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  1. Transient infection of the zebrafish notochord with E. coli induces chronic inflammation

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    Mai Nguyen-Chi

    2014-07-01

    Full Text Available Zebrafish embryos and larvae are now well-established models in which to study infectious diseases. Infections with non-pathogenic Gram-negative Escherichia coli induce a strong and reproducible inflammatory response. Here, we study the cellular response of zebrafish larvae when E. coli bacteria are injected into the notochord and describe the effects. First, we provide direct evidence that the notochord is a unique organ that is inaccessible to leukocytes (macrophages and neutrophils during the early stages of inflammation. Second, we show that notochord infection induces a host response that is characterised by rapid clearance of the bacteria, strong leukocyte recruitment around the notochord and prolonged inflammation that lasts several days after bacteria clearance. During this inflammatory response, il1b is first expressed in macrophages and subsequently at high levels in neutrophils. Moreover, knock down of il1b alters the recruitment of neutrophils to the notochord, demonstrating the important role of this cytokine in the maintenance of inflammation in the notochord. Eventually, infection of the notochord induces severe defects of the notochord that correlate with neutrophil degranulation occurring around this tissue. This is the first in vivo evidence that neutrophils can degranulate in the absence of a direct encounter with a pathogen. Persistent inflammation, neutrophil infiltration and restructuring of the extracellular matrix are defects that resemble those seen in bone infection and in some chondropathies. As the notochord is a transient embryonic structure that is closely related to cartilage and bone and that contributes to vertebral column formation, we propose infection of the notochord in zebrafish larvae as a new model to study the cellular and molecular mechanisms underlying cartilage and bone inflammation.

  2. Transient infection of the zebrafish notochord with E. coli induces chronic inflammation.

    Science.gov (United States)

    Nguyen-Chi, Mai; Phan, Quang Tien; Gonzalez, Catherine; Dubremetz, Jean-François; Levraud, Jean-Pierre; Lutfalla, Georges

    2014-07-01

    Zebrafish embryos and larvae are now well-established models in which to study infectious diseases. Infections with non-pathogenic Gram-negative Escherichia coli induce a strong and reproducible inflammatory response. Here, we study the cellular response of zebrafish larvae when E. coli bacteria are injected into the notochord and describe the effects. First, we provide direct evidence that the notochord is a unique organ that is inaccessible to leukocytes (macrophages and neutrophils) during the early stages of inflammation. Second, we show that notochord infection induces a host response that is characterised by rapid clearance of the bacteria, strong leukocyte recruitment around the notochord and prolonged inflammation that lasts several days after bacteria clearance. During this inflammatory response, il1b is first expressed in macrophages and subsequently at high levels in neutrophils. Moreover, knock down of il1b alters the recruitment of neutrophils to the notochord, demonstrating the important role of this cytokine in the maintenance of inflammation in the notochord. Eventually, infection of the notochord induces severe defects of the notochord that correlate with neutrophil degranulation occurring around this tissue. This is the first in vivo evidence that neutrophils can degranulate in the absence of a direct encounter with a pathogen. Persistent inflammation, neutrophil infiltration and restructuring of the extracellular matrix are defects that resemble those seen in bone infection and in some chondropathies. As the notochord is a transient embryonic structure that is closely related to cartilage and bone and that contributes to vertebral column formation, we propose infection of the notochord in zebrafish larvae as a new model to study the cellular and molecular mechanisms underlying cartilage and bone inflammation. © 2014. Published by The Company of Biologists Ltd.

  3. Acute phase response in two consecutive experimentally induced E. coli intramammary infections in dairy cows

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    Saatsi Johanna

    2008-06-01

    Full Text Available Abstract Background Acute phase proteins haptoglobin (Hp, serum amyloid A (SAA and lipopolysaccharide binding protein (LBP have suggested to be suitable inflammatory markers for bovine mastitis. The aim of the study was to investigate acute phase markers along with clinical parameters in two consecutive intramammary challenges with Escherichia coli and to evaluate the possible carry-over effect when same animals are used in an experimental model. Methods Mastitis was induced with a dose of 1500 cfu of E. coli in one quarter of six cows and inoculation repeated in another quarter after an interval of 14 days. Concentrations of acute phase proteins haptoglobin (Hp, serum amyloid A (SAA and lipopolysaccharide binding protein (LBP were determined in serum and milk. Results In both challenges all cows became infected and developed clinical mastitis within 12 hours of inoculation. Clinical disease and acute phase response was generally milder in the second challenge. Concentrations of SAA in milk started to increase 12 hours after inoculation and peaked at 60 hours after the first challenge and at 44 hours after the second challenge. Concentrations of SAA in serum increased more slowly and peaked at the same times as in milk; concentrations in serum were about one third of those in milk. Hp started to increase in milk similarly and peaked at 36–44 hours. In serum, the concentration of Hp peaked at 60–68 hours and was twice as high as in milk. LBP concentrations in milk and serum started to increase after 12 hours and peaked at 36 hours, being higher in milk. The concentrations of acute phase proteins in serum and milk in the E. coli infection model were much higher than those recorded in experiments using Gram-positive pathogens, indicating the severe inflammation induced by E. coli. Conclusion Acute phase proteins would be useful parameters as mastitis indicators and to assess the severity of mastitis. If repeated experimental intramammary

  4. E. Coli Infections

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    E. coli is the name of a type of bacteria that lives in your intestines. Most types of E. coli are harmless. However, some types can make you ... type causes travelers' diarrhea. The worst type of E. coli causes bloody diarrhea, and can sometimes cause kidney ...

  5. Insect cells are superior to Escherichia coli in producing malaria proteins inducing IgG targeting PfEMP1 on infected erythrocytes

    DEFF Research Database (Denmark)

    Victor, Michala E; Bengtsson, Anja; Andersen, Gorm

    2010-01-01

    -exposed epitopes are unknown. An insect cell and Escherichia coli based system was used to express single and double domains encoded by the pfd1235w var gene. The resulting recombinant proteins have been evaluated for yield and purity and their ability to induce rat antibodies, which react with the native PFD1235w...... PfEMP1 antigen expressed on 3D7PFD1235w-IE. Their recognition by human anti-malaria antibodies from previously infected Tanzanian donors was also analysed....

  6. Insect cells are superior to Escherichia coli in producing malaria proteins inducing IgG targeting PfEMP1 on infected erythrocytes

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    Joergensen Louise

    2010-11-01

    Full Text Available Abstract Background The PFD1235w Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1 antigen is associated with severe malaria in children and can be expressed on the surface of infected erythrocytes (IE adhering to ICAM1. However, the exact three-dimensional structure of this PfEMP1 and its surface-exposed epitopes are unknown. An insect cell and Escherichia coli based system was used to express single and double domains encoded by the pfd1235w var gene. The resulting recombinant proteins have been evaluated for yield and purity and their ability to induce rat antibodies, which react with the native PFD1235w PfEMP1 antigen expressed on 3D7PFD1235w-IE. Their recognition by human anti-malaria antibodies from previously infected Tanzanian donors was also analysed. Methods The recombinant proteins were run on SDS-PAGE and Western blots for quantification and size estimation. Insect cell and E. coli-produced recombinant proteins were coupled to a bead-based Luminex assay to measure the plasma antibody reactivity of 180 samples collected from Tanzanian individuals. The recombinant proteins used for immunization of rats and antisera were also tested by flow cytometry for their ability to surface label 3D7PFD1235w-IE. Results All seven pAcGP67A constructs were successfully expressed as recombinant protein in baculovirus-infected insect cells and subsequently produced to a purity of 60-97% and a yield of 2-15 mg/L. By comparison, only three of seven pET101/D-TOPO constructs expressed in the E. coli system could be produced at all with purity and yield ranging from 3-95% and 6-11 mg/L. All seven insect cell, but only two of the E. coli produced proteins induced antibodies reactive with native PFD1235w expressed on 3D7PFD1235w-IE. The recombinant proteins were recognized in an age- and transmission intensity-dependent manner by antibodies from 180 Tanzanian individuals in a bead-based Luminex assay. Conclusions The baculovirus based insect cell

  7. Saccharomyces boulardii Preserves the Barrier Function and Modulates the Signal Transduction Pathway Induced in Enteropathogenic Escherichia coli-Infected T84 Cells

    Science.gov (United States)

    Czerucka, Dorota; Dahan, Stephanie; Mograbi, Baharia; Rossi, Bernard; Rampal, Patrick

    2000-01-01

    Use of the nonpathogenic yeast Saccharomyces boulardii in the treatment of infectious diarrhea has attracted growing interest. The present study designed to investigate the effect of this yeast on enteropathogenic Escherichia coli (EPEC)-associated disease demonstrates that S. boulardii abrogated the alterations induced by an EPEC strain on transepithelial resistance, [3H]inulin flux, and ZO-1 distribution in T84 cells. Moreover, EPEC-mediated apoptosis of epithelial cells was delayed in the presence of S. boulardii. The yeast did not modify the number of adherent bacteria but lowered by 50% the number of intracellular bacteria. Infection by EPEC induced tyrosine phosphorylation of several proteins in T84 cells, including p46 and p52 SHC isoforms, that was attenuated in the presence of S. boulardii. Similarly, EPEC-induced activation of the ERK1/2 mitogen-activated protein (MAP) kinase pathway was diminished in the presence of the yeast. Interestingly, inhibition of the ERK1/2 pathway with the specific inhibitor PD 98059 decreased EPEC internalization, suggesting that modulation of the ERK1/2 MAP pathway might account for the lowering of the number of intracellular bacteria observed in the presence of S. boulardii. Altogether, this study demonstrated that S. boulardii exerts a protective effect on epithelial cells after EPEC adhesion by modulating the signaling pathway induced by bacterial infection. PMID:10992512

  8. Experimental induced avian E. coli salpingitis

    DEFF Research Database (Denmark)

    Olsen, Rikke Heidemann; Thøfner, Ida; Pors, Susanne Elisabeth

    2016-01-01

    Several types of Escherichia coli have been associated with extra-intestinal infections in poultry, however, they may vary significantly in their virulence potential. The aim of the present study was to investigate the virulence of five strains of E. coli obtained from different disease......) had a distinct ability to cause disease. Results of the study shows major differences in virulence of different strains of E. coli in ascending infections; however, there was no indication of tissue-specific adaptation, since strains obtained from lesions unrelated to the reproductive system were...... fully capable of causing experimental infection. In conclusion, the study provides evidence for the clinical outcome of infection with E. coli in poultry is largely influenced by the specific strain as well as individual host factors....

  9. 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 ...

  10. neonatal infections caused by escherichia coli at the national

    African Journals Online (AJOL)

    boaz

    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 ...

  11. Annual Surveillance Summary: Escherichia coli (E. coli) Infections in the Military Health System (MHS), 2015

    Science.gov (United States)

    2017-03-01

    Annual Surveillance Summary: Escherichia coli ( E . coli ) Infections in the Military Health System (MHS...or position of the Department of the Navy, Department of Defense, nor the U.S. Government. i i E . coli in the MHS: Annual Summary 2015 Prepared...March 2017 EpiData Center Department NMCPHC-EDC-TR-187-2017 ii ii E . coli in the MHS: Annual Summary 2015 Prepared March 2017 EpiData

  12. Radiosynthesis and Biodistribution of 99mTc-Metronidazole as an Escherichia coli Infection Imaging Radiopharmaceutical.

    Science.gov (United States)

    Iqbal, Anam; Naqvi, Syed Ali Raza; Rasheed, Rashid; Mansha, Asim; Ahmad, Matloob; Zahoor, Ameer Fawad

    2018-05-01

    Bacterial infection poses life-threatening challenge to humanity and stimulates to the researchers for developing better diagnostic and therapeutic agents complying with existing theranostic techniques. Nuclear medicine technique helps to visualize hard-to-diagnose deep-seated bacterial infections using radionuclide-labeled tracer agents. Metronidazole is an antiprotozoal antibiotic that serves as a preeminent anaerobic chemotherapeutic agent. The aim of this study was to develop technetium-99m-labeled metronidazole radiotracer for the detection of deep-seated bacterial infections. Radiosynthesis of 99m Tc-metronidazole was carried by reacting reduced technetium-99m and metronidazole at neutral pH for 30 min. The stannous chloride dihydrate was used as the reducing agent. At optimum radiolabeling conditions, ~ 94% radiochemical was obtained. Quality control analysis was carried out with a chromatographic paper and instant thin-layer chromatographic analysis. The biodistribution study of radiochemical was performed using Escherichia coli bacterial infection-induced rat model. The scintigraphic study was performed using E. coli bacterial infection-induced rabbit model. The results showed promising accumulation at the site of infection and its rapid clearance from the body. The tracer showed target-to-non-target ratio 5.57 ± 0.04 at 1 h post-injection. The results showed that 99m Tc-MNZ has promising potential to accumulate at E. coli bacterial infection that can be used for E. coli infection imaging.

  13. Predictors Of Non-Escherichia Coli Urinary Tract Infection.

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    Shaikh, Nader; Wald, Ellen R; Keren, Ron; Gotman, Nathan; Ivanova, Anastasia; Carpenter, Myra A; Moxey-Mims, Marva; Hoberman, Alejandro

    2016-11-01

    We aimed to determine which children are prone to non-Escherichia coli urinary tract infection (UTIs). We included 769 children with UTI. We found that circumcised males, Hispanic children, children without fever and children with grades 3 and 4 vesicoureteral reflux were more likely to have a UTI caused by organisms other than E. coli. This information may guide clinicians in their choice of antimicrobial therapy.

  14. Pathological And Immunological Study On Infection With Escherichia Coli In ale BALB/c mice

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    Ali, Intisar H.; Jabir, Majid S.; Al-Shmgani, Hanady S. A.; Sulaiman, Ghassan M.; Sadoon, Ali H.

    2018-05-01

    Escherichia coli bacteria is considered as one of the common responsible for the frequency and severity of infections that it hospitalized patients. E. coli simultaneously carries a harmful side in which only a slight genetic recombination can bring about a highly pathogenic strain that most frequently causes the scourge of bacterial infections worldwide including sepsis, neonatal meningitis, pneumonia, bacteremia and traveler’s diarrhea. This study was carried out to assess Escherichia coli infection induced pathologically and immunologically. Following Escherichia coli isolation, identification and counting, the lethal dose (LD-50) was determined before infection. Twenty-two mice were used in this study for 21 days infection, the animals were sacrificed at 3, 6, 9, 12, 15, 18 and 21 days, and tissues of different tissue were collected, examined for bacterial infection. Bacteria and mice immunization and ELISA were used to detect immunoglobulin G level in serum as well. For histological study, different infected organs were used. The results indicated that the LH50 was 1×109 cell; and all organs were infected after 3 days followed by decreased in infection level shown in brain at day 12, lung, kidney and intestine at day 15 and in liver, spleen and heart at day 21. Moreover, ELISA results revealed that concentration 1:200 of serum in positive and negative state and optimum concentration of Ag 1:40 dilution and compact dilution is 1:1000. In addition, diversity of histopathological alteration occurs in tissue on time-depended manner. This study concluded that the ability of activated E.coli to stimulate the intestinal secretory immune system of germ might result from a retardation of immunological maturity.

  15. Causes, prevention and treatment of Escherichia coli infections.

    Science.gov (United States)

    Gould, Dinah

    Escherichia coli is a normal inhabitant of the human gastrointestinal tract and can cause healthcare-associated infections. The organism is most frequently responsible for urinary tract infections and it is the bacterium most often implicated in the cause of diarrhoea in people travelling overseas. In recent years, a strain called Ecoli O157 has gained notoriety for causing foodborne infection, which can have severe health consequences, especially in young children. This article describes the range of different infections caused by Ecoli in healthcare settings and the community and discusses the characteristics of the different strains of the bacteria that explain variations in their pathogenicity.

  16. 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...

  17. 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...... from UTI patients, community-dwelling humans, broiler chicken meat, pork, and broiler chicken, previously identified to exhibit eight virulence genotypes by microarraydetection of approximately 300 genes, were investigated for clonal relatedness by PFGE. Nine isolates were selected and tested...... for in vivo virulence in the mouse model of ascending UTI. UTI and community-dwelling human strains were closely clonally related to meat strains. Several human derived strains were also clonally interrelated. All nine isolates regardless of origin were virulent in the UTI model with positive urine, bladder...

  18. Faecal Escherichia coli from patients with E. coli urinary tract infection and healthy controls who have never had a urinary tract infection

    DEFF Research Database (Denmark)

    Nielsen, Karen L; Dynesen, Pia; Larsen, Preben

    2014-01-01

    Urinary tract infections (UTIs) are primarily caused by Escherichia coli with the patient's own faecal flora acting as a reservoir for the infecting E. coli. Here we sought to characterize the E. coli faecal flora of UTI patients and healthy controls who had never had a UTI. Up to 20 E. coli...... colonies from each rectal swab were random amplified polymorphic DNA (RAPD) typed for clonality, dominance in the sample and correlation to the infecting UTI isolate in patients. Each distinct clone was phylotyped and tested for antimicrobial susceptibility. Eighty-seven per cent of the UTI patients...... carried the infecting strain in their faecal flora, and faecal clones causing UTI were more often dominant in the faecal flora. Patients had a larger diversity of E. coli in their gut flora by carrying more unique E. coli clones compared to controls, and patient faecal clones were more often associated...

  19. Immunomodulation of Host Chitinase 3-Like 1 During a Mammary Pathogenic Escherichia coli Infection

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    Koen Breyne

    2018-05-01

    Full Text Available Chitin is a N-acetyl-d-glucosamine biopolymer that can be recognized by chitin-binding proteins. Although mammals lack chitin synthase, they induce proteins responsible for detecting chitin in response to bacterial infections. Our aim was to investigate whether chitinase 3-like 1 (CHI3L1 has a potential role in the innate immunity of the Escherichia coli (E. coli infected mammary gland. CHI3L1 protein was found to be secreted in whey of naturally coliform-affected quarters compared to whey samples isolated from healthy udders. In addition, gene expression of CHI3L1 was confirmed in udder tissue of cows experimentally infected with a mammary pathogenic E. coli (MPEC strain. Despite the known anatomical differences, the bovine udders’ innate immune response was mimicked by applying an experimental mouse model using MPEC or non-MPEC isolates. The effect of CHI3L1 expression in the murine mammary gland in response to coliform bacteria was investigated through the use of CHI3L1−/− mice as well as through treatment with either a pan-caspase inhibitor or chitin particles in wild-type mice. The local induction of CHI3L1 postinfection with different E. coli strains was demonstrated to be independent of both bacterial growth and mammary interleukin (IL-8 levels. Indeed, CHI3L1 emerged as a regulator impacting on the transcytosis of Ly6G-positive cells from the interstitial space into the alveolar lumen of the mammary tissue. Furthermore, CHI3L1 was found to be upstream regulated by caspase activity and had a major downstream effect on the local pro-inflammatory cytokine profile, including IL-1beta, IL-6, and RANTES/CCL5. In conclusion, CHI3L1 was demonstrated to play a key role in the cytokine and caspase signaling during E. coli triggered inflammation of the mammary gland.

  20. Radiocomplexation and evaluation of the 99mTc-Gemifloxacin in artificially Escherichia coli infected mice

    International Nuclear Information System (INIS)

    Erfani, M.; Shafiei, M.; Rekabgardan, M.; Mortazavi, P.

    2016-01-01

    Gemifloxacin as a broad spectrum quinolone antibacterial agent was radiocomplexed with high activity of 99m Tc and was evaluated as an infection imaging agent in artificially Escherichia coli (E. Coli) infected mice. 99m Tc-Gemifloxacin with high specific activity (0.148 GBq/μmol) and labeling yield (98.60 ± 0.70 %) was obtained. Our main achievement was high accumulation in the E. Coli infected right thigh muscle in mice (T/NT = 1.89 at 4 h post injection) which may diagnostically be beneficial to distinguish sites of E. Coli infection. (author)

  1. Consequences of concurrent Ascaridia galli and Escherichia coli infections in chickens

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    Permin A

    2006-03-01

    Full Text Available Three experiments were carried out to examine the consequences of concurrent infections with Ascaridia galli and Escherichia coli in chickens raised for table egg production. Characteristic pathological lesions including airsacculitis, peritonitis and/or polyserositis were seen in all groups infected with E. coli. Furthermore, a trend for increased mortality rates was observed in groups infected with both organisms which, however, could not be confirmed statistically. The mean worm burden was significantly lower in combined infection groups compared to groups infected only with A. galli. It was also shown that combined infections of E. coli and A. galli had an added significant negative impact on weight gain.

  2. 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...

  3. Comparative therapeutic activities of Ciprofloxacin, Amoxicillin, Ceftriaxone and Cotrimoxazole in a new model of experimental infection with Escherichia coli

    OpenAIRE

    Hof, H.; Christen, A.; Hacker, Jörg

    2009-01-01

    A new mouse model for systemic infection with Escherichia coli is presented. Whereas in other models 107_108 bacteria have to be injected into an animal to induce toxic effects resulting in death within 24 hours, now, only 103_104 bacteria of an appropriate strain are required to produce a genuine infection characterized by an increase in the bacterial load over several days. The quantitative determination of bacterial counts per liver allows a more sensitive measurement than recording death ...

  4. Evaluation of Colicin Effect on the Induction of Treated Mice in Prevention of Infection Caused by Escherichia coli K99

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    Yahya Tahamtan

    2016-11-01

    Full Text Available Background. Colicin produce by colicinogenic E. coli (CEC arenarrow limited spectrum antimicrobial agents that are able to kill or prevent close related strains. Objective. The objective of this study was to evaluation effect of Colicin to induce immunized mice to prevent infection caused by E. coliK99. Patient and Methods. The experiment was conducted into two mice groups (30 in each group with two weeks old. All mice were administered by streptomycin sulfate prior to treatment to eliminate resident E. coli. Group one was orally inoculated with PBS as control and the second was immunized by Colicin solution as immunize group. Both control and immunized group were challenged by 3 LD 50 of E. coli K99 and follow a week. Results. Immunized mice group were not showed severe clinical signs. While diarrhea with different sings of colibaccillosis was established in control group and infected mice was died. Conclusion. Overuse antibiotics developed serious new types of multi drug resistance in human medicine and therefore has limited their use in farm animals. The study indicates the use of Colicin and biotherapy instead of antibiotic is more safe and efficient for control of E. coliK99 infection. Immunized mice by Colicin solution protected E. coli K99 colonization and reduce fecal shedding. Investigation in livestock for applying Colicin in farm animal is recommended.

  5. A Canadian Multicentre Case-Control Study of Sporadic Escherichia coli 0157:H7 Infection

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    Donna Holton

    1999-01-01

    Full Text Available OBJECTIVE: To evaluate further risk factors for Escherichia coli 0157:H7 infection including consumer preferences related to the consumption of ground beef and the role of person-to-person transmission of this infection.

  6. Physicochemical Factors: Impact on Spermagglutination Induced by Escherichia coli

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    Kiranjeet Kaur

    2014-02-01

    Full Text Available Motility is a sensitive parameter of sperm function which is predictive of its fertilization potential in vitro. The decrease in sperm motility may be associated with sperm agglutination and immobilization due to mere presence of bacteria or excretion of bacterial toxic products. Supplementation with various agents like sucrose, mannitol, calcium, and EDTA is well known to improve the sperm motility in vitro. The present study was designed to check any protective role exerted by the addition of different agents on spermatozoal motility against E. coli induced sperm agglutination. 52 semen specimens were screened for the presence of sperm-agglutinating strain of E. coli. Further, influence of various factors, namely, sugars, salts, and chelating agents was studied. Also, the impact of exposure to high temperature and alcohol on sperm-agglutinating efficiency of E. coli was observed. None of the factors could inhibit the sperm agglutination induced by E. coli, except high temperature suggesting the involvement of protein moiety. In addition, it was observed that agglutinating efficiency of E. coli was limited to spermatozoa and RBCs. It may be concluded that sperm-agglutinating property of E. coli is quite stable as various physicochemical factors tested did not show any negative effect on the same except high temperature.

  7. Molecular characterization of some new E. coli strains theoretically responsible for both intestinal and extraintestinal infections

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    Ghaleb Adwan

    2016-06-01

    Full Text Available Strains of E. coli are divided into 3 major groups; commensal strains, diarrheagenic (intestinal E. coli pathotypes and extraintestinal pathogenic E. coli. Extraintestinal pathogenic E. coli are unlike diarrheagenic pathotypes, they have not ability to cause intestinal disease in human, but they have normal ability for long-term colonization in the gut. This study aimed to spotlight on that intestinal and extraintestinal infections are not restricted to intestinal pathotypes and extraintestinal pathogenic E. coli, respectively. A total of 102 uropathogenic E. coli isolates were collected during 2012 and 2015. A multiplex PCR was used to detect phylogenetic groups, virulence factors for extraintestinal pathogenic E. coli and intestinal E. coli pathotypes genes. Results of this research showed that 12 (11.8% uropathogenic E. coli isolates had genes that are theoretically responsible for intestinal diseases, were 10 of these isolates belonged to phylogentic group D and 2 isolates to phylogentic group A. We conclude from these results, this is the first report on the molecular characterization of E. coli that theoretically can cause both intestinal and extraintestinal infections simultaneously. The presence of these strains has a great impact on public health. More studies are necessary before definitive conclusions if these strains are a different clone that theoretically have ability to cause both intestinal and extraintestinal infections and belonged to phylogenetic groups other than A and D. Products of diarrheagenic genes in UPEC strains need further studies to detect their effects in intestinal infections

  8. Transcriptional profiling of the bovine hepatic response to experimentally induced E. coli mastitis

    DEFF Research Database (Denmark)

    Jørgensen, Hanne Birgitte Hede; Buitenhuis, Bart; Røntved, Christine Maria

    2012-01-01

    The mammalian liver works to keep the body in a state of homeostasis and plays an important role in systemic acute phase response to infections. In this study we investigated the bovine hepatic acute phase response at the gene transcription level in dairy cows with experimentally E. coli-induced ......The mammalian liver works to keep the body in a state of homeostasis and plays an important role in systemic acute phase response to infections. In this study we investigated the bovine hepatic acute phase response at the gene transcription level in dairy cows with experimentally E. coli......-induced mastitis. At time = 0, each of 16 periparturient dairy cows received 20-40 CFU of live E. coli in one front quarter of the udder. A time series of liver biopsies was collected at -144, 12, 24 and 192 hours relative to time of inoculation. Changes in transcription levels in response to E. coli inoculation...... were analyzed using the Bovine Genome Array and tested significant for 408 transcripts over the time series (adjusted p0.05; abs(fold-change)>2). After 2-D clustering, transcripts represented three distinct transcription profiles: 1) regulation of gene transcription and apoptosis, 2) responses...

  9. Inhibition of Inducible Nitric Oxide Controls Pathogen Load and Brain Damage by Enhancing Phagocytosis of Escherichia coli K1 in Neonatal Meningitis

    OpenAIRE

    Mittal, Rahul; Gonzalez-Gomez, Ignacio; Goth, Kerstin A.; Prasadarao, Nemani V.

    2010-01-01

    Escherichia coli K1 is a leading cause of neonatal meningitis in humans. In this study, we sought to determine the pathophysiologic relevance of inducible nitric oxide (iNOS) in experimental E. coli K1 meningitis. By using a newborn mouse model of meningitis, we demonstrate that E. coli infection triggered the expression of iNOS in the brains of mice. Additionally, iNOS−/− mice were resistant to E. coli K1 infection, displaying normal brain histology, no bacteremia, no disruption of the blood...

  10. The redistribution of granulocytes following E. coli endotoxin induced sepsis

    DEFF Research Database (Denmark)

    Toft, P; Lillevang, S T; Tønnesen, Else Kirstine

    1994-01-01

    Infusion of endotoxin elicits granulocytopenia followed by increased numbers of granulocytes in peripheral blood. The purpose of this study was to investigate the redistribution and sequestration of granulocytes in the tissues following E. coli endotoxin induced sepsis. From 16 rabbits granulocytes...

  11. Biological Activities of Uric Acid in Infection Due to Enteropathogenic and Shiga-Toxigenic Escherichia coli

    Science.gov (United States)

    Broome, Jacqueline E.; Lis, Agnieszka

    2016-01-01

    In previous work, we identified xanthine oxidase (XO) as an important enzyme in the interaction between the host and enteropathogenic Escherichia coli (EPEC) and Shiga-toxigenic E. coli (STEC). Many of the biological effects of XO were due to the hydrogen peroxide produced by the enzyme. We wondered, however, if uric acid generated by XO also had biological effects in the gastrointestinal tract. Uric acid triggered inflammatory responses in the gut, including increased submucosal edema and release of extracellular DNA from host cells. While uric acid alone was unable to trigger a chloride secretory response in intestinal monolayers, it did potentiate the secretory response to cyclic AMP agonists. Uric acid crystals were formed in vivo in the lumen of the gut in response to EPEC and STEC infections. While trying to visualize uric acid crystals formed during EPEC and STEC infections, we noticed that uric acid crystals became enmeshed in the neutrophilic extracellular traps (NETs) produced from host cells in response to bacteria in cultured cell systems and in the intestine in vivo. Uric acid levels in the gut lumen increased in response to exogenous DNA, and these increases were enhanced by the actions of DNase I. Interestingly, addition of DNase I reduced the numbers of EPEC bacteria recovered after a 20-h infection and protected against EPEC-induced histologic damage. PMID:26787720

  12. Vaginal versus Obstetric Infection Escherichia coli Isolates among Pregnant Women: Antimicrobial Resistance and Genetic Virulence Profile.

    Directory of Open Access Journals (Sweden)

    Emma Sáez-López

    Full Text Available Vaginal Escherichia coli colonization is related to obstetric infections and the consequent development of infections in newborns. Ampicillin resistance among E. coli strains is increasing, which is the main choice for treating empirically many obstetric and neonatal infections. Vaginal E. coli strains are very similar to extraintestinal pathogenic E. coli with regards to the virulence factors and the belonging to phylogroup B2. We studied the antimicrobial resistance and the genetic virulence profile of 82 E. coli isolates from 638 vaginal samples and 63 isolated from endometrial aspirate, placental and amniotic fluid samples from pregnant women with obstetric infections. The prevalence of E. coli in the vaginal samples was 13%, which was significant among women with associated risk factors during pregnancy, especially premature preterm rupture of membranes (p<0.0001. Sixty-five percent of the strains were ampicillin-resistant. The E. coli isolates causing obstetric infections showed higher resistance levels than vaginal isolates, particularly for gentamicin (p = 0.001. The most prevalent virulence factor genes were those related to the iron uptake systems revealing clear targets for interventions. More than 50% of the isolates belonged to the virulent B2 group possessing the highest number of virulence factor genes. The ampicillin-resistant isolates had high number of virulence factors primarily related to pathogenicity islands, and the remarkable gentamicin resistance in E. coli isolates from women presenting obstetric infections, the choice of the most appropriate empiric treatment and clinical management of pregnant women and neonates should be carefully made. Taking into account host-susceptibility, the heterogeneity of E. coli due to evolution over time and the geographical area, characterization of E. coli isolates colonizing the vagina and causing obstetric infections in different regions may help to develop interventions and avoid the

  13. Development of a Vaccine against Escherichia coli Urinary Tract Infections

    Directory of Open Access Journals (Sweden)

    Harry L. T. Mobley

    2015-12-01

    Full Text Available Urinary tract infection (UTI is the second most common infection in humans after those involving the respiratory tract. This results not only in huge annual economic costs, but in decreased workforce productivity and high patient morbidity. Most infections are caused by uropathogenic Escherichia coli (UPEC. Antibiotic treatment is generally effective for eradication of the infecting strain; however, documentation of increasing antibiotic resistance, allergic reaction to certain pharmaceuticals, alteration of normal gut flora, and failure to prevent recurrent infections represent significant barriers to treatment. As a result, approaches to prevent UTI such as vaccination represent a gap that must be addressed. Our laboratory has made progress toward development of a preventive vaccine against UPEC. The long-term research goal is to prevent UTIs in women with recurrent UTIs. Our objective has been to identify the optimal combination of protective antigens for inclusion in an effective UTI vaccine, optimal adjuvant, optimal dose, and optimal route of delivery. We hypothesized that a multi-subunit vaccine elicits antibody that protects against experimental challenge with UPEC strains. We have systematically identified four antigens that can individually protect experimentally infected mice from colonization of the bladder and/or kidneys by UPEC when administered intranasally with cholera toxin (CT as an adjuvant. To advance the vaccine for utility in humans, we will group the individual antigens, all associated with iron acquisition (IreA, Hma, IutA, FyuA, into an effective combination to establish a multi-subunit vaccine. We demonstrated for all four vaccine antigens that antigen-specific serum IgG represents a strong correlate of protection in vaccinated mice. High antibody titers correlate with low colony forming units (CFUs of UPEC following transurethral challenge of vaccinated mice. However, the contribution of cell-mediated immunity cannot

  14. The redistribution of granulocytes following E. coli endotoxin induced sepsis

    DEFF Research Database (Denmark)

    Toft, P; Lillevang, S T; Tønnesen, Else Kirstine

    1994-01-01

    Infusion of endotoxin elicits granulocytopenia followed by increased numbers of granulocytes in peripheral blood. The purpose of this study was to investigate the redistribution and sequestration of granulocytes in the tissues following E. coli endotoxin induced sepsis. From 16 rabbits granulocytes...... were isolated, labelled with Indium and reinjected intravenously. Eight rabbits received an infusion of E. coli endotoxin 2 micrograms kg-1 while eight received isotonic saline. The redistribution of granulocytes was imaged with a gamma camera and calculated with a connected computer before and 2 and 6...... hours after infusion of endotoxin or saline. Serum cortisol and interleukin-1 beta were measured. In another seven rabbits, respiratory burst activity and degranulation of granulocytes were measured prior to and from 5 min to 6 hours after infusion of E. coli endotoxin 2 micrograms kg-1 BW. Following...

  15. Prevalence of Balantidium coli Infection in Bred Rhesus Monkeys (Macaca mulatta in Guangxi, southern China.

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    Hai Long Li

    2014-03-01

    Full Text Available Balantidium coli infects humans, primates and pigs, causing serious diarrhea and dysentery. Little information on the prevalence of B. coli in primates is available in China. This investigation was conducted to determine the prevalence of B. coli infection in bred rhesus monkeys in Guangxi Zhuang Nationality Autonomous Region (GZNAR, southern China.A total of 120 fecal samples were collected from rhesus monkeys bred in cages in GZNAR and B. coli cysts and/or trophozoites were examined microscopically after sedimentation with water in May 2013.(64.2% samples were tested positive. The prevalence was 65% (39/60 and 63.3% (38/60 in female and male monkeys, respectively. 80% (48/60 cages in this nonhuman primate center were positive for B. coli.The present survey revealed high circulation of B. coli in bred rhesus monkeys in GZNAR, which poses potential threats to animal and human health.

  16. Comparative proteomic analysis of proteins expression changes in the mammary tissue of cows infected with Escherichia coli mastitis.

    Science.gov (United States)

    Zhao, Xiao-wei; Yang, Yong-xin; Huang, Dong-wei; Cheng, Guang-long; Zhao, Hui-ling

    2015-01-01

    Cows infected with Escherichia (E.) coli usually experience severe clinical symptoms, including damage to mammary tissues, reduced milk yield, and altered milk composition. In order to investigate the host response to E. coli infection and discover novel markers for mastitis treatment, mammary tissue samples were collected from healthy cows and bovines with naturally occurring severe E. coli mastitis. Changes of mammary tissue proteins were examined using two-dimensional gel electrophoresis and label-free proteomic approaches. A total of 95 differentially expressed proteins were identified. Of these, 56 proteins were categorized according to molecular function, cellular component, and biological processes. The most frequent biological processes influenced by the proteins were response to stress, transport, and establishment of localization. Furthermore, a network analysis of the proteins with altered expression in mammary tissues demonstrated that these factors are predominantly involved with binding and structural molecule activities. Vimentin and a-enolase were central "functional hubs" in the network. Based on results from the present study, disease-induced alterations of protein expression in mammary glands and potential markers for the effective treatment of E. coli mastitis were identified. These data have also helped elucidate defense mechanisms that protect the mammary glands and promote the pathogenesis of E. coli mastitis.

  17. Urothelial CD44 facilitates Escherichia coli infection of the murine urinary tract

    NARCIS (Netherlands)

    Rouschop, Kasper M. A.; Sylva, Marc; Teske, Gwendoline J. D.; Hoedemaeker, Inge; Pals, Steven T.; Weening, Jan J.; van der Poll, Tom; Florquin, Sandrine

    2006-01-01

    Escherichia coli is the most common pathogen found in urinary tract infections (UTIs), mainly affecting children and women. We report that CD44, a hyaluronic acid (HA) binding protein that mediates cell-cell and cell-matrix interactions, facilitates the interaction of E. coli with urothelial cells

  18. Vaginal versus Obstetric Infection Escherichia coli Isolates among Pregnant Women: Antimicrobial Resistance and Genetic Virulence Profile.

    Science.gov (United States)

    Sáez-López, Emma; Guiral, Elisabet; Fernández-Orth, Dietmar; Villanueva, Sonia; Goncé, Anna; López, Marta; Teixidó, Irene; Pericot, Anna; Figueras, Francesc; Palacio, Montse; Cobo, Teresa; Bosch, Jordi; Soto, Sara M

    2016-01-01

    Vaginal Escherichia coli colonization is related to obstetric infections and the consequent development of infections in newborns. Ampicillin resistance among E. coli strains is increasing, which is the main choice for treating empirically many obstetric and neonatal infections. Vaginal E. coli strains are very similar to extraintestinal pathogenic E. coli with regards to the virulence factors and the belonging to phylogroup B2. We studied the antimicrobial resistance and the genetic virulence profile of 82 E. coli isolates from 638 vaginal samples and 63 isolated from endometrial aspirate, placental and amniotic fluid samples from pregnant women with obstetric infections. The prevalence of E. coli in the vaginal samples was 13%, which was significant among women with associated risk factors during pregnancy, especially premature preterm rupture of membranes (pinfections showed higher resistance levels than vaginal isolates, particularly for gentamicin (p = 0.001). The most prevalent virulence factor genes were those related to the iron uptake systems revealing clear targets for interventions. More than 50% of the isolates belonged to the virulent B2 group possessing the highest number of virulence factor genes. The ampicillin-resistant isolates had high number of virulence factors primarily related to pathogenicity islands, and the remarkable gentamicin resistance in E. coli isolates from women presenting obstetric infections, the choice of the most appropriate empiric treatment and clinical management of pregnant women and neonates should be carefully made. Taking into account host-susceptibility, the heterogeneity of E. coli due to evolution over time and the geographical area, characterization of E. coli isolates colonizing the vagina and causing obstetric infections in different regions may help to develop interventions and avoid the aetiological link between maternal carriage and obstetric and subsequent puerperal infections.

  19. Fitness of Escherichia coli during urinary tract infection requires gluconeogenesis and the TCA cycle.

    Directory of Open Access Journals (Sweden)

    Christopher J Alteri

    2009-05-01

    Full Text Available Microbial pathogenesis studies traditionally encompass dissection of virulence properties such as the bacterium's ability to elaborate toxins, adhere to and invade host cells, cause tissue damage, or otherwise disrupt normal host immune and cellular functions. In contrast, bacterial metabolism during infection has only been recently appreciated to contribute to persistence as much as their virulence properties. In this study, we used comparative proteomics to investigate the expression of uropathogenic Escherichia coli (UPEC cytoplasmic proteins during growth in the urinary tract environment and systematic disruption of central metabolic pathways to better understand bacterial metabolism during infection. Using two-dimensional fluorescence difference in gel electrophoresis (2D-DIGE and tandem mass spectrometry, it was found that UPEC differentially expresses 84 cytoplasmic proteins between growth in LB medium and growth in human urine (P<0.005. Proteins induced during growth in urine included those involved in the import of short peptides and enzymes required for the transport and catabolism of sialic acid, gluconate, and the pentose sugars xylose and arabinose. Proteins required for the biosynthesis of arginine and serine along with the enzyme agmatinase that is used to produce the polyamine putrescine were also up-regulated in urine. To complement these data, we constructed mutants in these genes and created mutants defective in each central metabolic pathway and tested the relative fitness of these UPEC mutants in vivo in an infection model. Import of peptides, gluconeogenesis, and the tricarboxylic acid cycle are required for E. coli fitness during urinary tract infection while glycolysis, both the non-oxidative and oxidative branches of the pentose phosphate pathway, and the Entner-Doudoroff pathway were dispensable in vivo. These findings suggest that peptides and amino acids are the primary carbon source for E. coli during infection of

  20. "Population structure of drug-susceptible, -resistant and ESBL-producing Escherichia coli from community-acquired urinary tract infections"

    DEFF Research Database (Denmark)

    Hertz, Frederik Boetius; Nielsen, Jesper Boye; Schønning, Kristian

    2016-01-01

    BACKGROUND: Escherichia coli is the most common cause of urinary tract infection (UTI). The pathogenic isolates are becoming increasingly resistant to antibiotics; with a worldwide dissemination of resistant sequence types (ST). We characterized three different uropathogenic E. coli populations...

  1. Damage-induced DNA repair processes in Escherichia coli cells

    International Nuclear Information System (INIS)

    Slezarikova, V.

    1986-01-01

    The existing knowledge is summed up of the response of Escherichia coli cells to DNA damage due to various factors including ultraviolet radiation. So far, three inducible mechanisms caused by DNA damage are known, viz., SOS induction, adaptation and thermal shock induction. Greatest attention is devoted to SOS induction. Its mechanism is described and the importance of the lexA recA proteins is shown. In addition, direct or indirect role is played by other proteins, such as the ssb protein binding the single-strand DNA sections. The results are reported of a study of induced repair processes in Escherichia coli cells repeatedly irradiated with UV radiation. A model of induction by repeated cell irradiation discovered a new role of induced proteins, i.e., the elimination of alkali-labile points in the daughter DNA synthetized on a damaged model. The nature of the alkali-labile points has so far been unclear. In the adaptation process, regulation proteins are synthetized whose production is induced by the presence of alkylation agents. In the thermal shock induction, new proteins synthetize in cells, whose function has not yet been clarified. (E.S.)

  2. Modified Vero cell induced by Bifidobacterium bifidum inhibits enterohemorrhagic Escherichia coli O157:H7 cytopathic effect

    Directory of Open Access Journals (Sweden)

    Tahamtan, Y.

    2014-11-01

    Full Text Available Enterohemorrhagic Escherichia coli (EHEC, such as E. coli O157:H7, are emerging food-borne pathogens worldwide. This micro-organism can damage the epithelial tissue of the large intestine. The cytotoxic effects can be neutralized by probiotics such as Bifidobacterium bifidum. Probiotics are viable cells that have beneficial effects on the health of the host. The preventing activity of B. bifidum against E. coli O157 was studied using a Vero cell model. Vero cell was pretreated with viable B. bifidum and incubated for either 3 h to 24 h and then collected from the cell to make modified Vero cell (MVC. Indirect antibacterial effects of B. bifidum were demonstrated by reduction of attachment of E. coli O157:H7 to MVC. The maximum reduction was resulted in pretreatment of Vero cell with B. bifidum for 24 h before infection. B. bifidum attenuated E. coli O157:H7 attachment to MVC up to 10 days of incubation. To our knowledge, MCV prevented Vero cell line injury induced by E. coli O157:H7. Therefore, B. bifidum can be used for inhibition of E. coli O157:H7 cytopathic effect (CPE in Vero cell model, even as pretreatment of the cell line.

  3. Quantification of filamentation by uropathogenic Escherichia coli during experimental bladder cell infection by using semi-automated image analysis

    DEFF Research Database (Denmark)

    Klein, Kasper; Palarasah, Yaseelan; Kolmos, Hans Jørn

    2015-01-01

    in focus-stacked microscopy images. Used in combination with a flow-chamber based in vitro cystitis model, we study the factors involved in filament formation by uropathogenic E. coli (UPEC) during infection. The influence of substratum surface, intracellular proliferation and flow media on UPEC...... rod-shaped cells. Evidence has emerged over the past decade suggesting that this morphological transformation is controlled and reversible and provides selective advantages under certain growth conditions, such as during infection in humans. In order to identify the factors which induce filamentation...... filamentation is evaluated. We show that reversible UPEC filamentation during cystitis is not dependent on intracellular infection, which previous studies have suggested. Instead, we find that filamentation can be induced by contact with surfaces, both biological and artificial. Lastly our data indicate...

  4. Effect of Helicobacter pylori Infection on Symptoms of Gastroenteritis Due to Enteropathogenic Escherichia coli in Adults

    NARCIS (Netherlands)

    Chang, Alicia Hsin-Ming; Haggerty, Thomas Dean; de Martel, Catherine; Leung, Cynthia Wai-Mun; Parsonnet, Julie

    Helicobacter pylori can cause hypochlorhydria in some hosts and predispose to diarrheal infections. We tested the hypothesis that chronic H. pylori infection increases the risk of diarrheal illness due to an acid-sensitive organism: enteropathogenic Escherichia coli (EPEC). After testing healthy

  5. Inducible error-prone repair in Escherichia coli

    International Nuclear Information System (INIS)

    Sedgwick, S.G.

    1975-01-01

    A hypothesis that ultraviolet-induced mutagenesis arises from the induction of an error-prone mode of postreplication repair that requires the exrA + recA + genotype has been tested with alkaline sucrose gradient centrifugation coupled with assays of fixation determined by loss of photoreversibility. The inhibitor of protein synthesis, chloramphenicol, added before irradiation, prevented a small amount of postreplication repair and completely eliminated mutation fixation in E. coli WP2/sub s/ uvrA. However, chloramphenicol did not affect strand joining: in uvrA bacteria allowed 20 min of growth between irradiation and antibiotic treatment; in nonmutable uvrA exrA bacteria; and in urvA tif bacteria grown at 42 0 for 70 min before irradiation. These observations indicate that an inducible product is involved in a fraction of postreplication repair and is responsible for induced mutagenesis. (auth)

  6. Enteroaggregative Escherichia coli O78:H10, the cause of an outbreak of urinary tract infection

    DEFF Research Database (Denmark)

    Olesen, Bente; Scheutz, Flemming; Andersen, Rebecca L

    2012-01-01

    to these traits and resistance profiles, are unknown. Accordingly, we extensively characterized 51 archived E. coli O78:H10 isolates (48 human isolates from seven countries, including 19 Copenhagen outbreak isolates, and 1 each of calf, avian, and unknown-source isolates), collected from 1956 through 2000. E...... by molecular methods as enteroaggregative E. coli (EAEC) (P 90% of outbreak isolates included fimH (type 1 fimbriae; ubiquitous in E. coli); fyuA, traT, and iutA (associated with extraintestinal pathogenic E. coli [ExPEC]); and sat, pic, aatA, aggR, aggA, ORF61, aaiC, aap, and ORF3......In 1991, multiresistant Escherichia coli O78:H10 strains caused an outbreak of urinary tract infections in Copenhagen, Denmark. The phylogenetic origin, clonal background, and virulence characteristics of the outbreak isolates, and their relationship to nonoutbreak O78:H10 strains according...

  7. Analysis of early-onset bloodstream infection due to Escherichia coli infection in premature babies

    OpenAIRE

    Chen, I-Lun; Huang, Hsin-Chun; Wu, Chih-Te; Ou-Yang, Mei-Chen; Chung, Mei-Yung; Chen, Chih-Cheng; Suen, Jau-Ling; Hung, Chih-Hsing

    2017-01-01

    Abstract In early-onset bacteremia among preterm neonates, Escherichia coli (E. coli) is the main pathogen and can cause a high mortality rate. Thus, the predictive factors of mortality and extended-spectrum ?-lactamase (ESBL)-producing E. coli in preterm babies with E. coli early-onset bacteremia were reported. We retrospectively reviewed preterm neonates who had E. coli bacteremia occurring within 3 days after birth between 2004 and 2015. Maternal and perinatal information were collected fr...

  8. Comparative Genomics of Escherichia coli Isolated from Skin and Soft Tissue and Other Extraintestinal Infections.

    Science.gov (United States)

    Ranjan, Amit; Shaik, Sabiha; Nandanwar, Nishant; Hussain, Arif; Tiwari, Sumeet K; Semmler, Torsten; Jadhav, Savita; Wieler, Lothar H; Alam, Munirul; Colwell, Rita R; Ahmed, Niyaz

    2017-08-15

    Escherichia coli , an intestinal Gram-negative bacterium, has been shown to be associated with a variety of diseases in addition to intestinal infections, such as urinary tract infections (UTIs), meningitis in neonates, septicemia, skin and soft tissue infections (SSTIs), and colisepticemia. Thus, for nonintestinal infections, it is categorized as extraintestinal pathogenic E. coli (ExPEC). It is also an opportunistic pathogen, causing cross infections, notably as an agent of zoonotic diseases. However, comparative genomic data providing functional and genetic coordinates for ExPEC strains associated with these different types of infections have not proven conclusive. In the study reported here, ExPEC E. coli isolated from SSTIs was characterized, including virulence and drug resistance profiles, and compared with isolates from patients suffering either pyelonephritis or septicemia. Results revealed that the majority of the isolates belonged to two pathogenic phylogroups, B2 and D. Approximately 67% of the isolates were multidrug resistant (MDR), with 85% producing extended-spectrum beta-lactamase (ESBL) and 6% producing metallo-beta-lactamase (MBL). The bla CTX-M-15 genotype was observed in at least 70% of the E. coli isolates in each category, conferring resistance to an extended range of beta-lactam antibiotics. Whole-genome sequencing and comparative genomics of the ExPEC isolates revealed that two of the four isolates from SSTIs, NA633 and NA643, belong to pandemic sequence type ST131, whereas functional characteristics of three of the ExPEC pathotypes revealed that they had equal capabilities to form biofilm and were resistant to human serum. Overall, the isolates from a variety of ExPEC infections demonstrated similar resistomes and virulomes and did not display any disease-specific functional or genetic coordinates. IMPORTANCE Infections caused by extraintestinal pathogenic E. coli (ExPEC) are of global concern as they result in significant costs to

  9. Fecal colonization with P-fimbriated Escherichia coli in newborn children and relation to development of extraintestinal E. coli infections.

    Science.gov (United States)

    Tullus, K

    1987-01-01

    The incidence of E. coli pyelonephritis before the age of one year among the children born at Danderyd Hospital during a ten year period was studied. During the study period, 4 or 5 outbreaks of E. coli pyelonephritis occurred among the children who had previously been staying in the hospital's neonatal ward. These outbreaks seemed to have been caused by nosocomial spread of and fecal colonization with certain virulent E. coli strains among the children staying in the ward during certain periods of time. The strains that were spread in the ward seemed to belong to certain pyelonephritogenic E. coli clones of the serotypes O6:K5, O4:K3 and possibly O6:K2. Although the children became fecally colonized with the strains in the neonatal ward, most fell ill some time after they had left the ward. The mean age at the development of their first pyelonephritis was 3.4 months for the boys and 6.2 months for the girls, who had been cared for in this ward. A correlation between the number of infections and the bed occupancy of the ward could be found (p less than 0.01). The risk for a child staying in the ward during an outbreak to develop pyelonephritis was about 5-10%. There was a baseline incidence rate of 0.6-0.7% during non-epidemic periods. During one of the outbreaks there was also an increased incidence rate of E. coli septicemia among the children staying in the neonatal ward. The predictive value of fecal colonization with P-fimbriated E. coli for the later development of extraintestinal E. coli infections was studied in a 2.5 year prospective study. During this study period there was a baseline incidence rate of 10-20% fecal colonization with P-fimbriated E. coli among the children staying in both the neonatal and maternity wards, interrupted only by minor peaks of colonization with such strains. Length of stay in the neonatal ward and a high bed occupancy of the neonatal ward were statistically correlated to fecal colonization with P-fimbriated E. coli strains (p

  10. Uncomplicated E Coli Urinary Tract Infection in College Women: A Follow-Up Study of E Coli Sensitivities to Commonly Prescribed Antibiotics

    Science.gov (United States)

    Ansbach, Robert K.; Dybus, Karen; Bergeson, Rachel

    2005-01-01

    Treatment of uncomplicated urinary tract infections (UTIs) has changed in the past few years with researchers advocating empiric treatment for shorter periods of time without the use of cultures. Researchers report that antibiotic resistance of Escherichia coli (E coli) to commonly prescribed antibiotics in uncomplicated UTIs has been increasing.…

  11. Epidemiological factors associated with ESBL- and non ESBL-producing E. coli causing urinary tract infection in general practice.

    Science.gov (United States)

    Hertz, Frederik Boëtius; Schønning, Kristian; Rasmussen, Steen Christian; Littauer, Pia; Knudsen, Jenny Dahl; Løbner-Olesen, Anders; Frimodt-Møller, Niels

    2016-01-01

    The purpose of the study was to evaluate how use of antibiotics precedes the presence of ESBL-producing E.coli in general practice. The authors performed a triple-case-control study where three case groups were individually compared to a single control group of uninfected individuals. Urine samples were prospectively collected and retrospective statistical analyses were done. This study included 98 cases with urinary tract infection (UTI) caused by ESBL-producing E. coli, 174 with antibiotic-resistant (non-ESBL) E. coli, 177 with susceptible E. coli and 200 with culture negative urine samples. Case groups had significantly higher use of antibiotics than the control group within 30 days before infection (p E. coli. Exposure to antibiotics was a risk factor for UTI with E. coli, while prior antibiotic usage was not an indisputable predictor for infection with ESBL-producing E.coli in general practice.

  12. Soluble products of Escherichia coli induce mitochondrial dysfunction-related sperm membrane lipid peroxidation which is prevented by lactobacilli.

    Directory of Open Access Journals (Sweden)

    Arcangelo Barbonetti

    Full Text Available Unidentified soluble factors secreted by E. coli, a frequently isolated microorganism in genitourinary infections, have been reported to inhibit mitochondrial membrane potential (ΔΨm, motility and vitality of human spermatozoa. Here we explore the mechanisms involved in the adverse impact of E. coli on sperm motility, focusing mainly on sperm mitochondrial function and possible membrane damage induced by mitochondrial-generated reactive oxygen species (ROS. Furthermore, as lactobacilli, which dominate the vaginal ecosystem of healthy women, have been shown to exert anti-oxidant protective effects on spermatozoa, we also evaluated whether soluble products from these microorganisms could protect spermatozoa against the effects of E. coli. We assessed motility (by computer-aided semen analysis, ΔΨm (with JC-1 dye by flow cytometry, mitochondrial ROS generation (with MitoSOX red dye by flow cytometry and membrane lipid-peroxidation (with the fluorophore BODIPY C11 by flow cytometry of sperm suspensions exposed to E. coli in the presence and in the absence of a combination of 3 selected strains of lactobacilli (L. brevis, L. salivarius, L. plantarum. A Transwell system was used to avoid direct contact between spermatozoa and microorganisms. Soluble products of E. coli induced ΔΨm loss, mitochondrial generation of ROS and membrane lipid-peroxidation, resulting in motility loss. Soluble factors of lactobacilli prevented membrane lipid-peroxidation of E. coli-exposed spermatozoa, thus preserving their motility. In conclusion, sperm motility loss by soluble products of E. coli reflects a mitochondrial dysfunction-related membrane lipid-peroxidation. Lactobacilli could protect spermatozoa in the presence of vaginal disorders, by preventing ROS-induced membrane damage.

  13. Antimicrobial activity of intraurethrally administered probiotic Lactobacillus casei in a murine model of Escherichia coli urinary tract infection.

    Science.gov (United States)

    Asahara, T; Nomoto, K; Watanuki, M; Yokokura, T

    2001-06-01

    The antimicrobial activity of the intraurethrally administered probiotic Lactobacillus casei strain Shirota against Escherichia coli in a murine urinary tract infection (UTI) model was examined. UTI was induced by intraurethral administration of Escherichia coli strain HU-1 (a clinical isolate from a UTI patient, positive for type 1 and P fimbriae), at a dose of 1 x 10(6) to 2 x 10(6) CFU in 20 microl of saline, into a C3H/HeN mouse bladder which had been traumatized with 0.1 N HCl followed immediately by neutralization with 0.1 N NaOH 24 h before the challenge infection. Chronic infection with the pathogen at 10(6) CFU in the urinary tract (bladder and kidneys) was maintained for more than 3 weeks after the challenge, and the number of polymorphonuclear leukocytes and myeloperoxidase activity in the urine were markedly elevated during the infection period. A single administration of L. casei Shirota at a dose of 10(8) CFU 24 h before the challenge infection dramatically inhibited E. coli growth and inflammatory responses in the urinary tract. Multiple daily treatments with L. casei Shirota during the postinfection period also showed antimicrobial activity in this UTI model. A heat-killed preparation of L. casei Shirota exerted significant antimicrobial effects not only with a single pretreatment (100 microg/mouse) but also with multiple daily treatments during the postinfection period. The other Lactobacillus strains tested, i.e., L. fermentum ATCC 14931(T), L. jensenii ATCC 25258(T), L. plantarum ATCC 14917(T), and L. reuteri JCM 1112(T), had no significant antimicrobial activity. Taken together, these results suggest that the probiotic L. casei strain Shirota is a potent therapeutic agent for UTI.

  14. Simultaneous gut colonisation and infection by ESBL-producing Escherichia coli in hospitalised patients.

    Science.gov (United States)

    Asir, Johny; Nair, Shashikala; Devi, Sheela; Prashanth, Kenchappa; Saranathan, Rajagopalan; Kanungo, Reba

    2015-01-01

    Extended spectrum betalactamase (ESBL)-producing organisms are a major cause of hospital-acquired infections. ESBL-producing Escherichia coli (E. coli) have been recovered from the hospital environment. These drug-resistant organisms have also been found to be present in humans as commensals. The present investigation intended to isolate ESBL-producing E. coli from the gut of already infected patients; to date, only a few studies have shown evidence of the gut microflora as a major source of infection. This study aimed to detect the presence of ESBL genes in E.coli that are isolated from the gut of patients who have already been infected with the same organism. A total of 70 non-repetitive faecal samples were collected from in-patients of our hospital. These in-patients were clinically diagnosed and were culture-positive for ESBL-producing E. coli either from blood, urine, or pus. Standard microbiological methods were used to detect ESBL from clinical and gut isolates. Genes coding for major betalactamase enzymes such as bla CTX-M , bla TEM, and bla SHV were investigated by polymerase chain reaction (PCR). ESBL-producing E. coli was isolated from 15 (21 per cent) faecal samples of the 70 samples that were cultured. PCR revealed that out of these 15 isolates, the bla CTX-M gene was found in 13 (86.6 per cent) isolates, the bla TEM was present in 11 (73.3 per cent) isolates, and bla SHV only in eight (53.3 per cent) isolates. All 15 clinical and gut isolates had similar phenotypic characters and eight of the 15 patients had similar pattern of genes (bla TEM, bla CTX-M, and bla SHV) in their clinical and gut isolates. Strains with multiple betalactamase genes that colonise the gut of hospitalised patients are a potential threat and it may be a potential source of infection.

  15. Decreased survival of the λ15 bacteriophage induced by UV-365 nanometers in Escherichia coli

    International Nuclear Information System (INIS)

    Luca, M.E.M. de.

    1989-01-01

    The results of our investigation showed a new effect (not yet described in the current literature) of the UV-365 nm, verified when the bacteria E. coli was irradiated with this wavelenght and then infected with bacteriophage irradiated with short UV (254 nm). In these conditions we observed a decrease in the phage survival. This phenomenon was called Decreased Survival of the Bacteriophage (DSB). We were able to show that DSB was only induced in bacteria irradiated with UV-365 nm, proficient in recombination repair and owning 4-thiouridine in their tRNA. For the induction of DSB it is necessary to promote damage in the bacteriophage through UVA and UVB. It seems that DSB and SOS are antagonistic since DSB is able to suppress the mutation induced by SOS. (author)

  16. Relative nephroprotection during Escherichia coli O157:H7 infections: association with intravenous volume expansion.

    Science.gov (United States)

    Ake, Julie A; Jelacic, Srdjan; Ciol, Marcia A; Watkins, Sandra L; Murray, Karen F; Christie, Dennis L; Klein, Eileen J; Tarr, Phillip I

    2005-06-01

    The hemolytic uremic syndrome (HUS) consists of hemolytic anemia, thrombocytopenia, and renal failure. HUS is often precipitated by gastrointestinal infection with Shiga toxin-producing Escherichia coli and is characterized by a variety of prothrombotic host abnormalities. In much of the world, E coli O157:H7 is the major cause of HUS. HUS can be categorized as either oligoanuric (which probably signifies acute tubular necrosis) or nonoligoanuric. Children with oligoanuric renal failure during HUS generally require dialysis, have more complicated courses, and are probably at increased risk for chronic sequelae than are children who experience nonoligoanuric HUS. Oligoanuric HUS should be avoided, if possible. The presentation to medical care of a child with definite or possible E coli O157:H7 infections but before HUS ensues affords a potential opportunity to ameliorate the course of the subsequent renal failure. However, it is not known whether events that occur early in E coli O157:H7 infections, particularly measures to expand circulating volume, affect the likelihood of experiencing oligoanuric HUS if renal failure develops. We attempted to assess whether pre-HUS interventions and events, especially the volume and sodium content of intravenous fluids administered early in illness, affect the risk for developing oligoanuric HUS after E coli O157:H7 infections. We performed a prospective cohort study of 29 children with HUS that was confirmed microbiologically to be caused by E coli O157:H7. Infected children were enrolled when they presented with acute bloody diarrhea or as contacts of patients who were known to be infected with E coli O157:H7, or if they had culture-confirmed infection, or if they presented with HUS. HUS was defined as hemolytic anemia (hematocrit parenteral fluid administered, were recorded and entered into analysis. Estimates of odds ratios were adjusted for possible confounding effects using logistic regression analysis. Twenty-nine children

  17. Induced clustering of Escherichia coli by acoustic fields.

    Science.gov (United States)

    Gutiérrez-Ramos, Salomé; Hoyos, Mauricio; Ruiz-Suárez, J C

    2018-03-16

    Brownian or self-propelled particles in aqueous suspensions can be trapped by acoustic fields generated by piezoelectric transducers usually at frequencies in the megahertz. The obtained confinement allows the study of rich collective behaviours like clustering or spreading dynamics in microgravity-like conditions. The acoustic field induces the levitation of self-propelled particles and provides secondary lateral forces to capture them at nodal planes. Here, we give a step forward in the field of confined active matter, reporting levitation experiments of bacterial suspensions of Escherichia coli. Clustering of living bacteria is monitored as a function of time, where different behaviours are clearly distinguished. Upon the removal of the acoustic signal, bacteria rapidly spread, impelled by their own swimming. Nevertheless, long periods of confinement result in irreversible bacteria entanglements that could act as seeds for levitating bacterial aggregates.

