth conditions with a change in the specific growth rate (μ) and adjustment of their proteome to adapt and maintain metabolic efficiency. Description of the principles behind proteome resource allocation is important for understanding metabolic regulation in response to changing μ. Thus, we analysed the proteome resource allocation dynamics of Escherichia coli into different metabolic processes in response to changing μ. E. coli was grown on minimal and defined rich media in steady state continuous cultures at different μ and characterised combining two LC-MS/MS-based proteomics methods: stable isotope labelling by amino acids in cell culture (SILAC) and intensity based label-free absolute quantification. We detected slowly growing cells investing more proteome resources in energy generation and carbohydrate transport and metabolism whereas for achieving faster growth cells needed to devote most resources to translation and processes closely related to the protein synthesis pipeline. Furthermore, down-regulation of energy generation and carbohydrate metabolism proteins with faster growth displayed very similar expression dynamics with the global transcriptional regulator CRP (cyclic AMP receptor protein), pointing to a dominant protein resource allocating role of this protein. Our data also suggest that acetate overflow may be the result of global proteome resource optimisation as cells saved proteome resources by switching from fully respiratory to respiro-fermentative growth. The presented results give a quantitative overview of how E. coli adjusts its proteome to achieve faster growth and in future could contribute to the design of more efficient cell factories through proteome optimisation.

  9. WGS accurately predicts antimicrobial resistance in Escherichia coli.

    Science.gov (United States)

    Tyson, Gregory H; McDermott, Patrick F; Li, Cong; Chen, Yuansha; Tadesse, Daniel A; Mukherjee, Sampa; Bodeis-Jones, Sonya; Kabera, Claudine; Gaines, Stuart A; Loneragan, Guy H; Edrington, Tom S; Torrence, Mary; Harhay, Dayna M; Zhao, Shaohua

    2015-10-01

    The objective of this study was to determine the effectiveness of WGS in identifying resistance genotypes of MDR Escherichia coli and whether these correlate with observed phenotypes. Seventy-six E. coli strains were isolated from farm cattle and measured for phenotypic resistance to 15 antimicrobials with the Sensititre(®) system. Isolates with resistance to at least four antimicrobials in three classes were selected for WGS using an Illumina MiSeq. Genotypic analysis was conducted with in-house Perl scripts using BLAST analysis to identify known genes and mutations associated with clinical resistance. Over 30 resistance genes and a number of resistance mutations were identified among the E. coli isolates. Resistance genotypes correlated with 97.8% specificity and 99.6% sensitivity to the identified phenotypes. The majority of discordant results were attributable to the aminoglycoside streptomycin, whereas there was a perfect genotype-phenotype correlation for most antibiotic classes such as tetracyclines, quinolones and phenicols. WGS also revealed information about rare resistance mechanisms, such as structural mutations in chromosomal copies of ampC conferring third-generation cephalosporin resistance. WGS can provide comprehensive resistance genotypes and is capable of accurately predicting resistance phenotypes, making it a valuable tool for surveillance. Moreover, the data presented here showing the ability to accurately predict resistance suggest that WGS may be used as a screening tool in selecting anti-infective therapy, especially as costs drop and methods improve. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  10. Binding of collagens to an enterotoxigenic strain of Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Visai, L.; Speziale, P.; Bozzini, S. (Univ. of Pavia (Italy))