  18. Characteristics of Escherichia coli causing persistence or relapse of urinary tract infections

    DEFF Research Database (Denmark)

    Ejrnæs, Karen; Stegger, Marc; Reisner, Andreas

    2011-01-01

    Recurrent urinary tract infections (RUTIs) pose a major problem but little is known about characteristics of Escherichia coli associated with RUTI. This study includes E. coli from 155 women with community-acquired lower urinary tract infections (UTIs) randomized to one of three dosing regiments...... of persistence or relapse of UTI compared with three days. In vitro biofilm formation was not higher among E. coli causing persistence or relapse. The presence of agn43a(CFT073) or agn43b(CFT073) was associated with biofilm forming capacity. In conclusion, our results show potential targets for prevention...... and treatment of persistence/relapse of UTI and potential markers for selecting treatment lengths and warrant studies of these and new VFGs....

  19. Neonatal Escherichia coli Bloodstream Infections: Clinical Outcomes and Impact of Initial Antibiotic Therapy.

    Science.gov (United States)

    Bergin, Stephen P; Thaden, Joshua T; Ericson, Jessica E; Cross, Heather; Messina, Julia; Clark, Reese H; Fowler, Vance G; Benjamin, Daniel K; Hornik, Christoph P; Smith, P Brian

    2015-09-01

    Escherichia coli is a common cause of bloodstream infections (BSIs) in infants and is associated with high mortality and morbidity among survivors. The clinical significance of antibiotic resistance and timing of appropriate antimicrobial therapy in this population is poorly understood. We identified all infants with E. coli BSIs discharged from 77 neonatal intensive care units managed by the Pediatrix Medical Group in 2012. We used multivariable logistic regression to evaluate the association between 30-day mortality and ampicillin-resistant E. coli BSI, as well as the number of active empiric antimicrobial agents administered, controlling for gestational age, small-for-gestational age status, early-onset versus late-onset BSI, oxygen requirement, ventilator support and inotropic support on the day of the first positive blood culture. We identified 258 episodes of E. coli BSI, including 123 (48%) ampicillin-resistant isolates. Unadjusted 30-day mortality did not significantly differ between infants with ampicillin-resistant versus ampicillin-susceptible E. coli BSI [11 of 123 (9%) vs. 7 of 135 (5%); P = 0.33; adjusted odds ratio = 1.37 (95% confidence interval: 0.39, 4.77)]. Among ampicillin-resistant E. coli BSIs, 30-day mortality was not significantly lower for infants treated with at least one empiric antimicrobial active against ampicillin-resistant E. coli versus infants receiving no active empiric agent [adjusted odds ratio = 1.50 (0.07, 33.6)]. In this population of infants with E. coli BSI, ampicillin resistance was not associated with significantly increased mortality. Among the subset of infants with ampicillin-resistant E. coli, appropriate empirical antibiotic therapy was not associated with lower mortality.

  20. Problem-Solving Test: RNA and Protein Synthesis in Bacteriophage-Infected "E. coli" Cells

    Science.gov (United States)

    Szeberenyi, Jozsef

    2008-01-01

    The classic experiment presented in this problem-solving test was designed to identify the template molecules of translation by analyzing the synthesis of phage proteins in "Escherichia coli" cells infected with bacteriophage T4. The work described in this test led to one of the most seminal discoveries of early molecular biology: it dealt a…

  1. Urinary tract infections of Escherichia coli strains of chaperone-usher system.

    Science.gov (United States)

    Zalewska-Piatek, Beata M

    2011-01-01

    Urinary tract infections are a very serious health and economic problem affecting millions of people each year worldwide. The most common etiologic agent of this type of bacterial infections, involving the upper and lower urinary tract, are E. coli strains representing approximately 80% of cases. Uropathogenic E. coli strains produce several urovirulence factors which can be divided into two main types, surface virulence factors and exported virulence factors. Surface-exposed structures include mainly extracellular adhesive organelles such as fimbriae/pili necessary in adhesion, invasion, biofilm formation and cytokine induction. Among the surface-exposed polymeric adhesive structures there are three most invasive groups, type 1 pili, type P pili and Dr family of adhesins which are bioassembled via the conserved, among Gram-negative bacteria, chaperone-usher secretion system. Type 1 and P-piliated E. coli cause cystitis and pyelonephritis. The Dr family of adhesins recognizing DAF receptor is responsible for cystitis, pyelonephritis (especially in pregnant women) and diarrhoea (in infants). In addition, Dr-positive E. coli strains carry the risk of recurrent urinary tract infections. Pyelonephritis in pregnant women leads to a series of complications such as bacteremia, urosepsis, acute respiratory distress syndrome and even death. In the era of increasing drug resistance of bacteria, the development of vaccines, drugs termed pilicides and inhibitors of adhesion may be a promising tool in the fight against urogenital infections.

  2. Endonuclease IV of Escherichia coli is induced by paraquat

    International Nuclear Information System (INIS)

    Chan, E.; Weiss, B.

    1987-01-01

    The addition of paraquat (methyl viologen) to a growing culture of Escherichia coli K-12 led within 1 hr to a 10- to 20-fold increase in the level of endonuclease IV, a DNase for apurinic/apyrimidinic sites. The induction was blocked by chloramphenicol. Increases of 3-fold or more were also seen with plumbagin, menadione, and phenazine methosulfate. H 2 O 2 produced no more than a 2-fold increase in endonuclease IV activity. The following agents had no significant effect: streptonigrin, nitrofurantoin, tert-butyl hydroperoxide, γ rays, 260-nm UV radiation, methyl methanesulfonate, mitomycin C, and ascorbate. Paraquat, plumbagin, menadione, and phenazine methosulfate are known to generate superoxide radical anions via redox cycling in vivo. A mutant lacking superoxide dismutase was unusually sensitive to induction by paraquat. In addition, endonuclease IV could be induced by merely growing the mutant in pure O 2 . The levels of endonuclease IV in uninduced or paraquat-treated cells were unaffected by mutations of oxyR, a H 2 O 2 -inducible gene that governs an oxidative-stress regulon. The results indicate that endonuclease IV is an inducible DNA-repair enzyme and that its induction can be mediated via the production of superoxide radicals

  3. Endonuclease IV of Escherichia coli is induced by paraquat

    Energy Technology Data Exchange (ETDEWEB)

    Chan, E.; Weiss, B.

    1987-05-01

    The addition of paraquat (methyl viologen) to a growing culture of Escherichia coli K-12 led within 1 hr to a 10- to 20-fold increase in the level of endonuclease IV, a DNase for apurinic/apyrimidinic sites. The induction was blocked by chloramphenicol. Increases of 3-fold or more were also seen with plumbagin, menadione, and phenazine methosulfate. H/sub 2/O/sub 2/ produced no more than a 2-fold increase in endonuclease IV activity. The following agents had no significant effect: streptonigrin, nitrofurantoin, tert-butyl hydroperoxide, ..gamma.. rays, 260-nm UV radiation, methyl methanesulfonate, mitomycin C, and ascorbate. Paraquat, plumbagin, menadione, and phenazine methosulfate are known to generate superoxide radical anions via redox cycling in vivo. A mutant lacking superoxide dismutase was unusually sensitive to induction by paraquat. In addition, endonuclease IV could be induced by merely growing the mutant in pure O/sub 2/. The levels of endonuclease IV in uninduced or paraquat-treated cells were unaffected by mutations of oxyR, a H/sub 2/O/sub 2/-inducible gene that governs an oxidative-stress regulon. The results indicate that endonuclease IV is an inducible DNA-repair enzyme and that its induction can be mediated via the production of superoxide radicals.

  4. Non-Escherichia coli versus Escherichia coli community-acquired urinary tract infections in children hospitalized in a tertiary center: relative frequency, risk factors, antimicrobial resistance and outcome.

    Science.gov (United States)

    Marcus, Nir; Ashkenazi, Shai; Yaari, Arnon; Samra, Zmira; Livni, Gilat

    2005-07-01

    Currently hospitalization for children with urinary tract infections (UTIs) is reserved for severe or complicated cases. Changes may have taken place in the characteristics and causative uropathogens of hospital-treated community-acquired UTI. To study children hospitalized in a tertiary center with community-acquired UTI, compare Escherichia coli and non-E. coli UTI, define predictors for non-E. coli UTI and elucidate the appropriate therapeutic approach. A prospective clinical and laboratory study from 2001 through 2002 in a tertiary pediatric medical center. Patients were divided by results of the urine culture into E. coli and non-E. coli UTI groups, which were compared. Of 175 episodes of culture-proved UTI, 70 (40%) were caused by non-E. coli pathogens. Non-E. coli UTI was more commonly found in children who were male (P = 0.005), who had underlying renal abnormalities (P = 0.0085) and who had received antibiotic therapy in the prior month (P = 0.0009). Non-E. coli uropathogens were often resistant to antibiotics usually recommended for initial therapy for UTI, including cephalosporins and aminoglycosides; 19% were initially treated with inappropriate empiric intravenous antibiotics (compared with 2% for E. coli UTI, P = 0.0001), with a longer hospitalization. Current treatment routines are often inappropriate for hospitalized children with non-E. coli UTI, which is relatively common in this population. The defined risk factors associated with non-E. coli UTIs and its antimicrobial resistance patterns should be considered to improve empiric antibiotic therapy for these infections.

  5. Pathogenesis of Streptococcus infantarius subspecies coli Isolated from Sea Otters with Infective Endocarditis.

    Science.gov (United States)

    Counihan, Katrina L; Gill, Verena A; Miller, Melissa A; Burek-Huntington, Kathleen A; LeFebvre, Rance B; Byrne, Barbara A

    2015-06-01

    The Gram positive bacterial coccus Streptococcus infantarius subspecies coli is increasingly linked with development of fatal vegetative infective endocarditis and septicemia in humans, sea otters (Enhydra lutris) and other animals. However, the pathogenesis of these infections is poorly understood. Using S. infantarius subsp. coli strains isolated from sea otters with infective endocarditis, this study evaluated adherence and invasion of epithelial and endothelial cells, adherence to extracellular matrix components, and macrophage survival. Significant adherence to endothelial-derived cells was observed for 62% of isolates, 24% adhered to epithelial cell lines, and 95% invaded one or both cell types in vitro. The importance of the hyaluronic acid capsule in host cell adherence and invasion was also evaluated. Capsule removal significantly reduced epithelial adherence and invasion for most S. infantarius subsp. coli isolates, suggesting that the capsule facilitates attachment to and invasion of epithelium. Enzyme-linked immunosorbent assay testing revealed that all isolates adhered significantly to the extracellular matrix components collagen IV, fibronectin, laminin and hyaluronic acid. Finally, significant bacterial survival following phagocytosis by macrophages was apparent for 81% of isolates at one or more time points. Taken collectively these findings indicate that S. infantarius subsp. coli has multiple pathogenic properties that may be important to host colonization, invasion and disease. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Endemic and Epidemic Lineages of Escherichia coli that Cause Urinary Tract Infections

    Science.gov (United States)

    Tabor, Helen; Tellis, Patricia; Vincent, Caroline; Tellier, Pierre-Paul

    2008-01-01

    Women with urinary tract infections (UTIs) in California, USA (1999–2001), were infected with closely related or indistinguishable strains of Escherichia coli (clonal groups), which suggests point source dissemination. We compared strains of UTI-causing E. coli in California with strains causing such infections in Montréal, Québec, Canada. Urine specimens from women with community-acquired UTIs in Montréal (2006) were cultured for E. coli. Isolates that caused 256 consecutive episodes of UTI were characterized by antimicrobial drug susceptibility profile, enterobacterial repetitive intergenic consensus 2 PCR, serotyping, XbaI and NotI pulsed-field gel electrophoresis, multilocus sequence typing, and phylogenetic typing. We confirmed the presence of drug-resistant, genetically related, and temporally clustered E. coli clonal groups that caused community-acquired UTIs in unrelated women in 2 locations and 2 different times. Two clonal groups were identified in both locations. Epidemic transmission followed by endemic transmission of UTI-causing clonal groups may explain these clusters of UTI cases. PMID:18826822

  7. Escherichia coli O157:H7 induces stronger plant immunity than Salmonella enterica Typhimurium SL1344.

    Science.gov (United States)

    Roy, Debanjana; Panchal, Shweta; Rosa, Bruce A; Melotto, Maeli

    2013-04-01

    Consumption of fresh produce contaminated with bacterial human pathogens has resulted in various, sometimes deadly, disease outbreaks. In this study, we assessed plant defense responses induced by the fully pathogenic bacteria Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium SL1344 in both Arabidopsis thaliana and lettuce (Lactuca sativa). Unlike SL1344, O157:H7 induced strong plant immunity at both pre-invasion and post-invasion steps of infection. For instance, O157:H7 triggered stomatal closure even under high relative humidity, an environmental condition that generally weakens plant defenses against bacteria in the field and laboratory conditions. SL1344 instead induced a transient stomatal immunity. We also observed that PR1 gene expression was significantly higher in Arabidopsis leaves infected with O157:H7 compared with SL1344. These results suggest that plants may recognize and respond to some human pathogens more effectively than others. Furthermore, stomatal immunity can diminish the penetration of human pathogens through the leaf epidermis, resulting in low bacterial titers in the plant apoplast and suggesting that additional control measures can be employed to prevent food contamination. The understanding of how plant responses can diminish bacterial contamination is paramount in preventing outbreaks and improving the safety of food supplies.

  8. Ciprofloxacin causes persister formation by inducing the TisB toxin in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Tobias Dörr

    2010-02-01

    Full Text Available Bacteria induce stress responses that protect the cell from lethal factors such as DNA-damaging agents. Bacterial populations also form persisters, dormant cells that are highly tolerant to antibiotics and play an important role in recalcitrance of biofilm infections. Stress response and dormancy appear to represent alternative strategies of cell survival. The mechanism of persister formation is unknown, but isolated persisters show increased levels of toxin/antitoxin (TA transcripts. We have found previously that one or more components of the SOS response induce persister formation after exposure to a DNA-damaging antibiotic. The SOS response induces several TA genes in Escherichia coli. Here, we show that a knockout of a particular SOS-TA locus, tisAB/istR, had a sharply decreased level of persisters tolerant to ciprofloxacin, an antibiotic that causes DNA damage. Step-wise administration of ciprofloxacin induced persister formation in a tisAB-dependent manner, and cells producing TisB toxin were tolerant to multiple antibiotics. TisB is a membrane peptide that was shown to decrease proton motive force and ATP levels, consistent with its role in forming dormant cells. These results suggest that a DNA damage-induced toxin controls production of multidrug tolerant cells and thus provide a model of persister formation.

  9. Polyglycolic acid (Dexon) sutures in Escherichia coli infected urine

    DEFF Research Database (Denmark)

    Hovendal, C P; Schwartz, W

    1979-01-01

    The tensile strength, knot strength and stretch of polyglycolic acid (Dexon) was studied after emersion in physiological saline, sterile urine and infected urine. Tests were made each day under controlled conditions over a 10 day period. The results are compared with those of other earlier studie...

  10. Lactobacillus rhamnosus GR-1 Ameliorates Escherichia coli-Induced Inflammation and Cell Damage via Attenuation of ASC-Independent NLRP3 Inflammasome Activation.

    Science.gov (United States)

    Wu, Qiong; Liu, Ming-Chao; Yang, Jun; Wang, Jiu-Feng; Zhu, Yao-Hong

    2016-02-15

    Escherichia coli is a major environmental pathogen causing bovine mastitis, which leads to mammary tissue damage and cell death. We explored the effects of the probiotic Lactobacillus rhamnosus GR-1 on ameliorating E. coli-induced inflammation and cell damage in primary bovine mammary epithelial cells (BMECs). Increased Toll-like receptor 4 (TLR4), NOD1, and NOD2 mRNA expression was observed following E. coli challenge, but this increase was attenuated by L. rhamnosus GR-1 pretreatment. Immunofluorescence and Western blot analyses revealed that L. rhamnosus GR-1 pretreatment decreased the E. coli-induced increases in the expression of the NOD-like receptor family member pyrin domain-containing protein 3 (NLRP3) and the serine protease caspase 1. However, expression of the adaptor protein apoptosis-associated speck-like protein (ASC, encoded by the Pycard gene) was decreased during E. coli infection, even with L. rhamnosus GR-1 pretreatment. Pretreatment with L. rhamnosus GR-1 counteracted the E. coli-induced increases in interleukin-1β (IL-1β), -6, -8, and -18 and tumor necrosis factor alpha mRNA expression but upregulated IL-10 mRNA expression. Our data indicate that L. rhamnosus GR-1 reduces the adhesion of E. coli to BMECs, subsequently ameliorating E. coli-induced disruption of cellular morphology and ultrastructure and limiting detrimental inflammatory responses, partly via promoting TLR2 and NOD1 synergism and attenuating ASC-independent NLRP3 inflammasome activation. Although the residual pathogenic activity of L. rhamnosus, the dosage regimen, and the means of probiotic supplementation in cattle remain undefined, our data enhance our understanding of the mechanism of action of this candidate probiotic, allowing for development of specific probiotic-based therapies and strategies for preventing pathogenic infection of the bovine mammary gland. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  11. Escherichia coli and urinary tract infections: the role of poultry-meat.

    Science.gov (United States)

    Manges, A R

    2016-02-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) is the most common cause of community-acquired and hospital-acquired extraintestinal infections. The hypothesis that human ExPEC may have a food animal reservoir has been a topic of investigation by multiple groups around the world. Experimental studies showing the shared pathogenic potential of human ExPEC and avian pathogenic E. coli suggest that these extraintestinal E. coli may be derived from the same bacterial lineages or share common evolutionary roots. The consistent observation of specific human ExPEC lineages in poultry or poultry products, and rarely in other meat commodities, supports the hypothesis that there may be a poultry reservoir for human ExPEC. The time lag between human ExPEC acquisition (in the intestine) and infection is the fundamental challenge facing studies attempting to attribute ExPEC transmission to poultry or other environmental sources. Even whole genome sequencing efforts to address attribution will struggle with defining meaningful genetic relationships outside of a discrete food-borne outbreak setting. However, if even a fraction of all human ExPEC infections, especially antimicrobial-resistant ExPEC infections, is attributable to the introduction of multidrug-resistant ExPEC lineages through contaminated food product(s), the relevance to public health, food animal production and food safety will be significant. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  12. Detection & characterization of necrotoxin producing Escherichia coli (NTEC) from patients with urinary tract infection (UTI).

    Science.gov (United States)

    Rahman, Helina; Deka, Manab

    2014-04-01

    Urinary tract infections (UTI) are a serious health problem affecting millions of people each year. Although appreciable work on various aspects of UTI including aetiology per se has been done, information on the emerging pathogens like necrotoxigenic Escherichia coli (NTEC) is largely lacking in India. In the present study E. coli isolates from patients with urinary tract infection from northeastern India were investigated for detection and characterization of NTEC. E. coli isolated and identified from urine samples of patients with UTI were serotyped. Antibiogram was determined by disc diffusion test. Plasmid profile was also determined. Virulence genes of NTEC (cnf1, cnf2, pap, aer, sfa, hly, afa) were detected by PCR assay. E.coli isolates carrying cnf gene (s) were identified as NTEC. A total of 550 E. coli were isolated and tested for the presence of cnf genes. Of these, 84 (15.27%) belonged to NTEC. The cnf1 gene was present in 52 (61.9%) isolates, cnf2 in 23 (27.4%) and 9 (10.7%) carried both cnf1 and cnf2 genes. All the NTEC strains were found to harbour the pap and aer genes. Serogroup O4 was found to be the most common among the 12 serogroups identified amongst the NTEC isolates. Majority of the isolates (96.4%) were sensitive to furazolidone and were highly resistant to ampicillin. NTEC were found to harbour different numbers of plasmids (1 to 7). No association was observed between the number of plasmids and the antibiotic resistance of the isolates. The results of the present study showed that about 15 per cent of E. coli isolates associated with UTI belonged to NTEC. More studies need to be done from other parts of the country.

  13. Lactobacillus rhamnosus GG supernatant enhance neonatal resistance to systemic Escherichia coli K1 infection by accelerating development of intestinal defense

    OpenAIRE

    Xiaolong He; Qing Zeng; Santhosh Puthiyakunnon; Zhijie Zeng; Weijun Yang; Jiawen Qiu; Lei Du; Swapna Boddu; Tongwei Wu; Danxian Cai; Sheng-He Huang; Hong Cao

    2017-01-01

    The objective of this study was to determine whether Lactobacillus rhamnosus GG culture supernatant (LCS) has a preventive effect against gut-derived systemic neonatal Escherichia coli (E. coli) K1 infection. The preventive effects were evaluated in human colonic carcinoma cell line Caco-2 and neonatal rat models. Our in vitro results showed that LCS could block adhesion, invasion and translocation of E. coli K1 to Caco-2 monolayer via up-regulating mucin production and maintaining intestinal...

  14. Protection against Escherichia coli K1 infection in newborn rats by antibody to K1 capsular polysaccharide antigen.

    OpenAIRE

    Bortolussi, R; Ferrier, P

    1980-01-01

    The protective value of antibody to the K1 capsular polysaccharide antigen of Escherichia coli was investigated in a newborn rat model of E. coli K1 infection. Pregnant rats were immunized intravenously with E. coli, and the agglutinating titer to meningococcal group B polysaccharide, which is identical to K1 polysaccharide, was measured in the serum of rats and their offspring. Convalescent serum from rat mothers showed an increased antibody titer in animals injected twice but not once with ...

  15. Supplementation with Lactobacillus paracasei or Pediococcus pentosaceus does not prevent diarrhoea in neonatal pigs infected with Escherichia coli F18

    DEFF Research Database (Denmark)

    Andersen, Anders Daniel; Cilieborg, Malene Skovsted; Lauridsen, Charlotte

    2017-01-01

    Infectious diarrhoea is a worldwide problem in newborns. Optimal bacterial colonisation may enhance gut maturation and protect against pathogenic bacteria after birth. We hypothesised that lactic acid bacteria (LAB) administration prevents pathogen-induced diarrhoea in formula-fed newborns. Newbo....... coli-induced diarrhoea in sensitive newborn pigs. In vulnerable newborns there may be a delicate balance among bacterial composition and load, diet and the host. Caution may be required when administering LAB to compromised newborns suffering from enteric infections....... caesarean-delivered, colostrum-deprived term piglets on parenteral nutrition for the first 15 h, were used as models for sensitive newborn infants. A commercially available probiotic strain, Lactobacillus paracasei F19 (LAP, 2·6x108 colony-forming units (CFU)/kg per d) and a novel LAB isolate, Pediococcus...... with decreased activities in most cases after F18 and LAB inoculation. Bacterial density in colon mucosa increased after F18 inoculation (PE...

  16. Signs Indicating Imminent Death in Escherichia coli-Infected Broilers.

    Science.gov (United States)

    Matthijs, M G R; Nieuwenhuis, J F; Dwars, R M

    2017-09-01

    Broilers were observed during 9 days for clinical signs after intratracheal inoculation at 8 days of age with 10 7 E. coli 506. It was determined if these signs were predictive for imminent death. Hourly observations were made daily from a distance of 1-2 m and nightly by camera observation, with respect to the following parameters: level of attention, locomotory activity, posture and appearance, interaction, and impairment of respiration. For deviations of the normal state for these five parameters (i.e., typical clinical signs of disease), scores were defined in up to four classes. The periods of time elapsing from attaining a score for the first time to death were registered per bird for each score for each parameter. Of 114 birds, 85 did not present typical signs of illness as described, and 29 presented the following clinical history: 25 died after presenting signs of illness, 2 died without previous signs, 1 fell ill but survived, and 1 fell ill and recovered. Extended clinical examination was performed in birds presenting clinical signs; temperature, heart rate, respiratory rate, and subcutaneous capillary refill time were measured. The level of attention, and posture and appearance were affected most often in ill birds; 25% of these birds died within 5 and 4 hr, respectively; 50% died within 12 hr; and 75% died within 20 and 19 hr, respectively. Any of these typical signs of illness visible from 1-2 m indicated imminent death, with 75% of the birds dying within 20 hr. Measurements resulting from extended clinical examination proved of lesser predictive value. From these observations, a protocol for intervention to prevent animal suffering may be designed.

  17. Prevalence and sustainable control of Balantidium coli infection in pigs of Ranchi, Jahrkahnd, India

    Directory of Open Access Journals (Sweden)

    R K Bauri

    2012-04-01

    Full Text Available Pigs had a higher degree of gastrointestinal protozoa infection 93 out of 100 faecal samples. Balantidium coli infected pigs were controlled effectively by oxytetracycline (100% on 3rd day of observation and Metronidazole +Furazolidone combination (100% on 5th day of observation. Initially B. coli infected pigs had decreased haemoglobin, pack cell volume and total erythrocyte count values, but these pigs returned towards normal ranges after 7th day of observation. The differential leukocyte count values of B. coli infected pigs showed decreased values of neutrophils, and lymphocytes, and increased eosinophils values come towards normal range on 7th day of observation. The average body weight gain in oxytetracycline and metronidazole + furazolidone combination treated Tampworth & Desi piglets showed higher viz.35.25 ± 1.64 kg and 28.08 ± 1.75 kg of body weight respectively than untreated infected control piglets (15.75 ± 2.39. The average body weight gain in Oxytetracycline and metronidazole + furazolidone combination treated desi piglets were higher body weight viz. 36.67±1.07 kg and 32.50±0.96 kg respectively than untreated infected control piglets (22.00±0.88 kg. In both the treatment group, the group treated with Oxytetracycline had significantly higher body weight gain 35.25 ± 1.64 kg and 36.67±1.07 kg in both T & D and desi piglets respectively than metronidazole +furazolidone combination treated T & D and desi piglets (28.08 ± 1.75 kg, 32.50±0.96 kg respectively. The observation on different hematological parameters during B. coli infection and their treatment indicated that the harm caused by B. coli in pigs could be reduced to a greater extent by suitable therapeutic management. Application of suitable control packages were found to be very encouraging for maintaining optimum health and economical pig production. Oxytetracycline drugs showed higher efficacy than metronidazole + furazolidone combination and it show significantly

  18. Recovery of the accumulation ability of thiomethyl-β-galactoside in Escherichia coli after bacteriophage T4 infection

    International Nuclear Information System (INIS)

    Saijo, N.; Okamoto, K.

    1976-01-01

    Effects of uv-irradiated and unirradiated T4 phage infection on the β-galactoside accumulation ability in Escherichia coli have been examined by the use of 14 C-labeled thiomethyl-β-galactoside (TMG). Under conditions where a synchronous adsorption of phage takes place, the cellular ability for TMG accumulation is found to be largely inhibited immediately after phage adsorption but it recovers with time to a new level, which is dependent on the multiplicity of infection. When cells are infected with uv-irradiated T4 at the same multiplicity as that of unirradiated phage, the cellular accumulation ability is more severely inhibited and there is no recovery from the inhibition. The recovery process in T4-infected cells is mostly sensitive to puromycin. These results suggest that the initial inhibition of the TMG accumulation ability is probably caused by the adsorption of phage coats, and the subsequent restoration occurs through the action of a phage-directed protein(s). In the recovery process, no new transport system appears to be involved. The restored ability of TMG accumulation is resistant to the action of superinfecting uv phage. However, different mechanisms appear to be operating in T4-infected cells for the establishment of resistance to ghosts and for the recovery from the phage coat-induced inhibition

  19. Expression of ultraviolet-induced restriction alleviation in Escherichia coli K-12

    International Nuclear Information System (INIS)

    Thoms, B.; Wackernagel, W.

    1983-01-01

    Ultraviolet-induced restriction alleviation is an SOS function which partially relieves the K-12-specific DNA restriction in Escherichia coli. Restriction alleviation is determined by observing elevated survival of unmodified phage lambda in cells irradiated with ultraviolet prior to infection. The authors demonstrate that restriction of lambda is also relieved when log-phase cells are irradiated as late as 50 min after adsorption of lambda. At this time more than 60% of the lambda DNA is already released as acid-soluble material from the cells. Experiments involving reextraction of lambda DNA from infected cells and a mild detergent treatment removing adsorbed phages from the cellular surface showed that only a small specific fraction of all lambda infections is destined to escape restriction due to restriction alleviation. This fraction (10-20%) has a retarded mode of DNA injection (60 min or longer) after adsorption which allows the expression of the restriction alleviation function before the phage DNA is exposed to restriction endonucleases. This behaviour of a fraction of lambda phages explains why the SOS function restriction alleviation could initially be discovered. The authors show that the retarded mode of DNA injection is not required for another SOS function acting on lambda DNA, the increased repair of ultraviolet-irradiated DNA (Weigle reactivation). (Auth.)

  20. Epidemiological factors associated with ESBL- and non ESBL-producing E. coli causing urinary tract infection in general practice

    DEFF Research Database (Denmark)

    Hertz, Frederik Boetius; Schønning, Kristian; Rasmussen, Steen Christian

    2016-01-01

    were prospectively collected and retrospective statistical analyses were done. This study included 98 cases with urinary tract infection (UTI) caused by ESBL-producing E. coli, 174 with antibiotic-resistant (non-ESBL) E. coli, 177 with susceptible E. coli and 200 with culture negative urine samples....... Case groups had significantly higher use of antibiotics than the control group within 30 days before infection (p UTI by ESBL......-producing E. coli. Exposure to antibiotics was a risk factor for UTI with E. coli, while prior antibiotic usage was not an indisputable predictor for infection with ESBL-producing E.coli in general practice....

  1. Resistance trends and risk factors of extended spectrum β-lactamases in Escherichia coli infections in Aleppo, Syria.

    Science.gov (United States)

    Al-Assil, Bodour; Mahfoud, Maysa; Hamzeh, Abdul Rezzak

    2013-07-01

    Recently, there has been a notable surge in urinary tract infections (UTIs) by extended spectrum β-lactamase (ESBL)-producing Escherichia coli, which considerably limits treatment options. This study aimed to determine prevalence, phenotypic patterns, and ESBL-production status of E coli in isolates from UTI patients along with uncovering locally relevant risk factors for contracting ESBL-producing E coli infections. One hundred four nonrepetitive urine samples were collected from 3 major hospitals in Aleppo, Syria. Antibiotic susceptibility and ESBL production were studied by disc diffusion and double disk synergy tests according to Clinical Laboratory Standards Institute guidelines. Epidemiologic analysis was done using χ(2) and multivariate logistic regression tests. This study revealed high prevalence of multidrug-resistant (MDR) E coli reaching 63%, whereas ESBL-producing E coli exceeded 52%. The latter exhibited alarmingly elevated levels of coresistance to non-β-lactam antibiotics leading to vast increase in MDR rates in comparison with non-ESBL-producing E coli (83.6% vs 12.2%, respectively). We found previous exposure to third-generation cephalosporins and fluoroquinolones to be a significant risk factor for ESBL-producing E coli infections, in addition to other known factors such as hospitalization and catheterization. Tigecycline and carbapenems demonstrated near perfect efficacy against tested E coli, so they rank high among treatment options. Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  2. Enterohemorrhagic Escherichia coli senses low biotin status in the large intestine for colonization and infection

    Science.gov (United States)

    Yang, Bin; Feng, Lu; Wang, Fang; Wang, Lei

    2015-01-01

    Enterohemorrhagic Escherichia coli (EHEC) is an important foodborne pathogen that infects humans by colonizing the large intestine. Here we identify a virulence-regulating pathway in which the biotin protein ligase BirA signals to the global regulator Fur, which in turn activates LEE (locus of enterocyte effacement) genes to promote EHEC adherence in the low-biotin large intestine. LEE genes are repressed in the high-biotin small intestine, thus preventing adherence and ensuring selective colonization of the large intestine. The presence of this pathway in all nine EHEC serotypes tested indicates that it is an important evolutionary strategy for EHEC. The pathway is incomplete in closely related small-intestinal enteropathogenic E. coli due to the lack of the Fur response to BirA. Mice fed with a biotin-rich diet show significantly reduced EHEC adherence, indicating that biotin might be useful to prevent EHEC infection in humans. PMID:25791315

  3. Mucin2 is Required for Probiotic Agents-Mediated Blocking Effects on Meningitic E. coli-Induced Pathogenicities.

    Science.gov (United States)

    Yu, Jing-Yi; He, Xiao-Long; Puthiyakunnon, Santhosh; Peng, Liang; Li, Yan; Wu, Li-Sha; Peng, Wen-Ling; Zhang, Ya; Gao, Jie; Zhang, Yao-Yuan; Boddu, Swapna; Long, Min; Cao, Hong; Huang, Sheng-He

    2015-10-01

    Mucin2 (MUC2), an important regulatory factor in the immune system, plays an important role in the host defense system against bacterial translocation. Probiotics known to regulate MUC2 gene expression have been widely studied, but the interactions among probiotic, pathogens, and mucin gene are still not fully understood. The aim of this study was to investigate the role of MUC2 in blocking effects of probiotics on meningitic E. coli-induced pathogenicities. In this study, live combined probiotic tablets containing living Bifidobacterium, Lactobacillus bulgaricus, and Streptococcus thermophilus were used. MUC2 expression was knocked down in Caco-2 cells by RNA interference. 5-Aza-2'-deoxycytidine (5-Aza-CdR), which enhances mucin-promoted probiotic effects through inducing production of Sadenosyl- L-methionine (SAMe), was used to up-regulate MUC2 expression in Caco-2 cells. The adhesion to and invasion of meningitic E. coli were detected by competition assays. Our studies showed that probiotic agents could block E. coli-caused intestinal colonization, bacteremia, and meningitis in a neonatal sepsis and meningitis rat model. MUC2 gene expression in the neonatal rats given probiotic agents was obviously higher than that of the infected and uninfected control groups without probiotic treatment. The prohibitive effects of probiotic agents on MUC2-knockdown Caco-2 cells infected with E44 were significantly reduced compared with nontransfected Caco-2 cells. Moreover, the results also showed that 5- Aza-CdR, a drug enhancing the production of SAMe that is a protective agent of probiotics, was able to significantly suppress adhesion and invasion of E44 to Caco-2 cells by upregulation of MUC2 expression. Taken together, our data suggest that probiotic agents can efficiently block meningitic E. coli-induced pathogenicities in a manner dependent on MUC2.

  4. The treatment of irradiated mice with polymicrobial infection caused by Bacteroides fragilis and Escherichia coli

    International Nuclear Information System (INIS)

    Brook, Itzhak; Ledney, G.D.

    1994-01-01

    The effects on the faecal flora and the efficacies of various antibiotic regimens administered as treatment for a mixed infection caused by Bacteroides fragilis and Escherichia coli in the irradiated host were investigated in a subcutaneous abscess model with C 3 H/HeN mice which had been exposed to 60 Co. The regimens used included imipenem, ofloxacin, metronidazole and the combination of ofloxacin and metronidazole. (author)

  5. The treatment of irradiated mice with polymicrobial infection caused by Bacteroides fragilis and Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Brook, Itzhak (Naval Medical Research Inst., Bethesda, MD (United States)); Ledney, G.D. (Armed Forces Radiobiology Research Inst., Bethesda, MD (United States))

    1994-02-01

    The effects on the faecal flora and the efficacies of various antibiotic regimens administered as treatment for a mixed infection caused by Bacteroides fragilis and Escherichia coli in the irradiated host were investigated in a subcutaneous abscess model with C[sub 3]H/HeN mice which had been exposed to [sup 60]Co. The regimens used included imipenem, ofloxacin, metronidazole and the combination of ofloxacin and metronidazole. (author).

  6. Outbreak of E. coli 0157:H7 Infections Associated With Ready-To ...

    African Journals Online (AJOL)

    Microbiota of retail ready-to-eat cashew nuts was investigated due to outbreak of E. coli 0157:H7 infections during 2006 and 2007 respectively. Moisture content: 3.7 -4.3 and 3.2 - 5.4 respectively. Mesophillic bacteria: 4 - 19 x 10>sup>4cfu/g; Staphylococcus aureus: 2 - 4 x 104 cfu/g; Coliform count: 2 - 3.0 x 104 cfu/g; ...

  7. 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 ...

  8. Breaks induced in the deoxyribonucleic acid of aerosolized Escherichia coli by ozonized cyclohexene.

    Science.gov (United States)

    De Mik, G; De Groot, I

    1978-01-01

    The inactivation of aerosolized Escherichia coli by ozone, cyclohexene, and ozonized cyclohexene was studied. The parameters for damage were loss of reproduction and introduction of breaks in the deoxyribonucleic acid (DNA). Aerosolization of E. coli in clean air at 80 percent relative humidity or in air containing either ozone or cyclohexene hardly affected survival; however, some breaks per DNA molecule were induced, as shown by sucrose gradient sedimentation of the DNA. Aerosolization of E. coli in air containing ozonized cyclohexene at 80 percent relative humidity decreased the survival by a factor of 10(3) or more after 1 h of exposure and induced many breaks in the DNA. PMID:341811

  9. Microbiological diagnosis of infections caused by Campylobacter jejuni and Campylobacter coli in humans

    Directory of Open Access Journals (Sweden)

    Natalia Rokosz

    2014-01-01

    Full Text Available Campylobacter jejuni and Campylobacter coli are Gram-negative, microaerophilic bacteria which are worldwide in distribution, causing a zoonotic disease in humans called campylobacteriosis. These infections are mainly caused by eating contaminated food products, most often improperly prepared poultry meat. Campylobacteriosis usually takes the form of gastroenteritis, or inflammation of the intestines, and the characteristic symptoms are watery-mucous diarrhea often with the presence of blood in stool, nausea, vomiting, abdominal pain and fever. The epidemiological data suggest that in Europe, as well as in North America, bacteria of the genus Campylobacter, especially C. jejuni and C. coli, are the most commonly isolated pathogens in infections of the gastrointestinal tract in humans. Epidemiological data indicate that these organisms are a much more common cause of acute diarrhea, mostly in young children, than Salmonella and Yersinia. The lack of specific symptoms makes the diagnosis of campylobacteriosis necessary to carry out specialized microbiological diagnostics. Because so far these studies are performed in our country only in a few laboratories, the overwhelming number of cases of campylobacteriosis are not recorded in Polish epidemiological statistics. The purpose of this paper is to discuss issues related to the microbiological diagnosis of infections caused by C. jejuni and C. coli. It also describes the basic epidemiological and clinical data, as well as current treatment of campylobacteriosis.

  10. Effects of burn with and without Escherichia coli infection in rats on intestinal vs. splenic T-cell responses.

    Science.gov (United States)

    Ravindranath, T; Al-Ghoul, W; Namak, S; Fazal, N; Durazo-Arvizu, R; Choudhry, M; Sayeed, M M

    2001-12-01

    To evaluate the effect of burn injury with and without an Escherichia coliseptic complication on T-cell proliferation, interleukin-2 production, and Ca(2+) signaling responses in intestinal Peyer's patch and splenic T cells. Prospective, randomized, sham-controlled animal study. University medical center research laboratory. Adult male Sprague-Dawley rats. Rats were subjected to a 30% total body surface area, full skin thickness burn. Infection in rats was induced via intraperitoneal inoculation of E. coli, 10(9) colony forming units/kg, with or without a prior burn. Rat Peyer's patch and splenic T lymphocytes were isolated by using a nylon wool cell purification protocol. T-cell proliferation, interleukin-2 production, and Ca(2+) signaling responses were measured after stimulation of cells with the mitogen, concanavalin A. T-cell proliferation was determined by measuring incorporation of (3)H-thymidine into T-cell cultures. Interleukin-2 production by T-cell cultures was measured by using enzyme-linked immunosorbent assay. Intracellular T-cell Ca2(+ )concentration, [Ca(2+)](i), was measured by the use of Ca(2+)-specific fluorescent label, fura-2, and its fluorometric quantification. [Ca(2+)](i) was also evaluated by the use of digital video imaging of fura-2 loaded individual T cells. T-cell proliferation and interleukin-2 production were suppressed substantially in both Peyer's patch and splenic T cells 3 days after either the initial burn alone or burn followed by the E. coli inoculation at 24 hrs after the initial burn. There seemed to be no demonstrable additive effects of E. coli infection on the effects produced by burn injury alone. The T-cell proliferation and interleukin-2 production suppressions with burn or burn-plus-infection insults were correlated with attenuated Ca(2+) signaling. E. coli infection alone suppressed T-cell proliferation in Peyer's patch but not in splenic T cells at 2 days postbacterial inoculation; E. coli infection had no effect on

  11. Alterations induced in Escherichia Coli cells by gamma radiation

    International Nuclear Information System (INIS)

    Kappke, J.; Schelin, H.R.; Paschuk, S.A.; Denyak, V.; Silva, E.R. da; Jesus, E.F.O. de; Lopes, R.T.; Carlin, N.; Toledo, E.S.

    2007-01-01

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

  12. [A family history of renal lithiasis in children diagnosed of urinary tract infection by Escherichia coli].

    Science.gov (United States)

    García Nieto, Víctor; Sotoca Fernández, Jorge; O'Hagan, Monica; Arango Sancho, Pedro; Luis Yanes, Maria Isabel

    2018-04-01

    Urinary tract infections (UTI) caused by Escherichia coli (E. coli) are common in patients with idiopathic hypercalciuria. As both UTI and hypercalciuria (prelithiasis) have a genetic basis, we wanted to know whether the family history of urolithiasis is more common in children with UTIs caused by E. coli. Secondarily, we wondered if the renal scars are more common in children with prelithiasis. Ambispective study with collected data from 104 patients (40 male, 64 female) followed after having been diagnosed of UTI by E. coli at least once. These patients were asked about the existence of urolithiasis in relatives. The calcium and citrate urinary elimination was qunatified in 80 children. In the total sample, family history was positive for urolithiasis in a significantly higher frequency in those children (n=71; 68.3%) than in the control population in our area (29.7%; previously published data). Prelithiasis frequency in children with UTI was 47.5% (38/80). An association was observed between the diagnosis of prelithiasis both with family history of urolithiasis (P=.030) and the diagnosis of vesicoureteral reflux (P=.034). Children who developed renal scarring had an increased risk of prelithiasis (OR 5.3; P=.033). The frequency of family history of urolithiasis in children with UTI caused by E. coli is very high. Based on our results we hypothesize that the predisposition to lithiasis can involve a constitutively altered defense to E. coli and, therefore, a greater possibility for renal scars. Copyright © 2017 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. Molecular analysis of formaldehyde-induced mutations in human lymphoblasts and E. coli

    International Nuclear Information System (INIS)

    Crosby, R.M.; Richardson, K.K.; Craft, T.R.; Benforado, K.B.; Liber, H.L.; Skopek, T.R.

    1988-01-01

    The molecular nature of formaldehyde (HCHO)-induced mutations was studied in both human lymphoblasts and E. coli. Thirty HPRT - human lymphoblast colonies induced by eight repetitive 150 μM HCHO treatments were characterized by Southern blot analysis. Fourteen of these mutants (47%) had visible deletions of some or all of the X-linked HPRT bands, indicating that HCHO can induce large losses of DNA in human lymphoblasts. In E. coli., DNA alterations induced by HCHO were characterized with use of the xanthine guanine phosphoribosyl transferase (gpt) gene as the genetic target. Exposure of E. coli to 4 mM HCHO for 1 hr induced large insertions (41%), large deletions (18%), and point mutations (41%). Dideoxy DNA sequencing revealed that most of the point mutations were transversions at GC base pairs. In contrast, exposure of E. coli to 40 mM HCHO for 1 hr produced 92% point mutations, 62% of which were transitions at a single AT base pair in the gene. Therefore, HCHO is capable of producing different genetic alterations in E. coli at different concentrations, suggesting fundamental differences in the mutagenic mechanisms operating at the two concentrations used. Naked pSV2gpt plasmid DNA was exposed to 3.3 or 10 mM HCHO and transformed into E. coli. Most of the resulting mutations were frameshifts, again suggesting a different mutagenic mechanism

  14. Treatment with high-dose antidepressants severely exacerbates the pathological outcome of experimental Escherichia coli infections in poultry

    DEFF Research Database (Denmark)

    Kromann, Sofie; Kudirkiene, Egle; Li, Lili

    2017-01-01

    infection in poultry. A total of 40 chickens were divided in four groups of 10 chickens each. All chickens were challenged with 4x103 colony forming units (CFU) of a tetracycline resistant E. coli strain using a surgical infection model, and subsequently treated with either high-dose sertraline...... combined with tetracycline. In conclusion high-dose treatments (four times the maximum therapeutic dose for treating human depression) with sertraline as an adjuvant for treatment of antibiotic resistant E. coli infections exacerbate the pathological outcome of infection in chickens....

  15. Rapid Growth of Uropathogenic Escherichia coli during Human Urinary Tract Infection

    Directory of Open Access Journals (Sweden)

    Valerie S. Forsyth

    2018-03-01

    Full Text Available Uropathogenic Escherichia coli (UPEC strains cause most uncomplicated urinary tract infections (UTIs. These strains are a subgroup of extraintestinal pathogenic E. coli (ExPEC strains that infect extraintestinal sites, including urinary tract, meninges, bloodstream, lungs, and surgical sites. Here, we hypothesize that UPEC isolates adapt to and grow more rapidly within the urinary tract than other E. coli isolates and survive in that niche. To date, there has not been a reliable method available to measure their growth rate in vivo. Here we used two methods: segregation of nonreplicating plasmid pGTR902, and peak-to-trough ratio (PTR, a sequencing-based method that enumerates bacterial chromosomal replication forks present during cell division. In the murine model of UTI, UPEC strain growth was robust in vivo, matching or exceeding in vitro growth rates and only slowing after reaching high CFU counts at 24 and 30 h postinoculation (hpi. In contrast, asymptomatic bacteriuria (ABU strains tended to maintain high growth rates in vivo at 6, 24, and 30 hpi, and population densities did not increase, suggesting that host responses or elimination limited population growth. Fecal strains displayed moderate growth rates at 6 hpi but did not survive to later times. By PTR, E. coli in urine of human patients with UTIs displayed extraordinarily rapid growth during active infection, with a mean doubling time of 22.4 min. Thus, in addition to traditional virulence determinants, including adhesins, toxins, iron acquisition, and motility, very high growth rates in vivo and resistance to the innate immune response appear to be critical phenotypes of UPEC strains.

  16. E. coli infection modulates the pharmacokinetics of oral enrofloxacin by targeting P-glycoprotein in small intestine and CYP450 3A in liver and kidney of broilers.

    Science.gov (United States)

    Guo, Mengjie; Sun, Yong; Zhang, Yu; Bughio, Shamsuddin; Dai, Xiaohua; Ren, Weilong; Wang, Liping

    2014-01-01

    P-glycoprotein (P-gp) expression determines the absorption, distribution, metabolism and excretion of many drugs in the body. Also, up-regulation of P-gp acts as a defense mechanism against acute inflammation. This study examined expression levels of abcb1 mRNA and localization of P-gp protein in the liver, kidney, duodenum, jejunum and ileum in healthy and E. coli infected broilers by real time RT-PCR and immunohistochemistry. Meanwhile, pharmacokinetics of orally administered enrofloxacin was also investigated in healthy and infected broilers by HPLC. The results indicated that E. coli infection up-regulated expression of abcb1 mRNA levels significantly in the kidney, jejunum and ileum (P0.05). However, the expression level of CYP 3A37 mRNA were observed significantly decreased only in liver and kidney of E. coli infected broilers (Penrofloxacin, significantly decreased Cmax (0.34 vs 0.98 µg mL(-1), P = 0.000) and AUC0-12h (4.37 vs 8.88 µg mL(-1) h, P = 0.042) of enrofloxacin, but increased Tmax (8.32 vs 3.28 h, P = 0.040), T1/2a(2.66 vs 1.64 h(-1), P = 0.050) and V/F (26.7 vs 5.2 L, P = 0.040). Treatment with verapamil, an inhibitor of P-gp, significantly improved the absorption of enrofloxacin in both healthy and infected broilers. The results suggest that the E. coli infection induces intestine P-gp expression, altering the absorption of orally administered enrofloxacin in broilers.

  17. "Population structure of drug-susceptible, -resistant and ESBL-producing Escherichia coli from community-acquired urinary tract infections"

    DEFF Research Database (Denmark)

    Hertz, Frederik Boetius; Nielsen, Jesper Boye; Schønning, Kristian

    2016-01-01

    BACKGROUND: Escherichia coli is the most common cause of urinary tract infection (UTI). The pathogenic isolates are becoming increasingly resistant to antibiotics; with a worldwide dissemination of resistant sequence types (ST). We characterized three different uropathogenic E. coli populations...

  18. The prevalence of virulence genes of E. coli strains isolated from children with urinary tract infection

    Directory of Open Access Journals (Sweden)

    Farshad Shohreh

    2009-01-01

    Full Text Available To evaluate the prevalence of virulence genes in E. coli strains isolated from urine samples of children with urinary tract infection(UTI and their correlation with clinical data, we iso-lated E. coli strains from urine samples of children with UTI during the period of August 2005 - August 2006 and studied them for the presence of the virulence genes by PCR. A total of 96 E. coli strains were isolated. The prevalence of genes, pyelonephritis associated pili (pap genes, S-family adhesions (sfa gene, hemolysin (hly gene, and cytotoxic nercotizing factor type 1 (cnf-1-1 gene among the isolated strains was 27.1%, 14.6%, 13.5% and 22.9 %, respectively. Pyelonephritis was more prevalent in the cases with positive virulence genes. The results showed significant correlation bet-ween age of the patient and the presence of the genes (P< 0.05. Cnf-1 gene was significantly more common in samples of patients with abnormal finding on the ultrasound of kidneys (P= 0.049. Our study demonstrated higher prevalence of pyelonephritis in the presence of E. coli virulence genes. Detection of the genes in urine samples may help in the management of UTI.

  19. Effect of a lytic bacteriophage on rabbits experimentally infected with pathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    J. Zhao

    2017-09-01

    Full Text Available Pathogenic Escherichia coli (E. coli is severely threatening the rabbit industry in China, and the concern over antibiotic-resistant bacteria has given rise to an urgent need for antibiotic alternatives. In this study, a member (ZRP1 of the Myoviridae family was isolated from rabbit faeces using a strain of rabbit atypical enteropathogenic E. coli (ZR1 as host. The one-step growth curve indicated that the latent period was around 25 to 30 min and the burst size was 144±31 plaque-forming unit/cell. The rate of phage-resistant mutation was 7×10–5±4×10–5. When the bacteriophage input at the multiplicity of infection (MOI was 0.1, 1 or 10, the growth of host E. coli in broth was inhibited for 5 h. A single intravenous injection of ZRP1 at MOI 0.1, 1 or 10 significantly prolonged the survival time of rabbits which simultaneously received a lethal dose of ZR1.

  20. The prevalence of virulence genes of E. coli strains isolated from children with urinary tract infection

    International Nuclear Information System (INIS)

    Farshad, Shohreh; Emamghorashi, Fatemeh

    2009-01-01

    To evaluate the prevalence of virulence genes in E. coli strains isolated from urine samples of children with urinary tract infection(UTI) and their correlation with clinical data, we isolated E. coli strains from urine samples of children with UTI during the period of August 2005 - August 2006 and studied them for the presence of the virulence genes by PCR. A total of 96 E. coli strains were isolated. The prevalence of genes, pyelonephritis associated pili (pap genes), S-family adhesions (sfa gene), hemolysin (hly gene), and cytotoxic nercotizing factor type 1 (cnf-1-1 gene) among the isolated strains was 27.1%, 14.6%, 13.5% and 22.9 %, respectively. Pyelonephritis was more prevalent in the cases with positive virulence genes. The results showed significant correlation between age of the patient and the presence of the genes (P< 0.05). Cnf-1 gene was significantly more common in samples of patients with abnormal finding on the ultrasound of kidneys (P0.049). Our study demonstrated higher prevalence of pyelonephritis in the presence of E. coli virulence genes. Detection of the genes in urine samples may help in the management of UTI. (author)

  1. Emergence of Escherichia coli encoding Shiga toxin 2f in human Shiga toxin-producing E-coli (STEC) infections in the Netherlands, January 2008 to December 2011

    NARCIS (Netherlands)

    Friesema, I.; van der Zwaluw, K.; Schuurman, T.; Kooistra-Smid, M.; Franz, E.; van Duynhoven, Y.; van Pelt, W.

    2014-01-01

    The Shiga toxins of Shiga toxin-producing Escherichia coli (STEC) can be divided into Shiga toxin 1 (Stx1) and Shiga toxin 2 (Stx2) with several sub-variants. Variant Stx(2f) is one of the latest described, but has been rarely associated with symptomatic human infections. In the enhanced STEC

  2. The innate immune response to lower respiratory tract E. Coli infection and the role of the CCL2-CCR2 axis in neonatal mice.

    Science.gov (United States)

    McGrath-Morrow, Sharon A; Ndeh, Roland; Collaco, Joseph M; Poupore, Amy K; Dikeman, Dustin; Zhong, Qiong; Singer, Benjamin D; D'Alessio, Franco; Scott, Alan

    2017-09-01

    Neonates have greater morbidity/mortality from lower respiratory tract infections (LRTI) compared to older children. Lack of conditioning of the pulmonary immune system due to limited environmental exposures and/or infectious challenges likely contributes to the increase susceptibility in the neonate. In this study, we sought to gain insights into the nature and dynamics of the neonatal pulmonary immune response to LRTI using a murine model. Wildtype (WT) and Ccr2 -/- C57BL/6 neonatal and juvenile mice received E. coli or PBS by direct pharyngeal aspiration. Flow cytometry was used to measure immune cell dynamics and identify cytokine-producing cells. Real-time PCR and ELISA were used to measure cytokine/chemokine expression. Innate immune cell recruitment in response to E. coli-induced LRTI was delayed in the neonatal lung compared to juvenile lung. Lung clearance of bacteria was also significantly delayed in the neonate. Ccr2 -/- neonates, which lack an intact CCL2-CCR2 axis, had higher mortality after E. coli challenged than Ccr2 +/+ neonates. A greater percentage of CD8 + T cells and monocytes from WT neonates challenged with E. coli produced TNF compared to controls. The pulmonary immune response to E. coli-induced LRTI differed significantly between neonatal and juvenile mice. Neonates were more susceptible to increasing doses of E. coli and exhibited greater mortality than juveniles. In the absence of an intact CCL2-CCR2 axis, susceptibility to LRTI-induced mortality was further increased in neonatal mice. Taken together these findings underscore the importance of age-related differences in the innate immune response to LRTI during early stages of postnatal life. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Role of Uropathogenic Escherichia coli Virulence Factors in Development of Urinary Tract Infection and Kidney Damage

    Science.gov (United States)

    Bien, Justyna; Sokolova, Olga; Bozko, Przemyslaw

    2012-01-01

    Uropathogenic Escherichia coli (UPEC) is a causative agent in the vast majority of urinary tract infections (UTIs), including cystitis and pyelonephritis, and infectious complications, which may result in acute renal failure in healthy individuals as well as in renal transplant patients. UPEC expresses a multitude of virulence factors to break the inertia of the mucosal barrier. In response to the breach by UPEC into the normally sterile urinary tract, host inflammatory responses are triggered leading to cytokine production, neutrophil influx, and the exfoliation of infected bladder epithelial cells. Several signaling pathways activated during UPEC infection, including the pathways known to activate the innate immune response, interact with calcium-dependent signaling pathways. Some UPEC isolates, however, might possess strategies to delay or suppress the activation of components of the innate host response in the urinary tract. Studies published in the recent past provide new information regarding how virulence factors of uropathogenic E. coli are involved in activation of the innate host response. Despite numerous host defense mechanisms, UPEC can persist within the urinary tract and may serve as a reservoir for recurrent infections and serious complications. Presentation of the molecular details of these events is essential for development of successful strategies for prevention of human UTIs and urological complications associated with UTIs. PMID:22506110

  4. Thymus transcriptome reveals novel pathways in response to avian pathogenic Escherichia coli infection.

    Science.gov (United States)

    Sun, H; Liu, P; Nolan, L K; Lamont, S J

    2016-12-01

    Avian pathogenic Escherichia coli (APEC) can cause significant morbidity in chickens. The thymus provides the essential environment for T cell development; however, the thymus transcriptome has not been examined for gene expression in response to APEC infection. An improved understanding of the host genomic response to APEC infection could inform future breeding programs for disease resistance and APEC control. We therefore analyzed the transcriptome of the thymus of birds challenged with APEC, contrasting susceptible and resistant phenotypes. Thousands of genes were differentially expressed in birds of the 5-day post infection (dpi) challenged-susceptible group vs. 5 dpi non-challenged, in 5 dpi challenged-susceptible vs. 5 dpi challenged-resistant birds, as well as in 5 dpi vs. one dpi challenged-susceptible birds. The Toll-like receptor signaling pathway was the major innate immune response for birds to respond to APEC infection. Moreover, lysosome and cell adhesion molecules pathways were common mechanisms for chicken response to APEC infection. The T-cell receptor signaling pathway, cell cycle, and p53 signaling pathways were significantly activated in resistant birds to resist APEC infection. These results provide a comprehensive assessment of global gene networks and biological functionalities of differentially expressed genes in the thymus under APEC infection. These findings provide novel insights into key molecular genetic mechanisms that differentiate host resistance from susceptibility in this primary lymphoid tissue, the thymus. © The Author 2016. Published by Oxford University Press on behalf of Poultry Science Association.

  5. Fluoroquinolone-Resistant Escherichia coli Infections after Transrectal Biopsy of the Prostate in the Veterans Affairs Healthcare System

    Directory of Open Access Journals (Sweden)

    Elie Antoun Saade

    2016-09-01

    Full Text Available Background: Recent reports suggest that infections due to fluoroquinolone-resistant Escherichia coli (E. coli are an increasingly common complication of transrectal biopsy of the prostate (TBP in the United States. A better understanding of the magnitude and scope of these infections is needed to guide prevention efforts. Our objective is to determine whether the incidence of infections due to fluoroquinolone-resistant E. coli after TBP has increased nationwide in the Veterans Affairs Health Care System and to identify risk factors for infection. Methods: We performed a retrospective, observational cohort study and a nested case-control study within the US Deparment of Veterans Affairs Healthcare System. The primary outcomes were the incidence of urinary tract infection (UTI and bacteremia with E. coli and with fluoroquinolone-resistant E. coli strains within 30 days after TBP. Secondary endpoints focused on the correlation between fluoroquinolone-resistance in all urinary E. coli isolates and post-TBP infection and risk factors for infection due to fluoroquinolone-resistant E. coli infection. Results: 245 618 patients undergoing 302 168 TBP procedures from 2000 through 2013 were included in the cohort study, and 59 469 patients undergoing TBP from 2011 through 2013 were included in the nested case-control study. Between 2000 and 2013, there was a 5-fold increase in the incidence of E. coli UTI (0.18%–0.93% and a 4-fold increase in the incidence of E. coli bacteremia (0.04%–0.18% after TBP that was attributable to an increase in the incidence of fluoroquinolone-resistant E. coli UTI (0.03%–0.75% and bacteremia (0.01%–0.14%. The increasing incidence of fluoroquinolone-resistant E. coli infections after TBP occurred in parallel with increasing rates of fluoroquinolone-resistance in all urinary E. coli isolates. By multivariable logistic regression analysis, independent risk factors for fluoroquinolone

  6. Taurine modulates neutrophil function but potentiates uropathogenic E. coli infection in the murine bladder.

    LENUS (Irish Health Repository)

    Condron, Claire

    2010-08-01

    Eradication of a urinary tract infection (UTI) appears to be related to a number of innate host defence mechanisms and their interactions with invading bacteria. Recurrent UTIs (rUTIs) pose a difficult problem in that these bacteria use both host and bacterial factors to evade elimination. Neutrophil bactericidal function is depressed, both systemically and in urine, in patients with a history of recurrent UTI. Taurine is a semi-essential amino acid and is successful in preserving neutrophil bactericidal function in urine. Taurine may preserve neutrophil function at the urothelium and thus aid UTI resolution. Adult female (6 weeks old) C57Bl\\/6 mice were randomised into three groups: a saline gavage only control group, a saline gavage + E. coli group, and a taurine gavage + E. coli group [21 g\\/70 kg taurine in 0.9% normal saline (N\\/S) for 5 days]. Whilst taurine gavage pre-treatment resulted in increased serum neutrophils respiratory burst activity, at the urothelial-endothelial interface it caused higher colony forming units in the urine and a higher incidence of E. coli invasion in the bladder wall with no evidence of increased bladder wall neutrophils infiltration on MPO assay of histological assessment. Histologically there was also evidence of reduced bladder inflammation and urothelial cell apoptosis. In conclusion, taurine effectively increases neutrophils activity but given its anti-inflammatory properties, at the expense of decreased urothelial-endothelial activation thus preventing clearance of active E. coli infection in the bladder. Despite the negative results, this study demonstrates the importance of modulating interactions at the urothelial interface.