    1990-02-01

    An enterotoxigenic strain of Escherichia coli, B34289c, has been shown to bind the N-terminal region of fibronectin with high affinity. We now report that this strain also binds collagen. The binding of 125I-labeled type II collagen to bacteria was time dependent and reversible. Bacteria expressed a limited number of collagen receptors (2.2 x 10(4) per cell) and bound collagen with a Kd of 20 nM. All collagen types tested (I to V) as well as all tested cyanogen bromide-generated peptides (alpha 1(I)CB2, alpha 1(I)CB3, alpha 1(I)CB7, alpha 1(I)CB8, and alpha 2(I)CB4) were recognized by bacterial receptors, as demonstrated by the ability of these proteins to inhibit the binding of 125I-labeled collagen to bacteria. Of several unlabeled proteins tested in competition experiments, fibronectin and its N-terminal region strongly inhibited binding of the radiolabeled collagen to E. coli cells. Conversely, collagen competed with an 125I-labeled 28-kilodalton fibronectin fragment for bacterial binding. Collagen bound to bacteria could be displaced by excess amounts of either unlabeled fibronectin or its N-terminal fragment. Similarly, collagen could displace 125I-labeled N-terminal peptide of fibronectin bound to the bacterial cell surface. Bacteria grown at 41 degrees C or in the presence of glucose did not express collagen or fibronectin receptors. These results indicate the presence of specific binding sites for collagen on the surface of E. coli cells and furthermore that the collagen and fibronectin binding sites are located in close proximity, possibly on the same structure.

  11. Recombinational construction in Escherichia coli of infectious adenoviral genomes

    Science.gov (United States)

    Crouzet, Joël; Naudin, Laurent; Orsini, Cécile; Vigne, Emmanuelle; Ferrero, Lucy; Le Roux, Aude; Benoit, Patrick; Latta, Martine; Torrent, Christophe; Branellec, Didier; Denèfle, Patrice; Mayaux, Jean-François; Perricaudet, Michel; Yeh, Patrice

    1997-01-01

    A two-step gene replacement procedure was developed that generates infectious adenoviral genomes through homologous recombination in Escherichia coli. As a prerequisite, a human adenovirus serotype 5 (Ad5)-derived genome was first introduced as a PacI restriction fragment into an incP-derived replicon which, in contrast to ColE1-derivatives (e.g., pBR322 or pUC plasmids), is functional in a polA mutant of E. coli. Any modification can be introduced at will following two consecutive homologous recombinations between the incP/Ad5 replicon and the ColE1 plasmid. The overall procedure requires only the in vitro engineering of the ColE1-derivative by flanking the desired modification with small stretches of identical sequences. In the first step, a cointegrate between the tetracycline-resistant incP/Ad5 replicon and the kanamycin-resistant ColE1-derivative is selected by growing the polA host in the presence of both antibiotics. Resolution of this cointegrate is further selected in sucrose growth conditions due to the loss of a conditional suicide marker (the sacB gene of Bacillus subtilis) present in the ColE1 plasmid, leading to unmodified and modified incP/Ad5 replicons that can be differentiated upon restriction analysis. Consecutive rounds of this two-step cloning procedure allowed the introduction of multiple independent modifications within the virus genome, with no requirement for an intermediate virus. The potential of this procedure is demonstrated by the recovery of several E1E3E4-deleted adenoviruses following transfection of the corresponding E. coli-derived genomes in IGRP2 cells. PMID:9037067

  12. Tetracycline rapidly reaches all the constituent cells of uropathogenic Escherichia coli biofilms

    Science.gov (United States)

    Stone, G.; Wood, P.; Dixon, L.; Keyhan, M.; Matin, A.; Demain, A. L. (Principal Investigator)

    2002-01-01

    We have developed a method for visualizing Escherichia coli cells that are exposed to tetracycline in a biofilm, based on a previous report that liposomes containing the E. coli TetR(B) protein fluoresce when exposed to this antibiotic. By our method, cells devoid of TetR(B) also exhibited tetracycline-dependent fluorescence. At 50 microg of tetracycline ml(-1), planktonic cells of a uropathogenic E. coli (UPEC) strain developed maximal fluorescence after 7.5 to 10 min of exposure. A similar behavior was exhibited by cells in a 24- or 48-h UPEC biofilm, as examined by confocal laser microscopy, regardless of whether they lined empty spaces or occupied densely packed regions. Further, a comparison of phase-contrast and fluorescent images of corresponding biofilm zones showed that all the cells fluoresced. Thus, all the biofilm cells were exposed to tetracycline and there were no pockets within the biofilm where the antibiotic failed to reach. It also appeared unlikely that niches of reduced exposure to the antibiotic existed within the biofilms.

  13. Toxicity evaluation of CdTe quantum dots with different size on Escherichia coli.

    Science.gov (United States)

    Fang, Ting-Ting; Li, Xi; Wang, Qi-Sui; Zhang, Zhi-Jun; Liu, Peng; Zhang, Chao-Can

    2012-10-01

    Quantum dots (QDs) have a great potential for applications in nanomedicine. However, a few studies showed that they also exhibited toxicity. We used Escherichia coli (E. coli) as the model to study the effect of CdTe QDs on the cell growth by microcalorimetric technique, optical density (OD(600)) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra. Three size aqueous-compatible CdTe QDs with maximum emission of 543 nm (green-emitting QDs, GQDs), 579 nm (yellow-emitting QDs, YQDs) and 647 nm (red-emitting QDs, RQDs) were tested. The growth rate constants (k) and half-inhibiting concentration (IC(50)) were calculated from the microcalorimetric data. The results indicated that CdTe QDs exhibited a dose-dependent inhibitory effect on cell growth. The order of toxicity is GQDs>YQDs>RQDs. The smaller the particle size of QDs is, the more toxicity it is. ATR-FTIR spectra indicated that the outer membrane of the cell was changed or damaged by the QDs, which may induce QDs and harmful by-products to enter into the cells. These could be one of the reasons that CdTe QDs have cytotoxic effects on E. coli. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. L-Tryptophan Production in Escherichia coli Improved by Weakening the Pta-AckA Pathway.

    Science.gov (United States)

    Liu, Lina; Duan, Xuguo; Wu, Jing

    2016-01-01

    Acetate accumulation during the fermentation process of Escherichia coli FB-04, an L-tryptophan production strain, is detrimental to L-tryptophan production. In an initial attempt to reduce acetate formation, the phosphate acetyltransferase gene (pta) from E. coli FB-04 was deleted, forming strain FB-04(Δpta). Unfortunately, FB-04(Δpta) exhibited a growth defect. Therefore, pta was replaced with a pta variant (pta1) from E. coli CCTCC M 2016009, forming strain FB-04(pta1). Pta1 exhibits lower catalytic capacity and substrate affinity than Pta because of a single amino acid substitution (Pro69Leu). FB-04(pta1) lacked the growth defect of FB-04(Δpta) and showed improved fermentation performance. Strain FB-04(pta1) showed a 91% increase in L-tryptophan yield in flask fermentation experiments, while acetate production decreased by 35%, compared with its parent FB-04. Throughout the fed-batch fermentation process, acetate accumulation by FB-04(pta1) was slower than that by FB-04. The final L-tryptophan titer of FB-04(pta1) reached 44.0 g/L, representing a 15% increase over that of FB-04. Metabolomics analysis showed that the pta1 genomic substitution slightly decreased carbon flux through glycolysis and significantly increased carbon fluxes through the pentose phosphate and common aromatic pathways. These results indicate that this strategy enhances L-tryptophan production and decreases acetate accumulation during the L-tryptophan fermentation process.

  15. Escherichia coli bacteriocins: antimicrobial efficacy and prevalence among isolates from patients with bacteraemia.

    Directory of Open Access Journals (Sweden)

    Maruška Budič

    Full Text Available Bacteriocins are antimicrobial peptides generally active against bacteria closely related to the producer. Escherichia coli produces two types of bacteriocins, colicins and microcins. The in vitro efficacy of isolated colicins E1, E6, E7, K and M, was assessed against Escherichia coli strains from patients with bacteraemia of urinary tract origin. Colicin E7 was most effective, as only 13% of the tested strains were resistant. On the other hand, 32%, 33%, 43% and 53% of the tested strains exhibited resistance to colicins E6, K, M and E1. Moreover, the inhibitory activity of individual colicins E1, E6, E7, K and M and combinations of colicins K, M, E7 and E1, E6, E7, K, M were followed in liquid broth for 24 hours. Resistance against individual colicins developed after 9 hours of treatment. On the contrary, resistance development against the combined action of 5 colicins was not observed. One hundred and five E. coli strains from patients with bacteraemia were screened by PCR for the presence of 5 colicins and 7 microcins. Sixty-six percent of the strains encoded at least one bacteriocin, 43% one or more colicins, and 54% one or more microcins. Microcins were found to co-occur with toxins, siderophores, adhesins and with the Toll/Interleukin-1 receptor domain-containing protein involved in suppression of innate immunity, and were significantly more prevalent among strains from non-immunocompromised patients. In addition, microcins were highly prevalent among non-multidrug-resistant strains compared to multidrug-resistant strains. Our results indicate that microcins contribute to virulence of E. coli instigating bacteraemia of urinary tract origin.