  7. Pharmacokinetics of amoxicillin after oral administration in recently weaned piglets with experimentally induced Escherichia coli subtype O149 : F4 diarrhea

    DEFF Research Database (Denmark)

    Jensen, G.M.; Lykkesfeldt, J.; Frydendahl, K.

    2004-01-01

    Objective-To measure the effect of Escherichia coli subtype 0149:F4-induced diarrhea on the pharmacokinetics of orally administered amoxicillin in affected piglets relative to that of uninfected piglets. Animals-22 healthy 4-week-old recently weaned Danish crossbred piglets. Procedure-12 piglets...... were orally inoculated through gastric intubation with 10(9) CFUs of an E coli 0149:F4 strain and responded by developing diarrhea 12 to 16 hours later. Piglets were dosed with amoxicillin trihydrate solution (20 mg/kg) by gastric intubation. A control group of 10 age-matched piglets without signs...... that the concentration of the antimicrobial at the site of infection reflects the systemic concentration, higher doses of amoxicillin in the treatment of piglets with E coli 0149:F4-induced diarrhea may be appropriate....

  8. Green tea as an effective antimicrobial for urinary tract infections caused by Escherichia coli

    Directory of Open Access Journals (Sweden)

    Wanda eReygaert

    2013-06-01

    Full Text Available Background: Urinary tract infections (UTIs are a very most common type of infection worldwide, and result in billions of dollars in medical care costs. Escherichia coli is the infective agent for 80%-90% of all UTIs. Green tea, derived from leaves of the Camellia sinensis plant has been shown to have various potential health benefits (e.g. cardiovascular disease and cancer. The major beneficial components of green tea have been characterized, and are now known to be polyphenolic catechins. The main catechins in green tea are (--epicatechin-3-gallate (ECG, (--epigallocatechin (EGC, (--epicatechin (EC, and (--epigallocatechin-3-gallate (EGCG. EGCG and EGC have been shown to have antimicrobial effects, but only EGC has been shown to be excreted in urine. Isolates of E. coli from urinary tract infections collected between 2007-2008 were characterized for antimicrobial resistance to standard drugs. Then 80 of these isolates, representing a wide spectrum of antimicrobial susceptibility patterns, were selected for testing using an extract of green tea.Results: The concentrations of green tea extract tested were 0, 2.5, 3.0, 3.5, and 4.0 mg/ml. All of the strains tested, except one, had MICs of ≤4.0 mg/ml, with 40% of the isolates having an MIC of ≤2.5 mg/ml, 36% of the isolates having an MIC of ≤3.0 mg/ml, 18% of the isolates having an MIC of ≤3.5 mg/ml, and 5% of the isolates having an MIC of ≤4.0 mg/ml. Two control strains varied in susceptibility, one having an MIC of ≤2.5 mg/ml, another having an MIC of ≤3.5 mg/ml, and the third having an MIC of ≤4.0 mg/ml.Conclusion: Since EGC has been shown to have antimicrobial effects on E. coli, and EGC has been shown to be excreted in the urine in a high enough concentration to potentially be effective as an antimicrobial; these MIC results suggest that ingesting green tea could have potential antimicrobial effects on urinary tract infections caused by E. coli.

  9. Risk of Escherichia coli O157:H7 infection linked to the consumption of beef

    Directory of Open Access Journals (Sweden)

    Premarathne, J.M.K.J.K

    2017-05-01

    Full Text Available Escherichia coli O157:H7 is a major food-borne pathogen that has resulted in numerous outbreaks around the world. Widespread distribution of the organism in various ecological niches impedes the control measures. This study aimed to detect and quantify E. coli O157:H7 in beef sold in wet markets and hypermarkets in Malaysia and to determine the risk of E. coli O157:H7 infection linked to consumption of beef. The rfbO157 and flicH7 primers targeted on somatic antigen (O157 and flagellar antigen (H7 respectively of E. coli O157:H7 was used for the MPN-PCR method. A total of 99 beef samples were collected from local wet markets and hypermarkets. The highest E. coli O157:H7 contamination rate was observed in beef samples collected from wet markets (89.50%, whereas the contamination rate in hyper market A and B were compratively low (35.35 and 20% respectively. However, the microbial load was highest in the beef samples from hypermarket A (1100 MPN/g while E. coli O157:H7 bacterial load in beef samples from hypermarket B and wet market ranged from 3 to 93 MPN/g and 3 to 240 MPN/g, respectively. Using the Quantitative Microbial Risk Assessment (QMRA approach the risk was estimated incorporating the findings of the prevalence study and predictions based on home storage, cooking and consumption patterns. Three different exposure pathways were investigated to estimate the risk associated with contaminated beef and Monte Carlo simulation was used to determine the level of uncertainty. The developed model predicated that consumption of contaminated beef can be accountable for 1.83E+06 E. coli O157:H7 cases per year in Malaysia. The reliability of the model, data gaps and further research needs, is discussed. Through continuous improvement Quantitative Microbial Risk Assessment provides valuable insight into controlling and prevention strategies.

  10. Medical and economic impact of extraintestinal infections due to Escherichia coli: focus on an increasingly important endemic problem.

    Science.gov (United States)

    Russo, Thomas A; Johnson, James R

    2003-04-01

    Escherichia coli is probably the best-known bacterial species and one of the most frequently isolated organisms from clinical specimens. Despite this, underappreciation and misunderstandings exist among medical professionals and the lay public alike regarding E. coli as an extraintestinal pathogen. Underappreciated features include (i) the wide variety of extraintestinal infections E. coli can cause, (ii) the high incidence and associated morbidity, mortality, and costs of these diverse clinical syndromes, (iii) the pathogenic potential of different groups of E. coli strains for causing intestinal versus extraintestinal disease, and (iv) increasing antimicrobial resistance. In this era in which health news often sensationalizes uncommon infection syndromes or pathogens, the strains of E. coli that cause extraintestinal infection are an increasingly important endemic problem and underappreciated "killers". Billions of health care dollars, millions of work days, and hundreds of thousands of lives are lost each year to extraintestinal infections due to E. coli. New treatments and prevention measures will be needed for improved outcomes and a diminished disease burden.

  11. Outbreak of Non-O157 Shiga Toxin-Producing Escherichia coli Infection from Consumption of Beef Sausage

    DEFF Research Database (Denmark)

    Ethelberg, S.; Smith, B.; Torpdahl, M.

    2009-01-01

    We describe an outbreak of Shiga toxin-producing Escherichia coli O26: H11 infection in 20 patients (median age, 2 years). The source of the infection was an organic fermented beef sausage. The source was discovered by using credit card information to obtain and compare customer transaction records...

  12. Employing Escherichia coli-derived outer membrane vesicles as an antigen delivery platform elicits protective immunity against Acinetobacter baumannii infection

    Science.gov (United States)

    Huang, Weiwei; Wang, Shijie; Yao, Yufeng; Xia, Ye; Yang, Xu; Li, Kui; Sun, Pengyan; Liu, Cunbao; Sun, Wenjia; Bai, Hongmei; Chu, Xiaojie; Li, Yang; Ma, Yanbing

    2016-11-01

    Outer membrane vesicles (OMVs) have proven to be highly immunogenic and induced an immune response against bacterial infection in human clinics and animal models. We sought to investigate whether engineered OMVs can be a feasible antigen-delivery platform for efficiently inducing specific antibody responses. In this study, Omp22 (an outer membrane protein of A. baumannii) was displayed on E. coli DH5α-derived OMVs (Omp22-OMVs) using recombinant gene technology. The morphological features of Omp22-OMVs were similar to those of wild-type OMVs (wtOMVs). Immunization with Omp22-OMVs induced high titers of Omp22-specific antibodies. In a murine sepsis model, Omp22-OMV immunization significantly protected mice from lethal challenge with a clinically isolated A. baumannii strain, which was evidenced by the increased survival rate of the mice, the reduced bacterial burdens in the lung, spleen, liver, kidney, and blood, and the suppressed serum levels of inflammatory cytokines. In vitro opsonophagocytosis assays showed that antiserum collected from Omp22-OMV-immunized mice had bactericidal activity against clinical isolates, which was partly specific antibody-dependent. These results strongly indicated that engineered OMVs could display a whole heterologous protein (~22 kDa) on the surface and effectively induce specific antibody responses, and thus OMVs have the potential to be a feasible vaccine platform.

  13. [Resistence of Escherichia coli, the most frequent cause of urinary tract infection in children, to antibiotics].

    Science.gov (United States)

    Stojanović, Vesna; Milosević, Biljana

    2010-01-01

    Urinary tract infections (UTI) take the second place in the incidence of bacterial infection in children. Escherichia coli is a cause of infection in 85-90%. A periodic evaluation of the resistance to antimicrobial drugs has to be performed in each geographic region, since investigations confirmed that the resistance of bacteria causing UTI has been in progress. A retrospective investigation has been performed, comprising the two time periods in the range of 10 years in order to identify the prevalence and resistance of the bacteria causing UTI in the patients treated at the Department of Nephrology of Institute for Child and Youth Health Care of Vojvodina. During the first investigated period from January 1996 up to December 1997, there were 163 urin analyses performed vs 134 urine analyses in the second period, starting from January 2006 to December 2007. In both periods, Escherichia coli, was the most frequent cause of UTI (82.1% in 1996/97 vs 86.50% in 2006/07). During this ten-year period, the resistance of Escherichia coli increased both to ampicillin (from 53% to 69% (p > 0.05) and to trimethoprim/sulfamethoxazole (34% vs 55%; p resistance to ceftazidim, gentamycin and nalidixic acid, but significant increase to ampicillin, trimethoprim/sulfamethoxazole and cephalexin. For the initial therapy of UTI in the Province of Vojvodina we recommend: perorally--ephalosporins I, II and III generation, and in case when the child is not capable to get therapy perorally, or in the case of highly febrile infant--ephalosporins III generation parenterally.

  14. Temporal Regulation of fim Genes in Uropathogenic Escherichia coli during Infection of the Murine Urinary Tract

    Directory of Open Access Journals (Sweden)

    William R. Schwan

    2017-01-01

    Full Text Available Uropathogenic Escherichia coli (UPEC adhere to cells in the human urinary tract via type 1 pili that undergo phase variation where a 314-bp fimS DNA element flips between Phase-ON and Phase-OFF orientations through two site-specific recombinases, FimB and FimE. Three fim-lux operon transcriptional fusions were created and moved into the clinical UPEC isolate NU149 to determine their temporal regulation in UPEC growing in the urinary tract. Within murine urinary tracts, the UPEC strains demonstrated elevated transcription of fimA and fimB early in the infection, but lower transcription by the fifth day in murine kidneys. In contrast, fimE transcription was much lower than either fimA or fimB early, increased markedly at 24 h after inoculation, and then dropped five days after inoculation. Positioning of fimS was primarily in the Phase-ON position over the time span in UPEC infected bladders, whereas in UPEC infected murine kidneys the Phase-OFF orientation was favored by the fifth day after inoculation. Hemagglutination titers with guinea pig erythrocytes remained constant in UPEC growing in infected murine bladders but fell substantially in UPEC infected kidneys over time. Our results show temporal in vivo regulation of fim gene expression in different environmental niches when UPEC infects the murine urinary tract.

  15. Variations in virulence of avian pathogenic Escherichia coli demonstrated by the use of a new in vivo infection model

    DEFF Research Database (Denmark)

    Pors, Susanne Elisabeth; Olsen, Rikke Heidemann; Christensen, Jens Peter

    2014-01-01

    , E. coli was found in pure culture from one or more positions in the oviduct and the liver. Birds receiving sterile broth did not culture positive and demonstrated no gross lesions. Subsequently, 19 birds were inoculated with an isolate of E. coli ST95 and 20 birds with an isolate of E. coli ST141....... Major variation in virulence was observed between the two isolates used in relation to clinical signs, gross lesions and histopathology. In contrast to E. coli ST141, E. coli ST95 caused severe clinical signs, epithelial necrosis of the oviduct and purulent salpingitis. The results of the study show...... the potential of the model in studies of the pathogenesis of infections and virulence of bacteria of the oviduct....

  16. Spleen transcriptome response to infection with avian pathogenic Escherichia coli in broiler chickens.

    Science.gov (United States)

    Sandford, Erin E; Orr, Megan; Balfanz, Emma; Bowerman, Nate; Li, Xianyao; Zhou, Huaijun; Johnson, Timothy J; Kariyawasam, Subhashinie; Liu, Peng; Nolan, Lisa K; Lamont, Susan J

    2011-09-27

    Avian pathogenic Escherichia coli (APEC) is detrimental to poultry health and its zoonotic potential is a food safety concern. Regulation of antimicrobials in food-production animals has put greater focus on enhancing host resistance to bacterial infections through genetics. To better define effective mechanism of host resistance, global gene expression in the spleen of chickens, harvested at two times post-infection (PI) with APEC, was measured using microarray technology, in a design that will enable investigation of effects of vaccination, challenge, and pathology level. There were 1,101 genes significantly differentially expressed between severely infected and non-infected groups on day 1 PI and 1,723 on day 5 PI. Very little difference was seen between mildly infected and non-infected groups on either time point. Between birds exhibiting mild and severe pathology, there were 2 significantly differentially expressed genes on day 1 PI and 799 on day 5 PI. Groups with greater pathology had more genes with increased expression than decreased expression levels. Several predominate immune pathways, Toll-like receptor, Jak-STAT, and cytokine signaling, were represented between challenged and non-challenged groups. Vaccination had, surprisingly, no detectible effect on gene expression, although it significantly protected the birds from observable gross lesions. Functional characterization of significantly expressed genes revealed unique gene ontology classifications during each time point, with many unique to a particular treatment or class contrast. More severe pathology caused by APEC infection was associated with a high level of gene expression differences and increase in gene expression levels. Many of the significantly differentially expressed genes were unique to a particular treatment, pathology level or time point. The present study not only investigates the transcriptomic regulations of APEC infection, but also the degree of pathology associated with that

  17. Spleen transcriptome response to infection with avian pathogenic Escherichia coli in broiler chickens

    Directory of Open Access Journals (Sweden)

    Kariyawasam Subhashinie

    2011-09-01

    Full Text Available Abstract Background Avian pathogenic Escherichia coli (APEC is detrimental to poultry health and its zoonotic potential is a food safety concern. Regulation of antimicrobials in food-production animals has put greater focus on enhancing host resistance to bacterial infections through genetics. To better define effective mechanism of host resistance, global gene expression in the spleen of chickens, harvested at two times post-infection (PI with APEC, was measured using microarray technology, in a design that will enable investigation of effects of vaccination, challenge, and pathology level. Results There were 1,101 genes significantly differentially expressed between severely infected and non-infected groups on day 1 PI and 1,723 on day 5 PI. Very little difference was seen between mildly infected and non-infected groups on either time point. Between birds exhibiting mild and severe pathology, there were 2 significantly differentially expressed genes on day 1 PI and 799 on day 5 PI. Groups with greater pathology had more genes with increased expression than decreased expression levels. Several predominate immune pathways, Toll-like receptor, Jak-STAT, and cytokine signaling, were represented between challenged and non-challenged groups. Vaccination had, surprisingly, no detectible effect on gene expression, although it significantly protected the birds from observable gross lesions. Functional characterization of significantly expressed genes revealed unique gene ontology classifications during each time point, with many unique to a particular treatment or class contrast. Conclusions More severe pathology caused by APEC infection was associated with a high level of gene expression differences and increase in gene expression levels. Many of the significantly differentially expressed genes were unique to a particular treatment, pathology level or time point. The present study not only investigates the transcriptomic regulations of APEC infection

  18. Porphyromonas endodontalis lipopolysaccharides induce RANKL by mouse osteoblast in a way different from that of Escherichia coli lipopolysaccharide.

    Science.gov (United States)

    Tang, Yin; Sun, Feifei; Li, Xiaoting; Zhou, Yuan; Yin, Shihai; Zhou, Xuedong

    2011-12-01

    Porphyromonas endodontalis lipopolysaccharide (LPS) has been shown to have a high positive rate in infected root canals and symptomatic apical periodontitis. It may play an integral role as a potent stimulator of inflammatory cytokines involved in apical lesions. The receptor activator of nuclear factor-κB ligand (RANKL) has been proven to be the key regulator of bone remodeling. This study investigated P. endodontalis LPS-induced RANKL production and LPS signaling in mouse osteoblasts. LPS-induced RANKL production in mouse osteoblast MC3T3-E1 cells was measured by Western blot and real-time polymerase chain reaction, and the Toll-like receptors (TLRs) were determined by the blocking test using anti-TLRs antibodies. In addition, specific inhibitors were used to analyze the intracellular signaling pathways. Escherichia coli LPS was used as the control. Both of the anti-TLR2 and anti-TLR4 antibodies significantly (P endodontalis LPS; only anti-TLR2 antibody had a significant (P endodontalis LPS-infected osteoblasts (P endodontalis LPS has the ability to promote the expression of RANKL in mouse osteoblasts, and this induction was mainly through the TLR2/4-JNK signaling pathway, a situation quite different from that of typical bacterial endotoxin (E. coli LPS). Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  19. Parvovirus infection-induced DNA damage response

    Science.gov (United States)

    Luo, Yong; Qiu, Jianming

    2014-01-01

    Parvoviruses are a group of small DNA viruses with ssDNA genomes flanked by two inverted terminal structures. Due to a limited genetic resource they require host cellular factors and sometimes a helper virus for efficient viral replication. Recent studies have shown that parvoviruses interact with the DNA damage machinery, which has a significant impact on the life cycle of the virus as well as the fate of infected cells. In addition, due to special DNA structures of the viral genomes, parvoviruses are useful tools for the study of the molecular mechanisms underlying viral infection-induced DNA damage response (DDR). This review aims to summarize recent advances in parvovirus-induced DDR, with a focus on the diverse DDR pathways triggered by different parvoviruses and the consequences of DDR on the viral life cycle as well as the fate of infected cells. PMID:25429305

  20. Wave-induced mass transport affects daily Escherichia coli fluctuations in nearshore water

    Science.gov (United States)

    Ge, Zhongfu; Whitman, Richard L.; Nevers, Meredith B.; Phanikumar, Mantha S.

    2012-01-01

    Characterization of diel variability of fecal indicator bacteria concentration in nearshore waters is of particular importance for development of water sampling standards and protection of public health. Significant nighttime increase in Escherichia coli (E. coli) concentration in beach water, previously observed at marine sites, has also been identified in summer 2000 from fixed locations in waist- and knee-deep waters at Chicago 63rd Street Beach, an embayed, tideless, freshwater beach with low currents at night (approximately 0.015 m s–1). A theoretical model using wave-induced mass transport velocity for advection was developed to assess the contribution of surface waves to the observed nighttime E. coli replenishment in the nearshore water. Using average wave conditions for the summer season of year 2000, the model predicted an amount of E. coli transported from water of intermediate depth, where sediment resuspension occurred intermittently, that would be sufficient to have elevated E. coli concentration in the surf and swash zones as observed. The nighttime replenishment of E. coli in the surf and swash zones revealed here is an important phase in the cycle of diel variations of E. coli concentration in nearshore water. According to previous findings in Ge et al. (Environ. Sci. Technol. 2010, 44, 6731–6737), enhanced current circulation in the embayment during the day tends to displace and deposit material offshore, which partially sets up the system by the early evening for a new period of nighttime onshore movement. This wave-induced mass transport effect, although facilitating a significant base supply of material shoreward, can be perturbed or significantly influenced by high currents (orders of magnitude larger than a typical wave-induced mass transport velocity), current-induced turbulence, and tidal forcing.

  1. Detection of Enterohemorrhagic Escherichia coli Related Genes in E. coli Strains Belonging to B2 Phylogroup Isolated from Urinary Tract Infections in Combination with Antimicrobial Resistance Phenotypes

    Directory of Open Access Journals (Sweden)

    Hamid Staji

    2017-07-01

    Full Text Available Background:  This study was conducted to detect the prevalence of EHEC virulence genes and antimicrobial resistance profile of Escherichia coli strains belonging to B2 phylogroup implicated in Urinary tract infections in Semnan, Iran.Methods:   From 240 urine samples 160 E. coli strains were isolated, biochemically. Then, E. coli isolates were examined by Multiplex-PCR for phylogenetic typing and detection of virulence genes (hly, stx1, stx2, eae associated with Enterohemorrhagic E. coli. Finally, Antimicrobial resistance of E. coli isolates were characterized using Disk Diffusion method.  Results:  From 160 E. coli isolates, 75 strains (47% were assigned to B2 phylogenetic group and prevalence of virulence genes were as follow: hly (21.3%, stx1 (16%, stx2 (10.6% and eae (6.7%, subsequently.  Phenotypic antimicrobial resistance of B2 isolates showed that all isolates were sensitive to Meropenem and Furazolidone and then highest frequency of resistance was observed to Streptomycin, Oxytetracycline, Neomycin, Nalidixic acid and Ampicillin (98.7% to 49.3%. Also low resistance prevalence was observed in case of Ceftizoxime, Lincospectin, Imipenem, Chloramphenicol and flurefenicole (16% to 1.3%.Conclusion:   The data suggest a high prevalence of antibiotic resistance in UPEC strains belonging to B2 phylogroup even for the antimicrobials using in pet and farm animals and their potential to cause EHEC specific clinical symptoms which may represent a serious health risk since these strains can be transmitted to GI tract and act as a reservoir for other uropathogenic E. coli and commensal strains.

  2. Specific binding of lactoferrin to Escherichia coli isolated from human intestinal infections

    International Nuclear Information System (INIS)

    Naidu, S.S.; Erdei, J.; Forsgren, A.; Naidu, A.S.; Czirok, E.; Gado, I.; Kalfas, S.; Thoren, A.

    1991-01-01

    The degrees of human lactoferrin (HLf) and bovine lactoferrin (BLf) binding in 169 Escherichia coli strains isolated from human intestinal infections, and in an additional 68 strains isolated from healthy individuals, were examined in a 125 I-labelled protein binding assay. The binding was expressed as a percentage calculated from the total labelled ligand added to bacteria. The HLf and BLf binding to E. coli was in the range 3.7 to 73.4% and 4.8 to 61.6%, respectively. Enterotoxigenic strains demonstrated a significantly higher HLf binding (median = 19%) than enteropathogenic, enteroinvasive, enterohaemorrhagic strains or normal intestinal E. coli isolates (medians 6 to 9). Enteropathogenic strains belonging to serotypes O44 and O127 demonstrated significantly higher HLf binding compared to O26, O55, O111, O119 and O126. No significant differences in the degree of HLf or BLf binding were found between aerobactin-producing and non-producing strains. The interaction was further characterized in a high Lf-binging EPEC strain, E34663 (serotype O127). The binding was stable in the pH range 4.0 to 7.5, did not dissociate in the presence of 2M NaCl or 2M urea, and reached saturation within two h. Unlabelled HLf and BLf displaced the 125 I-HLf binding to E34663 in a dose-dependent manner. Apo- and iron-saturated forms of Lf demonstrated similar binding to E34663. Among various unlabelled subephithelial matrix proteins and carbohydrates tested (in 10 4 -fold excess) only fibronectin and fibrinogen caused a moderate inhibition of 125 I-HLf binding. According to Scatchard plot analysis, 5,400 HLf-binding sites/cell, with an affinity constant (K a ) of 1.4 x 10 -7 M, were estimated in strain E34663. These data establish the presence of a specific Lf-binding mechanism in E. coli. (au)

  3. Comparison of extended-spectrum-β-lactamase (ESBL) carrying Escherichia coli from sewage sludge and human urinary tract infection

    International Nuclear Information System (INIS)

    Zarfel, G.; Galler, H.; Feierl, G.; Haas, D.; Kittinger, C.; Leitner, E.; Grisold, A.J.; Mascher, F.; Posch, J.; Pertschy, B.; Marth, E.; Reinthaler, F.F.

    2013-01-01

    For many years, extended-spectrum-beta-lactamase (ESBL) producing bacteria were a problem mainly located in medical facilities. Within the last decade however, ESBL-producing bacteria have started spreading into the community and the environment. In this study, ESBL-producing Escherichia coli from sewage sludge were collected, analysed and compared to ESBL-E. coli from human urinary tract infections (UTIs). The dominant ESBL-gene-family in both sample groups was bla CTX-M , which is the most prevalent ESBL-gene-family in human infection. Still, the distribution of ESBL genes and the frequency of additional antibiotic resistances differed in the two sample sets. Nevertheless, phenotyping did not divide isolates of the two sources into separate groups, suggesting similar strains in both sample sets. We speculate that an exchange is taking place between the ESBL E. coli populations in infected humans and sewage sludge, most likely by the entry of ESBL E. coli from UTIs into the sewage system. - Highlights: ► ESBL E. coli strains from sewage sludge harbour the same dominant ESBL enzymes as human isolates. ► High resistance rates for important antibiotics can be found in isolated ESBL strains. ► High phenotypic diversity of ESBL E. coli isolates from sewage sludge and from human sources. - The distribution of ESBL resistance genes in isolates from patients and environmental samples.

  4. Role of climate in the spread of shiga toxin-producing Escherichia coli infection among children

    Science.gov (United States)

    Acquaotta, Fiorella; Ardissino, Gianluigi; Fratianni, Simona; Perrone, Michela

    2017-09-01

    Haemolytic-uraemic syndrome (HUS) is a rare disease mainly affecting children that develops as a complication of shiga toxin-producing Escherichia coli (STEC) infection. It is characterised by acute kidney injury, platelet consumption and mechanical destruction of red blood cells (haemolysis). In order to test the working hypothesis that the spread of the infection is influenced by specific climatic conditions, we analysed all of the identified cases of infection occurring between June 2010 and December 2013 in four provinces of Lombardy, Italy (Milano, Monza Brianza, Varese and Brescia), in which a STEC surveillance system has been developed as part of a preventive programme. In the selected provinces, we recorded in few days a great number of cases and clusters which are unrelated for spatially distant or for the disease are caused by different STEC serotypes. In order to investigate a common factor that favoured the onset of infection, we have analysed in detail the weather conditions of the areas. The daily series of temperature, rain and relative humidity were studied to show the common climate peculiarities whilst the correlation coefficient and the principal component analysis (PCA) were used to point out the meteorological variable, maximum temperature, as the principal climate element in the onset of the infection. The use of distributed lag non-linear models (DLNM) and the climate indices characterising heat waves (HWs) has allowed to identify the weather conditions associated with STEC infection. The study highlighted a close temporal correlation between STEC infection in children and the number, duration and frequency of heat waves. In particular, if the maximum temperature is greater than 90th percentile, days classified as very hot, for 3 or more consecutive days, the risk of infection is increasing.

  5. Escherichia coli surface display of single-chain antibody VRC01 against HIV-1 infection

    International Nuclear Information System (INIS)

    Wang, Lin-Xu; Mellon, Michael; Bowder, Dane; Quinn, Meghan; Shea, Danielle; Wood, Charles; Xiang, Shi-Hua

    2015-01-01

    Human immunodeficiency virus type 1 (HIV-1) transmission and infection occur mainly via the mucosal surfaces. The commensal bacteria residing in these surfaces can potentially be employed as a vehicle for delivering inhibitors to prevent HIV-1 infection. In this study, we have employed a bacteria-based strategy to display a broadly neutralizing antibody VRC01, which could potentially be used to prevent HIV-1 infection. The VRC01 antibody mimics CD4-binding to gp120 and has broadly neutralization activities against HIV-1. We have designed a construct that can express the fusion peptide of the scFv-VRC01 antibody together with the autotransporter β-barrel domain of IgAP gene from Neisseria gonorrhoeae, which enabled surface display of the antibody molecule. Our results indicate that the scFv-VRC01 antibody molecule was displayed on the surface of the bacteria as demonstrated by flow cytometry and immunofluorescence microscopy. The engineered bacteria can capture HIV-1 particles via surface-binding and inhibit HIV-1 infection in cell culture. - Highlights: • Designed single-chain VRC01 antibody was demonstrated to bind HIV-1 envelope gp120. • Single-chain VRC01 antibody was successfully displayed on the surface of E. coli. • Engineered bacteria can absorb HIV-1 particles and prevent HIV-1 infection in cell culture

  6. Complicated catheter-associated urinary tract infections due to Escherichia coli and Proteus mirabilis.

    Science.gov (United States)

    Jacobsen, S M; Stickler, D J; Mobley, H L T; Shirtliff, M E

    2008-01-01

    Catheter-associated urinary tract infections (CAUTIs) represent the most common type of nosocomial infection and are a major health concern due to the complications and frequent recurrence. These infections are often caused by Escherichia coli and Proteus mirabilis. Gram-negative bacterial species that cause CAUTIs express a number of virulence factors associated with adhesion, motility, biofilm formation, immunoavoidance, and nutrient acquisition as well as factors that cause damage to the host. These infections can be reduced by limiting catheter usage and ensuring that health care professionals correctly use closed-system Foley catheters. A number of novel approaches such as condom and suprapubic catheters, intermittent catheterization, new surfaces, catheters with antimicrobial agents, and probiotics have thus far met with limited success. While the diagnosis of symptomatic versus asymptomatic CAUTIs may be a contentious issue, it is generally agreed that once a catheterized patient is believed to have a symptomatic urinary tract infection, the catheter is removed if possible due to the high rate of relapse. Research focusing on the pathogenesis of CAUTIs will lead to a better understanding of the disease process and will subsequently lead to the development of new diagnosis, prevention, and treatment options.

  7. A prospective study of children with first acute sumptomatic E.coli urinary tract infections

    International Nuclear Information System (INIS)

    Tappin, D.M; Murphy, A.V.; Mocan, H.; Shaw, R.; Beattie, T.J.; McAllister, T.A.; Mackenzie, J.R.

    1989-01-01

    Between 1985 and 1987 102 children, age 0-14 years, presented with a first acute symptomatic E. coli urinary tract infection. Investigations included early 99m technetium dimercaptosuccinic acid (DMSA) scan, ultrasonography, micturating cysto-urethrography and indirect voiding radionuclide cystography using 99m Tc DTPA. Follow-up DMSA scan was carried out after 6 months. Twenty-one of 102 of initial DMSA studies showed diminished uptake of radionuclide and 12 showed cortical scarring. Twenty-nine patients had significant vesicoureteral relux. The finding of diminished uptake on the initial scan was significantly associated with fever, systemic upset, length of symptoms and a peripheral blood leucocytosis. In addition the finding was associated with fever and loin pain in the older child. Both diminished uptake and scarring were more common in refluxing kidney units. We propose that, in children with UTI, diminished uptake on early DMSA scan localises infection in the renal parenchyma

  8. Phylogenetic grouping and pathotypic comparison of urine and fecal Escherichia coli isolates from children with urinary tract infection

    Directory of Open Access Journals (Sweden)

    Masoumeh Navidinia

    2014-06-01

    Full Text Available The aim of this study was to investigate the phylogenetic background and to assess hlyD (involved in the secretion of haemolysin A and intll (encoding a class 1 integrase in Escherichia coli isolates derived from urinary and fecal specimens. A total of 200 E. coli isolates was collected from patients presenting with urinary tract infection (UTI during September 2009 to September 2010 and screened for hlyD and intll genes by polymerase chain reaction (PCR. Phylogenetic analysis showed that E. coli is composed of four main phylogenetic groups (A, B1, B2 and D and that uropathogenic E. coli (UPEC isolates mainly belong to groups B2 (54% and D (34% whereas group A (44% and D (26% are predominant among commensal E. coli isolates. In this study, hlyD was present in 26% of UPEC and 2% of commensal E. coli isolates. However, hemolytic activity was detected for 42% of UPEC and 6% of commensal E. coli isolates (p < 0.05. intll gene was more frequently expressed in UPEC (24% in comparison with commensal E. coli isolates (12%. Resistance to aztreonam, co-trimoxazole and cefpodoxime were frequently found among UPEC isolates whereas commensal E. coli isolates were commonly resistant to co-trimoxazole, nalidixic acid and cefotaxime. Concluding, a considerable difference between UPEC and commensal E. coli isolates was observed regarding their phylogenetic groups, presence of class 1 integron and hlyD gene, hemolysin activity and resistance pattern. The detection of class 1 integrons and hlyD gene was higher among UPEC compared with commensal E. coli isolates. These findings may contribute for a better understanding of the factors involved in the pathogenesis of UPEC.

  9. Metabolic investigation of host/pathogen interaction using MS2-infected Escherichia coli

    Directory of Open Access Journals (Sweden)

    Jain Rishi

    2009-12-01

    Full Text Available Abstract Background RNA viruses are responsible for a variety of illnesses among people, including but not limited to the common cold, the flu, HIV, and ebola. Developing new drugs and new strategies for treating diseases caused by these viruses can be an expensive and time-consuming process. Mathematical modeling may be used to elucidate host-pathogen interactions and highlight potential targets for drug development, as well providing the basis for optimizing patient treatment strategies. The purpose of this work was to determine whether a genome-scale modeling approach could be used to understand how metabolism is impacted by the host-pathogen interaction during a viral infection. Escherichia coli/MS2 was used as the host-pathogen model system as MS2 is easy to work with, harmless to humans, but shares many features with eukaryotic viruses. In addition, the genome-scale metabolic model of E. coli is the most comprehensive model at this time. Results Employing a metabolic modeling strategy known as "flux balance analysis" coupled with experimental studies, we were able to predict how viral infection would alter bacterial metabolism. Based on our simulations, we predicted that cell growth and biosynthesis of the cell wall would be halted. Furthermore, we predicted a substantial increase in metabolic activity of the pentose phosphate pathway as a means to enhance viral biosynthesis, while a break down in the citric acid cycle was predicted. Also, no changes were predicted in the glycolytic pathway. Conclusions Through our approach, we have developed a technique of modeling virus-infected host metabolism and have investigated the metabolic effects of viral infection. These studies may provide insight into how to design better drugs. They also illustrate the potential of extending such metabolic analysis to higher order organisms, including humans.

  10. Abortive Intestinal Infection With an Escherichia coli-Shigella flexneri Hybrid Strain

    Science.gov (United States)

    Formal, Samuel B.; LaBrec, E. H.; Kent, T. H.; Falkow, S.

    1965-01-01

    Formal, Samuel B., (Walter Reed Army Institute of Research, Washington, D.C.), E. H. LaBrec, T. H. Kent, and S. Falkow. Abortive intestinal infection with an Escherichia coli-Shigella flexneri hybrid strain. J. Bacteriol. 89:1374–1382. 1965.—The mechanism of the apparent loss of virulence of an Escherichia coli-Shigella flexneri hybrid strain was studied. The parent Shigella strain caused a fatal enteric infection when fed to starved guinea pigs, and signs of dysentery followed its oral administration to monkeys. The hybrid strain failed to produce any apparent symptoms when fed to either of these species. The parent strain was shown to invade the intestinal mucosa of starved guinea pigs. This caused a severe inflammatory reaction in the lamina propria, which progressed to ulceration of the intestinal epithelium and resulted in death of the animal. The hybrid strain also invaded the intestinal mucosa and produced an inflammatory reaction. In this case, the inflammatory reaction subsided, the intestine returned to normal within 4 days after challenge, and the animal survived. Both fluorescent-antibody techniques and in vivo growth studies have shown that the hybrid strain can not maintain itself in the intestinal mucosa. Preliminary studies have indicated that a similar situation also exists in the monkey. It is concluded that the virulence of dysentery bacilli rests not only in the capacity to reach the lamina propria, but also in the ability to multiply in this region. Images PMID:14293011

  11. Mechanisms of ion-bombardment-induced DNA transfer into bacterial E. coli cells

    Energy Technology Data Exchange (ETDEWEB)

    Yu, L.D., E-mail: yuld@thep-center.org [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Phanchaisri, B. [Institute of Science and Technology Research, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Singkarat, S. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2014-05-01

    Highlights: • Ion bombardment could induce DNA transfer into E. coli cells. • The DNA transfer induction depended on ion energy and fluence. • The mechanism was associated with the bacterial cell envelope structure. • A mechanism phase diagram was proposed to summarize the mechanism. - Abstract: As a useful ion beam biotechnology, ion-bombardment-induced DNA transfer into bacterial Escherichia coli (E. coli) cells has been successfully operated using argon ions. In the process ion bombardment of the bacterial cells modifies the cell envelope materials to favor the exogenous DNA molecules to pass through the envelope to enter the cell. The occurrence of the DNA transfer induction was found ion energy and fluence dependent in a complex manner. At ion energy of a few keV and a few tens of keV to moderate fluences the DNA transfer could be induced by ion bombardment of the bacterial cells, while at the same ion energy but to high fluences DNA transfer could not be induced. On the other hand, when the ion energy was medium, about 10–20 keV, the DNA transfer could not be induced by ion bombardment of the cells. The complexity of the experimental results indicated a complex mechanism which should be related to the complex structure of the bacterial E. coli cell envelope. A phase diagram was proposed to interpret different mechanisms involved as functions of the ion energy and fluence.

  12. Mechanisms of ion-bombardment-induced DNA transfer into bacterial E. coli cells

    International Nuclear Information System (INIS)

    Yu, L.D.; Sangwijit, K.; Prakrajang, K.; Phanchaisri, B.; Thongkumkoon, P.; Thopan, P.; Singkarat, S.; Anuntalabhochai, S.

    2014-01-01

    Highlights: • Ion bombardment could induce DNA transfer into E. coli cells. • The DNA transfer induction depended on ion energy and fluence. • The mechanism was associated with the bacterial cell envelope structure. • A mechanism phase diagram was proposed to summarize the mechanism. - Abstract: As a useful ion beam biotechnology, ion-bombardment-induced DNA transfer into bacterial Escherichia coli (E. coli) cells has been successfully operated using argon ions. In the process ion bombardment of the bacterial cells modifies the cell envelope materials to favor the exogenous DNA molecules to pass through the envelope to enter the cell. The occurrence of the DNA transfer induction was found ion energy and fluence dependent in a complex manner. At ion energy of a few keV and a few tens of keV to moderate fluences the DNA transfer could be induced by ion bombardment of the bacterial cells, while at the same ion energy but to high fluences DNA transfer could not be induced. On the other hand, when the ion energy was medium, about 10–20 keV, the DNA transfer could not be induced by ion bombardment of the cells. The complexity of the experimental results indicated a complex mechanism which should be related to the complex structure of the bacterial E. coli cell envelope. A phase diagram was proposed to interpret different mechanisms involved as functions of the ion energy and fluence

  13. Short communication: Antimicrobial efficacy of intramammary treatment with a novel biphenomycin compound against Staphylococcus aureus, Streptococcus uberis, and Escherichia coli-induced mouse mastitis.

    Science.gov (United States)

    Demon, Dieter; Breyne, Koen; Schiffer, Guido; Meyer, Evelyne

    2013-01-01

    Bovine mastitis undermines udder health, jeopardizes milk production, and entails prohibitive costs, estimated at $2 billion per year in the dairy industry of the United States. Despite intensive research, the dairy industry has not managed to eradicate the 3 major bovine mastitis-inducing pathogens: Staphylococcus aureus, Streptococcus uberis, and Escherichia coli. In this study, the antimicrobial efficacy of a newly formulated biphenomycin compound (AIC102827) was assessed against intramammary Staph. aureus, Strep. uberis, and E. coli infections, using an experimental mouse mastitis model. Based on its effective and protective doses, AIC102827 applied into the mammary gland was most efficient to treat Staph. aureus, but also adequately reduced growth of Strep. uberis or E. coli, indicating its potential as a broad-spectrum candidate to treat staphylococcal, streptococcal, and coliform mastitis in dairy cattle. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  14. Development and Efficacy Assessment of an Enteric Coated Porous Tablet Loaded With F4 Fimbriae for Oral Vaccination of Piglets against F4+ Escherichia coli Infections.

    Science.gov (United States)

    Srivastava, Atul; Gowda, D V; Madhunapantula, SubbaRao V; Siddaramaiah

    2016-01-01

    Enterotoxigenic Escherichia coli (ETEC) infection is one of the major causes contributing to the development of diarrhoea and mortality in new born, suckling and newly weaned piglets. To date, no preventive/treatment strategy showed promising results, which could be due to the lack of potent vaccines, and/or due to the development of resistance of ETEC to antibiotics. Therefore, in the present investigation, a novel porous sodium alginate (SA) tablet formulation loaded with F4 fimbriae antigen was developed and tested for efficacy against ETEC infections in piglet models. Precompression parameters of the powder mixes and post compression parameters of tablets have been evaluated and results were found to be satisfactory. Loading of F4 fimbrial antigens into the tablets was achieved by inducing pores in the tablets via the sublimation of camphor followed by incubation with purified F4 fimbriae. The loaded tablets have been coated with Eudragit L100 to protect the F4 fimbriae from (a) highly acidic gastric environment; (b) proteolytic cleavage by pepsin; and (c) to promote subsequent release in the intestine. Evaluation of developed F4 fimbrial tablets in a Pig model demonstrated induction of mucosal immunity, and a significant reduction of F4+ E. coli in faeces. Therefore, F4 fimbriae loaded porous tablets could be a novel oral vaccination candidate to induce mucosal and systemic immunity against ETEC infections.

  15. Co-infection of turkeys with Escherichia coli (O78) and H6N1 avian influenza virus.

    Science.gov (United States)

    Umar, Sajid; Delverdier, Maxence; Delpont, Mattias; Belkasmi, Sakhia F Z; Teillaud, Angélique; Bleuart, Céline; Pardo, Isabelle; El Houadfi, Mohammed; Guérin, Jean-Luc; Ducatez, Mariette F

    2018-03-28

    Respiratory diseases are responsible for major economic losses in poultry farms. While in most cases a single pathogen is not alone responsible for the clinical outcome, the impact of co-infections is not well known, especially in turkeys. The purpose of this study was to assess the possible synergism between Escherichia coli (O78) and low pathogenic avian influenza virus (LPAIV, H6N1), in the turkey model. Four-week-old commercial turkeys were inoculated with either H6N1, O78 or both agents simultaneously or three days apart. We have established an experimental infection model of turkeys using aerosolization that better mimics field infections. Birds were observed clinically and swabbed on a daily basis. Necropsies were performed at 4 and 14 days post single or dual inoculation and followed by histological and immunohistochemical analyses. Combined LPAIV/E. coli infections resulted in more severe clinical signs, were associated with higher mortality and respiratory organ lesions (mucous or fibrinous exudative material in lungs and air sacs), in comparison with the groups given single infections (P  0.05) respiratory signs were observed in turkeys of the E. coli followed by H6N1 inoculated group. Microscopic lesions and immunohistochemical staining supported clinical and macroscopic findings. Efficient virus and bacteria replication was observed in all inoculated groups. E. coli and H6N1 thus exercise an additive or synergistic pathogenic effect in the reproduction of respiratory disease.

  16. Role of UV-inducible proteins in repair of various wild-type Escherichia coli cells

    International Nuclear Information System (INIS)

    Sedliakova, M.; Slezarikova, V.; Brozmanova, J.; Masek, F.; Bayerova, V.

    1980-01-01

    3 wild-type strains of E. coli, namely K12 AB2497, B/r WP2 and 15 555-7, proficient in excision and post-replication repair, differ markedly in their UV resistance. To elucidate this difference, the influence was investigated of induction by application of inducing fluence (IF) before lethal fluence (LF) on repair processes after LF. In cells distinguished by low UV resistance (E. coli 15 555-7; E. coli B/r WP2), dimer excision was less complete in cultures irradiated with IF + LF than in cultures irradiated with LF only. The highly resistant E. coli K12 AB2497 performed complete excision both after IF + LF or after LF alone. All 3 types of cell survived better after IF + LF than after LF only. Because, in most strains so far investigated, the application of IF reduced dimer excision and increased survival, dimer excision per se does not appear important for survival. We conclude that the rate and completeness of dimer excision can serve as a measure of efficiency of the excision system whose action is necessary for repair of another lesion. Cells of all investigated strains could not resume DNA replication and died progressively when irradiated with LF and post-incubated with chloramphenicol (LF CAP + ). Thus, it appears that inducible proteins are necessary for repair in all wild-type E. coli cells given with potentially lethal doses of UV irradiation. (orig.)

  17. Temperature sensitivity of the penicillin-induced autolysis mechanism in nongrowing cultures of Escherichia coli.

    OpenAIRE

    Kusser, W; Ishiguro, E E

    1987-01-01

    The effect of incubation temperature on the ampicillin-induced autolysis of nongrowing Escherichia coli was determined. The autolysis mechanisms in amino acid-deprived relA mutant cells treated with chloramphenicol were temperature sensitive. This temperature-sensitive autolysis was demonstrated in three independent ways: turbidimetric determinations, viable cell counts, and solubilization of radiolabeled peptidoglycan.

  18. A Selected Lactobacillus rhamnosus Strain Promotes EGFR-Independent Akt Activation in an Enterotoxigenic Escherichia coli K88-Infected IPEC-J2 Cell Model

    OpenAIRE

    Zhang, Wei; Zhu, Yao-Hong; Yang, Jin-Cai; Yang, Gui-Yan; Zhou, Dong; Wang, Jiu-Feng

    2015-01-01

    Enterotoxigenic Escherichia coli (ETEC) are important intestinal pathogens that cause diarrhea in humans and animals. Although probiotic bacteria may protect against ETEC-induced enteric infections, the underlying mechanisms are unknown. In this study, porcine intestinal epithelial J2 cells (IPEC-J2) were pre-incubated with and without Lactobacillus rhamnosus ATCC 7469 and then exposed to F4+ ETEC. Increases in TLR4 and NOD2 mRNA expression were observed at 3 h after F4+ ETEC challenge, but t...

  19. Endocytosis-inducer adhesins produced by enteropathogenic serogroups of Escherichia coli participate on bacterial attachment to infant enterocytes

    Directory of Open Access Journals (Sweden)

    João Ramos Costa Andrade

    1987-03-01

    Full Text Available Enteropathogenic E. coli (EPEC infection of Hep-2 cells preoceeds through bacterial attachment to cell surface and internalization of adhered bacteria. EPEC attachment is a prerequisite for cell infection and is mediated by adhesins that recognize carbohydrate-containing receptors on cell membrane. Such endocytosis-inducer adhesins (EIA also promote EPEC binding to infant enterocytes, suggesting that EIA may have an important role on EPEC gastroenteritis.A infecção de células Hep-2 por E. coli enteropatogênicas (ECEP implica na aderência bacteriana e posterior interiorização dos microrganismos aderidos por um mecanismo de endocitose. A aderência das ECEP é pré-requisito para a infecção e é mediada por adesinas que reconhecem receptores inibidos por certas oses na membrana celular. Tais "adesinas indutoras da endocitose" (AIE também promovem a ligação bacteriana a enterócitos obtidos do intestino delgado de lactente, sugerindo que as AIE possam desempenhar algum papel nas diarréias causadas por ECEP.

  20. Choosing the correct empirical antibiotic for urinary tract infection in pediatric: Surveillance of antimicrobial susceptibility pattern of Escherichia coli by E-Test method.

    OpenAIRE

    Iraj Sedighi; Abbas Solgi; Ali Amanati; Mohammad Yousef Alikhani

    2014-01-01

    Background and Objectives Urinary Tract Infections (UTIs) are of the most common bacterial diseases worldwide. We investigate the antibiotic susceptibility patterns of Escherichia coli (E. coli) strains isolated from pediatric patients with community acquired urinary tract infection (UTI) to find a clinical guidance for choosing a right empirical antibiotic in these patients. Materials and Methods In this cross sectional study, 100 urine specimens which were positive for E. coli had been inve...

  1. The changing pattern of antimicrobial resistance within 42,033 Escherichia coli isolates from nosocomial, community and urology patient-specific urinary tract infections, Dublin, 1999-2009.

    LENUS (Irish Health Repository)

    Cullen, Ivor M

    2012-04-01

    To investigate the changing pattern of antimicrobial resistance in Escherichia coli urinary tract infection over an eleven year period, and to determine whether E. coli antibiotic resistance rates vary depending on whether the UTI represents a nosocomial, community acquired or urology patient specific infection.

  2. Identification of E.coli O157:H7 in Intestinal and Urinary Tract Infection in Samawah City .

    Directory of Open Access Journals (Sweden)

    Mouna Akeel Hamed Al-Oebady

    2017-02-01

    Full Text Available This study was conducted to isolate E.coli O157: H7 as an important zoonotic pathogen from 150 samples (75 bloody stools and 75 urine samples of patients at many age groups range from one to 50 years old and for both sexes were collected from patients suffering from diarrhea and urinary tract infection who attend the Samawah Teaching Hospital for pediatrics and Gynecology of AL-Muthanna Governorate. The results revealed that 120 out of 150 were positive to E.coli O157:H7 at a percentage (80%. The number of E. coli isolates in bloody stool were 67(89.3% and urine samples were 53(70.6% gave positive results to E.coli O157:H7 .

  3. Frequency-dependent ultrasound-induced transformation in E. coli.

    Science.gov (United States)

    Deeks, Jeremy; Windmill, James; Agbeze-Onuma, Maduka; Kalin, Robert M; Argondizza, Peter; Knapp, Charles W

    2014-12-01

    Ultrasound-enhanced gene transfer (UEGT) is continuing to gain interest across many disciplines; however, very few studies investigate UEGT efficiency across a range of frequencies. Using a variable frequency generator, UEGT was tested in E. coli at six ultrasonic frequencies. Results indicate frequency can significantly influence UEGT efficiency positively and negatively. A frequency of 61 kHz improved UEGT efficiency by ~70 % higher, but 99 kHz impeded UEGT to an extent worse than no ultrasound exposure. The other four frequencies (26, 133, 174, and 190 kHz) enhanced transformation compared to no ultrasound, but efficiencies did not vary. The influence of frequency on UEGT efficiency was observed across a range of operating frequencies. It is plausible that frequency-dependent dynamics of mechanical and chemical energies released during cavitational-bubble collapse (CBC) are responsible for observed UEGT efficiencies.

  4. The Relationship Between Class I and II Integrons and Antibiotic Resistance Among Escherichia coli Isolates From Urinary Tract Infections

    Directory of Open Access Journals (Sweden)

    Farshad Nojoomi

    2018-05-01

    Full Text Available Objective: the aim of this study was determination of antibiotic resistance profile, investigation of class I and II integrons among Escherichia coli (E. coli isolates from urinary tract infections. This study was conducted for the investigation of the prevalence of class I and II Integrons among E. coli Isolates from urinary tract infections. Materials and Methods: A total of 100 E. coli clinical isolates were collected from urinary tract infections in Borujerd city, Iran, from… to …. All the isolates were identified with standard laboratory procedures as described everywhere. The antibiotic susceptibility profile was conducted against adopted antibiotic disks following CLSI 2016 guidelines. All the isolates were enrolled in the PCR technique for the presence of class I and II integrons. Results: the highest resistance was against amoxicillin (72%, ciprofloxacin (69%, nalidixic acid (55% and tetracycline (51%. The prevalence of class I and II integrons was 31% and 21%, respectively. A significant relation was observed between resistance to trimethoprim-sulfamethoxazole (p<0.001, nalidixic acid (p<0.01 and tetracycline (p<0.005 with the presence of class I integron. The rate of class I integron in the E. coli isolates was high, possibly playing a role in the spread of multidrug resistant isolates. Conclusion: considering the significant relation observed between the presence of class I integron among multidrug-resistant isolates, establishment implementation of proper procedures to control and suitable treatment strategies in hospitals seems essential for the prevention of more spread of these isolates.

  5. Noise-induced Min phenotypes in E. coli.

    Directory of Open Access Journals (Sweden)

    David Fange

    2006-06-01

    Full Text Available The spatiotemporal oscillations of the Escherichia coli proteins MinD and MinE direct cell division to the region between the chromosomes. Several quantitative models of the Min system have been suggested before, but no one of them accounts for the behavior of all documented mutant phenotypes. We analyzed the stochastic reaction-diffusion kinetics of the Min proteins for several E. coli mutants and compared the results to the corresponding deterministic mean-field description. We found that wild-type (wt and filamentous (ftsZ- cells are well characterized by the mean-field model, but that a stochastic model is necessary to account for several of the characteristics of the spherical (rodA- and phospathedylethanolamide-deficient (PE- phenotypes. For spherical cells, the mean-field model is bistable, and the system can get trapped in a non-oscillatory state. However, when the intrinsic noise is considered, only the experimentally observed oscillatory behavior remains. The stochastic model also reproduces the change in oscillation directions observed in the spherical phenotype and the occasional gliding of the MinD region along the inner membrane. For the PE- mutant, the stochastic model explains the appearance of randomly localized and dense MinD clusters as a nucleation phenomenon, in which the stochastic kinetics at low copy number causes local discharges of the high MinD(ATP to MinD(ADP potential. We find that a simple five-reaction model of the Min system can explain all documented Min phenotypes, if stochastic kinetics and three-dimensional diffusion are accounted for. Our results emphasize that local copy number fluctuation may result in phenotypic differences although the total number of molecules of the relevant species is high.

  6. Biochemical studies in experimentally Escherichia coli infected broiler chicken supplemented with neem (Azadirachta indica leaf extract

    Directory of Open Access Journals (Sweden)

    Vikash Sharma

    2015-11-01

    Full Text Available Aim: An experimental study was conducted on 192-day-old broiler chicks for evaluating the effect of 10% neem leaf extract (NLE supplementationon biochemical parameters in chickens experimentally infected with Escherichia coli O78 at 107 CFU/0.5 ml at 7 days of age. Materials and Methods: The 192-day-old broiler chicks were procured. These chicks were divided into two groups (A and B containing 96 birds each on the 1st day. Diet of all the chicks of Group A was supplemented with 10%NLE in water, whereas chicks of Group B were given feed and water devoid of NLE supplementation throughout the experiment. After rearing for 1 week, chicks of both the groups (A and B were again divided into two subgroups (Group A into A1 and A2 and Group B into B1 and B2 of 54 and 42 birds, respectively. At the age of 7 days all the chicks of groups A1 and B1 were injected with E. coli O78 at 107 CFU/0.5 ml intraperitoneally. Blood samples were collected from six chicks from each group at day 0, 2, 4, 7, 14, 21, 28 days post-infection and serum was separated for biochemical studies. Results: There was a significant increase in serum alanine transaminase (ALT, aspartate transaminase (AST, lactate dehydrogenase (LDH activities, globulin concentration and a decrease in total protein (TP, albumin concentrations, and alkaline phosphatase (ALP activity in both the infected groups. However, the changes in biochemical values, i.e., ALT, AST, LDH, ALP, TP, albumin, and globulin wereof lower magnitude in NLE supplemented group suggesting hepatoprotective and cardioprotective effect of NLE. Conclusions: Fromthe present study, it is reasonable to conclude that significant increase in the value of ALT, AST, LDH, globulin, and significant decrease in the value of ALP, TP, and albumin was of lower magnitude in supplemented infected group (A1 as compared to non-supplemented infected group (B1 suggesting hepatoprotective and cardioprotective effect of NLE.

  7. Women with symptoms of a urinary tract infection but a negative urine culture: PCR-based quantification of Escherichia coli suggests infection in most cases.

    Science.gov (United States)

    Heytens, S; De Sutter, A; Coorevits, L; Cools, P; Boelens, J; Van Simaey, L; Christiaens, T; Vaneechoutte, M; Claeys, G

    2017-09-01

    Our objective was to examine whether or not women with symptoms of a urinary tract infection but with a negative culture (20%-30%) do have an infection. We performed quantitative PCR (qPCR) for Escherichia coli and Staphylococcus saprophyticus, on top of a standard culture, in urine samples from 220 women with dysuria and/or frequency and/or urgency and from 86 women without symptoms. For symptomatic women, qPCR was also carried out for four sexually transmitted agents. In the symptomatic group, 80.9% (178/220) of the urine cultures were positive for any uropathogen and 95.9% (211/220) were E. coli qPCR-positive. For the control group, cultures for E. coli and E. coli qPCR were positive in, respectively, 10.5% (9/86) and 11.6% (10/86). In the symptomatic group, qPCR yielded 19 positive samples for S. saprophyticus qPCR, one positive sample for Mycoplasma genitalium and one for Trichomonas vaginalis. These findings suggest that almost all women with typical urinary complaints and a negative culture still have an infection with E. coli. Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  8. Immunization of pregnant cows with Shiga toxin-2 induces high levels of specific colostral antibodies and lactoferrin able to neutralize E. coli O157:H7 pathogenicity.

    Science.gov (United States)

    Albanese, Adriana; Sacerdoti, Flavia; Seyahian, E Abril; Amaral, Maria Marta; Fiorentino, Gabriela; Fernandez Brando, Romina; Vilte, Daniel A; Mercado, Elsa C; Palermo, Marina S; Cataldi, Angel; Zotta, Elsa; Ibarra, Cristina

    2018-03-20

    E. coli O157:H7 is a foodborne pathogen responsible for bloody diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS). The objective of the present work was to evaluate the ability of colostral IgG obtained from Stx2-immunized cows to prevent against E. coli O157:H7 infection and Stx2 cytotoxicity. Hyperimmune colostrum (HC) was obtained from cows intramuscularly immunized with inactivated Stx2 or vehicle for controls. Colostral IgG was purified by affinity chromatography. Specific IgG antibodies against Stx2 and bovine lactoferrin (bLF) levels in HC and the corresponding IgG (HC-IgG/bLF) were determined by ELISA. The protective effects of HC-IgG/bLF against Stx2 cytotoxicity and adhesion of E. coli O157:H7 and its Stx2-negative mutant were analyzed in HCT-8 cells. HC-IgG/bLF prevention against E. coli O157:H7 was studied in human colon and rat colon loops. Protection against a lethal dose of E. coli O157:H7 was evaluated in a weaned mice model. HC-IgG/bLF showed high anti-Stx2 titers and high bLF levels that were able to neutralize the cytotoxic effects of Stx2 in vitro and in vivo. Furthermore, HC-IgG/bLF avoided the inhibition of water absorption induced by E. coli O157:H7 in human colon and also the pathogenicity of E. coli O157:H7 and E. coli O157:H7Δstx2 in rat colon loops. Finally, HC-IgG/bLF prevented in a 100% the lethality caused by E. coli O157:H7 in a weaned mice model. Our study suggests that HC-IgG/bLF have protective effects against E. coli O157:H7 infection. These beneficial effects may be due to specific anti-Stx2 neutralizing antibodies in combination with high bLF levels. These results allow us to consider HC-IgG/bLF as a nutraceutical tool which could be used in combination with balanced supportive diets to prevent HUS. However further studies are required before recommendations can be made for therapeutic and clinical applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Prostate specific antigen enhances the innate defence of prostatic epithelium against Escherichia coli infection.

    Science.gov (United States)

    Townes, Claire L; Ali, Ased; Gross, Naomi; Pal, Deepali; Williamson, Stuart; Heer, Rakesh; Robson, Craig N; Pickard, Robert S; Hall, Judith

    2013-10-01

    This study investigated whether the increase in serum prostate specific antigen (PSA) typically seen during male urinary tract infection (UTI) is incidental or reflects an innate defence mechanism of the prostate. The protective roles of the whey-acid-motif-4-disulphide core (WFDC) proteins, secretory leukoproteinase inhibitor (SLPI) and WFDC2, in the prostate were also examined. UTI recurrence was assessed retrospectively in men following initial UTI by patient interview. PSA, SLPI, and WFDC2 gene expression were assessed using biopsy samples. LNCaP and DU145 in vitro prostate cell models were utilized to assess the effects of an Escherichia coli challenge on PSA and WFDC gene expression, and bacterial invasion of the prostate epithelium. The effects of PSA on WFDC antimicrobial properties were studied using recombinant peptides and time-kill assays. Men presenting with PSA >4 ng/ml at initial UTI were less likely to have recurrent (r) UTI than those with PSA prostatic epithelium, and the PSA and SLPI proteins co-localized in vivo. Challenging LNCaP (PSA-positive) cells with E. coli increased PSA, SLPI, and WFDC2 gene expression (P prostate innate defences. Copyright © 2013 Wiley Periodicals, Inc.

  10. Prevalence of antimicrobial resistant Escherichia coli from patients with suspected urinary tract infection in primary care, Denmark

    DEFF Research Database (Denmark)

    Cordoba, Gloria; Holm, Anne; Hansen, Frank

    2017-01-01

    Background: Escherichia coli is the most common pathogen causing Urinary Tract Infections (UTI). Data from the current National Surveillance program in Denmark (DANMAP) may not accurately represent the prevalence of resistant E. coli in primary care, because only urine samples from complicated......: Observational study carried out from December 2014 to December 2015. Thirty-nine general practices from The Capital Region of Denmark included adult patients with urinary tract symptoms and suspected UTI. All urine samples were sent to the central laboratory Statens Serum Institut (SSI). Significant bacteriuria...... 485 (96%) patients. According to the European Urinalysis Standards, 261 (54%) patients had positive bacteriuria. The most common uropathogen in patients with uncomplicated (uUTI) and complicated (cUTI) urinary tract infection was E. coli 105 (69%) and 76 (70%), respectively. Eighty-two (45%) of 181 E...

  11. The E. coli Global Regulator DksA Reduces Transcription during T4 Infection

    Directory of Open Access Journals (Sweden)

    Jennifer Patterson-West

    2018-06-01

    Full Text Available Bacteriophage T4 relies on host RNA polymerase to transcribe three promoter classes: early (Pe, requires no viral factors, middle (Pm, requires early proteins MotA and AsiA, and late (Pl, requires middle proteins gp55, gp33, and gp45. Using primer extension, RNA-seq, RT-qPCR, single bursts, and a semi-automated method to document plaque size, we investigated how deletion of DksA or ppGpp, two E. coli global transcription regulators, affects T4 infection. Both ppGpp0 and ΔdksA increase T4 wild type (wt plaque size. However, ppGpp0 does not significantly alter burst size or latent period, and only modestly affects T4 transcript abundance, while ΔdksA increases burst size (2-fold without affecting latent period and increases the levels of several Pe transcripts at 5 min post-infection. In a T4motAam infection, ΔdksA increases plaque size and shortens latent period, and the levels of specific middle RNAs increase due to more transcription from Pe’s that extend into these middle genes. We conclude that DksA lowers T4 early gene expression. Consequently, ΔdksA results in a more productive wt infection and ameliorates the poor expression of middle genes in a T4motAam infection. As DksA does not inhibit Pe transcription in vitro, regulation may be indirect or perhaps requires additional factors.

  12. Metabolic Requirements of Escherichia coli in Intracellular Bacterial Communities during Urinary Tract Infection Pathogenesis

    Directory of Open Access Journals (Sweden)

    Matt S. Conover

    2016-04-01

    Full Text Available Uropathogenic Escherichia coli (UPEC is the primary etiological agent of over 85% of community-acquired urinary tract infections (UTIs. Mouse models of infection have shown that UPEC can invade bladder epithelial cells in a type 1 pilus-dependent mechanism, avoid a TLR4-mediated exocytic process, and escape into the host cell cytoplasm. The internalized UPEC can clonally replicate into biofilm-like intracellular bacterial communities (IBCs of thousands of bacteria while avoiding many host clearance mechanisms. Importantly, IBCs have been documented in urine from women and children suffering acute UTI. To understand this protected bacterial niche, we elucidated the transcriptional profile of bacteria within IBCs using microarrays. We delineated the upregulation within the IBC of genes involved in iron acquisition, metabolism, and transport. Interestingly, lacZ was highly upregulated, suggesting that bacteria were sensing and/or utilizing a galactoside for metabolism in the IBC. A ΔlacZ strain displayed significantly smaller IBCs than the wild-type strain and was attenuated during competitive infection with a wild-type strain. Similarly, a galK mutant resulted in smaller IBCs and attenuated infection. Further, analysis of the highly upregulated gene yeaR revealed that this gene contributes to oxidative stress resistance and type 1 pilus production. These results suggest that bacteria within the IBC are under oxidative stress and, consistent with previous reports, utilize nonglucose carbon metabolites. Better understanding of the bacterial mechanisms used for IBC development and establishment of infection may give insights into development of novel anti-virulence strategies.

  13. [Aspects of the antimicrobial resistence profile in infections with Escherichia coli and Klebsiella pneumoniae in diabetic patients].

    Science.gov (United States)

    Petrovici, Cristina G; Dorobăţ, Carmen; Matei, Mioara; Teodor, Andra; Luca, V; Miftode, Egidia

    2011-01-01

    Infections in diabetic patient remains an important cause of morbidity and mortality, triggering and maintaining a prolonged metabolic imbalance. Emergence of extented spectrum beta-lactmase (ESBL) in Escherichia coli and Klebsiella pneumoniae is a major concern, because of the atypical manner infection acts in this group of imunodepressed patients and also for the limited therapeutic solutions. For this reason we have evaluated the profile of antimicrobial resistance of these pathogens in both diabetic and non diabetic patients. The aim of this study was to evaluate, in a retrospective case control study, the antibiotic susceptibility pattern in isolates of E. coli and Klebsiella spp. from different biological products in 49 diabetics and 150 non-diabetics admitted in The Clinical Hospital of Infectious Diseases Iaşi over a period of two years. Most of strains of E. coli and Klebsiella spp. ESBL positive were found in uroculture. Significant differences in E. coli resistance rate between diabetics and nondiabetics were noted for amoxicillin-clavulanic acid and ciprofloxacin (31,4% vs.13,98%, p=0,04, respectively 52,9% vs. 24,46%, p=0,004). More isolates of ESBL positive K. pneumoniae were found in diabetic patients (50% vs. 24%). Ciprofloxacin resistance of K. pneumoniae was significantly higher in diabetics (75% vs 39%; p=0,05). There was no resistance in E. coli and K. pneumoniae isolates to imipenem in the diabetic group. The high resistance rate to quinolones and 3rd generation cefalosporins limits their use for the treatment of Escherichia coli and K. pneumoniae infections. Other alternatives for empiric therapy in community and nosocomial-acquired infections in diabetic patient remains carbapenems, aminoglycosides and colimycin.

  14. Determinants of Antimicrobial Resistance in Escherichia coli Strains Isolated from Faeces and Urine of Women with Recurrent Urinary Tract Infections

    NARCIS (Netherlands)

    den Heijer, Casper D. J.; Beerepoot, Mariëlle A. J.; Prins, Jan M.; Geerlings, Suzanne E.; Stobberingh, Ellen E.

    2012-01-01

    For women with recurrent urinary tract infections (rUTI), the contribution of antibiotic use versus patient-related factors in determining the presence of antimicrobial resistance in faecal and urinary Escherichia coli, obtained from the same patient population, has not been assessed yet. Within the

  15. Feeding of Lactobacillus sobrius reduces Escherichia coli F4 levels in the gut and promotes growth of infected piglets

    NARCIS (Netherlands)

    Konstantinov, S.R.; Smidt, H.; Akkermans, A.D.L.; Casini, L.; Trevisi, P.; Mazzoni, M.; Filippi, de S.; Bosi, P.; Vos, de W.M.

    2008-01-01

    The microbial community in the guts of mammals is often seen as an important potential target in therapeutic and preventive interventions. The aim of the present study was to determine whether enterotoxigenic Escherichia coli (ETEC) F4 infection in young animals might be counteracted by a probiotic

  16. Bovine natural killer cells are present in Escherichia coli infected mammary gland tissue and show antimicrobial activity in vitro

    NARCIS (Netherlands)

    Sipka, Anja; Pomeroy, Brianna; Klaessig, Suzanne; Schukken, Ynte

    2016-01-01

    Natural killer (NK) cells are early responders in bacterial infections but their role in bovine mastitis has not been characterized. For the first time, we show the presence of NK cells (NKp46+/CD3−) in bovine mammary gland tissue after an intramammary challenge with Escherichia (E.) coli. A small

  17. Radiation-induced mutagenicity and lethality in tryptophan-requiring auxotrophs of escherichia coli

    International Nuclear Information System (INIS)

    Xu Rong; Qian Hongwei; Yao Fenying; Gu Shuzhu; Xu Jiaxin; Bi Hekan; Liu Yuying

    1989-01-01

    Mutation and killing caused by X-ray radiation and 60 Co γ-ray radiation were studied in three different tryptophan-requiring auxotrophs (WP2, Wp2A, Cm 891) of Escherichia coli. These testers are sensitive to base pair substitution mutagens. Cm891 carries a R-factor and is more sensitive than WP2 and WP2A to radiation-induced mutation and lethality. The results of the study show that (1) ionizing radiation was mutagenic to E. coli, (2) the order of mutagenic sensitivity among three strains to ionizing radiation was Cm891 > WP2A > WP2, (3) the dose rate of γ-ray influences mutagenicity and lethalty of E. coli strain, (4) the toxicity and mutagenicity of γ-ray were similar to X-ray when Cm891 was tested, however, γ-ray was more toxic and mutagenic than X-ray to WP2A ang WP2

  18. Bacteriophage T4 Infection of Stationary Phase E. coli: Life after Log from a Phage Perspective

    Directory of Open Access Journals (Sweden)

    Elizabeth Martin Kutter

    2016-09-01

    Full Text Available Virtually all studies of phage infections investigate bacteria growing exponentially in rich media. In nature, however, phages largely encounter non-growing cells. Bacteria entering stationary phase often activate well-studied stress defense mechanisms that drastically alter the cell, facilitating its long-term survival. An understanding of phage-host interactions in such conditions is of major importance from both an ecological and therapeutic standpoint. Here, we show that bacteriophage T4 can efficiently bind to, infect and kill E. coli in stationary phase, both in the presence and absence of a functional stationary-phase sigma factor, and explore the response of T4-infected stationary phase cells to the addition of fresh nutrients 5 or 24 hours after that infection. An unexpected new mode of response has been identified. Hibernation mode is a persistent but reversible dormant state in which the infected cells make at least some phage enzymes, but halt phage development until appropriate nutrients become available before producing phage particles. Our evidence indicates that the block in hibernation mode occurs after the middle-mode stage of phage development; host DNA breakdown and the incorporation of the released nucleotides into phage DNA indicate that the enzymes of the nucleotide synthesizing complex, under middle-mode control, have been made and assembled into a functional state. Once fresh glucose and amino acids become available, the standard lytic infection process rapidly resumes and concentrations of up to 1011 progeny phage (an average of about 40 phage per initially-present cell are produced. All evidence is consistent with the hibernation-mode control point lying between middle mode and late mode T4 gene expression. We have also observed a scavenger response, where the infecting phage takes advantage of whatever few nutrients are available to produce small quantities of progeny within 2 to 5 hours after infection. The scavenger

  19. Cytotoxic Necrotizing Factor-1 (CNF1) does not promote E. coli infection in a murine model of ascending pyelonephritis.

    Science.gov (United States)

    Michaud, Jason E; Kim, Kwang Sik; Harty, William; Kasprenski, Matthew; Wang, Ming-Hsien

    2017-05-25

    Urinary tract infections (UTI) are among the most common and costly infections in both hospitalized and ambulatory patients. Uropathogenic E. coli (UPEC) represent the majority of UTI isolates and are a diverse group of bacteria that utilize a variety of virulence factors to establish infection of the genitourinary tract. The virulence factor cytotoxic necrotizing factor-1 (CNF1) is frequently expressed in clinical UPEC isolates. To date, there have been conflicting reports on the role of CNF1 in the pathogenesis of E. coli urinary tract infections. We examined the importance of CNF1 in a murine ascending kidney infection/ pyelonephritis model by performing comparative studies between a clinical UPEC isolate strain and a CNF1-deletion mutant. We found no alterations in bacterial burden with the loss of CNF1, whereas loss of the virulence factor fimH decreased bacterial burdens. In addition, we found no evidence that CNF1 contributed to the recruitment of inflammatory infiltrates in the kidney or bladder in vivo. While further examination of CNF-1 may reveal a role in UTI pathogenesis, our data casts doubt on the role of CNF-1 in the pathogenesis of UPEC UTI. As with other infections, different models and approaches are needed to elucidate the contribution of CNF1 to E. coli UTI.

  20. Children with moderate-high infection with Entamoeba coli have higher percentage of body and abdominal fat than non-infected children.

    Science.gov (United States)

    Zavala, G A; García, O P; Campos-Ponce, M; Ronquillo, D; Caamaño, M C; Doak, C M; Rosado, J L

    2016-12-01

    Intestinal parasites, virus and bacterial infections are positively associated with obesity and adiposity in vitro and in animal models, but conclusive evidence of this relationship in humans is lacking. The aim of this cross-sectional study was to determine differences in adiposity between infected and non-infected children, with a high prevalence of intestinal parasitic infection and obesity. A total of 296 school-aged children (8.0 ± 1.5 years) from a rural area in Querétaro, Mexico, participated in this study. Anthropometry (weight, height and waist circumference) and body fat (DXA) were measured in all children. A fresh stool sample was collected from each child and analysed for parasites. Questionnaires related to socioeconomic status and clinical history were completed by caretakers. Approximately 11% of the children were obese, and 19% were overweight. The overall prevalence of infection was 61%. Ascaris lumbricoides was the most prevalent soil transmitted helminth (16%) followed by hookworm. Entamoeba coli was the predominant protozoa (20%) followed by Endolimax nana, Balantidium coli, Entamoeba histolytica/dispar, Iodamoeba bütschlii and Giardia lamblia. Children with moderate-heavy infection of E. coli had significantly higher waist circumference, waist-to-height ratio, body and abdominal fat than children not infected or with light-intensity infection (p fat deposition and thereby have long-term consequences on human health. Further studies are needed to better understand if E. coli contributes directly to fat deposition and possible mechanisms. © 2015 World Obesity Federation.

  1. Low-energy plasma immersion ion implantation to induce DNA transfer into bacterial E. coli

    Energy Technology Data Exchange (ETDEWEB)

    Sangwijit, K. [Biotechnology Unit, University of Phayao, Muang, Phayao 56000 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Sarapirom, S. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Bang Khen, Chiang Mai 50290 (Thailand); Pitakrattananukool, S. [School of Science, University of Phayao, Muang, Phayao 56000 (Thailand); Anuntalabhochai, S. [Biotechnology Unit, University of Phayao, Muang, Phayao 56000 (Thailand)

    2015-12-15

    Plasma immersion ion implantation (PIII) at low energy was for the first time applied as a novel biotechnology to induce DNA transfer into bacterial cells. Argon or nitrogen PIII at low bias voltages of 2.5, 5 and 10 kV and fluences ranging from 1 × 10{sup 12} to 1 × 10{sup 17} ions/cm{sup 2} treated cells of Escherichia coli (E. coli). Subsequently, DNA transfer was operated by mixing the PIII-treated cells with DNA. Successes in PIII-induced DNA transfer were demonstrated by marker gene expressions. The induction of DNA transfer was ion-energy, fluence and DNA-size dependent. The DNA transferred in the cells was confirmed functioning. Mechanisms of the PIII-induced DNA transfer were investigated and discussed in terms of the E. coli cell envelope anatomy. Compared with conventional ion-beam-induced DNA transfer, PIII-induced DNA transfer was simpler with lower cost but higher efficiency.

  2. [Effect of eicosapentaenoic acid on mRNA expression of tight junction protein ZO-1 in intestinal epithelial cells after Escherichia coli LF82 infection].

    Science.gov (United States)

    Hao, Li-Jun; Lin, Yan; Zhang, Wei; Tian, Jiao; Wang, Ya; Chen, Peng-De; Hu, Chong-Kang; Zeng, Ling-Chao; Yang, Jie; Wang, Bao-Xi; Jiang, Xun

    2017-06-01

    To investigate the change in the expression of tight junction protein ZO-1 in intestinal epithelial cells (Caco-2 cells) and the protective effect of eicosapentaenoic acid (EPA) after adherent-invasive Escherichia coli (E.coli) LF82 infection. The Caco-2 cell line was used to establish an in vitro model of tight junction of intestinal epithelial cells. Caco-2 cells were divided into EPA treatment groups (0, 25, 50, 100, and 200 μmol/L EPA) and EPA (0, 25, 50, 100, and 200 μmol/L EPA)+E.coli LF82 treatment (0, 6, and 12 hours) groups. A microscope was used to observe the morphological characteristics of the cells. MTT assay was used to determine the cell growth curve. The activity of alkaline phosphatase (ALP) at both sides of the cell membrane was compared to evaluate the Caco-2 cell model. MTT assay and flow cytometry were used to investigate the effects of different concentrations of EPA on the survival rate and apoptosis rate of Caco-2 cells. RT-qPCR was used to measure the mRNA expression of ZO-1 in Caco-2 cells after EPA and/or E.coli LF82 treatment. ELISA was used to measure the change in the level of tumor necrosis factor-α (TNF-α) in culture supernatant. After EPA treatment (25 and 50 μmol/L), the proliferation of Caco-2 cells was induced in a dose-dependent manner. The survival rates of the cells were significantly higher than those in the control group (PE.coli LF82 treatment groups had decreasing mRNA expression of ZO-1 in Caco-2 cells over the time of treatment and had significantly lower mRNA expression of ZO-1 than the untreated group (PE.coli LF82 and 25 or 50 μmol/L EPA for 6 or 12 hours showed an increase in the mRNA expression of ZO-1 with the increasing concentration of EPA, as well as significantly higher mRNA expression of ZO-1 than the Caco-2 cells treated with E.coli LF82 alone (PE.coli LF82 alone for 6 or 12 hours had increasing secretion of TNF-α over the time of treatment and had significantly higher secretion than the untreated

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

    African Journals Online (AJOL)

    DJFLEX

    VARIATIONS IN VIRULENCE OF THREE (3) ESCHERICHIA COLI. SEROTYPES CONFIRMED IN ... ows are susceptible to E. coli infection because. E. coli exist in the .... Coli infections in mice: A laboratory animal model for research in.

  4. Pathological alterations in respiratory system during co-infection with low pathogenic avian influenza virus (H9N2 and Escherichia coli in broiler chickens

    Directory of Open Access Journals (Sweden)

    Jaleel Shahid

    2017-09-01

    Full Text Available Introduction: Despite the advancements in the field, there is a lack of data when it comes to co-infections in poultry. Therefore, this study was designed to address this issue. Material and Methods: Broiler birds were experimentally infected with E. coli (O78 and low pathogenic avian influenza (LPAI strain, alone or in combination. The experimental groups were negative control. Results: The infected birds showed most severe clinical signs in E. coli+LPAI group along with a significant decrease in weight and enhanced macroscopic and microscopic pathological lesions. The survival rate was 60%, 84%, and 100% in birds inoculated with E. coli+LPAI, E. coli, and LPAI virus alone, respectively. The results showed that experimental co-infection with E. coli and H9N2 strain of LPAI virus increased the severity of clinical signs, mortality rate, and gross lesions. The HI titre against LPAI virus infection in the co-infected group was significantly higher than the HI titre of LPAI group, which may indicate that E. coli may promote propagation of H9N2 LPAI virus by alteration of immune response. Conclusion: The present study revealed that co-infection with E. coli and H9N2 LPAI virus caused more serious synergistic pathogenic effects and indicates the role of both pathogens as complicating factors in poultry infections.

  5. Alkylation Induced DNA Repair and Mutagenesis in Escherichia coli.

    Science.gov (United States)

    1987-11-23

    unrepaired 3-methyladenine in DNA 29 2.4.1 Cytotoxic effects of persisting m3A in DNA 30 2.4.2 Mutagenic bypass synthesis of depurinat ,d DNA 30 3 CONCLUDING...induced by a single exposure to the ca’rcinogen N- methyl-N- nitrosourea (MNU) due to activation of the malignant Ha-ras-i locus. Analysis of the induced...ing CO:A uolymerase I for repair synthesis . Since DNA polymerase I would be required to complete repair after the in~uial activity of TagII, we tested

  6. Detection and Classification of Live and Dead Escherichia coli by Laser-Induced Breakdown Spectroscopy

    Science.gov (United States)

    Sivakumar, P.; Fernández-Bravo, A.; Taleh, L.; Biddle, J.F.

    2015-01-01

    Abstract A common goal for astrobiology is to detect organic materials that may indicate the presence of life. However, organic materials alone may not be representative of currently living systems. Thus, it would be valuable to have a method with which to determine the health of living materials. Here, we present progress toward this goal by reporting on the application of laser-induced breakdown spectroscopy (LIBS) to study characteristics of live and dead cells using Escherichia coli (E. coli) strain K12 cells as a model organism since its growth and death in the laboratory are well understood. Our goal is to determine whether LIBS, in its femto- and/or nanosecond forms, could ascertain the state of a living organism. E. coli strain K12 cells were grown, collected, and exposed to one of two types of inactivation treatments: autoclaving and sonication. Cells were also kept alive as a control. We found that LIBS yields key information that allows for the discrimination of live and dead E. coli bacteria based on ionic shifts reflective of cell membrane integrity. Key Words: E. coli—Trace elements—Live and dead cells—Laser-induced breakdown spectroscopy—Atomic force microscopy. Astrobiology 15, 144–153. PMID:25683088

  7. Persistent Transmissible Gastroenteritis Virus Infection Enhances Enterotoxigenic Escherichia coli K88 Adhesion by Promoting Epithelial-Mesenchymal Transition in Intestinal Epithelial Cells.

    Science.gov (United States)

    Xia, Lu; Dai, Lei; Yu, Qinghua; Yang, Qian

    2017-11-01

    Transmissible gastroenteritis virus (TGEV) is a coronavirus characterized by diarrhea and high morbidity rates, and the mortality rate is 100% in piglets less than 2 weeks old. Pigs infected with TGEV often suffer secondary infection by other pathogens, which aggravates the severity of diarrhea, but the mechanisms remain unknown. Here, we hypothesized that persistent TGEV infection stimulates the epithelial-mesenchymal transition (EMT), and thus enterotoxigenic Escherichia coli (ETEC) can more easily adhere to generating cells. Intestinal epithelial cells are the primary targets of TGEV and ETEC infections. We found that TGEV can persistently infect porcine intestinal columnar epithelial cells (IPEC-J2) and cause EMT, consistent with multiple changes in key cell characteristics. Infected cells display fibroblast-like shapes; exhibit increases in levels of mesenchymal markers with a corresponding loss of epithelial markers; have enhanced expression levels of interleukin-1β (IL-1β), IL-6, IL-8, transforming growth factor β (TGF-β), and tumor necrosis factor alpha (TNF-α) mRNAs; and demonstrate increases in migratory and invasive behaviors. Additional experiments showed that the activation of the phosphatidylinositol 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK) signaling pathways via TGF-β is critical for the TGEV-mediated EMT process. Cellular uptake is also modified in cells that have undergone EMT. TGEV-infected cells have higher levels of integrin α5 and fibronectin and exhibit enhanced ETEC K88 adhesion. Reversal of EMT reduces ETEC K88 adhesion and inhibits the expression of integrin α5 and fibronectin. Overall, these results suggest that TGEV infection induces EMT in IPEC-J2 cells, increasing the adhesion of ETEC K88 in the intestine and facilitating dual infection. IMPORTANCE Transmissible gastroenteritis virus (TGEV) causes pig diarrhea and is often followed by secondary infection by other pathogens. In this study, we showed

  8. Zinc blocks SOS-induced antibiotic resistance via inhibition of RecA in Escherichia coli.

    Science.gov (United States)

    Bunnell, Bryan E; Escobar, Jillian F; Bair, Kirsten L; Sutton, Mark D; Crane, John K

    2017-01-01

    Zinc inhibits the virulence of diarrheagenic E. coli by inducing the envelope stress response and inhibiting the SOS response. The SOS response is triggered by damage to bacterial DNA. In Shiga-toxigenic E. coli, the SOS response strongly induces the production of Shiga toxins (Stx) and of the bacteriophages that encode the Stx genes. In E. coli, induction of the SOS response is accompanied by a higher mutation rate, called the mutator response, caused by a shift to error-prone DNA polymerases when DNA damage is too severe to be repaired by canonical DNA polymerases. Since zinc inhibited the other aspects of the SOS response, we hypothesized that zinc would also inhibit the mutator response, also known as hypermutation. We explored various different experimental paradigms to induce hypermutation triggered by the SOS response, and found that hypermutation was induced not just by classical inducers such as mitomycin C and the quinolone antibiotics, but also by antiviral drugs such as zidovudine and anti-cancer drugs such as 5-fluorouracil, 6-mercaptopurine, and azacytidine. Zinc salts inhibited the SOS response and the hypermutator phenomenon in E. coli as well as in Klebsiella pneumoniae, and was more effective in inhibiting the SOS response than other metals. We then attempted to determine the mechanism by which zinc, applied externally in the medium, inhibits hypermutation. Our results show that zinc interferes with the actions of RecA, and protects LexA from RecA-mediated cleavage, an early step in initiation of the SOS response. The SOS response may play a role in the development of antibiotic resistance and the effect of zinc suggests ways to prevent it.

  9. Zinc blocks SOS-induced antibiotic resistance via inhibition of RecA in Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Bryan E Bunnell

    Full Text Available Zinc inhibits the virulence of diarrheagenic E. coli by inducing the envelope stress response and inhibiting the SOS response. The SOS response is triggered by damage to bacterial DNA. In Shiga-toxigenic E. coli, the SOS response strongly induces the production of Shiga toxins (Stx and of the bacteriophages that encode the Stx genes. In E. coli, induction of the SOS response is accompanied by a higher mutation rate, called the mutator response, caused by a shift to error-prone DNA polymerases when DNA damage is too severe to be repaired by canonical DNA polymerases. Since zinc inhibited the other aspects of the SOS response, we hypothesized that zinc would also inhibit the mutator response, also known as hypermutation. We explored various different experimental paradigms to induce hypermutation triggered by the SOS response, and found that hypermutation was induced not just by classical inducers such as mitomycin C and the quinolone antibiotics, but also by antiviral drugs such as zidovudine and anti-cancer drugs such as 5-fluorouracil, 6-mercaptopurine, and azacytidine. Zinc salts inhibited the SOS response and the hypermutator phenomenon in E. coli as well as in Klebsiella pneumoniae, and was more effective in inhibiting the SOS response than other metals. We then attempted to determine the mechanism by which zinc, applied externally in the medium, inhibits hypermutation. Our results show that zinc interferes with the actions of RecA, and protects LexA from RecA-mediated cleavage, an early step in initiation of the SOS response. The SOS response may play a role in the development of antibiotic resistance and the effect of zinc suggests ways to prevent it.

  10. Avoidance of voiding cystourethrography in infants younger than 3 months with Escherichia coli urinary tract infection and normal renal ultrasound.

    Science.gov (United States)

    Pauchard, Jean-Yves; Chehade, Hassib; Kies, Chafika Zohra; Girardin, Eric; Cachat, Francois; Gehri, Mario

    2017-09-01

    Urinary tract infection (UTI) represents the most common bacterial infection in infants, and its prevalence increases with the presence of high-grade vesicoureteral reflux (VUR). However, voiding cystourethrography (VCUG) is invasive, and its indication in infants urinary E. coli infection. Adding a normal renal US finding decreased this probability to 1%. However, in the presence of non- E. coli bacteria, the probability of high-grade VUR was 26%, and adding an abnormal US finding increased further this probability to 55%. In infants aged 0-3 months with a first febrile UTI, the presence of E. coli and normal renal US findings allow to safely avoid VCUG. Performing VCUG only in infants with UTI secondary to non- E. coli bacteria and/or abnormal US would save many unnecessary invasive procedures, limit radiation exposure, with a very low risk (<1%) of missing a high-grade VUR. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  11. The ygaVP Genes of Escherichia coli Form a Tributyltin-Inducible Operon▿ †

    OpenAIRE

    Gueuné, Hervé; Durand, Marie-José; Thouand, Gérald; DuBow, Michael S.

    2008-01-01

    A tributyltin (TBT) luxAB transcriptional fusion in Escherichia coli revealed that a TBT-activated promoter is located upstream of two cotranscribed orphan genes, ygaV and ygaP. We demonstrate that transcription from the promoter upstream of ygaVP is constitutive in a ygaVP mutant, suggesting that YgaV is an autoregulated, TBT-inducible repressor.

  12. Changes in thermal nociceptive responses in dairy cows following experimentally induced Esherichia coli mastitis

    DEFF Research Database (Denmark)

    Rasmussen, Ditte B.; Fogsgaard, Katrine; Røntved, Christine Maria

    2011-01-01

    Mastitis is a high incidence disease in dairy cows. The acute stage is considered painful and inflammation can lead to hyperalgesia and thereby contribute to decreased welfare. The aim of this study was to examine changes in nociceptive responses toward cutaneous nociceptive laser stimulation (NLS......) in dairy cows with experimentally induced Escherichia coli mastitis, and correlate behavioral changes in nociceptive responses to clinical and paraclinical variables....

  13. Agricultural, socioeconomic and environmental variables as risks for human verotoxigenic Escherichia coli (VTEC) infection in Finland.

    Science.gov (United States)

    Jalava, Katri; Ollgren, Jukka; Eklund, Marjut; Siitonen, Anja; Kuusi, Markku

    2011-10-18

    Verotoxigenic E. coli (VTEC) is the cause of severe gastrointestinal infection especially among infants. Between 10 and 20 cases are reported annually to the National Infectious Disease Register (NIDR) in Finland. The aim of this study was to identify explanatory variables for VTEC infections reported to the NIDR in Finland between 1997 and 2006. We applied a hurdle model, applicable for a dataset with an excess of zeros. We enrolled 131 domestically acquired primary cases of VTEC between 1997 and 2006 from routine surveillance data. The isolated strains were characterized by virulence type, serogroup, phage type and pulsed-field gel electrophoresis. By applying a two-part Bayesian hurdle model to infectious disease surveillance data, we were able to create a model in which the covariates were associated with the probability for occurrence of the cases in the logistic regression part and the magnitude of covariate changes in the Poisson regression part if cases do occur. The model also included spatial correlations between neighbouring municipalities. The average annual incidence rate was 4.8 cases per million inhabitants based on the cases as reported to the NIDR. Of the 131 cases, 74 VTEC O157 and 58 non-O157 strains were isolated (one person had dual infections). The number of bulls per human population and the proportion of the population with a higher education were associated with an increased occurrence and incidence of human VTEC infections in 70 (17%) of 416 of Finnish municipalities. In addition, the proportion of fresh water per area, the proportion of cultivated land per area and the proportion of low income households with children were associated with increased incidence of VTEC infections. With hurdle models we were able to distinguish between risk factors for the occurrence of the disease and the incidence of the disease for data characterised by an excess of zeros. The density of bulls and the proportion of the population with higher education were

  14. Effects of Lactobacillus kefiranofaciens M1 isolated from kefir grains on enterohemorrhagic Escherichia coli infection using mouse and intestinal cell models.

    Science.gov (United States)

    Chen, Y P; Lee, T Y; Hong, W S; Hsieh, H H; Chen, M J

    2013-01-01

    A potential probiotic strain, Lactobacillus kefiranofaciens M1, was previously isolated from kefir grains, which are used to manufacture the traditional fermented drink kefir. The aim of this study was to investigate the effects of Lb. kefiranofaciens M1 on enterohemorrhagic Escherichia coli (EHEC) infection, using mice and intestinal cell models. BALB/c mice were daily administrated with either phosphate buffered saline or Lb. kefiranofaciens M1 at 2×10(8) cfu/mouse per day intragastrically for 7 d. Intragastric challenges with EHEC (2×10(9) cfu/mouse) were conducted on d 0, 4, and 7 after treatment. Administration of Lb. kefiranofaciens M1 was able to prevent EHEC infection-induced symptoms, intestinal damage, renal damage, bacterial translocation, and Shiga toxin penetration. Furthermore, the mucosal EHEC-specific IgA responses were increased after Lb. kefiranofaciens M1 administration in the EHEC-infected mouse system. Additionally, in vitro, Lb. kefiranofaciens M1 was shown to have a protective effect on Caco-2 intestinal epithelial cells and Caco-2 intestinal epithelial cell monolayers; the bacteria limited EHEC-induced cell death and reduced the loss of epithelial integrity. These findings support the potential of Lb. kefiranofaciens M1 treatment as an approach to preventing EHEC infection and its effects. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  15. Influence of very short patch mismatch repair on SOS inducing lesions after aminoglycoside treatment in Escherichia coli.

    Science.gov (United States)

    Baharoglu, Zeynep; Mazel, Didier

    2014-01-01

    Low concentrations of aminoglycosides induce the SOS response in Vibrio cholerae but not in Escherichia coli. In order to determine whether a specific factor present in E. coli prevents this induction, we developed a genetic screen where only SOS inducing mutants are viable. We identified the vsr gene coding for the Vsr protein of the very short patch mismatch repair (VSPR) pathway. The effect of mismatch repair (MMR) mutants was also studied. We propose that lesions formed upon aminoglycoside treatment are preferentially repaired by VSPR without SOS induction in E. coli and by MMR when VSPR is impaired. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  16. Immuno-pathological studies on broiler chicken experimentally infected with Escherichia coli and supplemented with neem (Azadirachta indica leaf extract

    Directory of Open Access Journals (Sweden)

    Vikash Sharma

    2016-07-01

    Full Text Available Aim: The present study was conducted to evaluate the effects of neem leaf extract (NLE supplementation on immunological response and pathology of different lymphoid organs in experimentally Escherichia coli challenged broiler chickens. Materials and Methods: For this study, we procured 192-day-old broiler chicks from local hatchery and divided them into Groups A and Group B containing 96 birds each on the first day. Chicks of Group A were supplemented with 10% NLE in water, whereas chicks of Group B were not supplemented with NLE throughout the experiment. At 7th day of age, chicks of Group A were divided into A1 and A2 and Group B into B1 and B2 with 54 and 42 chicks, respectively, and chicks of Groups A1 and B1 were injected with E. coli O78 at 107 colony-forming units/0.5 ml intraperitoneally. Six chicks from each group were sacrificed at 0, 2, 4, 7, 14, 21, and 28 days post infection; blood was collected and thorough post-mortem examination was conducted. Tissue pieces of spleen and bursa of Fabricius were collected in 10% buffered formalin for histopathological examination. Serum was separated for immunological studies. Result: E. coli specific antibody titer was significantly higher in Group A1 in comparison to Group B1. Delayed-type hypersensitivity response against 2,4 dinirochlorobenzene (DNCB antigen was significantly higher in Group A1 as compared to Group B1. Pathological studies revealed that E. coli infection caused depletion of lymphocytes in bursa of Fabricius and spleen. Severity of lesions in Group A1 was significantly lower in comparison to Group B1. Conclusion: 10% NLE supplementation enhanced the humoral as well as cellular immune responses attributed to its immunomodulatory property in experimentally E. coli infected broiler chicken.

  17. Immuno-pathological studies on broiler chicken experimentally infected with Escherichia coli and supplemented with neem (Azadirachta indica) leaf extract.

    Science.gov (United States)

    Sharma, Vikash; Jakhar, K K; Dahiya, Swati

    2016-07-01

    The present study was conducted to evaluate the effects of neem leaf extract (NLE) supplementation on immunological response and pathology of different lymphoid organs in experimentally Escherichia coli challenged broiler chickens. For this study, we procured 192-day-old broiler chicks from local hatchery and divided them into Groups A and Group B containing 96 birds each on the first day. Chicks of Group A were supplemented with 10% NLE in water, whereas chicks of Group B were not supplemented with NLE throughout the experiment. At 7(th) day of age, chicks of Group A were divided into A1 and A2 and Group B into B1 and B2 with 54 and 42 chicks, respectively, and chicks of Groups A1 and B1 were injected with E. coli O78 at 10(7) colony-forming units/0.5 ml intraperitoneally. Six chicks from each group were sacrificed at 0, 2, 4, 7, 14, 21, and 28 days post infection; blood was collected and thorough post-mortem examination was conducted. Tissue pieces of spleen and bursa of Fabricius were collected in 10% buffered formalin for histopathological examination. Serum was separated for immunological studies. E. coli specific antibody titer was significantly higher in Group A1 in comparison to Group B1. Delayed-type hypersensitivity response against 2,4 dinirochlorobenzene (DNCB) antigen was significantly higher in Group A1 as compared to Group B1. Pathological studies revealed that E. coli infection caused depletion of lymphocytes in bursa of Fabricius and spleen. Severity of lesions in Group A1 was significantly lower in comparison to Group B1. 10% NLE supplementation enhanced the humoral as well as cellular immune responses attributed to its immunomodulatory property in experimentally E. coli infected broiler chicken.

  18. Risk factors for extended-spectrum b-lactamases-producing Escherichia coli urinary tract infections in a tertiary hospital

    Directory of Open Access Journals (Sweden)

    María Dolores Alcántar-Curiel

    2015-09-01

    Full Text Available Objective. To assess the risks factors for urinary tract infections (UTIs caused by Extended-Spectrum Beta-Lactamases (ESBLs-producing E. coli and the molecular characterization of ESBLs. Materials and methods. A case-control study was performed to identify risk factors in consecutively recruited patients with UTIs caused by ESBLs or non-ESBLs-producing E. coli in a tertiary hospital in Mexico. Results. ESBLs-producing E. coli were isolated from 22/70 (31% patients with E. coli UTIs over a three month period. All isolates were resistant to cephalosporins and quinolones but susceptible to carbapenems, amikacin and nitrofurantoin. Prior antibiotic treatment with more than two antibiotic families (OR=6.86; 95%CI 1.06-157.70; p=0.028, recurrent symptomatic UTIs (OR=5.60; 95%CI 1.88-17.87; p=0.001 and previous hospitalization (OR=5.06; 95%CI 1.64-17.69;p=0.002 were significant risk factors. Sixteen isolates harbored the beta-lactamase (blaCTX-M-15 gene and five the blaTEM-1 gene. Conclusions. One of every three patients presented UTIs with ESBLs-producing beta-lactams and fluoroquinolone resistant E. coli. Risk factors and resistance patterns must be taken into account for developing antibiotic use policies in these settings

  19. Bovine Leukemia Virus Infection in Dairy Cattle: Effect on Serological Response to Immunization against J5 Escherichia coli Bacterin

    Directory of Open Access Journals (Sweden)

    Ronald J. Erskine

    2011-01-01

    Full Text Available Thirteen bovine leukemia virus- (BLV- negative and 22 BLV-positive Holstein cows were immunized with J5 Escherichia coli bacterin at dry off, three weeks before calving, during the second week after calving, and three weeks after the third immunization. Serum was collected before the initial immunization, immediately before the third and fourth immunizations, and 21 days after the fourth immunization. Anti-J5 E. coli IgM, IgG1, and IgG2 titers were determined by ELISA. Anti-J5 E. coli IgM titers did not differ significantly (P=.98 between groups. Increases in anti-J5 E. coli IgG1 titers were higher in the BLV-negative cows (P=.057. Geometric mean anti-J5 E. coli IgG2 titers increased fourfold in the BLV-negative cows, which was significantly higher (P=.007 than the twofold increase in the BLV-positive cows. Cattle infected with BLV may have impaired serologic responses following immunization with J5 bacterin, and response may differ according to antibody isotype.

  20. Serological evidence of asymptomatic infections during Escherichia coli O104:H4 outbreak in Germany in 2011.

    Directory of Open Access Journals (Sweden)

    Yanina Balabanova

    Full Text Available INTRODUCTION: The largest known outbreak caused by a rare hybrid strain of Shiga toxin-producing E.coli (STEC and enteroaggregative E. coli (EAEC (E.coli O104:H4 of serotype O104:H4 occurred in Germany in 2011. Fenugreek sprouts acted as a transmission vehicle and were widely consumed in the outbreak area at the time of the epidemic. In total 3,842 people developed a clinical illness caused by this strain; however the rates of asymptomatic infections remain unclear. We aimed to develop a serological assay for detection of E.coli O104 LPS specific antibodies and to establish the post-outbreak levels of seropositivity among people with documented exposure to contaminated sprouts. RESULTS AND DISCUSSION: Developed serological assays (ELISA with 84% sensitivity, 63% specificity and Western Blot with 100% sensitivity, 82.5% specificity identified 33% (16/49 level of asymptomatic infection. Relatively small sample size and a significant time- lapse between the onset of symptoms and serum samples collection (appr. 8 weeks might explain the assay variability. No association was found between clinical or demographic characteristics and assay positivity. Larger studies are needed to understand the complexity of human immune response and factors influencing development of clinical symptoms. Development of intra-outbreak research plans will substantially aid the conduct of more thorough scientific investigation during an outbreak period.

  1. Study of Sensibility and Antimicrobial Resistance in Escherichia coli Isolated from Urinary Tract Infection in Tabriz City

    Directory of Open Access Journals (Sweden)

    Hamed Molaabaszadeh

    2013-09-01

    Full Text Available  Background & Objective: Urinary infection is one of the most prevalent infectious diseases, and Escherichia coli is the most important cause of urinary infections. This study was done with the aim of surveying the amount of susceptibility and resistance among the strains of Escherichia coli isolated from those who referred to the private laboratories in the Iranian city of Tabriz.   Materials & Methods: This survey was done periodically during the first 6 months of the year 2010. Samples were obtained in a sterile manner and were subjected to all necessary pathological tests. Evaluation of antibiotic susceptibility was conducted with disk diffusion standard method, and the results were analyzed.   Results: Totally, 5701 Escherichia coli strains were identified. The highest sensitivity to Imipenem was 90.95%, Nitrofurantoin 85.97%, and Cefotaxime 71.02% and the highest resistance to Ampicillin was 83.95%, Tetracycline 80.97%, and Co-trimoxazole 63.92%.   Conclusion: Our results suggest that the cause of the high resistance of Escherichia coli strains to Ampicillin and Tetracycline could be the consumption of these antibiotics. Therefore, abstaining from overuse of unnecessary antibiotics and production of new-generation and cost-effective antibiotics are recommend. 

  2. Effects of aging on endotoxin tolerance induced by lipopolysaccharides derived from Porphyromonas gingivalis and Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Ying Sun

    Full Text Available Periodontitis is a bacterially induced chronic inflammatory disease. Exposure of the host to periodontal pathogens and their virulence factors induces a state of hyporesponsiveness to subsequent stimulations, termed endotoxin tolerance. Aging has a profound effect on immune response to bacteria challenge. The aim of this study was to explore the effects of aging on endotoxin tolerance induced by Porphyromonas gingivalis (P. gingivalis lipopolysaccharide (LPS and Escherichia coli (E. coli LPS in murine peritoneal macrophages.We studied the cytokine production (TNF-α and IL-10 and Toll-like receptor 2, 4 (TLR2, 4 gene and protein expressions in peritoneal macrophages from young (2-month-old and middle-aged (12-month-old ICR mice following single or repeated P. gingivalis LPS or E. coli LPS stimulation. Pretreatment of peritoneal macrophages with P. gingivalis LPS or E. coli LPS resulted in a reduction in TNF-α production and an increase in IL-10 production upon secondary stimulation (p<0.05, and the markedly lower levels of TNF-α and higher levels of IL-10 were observed in macrophages from young mice compared with those from middle-aged mice (p<0.05. In addition, LPS restimulations also led to the significantly lower expression levels of TLR2, 4 mRNA and protein in macrophages from young mice (p<0.05.Repeated LPS stimulations triggered endotoxin tolerance in peritoneal macrophages and the ability to develop tolerance in young mice was more excellent. The impaired ability to develop endotoxin tolerance resulted from aging might be related to TLR2, 4 and might lead to the incontrollable periodontal inflammation in older adults.

  3. Royal Society of Tropical Medicine and Hygiene meeting at Manson House, London, 14 December 1995. Enteropathogenic Escherichia coli--mucosal infection models.

    Science.gov (United States)

    Frankel, G; Phillips, A D; Hicks, S; Dougan, G

    1996-01-01

    The formation of attaching and effacing (A/E) lesions is central to the pathogenesis of enteropathogenic Escherichia coli (EPEC)-mediated disease in humans and Citrobacter rodentium-mediated transmissible colonic hyperplasia in mice. Closely related outer membrane proteins, known as intimins, are required for formation of the A/E lesion by both EPEC and C. rodentium. In this study we found similar ultrastructural damage in small intestinal biopsies from an EPEC-infected child and large bowel specimens from C. rodentium-infected mice. The C. rodentium-infected large bowel biopsies revealed massive hyperplastic reactions and the infected human small intestinal biopsies showed an increase in total crypt cell number and mitotic index. EPEC-infected small intestinal organ cultures revealed bacteria adhering in a localized pattern and evidence of A/E lesions. Covaspheres coated with a biologically active cell-binding domain of intimin also adhered to cells in a localized fashion but did not induce the characteristic A/E lesions.

  4. Detection of mcr-1 encoding plasmid-mediated colistin-resistant Escherichia coli isolates from human bloodstream infection and imported chicken meat, Denmark 2015

    DEFF Research Database (Denmark)

    Hasman, H.; Hammerum, A. M.; Hansen, F.

    2015-01-01

    The plasmid-mediated colistin resistance gene, mcr-1, was detected in an Escherichia coli isolate from a Danish patient with bloodstream infection and in five E. coli isolates from imported chicken meat. One isolate from chicken meat belonged to the epidemic spreading sequence type ST131...

  5. Photorhabdus luminescens genes induced upon insect infection

    Directory of Open Access Journals (Sweden)

    Jung Kirsten

    2008-05-01

    Full Text Available Abstract Background Photorhabdus luminescens is a Gram-negative luminescent enterobacterium and a symbiote to soil nematodes belonging to the species Heterorhabditis bacteriophora. P.luminescens is simultaneously highly pathogenic to insects. This bacterium exhibits a complex life cycle, including one symbiotic stage characterized by colonization of the upper nematode gut, and a pathogenic stage, characterized by release from the nematode into the hemocoel of insect larvae, resulting in rapid insect death caused by bacterial toxins. P. luminescens appears to sense and adapt to the novel host environment upon changing hosts, which facilitates the production of factors involved in survival within the host, host-killing, and -exploitation. Results A differential fluorescence induction (DFI approach was applied to identify genes that are up-regulated in the bacterium after infection of the insect host Galleria mellonella. For this purpose, a P. luminescens promoter-trap library utilizing the mCherry fluorophore as a reporter was constructed, and approximately 13,000 clones were screened for fluorescence induction in the presence of a G. mellonella larvae homogenate. Since P. luminescens has a variety of regulators that potentially sense chemical molecules, like hormones, the screen for up-regulated genes or operons was performed in vitro, excluding physicochemical signals like oxygen, temperature or osmolarity as variables. Clones (18 were obtained exhibiting at least 2.5-fold induced fluorescence and regarded as specific responders to insect homogenate. In combination with a bioinformatics approach, sequence motifs were identified in these DNA-fragments that are similar to 29 different promoters within the P. luminescens genome. By cloning each of the predicted promoters upstream of the reporter gene, induction was verified for 27 promoters in vitro, and for 24 promoters in viable G. mellonella larvae. Among the validated promoters are some known

  6. Galleria mellonella infection model demonstrates high lethality of ST69 and ST127 uropathogenic E. coli.

    Directory of Open Access Journals (Sweden)

    Majed F Alghoribi

    Full Text Available Galleria mellonella larvae are an alternative in vivo model for investigating bacterial pathogenicity. Here, we examined the pathogenicity of 71 isolates from five leading uropathogenic E. coli (UPEC lineages using G. mellonella larvae. Larvae were challenged with a range of inoculum doses to determine the 50% lethal dose (LD50 and for analysis of survival outcome using Kaplan-Meier plots. Virulence was correlated with carriage of a panel of 29 virulence factors (VF. Larvae inoculated with ST69 and ST127 isolates (10(4 colony-forming units/larvae showed significantly higher mortality rates than those infected with ST73, ST95 and ST131 isolates, killing 50% of the larvae within 24 hours. Interestingly, ST131 isolates were the least virulent. We observed that ST127 isolates are significantly associated with a higher VF-score than isolates of all other STs tested (P≤0.0001, including ST69 (P<0.02, but one ST127 isolate (strain EC18 was avirulent. Comparative genomic analyses with virulent ST127 strains revealed an IS1 mediated deletion in the O-antigen cluster in strain EC18, which is likely to explain the lack of virulence in the larvae infection model. Virulence in the larvae was not correlated with serotype or phylogenetic group. This study illustrates that G. mellonella are an excellent tool for investigation of the virulence of UPEC strains. The findings also support our suggestion that the incidence of ST127 strains should be monitored, as these isolates have not yet been widely reported, but they clearly have a pathogenic potential greater than that of more widely recognised clones, including ST73, ST95 or ST131.

  7. Antibiotic sensitivity of escherichia coli isolated from urinary tract infection referred to Kermanshah central laboratory

    Directory of Open Access Journals (Sweden)

    Parviz Mohajeri

    2011-03-01

    Full Text Available Background: Escherichia coli (Ecoli has been considered as the most common agent of urinary tract infection in all regions. Recently, increased drug resistance has been lead to some problems in treatment related diseases. So, evaluation of resistance patterns of bacteria in each region could be a valuable guide for empirical treatment.Methods: All referred urine sample to Kermanshah Central Laboratory during 1998 that was reported positive to Ecoli were assessed. Susceptibility pattern to 19 antimicrobial agents was evaluated using Kirby Bauer method according to CLSI standards.Results: A total of 834 Ecoli isolated from 19,208 positive urine cultures. 84% of subjects were females and 16% males. Sensitivity rate for nitrofurantoin (84%, ceftizoxime (72%, norfloxacin (70%, cefotaxime (69%, Amikacin (66%, ciprofloxacin (65%, ceftriaxone (64%, ceftazidim (55% was higher than 50%. Sensitivity to nalidixic acid, cefexime, gentamicin, co-trimoxazole, ticarcillin, caphalexin, cephalotin, tetracycline, amoxicillin, amoxicillin clavulanate and ampicillin were determined less than 50%.Conclusion: Nitrofurantoin and ceftizoxime are currently effective against Ecoli, although an indiscriminate use of antibiotics should be avoided because of drug resistance probable. It seems that ampicillin could be excluded from routine sensitivity testing.

  8. Immune responses induced by co-infection with Capillaria hepatica in Clonorchis sinensis-infected rats.

    Science.gov (United States)

    Moon, E-K; Lee, S-H; Goo, T W; Quan, F-S

    2018-07-01

    Clonorchis sinensis and Capillaria hepatica are zoonotic parasites that mainly infect the liver and cause serious liver disorders. However, immunological parameters induced by co-infection with these parasites remain unknown. In this study, for the first time, we investigated immunological profiles induced by co-infection with C. hepatica (CH) in C. sinensis (CS)-infected rats (Sprague-Dawley). Rats were infected primarily with 50 metacercariae of C. sinensis; 4 weeks later, they were subsequently infected with 1000 infective C. hepatica eggs. Significantly higher levels of C. sinensis- or C. hepatica-specific IgG antibodies were found in the sera of rats. Interestingly, no cross-reacting antibody was observed between C. sinensis and C. hepatica infections. Significantly raised eosinophil levels were found in the blood of C. sinensis/C. hepatica co-infected rats (CS + CH) compared to the blood of rats infected singly with C. sinensis. Co-infected rats showed significantly higher levels of lymphocyte proliferation and cytokine production compared to a single C. sinensis infection. The worm burden of C. sinensis was significantly reduced in co-infected rats compared to the single C. sinensis infection. These results indicate that the eosinophils, lymphocyte proliferation and cytokine production induced by subsequent infection with C. hepatica in C. sinensis-infected rats might contribute to the observed C. sinensis worm reduction.

  9. The Role of Properdin in Zymosan- and Escherichia coli-Induced Complement Activation

    DEFF Research Database (Denmark)

    Harboe, Morten; Garred, Peter; Lindstad, Julie K

    2012-01-01

    Properdin is well known as an enhancer of the alternative complement amplification loop when C3 is activated, whereas its role as a recognition molecule of exogenous pathogen-associated molecular patterns and initiator of complement activation is less understood. We therefore studied the role...... of properdin in activation of complement in normal human serum by zymosan and various Escherichia coli strains. In ELISA, microtiter plates coated with zymosan induced efficient complement activation with deposition of C4b and terminal complement complex on the solid phase. Virtually no deposition of C4b...... cytometry was used to further explore whether properdin acts as an initial recognition molecule reacting directly with zymosan and three E. coli strains. Experiments reported by other authors were made with EGTA Mg(2+) buffer, permitting autoactivation of C3. We found inhibition by compstatin...

  10. Patch size and base composition of ultraviolet light-induced repair synthesis in toluenized Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Ishai, R; Sharon, R [Technion-Israel Inst. of Tech., Haifa

    1978-04-15

    Small patch repair in ultraviolet-irradiated Escherichia coli was saturated at deoxynucleoside triphosphate concentrations (approximately 2..mu..M of each dNTP) that are severly limiting for DNA replication. The low requirement of the repair process for dNTPs permitted direct demonstration of u.v.-induced DNA synthesis by incorporation of labelled dNTP and determination of its extent, base composition and patch size. It is concluded that DNA polymerase 1 is involved in small patch repair and that an average of 13 to 16 nucleotides are re-inserted per pyrimidine dimer excised. The average base composition of the repaired stretches adjacent to the dimers is similar to that of total E.coli DNA. An assay utilizing endogenous u.v.-specific endonuclease to determine dimer excision is described.

  11. Role of urinary cathelicidin LL-37 and human β-defensin 1 in uncomplicated Escherichia coli urinary tract infections

    DEFF Research Database (Denmark)

    Nielsen, Karen L; Dynesen, Pia; Larsen, Preben

    2014-01-01

    Cathelicidin (LL-37) and human β-defensin 1 (hBD-1) are important components of the innate defense in the urinary tract. The aim of this study was to characterize whether these peptides are important for developing uncomplicated Escherichia coli urinary tract infections (UTIs). This was investiga......Cathelicidin (LL-37) and human β-defensin 1 (hBD-1) are important components of the innate defense in the urinary tract. The aim of this study was to characterize whether these peptides are important for developing uncomplicated Escherichia coli urinary tract infections (UTIs......). This was investigated by comparing urinary peptide levels of UTI patients during and after infection to those of controls, as well as characterizing the fecal flora of participants with respect to susceptibility to LL-37 and in vivo virulence. Forty-seven UTI patients and 50 controls who had never had a UTI were...... included. Participants were otherwise healthy, premenopausal, adult women. LL-37 MIC levels were compared for fecal E. coli clones from patients and controls and were also compared based on phylotypes (A, B1, B2, and D). In vivo virulence was investigated in the murine UTI model by use of selected fecal...

  12. Active protein aggregates induced by terminally attached self-assembling peptide ELK16 in Escherichia coli

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    Zhou Bihong

    2011-02-01

    Full Text Available Abstract Background In recent years, it has been gradually realized that bacterial inclusion bodies (IBs could be biologically active. In particular, several proteins including green fluorescent protein, β-galactosidase, β-lactamase, alkaline phosphatase, D-amino acid oxidase, polyphosphate kinase 3, maltodextrin phosphorylase, and sialic acid aldolase have been successfully produced as active IBs when fused to an appropriate partner such as the foot-and-mouth disease virus capsid protein VP1, or the human β-amyloid peptide Aβ42(F19D. As active IBs may have many attractive advantages in enzyme production and industrial applications, it is of considerable interest to explore them further. Results In this paper, we report that an ionic self-assembling peptide ELK16 (LELELKLK2 was able to effectively induce the formation of cytoplasmic inclusion bodies in Escherichia coli (E. coli when attached to the carboxyl termini of four model proteins including lipase A, amadoriase II, β-xylosidase, and green fluorescent protein. These aggregates had a general appearance similar to the usually reported cytoplasmic inclusion bodies (IBs under transmission electron microscopy or fluorescence confocal microscopy. Except for lipase A-ELK16 fusion, the three other fusion protein aggregates retained comparable specific activities with the native counterparts. Conformational analyses by Fourier transform infrared spectroscopy revealed the existence of newly formed antiparallel beta-sheet structures in these ELK16 peptide-induced inclusion bodies, which is consistent with the reported assembly of the ELK16 peptide. Conclusions This has been the first report where a terminally attached self-assembling β peptide ELK16 can promote the formation of active inclusion bodies or active protein aggregates in E. coli. It has the potential to render E. coli and other recombinant hosts more efficient as microbial cell factories for protein production. Our observation might

  13. Cost effective purification of intein based syntetic cationic antimicrobial peptide expressed in cold shock expression system using salt inducible E. coli GJ1158

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    Seetha Ram Kotra

    2014-03-01

    Full Text Available Objective:Synthetic cationic antimicrobial peptide (SC-AMP is an important and upcoming therapeutic molecule against onventional antibiotics. In this study, an attempt was made to purify the SC-AMP without the enzymatic cleavage of the affinity tag, by using an intein-based system. Methods:The intein sequence was amplified from pTYB11 vector using PCR methodologies and the N-terminal of intein was ligated with SC-AMP. The designed construct, intein-SC-AMP was cloned into MCS region of cold shock expression vector, pCOLDI and the recombinant peptide was purified on a chitin affinity column by cleaving intein with 50 mM DTT without applying enzymatic cleavage. Later the peptide was quantified and its antibacterial activity of the purified peptide was studied using well diffusion method. Results: Initially, intein-SC-AMP was expressed as a fusion protein in both IPTG inducible E. coli BL21(DE3 and salt inducible E. coli GJ1158. Single step purification using CBD (chitin binding domain - intein tag in salt inducible E. coli GJ1158, yields the SC-AMP in the soluble form at a oncentration of 208 mg/L. The antibacterial activity and minimal inhibitory concentration (MIC of the purified SC-AMP was studied against both Gram positive and Gram negative microorganisms. Conclusion: For the first time, single step purification of soluble SC-AMP was carried out using chitin-binding domain affinity tag in salt inducible E. coli GJ1158 without an application of enzymatic cleavage. J Microbiol Infect Dis 2014;4(1:13-19

  14. Helminth infections induce immunomodulation : consequences and mechanisms

    NARCIS (Netherlands)

    Riet, Petronella Helena van

    2008-01-01

    Worldwide, more than a billion people are infected with helminths. These worm infections are chronic in nature and can lead to considerable morbidity. Immunologically these infections are interesting; chronic helminth infections are characterized by skewing towards a T helper 2 type response as well

  15. Antibiotic Resistance, RAPD- PCR Typing of Multiple Drug Resistant Strains of Escherichia Coli From Urinary Tract Infection (UTI).

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    Marialouis, Xavier Alexander; Santhanam, Amutha

    2016-03-01

    Global spreading of multidrug resistant strains of Escherichia coli is responsible for Urinary Tract Infection (UTI) which is a major health problem in of concern. Among the gram negative bacteria, the major contributors for UTI belongs to the family Enterobacteriaceae, which includes E. coli, Klebsiella, Citrobacter and Proteus. However, E. coli accounts for the major cause of Urinary tract infections (UTIs) and accounts for 75% to 90% of UTI isolates. The main aim of this study is to analyse the phylogenetic grouping of clinical isolates of UTI E. coli. In this study nearly 58 E. coli strains were isolated and confirmed through microbiological, biochemical characterization. The urine samples were collected from outpatients having symptoms of UTI, irrespective of age and sex in Tamil Nadu, India. The isolates were subjected to analyse for ESBL and AmpC β-lactamase production. To understand its genetic correlation, molecular typing was carried out using RAPD-PCR method. Here we noted phenotypically twenty seven isolates were positive for ESBL and seven for AmpC β-lactamase production. However, among the ESBL isolates higher sensitivity was noted for Nitrofurantoin and Cefoxitin. It is worth to note that the prevalence of UTIs was more common among female and elderly male. Phylogenetic grouping revealed the presence of 24 isolates belonged to B2 group followed by 19 isolates to group A, eight isolates to group B1 and Seven isolates to group D. Phenotypically most of the strains were positive for ESBL and showed high sensitivity for Nitrofurantoin and cefoxitin.

  16. An evaluation of E. coli in urinary tract infection in emergency department at KAMC in Riyadh, Saudi Arabia: retrospective study.

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    Alanazi, Menyfah Q; Alqahtani, Fulwah Y; Aleanizy, Fadilah S

    2018-02-09

    Urinary tract infection (UTIS) is a common infectious disease in which level of antimicrobial resistance are alarming worldwide. Therefore, this study aims to describe the prevalence and the resistance pattern of the main bacteria responsible for UTIS Escherichia coli (E. coli). Retrospective chart review for patients admitted to emergency department and diagnosed with UTIS at KAMC, in Riyadh, Saudi Arabia between January to March 2008 was performed. Antimicrobial susceptibility to ampicillin, augmentin (amoxicillin/clavulanate), cefazolin, co-trimoxazole (sulfamethoxazole/trimethoprim), ciprofloxacin, and nitrofurantoin, and cefpodoxime was determined for 101 E. coli urinary isolates. Escherichia coli was the most prevalent pathogen contributing to UTIS representing 93.55, 60.24, and 45.83% of all pathogen isolated from urine culture of pediatric, adult, and elderly, respectively. High rates of resistance to ampicillin (82.76, 58, and 63.64%) and co-trimoxazole (51.72, 42, and 59.09%), among E. coli isolated from pediatric, adult and elderly respectively. Nitrofurantoin was the most active agent, followed by ciprofloxacin, augmentin and cefazolin. 22.77% of E. coli isolates exhibited multiple drug resistance (MDR). Among 66 and 49 isolates resistant to ampicillin and co-trimoxazole, respectively, 34.84 and 42.85% were MDR. In contrast, all isolates resistant to augmentin and nitrofurantoin were MRD, while 72.7 and 82.4% of isolates resistant to ciprofloxacin and cefazolin were MDR. High resistance was observed to ampicillin and co-trimoxazole which commonly used as empirical treatments for UTIS, limiting their clinical use. This necessitates continuous surveillance for resistance pattern of uropathogens against antibiotics.

  17. MICROBIOLOGICAL ASPECTS OF ESCHERICHIA COLI IN URINARY TRACT INFECTIONS IN SOWS OF COMMERCIAL FARMS IN SINOP-MT

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    L. F. B. Venancio

    2017-12-01

    Full Text Available Urinary infections (UI in nuts are highly prevalent in modern intensive farming systems and cause significant economic losses, especially for reproductive failure and shortening the life of the array. The most frequently isolated agent is the bacterium Escherichia coli (E. coli. Variables such as environmental contamination pressure, management, nutrition, physiological and anatomical facilities and conditions of the animal itself are directly linked to illness. The objective of this work was to monitor microbiological urine nuts with suspected UI on commercial farms in the municipality of Sinop-MT, by counting of aerobic mesophilic total of Escherichia coli research and antimicrobial susceptibility profile. Urine samples with aerobic mesophilic total counts above 105UFC / mL were considered positive, confirming IU in 12 samples (28.57% of the 42 females subjected to collections. Of the 42 urine samples, 305 were isolated colonies of Gram negative bacteria and through biochemical tests it was confirmed E.coli in 165 (54.09% of these. In 37 (88.09% of the 42 samples collected had involvement of E. coli, with or without other pathogens and all positive samples for UI by total aerobic mesophilic bacteria count showed. Through the antimicrobial susceptibility profile test, E. coli strains showed sensitivity to the following percentages: Gentamicin (100%, Streptomycin (98.70%, Neomycin (92.85% Doxycycline (91.55% , Enrofloxacin (80.51%, Sulfazotrim (64.28%, Ampicillin (62.97%, tetracycline (61.68% and Amoxicillin (24.04%. The diagnosis of UI should be carried out thoroughly, assessing clinical and microbiological aspects, for the identification of the microorganism involved and the realization of antimicrobial susceptibility testing prevents the appearance of multi-resistant bacterial strains.