  16. Recombinant OmpA protein fragments mediate interleukin-17 regulation to prevent Escherichia coli meningitis.

    Science.gov (United States)

    Hsieh, Wen-Shyang; Yang, Yi-Yuan; Lin, Pei-Hsuan; Chang, Chia-Chih; Wu, Hsueh-Hsia

    2016-12-01

    Neonates are at a higher risk for bacterial meningitis than children of other age groups. Although the mortality rates have decreased over the past few decades, neonatal meningitis is still a severe disease with high morbidity. For bacterial meningitis, antibiotic therapy is the primary choice for management. However, neurologic complications often cannot be averted; ∼40% of survivors exhibit neurological sequelae. Escherichia coli infection is the common cause of neonatal meningitis. Previously, we have demonstrated that the recombinant loop 1-3, loop 2-3, and loop 2-4 fragments of OmpA protein can protect mice from death after intracerebral E. coli infection. In this study, the protective effects of the recombinant OmpA protein fragments in E. coli intracerebral infections were investigated. The effects of E. coli intracerebral infection on cytokine and chemokine expression were determined. We also used various recombinant fragments of the OmpA protein to investigate the effects of these recombinant OmpA protein fragments on cytokine and chemokine expression. In this study, we demonstrated that the expression of interleukin-17 and other cytokines, chemokines, inducible nitric oxide synthase, and cyclooxygenase-2 are involved in the inflammatory processes of intracerebral E. coli infection. We also demonstrated that specific recombinant OmpA protein fragments (L1-3, L2-3, L2-4, and L3) can regulate cytokine, chemokine, nitric oxide synthase, and cyclooxygenase-2 expression and, subsequently, protect mice from death caused by intracerebral infection of E. coli. This finding indicates the potential for developing a new therapeutic approach to improve the prognosis of bacterial meningitis. Copyright © 2015. Published by Elsevier B.V.

  17. Recombinant outer membrane protein A fragments protect against Escherichia coli meningitis.

    Science.gov (United States)

    Hsieh, Wen-Shyang; Yang, Yi-Yuan; Yang, Hsin-Yi; Huang, Yu-Shan; Wu, Hsueh-Hsia

    2016-06-01

    Although the mortality rates have decreased over the past few decades, neonatal meningitis is still a severe disease with high morbidity. Moreover, approximately 40% of survivors exhibit neurological sequelae. Escherichia coli is the major Gram-negative bacterial pathogen in neonatal meningitis. The N-terminal β-barrel domain of the outer membrane protein A (OmpA) of E. coli is essential for effective protein conformation and function and contains four surface-exposed hydrophilic loops. In this study, we expressed different fragments of the four ring structures of the N-terminal domain, and investigated whether these recombinant OmpA fragments can protect mice from death after E. coli infection. We expressed the recombinant proteins of the following OmpA fragments by using molecular cloning of Loop 1-2, Loop 1-3, Loop 1-4, Loop 2-3, Loop 2-4, and Loop 3-4. Animal experiments were subsequently performed to investigate the effects of these recombinant OmpA fragments on the survival of C57BL/6 mice after intracerebral E. coli RS218 administration. This study demonstrated that the recombinant Loop 1-3, Loop 2-3, and Loop 2-4 fragments of OmpA can protect mice from intracerebral E. coli infection. In bacterial meningitis, although antibiotic therapy is the first choice for management, neurological complications can seldom be averted. Based on the results of the present study, we intend to establish an effective therapeutic application for E. coli meningitis. Copyright © 2014. Published by Elsevier B.V.