  18. Regional variations in fluoroquinolone non-susceptibility among Escherichia coli bloodstream infections within the Veterans Healthcare Administration

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    Daniel J. Livorsi

    2016-10-01

    Full Text Available Abstract Objectives We sought to define regional variations in fluoroquinolone non-susceptibility (FQ-NS among bloodstream isolates of Escherichia coli across the Veterans Health Administration (VHA in the United States. Methods We analyzed a retrospective cohort of patients managed at 136 VHA hospitals who had a blood culture positive for E.coli between 2003 and 2013. Hospitals were classified based on US Census Divisions, and regional variations in FQ-NS were analyzed. Results Twenty-four thousand five hundred twenty-three unique E.coli bloodstream infections (BSIs were identified between 2003 and 2013. 53.9 % of these were community-acquired, 30.7 % were healthcare-associated, and 15.4 % were hospital-onset BSIs. The proportion of E.coli BSIs with FQ-NS significantly varied across US Census Divisions (p < 0.001. During 2003–2013, the proportion of E.coli BSIs with FQ-NS was highest in the West South-Central Division (32.7 % and lowest in the Mountain Division (20.0 %. Multivariable analysis showed that there were universal secular trends towards higher FQ-NS rates (p < 0.001 with significant variability of slopes across US Census Divisions (p < 0.001. Conclusion There has been a universal increase in FQ-NS among E.coli BSIs within VHA, but the rate of increase has significantly varied across Census Divisions. The reasons for this variability are unclear. These findings reinforce the importance of using local data to develop and update local antibiograms and antibiotic-prescribing guidelines.

  19. Changes in thermal nociceptive responses in dairy cows following experimentally induced Escherichia coli mastitis

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    Klaas Ilka C

    2011-05-01

    Full Text Available Abstract Background Mastitis is a high incidence disease in dairy cows. The acute stage is considered painful and inflammation can lead to hyperalgesia and thereby contribute to decreased welfare. The aim of this study was to examine changes in nociceptive responses toward cutaneous nociceptive laser stimulation (NLS in dairy cows with experimentally induced Escherichia coli mastitis, and correlate behavioral changes in nociceptive responses to clinical and paraclinical variables. Methods Seven Danish Holstein-Friesian cows were kept in tie-stalls, where the E. coli associated mastitis was induced and laser stimulations were conducted. Measurements of rectal temperature, somatic cell counts, white blood cell counts and E. coli counts were conducted. Furthermore, scores were given for anorexia, local udder inflammation and milk appearance to quantify the local and systemic disease response. In order to quantify the nociceptive threshold, behavioral responses toward cutaneous NLS applied to six skin areas at the tarsus/metatarsus and udder hind quarters were registered at evening milking on day 0 (control and days 1, 2, 3, 6 and 10 after experimental induction of mastitis. Results All clinical and paraclinical variables were affected by the induced mastitis. All cows were clinically ill on days 1 and 2. The cows responded behaviorally toward the NLS. For hind leg stimulation, the proportion of cows responding by stepping was higher on day 0 than days 3 and 6, and the frequency of leg movements after laser stimulation tended to decrease on day 1 compared to the other days. After udder stimulation, the proportion of cows responding by stepping was higher on day 1 than on all other days of testing. Significant correlations between the clinical and paraclinical variables of disease and the behavioral responses toward nociceptive stimulation were found. Conclusions Changes in behavioral responses coincide with peaks in local and systemic signs of E

  20. Intranasal immunization with fusion protein MrpH·FimH and MPL adjuvant confers protection against urinary tract infections caused by uropathogenic Escherichia coli and Proteus mirabilis.

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    Habibi, Mehri; Asadi Karam, Mohammad Reza; Shokrgozar, Mohammad Ali; Oloomi, Mana; Jafari, Anis; Bouzari, Saeid

    2015-04-01

    Urinary tract infections (UTIs) caused by Uropathogenic Escherichia coli (UPEC) and Proteus mirabilis are among the most common infections in the world. Currently there are no vaccines available to confer protection against UTI in humans. In this study, the immune responses and protection of FimH of UPEC with MrpH antigen of P. mirabilis in different vaccine formulations with and without MPL adjuvant were assessed. Mice intranasally immunized with the novel fusion protein MrpH·FimH induced a significant increase in IgG and IgA in serum, nasal wash, vaginal wash, and urine samples. Mice immunized with fusion MrpH·FimH also showed a significant boost in cellular immunity. Addition of MPL as the adjuvant enhanced FimH and MrpH specific humoral and cellular responses in both systemic and mucosal samples. Vaccination with MrpH·FimH alone or in combination with MPL showed the highest efficiency in clearing bladder and kidney infections in mice challenged with UPEC and P. mirabilis. These findings may indicate that the protection observed correlates with the systemic, mucosal and cellular immune responses induced by vaccination with these preparations. Our data suggest MrpH·FimH fusion protein with or without MPL as adjuvant could be potential vaccine candidates for elimination of UPEC and P. mirabilis. These data altogether are promising and these formulations are good candidates for elimination of UPEC and P. mirabilis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Expression of bacterial virulence factors and cytokines during in vitro macrophage infection by enteroinvasive Escherichia coli and Shigella flexneri: a comparative study

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    Silvia Y Bando

    2010-09-01

    Full Text Available Enteroinvasive Escherichia coli (EIEC and Shigellaspp cause bacillary dysentery in humans by invading and multiplying within epithelial cells of the colonic mucosa. Although EIEC and Shigellashare many genetic and biochemical similarities, the illness caused by Shigellais more severe. Thus, genomic and structure-function molecular studies on the biological interactions of these invasive enterobacteria with eukaryotic cells have focused on Shigella rather than EIEC. Here we comparatively studied the interactions of EIEC and of Shigella flexneriwith cultured J774 macrophage-like cells. We evaluated several phenotypes: (i bacterial escape from macrophages after phagocytosis, (ii macrophage death induced by EIEC and S. flexneri, (iii macrophage cytokine expression in response to infection and (iv expression of plasmidial (pINV virulence genes. The results showed thatS. flexneri caused macrophage killing earlier and more intensely than EIEC. Both pathogens induced significant macrophage production of TNF, IL-1 and IL-10 after 7 h of infection. Transcription levels of the gene invasion plasmid antigen-C were lower in EIEC than in S. flexneri throughout the course of the infection; this could explain the diminished virulence of EIEC compared to S. flexneri.

  2. Quiescent complement in nonhuman primates during E coli Shiga toxin-induced hemolytic uremic syndrome and thrombotic microangiopathy.

    Science.gov (United States)

    Lee, Benjamin C; Mayer, Chad L; Leibowitz, Caitlin S; Stearns-Kurosawa, D J; Kurosawa, Shinichiro

    2013-08-01

    Enterohemorrhagic Escherichia coli (EHEC) produce ribosome-inactivating Shiga toxins (Stx1, Stx2) responsible for development of hemolytic uremic syndrome (HUS) and acute kidney injury (AKI). Some patients show complement activation during EHEC infection, raising the possibility of therapeutic targeting of complement for relief. Our juvenile nonhuman primate (Papio baboons) models of endotoxin-free Stx challenge exhibit full spectrum HUS, including thrombocytopenia, hemolytic anemia, and AKI with glomerular thrombotic microangiopathy. There were no significant increases in soluble terminal complement complex (C5b-9) levels after challenge with lethal Stx1 (n = 6) or Stx2 (n = 5) in plasma samples from T0 to euthanasia at 49.5 to 128 hours post-challenge. d-dimer and cell injury markers (HMGB1, histones) confirmed coagulopathy and cell injury. Thus, complement activation is not required for the development of thrombotic microangiopathy and HUS induced by EHEC Shiga toxins in these preclinical models, and benefits or risks of complement inhibition should be studied further for this infection.

  3. Trimethoprim in vitro antibacterial activity is not increased by adding sulfamethoxazole for pediatric Escherichia coli urinary tract infection.

    Science.gov (United States)

    Nguyen, Hiep T; Hurwitz, Richard S; Defoor, W Robert; Minevich, Eugene; McAdam, Alexander J; Mortensen, Joel E; Novak-Weekley, Susan M; Minnillo, Brian J; Elder, Jack S

    2010-07-01

    The combination of trimethoprim/sulfamethoxazole is often used to treat uncomplicated urinary tract infections in children. The rationale for combining trimethoprim and sulfamethoxazole is that they may act synergistically to increase antibacterial activity. However, approximately 3% of patients show allergic reactions to sulfamethoxazole, of which some are serious (liver failure and Stevens-Johnson syndrome). We determined whether adding sulfamethoxazole is necessary to increase in vitro antibacterial activity for pediatric urinary tract infection compared to that of trimethoprim alone. We prospectively identified 1,298 children with urinary tract infection (greater than 100,000 cfu/ml Escherichia coli) from a total of 4 American regions. In vitro susceptibility of bacterial isolates to sulfamethoxazole, trimethoprim and trimethoprim/sulfamethoxazole was determined using disk diffusion. Ampicillin susceptibility was tested at 2 sites. At 1 site all uropathogens from consecutive urinary isolates were evaluated. E. coli susceptibility to trimethoprim was 70%, comparable to the 70% of trimethoprim/sulfamethoxazole (p = 0.9) and higher than the 56.9% of sulfamethoxazole (p trimethoprim was significantly higher than to ampicillin. At 1 site the susceptibility of other uropathogens to trimethoprim and trimethoprim/sulfamethoxazole was similar to that of E. coli. In children with urinary tract infection in vitro susceptibility to trimethoprim was comparable to that to trimethoprim/sulfamethoxazole and significantly higher than to sulfamethoxazole. This finding was similar at all sites. Adding sulfamethoxazole appears unnecessary and may represent a risk to patients. Trimethoprim can be used as an alternative to trimethoprim/sulfamethoxazole based on in vitro antibacterial susceptibility. Routine trimethoprim/sulfamethoxazole use for urinary tract infection should be carefully reevaluated. Copyright (c) 2010 American Urological Association Education and Research, Inc

  4. Cross-modulation of pathogen-specific pathways enhances malnutrition during enteric co-infection with Giardia lamblia and enteroaggregative Escherichia coli.

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    Bartelt, Luther A; Bolick, David T; Mayneris-Perxachs, Jordi; Kolling, Glynis L; Medlock, Gregory L; Zaenker, Edna I; Donowitz, Jeffery; Thomas-Beckett, Rose Viguna; Rogala, Allison; Carroll, Ian M; Singer, Steven M; Papin, Jason; Swann, Jonathan R; Guerrant, Richard L

    2017-07-01

    Diverse enteropathogen exposures associate with childhood malnutrition. To elucidate mechanistic pathways whereby enteric microbes interact during malnutrition, we used protein deficiency in mice to develop a new model of co-enteropathogen enteropathy. Focusing on common enteropathogens in malnourished children, Giardia lamblia and enteroaggregative Escherichia coli (EAEC), we provide new insights into intersecting pathogen-specific mechanisms that enhance malnutrition. We show for the first time that during protein malnutrition, the intestinal microbiota permits persistent Giardia colonization and simultaneously contributes to growth impairment. Despite signals of intestinal injury, such as IL1α, Giardia-infected mice lack pro-inflammatory intestinal responses, similar to endemic pediatric Giardia infections. Rather, Giardia perturbs microbial host co-metabolites of proteolysis during growth impairment, whereas host nicotinamide utilization adaptations that correspond with growth recovery increase. EAEC promotes intestinal inflammation and markers of myeloid cell activation. During co-infection, intestinal inflammatory signaling and cellular recruitment responses to EAEC are preserved together with a Giardia-mediated diminishment in myeloid cell activation. Conversely, EAEC extinguishes markers of host energy expenditure regulatory responses to Giardia, as host metabolic adaptations appear exhausted. Integrating immunologic and metabolic profiles during co-pathogen infection and malnutrition, we develop a working mechanistic model of how cumulative diet-induced and pathogen-triggered microbial perturbations result in an increasingly wasted host.

  5. Prevalence of antimicrobial resistant Escherichia coli from patients with suspected urinary tract infection in primary care, Denmark.

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    Córdoba, Gloria; Holm, Anne; Hansen, Frank; Hammerum, Anette M; Bjerrum, Lars

    2017-10-10

    Escherichia coli is the most common pathogen causing Urinary Tract Infections (UTI). Data from the current National Surveillance program in Denmark (DANMAP) may not accurately represent the prevalence of resistant E. coli in primary care, because only urine samples from complicated cases may be forwarded to the microbiological departments at hospitals for diagnostic examination. The aim of this study was to assess the prevalence of resistant E. coli to the most commonly used antimicrobial agents in primary care in a consecutive sample of patients from general practice. Observational study carried out from December 2014 to December 2015. Thirty-nine general practices from The Capital Region of Denmark included adult patients with urinary tract symptoms and suspected UTI. All urine samples were sent to the central laboratory Statens Serum Institut (SSI). Significant bacteriuria was interpreted according to the European Urinalysis Standards. Susceptibility testing was performed and interpreted according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) standards. From the 39 general practices 505 patients were recruited. Completed data were obtained from 485 (96%) patients. According to the European Urinalysis Standards, 261 (54%) patients had positive bacteriuria. The most common uropathogen in patients with uncomplicated (uUTI) and complicated (cUTI) urinary tract infection was E. coli 105 (69%) and 76 (70%), respectively. Eighty-two (45%) of 181 E. coli isolates were resistant to at least one of the tested antibiotics and 50 out of 82 isolates were resistant to two or more antimicrobial agents. The highest resistance-rate was found against ampicillin 34% (95% CI 24;42) in uUTI and 36% (24;46) in cUTI. There were no differences in the distribution of resistance between uncomplicated and complicated cases. The prevalence of resistance was similar to the one reported in DANMAP 2014. In E. coli from uUTI there is high resistance rates to

  6. The prevalence of O serogroups of Escherichia coli strains causing acute urinary tract infection in children in Iran

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    Fatemeh Emamghorashi

    2011-01-01

    Full Text Available The aim of present study was to determine the prevalence of O serogroups of Escherichia coli (E. coli strains that cause community-acquired urinary tract infections (UTI in children. In this study, 96 children with UTI referred to two Jahrom University-affiliated Hospitals in Iran were enrolled, during the period from August 2005 to August 2006. Drug sensitivity was tested by disk diffusion method and serotyping done by slide agglutination method. A total of 96 E. coli strains were isolated from urine samples of the study children whose age ranged from one month to 14 years. Cystitis was diagnosed in 49.2% and pyelonephritis in 50.8% of the study patients. Maximum drug resistance was seen with ampicilin (80.2% and the least with imipenem (1.1%. The most common type of O antigen was O1 (12.2%. There was significant correlation between the presence of O antigens and sensitivity to nalidixic acid and gentamicin (P < 0.05. This is the first report of E. coli serotyping in children with UTI from the south of Iran and their relation to antibiotic resistance and clinical presentation. Further studies from other parts of Iran and on other serotypes are recommended.

  7. O-serotyping of Escherichia coli Strains isolated from Patients With Urinary Tract Infection in Southeast of Iran

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    Ahmad Rashki

    2014-11-01

    Full Text Available Background: Uropathogenic Escherichia coli (UPEC O-serogroups with their phylogenetic background are the most prevalent causes of urinary tract infections (UTIs. Objectives: The association of O types with phylogenetic background was assessed among E. coli isolates collected from patients with UTI. Patients and Methods: In this study, 186 patients with UTI, referred to two hospitals affiliated to Zabol University of Medical Sciences in southeast of Iran, were enrolled during January to July 2013. Phylogenetic groups and serotyping were performed using multiplex-PCR method. Results: A total of 100 E. coli strains were isolated from the urine samples. The most common types of O antigens were O2 (16.43%, O6 (16.43% and O18 (13.69%. The phylogenetic analysis showed that 63 O-antigen-positive isolates were mainly segregated from the phylogenetic group B2 (56% and the substantial prevalence (30% belonged to the phylogenetic group D. Conclusions: This was the first report of E. coli serotyping in patient with UTI from southeast of Iran as well as investigation of their relation with phylogenetic pattern by multiplex-PCR. Further studies from other parts of Iran and on other serotypes are recommended.

  8. Abortive phage-infection and UV-protection markers on ColI plasmids from epidemic strains of Salmonella

    International Nuclear Information System (INIS)

    Barker, R.M.

    1988-01-01

    Cultures of Escherichia coli carrying ColI plasmids received in conjugation from strains of Salmonella typhimurium and S. agona were examined for abortive infection (Abi) of phage BF23 and for enhanced resistance to the lethal action of UV-irradiation (Uvr). The Abi character of stored cultures of E. coli was also compared with the reaction of the same stock culture tested 5 years before. Seven of the eight potential types differentiated by three characters were represented among 160 ColI plasmids: ColIa Abi + Uvr + (3 plasmids), ColIa Abi - Uvr + (1), ColIa Abi - Uvr-> (2), ColIb Abi + Uvr + (85), ColIb Abi + Uvr - (5), ColIb Abi - Uvr + (4), ColIb Abi-? Uvr - (60). Recognition that different plasmid types could be carried by strains of a clone proved useful in the interpretation of the epidemic spread of strains of S. typhimurium of phage type/biotype 141/9f in Scotland and in tracing the ancestry of a recently emerged rhamnose non-fermenting mutant strain of S. agona. (author)

  9. [Evaluation of antibiotic resistance of Escherichia coli in urinary tract infections in Primary Care Barbastro Sector (Huesca)].

    Science.gov (United States)

    Betrán, Ana; Cortés, Ana Ma; López, Concepción

    2015-10-01

    Evaluate the resistance of community-uropathogen, Escherichia coli to several antibiotics in our health sector and deduce empirical treatment options. E. coli strains isolated from urine cultures of patients from Primary Care Barbastro Sector, between January 2011 and December 2013, were studied. The resistances rates for nine common antibiotics were determined, and differences in sensitivity were analyzed, comparing confidence intervals for proportions by the method of Wilson. E. coli was the most frequently isolated bacteria (61.08% of positive urine cultures sent from Primary Care). Overall, there has been an increase in resistance of E. coli isolates in all antimicrobials studied. Still, resistance has remained below 4% compared to fosfomycin and nitrofurantoin and below 10% in cephalosporins second and third generation. Resistance to amoxicillin-clavulanate has increased progressively reaching 21.5% in 2013; only this antibiotic has presented a statistically significant increase. The maximum levels of resistance (over 30%) were found in the antibiotics administered orally and often indicated in uncomplicated urinary tract infections: trimethoprim-sulfamethoxazole, ciprofloxacin and ampicillin. Update knowledge susceptibility patterns of microorganisms most commonly isolated in urine samples in each health area allows to choose the most suitable and effective treatments trough empirical knowledge.

  10. Mechanism of growth delay induced in Escherichia coli by near ultraviolet radiation

    International Nuclear Information System (INIS)

    Ramabhadran, T.V.; Jagger, J.

    1976-01-01

    Continuously growing cultures of E. coli B/r were irradiated with a fluence of broad-band near-ultraviolet radiation (315 to 405 nm) sufficient to cause extensive growth delay and complete cessation of net RNA synthesis. Chloramphenicol treatment was found to stimulate resumption of RNA synthesis, similar to that observed with chloramphenicol treatment after amino-acid starvation. E. coli strains in which amino-acid starvation does not result in cessation of RNA synthesis (''relaxed'' or rel - strains) show no cessation of growth and only a slight effect on the rate of growth or of RNA synthesis. These findings show that such near-uv fluences do not inactivate the RNA synthetic machinery but affect the regulation of RNA synthesis, in a manner similar to that produced by amino-acid starvation. Such regulation is believed to be mediated through alterations in concentration of guanosine tetraphosphate (ppGpp), and our estimations of ppGpp after near-uv irradiation are consistent with such an interpretation. These data, combined with earlier published data, strongly suggest that the mechanism of near-uv-induced growth delay in E. coli involves partial inactivation of certain tRNA species, which is interpreted by the cell in a manner similar to that of amino-acid starvation, causing a rise in ppGpp levels, a shut-off of net RNA synthesis, and the induction of a growth delay

  11. Escherichia coli O157:H7: Animal Reservoir and Sources of Human Infection

    Science.gov (United States)

    Ferens, Witold A.

    2011-01-01

    Abstract This review surveys the literature on carriage and transmission of enterohemorrhagic Escherichia coli (EHEC) O157:H7 in the context of virulence factors and sampling/culture technique. EHEC of the O157:H7 serotype are worldwide zoonotic pathogens responsible for the majority of severe cases of human EHEC disease. EHEC O157:H7 strains are carried primarily by healthy cattle and other ruminants, but most of the bovine strains are not transmitted to people, and do not exhibit virulence factors associated with human disease. Prevalence of EHEC O157:H7 is probably underestimated. Carriage of EHEC O157:H7 by individual animals is typically short-lived, but pen and farm prevalence of specific isolates may extend for months or years and some carriers, designated as supershedders, may harbor high intestinal numbers of the pathogen for extended periods. The prevalence of EHEC O157:H7 in cattle peaks in the summer and is higher in postweaned calves and heifers than in younger and older animals. Virulent strains of EHEC O157:H7 are rarely harbored by pigs or chickens, but are found in turkeys. The bacteria rarely occur in wildlife with the exception of deer and are only sporadically carried by domestic animals and synanthropic rodents and birds. EHEC O157:H7 occur in amphibian, fish, and invertebrate carriers, and can colonize plant surfaces and tissues via attachment mechanisms different from those mediating intestinal attachment. Strains of EHEC O157:H7 exhibit high genetic variability but typically a small number of genetic types predominate in groups of cattle and a farm environment. Transmission to people occurs primarily via ingestion of inadequately processed contaminated food or water and less frequently through contact with manure, animals, or infected people. PMID:21117940

  12. Phleomycin-induced lethality and DNA degradation in Escherichia coli K12

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, H

    1975-01-01

    The cell lethality and DNA fragmentation caused by phleomycin (PM) were studied in E. coli K12 strains with special reference to the effects of repair or recombination deficiencies and metabolic inhibitors. Unlike excision-defective derivatives of E. coli B, uvrA, uvrB, and uvrC mutants of strain K12 showed no peculiarities compared with wild type in regard to cell survival. Likewise, mutant alleles at uvrD and polA loci had no effect. In contrast, rec mutants were more sensitive to PM-killing than were rec/sup +/ strains. PM-induced strand breakage in DNA was observed in all strains tested including the above-mentioned mutants. There was no significant distinction between the uvr mutants and the wild type strain, indicating that the uvr-endonuclease was not responsible for the strand breaks. Involvement of endonuclease I was also ruled out. At least some of the PM-induced strand breaks were repairable. PM-induced lethality and strand breakage were totally dependent on energy supply. Inhibition of protein synthesis resulted in a partial and parallel suppression of the two effects. Our results suggest that the lethality is due to DNA strand breakage and the repair of such damage is postulated to be controlled by rec genes.

  13. Modeling of kinetics of the inducible protein complexes of the SOS system in bacteria E. coli which realize TLS process

    International Nuclear Information System (INIS)

    Belov, O.V.

    2008-01-01

    The mathematical model describing kinetics of the inducible genes of the protein complexes, formed during SOS response in bacteria Escherichia coli is developed. Within the bounds of developed approaches the auxiliary mathematical model describing changes in concentrations of the dimers, which are the components of final protein complexes, is developed. The solutions of both models are based on the experimental data concerning expression of the basic genes of the SOS system in bacteria Escherichia coli

  14. Mechanism of SOS-induced targeted and untargeted mutagenesis in E. coli

    International Nuclear Information System (INIS)

    Maenhaut-Michel, G.

    1985-01-01

    This paper retraces the evolution of hypotheses concerning mechanisms of SOS induced mutagenesis. Moreover, it reports some recent data which support a new model for the mechanism of targeted and untargeted mutagenesis in E. coli. In summary, the SOS mutator effect, which is responsible for untargeted mutagenesis and perhaps for the misincorporation step in targeted mutagenesis, is believed to involve a fidelity function associated with DNA polymerase III and does not require the umuC gene product. umuC and umuD gene products are probably required specifically for elongation of DNA synthesis past blocking lesions, i.e. to allow mutagenic replication of damaged DNA

  15. Biologically Synthesized Gold Nanoparticles Ameliorate Cold and Heat Stress-Induced Oxidative Stress in Escherichia coli

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    Xi-Feng Zhang

    2016-06-01

    Full Text Available Due to their unique physical, chemical, and optical properties, gold nanoparticles (AuNPs have recently attracted much interest in the field of nanomedicine, especially in the areas of cancer diagnosis and photothermal therapy. Because of the enormous potential of these nanoparticles, various physical, chemical, and biological methods have been adopted for their synthesis. Synthetic antioxidants are dangerous to human health. Thus, the search for effective, nontoxic natural compounds with effective antioxidative properties is essential. Although AuNPs have been studied for use in various biological applications, exploration of AuNPs as antioxidants capable of inhibiting oxidative stress induced by heat and cold stress is still warranted. Therefore, one goal of our study was to produce biocompatible AuNPs using biological methods that are simple, nontoxic, biocompatible, and environmentally friendly. Next, we aimed to assess the antioxidative effect of AuNPs against oxidative stress induced by cold and heat in Escherichia coli, which is a suitable model for stress responses involving AuNPs. The response of aerobically grown E. coli cells to cold and heat stress was found to be similar to the oxidative stress response. Upon exposure to cold and heat stress, the viability and metabolic activity of E. coli was significantly reduced compared to the control. In addition, levels of reactive oxygen species (ROS and malondialdehyde (MDA and leakage of proteins and sugars were significantly elevated, and the levels of lactate dehydrogenase activity (LDH and adenosine triphosphate (ATP significantly lowered compared to in the control. Concomitantly, AuNPs ameliorated cold and heat-induced oxidative stress responses by increasing the expression of antioxidants, including glutathione (GSH, glutathione S-transferase (GST, super oxide dismutase (SOD, and catalase (CAT. These consistent physiology and biochemical data suggest that AuNPs can ameliorate cold and

  16. Radiation-induced tetramer-to-dimer transition of Escherichia coli lactose repressor

    International Nuclear Information System (INIS)

    Goffinont, S.; Davidkova, M.; Spotheim-Maurizot, M.

    2009-01-01

    The wild type lactose repressor of Escherichia coli is a tetrameric protein formed by two identical dimers. They are associated via a C-terminal 4-helix bundle (called tetramerization domain) whose stability is ensured by the interaction of leucine zipper motifs. Upon in vitro γ-irradiation the repressor losses its ability to bind the operator DNA sequence due to damage of its DNA-binding domains. Using an engineered dimeric repressor for comparison, we show here that irradiation induces also the change of repressor oligomerisation state from tetramer to dimer. The splitting of the tetramer into dimers can result from the oxidation of the leucine residues of the tetramerization domain.

  17. Efek ekstrak daun singkong (Manihot utilissima terhadap ekspresi COX-2 pada monosit yang dipapar LPS E.coli (The effect of Manihot utilissima extracts on COX-2 expression of monocytes induced by LPS E. coli

    Directory of Open Access Journals (Sweden)

    Zahara Meilawaty

    2013-12-01

    Full Text Available Background: Periodontal disease is a common and widespread disease in the community. Gram negative bacteria have a role inperiodontitis. These bacteria secrete a variety of products such as endotoxin lipopolysaccharide (LPS, which causes the occurrenceof inflammation or infection. The body defense responses are neutrophils and mononuclear cells (monocytes and macrophages. Inresponse to defense mechanism, the body will be expressed enzyme cyclooxygenase (COX which functions convert arachidonic acidto prostaglandins. Cassava leaf cells known to play a role in reducing inflammation, but the mechanism for inhibiting COX-2, is notknown. Purpose: The study was aimed to determine the effect of cassava leaf extract (Manihot utilissima on expression of enzyme COX-2 in monocytes which were exposed by LPS E. coli. Methods: This study was in vitro experimental studies with the design of posttestonly control group design. The sample was the cassava leaves extract (Manihot utilissima at concentration of 12.5 % and 25 %. Theexpression of COX-2 was determined by immunocytochemistry method. Isolated monocytes were incubated in cassava leaf extract, andthen exposed to LPS, after washing imunostaning procedure was performed using a monoclonal antibody (MAb anti-human COX-2.The research data was the number of monocytes that express COX-2. Results: Expression of COX-2 in the group cassava leaf extractwas higher than the group that induced by LPS E. coli only. Conclusion: Cassava leaf extract did not inhibit the expression of COX-2in monocytes which were exposed by LPS E. coli.Latar belakang: Penyakit periodontal merupakan penyakit umum dan tersebar luas di masyarakat. Bakteri yang banyak berperanpada periodontitis adalah Gram negatif. Bakteri ini mengeluarkan berbagai produk antara lain endotoksin lipopolisakarida (LPS yangmenyebabkan inflamasi atau infeksi. Respon pertahanan tubuh pertama adalah netrofil dan sel mononuklear (monosit dan makrofag.Pada respon

  18. YnfA , a SMR family efflux pump is abundant in Escherichia coli isolates from urinary infection

    Directory of Open Access Journals (Sweden)

    S K Sarkar

    2015-01-01

    Full Text Available A quantitative study was undertaken to determine the expression level of different efflux pumps in multi-drug-resistant (MDR Escherichia coli isolates from urinary infection. We have determined the presence of different efflux pumps and measured the expression level of tolC, mdfA, norE and ynfA genes among 48 isolates by quantitative real-time PCR. The expression level of tolC and ynfA was constantly high and observed among 75-80% of isolates, whereas mdfA and norE were expressed occasionally. Our findings suggest that ynfA, a new SMR efflux pump gene family member increases the antibiotics′ resistance in E. coli.

  19. Protection against an infectious disease by enterohaemorrhagic E. coli 0-157.

    Science.gov (United States)

    Ota, A

    1999-07-01

    Preventive measures against infection by enterohaemorrhagic E. coli 0-157 are described. Eating yoghurt and Kefir supposedly induces more bifid bacteria and lactic acid bacteria to colonize in the intestines, thereby protecting humans from infection by E. coli 0-157. Some foods, such as plum extract, act as a mild antibiotic and produce an acidic environment within the intestine, thus interfering with growth of the E. coli 0-157. The natural colonization of harmless E. coli or other bacteria that are more powerful than E. coli 0-157 can possibly protect against infection. A vaccination against E. coli 0-157 H7 may also be effective. In addition, it has been suggested that the correct levels of nitric oxide and calcium in the blood may activate immunity and protect against infection by E. coli 0-157.

  20. Gut Microbiota-Induced Immunoglobulin G Controls Systemic Infection by Symbiotic Bacteria and Pathogens

    Science.gov (United States)

    Zeng, Melody Y.; Cisalpino, Daniel; Varadarajan, Saranyaraajan; Hellman, Judith; Warren, H. Shaw; Cascalho, Marilia; Inohara, Naohiro; Núñez, Gabriel

    2016-01-01

    The gut microbiota is compartmentalized in the intestinal lumen and induces local immune responses, but it remains unknown whether the gut microbiota can induce systemic response and contribute to systemic immunity. We report that selective gut symbiotic gram-negative bacteria were able to disseminate systemically to induce immunoglobulin G (IgG) response, which primarily targeted gram-negative bacterial antigens and conferred protection against systemic infections by E. coli and Salmonella by directly coating bacteria to promote killing by phagocytes. T cells and Toll-like receptor 4 on B cells were important in the generation of microbiota-specific IgG. We identified murein lipoprotein (MLP), a highly conserved gram-negative outer membrane protein, as a major antigen that induced systemic IgG homeostatically in both mice and humans. Administration of anti-MLP IgG conferred crucial protection against systemic Salmonella infection. Thus, our findings reveal an important function for the gut microbiota in combating systemic infection through the induction of protective IgG. PMID:26944199

  1. The incidence and risk factors of resistant E. coli infections after prostate biopsy under fluoroquinolone prophylaxis: a single-centre experience with 2215 patients.

    Science.gov (United States)

    Kandemir, Özlem; Bozlu, Murat; Efesoy, Ozan; Güntekin, Onur; Tek, Mesut; Akbay, Erdem

    2016-08-01

    We evaluated the incidence and risk factors of resistant Escherichia coli infections after the prostate biopsy under flouroquinolone prophylaxis. From January 2003 to December 2012, we retrospectively evaluated the records of 2215 patients. The risk factors were described for infective complications and resistant E. coli in positive cultures was calculated. Of 2215 patients, 153 had positive urine cultures, such as 129 (84·3%) E. coli, 8 (5·2%) Enterococcus spp., 6 (3·9%) Enterobacter spp., 5 (3·2%) Pseudomonas spp., 3 (1·9%) MRCNS, and 2 (1·3%) Klebsiella spp. Of the positive urine cultures which yielded E. coli, 99 (76·7%) were evaluated for fluoroquinolone resistance. Of those, 83 (83·8%) were fluoroquinolone-resistant and composed of 51 (61·4%) extended-spectrum beta-lactamase (ESBL)-positive. Fluoroquinolone-resistant E. coli ratios were 73·4 and 95·9% before 2008 and after 2008, respectively (P = 0·002). The most sensitive antibiotics for fluoroquinolone-resistant E. coli strains were imipenem (100%), amikacin (84%) and cefoperazone (83%). The use of quinolones in the last 6 months and a history of hospitalization in the last 30 days were found to be significant risk factors. We found that resistant E. coli strains might be a common microorganism in patients with this kind of complication. The risk factors for development of infection with these resistant strains were history of the use of fluoroquinolones and hospitalization.

  2. Timeliness of Surveillance during Outbreak of Shiga Toxin–producing Escherichia coli Infection, Germany, 2011

    OpenAIRE

    Altmann, Mathias; Wadl, Maria; Altmann, Doris; Benzler, Justus; Eckmanns, Tim; Krause, Gérard; Spode, Anke; an der Heiden, Matthias

    2011-01-01

    In the context of a large outbreak of Shiga toxin–producing Escherichia coli O104:H4 in Germany, we quantified the timeliness of the German surveillance system for hemolytic uremic syndrome and Shiga toxin–producing E. coli notifiable diseases during 2003–2011. Although reporting occurred faster than required by law, potential for improvement exists at all levels of the information chain.

  3. Timeliness of Surveillance during Outbreak of Shiga Toxin–producing Escherichia coli Infection, Germany, 2011

    Science.gov (United States)

    Wadl, Maria; Altmann, Doris; Benzler, Justus; Eckmanns, Tim; Krause, Gérard; Spode, Anke; an der Heiden, Matthias

    2011-01-01

    In the context of a large outbreak of Shiga toxin–producing Escherichia coli O104:H4 in Germany, we quantified the timeliness of the German surveillance system for hemolytic uremic syndrome and Shiga toxin–producing E. coli notifiable diseases during 2003–2011. Although reporting occurred faster than required by law, potential for improvement exists at all levels of the information chain. PMID:22000368

  4. Crystallization and preliminary X-ray analysis of the inducible lysine decarboxylase from Escherichia coli

    International Nuclear Information System (INIS)

    Alexopoulos, Eftichia; Kanjee, Usheer; Snider, Jamie; Houry, Walid A.; Pai, Emil F.

    2008-01-01

    The structure of the decameric inducible lysine decarboxylase from E. coli was determined by SIRAS using a hexatantalum dodecabromide (Ta 6 Br 12 2+ ) derivative. Model building and refinement are under way. The decameric inducible lysine decarboxylase (LdcI) from Escherichia coli has been crystallized in space groups C2 and C222 1 ; the Ta 6 Br 12 2+ cluster was used to derivatize the C2 crystals. The method of single isomorphous replacement with anomalous scattering (SIRAS) as implemented in SHELXD was used to solve the Ta 6 Br 12 2+ -derivatized structure to 5 Å resolution. Many of the Ta 6 Br 12 2+ -binding sites had twofold and fivefold noncrystallographic symmetry. Taking advantage of this feature, phase modification was performed in DM. The electron-density map of LdcI displays many features in agreement with the low-resolution negative-stain electron-density map [Snider et al. (2006 ▶), J. Biol. Chem.281, 1532–1546

  5. Phenomenology of an inducible mutagenic DNA repair pathway in Escherichia coli: SOS repair hypothesis

    International Nuclear Information System (INIS)

    Radman, M.

    1974-01-01

    A hypothesis is proposed according to which E. coli possesses an inducible DNA repair system. This hypothetical repair, which we call SOS repair, is manifested only following damage to DNA, and requires de novo protein synthesis. SOS repair in E. coli requires some known genetic elements: recA + , lex + and probably zab + . Mutagenesis by ultraviolet light is observed only under conditions of functional SOS repair: we therefore suspect that this is a mutation-prone repair. A number of phenomena and experiments is reviewed which at this point can best be interpreted in terms of an inducible mutagenic DNA repair system. Two recently discovered phenomena support the proposed hypothesis: existence of a mutant (tif) which, after a shift to elevated temperature, mimicks the effect of uv irradiation in regard to repair of phage lambda and uv mutagenesis, apparent activation of SOS repair by introduction into the recipient cell of damaged plasmid or Hfr DNA. Several specific predictions based on SOS repair hypothesis are presented in order to stimulate further experimental tests. (U.S.)

  6. The antimutagenic effect of monoterpenes against UV-irradiation-, 4NQO- and t-BOOH-induced mutagenesis in coli

    Directory of Open Access Journals (Sweden)

    Nikolić Biljana

    2011-01-01

    Full Text Available The aim of this work was to investigate the antimutagenic potential of monoterpenes from sage and basil in Escherichia coli. The mutagenic potential of monoterpenes was pre-screened with Salmonella/microsome reversion assay in strain TA100 and no mutagenic effect was detected. The antimutagenic potential against UV- 4NQO- and t-BOOH induced mutagenesis was evaluated in E. coli K12 and E. coli WP2 by reversion assays. The obtained results indicate that camphor and thujone reduce UV- and 4NQO-induced mutations; myrcene reduces t-BOOH-induced mutations, while eucalyptol and linalool reduce mutagenicity by all tested mutagens. Considering evolutionary conservation of DNA repair and antioxidative protection, the obtained results indicate that further antigenotoxicity studies should be undertaken in eukaryotes.

  7. Protective effects of lactoferrin chimera and bovine lactoferrin in a mouse model of enterohaemorrhagic Escherichia coli O157:H7 infection

    NARCIS (Netherlands)

    Flores-Villaseñor, H.; Canizalez-Román, A.; Velazquez-Roman, J.; Nazmi, K.; Bolscher, J.G.M.; Leon-Sicairos, N.

    2012-01-01

    Mice orally infected with enterohaemorrhagic Escherichia coli (EHEC) O157:H7 were used to evaluate the activity of bovine lactoferrin (bLF) and the synthetic peptide LFchimera. Groups of BALB/c mice inoculated intragastrically with EHEC O157:H7 showed chronic intestinal infection with the pathogen

  8. Effect of Lactobacillus rhamnosus on the response of Galleria mellonella against Staphylococcus aureus and Escherichia coli infections.

    Science.gov (United States)

    Jorjão, Adeline Lacerda; de Oliveira, Felipe Eduardo; Leão, Mariella Vieira Pereira; Jorge, Antonio Olavo Cardoso; de Oliveira, Luciane Dias

    2018-04-01

    This study evaluated the prophylactic effects of the live or heat-killed probiotic strain Lactobacillus rhamnosus ATCC 7469 in Galleria mellonella, inoculated with Staphylococcus aureus or Escherichia coli. L. rhamnosus suspension was prepared and a part of it was autoclaved to obtain heat-killed lactobacilli. The larvae were inoculated of these suspensions and pathogenic. The survival of the larvae was observed during 7 days and after 24 h of inoculation haemocytes counted, melanization and nitric oxide production were analyzed. Larvae survival rate increased in the group inoculated with heat-killed L. rhamnosus, however, with no statistical difference. There was a significant increase in total haemocyte counts in all test groups. Haemolymph melanization and nitric oxide production were higher in the group inoculated with L. rhamnosus and infected with S. aureus. It was concluded that, in this model of infection, heat-killed L. rhamnosus ATCC 7469 promoted greater protection in Galleria mellonella infected with S. aureus or E. coli.

  9. Escherichia coli DinB inhibits replication fork progression without significantly inducing the SOS response.

    Science.gov (United States)

    Mori, Tetsuya; Nakamura, Tatsuro; Okazaki, Naoto; Furukohri, Asako; Maki, Hisaji; Akiyama, Masahiro Tatsumi

    2012-01-01

    The SOS response is readily triggered by replication fork stalling caused by DNA damage or a dysfunctional replicative apparatus in Escherichia coli cells. E. coli dinB encodes DinB DNA polymerase and its expression is upregulated during the SOS response. DinB catalyzes translesion DNA synthesis in place of a replicative DNA polymerase III that is stalled at a DNA lesion. We showed previously that DNA replication was suppressed without exogenous DNA damage in cells overproducing DinB. In this report, we confirm that this was due to a dose-dependent inhibition of ongoing replication forks by DinB. Interestingly, the DinB-overproducing cells did not significantly induce the SOS response even though DNA replication was perturbed. RecA protein is activated by forming a nucleoprotein filament with single-stranded DNA, which leads to the onset of the SOS response. In the DinB-overproducing cells, RecA was not activated to induce the SOS response. However, the SOS response was observed after heat-inducible activation in strain recA441 (encoding a temperature-sensitive RecA) and after replication blockage in strain dnaE486 (encoding a temperature-sensitive catalytic subunit of the replicative DNA polymerase III) at a non-permissive temperature when DinB was overproduced in these cells. Furthermore, since catalytically inactive DinB could avoid the SOS response to a DinB-promoted fork block, it is unlikely that overproduced DinB takes control of primer extension and thus limits single-stranded DNA. These observations suggest that DinB possesses a feature that suppresses DNA replication but does not abolish the cell's capacity to induce the SOS response. We conclude that DinB impedes replication fork progression in a way that does not activate RecA, in contrast to obstructive DNA lesions and dysfunctional replication machinery.

  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. Biodistribution of 99mTc-ketoconazole in infection initiated by candida albicans, staphylococcus aureus and escherichia coli

    International Nuclear Information System (INIS)

    Rizky Juwita Sugiharti; Iim Halimah; Isa Mahendra; Maula Eka Sriyani

    2016-01-01

    Infectious diseases remain a major health problem and cause of death worldwide, particularly in developing countries. Nuclear medicine imaging, with better sensitivity, offers an attractive option for diagnosis of infections. 99m Tc-ketoconazole was radiolabeled antibiotic which synthesized by labeling ketoconazole with radionuclide technetium-99m. This radiopharmaceutical is expected to be applied for detection of infection in nuclear medicine therefore 99m Tc-ketoconazole must be selectively concentrated in infection sites. Hence, evaluations of 99m Tc-ketoconazole to detect and locate infection caused by some microorganisms in mice have been conducted. The biodistribution study showed accumulation of 99m Tc ketoconazole in infected thigh at 1 hour p.i with target/non target ratio (T/NT) 3.04 for Candida albicans, 1.93 for Staphylococcus aureus and 2.81 for Escherichia coli. This study showed that 99m Tc-ketoconazole is a promising radiopharmaceutical to detect infection rapidly with high sensitivity. (author)

  12. Distinctive Gut Microbiota Is Associated with Diarrheagenic Escherichia coli Infections in Chilean Children

    Directory of Open Access Journals (Sweden)

    Pablo Gallardo

    2017-10-01

    Full Text Available Background: Diarrheagenic Escherichia coli (DEC strains are a major cause of diarrhea in children under 5 years of age worldwide. DEC pathogenicity relies on the interaction of bacteria with environmental factors, including the host's resident gut microbiota. Previous reports have shown changes in the gut microbiota's composition during episodes of diarrhea, which may increase the pathogenicity of DEC strains. More intense and detailed identification of microbiota strains specifically associated with DEC infections and disease is needed to pinpoint their role in DEC pathogenicity.Aim: To identify resident indicative bacterial taxa in DEC-positive diarrhea stool samples of Chilean children.Methods: We analyzed 63 diarrheal stool samples from children 1–5 years of age by FilmArray® GI in order to identify a potential pathogen and to group diarrhea episodes into those caused by DEC as sole pathogen (DEC group, 32 samples and those caused by an enteric virus as sole pathogen (viral group, 31 samples. In addition, 30 stool samples from healthy children, negative for enteric pathogens, were evaluated (healthy group. The 16S rRNA gene was amplified and sequenced using 454 pyrosequencing. Sequences were clustered into operational taxonomic units (OTUs at 99% identity and their representatives were used to assign them to operational phylogenetic units (OPUs using a phylogenetic inference approach.Results: Taxa assignment using the OPU approach resulted in a lower number of units but with higher accuracy compared to the OTU approach. Data analysis indicated an increase in sequences belonging to the phylum Proteobacteria in the DEC group compared to the viral and healthy groups. Samples displayed a statistically different community structure by sample grouping by redundancy analysis and ANOVA. Escherichia albertii (p = 0.001, Citrobacter werkmanii (p = 0.001, Yersinia enterocolitica, subsp. paleartica (p = 0.048, and Haemophilus sputorum (p = 0.028 were

  13. Pulsed-field gel electrophoresis typing of Escherichia coli strains from samples collected before and after pivmecillinam or placebo treatment of uncomplicated community-acquired urinary tract infection in women

    DEFF Research Database (Denmark)

    Ejrnaes, Karen; Sandvang, Dorthe; Lundgren, Bettina

    2006-01-01

    ). The finding that the majority of UTIs at follow-up are caused by the primary infecting E. coli strain supports the theory of a vaginal and rectal reservoir but could also support the recent discovery that E. coli strains are able to persist in the bladder epithelium despite appropriate antibiotic treatment......The primary infecting Escherichia coli strains from 156 women with community-acquired uncomplicated urinary tract infection (UTI) randomized to pivmecillinam or placebo and the E. coli strains causing UTI at two follow-up visits were typed using pulsed-field gel electrophoresis (PFGE......). In the pivmecillinam treatment group PFGE showed that among patients having a negative urine culture at the first follow-up 77% (46/60) had a relapse with the primary infecting E. coli strain and 23% (14/60) had reinfection with a new E. coli strain at the second follow-up. Among patients having E. coli at the first...

  14. Pulsed-field gel electrophoresis typing of Eschericia coli strains from samples collected before and after pivmecillinam or placebo treatment of uncomplicated community-acquired urinary tract infection in women

    DEFF Research Database (Denmark)

    Ejrnæs, K; Sandvang, D; Lundgren, Bettina

    2006-01-01

    ). The finding that the majority of UTIs at follow-up are caused by the primary infecting E. coli strain supports the theory of a vaginal and rectal reservoir but could also support the recent discovery that E. coli strains are able to persist in the bladder epithelium despite appropriate antibiotic treatment......The primary infecting Escherichia coli strains from 156 women with community-acquired uncomplicated urinary tract infection (UTI) randomized to pivmecillinam or placebo and the E. coli strains causing UTI at two follow-up visits were typed using pulsed-field gel electrophoresis (PFGE......). In the pivmecillinam treatment group PFGE showed that among patients having a negative urine culture at the first follow-up 77% (46/60) had a relapse with the primary infecting E. coli strain and 23% (14/60) had reinfection with a new E. coli strain at the second follow-up. Among patients having E. coli at the first...

  15. Brucella abortus-infected B cells induce osteoclastogenesis.

    Science.gov (United States)

    Pesce Viglietti, Ayelén Ivana; Arriola Benitez, Paula Constanza; Giambartolomei, Guillermo Hernán; Delpino, María Victoria

    2016-09-01

    Brucella abortus is an intracellular bacterium that establishes lifelong infections in livestock and humans although the mechanisms of its chronicity are poorly understood. Activated B cells have long lifespan and B. abortus infection activates B cells. Our results indicate that the direct infection of B cells with B. abortus induced matrix metalloproteinase-9 (MMP-9), receptor activator for NF κB ligand (RANKL), tumor necrosis factor (TNF)-α and interleukin (IL)-6 secretion. In addition, supernatants from B. abortus-infected B cells induced bone marrow-derived monocytes to undergo osteoclastogenesis. Using osteoprotegerin, RANKL's decoy receptor, we determined that RANKL is involved in osteoclastogenesis induced by supernatants from B. abortus-infected B cells. The results presented here shed light on how the interactions of B. abortus with B cells may have a role in the pathogenesis of brucellar osteoarticular disease. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  16. An epidemiological study on the drug resistance of Escherichia coli strains isolated from women patients with urinary tract infection in Shalamzar, Iran

    Directory of Open Access Journals (Sweden)

    Gholamreza Farnoosh

    2015-03-01

    Full Text Available Objective: To investigate drug resistance of various strains of Escherichia coli (E. coli bacteria isolated from female patients with urinary tracts infections (UTIs in Shalamzar, Iran. Methods: This study was conducted from April 2011 to April 2012 on 150 female patients with positive urine culture and 105 CFU/mL colony count. The pattern of antibiotic sensitivity was recognized using antibiogram by the disc diffusion method. Results: The results revealed that the predominant bacterium was E. coli (90%, followed by Klebsiella pneumonia (3%. Trimethoprim-sulfamethoxazole is the initial medicine to treat UTIs (without complications which demonstrated relatively poor activity against E. coli (with 40% sensitivity, though alternative medicines such as nitrofurantoin (97% sensitivity and ciprofloxacin (91% sensitivity showed good activity against E. coli as well. Conclusions: The findings emphasized the necessity of pursuing the investigations in national and local governments in order to retain the efficacy of treating UTIs using effective antibiotics.

  17. Escherichia coli and Salmonella ser. Saintpaul natural co-infection in a free-living ruddy ground dove (Columbina talpacoti: a case report

    Directory of Open Access Journals (Sweden)

    W.G.A. Bezerra

    Full Text Available ABSTRACT This study reports a co-infection of Escherichia coli and Salmonella in a free-living ruddy ground dove (Columbina talpacoti received at the Laboratory of Ornithological Studies of the State University of Ceará, Brazil. The bird presented diarrhea, leg paralysis and anorexia, and died shortly after. Necropsy was then performed and samples from lung, kidney, liver and intestine were collected for microbiological and histopathological analyses. Escherichia coli was isolated from cloacal swab, lung and kidney samples. Salmonella ser. Saintpaul was identified in liver and spleen samples. Escherichia coli isolates were tested for the presence of eight diagnostic genes for diarrheagenic pathotypes (STEC, ETEC, EPEC, EIEC, EAEC with conventional polymerase chain reaction (PCR. EAEC was detected in the lung and kidney, and STEC in the intestine. In conclusion, Columbina talpacoti is susceptible to enteroaggregative Escherichia coli and Salmonella ser. Saintpaul infection, which may have public health implications.

  18. Pathogenesis of Escherichia coli O157:H7 Strain 86-24 Following Oral Infection of BALB/c Mice with an Intact Commensal Flora

    Science.gov (United States)

    2010-01-01

    inocula of these organisms are also needed to achieve colonization and disease in monkeys [29] and rabbits [30]. Our data suggested that the predominate...SB. Escherichia coli 0157:H7 srrains associared wirh haemorrhagic colitis in rhe Unired Srares produce a Shigella dysenreriae 1 (SHIGA) like...611-20. (29) Kang G, Pulimood AB, Koshi R. Hull A, Acheson D. Rajan P. er al. A monkey model for enrerohemorrhagic Escherichia coli infection. j

  19. Multiple linear B-cell epitopes of classical swine fever virus glycoprotein E2 expressed in E.coli as multiple epitope vaccine induces a protective immune response

    Directory of Open Access Journals (Sweden)

    Wei Jian-Chao

    2011-07-01

    Full Text Available Abstract Classical swine fever is a highly contagious disease of swine caused by classical swine fever virus, an OIE list A pathogen. Epitope-based vaccines is one of the current focuses in the development of new vaccines against classical swine fever virus (CSFV. Two B-cell linear epitopes rE2-ba from the E2 glycoprotein of CSFV, rE2-a (CFRREKPFPHRMDCVTTTVENED, aa844-865 and rE2-b (CKEDYRYAISSTNEIGLLGAGGLT, aa693-716, were constructed and heterologously expressed in Escherichia coli as multiple epitope vaccine. Fifteen 6-week-old specified-pathogen-free (SPF piglets were intramuscularly immunized with epitopes twice at 2-week intervals. All epitope-vaccinated pigs could mount an anamnestic response after booster vaccination with neutralizing antibody titers ranging from 1:16 to 1:256. At this time, the pigs were subjected to challenge infection with a dose of 1 × 106 TCID50 virulent CSFV strain. After challenge infection, all of the rE2-ba-immunized pigs were alive and without symptoms or signs of CSF. In contrast, the control pigs continuously exhibited signs of CSF and had to be euthanized because of severe clinical symptoms at 5 days post challenge infection. The data from in vivo experiments shown that the multiple epitope rE2-ba shown a greater protection (similar to that of HCLV vaccine than that of mono-epitope peptide(rE2-a or rE2-b. Therefore, The results demonstrated that this multiple epitope peptide expressed in a prokaryotic system can be used as a potential DIVA (differentiating infected from vaccinated animals vaccine. The E.coli-expressed E2 multiple B-cell linear epitopes retains correct immunogenicity and is able to induce a protective immune response against CSFV infection.

  20. Data showing levels of interleukin-1β and nitric oxide in the plasma of uropathogenic E. coli infected UTI patients.

    Science.gov (United States)

    Verma, Vivek; Arora, Renu; Dhanda, Rakesh Singh; Gaind, Rajni; Yadav, Manisha

    2018-08-01

    Urinary tract infections (UTI) are a major cause of morbidity, affecting at least four million women worldwide, 65-75% of these infections are caused by Uropathogenic Escherichia coli (UPEC) (Foxman, 2010) [1]. Repertoire of virulence factors carried by UPEC provides the ability to precede urinary tract and additionally they provoke pro-inflammatory responses (Cirl et al., 2008; Verma et al., 2016) [2], [3]. In context to UPEC infected UTI patients, the levels of pro-inflammatory cytokine IL-1β and enzymatic antioxidant nitric oxide (NO) have not been reported worldwide till date, including India. In this data article, we report for the first time the levels of IL-1β and nitric oxide in the plasma of UPEC infected UTI patients. Data includes a profile of pro-inflammatory cytokine IL-1β and NO in the plasma of the confirmed UPEC infected UTI patients ( N  = 30) versus healthy controls ( N  = 40) from the present pilot study. The levels of IL-1β in plasma were significantly higher ( p  UTI patients (60.29 ± 1.1 μM) as compared to healthy controls (106.3 ± 8.75 μM).

  1. Synthesis of 99mTcV ≡ N-Pazufloxacin dithiocarbamate complex and biological evaluation in Wister rats artificially infected with Escherichia coli

    International Nuclear Information System (INIS)

    Syed Qaiser Shah; Muhammad Rafiullah Khan

    2011-01-01

    99m Tc ≡ N-Pazufloxacin dithiocarbamate ( 99m Tc ≡ N-PZN) complex was synthesized through the [ 99m Tc ≡ N] 2+ core and its aptness was radiochemically and biologically evaluated in terms of radiochemical purity (RCP) in saline, in vitro stability in serum, in vitro bacterial uptake and percent in vivo uptake in male Wister rats (MWR) artificially infected with alive and heat killed Escherichia coli (E. coli). The 99m Tc ≡ N-PZN complex showed more than 90% RCP up to 4 h after reconstitution in normal saline at room temperature with a maximum RCP value of 98.40 ± 0.28% (at 30 min). At 37 deg C in serum the complex showed stable behaviour up to 4 h with the appearance of 15.95% undesirable by products within 16 h of the incubation. The complex showed saturated in vitro binding with E. coli with a maximum uptake of 74.25 ± 0.50% (at 90 min). Normal biodistribution behaviour was noted with a sixfold higher accumulation in the muscle of the MWR, artificially infected with live E. coli as compared to the MWR infected with heat killed E. coli, inflamed and normal muscle. The high RCP in saline, elevated in vitro stability in serum, saturated in vitro binding with E. coli and the sixfold higher accumulation in the infected (live) muscle of the MWR as compared to the inflamed and normal muscle, recognized the aptness of the 99m Tc ≡ N-PZND complex as a prospective E. coli in vivo infection radiotracer. (author)

  2. Hemagglutination and biofilm formation as virulence markers of uropathogenic Escherichia coli in acute urinary tract infections and urolithiasis

    Directory of Open Access Journals (Sweden)

    Uma B Maheswari

    2013-01-01

    Full Text Available Introduction: Urinary tract infections (UTI are a major public health concern in developing countries. Most UTIs are caused by E. coli, accounting for up to 90% of community-acquired UTIs (CAUTI. Recurrent UTI is considered as a major risk factor for urolithiasis. Virulence factors like adhesins and biofilm have been extensively studied by authors on UPEC isolated from recurrent UTI.The studies on isolates from infection stones in kidney are scanty . In a prospective study, we aimed to determine the expression of Haemagglutinins, (Type 1 and P fimbriae , Biofilm production and resistance pattern to common antibiotics of Uropathogenic E.coli (UPEC isolates from Community acquired Acute Urinary Tract Infection(CAUTI and Urolithiasis. Materials and Methods: A total of 43 UPEC isolates , 23 mid-stream urine (MSU samples from patients with CAUTI attending Out Patient Departments and 20 from renal calculi of urolithiasis patients at the time of Percutaneous nephrolithostomy (PCNL were included in the study and the expression of Haemagglutinins,(Type 1 and P fimbriae , Biofilm production and resistance pattern to common antibiotics was assessed. Results: A total of 43 UPEC isolates 23 from CAUTI and 20 from renal calculi were tested for production of biofilm and hemagglutinins. In CAUTI, biofilm producers were 56.52% and hemagglutinins were detected in all isolates 100%. In urolithiasis, biofilm producers were 100% but hemagglutinins were detected only in 70% of isolates. All isolates were resistant to multiple antibiotics used. CAUTI isolates were susceptible to 3 rd generation cephalosporins, whereas urolithiasis isolates were resistant to 3 rd generation cephalosporins and 25% were Extended Spectrum Beta Lactamases ESBL producers. Conclusions: HA mediated by type 1 fimbriae plays an important role in CAUTI (P < 0.001 highly significant, whereas, in chronic conditions like urolithiasis, biofilm plays an important role in persistence of infection and

  3. Development of a dual vaccine for prevention of Brucella abortus infection and Escherichia coli O157:H7 intestinal colonization.

    Science.gov (United States)

    Iannino, Florencia; Herrmann, Claudia K; Roset, Mara S; Briones, Gabriel

    2015-05-05

    Zoonoses that affect human and animal health have an important economic impact. In the study now presented, a bivalent vaccine has been developed that has the potential for preventing the transmission from cattle to humans of two bacterial pathogens: Brucella abortus and Shiga toxin-producing Escherichia coli (STEC). A 66kDa chimeric antigen, composed by EspA, Intimin, Tir, and H7 flagellin (EITH7) from STEC, was constructed and expressed in B. abortus Δpgm vaccine strain (BabΔpgm). Mice orally immunized with BabΔpgm(EITH7) elicited an immune response with the induction of anti-EITH7 antibodies (IgA) that clears an intestinal infection of E. coli O157:H7 three times faster (t=4 days) than mice immunized with BabΔpgm carrier strain (t=12 days). As expected, mice immunized with BabΔpgm(EITH7) strain also elicited a protective immune response against B. abortus infection. A Brucella-based vaccine platform is described capable of eliciting a combined protective immune response against two bacterial pathogens with diverse lifestyles-the intracellular pathogen B. abortus and the intestinal extracellular pathogen STEC. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Antimicrobial Drug-Resistant Shiga Toxin-Producing Escherichia coli Infections, Michigan, USA.

    Science.gov (United States)

    Mukherjee, Sanjana; Mosci, Rebekah E; Anderson, Chase M; Snyder, Brian A; Collins, James; Rudrik, James T; Manning, Shannon D

    2017-09-01

    High frequencies of antimicrobial drug resistance were observed in O157 and non-O157 Shiga toxin-producing E. coli strains recovered from patients in Michigan during 2010-2014. Resistance was more common in non-O157 strains and independently associated with hospitalization, indicating that resistance could contribute to more severe disease outcomes.

  5. The E. coli immunosorbent as used in serodiagnosis of Legionella infections studied by crossed immunoelectrophoresis

    DEFF Research Database (Denmark)

    Bangsborg, Jette Marie; Friis-Møller, A; Rechnitzer, C

    1988-01-01

    In this study we investigated an immunosorbent, E. coli blocking fluid (BF), proposed for use in the Legionella Indirect Fluorescent Antibody Test (IFA). With crossed immunoelectrophoresis (CIE) of clinically relevant Legionella species, only one heat-stable antigen (no. 1) cross...

  6. Lethal Nipah virus infection induces rapid overexpression of CXCL10.

    Directory of Open Access Journals (Sweden)

    Cyrille Mathieu

    Full Text Available Nipah virus (NiV is a recently emerged zoonotic Paramyxovirus that causes regular outbreaks in East Asia with mortality rate exceeding 75%. Major cellular targets of NiV infection are endothelial cells and neurons. To better understand virus-host interaction, we analyzed the transcriptome profile of NiV infection in primary human umbilical vein endothelial cells. We further assessed some of the obtained results by in vitro and in vivo methods in a hamster model and in brain samples from NiV-infected patients. We found that NiV infection strongly induces genes involved in interferon response in endothelial cells. Among the top ten upregulated genes, we identified the chemokine CXCL10 (interferon-induced protein 10, IP-10, an important chemoattractant involved in the generation of inflammatory immune response and neurotoxicity. In NiV-infected hamsters, which develop pathology similar to what is seen in humans, expression of CXCL10 mRNA was induced in different organs with kinetics that followed NiV replication. Finally, we showed intense staining for CXCL10 in the brain of patients who succumbed to lethal NiV infection during the outbreak in Malaysia, confirming induction of this chemokine in fatal human infections. This study sheds new light on NiV pathogenesis, indicating the role of CXCL10 during the course of infection and suggests that this chemokine may serve as a potential new marker for lethal NiV encephalitis.

  7. Uropathogenic Escherichia coli metabolite-dependent quiescence and persistence may explain antibiotic tolerance during urinary tract infection

    DEFF Research Database (Denmark)

    Leatham-Jensen, Mary P.; Mokszycki, Matthew E.; Rowley, David C.

    2016-01-01

    infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection...... of urothelial transitional cells in the bladder, UPEC appear to enter a nongrowing quiescent intracellular state that is thought to serve as a reservoir responsible for recurrent UTIs. Here, we report that many UPEC strains enter a quiescent state when ≤10(6) CFU are seeded on glucose M9 minimal medium agar...

  8. Experimental infection with Escherichia coli 0149 : F4ac in weaned piglets

    DEFF Research Database (Denmark)

    Jensen, Gerda M.; Frydendahl, Kai; Svendsen, Ove

    2006-01-01

    adhesion test made after slaughter of piglets. However, in an experimental infection study with the purpose to obtain diarrhoeic piglets, it would be an advantage to test for susceptibility prior to experimentation. The Mucin 4 gene on porcine chromosome 13 has been proposed as a candidate gene...... for the production of the specific ETEC F4ab/ac receptor, and a DNA marker-based test has been developed to allow genotyping for ETEC F4ab/ac resistance/susceptibility [Jorgensen, C.B., Cirera, S., Archibald, A.L., Anderson, L., Fredholm, M., Edfors-Lilja, I., 2004. Porcine polymorphisms and methods for detecting...... them. International application published under the patent cooperation treaty (PCT). PCT/DK2003/000807 or WO2004/048606-A2]. The aim of this study was to test an experimental model for ETEC O149:F4ac-induced diarrhoea in piglets, selected for susceptibility towards ETEC O149:F4ac adhesion prior...

  9. Deletions induced by gamma rays in the genome of Escherichia coli

    International Nuclear Information System (INIS)

    Raha, Manidipa; Hutchinson, Franklin

    1991-01-01

    An Escherichia coli lysogen was constructed with a lambda phage bearing a lacZ gene surrounded by about 100 x 10 3 base-pairs of dispensable DNA. The lacZ mutants induced by gamma rays in this lysogen were more than 10% large deletions, ranging in size from 0.6 x 10 -3 to 70 x 10 3 base-pairs. These deletions were centered, not on lacZ, but on a ColE1 origin of DNA replication located 1.2 x 10 3 bases downstream from lacZ, suggesting that this origin of replication was involved in the process by which deletions were formed. In agreement with this hypothesis, a lysogen of the same phage without the ColE1 origin showed a very much lower percentage of radiation-induced deletions, as did a second lysogen of a lambda phage without any known plasmid origin of replication. Indirect evidence is presented for radiation-induced deletions centered on the lambda origin of DNA replication in a lysogen. (author)

  10. Cheese whey-induced high-cell-density production of recombinant proteins in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Neubauer Peter

    2003-04-01

    Full Text Available Abstract Background Use of lactose-rich concentrates from dairy processes for the induction of recombinant gene's expression has not received much attention although they are interesting low cost substrates for production of recombinant enzymes. Applicability of dairy waste for induction of recombinant genes in Escherichia coli was studied. Clones expressing Lactobacillus phage muramidase and Lactobacillus alcohol dehydrogenase were used for the experiments. Results Shake flask cultivations in mineral salt medium showed that cheese whey or deproteinised whey induced gene expression as efficiently as IPTG (isopropyl-β-D-thiogalactopyranoside or pure lactose. Addition of yeast extract or proteolytically degraded whey proteins did not improve the recombinant protein yield. In contrast, addition of yeast extract to the well-balanced mineral salt medium decreased the product yield. Feeding with glycerol provided sufficient amount of easily assimilable carbon source during the induction period without preventing lactose intake and induction by lactose. High-cell-density fed-batch cultivations showed that product yields comparable to IPTG-induction can be achieved by feeding bacteria with a mixture of glycerol and concentrated whey permeate during the induction. Conclusion Whey and concentrated whey permeate can be applied as an alternative inducer in recombinant high-cell-density fed-batch fermentations. The yield of the recombinant product was comparable to fermentations induced by IPTG. In low-cell-density shake flask experiments the yield was higher with whey or whey permeate than with IPTG.

  11. Single d(ApG)/cis-diamminedichloroplatinum(II) adduct-induced mutagenesis in Escherichia coli

    International Nuclear Information System (INIS)

    Burnouf, D.; Fuchs, R.P.P.; Gauthier, C.; Chottard, J.C.

    1990-01-01

    The mutation spectrum induced by the widely used antitumor drug cis-diamminedichloroplatinum(II) (cis-DDP) showed that cisDDP[d(ApG)] adducts, although they account for only 25% of the lesions formed are ∼5 times more mutagenic than the major GG adduct. The authors report the construction of vectors bearing a single cisDDP[d(ApG)] lesion and their use in mutagenesis experiments in Escherichia coli. The mutagenic processing of the lesion is found to depend strictly on induction of the SOS system of the bacterial host cells. In SOS-induced cells, mutation frequencies of 1-2% were detected. All these mutations are targeted to the 5' base of the adduct. Single A → T transversions are mainly observed (80%), whereas A → G transitions account for 10% of the total mutations. Tandem base-pair substitutions involving the adenine residue and the thymine residue immediately 5' to the adduct occur at a comparable frequency (10%). No selective loss of the strand bearing the platinum adduct was seen, suggesting that, in vivo, cisDDP[d(ApG)] adducts are not blocking lesions. The high mutation specificity of cisDDP-[d(ApG)]-induced mutagenesis is discussed in relation to structural data

  12. A Stress-Induced Bias in the Reading of the Genetic Code in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Adi Oron-Gottesman

    2016-11-01

    Full Text Available Escherichia coli mazEF is an extensively studied stress-induced toxin-antitoxin (TA system. The toxin MazF is an endoribonuclease that cleaves RNAs at ACA sites. Thereby, under stress, the induced MazF generates a stress-induced translation machinery (STM, composed of MazF-processed mRNAs and selective ribosomes that specifically translate the processed mRNAs. Here, we further characterized the STM system, finding that MazF cleaves only ACA sites located in the open reading frames of processed mRNAs, while out-of-frame ACAs are resistant. This in-frame ACA cleavage of MazF seems to depend on MazF binding to an extracellular-death-factor (EDF-like element in ribosomal protein bS1 (bacterial S1, apparently causing MazF to be part of STM ribosomes. Furthermore, due to the in-frame MazF cleavage of ACAs under stress, a bias occurs in the reading of the genetic code causing the amino acid threonine to be encoded only by its synonym codon ACC, ACU, or ACG, instead of by ACA.

  13. The co-transcriptome of uropathogenic Escherichia coli-infected mouse macrophages reveals new insights into host-pathogen interactions

    KAUST Repository

    Mavromatis, Charalampos Harris; Bokil, Nilesh J.; Totsika, Makrina; Kakkanat, Asha; Schaale, Kolja; Cannistraci, Carlo V.; Ryu, Tae Woo; Beatson, Scott A.; Ulett, Glen C.; Schembri, Mark A.; Sweet, Matthew J.; Ravasi, Timothy

    2015-01-01

    Urinary tract infections (UTI) are among the most common infections in humans. Uropathogenic Escherichia coli (UPEC) can invade and replicate within bladder epithelial cells, and some UPEC strains can also survive within macrophages. To understand the UPEC transcriptional programme associated with intramacrophage survival, we performed host–pathogen co-transcriptome analyses using RNA sequencing. Mouse bone marrow-derived macrophages (BMMs) were challenged over a 24 h time course with two UPEC reference strains that possess contrasting intramacrophage phenotypes: UTI89, which survives in BMMs, and 83972, which is killed by BMMs. Neither of these strains caused significant BMM cell death at the low multiplicity of infection that was used in this study. We developed an effective computational framework that simultaneously separated, annotated and quantified the mammalian and bacterial transcriptomes. Bone marrow-derived macrophages responded to the two UPEC strains with a broadly similar gene expression programme. In contrast, the transcriptional responses of the UPEC strains diverged markedly from each other. We identified UTI89 genes up-regulated at 24 h post-infection, and hypothesized that some may contribute to intramacrophage survival. Indeed, we showed that deletion of one such gene (pspA) significantly reduced UTI89 survival within BMMs. Our study provides a technological framework for simultaneously capturing global changes at the transcriptional level in co-cultures, and has generated new insights into the mechanisms that UPEC use to persist within the intramacrophage environment.

  14. The co-transcriptome of uropathogenic Escherichia coli-infected mouse macrophages reveals new insights into host-pathogen interactions

    KAUST Repository

    Mavromatis, Charalampos Harris

    2015-01-24

    Urinary tract infections (UTI) are among the most common infections in humans. Uropathogenic Escherichia coli (UPEC) can invade and replicate within bladder epithelial cells, and some UPEC strains can also survive within macrophages. To understand the UPEC transcriptional programme associated with intramacrophage survival, we performed host–pathogen co-transcriptome analyses using RNA sequencing. Mouse bone marrow-derived macrophages (BMMs) were challenged over a 24 h time course with two UPEC reference strains that possess contrasting intramacrophage phenotypes: UTI89, which survives in BMMs, and 83972, which is killed by BMMs. Neither of these strains caused significant BMM cell death at the low multiplicity of infection that was used in this study. We developed an effective computational framework that simultaneously separated, annotated and quantified the mammalian and bacterial transcriptomes. Bone marrow-derived macrophages responded to the two UPEC strains with a broadly similar gene expression programme. In contrast, the transcriptional responses of the UPEC strains diverged markedly from each other. We identified UTI89 genes up-regulated at 24 h post-infection, and hypothesized that some may contribute to intramacrophage survival. Indeed, we showed that deletion of one such gene (pspA) significantly reduced UTI89 survival within BMMs. Our study provides a technological framework for simultaneously capturing global changes at the transcriptional level in co-cultures, and has generated new insights into the mechanisms that UPEC use to persist within the intramacrophage environment.

  15. Mapping Stress-Induced Changes in Autoinducer AI-2 Production in Chemostat-Cultivated Escherichia coli K-12

    Science.gov (United States)

    DeLisa, Matthew P.; Valdes, James J.; Bentley, William E.

    2001-01-01

    Numerous gram-negative bacteria employ a cell-to-cell signaling mechanism, termed quorum sensing, for controlling gene expression in response to population density. Recently, this phenomenon has been discovered in Escherichia coli, and while pathogenic E. coli utilize quorum sensing to regulate pathogenesis (i.e., expression of virulence genes), the role of quorum sensing in nonpathogenic E. coli is less clear, and in particular, there is no information regarding the role of quorum sensing during the overexpression of recombinant proteins. The production of autoinducer AI-2, a signaling molecule employed by E. coli for intercellular communication, was studied in E. coli W3110 chemostat cultures using a Vibrio harveyi AI-2 reporter assay (M. G. Surrette and B. L. Bassler, Proc. Natl. Acad. Sci. USA 95:7046–7050, 1998). Chemostat cultures enabled a study of AI-2 regulation through steady-state and transient responses to a variety of environmental stimuli. Results demonstrated that AI-2 levels increased with the steady-state culture growth rate. In addition, AI-2 increased following pulsed addition of glucose, Fe(III), NaCl, and dithiothreitol and decreased following aerobiosis, amino acid starvation, and isopropyl-β-d-thiogalactopyranoside-induced expression of human interleukin-2 (hIL-2). In general, the AI-2 responses to several perturbations were indicative of a shift in metabolic activity or state of the cells induced by the individual stress. Because of our interest in the expression of heterologous proteins in E. coli, the transcription of four quorum-regulated genes and 20 stress genes was mapped during the transient response to induced expression of hIL-2. Significant regulatory overlap was revealed among several stress and starvation genes and known quorum-sensing genes. PMID:11292813

  16. A Selected Lactobacillus rhamnosus Strain Promotes EGFR-Independent Akt Activation in an Enterotoxigenic Escherichia coli K88-Infected IPEC-J2 Cell Model.

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    Full Text Available Enterotoxigenic Escherichia coli (ETEC are important intestinal pathogens that cause diarrhea in humans and animals. Although probiotic bacteria may protect against ETEC-induced enteric infections, the underlying mechanisms are unknown. In this study, porcine intestinal epithelial J2 cells (IPEC-J2 were pre-incubated with and without Lactobacillus rhamnosus ATCC 7469 and then exposed to F4+ ETEC. Increases in TLR4 and NOD2 mRNA expression were observed at 3 h after F4+ ETEC challenge, but these increases were attenuated by L. rhamnosus treatment. Expression of TLR2 and NOD1 mRNA was up-regulated in cells pre-treated with L. rhamnosus. Pre-treatment with L. rhamnosus counteracted F4+ ETEC-induced increases in TNF-α concentration. Increased PGE2. concentrations were observed in cells infected with F4+ ETEC and in cells treated with L. rhamnosus only. A decrease in phosphorylated epidermal growth factor receptor (EGFR was observed at 3 h after F4+ ETEC challenge in cells treated with L. rhamnosus. Pre-treatment with L. rhamnosus enhanced Akt phosphorylation and increased ZO-1 and occludin protein expression. Our findings suggest that L. rhamnosus protects intestinal epithelial cells from F4+ ETEC-induced damage, partly through the anti-inflammatory response involving synergism between TLR2 and NOD1. In addition, L. rhamnosus promotes EGFR-independent Akt activation, which may activate intestinal epithelial cells in response to bacterial infection, in turn increasing tight junction integrity and thus enhancing the barrier function and restricting pathogen invasion. Pre-incubation with L. rhamnosus was superior to co-incubation in reducing the adhesion of F4+ ETEC to IPEC-J2 cells and subsequently attenuating F4+ ETEC-induced mucin layer destruction and suppressing apoptosis. Our data indicate that a selected L. rhamnosus strain interacts with porcine intestinal epithelial cells to maintain the epithelial barrier and promote intestinal epithelial

  17. A Selected Lactobacillus rhamnosus Strain Promotes EGFR-Independent Akt Activation in an Enterotoxigenic Escherichia coli K88-Infected IPEC-J2 Cell Model.

    Science.gov (United States)

    Zhang, Wei; Zhu, Yao-Hong; Yang, Jin-Cai; Yang, Gui-Yan; Zhou, Dong; Wang, Jiu-Feng

    2015-01-01

    Enterotoxigenic Escherichia coli (ETEC) are important intestinal pathogens that cause diarrhea in humans and animals. Although probiotic bacteria may protect against ETEC-induced enteric infections, the underlying mechanisms are unknown. In this study, porcine intestinal epithelial J2 cells (IPEC-J2) were pre-incubated with and without Lactobacillus rhamnosus ATCC 7469 and then exposed to F4+ ETEC. Increases in TLR4 and NOD2 mRNA expression were observed at 3 h after F4+ ETEC challenge, but these increases were attenuated by L. rhamnosus treatment. Expression of TLR2 and NOD1 mRNA was up-regulated in cells pre-treated with L. rhamnosus. Pre-treatment with L. rhamnosus counteracted F4+ ETEC-induced increases in TNF-α concentration. Increased PGE2. concentrations were observed in cells infected with F4+ ETEC and in cells treated with L. rhamnosus only. A decrease in phosphorylated epidermal growth factor receptor (EGFR) was observed at 3 h after F4+ ETEC challenge in cells treated with L. rhamnosus. Pre-treatment with L. rhamnosus enhanced Akt phosphorylation and increased ZO-1 and occludin protein expression. Our findings suggest that L. rhamnosus protects intestinal epithelial cells from F4+ ETEC-induced damage, partly through the anti-inflammatory response involving synergism between TLR2 and NOD1. In addition, L. rhamnosus promotes EGFR-independent Akt activation, which may activate intestinal epithelial cells in response to bacterial infection, in turn increasing tight junction integrity and thus enhancing the barrier function and restricting pathogen invasion. Pre-incubation with L. rhamnosus was superior to co-incubation in reducing the adhesion of F4+ ETEC to IPEC-J2 cells and subsequently attenuating F4+ ETEC-induced mucin layer destruction and suppressing apoptosis. Our data indicate that a selected L. rhamnosus strain interacts with porcine intestinal epithelial cells to maintain the epithelial barrier and promote intestinal epithelial cell activation in

  18. Frequency of escherichia coli in patients with community acquired urinary tract infection and their resistance pattern against some commonly used anti bacterials

    International Nuclear Information System (INIS)

    Ahmad, W.; Jamshed, F.; Ahmad, W.

    2015-01-01

    Urinary tract infection (UTI) is a very common health problem and Escherichia coli (E coli) are the most common organisms associated with community acquired UTI. Unfortunately these bacteria have developed extensive resistance against most of the commonly used anti-bacterials. The objective of this study was to determine the frequency and resistance pattern of E coli in patients of community acquired UTI in an area in northern part of Pakistan. Methods: Urine specimens were collected from patients who were clinically diagnosed as community acquired UTI. Urine routine examination (Urine RE) was done and samples positive for UTI (Pus cells >10/High Power Field) were included in the study. These samples were inoculated on Eosin Methylene Blue (EMB) agar plates and incubated at 37 degree C for 36 hours. Suspected colonies were then inoculated further on EMB plates for pure cultures of E coli characterized by certain morphological characteristics. IMViC was applied for the confirmation of E coli. In vitro antibiotic susceptibility tests of E coli were performed with standardized commercial susceptibility discs (OXOID). Results: Out of 50 specimens, positive for UTI by urine RE, 20 showed pure growth of E coli on culture (40%). The majority of the isolates (28%; n=14) were from women while only 12% (n=6) were from men. Escherichia coli showed a high rate of resistance towards Ampicillin (90%), Tetracycline (70%), Erythromycin (70%) and Trimethoprim-Sulfamethoxazole (55%). Sparfloxacin showed better results (45%) than ciprofloxacin (50%). Out of 20 E coli isolates, two (10%) were resistant to all the antibacterials except chloramphenicol, eight isolates (40%) showed resistance to six or more than six while 14 (70%) were resistant to four or more than four drugs. Conclusion: Rate of resistance of E coli against commonly used antibacterials was quite high and majority of the strains showed multidrug resistance. (author)

  19. Pulsed-field gel electrophoresis typing of Escherichia coli strains from samples collected before and after pivmecillinam or placebo treatment of uncomplicated community-acquired urinary tract infection in women

    DEFF Research Database (Denmark)

    Ejrnaes, Karen; Sandvang, Dorthe; Lundgren, Bettina

    2006-01-01

    The primary infecting Escherichia coli strains from 156 women with community-acquired uncomplicated urinary tract infection (UTI) randomized to pivmecillinam or placebo and the E. coli strains causing UTI at two follow-up visits were typed using pulsed-field gel electrophoresis (PFGE......). The finding that the majority of UTIs at follow-up are caused by the primary infecting E. coli strain supports the theory of a vaginal and rectal reservoir but could also support the recent discovery that E. coli strains are able to persist in the bladder epithelium despite appropriate antibiotic treatment......, constituting a reservoir for recurrent UTI....

  20. Pulsed-field gel electrophoresis typing of Eschericia coli strains from samples collected before and after pivmecillinam or placebo treatment of uncomplicated community-acquired urinary tract infection in women

    DEFF Research Database (Denmark)

    Ejrnæs, K; Sandvang, D; Lundgren, Bettina

    2006-01-01

    The primary infecting Escherichia coli strains from 156 women with community-acquired uncomplicated urinary tract infection (UTI) randomized to pivmecillinam or placebo and the E. coli strains causing UTI at two follow-up visits were typed using pulsed-field gel electrophoresis (PFGE......). The finding that the majority of UTIs at follow-up are caused by the primary infecting E. coli strain supports the theory of a vaginal and rectal reservoir but could also support the recent discovery that E. coli strains are able to persist in the bladder epithelium despite appropriate antibiotic treatment......, constituting a reservoir for recurrent UTI....

  1. Absence of ultraviolet-inducible DNA polymerase I-like activity in Escherichia coli strains harbouring R plasmids

    International Nuclear Information System (INIS)

    Upton, C.; Pinney, R.J.

    1981-01-01

    No DNA polymerase I-like activity was found associated with the ultraviolet (u.v.)-protecting plasmids R205, R46 or pKM101 in either uninduced or u.v.-induced wild-type or DNA polymerase I-deficient strains of Escherichia coli. Nor was any plasmid-associated polymerase activity detectable in similar systems containing u.v.-irradiated DNA as template. However, plasmids R205, R46 and pKM 101 still increased survival and mutagenesis of the polymerase I-deficient E. coli strain after u.v. irradiation. (author)

  2. An outbreak of Vero cytotoxin producing Escherichia coli O157 infection associated with takeaway sandwiches.

    LENUS (Irish Health Repository)

    McDonnell, R J

    1997-12-12

    An outbreak of food poisoning due to Escherichia coli O157 phage type 2 Vero cytotoxin 2 affected 26 people in southern counties of England in May and June 1995. The organism was isolated from faecal specimens from 23 patients, 16 of whom lived in Dorset and seven in Hampshire. Isolates were indistinguishable by phage typing, Vero cytotoxin gene typing, restriction fragment length polymorphism, and pulsed field gel electrophoresis. Three associated cases, linked epidemiologically to the outbreak, were confirmed serologically by detection of antibodies to E. coli O157 lipopolysaccharide. Twenty-two of the 26 patients were adults: four were admitted to hospital with haemorrhagic colitis. Four cases were children: two were admitted to hospital with haemolytic uraemic syndrome (HUS). There were no deaths. Although E. coli O157 was not isolated from any food samples, illness was associated with having eaten cold meats in sandwiches bought from two sandwich producers, in Weymouth and in Portsmouth. Both shops were supplied by the same wholesaler, who kept no records and obtained cooked meats from several sources in packs that did not carry adequate identification marks. It was, therefore, impossible to trace back to the original producer or to investigate further to determine the origin of contamination with E. coli O157. To protect the public health it is essential that all wholesale packs of ready-to-eat food carry date codes and the producer\\'s identification mark. Detailed record keeping should be part of hazard analysis critical control point (HACCP) systems and should be maintained throughout the chain of distribution from the producer to retail outlets.

  3. Population-based incidence and comparative demographics of community-associated and healthcare-associated Escherichia coli bloodstream infection in Auckland, New Zealand, 2005 – 2011

    Science.gov (United States)

    2013-01-01

    Background Escherichia coli is a major human pathogen, both in community and healthcare settings. To date however, relatively few studies have defined the population burden of E. coli bloodstream infections. Such information is important in informing strategies around treatment and prevention of these serious infections. Against this background, we performed a retrospective, population-based observational study of all cases of E. coli bacteremia in patients presenting to our hospital between January 2005 and December 2011. Methods Auckland District Health Board is a tertiary-level, university-affiliated institution serving a population of approximately 500,000, within a larger metropolitan population of 1.4 million. We identified all patients with an episode of bloodstream infection due to E. coli over the study period. A unique episode was defined as the first positive E. coli blood culture taken from the same patient within a thirty-day period. Standard definitions were used to classify episodes into community- or healthcare-associated E. coli bacteremia. Demographic information was obtained for all patients, including: age; gender; ethnicity; length of stay (days); requirement for intensive care admission and all-cause, in-patient mortality. Results A total of 1507 patients had a unique episode of E. coli bacteremia over the study period. The overall average annual incidence of E. coli bacteremia was 52 per 100,000 population, and was highest in the under one year and over 65-year age groups. When stratified by ethnicity, rates were highest in Pacific Peoples and Māori (83 and 62 per 100,000 population respectively). The incidence of community-onset E. coli bacteremia increased significantly over the study period. The overall in-hospital mortality rate was 9% (135/1507), and was significantly higher in patients who had a hospital-onset E. coli bacteremia. Conclusions Our work provides valuable baseline data on the incidence of E. coli bacteremia in our locale

  4. Population-based incidence and comparative demographics of community-associated and healthcare-associated Escherichia coli bloodstream infection in Auckland, New Zealand, 2005-2011.

    Science.gov (United States)

    Williamson, Deborah A; Lim, Alwin; Wiles, Siouxsie; Roberts, Sally A; Freeman, Joshua T

    2013-08-21

    Escherichia coli is a major human pathogen, both in community and healthcare settings. To date however, relatively few studies have defined the population burden of E. coli bloodstream infections. Such information is important in informing strategies around treatment and prevention of these serious infections. Against this background, we performed a retrospective, population-based observational study of all cases of E. coli bacteremia in patients presenting to our hospital between January 2005 and December 2011. Auckland District Health Board is a tertiary-level, university-affiliated institution serving a population of approximately 500,000, within a larger metropolitan population of 1.4 million. We identified all patients with an episode of bloodstream infection due to E. coli over the study period. A unique episode was defined as the first positive E. coli blood culture taken from the same patient within a thirty-day period. Standard definitions were used to classify episodes into community- or healthcare-associated E. coli bacteremia. Demographic information was obtained for all patients, including: age; gender; ethnicity; length of stay (days); requirement for intensive care admission and all-cause, in-patient mortality. A total of 1507 patients had a unique episode of E. coli bacteremia over the study period. The overall average annual incidence of E. coli bacteremia was 52 per 100,000 population, and was highest in the under one year and over 65-year age groups. When stratified by ethnicity, rates were highest in Pacific Peoples and Māori (83 and 62 per 100,000 population respectively). The incidence of community-onset E. coli bacteremia increased significantly over the study period. The overall in-hospital mortality rate was 9% (135/1507), and was significantly higher in patients who had a hospital-onset E. coli bacteremia. Our work provides valuable baseline data on the incidence of E. coli bacteremia in our locale. The incidence was higher that that

  5. Escherichia coli Isolates from Broiler Chicken Meat, Broiler Chickens, Pork, and Pigs Share Phylogroups and Antimicrobial Resistance with Community-Dwelling Humans and Patients with Urinary Tract Infection

    DEFF Research Database (Denmark)

    Jakobsen, L.; Kurbasic, A.; Skjot-Rasmussen, L.

    2010-01-01

    Escherichia coli is the most common cause of urinary tract infection (UTI). Phylogroup B2 and D isolates are associated with UTI. It has been proposed that E. coli causing UTI could have an animal origin. The objective of this study was to investigate the phylogroups and antimicrobial resistance......, and their possible associations in E. coli isolates from patients with UTI, community-dwelling humans, broiler chicken meat, broiler chickens, pork, and pigs in Denmark. A total of 964 geographically and temporally matched E. coli isolates from UTI patients (n = 102), community-dwelling humans (n = 109), Danish (n...... resistance data, we found that UTI isolates always grouped with isolates from meat and/or animals. We detected B2 and D isolates, that are associated to UTI, among isolates from broiler chicken meat, broiler chickens, pork, and pigs. Although B2 isolates were found in low prevalences in animals and meat...

  6. YghJ, the secreted metalloprotease of pathogenic E. coli induces hemorrhagic fluid accumulation in mouse ileal loop.

    Science.gov (United States)

    Tapader, Rima; Bose, Dipro; Pal, Amit

    2017-04-01

    YghJ, also known as SslE (Secreted and surface associated lipoprotein) is a cell surface associated and secreted lipoprotein harbouring M60 metalloprotease domain. Though the gene is known to be conserved among both pathogenic and commensal Escherichia coli isolates, the expression and secretion of YghJ was found to be higher among diverse E. coli pathotypes. YghJ, secreted from intestinal pathogens such as enterotoxigenic E. coli (ETEC) and enteropathogenic E. coli (EPEC) has been demonstrated to possess mucinase activity and hence facilitates colonization of these enteric pathogens to intestinal epithelial cells. Importantly, YghJ is also reported to be secreted from extraintestinal pathogenic E. coli isolates. In our previous study we have shown that YghJ, purified from a neonatal septicemic E. coli isolate could trigger induction of various proinflammatory cytokines in vitro. This led us to investigate the role of YghJ in causing in vivo tissue hemorrhage. In the present study, we validate the earlier in vitro finding and have showed that YghJ can cause extensive tissue damage in mouse ileum and is also able to induce significant fluid accumulation in a dose dependent manner in a mouse ileal loop (MIL) assay. Hence, our present study not only confirms the pathogenic potential of YghJ in sepsis pathophysiology but also indicates the enterotoxic ability of YghJ which makes it an important virulence determinant of intestinal pathogenic E. coli. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Supercritical CO2 induces marked changes in membrane phospholipids composition in Escherichia coli K12.

    Science.gov (United States)

    Tamburini, Sabrina; Anesi, Andrea; Ferrentino, Giovanna; Spilimbergo, Sara; Guella, Graziano; Jousson, Olivier

    2014-06-01

    Supercritical carbon dioxide (SC-CO2) treatment is one of the most promising alternative techniques for pasteurization of both liquid and solid food products. The inhibitory effect of SC-CO2 on bacterial growth has been investigated in different species, but the precise mechanism of action remains unknown. Membrane permeabilization has been proposed to be the first event in SC-CO2-mediated inactivation. Flow cytometry, high performance liquid chromatography–electrospray ionization–mass spectrometry and NMR analyses were performed to investigate the effect of SC-CO2 treatment on membrane lipid profile and membrane permeability in Escherichia coli K12. After 15 min of SC-CO2 treatment at 120 bar and 35 °C, the majority of bacterial cells dissipated their membrane potential (95 %) and lost membrane integrity, as 81 % become partially permeabilized and 18 % fully permeabilized. Membrane permeabilization was associated with a 20 % decrease in bacterial biovolume and to a strong (>50 %) reduction in phosphatidylglycerol (PG) membrane lipids, without altering the fatty acid composition and the degree of unsaturation of acyl chains. PGs are thought to play an important role in membrane stability, by reducing motion of phosphatidylethanolamine (PE) along the membrane bilayer, therefore promoting the formation of inter-lipid hydrogen bonds. In addition, the decrease in intracellular pH induced by SC-CO2 likely alters the chemical properties of phospholipids and the PE/PG ratio. Biophysical effects of SC-CO2 thus cause a strong perturbation of membrane architecture in E. coli, and such alterations are likely associated with its strong inactivation effect.

  8. Pharmacokinetics of amoxicillin administered in drinking water to recently weaned 3- to 4-week-old pigs with diarrhea experimentally induced by Escherichia coli O149 : F4

    DEFF Research Database (Denmark)

    Jensen, G.M.; Lykkesfeldt, J.; Frydendahl, K.

    2006-01-01

    Objective-To measure effects of Escherichia coli 0149:F4-induced diarrhea on water consumption and pharmacokinetics of amoxicillin after administration in drinking water. Animals-24 recently weaned 24- to 28-day-old crossbred pigs. Procedure-10 pigs were inoculated with E coli O149:F4; all 10 pigs...... of amoxicillin may be appropriate for administration in drinking water during a 4-hour period on the first day that pigs have diarrhea attributable to E coli 0149:F4....

  9. Delayed ultraviolet light-induced cessation of respiration by inadequate aeration of Escherichia coli

    International Nuclear Information System (INIS)

    Joshi, J.G.; Swenson, P.A.; Schenley, R.L.

    1977-01-01

    Inadequately aerated Escherichia coli B/r cultures did not shut their respiration off 60 min after ultraviolet light (52 J/m 2 at 254 nm) as they did when well supplied with oxygen. Since cessation of respiration is associated with cell death, the result suggested that oxygen toxicity by superoxide radicals generated by cell metabolism might be responsible for cell death. The specific activity of superoxide dismutase, which scavenges O 2 - radicals, increased twofold after 90 min of adequate aeration, but the specific activity of catalase remained constant. Respiration and viability of irradiated cells were affected not at all by the presence of superoxide dismutase and only slightly by the presence of catalase. Metal ions such as Mn 2+ and Fe 2+ , inducers of superoxide dismutase, had no effect on respiration and viability. When irradiated cells were incubated under N 2 for 90 min, the respiration, growth, and viability time-course responses were the same as for cells not exposed to anaerobiosis. We conclude that superoxide anions generated at the time of irradiation play no part in cessation of respiration and cell death and that inadequate aeration or anaerobiosis delays the ultraviolet light-induced synthesis of proteins responsible for the irreversible cessation of respiration

  10. Stress response of Escherichia coli induced by surface streamer discharge in humid air

    International Nuclear Information System (INIS)

    Doležalová, Eva; Prukner, Václav; Lukeš, Petr; Šimek, Milan

    2016-01-01

    Inactivation of Escherichia coli by means of surface streamer discharge has been investigated to obtain new insights into the key mechanisms involved, with a particular emphasis placed on the microbial response to plasma-induced stress. The surface streamer discharge was produced in coplanar dielectric barrier discharge electrode geometry, and was driven by an amplitude-modulated ac high voltage in humid synthetic air at atmospheric pressure. The response to plasma-induced stress was evaluated by using conventional cultivation, sublethal injury and resazurin assay and the LIVE/DEAD ® BacLight ™ Bacterial Viability kit. Compared to conventional cultivation, the LIVE/DEAD ® test labels bacteria with damaged membranes, while resazurin assay tracks their metabolic activity. Our results clearly demonstrate that the treated bacteria partly lost their ability to grow properly, i.e. they became injured and culturable, or even viable but nonculturable (VBNC). The ability to develop colonies could have been lost due to damage of the bacterial membrane. Damage of the membranes was mainly caused by the lipid peroxidation, evidencing the key role of oxygen reactive species, in particular ozone. We conclude that the conventional cultivation method overestimates the decontamination efficiency of various plasma sources, and must therefore be complemented by alternative techniques capable of resolving viable but nonculturable bacteria. (paper)

  11. Genetic toxicology of metal compounds. II. Enhancement of ultraviolet light-induced mutagenesis in Escherichia coli WP2

    International Nuclear Information System (INIS)

    Rossman, T.G.; Molina, M.

    1986-01-01

    Salts of metals which are carcinogenic, noncarcinogenic, or of unknown carcinogenicity were assayed for their abilities to modulate ultraviolet (UV)-induced mutagenesis in Escherichia coli WP2. In addition to the previously reported comutagenic effect of arsenite, salts of three other compounds were found to enhance UV mutagenesis. CuCl 2 , MnCl 2 (and a small effect by KMnO 4 ), and NaMoO 4 acted as comutagens in E coli WP2, which has wild-type DNA repair capability, but were much less comutagenic in the repair deficient strain WP2/sub s/ (uvrA). The survival of irradiated or unirradiated cells was not affected by these compounds. No effects on UV mutagenesis were seen for 16 other metal compounds. We suggest that the comutagenic effects might occur either via metal-induced decreases in the fidelity of repair replication or via metal-induced depurination

  12. Detection of ctx-M gene in ESBL-producing E. coli strains isolated from urinary tract infection in Semnan, Iran.

    Science.gov (United States)

    Tabar, Mahbobeh Mohammad; Mirkalantari, Shiva; Amoli, Rabeeh Izadi

    2016-07-01

    The incidence of urinary tract infections caused by Extended-Spectrum Beta Lactamase (ESBL) producing Escherichia coli (E. coli) strains due to long term and overuse of broad-spectrum cephalosporine is on the rise. CTX beta-lactamase type, a broad-spectrum beta-lactamase, has been expanding in many countries. The ctx gene is harbored on a plasmid that is spread between Enterobacteriaceae family, especially in E. coli. The aim of this study was to determine the pattern of antimicrobial resistance and investigate the prevalent ESBL phenotype and the ctx-M gene in E. coli isolated from patients with urinary tract infections (UTI) in Semnan. A cross sectional study was performed on 109 strains of E. coli isolated from the urine culture of patient suffering from a UTI referred to Shafa hospital (Semnan, Iran) during March-July 2015. Antimicrobial susceptibility testing was applied and the prevalence of the ESBL phenotype was confirmed using combination disk. PCR methods were completed for amplification of the bla ctx gene. Data were analyzed using SPSS version 18 software. One hundred ninety samples (4.16%) were identified as E. coli. Twenty one (26.6%) of E. coli were ESBL positive and 73.4% were ESBL negative. There was 100% susceptibility to imipeneme. Twenty (68.97%) out of 29 isolates were positive for the ctx-M gene, as detected by PCR. In urinary tract infections, antibiotic treatment was experimental and detailed information regarding the sensitivity of bacteria in the area can be useful to achieve the best treatment.

  13. X-ray-induced mutations in Escherichia coli K-12 strains with altered DNA polymerase I activities

    International Nuclear Information System (INIS)

    Nagata, Yuki; Kawata, Masakado; Komura, Jun-ichiro; Ono, Tetsuya; Yamamoto, Kazuo

    2003-01-01

    Spectra of ionizing radiation mutagenesis were determined by sequencing X-ray-induced endogenous tonB gene mutations in Escherichia coli polA strains. We used two polA alleles, the polA1 mutation, defective for Klenow domain, and the polA107 mutation, defective for flap domain. We demonstrated that irradiation of 75 and 50 Gy X-rays could induce 3.8- and 2.6-fold more of tonB mutation in polA1 and polA107 strains, respectively, than spontaneous level. The radiation induced spectrum of 51 tonB mutations in polA1 and 51 in polA107 indicated that minus frameshift, A:T→T:A transversion and G:C→T:A transversion were the types of mutations increased. Previously, we have reported essentially the same X-ray-induced tonB mutation spectra in the wild-type strain. These results indicate that (1) X-rays can induce minus frameshift, A:T→T:A transversion and G:C→T:A transversion in E. coli and (2) presence or absence of polymerase I (PolI) of E. coli does not have any effects on the process of X-ray mutagenesis

  14. OBSERVATIONS ON CLINICAL TREATMENT TRIALS OF INDUCED ESCHERICHIA COLI DIARRHOEA IN BUFFALO NEONATAL CALVES

    Directory of Open Access Journals (Sweden)

    M. T. Javed, A. Khan, Abid Hussain and Babar Niaz

    2000-01-01

    Full Text Available The study was conducted on 24 calves of one week-age, randomly divided into four groups, of six calves each. First three groups were experimentally infected with E. coli and given treatment in various combinations, while group four was taken as uninfected untreated control. Results obtained on different parameters were, green to yellow-white diarrhoea with variable consistency from watery to semisolid. Generally in all groups during first two days, calves passed faeces around 6-10 times a day and this frequency lowered in about 2-4 days. During first 3-4 days of treatment, all calves appeared weak, dull, depressed with cold skin and wetness of the muzzle, while oral mucosa was pale and eyes were sunken. Overall mean respiration rate of treatment groups was slower (P<0.05 than control group. However, pulse rate showed no difference between treatment and control group. Overall mean rectal temperature was lower (P<0.05 in calves treated with antibiotic alone and with antibiotic + electrolytes, while body weight was higher (P<0.05 in calves treated with antibiotic but was lower along with creatinine (P<0.05 in calves treated with antibiotic + electrolytes and those treated with electrolytes alone.

  15. Repeated Treatments with Chitosan in Combination with Antibiotics Completely Eradicate Uropathogenic Escherichia coli From Infected Mouse Urinary Bladders.

    Science.gov (United States)

    Erman, Andreja; Hergouth, Veronika Križan; Blango, Matthew G; Kos, Mojca Kerec; Mulvey, Matthew A; Veranic, Peter

    2017-08-01

    Uropathogenic Escherichia coli (UPEC), the primary causative agents of urinary tract infections, colonize and invade the epithelial cells of the bladder urothelium. Infection of immature urothelial cells can result in the formation of persistent intracellular reservoirs that are refractory to antibiotic treatments. Previously, we defined a novel therapeutic strategy that used the bladder cell exfoliant chitosan to deplete UPEC reservoirs. However, although a single treatment of chitosan followed by ciprofloxacin administration had a marked effect on reducing UPEC titers within the bladder, this treatment failed to prevent relapsing bacteriuria. We show here that repeated use of chitosan in conjunction with the antibiotic ciprofloxacin completely eradicates UPEC from the urinary tract and prevents the development of relapsing bouts of bacteriuria. In addition, microscopy revealed rapid restoration of bladder integrity following chitosan treatment, indicating that chitosan can be used to effectively combat recalcitrant bladder infections without causing lasting harm to the urothelium. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

  16. WGS-based surveillance of third-generation cephalosporin-resistant Escherichia coli from bloodstream infections in Denmark

    DEFF Research Database (Denmark)

    Roer, Louise; Hansen, Frank; Thomsen, Martin Christen Frølund

    2017-01-01

    clone, here observed for the first time in Denmark. Additionally, the analysis revealed three individual cases with possible persistence of closely related clones collected more than 13 months apart. Continuous WGS-based national surveillance of 3GC-R Ec , in combination with more detailed......-genome sequenced and characterized by using the batch uploader from the Center for Genomic Epidemiology (CGE) and automatically analysed using the CGE tools according to resistance profile, MLST, serotype and fimH subtype. Additionally, the phylogenetic relationship of the isolates was analysed by SNP analysis......To evaluate a genome-based surveillance of all Danish third-generation cephalosporin-resistant Escherichia coli (3GC-R Ec ) from bloodstream infections between 2014 and 2015, focusing on horizontally transferable resistance mechanisms. A collection of 552 3GC-R Ec isolates were whole...

  17. Small RNA-Seq analysis reveals microRNA-regulation of the Imd pathway during Escherichia coli infection in Drosophila.

    Science.gov (United States)

    Li, Shengjie; Shen, Li; Sun, Lianjie; Xu, Jiao; Jin, Ping; Chen, Liming; Ma, Fei

    2017-05-01

    Drosophila have served as a model for research on innate immunity for decades. However, knowledge of the post-transcriptional regulation of immune gene expression by microRNAs (miRNAs) remains rudimentary. In the present study, using small RNA-seq and bioinformatics analysis, we identified 67 differentially expressed miRNAs in Drosophila infected with Escherichia coli compared to injured flies at three time-points. Furthermore, we found that 21 of these miRNAs were potentially involved in the regulation of Imd pathway-related genes. Strikingly, based on UAS-miRNAs line screening and Dual-luciferase assay, we identified that miR-9a and miR-981 could both negatively regulate Drosophila antibacterial defenses and decrease the level of the antibacterial peptide, Diptericin. Taken together, these data support the involvement of miRNAs in the regulation of the Drosophila Imd pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Antimicrobial susceptibility, risk factors and prevalence of bla cefotaximase, temoneira, and sulfhydryl variable genes among Escherichia coli in community-acquired pediatric urinary tract infection

    Directory of Open Access Journals (Sweden)

    Kallyadan V Nisha

    2017-01-01

    Conclusion: ESBL-producing E. coli from community-acquired pediatric UTI carries more than one type of beta-lactamase coding genes correlating their increased antibiotic resistance. Aggressive infection control policy, routine screening for detecting ESBL isolates in clinical samples, and antimicrobial stewardship are the keys to prevent their dissemination in community settings.

  19. Local and systemic occurrences of HMGB1 in gnotobiotic piglets infected with E. coli O55 are related to bacterial translocation and inflammatory cytokines

    Czech Academy of Sciences Publication Activity Database

    Šplíchalová, Alla; Šplíchal, Igor

    2012-01-01

    Roč. 60, č. 3 (2012), s. 597-600 ISSN 1043-4666 R&D Projects: GA ČR GA524/09/0365 Institutional support: RVO:61388971 Keywords : HMGB1 * Enteric infection * E. coli Subject RIV: EC - Immunology Impact factor: 2.518, year: 2012

  20. Draft Genome Sequences of Three Escherichia coli Strains with Different In Vivo Pathogenicities in an Avian (Ascending) Infection Model of the Oviduct.

    Science.gov (United States)

    Olsen, Rikke Heidemann; Thøfner, Ida Cecilie Naundrup; Pors, Susanne Elisabeth; Christensen, Henrik; Bisgaard, Magne; Christensen, Jens Peter

    2015-05-07

    Here, we present three draft genome sequences of Escherichia coli strains that experimentally were proven to possess low (strain D2-2), intermediate (Chronic_salp), or high virulence (Cp6salp3) in an avian (ascending) infection model of the oviduct. Copyright © 2015 Olsen et al.

  1. Genotypic Characterization of Streptococcus infantarius subsp. coli Isolates from Sea Otters with Infective Endocarditis and/or Septicemia and from Environmental Mussel Samples

    Science.gov (United States)

    Counihan-Edgar, Katrina L.; Gill, Verena A.; Doroff, Angela M.; Burek, Kathleen A.; Miller, Woutrina A.; Shewmaker, Patricia L.; Jang, Spencer; Goertz, Caroline E. C.; Tuomi, Pamela A.; Miller, Melissa A.; Jessup, David A.

    2012-01-01

    Pulsed-field gel electrophoresis (PFGE) was used to type 128 Streptococcus infantarius subsp. coli isolates from sea otters and mussels. Six SmaI PFGE groups were detected, with one predominant group representing 57% of the isolates collected over a wide geographic region. Several sea otter and mussel isolates were highly related, suggesting that an environmental infection source is possible. PMID:23052307

  2. Infective complications in patients after transrectal ultrasound-guided prostate biopsy and the role of ciprofloxacin resistant Escherichia coli colonization in rectal flora.

    Science.gov (United States)

    Hamarat, Mustafa Bilal; Tarhan, Fatih; Horuz, Rahim; Öcal, Gülfem Akengin; Demirkol, Mehmet Kutlu; Kafkaslı, Alper; Yazıcı, Özgür

    2017-06-01

    In the present study, we aimed to invastigate the ciprofloxacin resistance in rectal flora of the patients undergoing prostate biopsy in our department. Additionally, the possible effects of the presence of ciprofloxacin resistant bacteria in faecal flora on the risk of infective complications after the procedure as well as the effect of antibiotic prophylaxis on such infectious complications have been evaluated. A total of 142 patients undergoing transrectal ultrasound-guided prostate biopsy were included into the study program. Rectal swab samples were taken from all patients prior to biopsy. The presence of complications have been evaluated after a week following the biopsy procedure. Patients with fever were also evaluated. The possible correlation between the presence of ciprofloxacin-resistant bacteria in faecal flora and the risk of urinary tract infection development and the other complications were evaluated. E. coli bacteria were present in all cultures of rectal swab samples obtained from 142 patients prior to prostate biopsy. Of all these patients, while ciprofloxacin-resistant E. coli (CR E. coli ) grew in 76 (53.5%) patients; ciprofloxacin susceptible E. coli (CS E. coli ) was obtained in 66 (46.5%) patients. In 16 patients (11.3%), infectious complications were observed. While the infective complications were present in the 14.5% of patients with CR E. coli ; they were present in the 7.6% of patients with CS E. coli (p=0.295). High fever was observed in nine patients (6.3%). Of these nine patients, although six had CR E. coli growth as detected during culture sensitivity tests; three had CS E. coli growth in their rectal swab culture tests. Sepsis was observed in three (2.1%) of these patients with high fever. Ciprofloxacin-resistant E. coli grew in all of the rectal swab cultures obtained from these patients with sepsis. In the light of our findings we may say that, it will be appropriate to reconsider the ciprofloxacin prophylaxis and prefer to use

  3. Involvement of UV-inducible repair in pyrimidine dimer excision in Escherichia coli

    International Nuclear Information System (INIS)

    Masek, F.; Sedliakova, M.

    1978-01-01

    The influence of UV radiation on pyrimidine dimer excision in the cells of three excision-proficient E.coli strains was studied. For this purpose cells were irradiated with a first fluence of 300 ergs/mm 2 and at different time intervals with a second fluence of 500 ergs/mm 2 . After the second fluence dimer excision was found to be partly inhibited in E.coli B/r Hcr + and E.coli 15 555-7, but not in E.coli K12 SR20. (author)

  4. Involvement of UV-inducible repair in pyrimidine dimer excision in Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Masek, F; Sedliakova, M [Slovenska Akademia Vied, Bratislava (Czechoslovakia)

    1978-11-15

    The influence of UV radiation on pyrimidine dimer excision in the cells of three excision-proficient E.coli strains was studied. For this purpose cells were irradiated with a first fluence of 300 ergs/mm/sup 2/ and at different time intervals with a second fluence of 500 ergs/mm/sup 2/. After the second fluence dimer excision was found to be partly inhibited in E.coli B/r Hcr/sup +/ and E.coli 15 555-7, but not in E.coli K12 SR20.

  5. Comparison of clinical and immunological findings in gnotobiotic piglets infected with Escherichia coli O104:H4 outbreak strain and EHEC O157:H7.

    Science.gov (United States)

    Wöchtl, Bettina; Gunzer, Florian; Gerner, Wilhelm; Gasse, Hagen; Koch, Michaela; Bagó, Zoltán; Ganter, Martin; Weissenböck, Herbert; Dinhopl, Nora; Coldewey, Sina M; von Altrock, Alexandra; Waldmann, Karl-Heinz; Saalmüller, Armin; Zimmermann, Kurt; Steinmann, Jörg; Kehrmann, Jan; Klein-Hitpass, Ludger; Blom, Jochen; Ehricht, Ralf; Engelmann, Ines; Hennig-Pauka, Isabel

    2017-01-01

    Shiga toxin (Stx) producing Escherichia coli ( E. coli ) (STEC) is the most frequent cause of diarrhoea-positive haemolytic uraemic syndrome (D + HUS) in humans. In 2011, a huge outbreak with an STEC O104:H4 strain in Germany highlighted the limited possibilities for causative treatment of this syndrome. The responsible STEC strain was found to combine Stx production with adherence mechanisms normally found in enteroaggregative E. coli (EAEC). Pathotypes of E. coli evolve and can exhibit different adhesion mechanisms. It has been shown previously that neonatal gnotobiotic piglets are susceptible for infection with STEC, such as STEC O157:H7 as well as for EAEC, which are considered to be the phylogenetic origin of E. coli O104:H4. This study was designed to characterise the host response to infection with the STEC O104:H4 outbreak strain in comparison to an STEC O157:H7 isolate by evaluating clinical parameters (scoring) and markers of organ dysfunction (biochemistry), as well as immunological (flow cytometry, assessment of cytokines/chemokines and acute phase proteins) and histological alterations (light- and electron microscopy) in a gnotobiotic piglet model of haemolytic uraemic syndrome. We observed severe clinical symptoms, such as diarrhoea, dehydration and neurological disorders as well as attaching-and-effacing lesions (A/E) in the colon in STEC O157:H7 infected piglets. In contrast, STEC O104:H4 challenged animals exhibited only mild clinical symptoms including diarrhoea and dehydration and HUS-specific/severe histopathological, haematological and biochemical alterations were only inconsistently presented by individual piglets. A specific adherence phenotype of STEC O104:H4 could not be observed. Flow cytometric analyses of lymphocytes derived from infected animals revealed an increase of natural killer cells (NK cells) during the course of infection revealing a potential role of this subset in the anti-bacterial activity in STEC disease. Unexpectedly, E

  6. Lipoxin A4 and platelet activating factor are involved in E. coli or LPS-induced lung inflammation in CFTR-deficient mice.

    Directory of Open Access Journals (Sweden)

    Haiya Wu

    Full Text Available CFTR (cystic fibrosis transmembrane conductance regulator is expressed by both neutrophils and platelets. Lack of functional CFTR could lead to severe lung infection and inflammation. Here, we found that mutation of CFTR (F508del or inhibition of CFTR in mice led to more severe thrombocytopenia, alveolar neutrocytosis and bacteriosis, and lower lipoxin A4/MIP-2 (macrophage inhibitory protein-2 or lipoxin A4/neutrophil ratios in the BAL (bronchoalveolar lavage during acute E. coli pneumonia. In vitro, inhibition of CFTR promotes MIP-2 production in LPS-stimulated neutrophils; however, lipoxin A4 could dose-dependently suppress this effect. In LPS-induced acute lung inflammation, blockade of PSGL-1 (P-selectin glycoprotein ligand-1 or P-selectin, antagonism of PAF by WEB2086, or correction of mutated CFTR trafficking by KM11060 could significantly increase plasma lipoxin A4 levels in F508del relevant to wildtype mice. Concurrently, F508del mice had higher plasma platelet activating factor (PAF levels and PAF-AH activity compared to wildtype under LPS challenge. Inhibiting hydrolysis of PAF by a specific PAF-AH (PAF-acetylhydrolase inhibitor, MAFP, could worsen LPS-induced lung inflammation in F508del mice compared to vehicle treated F508del group. Particularly, depletion of platelets in F508del mice could significantly decrease plasma lipoxin A4 and PAF-AH activity and deteriorate LPS-induced lung inflammation compared to control F508del mice. Taken together, lipoxin A4 and PAF are involved in E. coli or LPS-induced lung inflammation in CFTR-deficient mice, suggesting that lipoxin A4 and PAF might be therapeutic targets for ameliorating CFTR-deficiency deteriorated lung inflammation.

  7. The in vitro synthesis of β-galactosidase induced in a subcellular structure of Escherichia coli (1961)

    International Nuclear Information System (INIS)

    Nisman, B.; Kayser, A.; Demailly, J.; Genin, C.

    1961-01-01

    Isopropyl-thio-galactoside (IPTG), an inducer of 3-galactosidase, makes it possible to synthesise this enzyme in vitro with the subcellular structure (P 1 ). The enzyme is isolated from the bacteria Escherichia coli K 12 which are inductive but not induced. The incorporation of radioactive amino-acids, which is stimulated by the presence of an inducer, was studied during the course of the enzyme synthesis. Saccharose suppresses the induction of β-galactosidase. The presence of a specific inhibitor in the structure studied is considered. (authors) [fr

  8. 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 econo...

  9. North Idaho E. coli Infections Linked to Raw Clover Sprouts > Idaho

    Science.gov (United States)

    About Establishing Legal Fatherhood Genetic Testing Ending Services Fees for Services Child Support and Children's Special Health Program Genetic/Metabolic Services Genetic Condition Information Health Care Healthcare Associated Infections Antibiotic Resistance Epidemiology Idaho Disease Bulletin Data and

  10. Treatment of in vitro enterohemorrhagic Escherichia coli infection using phage and probiotics.

    Science.gov (United States)

    Dini, C; Bolla, P A; de Urraza, P J

    2016-07-01

    To assay the combination of phage and probiotics against EHEC in vitro on infected Hep-2 cells. Phage and probiotics treatments on EHEC O157:H7-infected Hep-2 cells were assayed individually or combined. The effect of freeze-drying on phage and probiotic antimicrobial activity was also studied. While treatment with phage alone increased cell detachment caused by EHEC infection, the treatments with MM alone or in combination with phage proved to effectively diminish cell damage caused by EHEC infection. Combined treatment showed a decrease in apoptotic cell count of 57·3% and a reduction in EHEC adhesion to cell monolayer of 1·2 log CFU. The simultaneous use of phage and probiotics showed no antagonistic effect, and freeze-drying did not affect their antipathogenic activity. The combination of phage and probiotics has great potential for reducing the number of pathogens adhered to epithelial cells during EHEC O157:H7 infection and attenuating the cytotoxic effect derived from it. Further in vivo assays are needed for assessing the actual effectiveness of the treatment. This study presents a freeze-dried formulation of phage and probiotics capable of controlling EHEC infections and reducing epithelial cell damage in vitro. © 2016 The Society for Applied Microbiology.

  11. Photoreactivation reverses ultraviolet radition induced premutagenic lesions leading to frameshift mutations in Escherichia coli

    International Nuclear Information System (INIS)

    Yamamoto, Kazuo

    1985-01-01

    The effect of photoreactivation of the ultraviolet radiation induced reversion of a trpE9777 frameshift mutation was studied in a uvr A6 derivative of Escherichia coli K12. Two different photoreactivation treatments were used, one providing a single flash of photoreactivating light and another providing 10 min of light from fluorescent lamps. The reversion frequency of the trpE9777 frameshift mutation was strongly reduced when subsueqently exposed to visible light. The dose modification factor (the ratio of equally effective doses), for cells challenged with single-flash photoreactivation, for survival and induction of reversion to Trp + was 3.6 and 3.4, respectively. UV induction of RecA protein synthesis was not reversed by a single flash of photoreactivation. The dose modification factor for 10 min of fluorescent lamp photoreactivation for survival and for induction of reversion to Trp + was 6.5 and 6.3, respectively. The dose modification factor for 10 min of photoreactivation for induction of RecA protein was 1.7-2.5. Photoreactivation decreased the reversion of trpE9777 and increased survival to the same extent. We concluded that cyclobutyl pyrimidine dimers are the premutagenic lesions of UV mutagenesis of the trpE9777 allele in a uvr A6 background. (orig.)

  12. L-Glycine Alleviates Furfural-Induced Growth Inhibition during Isobutanol Production in Escherichia coli.

    Science.gov (United States)

    Song, Hun-Suk; Jeon, Jong-Min; Choi, Yong Keun; Kim, Jun-Young; Kim, Wooseong; Yoon, Jeong-Jun; Park, Kyungmoon; Ahn, Jungoh; Lee, Hongweon; Yang, Yung-Hun

    2017-12-28

    Lignocellulose is now a promising raw material for biofuel production. However, the lignin complex and crystalline cellulose require pretreatment steps for breakdown of the crystalline structure of cellulose for the generation of fermentable sugars. Moreover, several fermentation inhibitors are generated with sugar compounds, majorly furfural. The mitigation of these inhibitors is required for the further fermentation steps to proceed. Amino acids were investigated on furfural-induced growth inhibition in E. coli producing isobutanol. Glycine and serine were the most effective compounds against furfural. In minimal media, glycine conferred tolerance against furfural. From the IC₅₀ value for inhibitors in the production media, only glycine could alleviate growth arrest for furfural, where 6 mM glycine addition led to a slight increase in growth rate and isobutanol production from 2.6 to 2.8 g/l under furfural stress. Overexpression of glycine pathway genes did not lead to alleviation. However, addition of glycine to engineered strains blocked the growth arrest and increased the isobutanol production about 2.3-fold.

  13. Evaluation of Antibiotic Resistance and Detection of papC and papG genes in Escherichia coli Strains Isolated from Patients with Urinary Tract Infection

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    Mitra Alishah

    2016-11-01

    Full Text Available Abstract Background and Objectives: Escherichia coli is the most common etiologic factor of urinary tract infection, which its most important virulence factor is P fimbriae. Uropathogenic E. coli expresses various types of adhesins, such as pili adhesins (pyelonephritis-associated pili, Pap that mediates binding to the surface of epithelial cells of the urinary tract. This study aims to identify papC and papG genes and to evaluate antibiotic resistance level in the isolated E. coli samples. Methods: In this descriptive cross-sectional study, 50 samples were collected from patients with urinary tract infection and after isolation of bacteria and DNA extraction, antibiotic susceptibility tests was performed by disc diffusion method using related antibiotics. Presence of papG and papC genes (class I, II, and III was assessed by multiplex PCR method. Statistical data were analyzed using descriptive t-test. Results: The isolated E. coli samples were susceptible to amikacin (100% and cefepime (72% and resistant to ampicillin (100% and nitrofurantoin (94%. Eighteen samples (32.7% had papG gene, of which 17 (30.9% samples had papGII gene and 1 sample (1.8% had papGIII gene; papGI gene was not detected in any of the samples. Conclusion: The results of the present study showed that papC and papGI genes are the most common Pap fimbriae adhesion-encoding genes in E. coli isolated from urinary tract infection. The difference between the results of this study with those of other studies is due to geographic diversity. Keywords: Escherichia coli; Adhesion pap, Disk diffusion antimicrobial tests; Multiplex polymerase chain reaction.

  14. Rhinovirus infection induces distinct transcriptome profiles in polarized human macrophages.

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    Rajput, Charu; Walsh, Megan P; Eder, Breanna N; Metitiri, Ediri E; Popova, Antonia P; Hershenson, Marc B

    2018-05-01

    Infections with rhinovirus (RV) cause asthma exacerbations. Recent studies suggest that macrophages play a role in asthmatic airway inflammation and the innate immune response to RV infection. Macrophages exhibit phenotypes based on surface markers and gene expression. We hypothesized that macrophage polarization state alters gene expression in response to RV infection. Cells were derived from human peripheral blood derived monocytes. M1 and M2 polarization was carried out by using IFN-γ and IL-4, respectively, and RNA was extracted for Affymetrix Human Gene ST2.1 exon arrays. Selected genes were validated by quantitative (q)PCR. Treatment of nonactivated (M0) macrophages with IFN-γ and IL-4 induced the expression of 252 and 153 distinct genes, respectively, including previously-identified M1 and M2 markers. RV infection of M0 macrophages induced upregulation of 232 genes; pathway analysis showed significant overrepresentation of genes involved in IFN-α/β signaling and cytokine signaling in the immune system. RV infection induced differential expression of 195 distinct genes in M1-like macrophages but only seven distinct genes in M2-like-polarized cells. In a secondary analysis, comparison between M0-, RV-infected, and M1-like-polarized, RV-infected macrophages revealed differential expression of 227 genes including those associated with asthma and its exacerbation. qPCR demonstrated increased expression of CCL8, CXCL10, TNFSF10, TNFSF18, IL6, NOD2, and GSDMD and reduced expression of VNN1, AGO1, and AGO2. Together, these data show that, in contrast to M2-like-polarized macrophages, gene expression of M1-like macrophages is highly regulated by RV.

  15. Release of Periplasmic Nucleotidase Induced by Human Antimicrobial Peptide in E. coli Causes Accumulation of the Immunomodulator Adenosine.

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    Andreia Bergamo Estrela

    Full Text Available Previous work by our group described that human β-defensin-2 induces accumulation of extracellular adenosine (Ado in E. coli cultures through a non-lytic mechanism causing severe plasmolysis. Here, we investigate the presence of AMP as a direct precursor and the involvement of a bacterial enzyme in the generation of extracellular Ado by treated bacteria. Following hBD-2 treatment, metabolites were quantified in the supernatants using targeted HPLC-MS/MS analysis. Microbial growth was monitored by optical density and cell viability was determined by colony forming units counts. Phosphatase activity was measured using chromogenic substrate pNPP. The results demonstrate that defensin-treated E. coli strain W releases AMP in the extracellular space, where it is converted to Ado by a bacterial soluble factor. An increase in phosphatase activity in the supernatant was observed after peptide treatment, similar to the effect of sucrose-induced osmotic stress, suggesting that the periplasmic 5'nucleotidase (5'-NT is released following the plasmolysis event triggered by the peptide. Ado accumulation was enhanced in the presence of Co2+ ion and inhibited by EDTA, further supporting the involvement of a metallo-phosphatase such as 5'-NT in extracellular AMP conversion into Ado. The comparative analysis of hBD-induced Ado accumulation in different E. coli strains and in Pseudomonas aeruginosa revealed that the response is not correlated to the peptide's effect on cell viability, but indicates it might be dependent on the subcellular distribution of the nucleotidase. Taken together, these data shed light on a yet undescribed mechanism of host-microbial interaction: a human antimicrobial peptide inducing selective release of a bacterial enzyme (E. coli 5'-NT, leading to the formation of a potent immunomodulator metabolite (Ado.