  18. Isolation, histopathology and antibiogram of Escherichia coli from pigeons (Columba livia

    Directory of Open Access Journals (Sweden)

    Pankaj Dutta

    2013-04-01

    Full Text Available Aim: To know the prevalence of antibiotic resistant Escherichia coli among dead and/or diarrhoic pigeons in and around greater Guwahati. Materials and Methods: Samples were cultured from dead and/or diarrhoic pigeons and identification was done by standard methods. The sensitivity of the isolated E.coli strains to 15 antibiotics of human and veterinary use was also determined. Organs from those dead birds from which E.coli were recovered were processed according to the routine procedure for histopathological studies. Results: Out of 150 pigeons subjected to microbiological investigation, 91(60.67 % samples were found positive for E. coli.The most frequently occurring serotypes were O157 (9.89%, followed by O68, O121 (7.69%, O9, O75, O131 (5.49%, O2, O13, O22 (3.30%. Antibiogram investigation of the isolates revealed that 91isolates (100% exhibited resistance against Ampicillin followed by Nitro-furantoin (73.62%, Tetracycline (65.93 %, Oxytetracycline (62.63 % and Streptomycin (61.54. Gross changes of some birds showed fibrinous pericarditis and perihepatitis and coligranuloma in different organs like liver and serosal surface of intestine. Microscopically, severe congestion and haemorrhages in different organs such as liver, kidney, lung and intestine. In some cases thick layer of fibrinous exudates with large number of heterophills over the surface of liver and heart with early degenerative changes as well as focal necrosis. Conclusion: The result of this study suggests that antimicrobial-resistant pathogenic E.coli is present in pigeons in and around greater Guwahati. Surveillance programs may be introduced to monitor antimicrobial resistance of pathogenic E.coli in pigeons in and around greater guwahati. [Vet World 2013; 6(2.000: 91-94

  19. Ribonuclease, deoxyribonuclease, and antiviral activity of Escherichia coli-expressed Bougainvillea xbuttiana antiviral protein 1.

    Science.gov (United States)

    Choudhary, N L; Yadav, O P; Lodha, M L

    2008-03-01

    A full-length cDNA encoding ribosome-inactivating/antiviral protein from the leaves of Bougainvillea xbuttiana was recently isolated. The coding region of cDNA was cloned and expressed in Escherichia coli, and the protein product was designated as BBAP1 (Bougainvillea xbuttiana antiviral protein 1). BBAP1 showed ribonuclease activity against Torula yeast RNA. It also exhibited depurination activity against supercoiled pBlueScript SK+ plasmid DNA in a concentration dependent manner, and was found to convert nicked circular DNA into linear form only at higher concentration. On bioassay, BBAP1 exhibited antiviral activity against sunnhemp rosette virus infecting Cyamopsis tetragonoloba leaves in which 95% inhibition of local lesion formation was observed.

  20. Antimicrobial Effect of Escherichia Coli on Essential Oils Derived from Romanian Aromatic Plants

    Directory of Open Access Journals (Sweden)

    Şandru Daniela Maria

    2015-07-01

    Full Text Available This paper investigates the antimicrobial action of Escherichia coli ATCCR CRM-8739TM on the following essential oils: Teucrium marum, Pinus sylwestris, Thymus vulgaris, Salviae aethedaroleum, Cinnamomum aromaticum, Hippophae rhamnoides, Lavandula angustifolia, Abies alba, Zingiber officinale, Anethum graveolens, Coriandrum sativum, Origanum vulgare, extracted industrialy from romanian plants, using the diffusion disc method. The most intense activity was observed at the essential oil of Cinnamomum aromaticum (cinnamon and the mildest activity was observed at Zingiber officinale (ginger. Many of the essential oils tested exhibited moderate antimicrobial activity, as Teucrium marum, Thymus vulgaris, Hippophae rhamnoides, Lavandula angustifolia,Coriandrum sativum. The lowest antibacterial activity was exhibited on Pinus sylwestris, Salviae aethedaroleum, Zingiber officinale and Anethum graveolens.