  16. Antibacterial efficacy of ethyl acetate fraction of Psidium guajava leaf aqueous extract on experimental Escherichia coli (O78) infection in chickens.

    Science.gov (United States)

    Geidam, Y A; Ambali, A G; Onyeyili, P A; Tijjani, M B; Gambo, H I; Gulani, I A

    2015-03-01

    This study was desingned to examine the efficacy of ethyl acetate fraction of aqueous extracted Psidium guajava leaves on chicks experimentally-infected with diarrheagenic strain of Escherichia coli O78. A total of 60 ISA brown male chicks were randomly divided into 6 Groups of ten chicks each in separate cages. Group A was not infected and not treated. Groups B, C and D were infected and treated with extracts at a dose of 25, 50 and 100 mg/kg respectively for 10 days. Group E was infected and treated with oxytetracycline while Group F was infected, but left untreated. Chicks from all groups were closely monitored for clinical signs, body weight change and fecal bacterial shedding load during the course of the experiment. Diarrhea, vents pasted with feces, drop in feed intake accompanied by slow weight gain and decreased activity was observed in infected untreated groups. Groups treated with graded doses of the extract experienced a dose-dependent decreased in severity of the clinical signs shown compared to the infected untreated group. Bacterial shedding load was found to be lower in groups treated with the extract and oxytetracycline than those without intervention. Ethyl acetate soluble fraction of leaf extract of Psidium guajava effectively controlled diarrhea and decreased the severity of other clinical signs caused by experimental E. coli infections in chicks.

  17. Prevention of pathogenic Escherichia coli infection in mice and stimulation of macrophage activation in rats by an oral administration of probiotic Lactobacillus casei I-5.

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    Ishida-Fujii, Keiko; Sato, Rieko; Goto, Shingo; Yang, Xiao-Ping; Kuboki, Hiroshi; Hirano, Shin-Ichi; Sato, Michikatsu

    2007-04-01

    Lactobacillus casei I-5 isolated from an alcohol fermentation broth enhanced immunity and prevented pathogenic infection as a probiotic. Mice fed with I-5 cells for 11 days prior to an intraperitoneal challenge with pathogenic Escherichia coli Juhl exhibited a high survival rate compared with the control group. Rats fed with I-5 cells for 10 days significantly increased the phagocytosis of peritoneal macrophages. In a cell culture system employing peritoneal macrophages from rats, the I-5 administration activated NF-kappaB stimulated by LPS. It also enhanced LPS-stimulated IL-12 and TNF-alpha production, but not IL-6 production. These results show that L. casei I-5 effectively prevented infection by pathogenic E. coli possibly through the activation of peritoneal macrophages. The strain would be useful to prevent pathogenic microbial infections in humans and farm animals.

  18. A probabilistic assessment of the contribution of wastewater-irrigated lettuce to Escherichia coli O157:H7 infection risk and disease burden in Kumasi, Ghana.

    Science.gov (United States)

    Seidu, Razak; Abubakari, Amina; Dennis, Isaac Amoah; Heistad, Arve; Stenstrom, Thor Axel; Larbi, John A; Abaidoo, Robert C

    2015-03-01

    Wastewater use for vegetable production is widespread across the cities of many developing countries. Studies on the microbial health risks associated with the practice have largely depended on faecal indicator organisms with potential underestimation or overestimation of the microbial health risks and disease burdens. This study assessed the Escherichia coli O157:H7 infection risk and diarrhoeal disease burden measured in disability-adjusted life years (DALYs) associated with the consumption of wastewater-irrigated lettuce in Kumasi, Ghana using data on E. coli O157:H7 in ready-to-harvest, wastewater-irrigated lettuce. Two exposure scenarios - best case and worst case - associated with a single consumption of wastewater-irrigated lettuce were assessed. The assessment revealed wastewater-irrigated lettuce is contributing to the transmission of E. coli O157:H7 in Kumasi, Ghana. The mean E. coli O157:H7 infection risk and DALYs in the wet and dry seasons, irrespective of the exposure scenario, were above the World Health Organization tolerable daily infection risk of 2.7 × 10⁻⁷ per person per day and 10⁻⁶ DALYs per person per year. It is recommended that legislation with clear monitoring indicators and penalties is implemented to ensure that farmers and food sellers fully implement risk mitigating measures.

  19. Deep sequencing-based transcriptome analysis of chicken spleen in response to avian pathogenic Escherichia coli (APEC infection.

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    Qinghua Nie

    Full Text Available Avian pathogenic Escherichia coli (APEC leads to economic losses in poultry production and is also a threat to human health. The goal of this study was to characterize the chicken spleen transcriptome and to identify candidate genes for response and resistance to APEC infection using Solexa sequencing. We obtained 14422935, 14104324, and 14954692 Solexa read pairs for non-challenged (NC, challenged-mild pathology (MD, and challenged-severe pathology (SV, respectively. A total of 148197 contigs and 98461 unigenes were assembled, of which 134949 contigs and 91890 unigenes match the chicken genome. In total, 12272 annotated unigenes take part in biological processes (11664, cellular components (11927, and molecular functions (11963. Summing three specific contrasts, 13650 significantly differentially expressed unigenes were found in NC Vs. MD (6844, NC Vs. SV (7764, and MD Vs. SV (2320. Some unigenes (e.g. CD148, CD45 and LCK were involved in crucial pathways, such as the T cell receptor (TCR signaling pathway and microbial metabolism in diverse environments. This study facilitates understanding of the genetic architecture of the chicken spleen transcriptome, and has identified candidate genes for host response to APEC infection.

  20. Alemtuzumab-induced elimination of HIV-1-infected immune cells.

    Science.gov (United States)

    Ruxrungtham, Kiat; Sirivichayakul, Sunee; Buranapraditkun, Supranee; Krause, Werner

    2016-01-01

    Currently, there is no drug known that is able to eradicate either HIV or HIV-infected host cells. The effectiveness of all available treatments is based on the prevention of viral replication. We investigated whether the monoclonal, CD52 receptor-targeting antibody, alemtuzumab, which is currently approved for the treatment of multiple sclerosis, is able to eliminate HIV-infected immune cells. In blood samples from healthy donors and from HIV-1-infected subjects who were either treatment-naïve or resistant to HAART, we studied whether the CD52 expression on T cells and their subsets (CD3, CD4, CD8), B cells (CD19), dendritic cells (CD123) and monocytes (CD11c) is retained in HIV-1 infection and whether alemtuzumab is able to eradicate infected cells, using four-colour flow cytometry. We found that CD52 expression on immune cells is retained in HIV-1 infection regardless of CD4 cell count, viral load and treatment status, and is amenable to alemtuzumab-induced depletion. For the first time it could be shown in vitro that HIV-1-infected immune cells can be eliminated by using the monoclonal antibody alemtuzumab.

  1. The new pLAI (lux regulon based auto-inducible expression system for recombinant protein production in Escherichia coli

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    Nocadello Salvatore

    2012-01-01

    Full Text Available Abstract Background After many years of intensive research, it is generally assumed that no universal expression system can exist for high-level production of a given recombinant protein. Among the different expression systems, the inducible systems are the most popular for their tight regulation. However, induction is in many cases less favorable due to the high cost and/or toxicity of inducers, incompatibilities with industrial scale-up or detrimental growth conditions. Expression systems using autoinduction (or self-induction prove to be extremely versatile allowing growth and induction of recombinant proteins without the need to monitor cell density or add inducer. Unfortunately, almost all the actual auto inducible expression systems need endogenous or induced metabolic changes during the growth to trigger induction, both frequently linked to detrimental condition to cell growth. In this context, we use a simple modular approach for a cell density-based genetic regulation in order to assemble an autoinducible recombinant protein expression system in E. coli. Result The newly designed pLAI expression system places the expression of recombinant proteins in Escherichia coli under control of the regulatory genes of the lux regulon of Vibrio fischeri's Quorum Sensing (QS system. The pLAI system allows a tight regulation of the recombinant gene allowing a negligible basal expression and expression only at high cell density. Sequence optimization of regulative genes of QS of V. fischeri for expression in E. coli upgraded the system to high level expression. Moreover, partition of regulative genes between the plasmid and the host genome and introduction of a molecular safety lock permitted tighter control of gene expression. Conclusion Coupling gene expression to cell density using cell-to-cell communication provides a promising approach for recombinant protein production. The system allows the control of expression of the target recombinant gene

  2. Carvacrol Induces Heat Shock Protein 60 and Inhibits Synthesis of Flagellin in Escherichia coli O157:H7▿

    Science.gov (United States)

    Burt, Sara A.; van der Zee, Ruurd; Koets, Ad P.; de Graaff, Anko M.; van Knapen, Frans; Gaastra, Wim; Haagsman, Henk P.; Veldhuizen, Edwin J. A.

    2007-01-01

    The essential oils of oregano and thyme are active against a number of food-borne pathogens, such as Escherichia coli O157:H7. Carvacrol is one of the major antibacterial components of these oils, and p-cymene is thought to be its precursor in the plant. The effects of carvacrol and p-cymene on protein synthesis in E. coli O157:H7 ATCC 43895 cells were investigated. Bacteria were grown overnight in Mueller-Hinton broth with a sublethal concentration of carvacrol or p-cymene, and their protein compositions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and confirmed by Western blotting. The presence of 1 mM carvacrol during overnight incubation caused E. coli O157:H7 to produce significant amounts of heat shock protein 60 (HSP60) (GroEL) (P < 0.05) and inhibited the synthesis of flagellin highly significantly (P < 0.001), causing cells to be aflagellate and therefore nonmotile. The amounts of HSP70 (DnaK) were not significantly affected. p-Cymene at 1 mM or 10 mM did not induce HSP60 or HSP70 in significant amounts and did not have a significant effect on flagellar synthesis. Neither carvacrol (0.3, 0.5, 0.8, or 1 mM) nor p-cymene (0.3, 0.5, or 0.8 mM) treatment of cells in the mid-exponential growth phase induced significant amounts of HSP60 or HSP70 within 3 h, although numerical increases of HSP60 were observed. Motility decreased with increasing concentrations of both compounds, but existing flagella were not shed. This study is the first to demonstrate that essential oil components induce HSP60 in bacteria and that overnight incubation with carvacrol prevents the development of flagella in E. coli O157:H7. PMID:17526792

  3. Plasmid-mediated AmpC beta-lactamase-producing Escherichia coli causing urinary tract infection in the Auckland community likely to be resistant to commonly prescribed antimicrobials.

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    Drinkovic, Dragana; Morris, Arthur J; Dyet, Kristin; Bakker, Sarah; Heffernan, Helen

    2015-03-13

    To estimate the prevalence and characterise plasmid-mediated AmpC beta-lactamase (PMACBL)- producing Escherichia coli in the Auckland community. All cefoxitin non-susceptible (NS) E. coli identified at the two Auckland community laboratories between 1 January and 31 August 2011 were referred to ESR for boronic acid double-disc synergy testing, to detect the production of AmpC beta-lactamase, and polymerase chain reaction (PCR) to identify the presence of PMACBL genes. PMACBL-producing isolates were typed using pulsed-field gel electrophoresis (PFGE), and PCR was used to determine their phylogenetic group and to identify multilocus sequence type (ST)131. Antimicrobial susceptibility testing and detection of extended-spectrum beta-lactamases (ESBLs) were performed according to the Clinical and Laboratory Standards Institute recommendations. 101 (51%) and 74 (37%) of 200 non-duplicate cefoxitin-NS E. coli were PMACBL producers or assumed hyper-producers of chromosomal AmpC beta-lactamase, respectively. The prevalence of PMACBL-producing E. coli was 0.4%. PMACBL-producing E. coli were significantly less susceptible to norfloxacin, trimethoprim and nitrofurantoin than E. coli that produced neither a PMACBL nor an ESBL. Very few (4%) PMACBL-producing E. coli co-produced an ESBL. Most (88%) of the PMACBL-producing isolates had a CMY-2-like PMACBL. The PMACBL-producing E. coli isolates were diverse based on their PFGE profiles, 44% belonged to phylogenetic group D, and only four were ST131. 100 of the 101 PMACBL-producing E. coli were cultured from urine, and were causing urinary tract infection (UTI) in the majority of patients. The median patient age was 56 years and most (94%) of the patients were women. A greater proportion of patients with community-acquired UTI caused by PMACBL-producing E. coli received a beta-lactam antimicrobial than patients with community-acquired UTI caused by other non-AmpC, non-ESBL-producing E. coli. Thirty-six (43%) patients with community

  4. Normal milk microbiome is reestablished following experimental infection with Escherichia coli independent of intramammary antibiotic treatment with a third-generation cephalosporin in bovines.

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    Ganda, Erika K; Gaeta, Natalia; Sipka, Anja; Pomeroy, Brianna; Oikonomou, Georgios; Schukken, Ynte H; Bicalho, Rodrigo C

    2017-07-12

    The use of antimicrobials in food animals and the emergence of antimicrobial resistance are global concerns. Ceftiofur is the only third-generation cephalosporin labeled for veterinary use in the USA, and it is the drug of choice in the majority of dairy farms for the treatment of mastitis. Here, we use next-generation sequencing to describe longitudinal changes that occur in the milk microbiome before, during, and after infection and treatment with ceftiofur. Twelve animals were intramammary challenged with Escherichia coli in one quarter and randomly allocated to receive intramammary treatment with ceftiofur (5d) or untreated controls. Serial samples were collected from -72 to 216 h relative to challenge from the challenged quarter, an ipsilateral quarter assigned to the same treatment group, and from a third quarter that did not undergo intervention. Infection with E. coli dramatically impacted microbial diversity. Ceftiofur significantly decreased LogCFUs but had no significant effect on the milk microbiome, rate of pathogen clearance, or somatic cell count. At the end of the study, the microbial profile of infected quarters was indistinguishable from pre-challenge samples in both treated and untreated animals. Intramammary infusion with ceftiofur did not alter the healthy milk (i.e., milk devoid of clots or serous appearance and collected from a mammary gland that shows no clinical signs of mastitis) microbiome. Our results indicate that the mammary gland harbors a resilient microbiome, capable of reestablishing itself after experimental infection with E. coli independent of antimicrobial treatment.

  5. Dental Infection of Porphyromonas gingivalis Induces Preterm Birth in Mice.

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    Min Ao

    Full Text Available Epidemiological studies have revealed a link between dental infection and preterm birth or low birth weight (PTB/LBW, however, the underlying mechanisms remain unclear. Progress in understanding the associated mechanisms has been limited in part by lack of an animal model for chronic infection-induced PTB/LBW, mimicking pregnancy under conditions of periodontitis. We aimed to establish a mouse model of chronic periodontitis in order to investigate the link between periodontitis and PTB/LBW.To establish chronic inflammation beginning with dental infection, we surgically opened mouse (female, 8 weeks old 1st molar pulp chambers and directly infected with w83 strain Porphyromonas gingivalis (P.g., a keystone periodontal pathogen. Mating was initiated at 6 wks post-infection, by which time dental granuloma tissue had developed and live P.g. was cultured from extracted tooth root, which serves as a persistent source of P.g. The gestational day (gd and birth weight were recorded during for P.g.-infected and control mice, and serum and placental tissues were collected at gd 15 to evaluate the systemic and local conditions during pregnancy.Dental infection with P.g. significantly increased circulating TNF-α (2.5-fold, IL-17 (2-fold, IL-6 (2-fold and IL-1β (2-fold. The P.g.-infected group delivered at gd 18.25 vs. gd 20.45 in the non-infected control (NC group (p < 0.01, and pups exhibited LBW compared to controls (p < 0.01. P.g. was localized to placental tissues by immunohistochemistry and PCR, and defects in placental tissues of P.g. infected mice included premature rupture of membrane, placental detachment, degenerative changes in trophoblasts and endothelial cells, including necrotic areas. P.g. infection caused significantly increased numbers of polymorphonuclear leukocytes (PMNLs and macrophages in placental tissues, associated with increased local expression of pro-inflammatory mediators including TNF-α and COX-2. Further placental tissue

  6. 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...

  7. Antimicrobial susceptibility and mechanisms of fosfomycin resistance in extended-spectrum β-lactamase-producing Escherichia coli strains from urinary tract infections in Wenzhou, China.

    Science.gov (United States)

    Bi, Wenzi; Li, Bin; Song, Jiangning; Hong, Youliang; Zhang, Xiaoxiao; Liu, Haiyang; Lu, Hong; Zhou, Tieli; Cao, Jianming

    2017-07-01

    Fosfomycin in combination with various antibiotics represents an excellent clinically efficacious regimen for the treatment of urinary tract infections (UTIs) caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. Underlying mechanisms of fosfomycin resistance remain largely uncharacterised. To investigate the antibacterial efficacy of fosfomycin against ESBL-producing E. coli, 356 non-repetitive ESBL-producing E. coli clinical isolates were collected from urine specimens from patients with UTI in Wenzhou, China, from January 2011 to December 2015. Antimicrobial sensitivity testing indicated that 6.7% (24/356) of the ESBL-producing E. coli strains were resistant to fosfomycin. The fosA3 gene encoding a fosfomycin-modifying enzyme was detected in 20 isolates by PCR and sequencing, alone or in combination with other ESBL determinants. Conjugation experiments and Southern blotting demonstrated that 70% (14/20) of the fosA3-positive isolates possessed transferable plasmids (ca. 54.2 kb) co-harbouring the ESBL resistance gene bla CTX-M and the fosfomycin resistance gene fosA3. Among the four fosfomycin-resistant fosA3-negative E. coli isolates, three contained amino acid substitutions (Ile28Asn and Phe30Leu in MurA and Leu297Phe in GlpT). The results indicate that presence of the fosA3 gene is the primary mechanism of fosfomycin resistance in ESBL-producing E. coli isolates in Wenzhou, China. In addition, a plasmid (ca. 54.2 kb) co-harbouring fosA3 and bla CTX-M genes is horizontally transferable. Furthermore, a low degree of homology in the fosfomycin-resistant E. coli was confirmed using multilocus sequence typing (MLST), suggesting that there is no obvious phenomenon of clonal dissemination. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  8. First-Line Antimicrobial Resistance Patterns of Escherichia coli in Children With Urinary Tract Infection in Emergency Department and Primary Care Clinics.

    Science.gov (United States)

    Ahmed, M Nadeem; Vannoy, Debby; Frederick, Ann; Chang, Sandy; Lawler, Elisabeth

    2016-01-01

    To identify risk factors for antibiotic resistance to Escherichia coli (E. coli) in children with urinary tract infections (UTIs) in emergency room and primary care clinics. This is a cross-sectional study of children 0 to 18 years of age reported to have E coli-positive UTIs whose medical and laboratory records were systematically reviewed. Compared with girls, boys were 2.29 times (confidence interval [CI] = 1.30-4.02) more likely to have E coli isolates resistant to ampicillin and 2 times more likely (CI = 1.13-3.62) to have isolates resistant to trimethoprim-sulfamethoxazole (TMP/SMX). Patients with genitourinary abnormalities were 1.57 times more likely to be resistant to ampicillin (CI = 1.03-2.41) and 1.86 times to TMP/SMX (CI = 1.18-2.94). Higher rates of ampicillin and TMP/SMX resistant urinary E coli isolates were observed among boys and children with a history of genitourinary abnormality. Age and recent antibiotic prescription are also potential risk factors for resistance. © The Author(s) 2015.

  9. Translational regulation of gene expression by an anaerobically induced small non-coding RNA in Escherichia coli

    DEFF Research Database (Denmark)

    Boysen, Anders; Møller-Jensen, Jakob; Kallipolitis, Birgitte H.

    2010-01-01

    Small non-coding RNAs (sRNA) have emerged as important elements of gene regulatory circuits. In enterobacteria such as Escherichia coli and Salmonella many of these sRNAs interact with the Hfq protein, an RNA chaperone similar to mammalian Sm-like proteins and act in the post...... that adaptation to anaerobic growth involves the action of a small regulatory RNA....... of at least one sRNA regulator. Here, we extend this view by the identification and characterization of a highly conserved, anaerobically induced small sRNA in E. coli, whose expression is strictly dependent on the anaerobic transcriptional fumarate and nitrate reductase regulator (FNR). The sRNA, named Fnr...

  10. Serotyping and Antimicrobial Susceptibility Pattern of Escherichia coli Isolates from Urinary Tract Infections in Pediatric Population in a Tertiary Care Hospital

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    Shweta Sharma

    2016-01-01

    Full Text Available Urinary tract infections (UTIs in pediatric population are associated with high morbidity and long term complications. In recent years, there is increased prevalence of Escherichia coli (E. coli strains producing extended spectrum β-lactamase, Amp C, and Metallo β-lactamase, making the clinical management even more difficult. This study was aimed to detect the serotypes and to determine antimicrobial susceptibility profile of E. coli isolates from urine samples of children <10 yrs old. A total of 75 pure E. coli strains isolated from patients with symptoms of UTI and colony count ≥105 organisms/mL were included in the study. Antibiotic sensitivity pattern showed maximum resistance to nalidixic acid (98.7%, followed by ampicillin (97.3%, amoxi-clavulanate (96%, and fluoroquinolones (92% while most of the isolates were found sensitive to piperacillin-tazobactam (13.3%, nitrofurantoin (5.3%, and meropenem (1.3%. 48% of the strains were ESBL producer (extended spectrum beta lactamase. 44% strains were typable withantisera used in our study and the most common serogroup was O6 (33.3% followed by O1 (15.1% and O15 (15.1%. To conclude, judicious use of antibiotics according to hospital antibiotic policy and infection control measures should be implemented to prevent spread of multidrug resistant organisms.

  11. Phylo-typing of clinical Escherichia coli isolates originating from bovine mastitis and canine pyometra and urinary tract infection by means of quadruplex PCR.

    Science.gov (United States)

    Müştak, Hamit Kaan; Günaydin, Elçin; Kaya, İnci Başak; Salar, Merve Özdal; Babacan, Orkun; Önat, Kaan; Ata, Zafer; Diker, Kadir Serdar

    2015-01-01

    Escherichia coli is one of the major causative agents of bovine mastitis worldwide, and is typically associated with acute, clinical mastitis. Besides this, E. coli strains which belong to the extra-intestinal pathogenic group are also the major cause of urinary tract infections and pyometra in dogs. In this study, it was aimed to investigate phylo-groups/subgroups in 155 E. coli isolates obtained from acute bovine mastitis, 43 from urinary tract infections of dogs and 20 from canine pyometra by a formerly described triplex PCR and recently described new quadruplex polymerase chain reaction (PCR) method. Group A1 (n = 118; 76%) and B1 (n = 71; 46%) were found to be the most prevalent groups by triplex and quadruplex PCR assays in mastitis isolates, respectively. Phylo-typing of 43 urinary tract isolates also revealed that most of the isolates belonged to A1 (n = 23; 54%) by triplex and B2 (n = 36; 84%) by quadruplex PCR assays. The isolates assigned as group A1 (n = 17; 85%) by triplex PCR could not be classified by quadruplex PCR in pyometra isolates. The results support the hypothesis that E. coli strains isolated from bovine mastitis cases are environmental. Also, groups C, E and F were identified as new phylo-groups for the first time in acute bovine mastitis cases. The comparison of triplex PCR with quadruplex PCR results revealed that most of the groups assigned in triplex PCR were altered by quadruplex PCR assay.

  12. Lactobacillus rhamnosus GR-1 Limits Escherichia coli-Induced Inflammatory Responses via Attenuating MyD88-Dependent and MyD88-Independent Pathway Activation in Bovine Endometrial Epithelial Cells.

    Science.gov (United States)

    Liu, Mingchao; Wu, Qiong; Wang, Mengling; Fu, Yunhe; Wang, Jiufeng

    2016-08-01

    Intrauterine Escherichia coli infection after calving reduces fertility and causes major economic losses in the dairy industry. We investigated the protective effect of the probiotic Lactobacillus rhamnosus GR-1 on E. coli-induced cell damage and inflammation in primary bovine endometrial epithelial cells (BEECs). L. rhamnosus GR-1 reduced ultrastructure alterations and the percentage of BEECs apoptosis after E. coli challenge. Increased messenger RNA (mRNA) expression of immune response indicators, including pattern recognition receptors (toll-like receptor [TLR]2, TLR4, nucleotide-binding oligomerization domain [NOD]1, and NOD2), inflammasome proteins (NOD-like receptor family member pyrin domain-containing protein 3, apoptosis-associated speck-like protein, and caspase-1), TLR4 downstream adaptor molecules (myeloid differentiation antigen 88 [MyD88], toll-like receptor adaptor molecule 2 [TICAM2]), nuclear transcription factor kB (NF-kB), and the inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-18, and interferon (IFN)-β, was observed following E. coli challenge. However, these increases were attenuated by L. rhamnosus GR-1 pretreatment. Our data indicate that L. rhamnosus GR-1 ameliorates the E. coli-induced disruption of cellular ultrastructure, subsequently reducing the percentage of BEECs apoptosis and limiting inflammatory responses, partly via attenuation of MyD88-dependent and MyD88-independent pathway activation. Certain probiotics could potentially prevent postpartum uterine diseases in dairy cows, ultimately reducing the use of antibiotics.

  13. Translesion DNA synthesis and mutation induced in a plasmid with a single adduct of the environmental contaminant 3-nitrobenzanthrone in SOS-induced Escherichia coli

    International Nuclear Information System (INIS)

    Kawanishi, M.; Kanno, T.; Yagi, T.; Enya-Takamura, T.; Fuchs, R.P.

    2003-01-01

    Full text: 3-Nitrobenzanthrone (NBA) is a powerfully mutagenic nitrated aromatic hydrocarbon found in diesel exhaust and in airborne particulate matters. NBA forms an unusual DNA adduct in vitro that has a C-C bond between the C-8 position of deoxyguanosine and the C-2 position of NBA. We previously found that this adduct is also present in the human cells treated with NBA, and induces mutations in supF shuttle vector system. In this study, we analyzed translesion DNA synthesis (TLS) over a single adduct in lacZ' gene in a plasmid in uvrAmutS Escherichia coli. The result showed that the adduct blocked DNA replication and an observed TLS frequency was 5.4% in non-SOS-induced E. coli. All progenies after the TLS had no mutation. On the other hand, TLS increased to 11.3%, and 4.8% of them had mostly G to T mutations in SOS-induced E. coli. These results suggest that this unusual adduct would be one of causes of lung cancer that is increasing in the urban areas polluted with diesel exhaust. It must be interesting to reveal which DNA polymerase is involved in this TLS

  14. Enterotoxigenic Escherichia coli Subclinical Infection in Pigs: Bacteriological and Genotypic Characterization and Antimicrobial Resistance Profiles.

    Science.gov (United States)

    Moredo, Fabiana A; Piñeyro, Pablo E; Márquez, Gabriela C; Sanz, Marcelo; Colello, Rocío; Etcheverría, Analía; Padola, Nora L; Quiroga, María A; Perfumo, Carlos J; Galli, Lucía; Leotta, Gerardo A

    2015-08-01

    Enterotoxigenic Escherichia coli (ETEC) is the major pathogen responsible for neonatal diarrhea, postweaning diarrhea, and edema disease in pigs. Although it can be harmless, ETEC is also present in the intestines of other animal species and humans, causing occasional diarrhea outbreaks. The evaluation of this pathogen's presence in food sources is becoming an increasingly important issue in human health. In order to determine the prevalence of ETEC in nondiarrheic pigs, 990 animals from 11 pig farms were sampled. Using end-time polymerase chain reaction (PCR), eltA, estI genes, or both, were detected in 150 (15.2%) animals. From the positive samples, 40 (26.6%) ETEC strains were isolated, showing 19 antibiotic-resistance patterns; 52.5% of these strains had multiple antibiotic resistances, and 17.5% carried the intI2 gene. The most prevalent genotypes were rfb(O157)/estII/aidA (32.5%) and estI/estII (25.0%). The estII gene was identified most frequently (97.5%), followed by estI (37.5%), astA (20.0%), and eltA (12.5%). The genes coding the fimbriae F5, F6, and F18 were detected in three single isolates. The aidA gene was detected in 20 ETEC strains associated with the estII gene. Among the isolated ETEC strains, stx(2e)/estI, stx(2e)/estI/estII, and stx(2e)/estI/estII/intI2 genotypes were identified. The ETEC belonged to 12 different serogroups; 37.5% of them belonged to serotype O157:H19. Isolates were grouped by enterobacterial repetitive intergenic consensus-PCR into 5 clusters with 100.0% similarity. In this study, we demonstrated that numerous ETEC genotypes cohabit and circulate in swine populations without clinical manifestation of neonatal diarrhea, postweaning diarrhea, or edema disease in different production stages. The information generated is important not only for diagnostic and epidemiological purposes, but also for understanding the dynamics and ecology of ETEC in pigs in different production stages that can be potentially transmitted to humans

  15. Characterization of Third-Generation Cephalosporin-Resistant Escherichia coli from Bloodstream Infections in Denmark

    DEFF Research Database (Denmark)

    Hansen, Frank; Olsen, Stefan S; Heltberg, Ole

    2014-01-01

    The aim of the study was to investigate the molecular epidemiology of 87 third-generation cephalosporin-resistant Escherichia coli (3GC-R Ec) from bloodstream infections in Denmark from 2009. Sixty-eight of the 87 isolates were extended-spectrum beta-lactamase (ESBL) producers, whereas 17 isolates...... featured AmpC mutations only (without a coexpressed ESBL enzyme) and 2 isolates were producing CMY-22. The majority (82%) of the ESBL-producing isolates in our study were CTX-M-15 producers and primarily belonged to phylogroup B2 (54.4%) or D (23.5%). Further, one of the two CMY-22-producing isolates...... belonged to B2, whereas only few of the other AmpCs isolates belonged to B2 and D. Pulsed-field gel electrophoresis revealed that both clonal and nonclonal spread of 3GC-R Ec occurred. ST131 was detected in 50% of ESBL-producing isolates. The remaining ESBL-producing isolates belonged to 17 other sequence...

  16. Distribution of virulence determinants among antimicrobial-resistant and antimicrobial-susceptible Escherichia coli implicated in urinary tract infections.

    Science.gov (United States)

    Stephenson, Sam; Brown, P D

    2016-01-01

    Uropathogenic Escherichia coli (UPEC) rely on the correlation of virulence expression with antimicrobial resistance to persist and cause severe urinary tract infections (UTIs). We assessed the virulence pattern and prevalence among UPEC strains susceptible and resistant to multiple antimicrobial classes. A total of 174 non-duplicate UPEC strains from patients with clinically significant UTIs were analysed for susceptibility to aminoglycoside, antifolate, cephalosporin, nitrofuran and quinolone antibiotics for the production of extended-spectrum β-lactamases and for the presence of six virulence determinants encoding adhesins (afimbrial, Type 1 fimbriae, P and S-fimbriae) and toxins (cytotoxic necrotising factor and haemolysin). Relatively high resistance rates to nalidixic acid, ciprofloxacin, cephalothin and trimethoprim-sulfamethoxazole (82%, 78%, 62% and 59%, respectively) were observed. Fourteen distinct patterns were identified for the virulence determinants such as afaBC, cnfI, fimH, hylA, papEF and sfaDE. The toxin gene, cnfI (75.3%), was the second most prevalent marker to the adhesin, fimH (97.1%). The significant association of sfaDE/hylA (P < 0.01) among antimicrobial resistant and susceptible strains was also observed notwithstanding an overall greater occurrence of virulence factors among the latter. This study provides a snapshot of UPEC complexity in Jamaica and highlights the significant clonal heterogeneity among strains. Such outcomes emphasise the need for evidence-based strategies in the effective management and control of UTIs.

  17. COMMON ORGANISMS AND ANTIBIOTIC SENSITIVITY OF E COLI IN URINARY TRACT INFECTION, IN A TERTIARY CARE TEACHING HOSPITAL, NORTHERN KERALA

    Directory of Open Access Journals (Sweden)

    Shanavas

    2015-11-01

    Full Text Available Urinary tract infection (UTI includes a spectrum of Asymptomatic Bacteruria (ABU, Cystitis, Prostitis and Pyelonephritis. Except in ABU, UTI is represented by symptomatic disease that warrants antimicrobial therapy. 1 Many of the studies have shown increasing antibiotic resistance to these agents. This study consists of a retrospective observational study of culture and sensitivity of 150 urinary samples, collected from patients who presented with symptoms of UTI, in a tertiary care teaching hospital, Northern Kerala, irrespective of their age and sex for a period of six months from June 2015 to November 2015. These results are then analyzed to find common organisms causing UTI in different age groups in either sex and their respective antibiotic resistance are noted. Out of 150 urinary samples 69.34% were sterile, while 30.66% were culture positive. Among the culture positive patients sex distribution was almost equal, with a slight female predominance, having a contribution of 54.35% females and 45.65% males. The most common organism was found to be E.coli, which contributed more than 50 per cent of total culture positivity (54.35%. Others include Staphylococci, Klebsiella Pnuemoniae, Proteus species, Pseudomonas, Enterococci, Candida Albicans etc. Collateral damage is an ecological adverse effect that resist the use of a highly efficacious drug to be considered as first line agent. Our study shows that drugs causing minimal collateral damages like Nitrofurantoin and Fosfomycin can be used as first line agent for treatment of UTI.

  18. 1H NMR spectroscopy-based metabolomics analysis for the diagnosis of symptomatic E. coli-associated urinary tract infection (UTI).

    Science.gov (United States)

    Lussu, Milena; Camboni, Tania; Piras, Cristina; Serra, Corrado; Del Carratore, Francesco; Griffin, Julian; Atzori, Luigi; Manzin, Aldo

    2017-09-21

    Urinary tract infection (UTI) is one of the most common diagnoses in girls and women, and to a lesser extent in boys and men younger than 50 years. Escherichia coli, followed by Klebsiella spp. and Proteus spp., cause 75-90% of all infections. Infection of the urinary tract is identified by growth of a significant number of a single species in the urine, in the presence of symptoms. Urinary culture is an accurate diagnostic method but takes several hours or days to be carried out. Metabolomics analysis aims to identify biomarkers that are capable of speeding up diagnosis. Urine samples from 51 patients with a prior diagnosis of Escherichia coli-associated UTI, from 21 patients with UTI caused by other pathogens (bacteria and fungi), and from 61 healthy controls were analyzed. The 1 H-NMR spectra were acquired and processed. Multivariate statistical models were applied and their performance was validated using permutation test and ROC curve. Orthogonal Partial Least Squares-discriminant Analysis (OPLS-DA) showed good separation (R 2 Y = 0.76, Q2=0.45, p UTI caused by Escherichia coli and healthy controls. Acetate and trimethylamine were identified as discriminant metabolites. The concentrations of both metabolites were calculated and used to build the ROC curves. The discriminant metabolites identified were also evaluated in urine samples from patients with other pathogens infections to test their specificity. Acetate and trimethylamine were identified as optimal candidates for biomarkers for UTI diagnosis. The conclusions support the possibility of a fast diagnostic test for Escherichia coli-associated UTI using acetate and trimethylamine concentrations.

  19. Efficacy of collagen silver-coated polyester and rifampin-soaked vascular grafts to resist infection from MRSA and Escherichia coli in a dog model.

    Science.gov (United States)

    Schneider, Fabrice; O'Connor, Stephen; Becquemin, Jean Pierre

    2008-11-01

    The primary objective of this study was to compare the efficacy of a collagen silver-coated polyester graft, InterGard, with a gelatin-sealed graft, Gelsoft, both soaked in rifampin, for resistance to direct bacterial contamination in an animal model. The second objective was to confirm the lack of inflammation from silver acetate. Vascular grafts, 6 mm in diameter, were implanted in the infrarenal aorta of 28 dogs. Intravenous cefamandole (20 mg/kg) was injected intraoperatively in all dogs. The dogs were divided into three groups. Group I included 12 dogs. Six dogs received silver grafts and six dogs received gelatin-sealed grafts, all soaked with rifampin. Grafts implanted in group I were directly infected with methicillin-resistant Staphylococcus aureus (MRSA). Group II included also six silver grafts and six gelatin-sealed grafts, all soaked with rifampin. Dogs of group II were directly infected with Escherichia coli. Group III comprised four dogs, which received gelatin unsealed grafts, directly infected with MRSA, the control group. All dogs were followed by regular clinical examination, including blood cultures. Grafts in groups I and III and in group II were harvested at 30 days and 10 days, respectively. Bacterial analyses were performed on the explanted grafts. Histology was performed on both the tissue samples and the anastomotic sites of the harvested grafts. In group I, no grafts were infected with MRSA, irrespective of graft type. In group II, no silver grafts were infected with E. coli, whereas one (16.6%) of six gelatin-sealed grafts was infected (p = 0.317). In group III, three (75%) of the four grafts were infected with MRSA. The infection rate in the silver grafts and the gelatin-sealed grafts soaked in rifampin in group I compared with the unsealed gelatin grafts in group III was statistically significantly different (p anastomoses in three (25%) gelsoft grafts of 12 in groups I and II. There were no clinical or biological signs of inflammation

  20. Bacterial feeding, Leishmania infection and distinct infection routes induce differential defensin expression in Lutzomyia longipalpis.

    Science.gov (United States)

    Telleria, Erich L; Sant'Anna, Maurício R Viana; Alkurbi, Mohammad O; Pitaluga, André N; Dillon, Rod J; Traub-Csekö, Yara M

    2013-01-11

    Phlebotomine insects harbor bacterial, viral and parasitic pathogens that can cause diseases of public health importance. Lutzomyia longipalpis is the main vector of visceral leishmaniasis in the New World. Insects can mount a powerful innate immune response to pathogens. Defensin peptides take part in this response and are known to be active against Gram-positive and Gram-negative bacteria, and some parasites. We studied the expression of a defensin gene from Lutzomyia longipalpis to understand its role in sand fly immune response. We identified, sequenced and evaluated the expression of a L. longipalpis defensin gene by semi-quantitative RT-PCR. The gene sequence was compared to other vectors defensins and expression was determined along developmental stages and after exposure of adult female L. longipalpis to bacteria and Leishmania. Phylogenetic analysis showed that the L. longipalpis defensin is closely related to a defensin from the Old World sand fly Phlebotomus duboscqi. Expression was high in late L4 larvae and pupae in comparison to early larval stages and newly emerged flies. Defensin expression was modulated by oral infection with bacteria. The Gram-positive Micrococcus luteus induced early high defensin expression, whilst the Gram-negative entomopathogenic Serratia marcescens induced a later response. Bacterial injection also induced defensin expression in adult insects. Female sand flies infected orally with Leishmania mexicana showed no significant difference in defensin expression compared to blood fed insects apart from a lower defensin expression 5 days post Leishmania infection. When Leishmania was introduced into the hemolymph by injection there was no induction of defensin expression until 72 h later. Our results suggest that L. longipalpis modulates defensin expression upon bacterial and Leishmania infection, with patterns of expression that are distinct among bacterial species and routes of infection.

  1. Antimicrobial susceptibility, risk factors and prevalence of bla cefotaximase, temoneira, and sulfhydryl variable genes among Escherichia coli in community-acquired pediatric urinary tract infection.

    Science.gov (United States)

    Nisha, Kallyadan V; Veena, Shetty A; Rathika, Shenoy D; Vijaya, Shenoy M; Avinash, Shetty K

    2017-01-01

    The emergence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli has become an important challenge among pediatric patients with community-acquired urinary tract infection (UTI). The aim of this study was to assess the antimicrobial susceptibility patterns, associated risk factors and to survey the frequency of bla cefotaximase (CTX-M), bla temoneira (TEM), and bla sulfhydryl variable (SHV) genotypes in ESBL-producing E. coli isolated from children with community-acquired UTI. This was a prospective study conducted from November 2012 to March 2016 in a tertiary care center. E. coli isolated in urine cultures from children aged ≤18 years was identified and confirmed for ESBL production. ESBL-positive strains were screened for ESBL encoding genes. Chi-square test and Fisher's exact test were used to compare the difference in antibiotic susceptibility with respect to ESBL positive and negative, and binary logistic regression was used to identify the risk factors associated with ESBL production. Among 523 E. coli isolates, 196 (37.5%) were ESBL positive, >90% were resistant to cephalosporins, and 56% were resistant to fluoroquinolones. Least resistance was observed for imipenem, netilmicin, and nitrofurantoin (2%, 8.6%, 15.3%). Association between ESBL production and drug resistance was significant for ceftazidime ( P antibiotics were the common risk factors. ESBL-producing E. coli from community-acquired pediatric UTI carries more than one type of beta-lactamase coding genes correlating their increased antibiotic resistance. Aggressive infection control policy, routine screening for detecting ESBL isolates in clinical samples, and antimicrobial stewardship are the keys to prevent their dissemination in community settings.

  2. Bistable behavior of the lac operon in E. coli when induced with a mixture of lactose and TMG

    Directory of Open Access Journals (Sweden)

    Orlando Díaz-Hernández

    2010-07-01

    Full Text Available In this work we investigate multistability in the lac operon of Escherichia coli when it is induced by a mixture of lactose and the non-metabolizable thiomethyl galactoside (TMG. In accordance with previously published experimental results and computer simulations, our simulations predict that: (1 when the system is induced by TMG, the system shows a discernible bistable behavior while, (2 when the system is induced by lactose, bistability does not disappear but excessively high concentrations of lactose would be required to observe it. Finally, our simulation results predict that when a mixture of lactose and TMG is used, the bistability region in the extracellular glucose concentration vs. extracellular lactose concentration parameter space changes in such a way that the model predictions regarding bistability could be tested experimentally. These experiments could help to solve a recent controversy regarding the existence of bistability in the lac operon under natural conditions.

  3. Bistable behavior of the lac operon in E. coli when induced with a mixture of lactose and TMG.

    Science.gov (United States)

    Díaz-Hernández, Orlando; Santillán, Moisés

    2010-01-01

    In this work we investigate multistability in the lac operon of Escherichia coli when it is induced by a mixture of lactose and the non-metabolizable thiomethyl galactoside (TMG). In accordance with previously published experimental results and computer simulations, our simulations predict that: (1) when the system is induced by TMG, the system shows a discernible bistable behavior while, (2) when the system is induced by lactose, bistability does not disappear but excessively high concentrations of lactose would be required to observe it. Finally, our simulation results predict that when a mixture of lactose and TMG is used, the bistability region in the extracellular glucose concentration vs. extracellular lactose concentration parameter space changes in such a way that the model predictions regarding bistability could be tested experimentally. These experiments could help to solve a recent controversy regarding the existence of bistability in the lac operon under natural conditions.

  4. Multiple pathways for SOS-induced mutagenesis in Escherichia coli: An overexpression of dinB/dinP results in strongly enhancing mutagenesis in the absence of any exogenous treatment to damage DNA

    Science.gov (United States)

    Kim, Su-Ryang; Maenhaut-Michel, Geneviéve; Yamada, Masami; Yamamoto, Yoshihiro; Matsui, Keiko; Sofuni, Toshio; Nohmi, Takehiko; Ohmori, Haruo

    1997-01-01

    dinP is an Escherichia coli gene recently identified at 5.5 min of the genetic map, whose product shows a similarity in amino acid sequence to the E. coli UmuC protein involved in DNA damage-induced mutagenesis. In this paper we show that the gene is identical to dinB, an SOS gene previously localized near the lac locus at 8 min, the function of which was shown to be required for mutagenesis of nonirradiated λ phage infecting UV-preirradiated bacterial cells (termed λUTM for λ untargeted mutagenesis). A newly constructed dinP null mutant exhibited the same defect for λUTM as observed previously with a dinB::Mu mutant, and the defect was complemented by plasmids carrying dinP as the only intact bacterial gene. Furthermore, merely increasing the dinP gene expression, without UV irradiation or any other DNA-damaging treatment, resulted in a strong enhancement of mutagenesis in F′lac plasmids; at most, 800-fold increase in the G6-to-G5 change. The enhanced mutagenesis did not depend on recA, uvrA, or umuDC. Thus, our results establish that E. coli has at least two distinct pathways for SOS-induced mutagenesis: one dependent on umuDC and the other on dinB/P. PMID:9391106

  5. Repair and gamma radiation-induced single- and double-strand breaks in DNA of Escherichia coli

    International Nuclear Information System (INIS)

    Petrov, S.I.

    1981-01-01

    Studies in the kinetics of repair of γ-radiation-induced single- and double-strand breaks in DNA of E. coli cells showed that double-strand DNA breaks are rejoined by the following two ways. The first way is conditioned by repair of single-strand breaks and represents the repair of ''oblique'' double-strand breaks in DNA, whereas the second way is conditioned by functioning of the recombination mechanisms and, to all appearance, represents the repair of ''direct'' double-strand breaks in DNA

  6. DNA replication in necessary for fixing induced mutations to streptomycin-resistance in UV-irradiated Escherichia coli cells

    Energy Technology Data Exchange (ETDEWEB)

    Dubinin, N P; Filippov, V D

    1986-01-01

    A suspension of E.coli cells has been subjected to UV radiation, then it has been incubated in the growth medium for 15 min. After that one of the portions was incubated with nalidixic acid (NA), and the other one without it in the presence of an antibiotic. Frequency of mutations depending on or irrespective of photoactivation, has been determined. Dependence of Str mutation fixing, induced by low UV radiation doses, on DNA synthesis is determined. Results indicate that both photoreactivation of mutations and its senstivity to mfd system are simultaneously lost.

  7. Risk factors for indigenous Campylobacter jejuni and Campylobacter coli infections in The Netherlands: a case-control study

    NARCIS (Netherlands)

    Doorduyn, Y.; Brandhof, van den W.E.; Duynhoven, van Y.T.H.P.; Breukink, B.J.; Wagenaar, J.A.; Pelt, van W.

    2010-01-01

    A case-control study comprising 1315 Campylobacter jejuni cases, 121 Campylobacter coli cases and 3409 frequency-matched controls was conducted in The Netherlands in 2002-2003. Risk factors for both C. jejuni and C. coli enteritis were consumption of undercooked meat and barbecued meat, ownership of

  8. Oxidative DNA damage is instrumental in hyperreplication stress-induced inviability of Escherichia coli

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Bjørn, Louise; Mendoza-Chamizo, Belén

    2014-01-01

    In Escherichia coli, an increase in the ATP bound form of the DnaA initiator protein results in hyperinitiation and inviability. Here, we show that such replication stress is tolerated during anaerobic growth. In hyperinitiating cells, a shift from anaerobic to aerobic growth resulted in appearance...

  9. [Prevalence and risk factors for extended-spectrum β-lactamase-producing Escherichia coli causing community-onset urinary tract infections in Colombia].

    Science.gov (United States)

    Blanco, Victor M; Maya, Juan J; Correa, Adriana; Perenguez, Marcela; Muñoz, Juan S; Motoa, Gabriel; Pallares, Christian J; Rosso, Fernando; Matta, Lorena; Celis, Yamile; Garzon, Martha; Villegas, María V

    2016-11-01

    Urinary tract infections (UTI) are common in the community. However, information of resistant isolates in this context is limited in Latin America. This study aims to determine the prevalence and risk factors associated with community-onset UTI (CO-UTI) caused by extended-spectrum β-lactamase (ESBL)-Producing Escherichia coli in Colombia. A case-control study was conducted between August and December of 2011 in three Colombian tertiary-care institutions. All patients who were admitted to the Emergency Department with a probable diagnosis of CO-UTI were invited to participate. All participating patients were asked for a urine sample. ESBL confirmatory test, antibiotic susceptibility, and molecular epidemiology were performed in these E.coli isolates (Real Time-PCR for bla genes, repetitive element palindromic PCR [rep-PCR], multilocus sequence typing [MLST] and virulence factors by PCR). Clinical and epidemiological information was recorded, and a statistical analysis was performed. Of the 2124 recruited patients, 629 had a positive urine culture, 431 of which grew E.coli; 54 were positive for ESBL, of which 29 were CTX-M-15. The majority of ESBL isolates were susceptible to ertapenem, phosphomycin and amikacin. Complicated UTI was strongly associated with ESBL-producing E.coli infections (OR=3.89; 95%CI: 1.10-13.89; P=.03). CTX-M-15-producing E.coli showed 10 different pulsotypes, 65% were PT1 or PT4, and corresponded to ST131. Most of these isolates had 8 out of the 9 analysed virulence factors. E.coli harbouring bla CTX-M-15 associated with ST131 is still frequent in Colombia. The presence of complicated CO-UTI increases the risk of ESBL-producing E.coli, and must be taken into account in order to provide an adequate empirical therapy. Copyright © 2015 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  10. Update of incidence and antimicrobial susceptibility trends of Escherichia coli and Klebsiella pneumoniae isolates from Chinese intra-abdominal infection patients.

    Science.gov (United States)

    Zhang, Hui; Yang, Qiwen; Liao, Kang; Ni, Yuxing; Yu, Yunsong; Hu, Bijie; Sun, Ziyong; Huang, Wenxiang; Wang, Yong; Wu, Anhua; Feng, Xianju; Luo, Yanping; Chu, Yunzhuo; Chen, Shulan; Cao, Bin; Su, Jianrong; Duan, Qiong; Zhang, Shufang; Shao, Haifeng; Kong, Haishen; Gui, Bingdong; Hu, Zhidong; Badal, Robert; Xu, Yingchun

    2017-12-18

    To evaluate in vitro susceptibilities of aerobic and facultative Gram-negative bacterial (GNB) isolates from intra-abdominal infections (IAIs) to 12 selected antimicrobials in Chinese hospitals from 2012 to 2014. Hospital acquired (HA) and community acquired (CA) IAIs were collected from 21 centers in 16 Chinese cities. Extended spectrum beta-lactamase (ESBL) status and antimicrobial susceptibilities were determined at a central laboratory using CLSI broth microdilution and interpretive standards. From all isolated strains the Enterobacteriaceae (81.1%) Escherichia coli accounted for 45.4% and Klebsiella pneumoniae for 20.1%, followed by Enterobacter cloacae (5.2%), Proteus mirabilis (2.1%), Citrobacter freundii (1.8%), Enterobacter aerogenes (1.8%), Klebsiella oxytoca (1.4%), Morganella morganii (1.2%), Serratia marcescens (0.7%), Citrobacter koseri (0.3%), Proteus vulgaris (0.3%) and others (1.0%). Non- Enterobacteriaceae (18.9%) included Pseudomonas aeruginosa (9.8%), Acinetobacter baumannii (6.7%), Stenotrophomonas maltophilia (0.9%), Aeromonas hydrophila (0.4%) and others (1.1%). ESBL-screen positive Escherichia coli isolates (ESBL+) showed a decreasing trend from 67.5% in 2012 to 58.9% in 2014 of all Escherichia coli isolates and the percentage of ESBL+ Klebsiella pneumoniae isolates also decreased from 2012 through 2014 (40.4% to 26.6%), which was due to reduced percentages of ESBL+ isolates in HA IAIs for both bacteria. The overall susceptibilities of all 5160 IAI isolates were 87.53% to amikacin (AMK), 78.12% to piperacillin-tazobactam (TZP) 81.41% to imipenem (IMP) and 73.12% to ertapenem (ETP). The susceptibility of ESBL-screen positive Escherichia coli strains was 96.77%-98.8% to IPM, 91.26%-93.16% to ETP, 89.48%-92.75% to AMK and 84.86%-89.34% to TZP, while ESBL-screen positive Klebsiella pneumoniae strains were 70.56%-80.15% susceptible to ETP, 80.0%-87.5% to IPM, 83.82%-87.06% to AMK and 63.53%-68.38% to TZP within the three year study

  11. Uropathogenic E. coli induce different immune response in testicular and peritoneal macrophages: implications for testicular immune privilege.

    Directory of Open Access Journals (Sweden)

    Sudhanshu Bhushan

    Full Text Available Infertility affects one in seven couples and ascending bacterial infections of the male genitourinary tract by Escherichia coli are an important cause of male factor infertility. Thus understanding mechanisms by which immunocompetent cells such as testicular macrophages (TM respond to infection and how bacterial pathogens manipulate defense pathways is of importance. Whole genome expression profiling of TM and peritoneal macrophages (PM infected with uropathogenic E. coli (UPEC revealed major differences in regulated genes. However, a multitude of genes implicated in calcium signaling pathways was a common feature which indicated a role of calcium-dependent nuclear factor of activated T cells (NFAT signaling. UPEC-dependent NFAT activation was confirmed in both cultured TM and in TM in an in vivo UPEC infectious rat orchitis model. Elevated expression of NFATC2-regulated anti-inflammatory cytokines was found in TM (IL-4, IL-13 and PM (IL-3, IL-4, IL-13. NFATC2 is activated by rapid influx of calcium, an activity delineated to the pore forming toxin alpha-hemolysin by bacterial mutant analysis. Alpha-hemolysin suppressed IL-6 and TNF-α cytokine release from PM and caused differential activation of MAP kinase and AP-1 signaling pathways in TM and PM leading to reciprocal expression of key pro-inflammatory cytokines in PM (IL-1α, IL-1β, IL-6 downregulated and TM (IL-1β, IL-6 upregulated. In addition, unlike PM, LPS-treated TM were refractory to NFκB activation shown by the absence of degradation of IκBα and lack of pro-inflammatory cytokine secretion (IL-6, TNF-α. Taken together, these results suggest a mechanism to the conundrum by which TM initiate immune responses to bacteria, while maintaining testicular immune privilege with its ability to tolerate neo-autoantigens expressed on developing spermatogenic cells.

  12. Candida albicans infection of Caenorhabditis elegans induces antifungal immune defenses.

    Directory of Open Access Journals (Sweden)

    Read Pukkila-Worley

    2011-06-01

    Full Text Available Candida albicans yeast cells are found in the intestine of most humans, yet this opportunist can invade host tissues and cause life-threatening infections in susceptible individuals. To better understand the host factors that underlie susceptibility to candidiasis, we developed a new model to study antifungal innate immunity. We demonstrate that the yeast form of C. albicans establishes an intestinal infection in Caenorhabditis elegans, whereas heat-killed yeast are avirulent. Genome-wide, transcription-profiling analysis of C. elegans infected with C. albicans yeast showed that exposure to C. albicans stimulated a rapid host response involving 313 genes (124 upregulated and 189 downregulated, ~1.6% of the genome many of which encode antimicrobial, secreted or detoxification proteins. Interestingly, the host genes affected by C. albicans exposure overlapped only to a small extent with the distinct transcriptional responses to the pathogenic bacteria Pseudomonas aeruginosa or Staphylococcus aureus, indicating that there is a high degree of immune specificity toward different bacterial species and C. albicans. Furthermore, genes induced by P. aeruginosa and S. aureus were strongly over-represented among the genes downregulated during C. albicans infection, suggesting that in response to fungal pathogens, nematodes selectively repress the transcription of antibacterial immune effectors. A similar phenomenon is well known in the plant immune response, but has not been described previously in metazoans. Finally, 56% of the genes induced by live C. albicans were also upregulated by heat-killed yeast. These data suggest that a large part of the transcriptional response to C. albicans is mediated through "pattern recognition," an ancient immune surveillance mechanism able to detect conserved microbial molecules (so-called pathogen-associated molecular patterns or PAMPs. This study provides new information on the evolution and regulation of the innate

  13. Asymptomatic bacteriuria Escherichia coli are live biotherapeutics for UTI.

    Science.gov (United States)

    Rudick, Charles N; Taylor, Aisha K; Yaggie, Ryan E; Schaeffer, Anthony J; Klumpp, David J

    2014-01-01

    Urinary tract infections (UTI) account for approximately 8 million clinic visits annually with symptoms that include acute pelvic pain, dysuria, and irritative voiding. Empiric UTI management with antimicrobials is complicated by increasing antimicrobial resistance among uropathogens, but live biotherapeutics products (LBPs), such as asymptomatic bacteriuria (ASB) strains of E. coli, offer the potential to circumvent antimicrobial resistance. Here we evaluated ASB E. coli as LBPs, relative to ciprofloxacin, for efficacy against infection and visceral pain in a murine UTI model. Visceral pain was quantified as tactile allodynia of the pelvic region in response to mechanical stimulation with von Frey filaments. Whereas ciprofloxacin promoted clearance of uropathogenic E. coli (UPEC), it did not reduce pelvic tactile allodynia, a measure of visceral pain. In contrast, ASB E. coli administered intravesically or intravaginally provided comparable reduction of allodynia similar to intravesical lidocaine. Moreover, ASB E. coli were similarly effective against UTI allodynia induced by Proteus mirabilis, Enterococccus faecalis and Klebsiella pneumoniae. Therefore, ASB E. coli have anti-infective activity comparable to the current standard of care yet also provide superior analgesia. These studies suggest that ASB E. coli represent novel LBPs for UTI symptoms.

  14. Nanodiamonds facilitate killing of intracellular uropathogenic E. coli in an in vitro model of urinary tract infection pathogenesis.

    Science.gov (United States)

    Iyer, Janaki Kannan; Dickey, Alexia; Rouhani, Parvaneh; Kaul, Anil; Govindaraju, Nirmal; Singh, Raj Narain; Kaul, Rashmi

    2018-01-01

    About 25-44% of women will experience at least one episode of recurrent UTI and the causative agent in over 70% of UTI cases is uropathogenic Escherichia coli (UPEC). UPEC cause recurrent UTI by evading the bladder's innate immune system through internalization into the bladder epithelium where antibiotics cannot reach or be effective. Thus, it is important to develop novel therapeutics to eliminate these intracellular pathogens. Nanodiamonds (NDs) are biocompatible nanomaterials that serve as promising candidates for targeted therapeutic applications. The objective of the current study was to investigate if 6 or 25 nm NDs can kill extracellular and intracellular UPEC in infected bladder cells. We utilized the human bladder epithelial cell line, T24, and an invasive strain of UPEC that causes recurrent UTI. We found that acid-purified 6 nm NDs displayed greater antibacterial properties towards UPEC than 25 nm NDs (11.5% vs 94.2% CFU/mL at 100 μg/mL of 6 and 25 nm, respectively; P<0.001). Furthermore, 6 nm NDs were better than 25 nm NDs in reducing the number of UPEC internalized in T24 bladder cells (46.1% vs 81.1% CFU/mL at 100 μg/mL of 6 and 25 nm, respectively; P<0.01). Our studies demonstrate that 6 nm NDs interacted with T24 bladder cells in a dose-dependent manner and were internalized in 2 hours through an actin-dependent mechanism. Finally, internalization of NDs was required for reducing the number of intracellular UPEC in T24 bladder cells. These findings suggest that 6 nm NDs are promising candidates to treat recurrent UTIs.

  15. Nanodiamonds facilitate killing of intracellular uropathogenic E. coli in an in vitro model of urinary tract infection pathogenesis.

    Directory of Open Access Journals (Sweden)

    Janaki Kannan Iyer

    Full Text Available About 25-44% of women will experience at least one episode of recurrent UTI and the causative agent in over 70% of UTI cases is uropathogenic Escherichia coli (UPEC. UPEC cause recurrent UTI by evading the bladder's innate immune system through internalization into the bladder epithelium where antibiotics cannot reach or be effective. Thus, it is important to develop novel therapeutics to eliminate these intracellular pathogens. Nanodiamonds (NDs are biocompatible nanomaterials that serve as promising candidates for targeted therapeutic applications. The objective of the current study was to investigate if 6 or 25 nm NDs can kill extracellular and intracellular UPEC in infected bladder cells. We utilized the human bladder epithelial cell line, T24, and an invasive strain of UPEC that causes recurrent UTI. We found that acid-purified 6 nm NDs displayed greater antibacterial properties towards UPEC than 25 nm NDs (11.5% vs 94.2% CFU/mL at 100 μg/mL of 6 and 25 nm, respectively; P<0.001. Furthermore, 6 nm NDs were better than 25 nm NDs in reducing the number of UPEC internalized in T24 bladder cells (46.1% vs 81.1% CFU/mL at 100 μg/mL of 6 and 25 nm, respectively; P<0.01. Our studies demonstrate that 6 nm NDs interacted with T24 bladder cells in a dose-dependent manner and were internalized in 2 hours through an actin-dependent mechanism. Finally, internalization of NDs was required for reducing the number of intracellular UPEC in T24 bladder cells. These findings suggest that 6 nm NDs are promising candidates to treat recurrent UTIs.

  16. Cotrimoxazole-Induced Hypoglycemia in an HIV-Infected Patient

    Directory of Open Access Journals (Sweden)

    Christine A Hughes

    2001-01-01

    Full Text Available A case of cotrimoxazole-induced hypoglycemia is described in a male patient infected with HIV. Ten days after initiating high dose cotrimoxazole for suspected Pneumocystis carinii pneumonia, the patient developed neuroglycopenic symptoms and diaphoresis. Blood glucose levels were repeatedly low, with elevated insulin and C-peptide levels despite multiple intravenous bolus doses and infusions of dextrose. Hypoglycemia resolved after approximately 36 h of treatment with dextrose and discontinuation of cotrimoxazole. A review of reported cases of hypoglycemia associated with cotrimoxazole is provided, including information about onset, risk factors and possible mechanism.

  17. Vaccination with DNA encoding truncated enterohemorrhagic Escherichia coli (EHEC factor for adherence-1 gene (efa-1’ confers protective immunity to mice infected with E. coli O157:H7

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    Roberto eRiquelme-Neira

    2016-01-01

    Full Text Available Enterohemorrhagic Escherichia coli (EHEC O157:H7 is the predominant causative agent of hemorrhagic colitis in humans and is the cause of haemolytic uraemic syndrome and other illnesses. Cattle have been implicated as the main reservoir of this organism. Here, we evaluated the immunogenicity and protective efficacy of a DNA vaccine encoding conserved sequences of truncated EHEC factor for adherence-1 (efa-1’ in a mouse model. Intranasal administration of plasmid DNA carrying the efa-1’ gene (pVAXefa-1’ into C57BL/6 mice elicited both humoral and cellular immune responses. In animals immunized with pVAXefa-1`, EHEC-secreted protein-specific IgM and IgG antibodies were detected in sera at day 45. Anti-EHEC-secreted protein sIgA was also detected in nasal and bronchoalveolar lavages. In addition, antigen-specific T-cell-proliferation, IL-10 and IFN-γ were observed upon re-stimulation with either heat-killed bacteria or EHEC-secreted proteins. Vaccinated animals were also protected against challenge with E. coli O157:H7 strain EDL933. These results suggest that DNA vaccine encoding efa-1´ have therapeutic potential in interventions against EHEC infections. This approach could lead to a new strategy in the production of vaccines that prevent infections in cattle.

  18. Age-related susceptibility to infection with diarrheagenic E. coli in infants from peri-urban areas of Lima, Peru

    Science.gov (United States)

    Ochoa, Theresa J.; Ecker, Lucie; Barletta, Francesca; Mispireta, Mónica L.; Gil, Ana I.; Contreras, Carmen; Molina, Margarita; Amemiya, Isabel; Verastegui, Hector; Hall, Eric R.; Cleary, Thomas G.; Lanata, Claudio F.

    2009-01-01

    Background Diarrheagenic E. coli are being recognized as important pediatric enteropathogens worldwide. However, it is unclear whether there are differences in age-related susceptibility to specific agents, especially among infants. Methods We conducted a passive surveillance diarrhea cohort study of 1034 children from 2 to 12 months of age in Lima, Perú. Control stool samples were collected from randomly selected children without diarrhea. All samples were analyzed for common enteric pathogens and for the diarrheagenic E. coli by a multiplex real-time PCR. Results The most commonly isolated pathogens from 1065 diarrheal episodes were the diarrheagenic E. coli (31%), including enteroaggregative (15.1%) and enteropathogenic E. coli (EPEC) (7.6%). Diarrheagenic E. coli, Campylobacter and rotavirus were more frequently isolated from infants ≥ 6m. Diffusely adherent E. coli and enterotoxigenic E. coli (ETEC) were more frequently isolated in diarrheal samples than in controls in older infants (pfactors and with increased exposure to contaminated food and water. PMID:19857163

  19. Transurethral instillation with fusion protein MrpH.FimH induces protective innate immune responses against uropathogenic Escherichia coli and Proteus mirabilis.

    Science.gov (United States)

    Habibi, Mehri; Asadi Karam, Mohammad Reza; Bouzari, Saeid

    2016-06-01

    Urinary tract infections (UTIs) are among the most common infections in human. Innate immunity recognizes pathogen-associated molecular patterns (PAMPs) by Toll-like receptors (TLRs) to activate responses against pathogens. Recently, we demonstrated that MrpH.FimH fusion protein consisting of MrpH from Proteus mirabilis and FimH from Uropathogenic Escherichia coli (UPEC) results in the higher immunogenicity and protection, as compared with FimH and MrpH alone. In this study, we evaluated the innate immunity and adjuvant properties induced by fusion MrpH.FimH through in vitro and in vivo methods. FimH and MrpH.FimH were able to induce significantly higher IL-8 and IL-6 responses than untreated or MrpH alone in cell lines tested. The neutrophil count was significantly higher in the fusion group than other groups. After 6 h, IL-8 and IL-6 production reached a peak, with a significant decline at 24 h post-instillation in both bladder and kidney tissues. Mice instilled with the fusion and challenged with UPEC or P. mirabilis showed a significant decrease in the number of bacteria in bladder and kidney compared to control mice. The results of these studies demonstrate that the use of recombinant fusion protein encoding TLR-4 ligand represents an effective vaccination strategy that does not require the use of a commercial adjuvant. Furthermore, MrpH.FimH was presented as a promising vaccine candidate against UTIs caused by UPEC and P. mirabilis. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  20. In vitro secretion profiles of interleukin (IL-1beta, IL-6, IL-8, IL-10, and TNF alpha after selective infection with Escherichia coli in human fetal membranes

    Directory of Open Access Journals (Sweden)

    Maida-Claros Rolando

    2007-12-01

    Full Text Available Abstract Background Chorioamniotic membranes infection is a pathologic condition in which an abnormal secretion of proinflammatory cytokines halts fetal immune tolerance. The aim of the present study was to evaluate the functional response of human chorioamniotic membranes, as well as the individual contribution of the amnion and choriodecidua after stimulation with Escherichia coli, a pathogen associated with preterm labor. Methods Explants of chorioamniotic membranes from 10 women (37–40 weeks of gestation were mounted and cultured in a Transwell system, which allowed us to test the amnion and choriodecidua compartments independently. Escherichia coli (1 × 10 6 CFU/mL was added to either the amniotic or the choriodecidual regions or both; after a 24-h incubation, the secretion of IL-1beta, IL-6, TNFalpha, IL-8, and IL-10 in both compartments was measured using a specific ELISA. Data were analyzed by Kruskal-Wallis one-way analysis of variance. Results After stimulation with Escherichia coli, the choriodecidua compartment showed an increase in the secretion of IL-1beta (21-fold, IL-6 (2-fold, IL-8 (6-fold, and IL-10 (37-fold, regardless of which side of the membrane was stimulated; TNFalpha secretion augmented (22-fold also but only when the stimulus was applied simultaneously to both sides. When the amnion was stimulated directly, the level of IL-1beta (13-fold rose significantly; however, the increase in IL-8 secretion was larger (20-fold, regardless of the primary site of infection. TNFalpha secretion in the amnion compartment rose markedly only when Escherichia coli was simultaneously applied to both sides. Conclusion Selective stimulation of fetal membranes with Escherichia coli results in a differential production of IL-1beta, IL-6, TNFalpha, IL-8, and IL-10. These tissues were less responsive when the amnion side was stimulated. This is in agreement with the hypothesis that the choriodecidua may play a primary role during an ascending

  1. Binding of a nitroxyl to radiation-induced DNA transients in repair and repair deficient of E. coli K-12

    Energy Technology Data Exchange (ETDEWEB)

    Wold, E; Brustad, T [Norsk Hydros Institutt for Kreftforskning, Oslo

    1975-01-01

    Binding of tritiated 2,2,6,6-tetramethyl-4-piperidone-N-oxyl (/sup 3/H-TAN) to radiation-induced DNA-transients in E. coli K-12 strains AB 1157 and JO 307 rec A uvr A has been studied under in vivo conditions. After irradiation the cells were washed and resuspended in growth medium and left overnight at 37 deg C. Within an uncertainty of about 10 %, no effect of repair could be detected on the yield of TAN bound to DNA for any of the strains. During the period after resuspension TAN or fragments of TAN leaked out of the irradiated cell samples. This leakage may be attributed to semi-permanent association between TAN and radiation-induced radicals within the cell. The relevance of different interactions between TAN and transients in DNA is discussed.

  2. Porphyromonas Gingivalis and E-coli induce different cytokine production patterns in pregnant women.

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    Marijke M Faas

    Full Text Available OBJECTIVE: Pregnant individuals of many species, including humans, are more sensitive to various bacteria or their products as compared with non-pregnant individuals. Pregnant individuals also respond differently to different bacteria or their products. Therefore, in the present study, we evaluated whether the increased sensitivity of pregnant women to bacterial products and their heterogeneous response to different bacteria was associated with differences in whole blood cytokine production upon stimulation with bacteria or their products. METHODS: Blood samples were taken from healthy pregnant and age-matched non-pregnant women and ex vivo stimulated with bacteria or LPS from Porphyromonas Gingivalis (Pg or E-coli for 24 hrs. TNFα, IL-1ß, IL-6, IL-12 and IL-10 were measured using a multiplex Luminex system. RESULTS: We observed a generally lower cytokine production after stimulation with Pg bacteria or it's LPS as compared with E-coli bacteria. However, there was also an effect of pregnancy upon cytokine production: in pregnant women the production of IL-6 upon Pg stimulation was decreased as compared with non-pregnant women. After stimulation with E-coli, the production of IL-12 and TNFα was decreased in pregnant women as compared with non-pregnant women. CONCLUSION: Our results showed that cytokine production upon bacterial stimulation of whole blood differed between pregnant and non-pregnant women, showing that the increased sensitivity of pregnant women may be due to differences in cytokine production. Moreover, pregnancy also affected whole blood cytokine production upon Pg or E-coli stimulation differently. Thus, the different responses of pregnant women to different bacteria or their products may result from variations in cytokine production.

  3. Exposure to the proton scavenger glycine under alkaline conditions induces Escherichia coli viability loss.

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    Donna Vanhauteghem

    Full Text Available Our previous work described a clear loss of Escherichia coli (E. coli membrane integrity after incubation with glycine or its N-methylated derivatives N-methylglycine (sarcosine and N,N-dimethylglycine (DMG, but not N,N,N-trimethylglycine (betaine, under alkaline stress conditions. The current study offers a thorough viability analysis, based on a combination of real-time physiological techniques, of E. coli exposed to glycine and its N-methylated derivatives at alkaline pH. Flow cytometry was applied to assess various physiological parameters such as membrane permeability, esterase activity, respiratory activity and membrane potential. ATP and inorganic phosphate concentrations were also determined. Membrane damage was confirmed through the measurement of nucleic acid leakage. Results further showed no loss of esterase or respiratory activity, while an instant and significant decrease in the ATP concentration occurred upon exposure to either glycine, sarcosine or DMG, but not betaine. There was a clear membrane hyperpolarization as well as a significant increase in cellular inorganic phosphate concentration. Based on these results, we suggest that the inability to sustain an adequate level of ATP combined with a decrease in membrane functionality leads to the loss of bacterial viability when exposed to the proton scavengers glycine, sarcosine and DMG at alkaline pH.

  4. Exposure to the Proton Scavenger Glycine under Alkaline Conditions Induces Escherichia coli Viability Loss

    Science.gov (United States)

    Vanhauteghem, Donna; Janssens, Geert Paul Jules; Lauwaerts, Angelo; Sys, Stanislas; Boyen, Filip; Cox, Eric; Meyer, Evelyne

    2013-01-01

    Our previous work described a clear loss of Escherichia coli (E. coli) membrane integrity after incubation with glycine or its N-methylated derivatives N-methylglycine (sarcosine) and N,N-dimethylglycine (DMG), but not N,N,N-trimethylglycine (betaine), under alkaline stress conditions. The current study offers a thorough viability analysis, based on a combination of real-time physiological techniques, of E. coli exposed to glycine and its N-methylated derivatives at alkaline pH. Flow cytometry was applied to assess various physiological parameters such as membrane permeability, esterase activity, respiratory activity and membrane potential. ATP and inorganic phosphate concentrations were also determined. Membrane damage was confirmed through the measurement of nucleic acid leakage. Results further showed no loss of esterase or respiratory activity, while an instant and significant decrease in the ATP concentration occurred upon exposure to either glycine, sarcosine or DMG, but not betaine. There was a clear membrane hyperpolarization as well as a significant increase in cellular inorganic phosphate concentration. Based on these results, we suggest that the inability to sustain an adequate level of ATP combined with a decrease in membrane functionality leads to the loss of bacterial viability when exposed to the proton scavengers glycine, sarcosine and DMG at alkaline pH. PMID:23544135

  5. Effects of Bos taurus autosome 9-located quantitative trait loci haplotypes on the disease phenotypes of dairy cows with experimentally induced Escherichia coli mastitis

    DEFF Research Database (Denmark)

    Khatun, Momena; Sørensen, Peter; Jørgensen, Hanne Birgitte Hede

    2013-01-01

    Several quantitative trait loci (QTL) affecting mastitis incidence and mastitis-related traits such as somatic cell score exist in dairy cows. Previously, QTL haplotypes associated with susceptibility to Escherichia coli mastitis in Nordic Holstein-Friesian (HF) cows were identified on Bos taurus...... autosome 9. In the present study, we induced experimental E. coli mastitis in Danish HF cows to investigate the effect of 2 E. coli mastitis-associated QTL haplotypes on the cows' disease phenotypes and recovery in early lactation. Thirty-two cows were divided in 2 groups bearing haplotypes with either low...... the HH group did. However, we also found interactions between the effects of haplotype and biopsy for body temperature, heart rate, and PMNL. In conclusion, when challenged with E. coli mastitis, HF cows with the specific Bos taurus autosome 9-located QTL haplotypes were associated with differences...

  6. Human Papillomavirus 16 Infection Induces VAP-Dependent Endosomal Tubulation.

    Science.gov (United States)

    Siddiqa, Abida; Massimi, Paola; Pim, David; Broniarczyk, Justyna; Banks, Lawrence

    2018-03-15

    Human papillomavirus (HPV) infection involves complex interactions with the endocytic transport machinery, which ultimately facilitates the entry of the incoming viral genomes into the trans -Golgi network (TGN) and their subsequent nuclear entry during mitosis. The endosomal pathway is a highly dynamic intracellular transport system, which consists of vesicular compartments and tubular extensions, although it is currently unclear whether incoming viruses specifically alter the endocytic machinery. In this study, using MICAL-L1 as a marker for tubulating endosomes, we show that incoming HPV-16 virions induce a profound alteration in global levels of endocytic tubulation. In addition, we also show a critical requirement for the endoplasmic reticulum (ER)-anchored protein VAP in this process. VAP plays an essential role in actin nucleation and endosome-to-Golgi transport. Indeed, the loss of VAP results in a dramatic decrease in the level of endosomal tubulation induced by incoming HPV-16 virions. This is also accompanied by a marked reduction in virus infectivity. In VAP knockdown cells, we see that the defect in virus trafficking occurs after capsid disassembly but prior to localization at the trans -Golgi network, with the incoming virion-transduced DNA accumulating in Vps29/TGN46-positive hybrid vesicles. Taken together, these studies demonstrate that infection with HPV-16 virions induces marked alterations of endocytic transport pathways, some of which are VAP dependent and required for the endosome-to-Golgi transport of the incoming viral L2/DNA complex. IMPORTANCE Human papillomavirus infectious entry involves multiple interactions with the endocytic transport machinery. In this study, we show that incoming HPV-16 virions induce a dramatic increase in endocytic tubulation. This tubulation requires ER-associated VAP, which plays a critical role in ensuring the delivery of cargoes from the endocytic compartments to the trans -Golgi network. Indeed, the loss of

  7. Incidence of chemotherapy-induced neutropenia in HIV-infected and ...

    African Journals Online (AJOL)

    show an increased incidence of breast cancer among HIV-infected ... on CIN in patients with breast cancer and HIV infection are scarce, ...... Crawford J. Pegfilgrastim for the prevention of chemotherapy-induced neutropenic complications, with.

  8. Characteristics of Shigatoxin-Producing Escherichia coli Strains Isolated during 2010–2014 from Human Infections in Switzerland

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    Lisa Fierz

    2017-08-01

    Full Text Available Objectives: The aim of this study was to characterize a collection of 95 Shigatoxin-producing E.coli (STEC isolated from human patients in Switzerland during 2010–2014.Methods: We performed O and H serotyping and molecular subtyping.Results: The five most common serogroups were O157, O145, O26, O103, and O146. Of the 95 strains, 35 (36.8% carried stx1 genes only, 43 strains (45.2% carried stx2 and 17 (17.9% harbored combinations of stx1 and stx2 genes. Stx1a (42 strains and stx2a (32 strains were the most frequently detected stx subtypes. Genes for intimin (eae, hemolysin (hly, iron-regulated adhesion (iha, and the subtilase cytotoxin subtypes subAB1, subAB2-1, subAB2-2, or subAB2-3 were detected in 70.5, 83.2, 74.7, and 20% of the strains, respectively. Multilocus sequence typing assigned the majority (58.9% of the isolates to five different clonal complexes (CC, 11, 32, 29, 20, and 165, respectively. CC11 included all O157:[H7] and O55:[H7] isolates. CC32 comprised O145:[H28] isolates, and O145:[H25] belonged to sequence type (ST 342. CC29 contained isolates of the O26:[H11], O111:[H8] and O118:[Hnt] serogroups, and CC20 encompassed isolates of O51:H49/[Hnt] and O103:[H2]. CC165 included isolates typed O80:[H2]-ST301, all harboring stx2d, eae-ξ, hly, and 66.7% additionally harboring iha. All O80:[H2]-ST301 strains harbored at least 7 genes carried by pS88, a plasmid associated with extraintestinal virulence. Compared to data from Switzerland from the years 2000–2009, an increase of the proportion of non-O157 STEC infections was observed as well as an increase of infections due to STEC O146. By contrast, the prevalence of the highly virulent German clone STEC O26:[H11]-ST29 decreased from 11.3% during 2000–2009 to 1.1% for the time span 2010–2014. The detection of O80:[H2]-ST301 harboring stx2d, eae-ξ, hly, iha, and pS88 related genes suggests an ongoing emergence in Switzerland of an unusual, highly pathogenic STEC serotype

  9. Hypophosphatemic osteomalacia induced by tenofovir in HIV-infected patients.

    Science.gov (United States)

    Mateo, Lourdes; Holgado, Susana; Mariñoso, Maria Luisa; Pérez-Andrés, Ricard; Bonjoch, Anna; Romeu, Joan; Olivé, Alejandro

    2016-05-01

    Tenofovir disoproxil fumarate (TDF) is an adenine analogue reverse transcription inhibitor widely used in first-line treatment of human immunodeficiency virus (HIV) infection and also in hepatitis B virus infection. Its use has been linked to sporadic Fanconi syndrome, renal failure and bone disease. We present the clinical characteristics of tenofovir-induced osteomalacia, discuss bone biopsy findings, describe predisposing factors and compare our results with other reported cases. We describe five cases of hypophosphatemic osteomalacia induced by TDF and recorded at the rheumatology service of a university hospital between 2010 and 2014. We also report the characteristics of bone biopsies of this pathology, which have not been previously described. We include a review of published cases of proximal renal tubulopathy (PRT) and osteomalacia induced by TDF (PubMed 1995-2014; keywords: osteomalacia, tenofovir, Fanconi syndrome, hypophosphatemic osteomalacia, proximal renal tubulopathy, bone biopsy). Five HIV patients who developed hypophosphatemic osteomalacia under TDF treatment (>5 years) presented increasing bone pain and a progressive inability to walk without assistance as a result of multiple insufficiency fractures. Bone biopsy performed in three patients after tetracycline labelling showed increased osteoid thickness, confirming osteomalacia. A literature review retrieved 17 publications on this condition, including 53 cases: 26 patients developed isolated PRT, 25 presented PRT and with multiple insufficiency fractures and two presented isolated bone disease, including osteomalacia and osteoporosis. Rheumatologists should be alert to this complication in patients receiving tenofovir. The main complaint reported by these patients is diffuse pain, predominantly in the lower limbs, indicating multiple stress fractures. Serum phosphate and appropriate screening for abnormal proximal tubule function should be monitored. Bone scintigraphy should be carried out in

  10. Frequency of Fimbrial Virulence Genes (fim, pap, sfa in Escherichia Coli Isolated from the Patients with Urinary Tract Infections from selective hospitals of Tehran, Boroujerd and Sanandej City in 2015-2016

    Directory of Open Access Journals (Sweden)

    mohsen mirzaee

    2017-02-01

    Full Text Available Introduction: Urinary tract infection (UTI caused by E coli is one of the most common diseases in community. Colonization of E. coli and its attachment to the uroepithelium are mediated by adhesions such as P, Fim and S fimbriae. The present study was aimed to evaluate the prevalence of fimbrial virulence genes in Escherichia coli (E. coli isolates from the patients with urinary tract infection in Tehran, Boroujerd and Sanandaj cities, Iran. Methods: In this descriptive cross sectional study, 150 clinical isolates of uropathogenic E.coli were collected from the patients with urinary tract infection. All bacterial isolates were identified by standard biochemical laboratory methods; the fim, pap and sfa genes were detected using the PCR and Multiplex-PCR methods. Results: One hundred forty-five (96.66% isolates were positive for fim gene, one hundred forty (93.33% isolates were positive for pap gene and seven (4.66 isolates were positive for sfa gene. Whole of the isolates were possessed at least one of the three virulence genes. Six (4% isolates were positive for all genes. Conclusion: The findings of this study showed the high frequency of fim and P fimbriae among uropathogenic E.coli isolates from the patients with urinary tract infection. Because of the higher prevalence of UTI in the presence of these genes, detection of the genes in urine samples may help in more suspicious and rapid management of UTI.

  11. Ex vivo and in vivo evaluation of microemulsion based transdermal delivery of E. coli specific T4 bacteriophage: A rationale approach to treat bacterial infection.

    Science.gov (United States)

    Rastogi, Vaibhav; Yadav, Pragya; Verma, Anurag; Pandit, Jayanta K

    2017-09-30

    This study is focused on the development and evaluation of transdermal delivery of E. coli-specific T4 bacteriophages both ex-vivo and in-vivo using microemulsion as delivery carrier in eradicating the infection caused by E. coli. Microemulsions were prepared by mixing selected oil, surfactants and aqueous phase containing bacteriophages. The formulations were subjected to physicochemical characterization, ex-vivo and in-vivo permeation, stability studies, histological and immunofluorescence examination. The colloidal system exhibits a uniform size distribution, of finite size (150-320nm). Transmission electron microscopy revealed the encapsulation of bacteriophage in the aqueous globule. Ex-vivo permeation across skin was successfully achieved as 6×10 6 PFU/mL and 6.7×10 6 PFU/mL of T4 permeated from ME 6% and 10%, respectively. ME 6% was found to be thermodynamically stable and in-vivo permeation resulted in 5.49×10 5 PFU/mL of bacteriophages in the blood of the E. coli challenged rats, while 2.48×10 5 PFU/mL was detected in germ free rats, at the end of the study. Infected rats that were treated with bacteriophage were survived while significant mortality was observed in others. Histological and IL-6 immunofluorescence examination of the tissues revealed the efficacy/safety of the therapy. The microemulsion-based transdermal delivery of bacteriophage could be a promising approach to treat the infections caused by antibiotic-resistant bacteria. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Escherichia coli morphological changes and lipid A removal induced by reduced pressure nitrogen afterglow exposure.

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    Hayat Zerrouki

    Full Text Available Lipid A is a major hydrophobic component of lipopolysaccharides (endotoxin present in the membrane of most Gram-negative bacteria, and the major responsible for the bioactivity and toxicity of the endotoxin. Previous studies have demonstrated that the late afterglow region of flowing post-discharges at reduced pressure (1-20 Torr can be used for the sterilization of surfaces and of the reusable medical instrumentation. In the present paper, we show that the antibacterial activity of a pure nitrogen afterglow can essentially be attributed to the large concentrations of nitrogen atoms present in the treatment area and not to the UV radiation of the afterglow. In parallel, the time variation of the inactivation efficiency quantified by the log reduction of the initial Escherichia coli (E. coli population is correlated with morphologic changes observed on the bacteria by scanning electron microscopy (SEM for increasing afterglow exposure times. The effect of the afterglow exposure is also studied on pure lipid A and on lipid A extracted from exposed E. coli bacteria. We report that more than 60% of lipid A (pure or bacteria-extracted are lost with the used operating conditions (nitrogen flow QN2 = 1 standard liter per minute (slpm, pressure p = 5 Torr, microwave injected power PMW = 200 W, exposure time: 40 minutes. The afterglow exposure also results in a reduction of the lipid A proinflammatory activity, assessed by the net decrease of the redox-sensitive NFκB transcription factor nuclear translocation in murine aortic endothelial cells stimulated with control vs afterglow-treated (pure and extracted lipid A. Altogether these results point out the ability of reduced pressure nitrogen afterglows to neutralize the cytotoxic components in Gram-negative bacteria.

  13. Effect of carprofen treatment following experimentally induced Escherichia coli mastitis in primiparous cows.

    Science.gov (United States)

    Vangroenweghe, F; Duchateau, L; Boutet, P; Lekeux, P; Rainard, P; Paape, M J; Burvenich, C

    2005-07-01

    Acute Escherichia coli mastitis is one of the major sources of economic loss in the dairy industry due to reduced milk production, treatment costs, discarded milk, and occasional fatal disease. Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used as adjunctive therapy to antibiotics. The objective of the current study was to evaluate the effect of carprofen treatment following infusion of Escherichia coli into the mammary glands of primiparous cows during the periparturient period. Severity of mastitis was scored based on the average milk production in the uninfected quarters on d +2 postinoculation and a clinical severity score. Carprofen was administered intravenously at 9 h postchallenge, when clinical signs of mastitis appeared. In previous work, efficacy of NSAIDs was mainly evaluated using clinical symptoms. In the present study, the effect of carprofen on innate immune response was also assessed by quantification of inflammatory mediators. All primiparous cows reacted as moderate responders throughout the experimental period. Primiparous cows were intramammarily inoculated with 1 x 10(4) cfu of E. coli P4:O32 in 2 left quarters. Analysis of blood and milk parameters, including IL-8, complement component C5a, lipopolysaccharide-binding protein (LBP), soluble CD14, prostaglandin E2, and thromboxane B2 was performed from d 0 to d +6 relative to intramammary inoculation. Rectal temperature in carprofen-treated animals was lower than in control animals at 3 and 6 h posttreatment. Treatment also restored the decreased reticulorumen motility that occurs during E. coli mastitis to preinfection levels faster than in control animals. Carprofen treatment resulted in an earlier normalization of the clinical severity score. Eicosanoid (prostaglandin E2 and thromboxane B2) production in milk tended to be inhibited by carprofen. No significant differences in the kinetic patterns of somatic cell count, IL-8, complement component C5a, LBP, and soluble CD14 were

  14. Adherence to abiotic surface induces SOS response in Escherichia coli K-12 strains under aerobic and anaerobic conditions.

    Science.gov (United States)

    Costa, Suelen B; Campos, Ana Carolina C; Pereira, Ana Claudia M; de Mattos-Guaraldi, Ana Luiza; Júnior, Raphael Hirata; Rosa, Ana Cláudia P; Asad, Lídia M B O

    2014-09-01

    During the colonization of surfaces, Escherichia coli bacteria often encounter DNA-damaging agents and these agents can induce several defence mechanisms. Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species (ROS) generated by chemical and physical agents or by metabolism. In this work, we have evaluated whether the interaction with an abiotic surface by mutants derived from E. coli K-12 deficient in some enzymes that are part of BER causes DNA damage and associated filamentation. Moreover, we studied the role of endonuclease V (nfi gene; 1506 mutant strain) in biofilm formation. Endonuclease V is an enzyme that is involved in DNA repair of nitrosative lesions. We verified that endonuclease V is involved in biofilm formation. Our results showed more filamentation in the xthA mutant (BW9091) and triple xthA nfo nth mutant (BW535) than in the wild-type strain (AB1157). By contrast, the mutant nfi did not present filamentation in biofilm, although its wild-type strain (1466) showed rare filaments in biofilm. The filamentation of bacterial cells attaching to a surface was a consequence of SOS induction measured by the SOS chromotest. However, biofilm formation depended on the ability of the bacteria to induce the SOS response since the mutant lexA Ind(-) did not induce the SOS response and did not form any biofilm. Oxygen tension was an important factor for the interaction of the BER mutants, since these mutants exhibited decreased quantitative adherence under anaerobic conditions. However, our results showed that the presence or absence of oxygen did not affect the viability of BW9091 and BW535 strains. The nfi mutant and its wild-type did not exhibit decreased biofilm formation under anaerobic conditions. Scanning electron microscopy was also performed on the E. coli K-12 strains that had adhered to the glass, and we observed the presence of a structure similar to an extracellular matrix that depended on the

  15. Meta-Analysis of Transcriptional Responses to Mastitis-Causing Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Sidra Younis

    Full Text Available Bovine mastitis is a widespread disease in dairy cows, and is often caused by bacterial mammary gland infection. Mastitis causes reduced milk production and leads to excessive use of antibiotics. We present meta-analysis of transcriptional profiles of bovine mastitis from 10 studies and 307 microarrays, allowing identification of much larger sets of affected genes than any individual study. Combining multiple studies provides insight into the molecular effects of Escherichia coli infection in vivo and uncovers differences between the consequences of E. coli vs. Staphylococcus aureus infection of primary mammary epithelial cells (PMECs. In udders, live E. coli elicits inflammatory and immune defenses through numerous cytokines and chemokines. Importantly, E. coli infection causes downregulation of genes encoding lipid biosynthesis enzymes that are involved in milk production. Additionally, host metabolism is generally suppressed. Finally, defensins and bacteria-recognition genes are upregulated, while the expression of the extracellular matrix protein transcripts is silenced. In PMECs, heat-inactivated E. coli elicits expression of ribosomal, cytoskeletal and angiogenic signaling genes, and causes suppression of the cell cycle and energy production genes. We hypothesize that heat-inactivated E. coli may have prophylactic effects against mastitis. Heat-inactivated S. aureus promotes stronger inflammatory and immune defenses than E. coli. Lipopolysaccharide by itself induces MHC antigen presentation components, an effect not seen in response to E. coli bacteria. These results provide the basis for strategies to prevent and treat mastitis and may lead to the reduction in the use of antibiotics.

  16. DinB Upregulation Is the Sole Role of the SOS Response in Stress-Induced Mutagenesis in Escherichia coli

    Science.gov (United States)

    Galhardo, Rodrigo S.; Do, Robert; Yamada, Masami; Friedberg, Errol C.; Hastings, P. J.; Nohmi, Takehiko; Rosenberg, Susan M.

    2009-01-01

    Stress-induced mutagenesis is a collection of mechanisms observed in bacterial, yeast, and human cells in which adverse conditions provoke mutagenesis, often under the control of stress responses. Control of mutagenesis by stress responses may accelerate evolution specifically when cells are maladapted to their environments, i.e., are stressed. It is therefore important to understand how stress responses increase mutagenesis. In the Escherichia coli Lac assay, stress-induced point mutagenesis requires induction of at least two stress responses: the RpoS-controlled general/starvation stress response and the SOS DNA-damage response, both of which upregulate DinB error-prone DNA polymerase, among other genes required for Lac mutagenesis. We show that upregulation of DinB is the only aspect of the SOS response needed for stress-induced mutagenesis. We constructed two dinB(oc) (operator-constitutive) mutants. Both produce SOS-induced levels of DinB constitutively. We find that both dinB(oc) alleles fully suppress the phenotype of constitutively SOS-“off” lexA(Ind−) mutant cells, restoring normal levels of stress-induced mutagenesis. Thus, dinB is the only SOS gene required at induced levels for stress-induced point mutagenesis. Furthermore, although spontaneous SOS induction has been observed to occur in only a small fraction of cells, upregulation of dinB by the dinB(oc) alleles in all cells does not promote a further increase in mutagenesis, implying that SOS induction of DinB, although necessary, is insufficient to differentiate cells into a hypermutable condition. PMID:19270270

  17. Infection,

    Science.gov (United States)

    1980-10-16

    characteristic in severe gram-negative sepsis. Hypertriglyceridemia results from an increase in hepatic synthesis in combination with diminished activity of...induced stress, and tissue repair (1). The magnitude and type of nutritional losses caused by an infection reflect both the severity and duration of an... several functional forms of nutrient loss must be anticipated. Functional losses are defined as the within-body losses of nutrients due to infection

  18. Recovery from damage induced by acridine plus near-ultraviolet light in Escherichia coli

    International Nuclear Information System (INIS)

    Wagner, S.; Feldman, A.; Snipes, W.

    1982-01-01

    Escherichia coli cells treated with sublethal doses of acridine plus near-UV light exhibit an effective split-dose recovery response that requires an incubation period of about 30-45 min. Studies of the metabolic requirements for split-dose recovery revealed the following: (a) DNA synthesis is not required for split-dose recovery: (b) inhibition of electron transport or protein synthesis reduces the efficiency of split-dose recovery by about one-half: (c) inhibition of phospholipid synthesis or cell wall synthesis completely eliminates the split-dose recovery response. These results suggest an involvement of membrane repair mechanisms in response to damage by acridine plus near-UV light. Additional evidence for such a process was provided by more direct assays for membrane recovery. It was found that cells treated with sublethal doses of acridine plus near-UV light are sensitive to low concentrations of detergents, and lose that sensitivity upon incubation. Likewise, treated cells are susceptible to lethal osmotic shock, but can recover from this susceptibility if incubated after treatment but prior to exposure to low osmotic conditions. Based on accumulating evidence it is proposed that E. coli cells are capable of repairing membrane damage resulting from exposure to acridine plus near-UV light. (author)

  19. DNA sequence changes in mutation induced by ultraviolet light in the gpt gene on the chromosome of Escherichia coli uvr+ und uvrA cells

    International Nuclear Information System (INIS)

    Sockett, H.; Romac, S.; Hutchinson, F.

    1991-01-01

    Sequence changes in mutations induced by ultraviolet light are reported for the chromosomal Escherichia coli gpt gene in almost isogenic E. coli uvr + and excision-deficient uvrA cells. Differences between the mutagenic spectra are ascribed to preferential removal of photoproducts in the transcribed strand by excision repair in uvr + cells. This conclusion is confirmed by analysis of published results for genes in both uvr + and uvr − cells, showing a similar selective removal of mutagenic products from the transcribed strand of the E. coli lacI gene and of the lambda phage cl repressor gene. Comparison of these data with published results for ultraviolet mutagenesis of gpt on a chromosome in Chinese hamster ovary cells showed that a mutagenic hot spot in mammalian cells is not present in E. coli; the possibility is suggested that the hot spot might arise from localized lack of excision repair. Otherwise, mutagenesis in hamster cells appeared similar to that in E. coli uvr + cells, except there appears to be a smaller fraction of single-base additions and deletions (frameshifts) in mammalian than in bacterial cells. Phenotypes of 6-thioguanine-resistant E. coli showed there is a gene (or genes) other than gpt involved in the utilization of thioguanine by bacteria

  20. The camelliagenin from defatted seeds of Camellia oleifera as antibiotic substitute to treat chicken against infection of Escherichia coli and Staphylococcus aureus.

    Science.gov (United States)

    Ye, Yong; Yang, Qian; Fang, Fei; Li, Yue

    2015-08-18

    Escherichia coli and Staphylococcus aureus are the main pathogens infectious to poultry, and their resistances against antibiotics have become troublesome currently. Biofilm formation is an important reason for drug resistance. Our previous research has found that the extract of Camellia oleifera seeds has lots of pharmacological effects. In order to find the substitute for antibiotics, the saponin was isolated from the defatted C. oleifera seeds with structural identification. Its efficacy was evaluated by the inhibition on amoxicillin-resistant E. coli and erythromycin-resistant S. aureus and therapeutic effect on chicks infected by the two bacteria. The bacterial growth inhibition rate increased and the bacterial count in vivo decreased significantly in dose dependence after administration of the saponin and its combination with amoxicillin or erythromycin, suggesting its antibacterial effect. The saponin identified as camelliagenin shows significant inhibition on the biofilm of E. coli and S. aureus, and it is related to the decrease of mannitol dehydrogenase (MDH) activity and extracellular DNA (eDNA) content. Molecular simulation reveals the strong interaction existing between the saponin and MDH or eDNA. The mechanism of camelliagenin's improvement on antibiotic effects is its interaction with MDH and eDNA in biofilm. The saponin is a prospective substitute of antibiotics, and molecular simulation is a convenient alternative method to find out hopeful candidates of antibiotics substitute.

  1. Giardia co-infection promotes the secretion of antimicrobial peptides beta-defensin 2 and trefoil factor 3 and attenuates attaching and effacing bacteria-induced intestinal disease.

    Science.gov (United States)

    Manko, Anna; Motta, Jean-Paul; Cotton, James A; Feener, Troy; Oyeyemi, Ayodele; Vallance, Bruce A; Wallace, John L; Buret, Andre G

    2017-01-01

    Our understanding of polymicrobial gastrointestinal infections and their effects on host biology remains incompletely understood. Giardia duodenalis is an ubiquitous intestinal protozoan parasite infecting animals and humans. Concomitant infections with Giardia and other gastrointestinal pathogens commonly occur. In countries with poor sanitation, Giardia infection has been associated with decreased incidence of diarrheal disease and fever, and reduced serum inflammatory markers release, via mechanisms that remain obscure. This study analyzed Giardia spp. co-infections with attaching and effacing (A/E) pathogens, and assessed whether and how the presence of Giardia modulates host responses to A/E enteropathogens, and alters intestinal disease outcome. In mice infected with the A/E pathogen Citrobacter rodentium, co-infection with Giardia muris significantly attenuated weight loss, macro- and microscopic signs of colitis, bacterial colonization and translocation, while concurrently enhancing the production and secretion of antimicrobial peptides (AMPs) mouse β-defensin 3 and trefoil factor 3 (TFF3). Co-infection of human intestinal epithelial cells (Caco-2) monolayers with G. duodenalis trophozoites and enteropathogenic Escherichia coli (EPEC) enhanced the production of the AMPs human β-defensin 2 (HBD-2) and TFF3; this effect was inhibited with treatment of G. duodenalis with cysteine protease inhibitors. Collectively, these results suggest that Giardia infections are capable of reducing enteropathogen-induced colitis while increasing production of host AMPs. Additional studies also demonstrated that Giardia was able to directly inhibit the growth of pathogenic bacteria. These results reveal novel mechanisms whereby Giardia may protect against gastrointestinal disease induced by a co-infecting A/E enteropathogen. Our findings shed new light on how microbial-microbial interactions in the gut may protect a host during concomitant infections.

  2. Mapping temperature-induced conformational changes in the Escherichia coli heat shock transcription factor sigma 32 by amide hydrogen exchange

    DEFF Research Database (Denmark)

    Rist, Wolfgang; Jørgensen, Thomas J D; Roepstorff, Peter

    2003-01-01

    Stress conditions such as heat shock alter the transcriptional profile in all organisms. In Escherichia coli the heat shock transcription factor, sigma 32, out-competes upon temperature up-shift the housekeeping sigma-factor, sigma 70, for binding to core RNA polymerase and initiates heat shock...... gene transcription. To investigate possible heat-induced conformational changes in sigma 32 we performed amide hydrogen (H/D) exchange experiments under optimal growth and heat shock conditions combined with mass spectrometry. We found a rapid exchange of around 220 of the 294 amide hydrogens at 37...... degrees C, indicating that sigma 32 adopts a highly flexible structure. At 42 degrees C we observed a slow correlated exchange of 30 additional amide hydrogens and localized it to a helix-loop-helix motif within domain sigma 2 that is responsible for the recognition of the -10 region in heat shock...

  3. Effect of nalidixic acid on repair of single-strand breaks in DNA induced by ionizing irradiation in Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Francia, I [Debreceni Orvostudomanyi Egyetem (Hungary); Okos, A; Hernadi, F J [Institute of Pharmacology, Debrecen (Hungary)

    1978-09-30

    The incidence of DNA single-strand breaks induced by /sup 60/Co irradiation and their repair in E.coli K12 (AB 1157) rec/sup +/ cells were studied by the alkaline sucrose gradient sedimentation method described by McGrath and Williams. For the quantitative analysis of sedimentation profiles we used the s 1/2 values described by Veatch and Okada. The s 1/2 value of non-irradiated controls was 22.4, and after 20 krads irradiation it was found to be 11.7. A postirradiation incubation at 37 /sup 0/C for 60 min increasedthe s 1/2 value from 11.7 to 22.1. Nalidixic acid at low concentration (20-50 ..mu..g/ml) did not block, but at 100 ..mu..g/ml extensively inhibited the above repair process, exhibiting an s 1/2 value of 14.4.

  4. Inducible l-Alanine Exporter Encoded by the Novel Gene ygaW (alaE) in Escherichia coli

    Science.gov (United States)

    Hori, Hatsuhiro; Yoneyama, Hiroshi; Tobe, Ryuta; Ando, Tasuke; Isogai, Emiko; Katsumata, Ryoichi

    2011-01-01

    We previously isolated a mutant hypersensitive to l-alanyl-l-alanine from a non-l-alanine-metabolizing Escherichia coli strain and found that it lacked an inducible l-alanine export system. Consequently, this mutant showed a significant accumulation of intracellular l-alanine and a reduction in the l-alanine export rate compared to the parent strain. When the mutant was used as a host to clone a gene(s) that complements the dipeptide-hypersensitive phenotype, two uncharacterized genes, ygaW and ytfF, and two characterized genes, yddG and yeaS, were identified. Overexpression of each gene in the mutant resulted in a decrease in the intracellular l-alanine level and enhancement of the l-alanine export rate in the presence of the dipeptide, suggesting that their products function as exporters of l-alanine. Since ygaW exhibited the most striking impact on both the intra- and the extracellular l-alanine levels among the four genes identified, we disrupted the ygaW gene in the non-l-alanine-metabolizing strain. The resulting isogenic mutant showed the same intra- and extracellular l-alanine levels as observed in the dipeptide-hypersensitive mutant obtained by chemical mutagenesis. When each gene was overexpressed in the wild-type strain, which does not intrinsically excrete alanine, only the ygaW gene conferred on the cells the ability to excrete alanine. In addition, expression of the ygaW gene was induced in the presence of the dipeptide. On the basis of these results, we concluded that YgaW is likely to be the physiologically most relevant exporter for l-alanine in E. coli and proposed that the gene be redesignated alaE for alanine export. PMID:21531828

  5. Ultraviolet radiation-induced mutability of isogenic uvrA and uvrB strains of Escherichia coli K-12 W3110

    International Nuclear Information System (INIS)

    Barfknecht, T.R.; Smith, K.C.

    1977-01-01

    E. coli K-12 W3110 uvrB5 strain has been shown to have a higher UV induced reversion frequency than its wild-type parent when plotted on the basis of mutation frequency versus survival. However for the E. coli B/r WP2s uvrA strain this higher mutability has been observed only at survival levels of 80-100%. A study was undertaken to determine if these differences in UV mutability were due primarily to the uvrA and uvrB mutations, or to other genetic background differences. Isogenic strains of E. coli K-12 W3110 carrying uvrA6, uvrB5, uvrA6 and uvrB5, and the uvrA allele from E.coli B/r WP2s were used. Results indicate that the enrichment of minimal medium with a small amount of nutrient broth is sufficient to inhibit minimal medium recovery (MMR) and to enhance leu + reversion of the leu B missense mutation in these uvr - strains. This suggests that there may be a relationship between MMR and error-free postreplication repair. Further research is in progress to clarify the relationship between MMR and broth enhancement of UV-induced mutagenesis in uvr - strains of E. Coli K-12 W3110. (author)

  6. Ultraviolet radiation-induced mutability of isogenic uvrA and uvrB strains of Escherichia coli K-12 W3110

    Energy Technology Data Exchange (ETDEWEB)

    Barfknecht, T R; Smith, K C [Stanford Univ., Calif. (USA). Dept. of Radiology

    1977-12-01

    Escherichia coli K-12 W3110 uvrB5 strain has been shown to have a higher uv-induced reversion frequency than its wild-type parent when plotted on the basis of mutation frequency versus survival. However for the E. coli B/r WP2s uvrA strain this higher mutability has been observed only at survival levels of 80 to 100%. A study was undertaken to determine if ly to the uvrA and uvrB mutations, or to other genetic background differences. Isogenic strains of E. coli K-12 W3110 carrying uvrA6, uvrB5, uvrA6, and uvrB5, and the uvrA allele from E.coli B/r WP2s were used. Results indicate that the enrichment of minimal medium with a small amount of nutrient broth is sufficient to inhibit minimal medium recovery (MMR) and to enhance leu/sup +/ reversion of the leu B missense mutation in these uvr/sup -/ strains. This suggests that there may be a relationship between MMR and error-free postreplication repair. Further research is in progress to clarify the relationship between MMR and broth enhancement of uv-induced mutagenesis in uvr/sup -/ strains of E. Coli K-12 W3110.

  7. Persistence of Escherichia coli clones and phenotypic and genotypic antibiotic resistance in recurrent urinary tract infections in childhood

    DEFF Research Database (Denmark)

    Kõljalg, Siiri; Truusalu, Kai; Vainumäe, Inga

    2009-01-01

    . Altogether, 78 urinary E. coli isolates from 27 children, who experienced recurrences during a 1-year follow-up after the first attack of acute pyelonephritis, were investigated. The MICs of sulfamethoxazole, trimethoprim-sulfamethoxazole (SXT), ampicillin, cefuroxime, cefotaxime, and gentamicin...... and the presence or absence of the intI gene for class 1 integrons and the sulfamethoxazole resistance-encoding genes sul1, sul2, and sul3 were determined. All E. coli strains were genotyped by pulsed-field gel electrophoresis. There were no significant differences in the prevalences of resistance to beta...

  8. Population pharmacokinetics and pharmacodynamics of fosfomycin in non-critically ill patients with bacteremic urinary infection caused by multidrug-resistant Escherichia coli.

    Science.gov (United States)

    Merino-Bohórquez, V; Docobo-Pérez, F; Sojo, J; Morales, I; Lupión, C; Martín, D; Cameán, M; Hope, W; Pascual, Á; Rodríguez-Baño, J

    2018-04-10

    To describe the population pharmacokinetics of fosfomycin for patients with bacteraemic urinary tract infection (BUTI). The analysis identified optimal regimens on the basis of pharmacodynamic targets and assessed the adequacy of Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) susceptibility breakpoints for Escherichia coli. Data of 16 patients with BUTI caused by multidrug-resistant E. coli (FOREST clinical trial) received intravenous fosfomycin (4 g every 6 hours) were analysed. A population pharmacokinetic analysis was performed, and Monte Carlo simulations were undertaken using 4 g every 6 hours and 8 g every 8 hours. The probability of pharmacodynamic target attainment was assessed using pharmacodynamic targets for E. coli for static effect, 1-log drop in bacterial burden and resistance suppression. Sixty-four plasma samples were collected over a single dosing interval (day 2 or 3 after starting fosfomycin treatment). Fosfomycin concentrations were highly variable. Pharmacodynamic target attainment analysis showed mild improvement by increasing fosfomycin dosing (4 g every 6 hours vs. every 8 hours). These dosages showed success for decreasing 1-log bacterial burden in 89% to 96% (EUCAST breakpoints) and 33% to 54% (CLSI breakpoints) of patients, but they were unable to reach bacterial resistance suppression targets. Fosfomycin concentrations are highly variable-a fact partially explained by renal impairment. The present work supports the use of 4 g every 6 hours as an effective regimen for the treatment of non-critically ill patients with BUTI caused by multidrug-resistant E. coli, as higher dosages might increase toxicity but may not significantly increase efficacy. The current information may suggest that fosfomycin susceptibility breakpoints need to be reappraised. Copyright © 2018 European Society of Clinical Microbiology and Infectious Diseases. Published by

  9. Efficacy of non-carbapenem antibiotics for pediatric patients with first febrile urinary tract infection due to extended-spectrum beta-lactamase-producing Escherichia coli.

    Science.gov (United States)

    Abe, Yoshifusa; Inan-Erdogan, Işil; Fukuchi, Kunihiko; Wakabayashi, Hitomi; Ogawa, Yasuha; Hibino, Satoshi; Sakurai, Shunsuke; Matsuhashi, Kazuhiko; Watanabe, Yoshitaka; Hashimoto, Kaori; Ugajin, Kazuhisa; Itabashi, Kazuo

    2017-08-01

    Although carbapenem is the recommended for urinary tract infection (UTI) caused by extended-spectrum beta-lactamase (ESBL)-producing organisms, non-carbapenems have been reported to be effective for adult patients with UTI caused by ESBL-producing organisms. The purpose of this study was to evaluate the efficacy of non-carbapenems for pediatric patients with UTI due to ESBL-producing Escherichia coli (E. coli) based on the microbiologic and clinical outcomes. Fifteen children, who were treated for first febrile UTI caused by ESBL-producing E. coli were enrolled in this study. Antimicrobial susceptibilities and ESBL production were determined according to the Clinical and Laboratory Standards Institute guidelines. To detect CTX-M genes, polymerase chain reaction was performed with specific primers for bla CTX-M detection. Of the 15 enrolled patients, 10 (66.7%) were boys and 5 (33.3%) were girls, with a median age of four months. VUR was detected in six patients (40%). For detection of bla CTX-M by PCR, CTX-M-3, CTX-M-8, CTX-M-14, and CTX-M-15 were detected in five, one, eight, and one patient, respectively. Overall, 14 of the 15 isolates (93.3%) were susceptible for fosfomycin (FOM), and all isolates were susceptible for cefmetazole (CMZ), flomoxef (FMOX), and imipenem/cilastatin (IPM/CS). Of the 15 patients, 12 (80%) clinically improved without the use of carbapenems. In conclusion, even if isolates of ESBL-producing E. coli are multidrug resistant based on MIC assessment, clinical susceptibility to non-carbapenems, such as CMZ, FMOX, and FOM, is possible. Accordingly, carbapenems may not be required all the time for treatment of pediatric UTI in clinical practice. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  10. Bipyridine (2,2′-dipyridyl) potentiates Escherichia coli lethality induced by nitrogen mustard mechlorethamine

    International Nuclear Information System (INIS)

    De Alencar, T.A.M.; Wilmart-Gonçalves, T.C.; Vidal, L.S.; Fortunato, R.S.; Leitão, A.C.; Lage, C.

    2014-01-01

    Highlights: • Reduction of Fe 2+ ensues a respiratory burst to reduce the oxidized iron pool. • Through Harber–Weiss recycling, superoxide electrons can reduce oxidized iron. • Redox imbalance sensitized repair proficient Escherichia coli to mustard lethal crosslinks. • A stronger synergism impacted survival of a superoxide dismutase-deficient strain. • Anti-cancer cocktails added of an iron chelator may impact hypoxia and genotoxicity. - Abstract: Alkylating agents are used in anti-tumor chemotherapy because they bind covalently to DNA and generate adducts that may lead to cell death. Bifunctional (HN2) and monofunctional (HN1) nitrogen are two such agents, and HN2 was the first drug successfully employed in anti-leukemia chemotherapy. Currently, HN2 is used either alone or combined with other drugs to treat Hodgkin's disease. It is well known that several crosslinking agents require metabolic activation via reactive oxygen species (ROS) to exert their lethal effects. The objective of this work was therefore to determine whether the abovementioned mustards would also require metabolic activation to exert lethal action against Escherichia coli. For this purpose, we measured survival following exposure to HN2 in E. coli strains that were deficient in nucleotide excision repair (uvrA NER mutant), base excision repair (xthA nfo nth fpg BER mutant) or superoxide dismutase (sodAB mutant) activity. We also performed the same experiments in cells pretreated with an iron chelator (2,2′-dipyridyl, DIP). The NER and BER mutants were only sensitive to HN2 treatment (survival rates similar to those of the wild-type were achieved with 5-fold lower HN2 doses). However, wild-type and sodAB strains were not sensitive to treatment with HN2. In all tested strains, survival dropped by 2.5-fold following pretreatment with DIP compared to treatment with HN2 alone. Furthermore, DIP treatment increased ROS generation in both wild type and sodAB-deficient strains. Based

  11. Bipyridine (2,2′-dipyridyl) potentiates Escherichia coli lethality induced by nitrogen mustard mechlorethamine

    Energy Technology Data Exchange (ETDEWEB)

    De Alencar, T.A.M.; Wilmart-Gonçalves, T.C.; Vidal, L.S.; Fortunato, R.S.; Leitão, A.C. [Laboratório de Radiobiologia Molecular (Brazil); Lage, C., E-mail: claudia_lage_dna@yahoo.com.br [Laboratório de Radiações em Biologia (Brazil)

    2014-07-15

    Highlights: • Reduction of Fe{sup 2+} ensues a respiratory burst to reduce the oxidized iron pool. • Through Harber–Weiss recycling, superoxide electrons can reduce oxidized iron. • Redox imbalance sensitized repair proficient Escherichia coli to mustard lethal crosslinks. • A stronger synergism impacted survival of a superoxide dismutase-deficient strain. • Anti-cancer cocktails added of an iron chelator may impact hypoxia and genotoxicity. - Abstract: Alkylating agents are used in anti-tumor chemotherapy because they bind covalently to DNA and generate adducts that may lead to cell death. Bifunctional (HN2) and monofunctional (HN1) nitrogen are two such agents, and HN2 was the first drug successfully employed in anti-leukemia chemotherapy. Currently, HN2 is used either alone or combined with other drugs to treat Hodgkin's disease. It is well known that several crosslinking agents require metabolic activation via reactive oxygen species (ROS) to exert their lethal effects. The objective of this work was therefore to determine whether the abovementioned mustards would also require metabolic activation to exert lethal action against Escherichia coli. For this purpose, we measured survival following exposure to HN2 in E. coli strains that were deficient in nucleotide excision repair (uvrA NER mutant), base excision repair (xthA nfo nth fpg BER mutant) or superoxide dismutase (sodAB mutant) activity. We also performed the same experiments in cells pretreated with an iron chelator (2,2′-dipyridyl, DIP). The NER and BER mutants were only sensitive to HN2 treatment (survival rates similar to those of the wild-type were achieved with 5-fold lower HN2 doses). However, wild-type and sodAB strains were not sensitive to treatment with HN2. In all tested strains, survival dropped by 2.5-fold following pretreatment with DIP compared to treatment with HN2 alone. Furthermore, DIP treatment increased ROS generation in both wild type and sodAB-deficient strains

  12. An outbreak of enterotoxigenic Escherichia coli (ETEC) infection in Norway, 2012: a reminder to consider uncommon pathogens in outbreaks involving imported products.

    Science.gov (United States)

    MacDonald, E; Møller, K E; Wester, A L; Dahle, U R; Hermansen, N O; Jenum, P A; Thoresen, L; Vold, L

    2015-02-01

    We investigated an outbreak of gastroenteritis following a Christmas buffet served on 4-9 December 2012 to ~1300 hotel guests. More than 300 people were reported ill in initial interviews with hotel guests. To identify possible sources of infection we conducted a cohort investigation through which we identified 214 probable cases. Illness was associated with consumption of scrambled eggs (odds ratio 9·07, 95% confidence interval 5·20-15·84). Imported chives added fresh to the scrambled eggs were the suspected source of the outbreak but were unavailable for testing. Enterotoxigenic Escherichia coli (ETEC) infection was eventually confirmed in 40 hotel guests. This outbreak reinforces that ETEC should be considered in non-endemic countries when the clinical picture is consistent and common gastrointestinal pathogens are not found. Following this outbreak, the Norwegian Food Safety Authority recommended that imported fresh herbs should be heat-treated before use in commercial kitchens.

  13. Effects of dietary additives (potassium diformate/organic acids) as well as influences of grinding intensity (coarse/fine) of diets for weaned piglets experimentally infected with Salmonella Derby or Escherichia coli.

    Science.gov (United States)

    Taube, V A; Neu, M E; Hassan, Y; Verspohl, J; Beyerbach, M; Kamphues, J

    2009-06-01

    The aim of this study was to examine whether and to what extent the addition of potassium diformate (pdf) or free organic acids (fpa) to the diet and the grinding intensity might affect the course of infection and the passage of orally applied Salmonella and Escherichia coli in pigs. Experiments were carried out using 80 reared piglets allotted to four groups. Pigs were fed pelleted diets ad libitum (except during a 15 h feed-withholding-period before infection). The control diet contained finely ground cereals (2 mm screen). To two test diets (also finely ground) 1.2% pdf, 0.9% organic acids (75% formic and 25% propionic acid, fpa) respectively were added. The fourth diet (without acids) was based on coarsely ground cereals (6-mm screen). After experimental infection alternately with S. Derby or E. coli, the course of infection was examined (rectal swab technique). Pigs were sacrificed 4-5 h after a further oral application of approximately 10(9)-10(10) CFU S. Derby or E. coli to determine the counts of Salmonella or E. coli in chyme (classical culture methods). Adding pdf or fpa to the diet led to reduced Salmonella shedding and resulted in significantly lower counts of Salmonella and E. coli in the stomach content indicating an improved efficacy of the stomach barrier. In the distal parts of the digestive tract, the effect was less obvious concerning counts of E. coli, whereas counts of Salmonella were reduced markedly as well. The diet based on coarsely ground cereals failed to demonstrate positive effects concerning infection and passage of orally applied bacteria as well, but this diet was also pelleted and showed unintentionally, comparable amounts of fine particles. Results obtained in this study allow the recommendation of using pdf or organic acids as additives when dietary measures against Salmonella or E. coli in pigs are required.

  14. Colistin- and Carbapenem-Resistant Escherichia coli Harboring mcr-1 and blaNDM-5, Causing a Complicated Urinary Tract Infection in a Patient from the United States.

    Science.gov (United States)

    Mediavilla, José R; Patrawalla, Amee; Chen, Liang; Chavda, Kalyan D; Mathema, Barun; Vinnard, Christopher; Dever, Lisa L; Kreiswirth, Barry N

    2016-08-30

    Colistin is increasingly used as an antibiotic of last resort for the treatment of carbapenem-resistant Gram-negative infections. The plasmid-borne colistin resistance gene mcr-1 was initially identified in animal and clinical samples from China and subsequently reported worldwide, including in the United States. Of particular concern is the spread of mcr-1 into carbapenem-resistant bacteria, thereby creating strains that approach pan-resistance. While several reports of mcr-1 have involved carbapenem-resistant strains, no such isolates have been described in the United States. Here, we report the isolation and identification of an Escherichia coli strain harboring both mcr-1 and carbapenemase gene blaNDM-5 from a urine sample in a patient without recent travel outside the United States. The isolate exhibited resistance to both colistin and carbapenems, but was susceptible to amikacin, aztreonam, gentamicin, nitrofurantoin, tigecycline, and trimethoprim-sulfamethoxazole. The mcr-1- and blaNDM-5-harboring plasmids were completely sequenced and shown to be highly similar to plasmids previously reported from China. The strain in this report was first isolated in August 2014, highlighting an earlier presence of mcr-1 within the United States than previously recognized. Colistin has become the last line of defense for the treatment of infections caused by Gram-negative bacteria resistant to multiple classes of antibiotics, in particular carbapenem-resistant Enterobacteriaceae (CRE). Resistance to colistin, encoded by the plasmid-borne gene mcr-1, was first identified in animal and clinical samples from China in November 2015 and has subsequently been reported from numerous other countries. In April 2016, mcr-1 was identified in a carbapenem-susceptible Escherichia coli strain from a clinical sample in the United States, followed by a second report from a carbapenem-susceptible E. coli strain originally isolated in May 2015. We report the isolation and identification of

  15. Endogenous CO2 may inhibit bacterial growth and induce virulence gene expression in enteropathogenic Escherichia coli.

    Science.gov (United States)

    Martínez, Haydee; Buhse, Thomas; Rivera, Marco; Parmananda, P; Ayala, Guadalupe; Sánchez, Joaquín

    2012-07-01

    Analysis of the growth kinetics of enteropathogenic Escherichia coli (EPEC) revealed that growth was directly proportional to the ratio between the exposed surface area and the liquid culture volume (SA/V). It was hypothesized that this bacterial behavior was caused by the accumulation of an endogenous volatile growth inhibitor metabolite whose escape from the medium directly depended on the SA/V. The results of this work support the theory that an inhibitor is produced and indicate that it is CO(2). We also report that concomitant to the accumulation of CO(2), there is secretion of the virulence-related EspB and EspC proteins from EPEC. We therefore postulate that endogenous CO(2) may have an effect on both bacterial growth and virulence. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Choosing the correct empirical antibiotic for urinary tract infection in pediatric: Surveillance of antimicrobial susceptibility pattern of Escherichia coli by E-Test method.

    Science.gov (United States)

    Sedighi, Iraj; Solgi, Abbas; Amanati, Ali; Alikhani, Mohammad Yousef

    2014-12-01

    Urinary Tract Infections (UTIs) are of the most common bacterial diseases worldwide. We investigate the antibiotic susceptibility patterns of Escherichia coli (E. coli) strains isolated from pediatric patients with community acquired urinary tract infection (UTI) to find a clinical guidance for choosing a right empirical antibiotic in these patients. In this cross sectional study, 100 urine specimens which were positive for E. coli had been investigated for antibiotics susceptibility pattern. The susceptibility to Co-trimoxazol (25μg), Amikacin (30μg), Ceftriaxone (30μg), Nalidixic Acid (30μg), Cefixime (5μg), and Nitrofurantoin (300μg) tested with Disk diffusion agar and MIC determined with the E-test. Mean age of patients was 38 Months. Girls had greater proportion than boys (74 versus 26%). In Disk diffusion method, 26% of the isolates were susceptible to cotrimoxazole. Susceptibility to amikacin, ceftriaxone, nitrofurantoin, nalidixic acid and cefixime was 94%, 66%, 97%, 62% and 52%, respectively. By E-Test method and according to CLSI criteria susceptibility for co-trimoxazol, amikacin, ceftriaxone and nalidixic acid was 37%, 97%, 67% and 50%, respectively. The highest percentage of agreement between Disk diffusion and E-Test method was found for amikacin (96%) and the lowest percentage for co-trimoxazole (89%). Treatment failure, prolonged or repeated hospitalization, increased costs of care, and increased mortality are some consequence of bacterial resistance in UTIs. Misuse of antibiotics in each geographic location directly affects antibiotic resistance pattern. In the treatment of UTI, proper selection of antimicrobial agents should be relevant to the bacterial susceptibility testing surveillance. According to our results, amikacin as an injectable drug and nitrofurantoin as an oral agent could be used as a drug of choice in our region for children with UTIs.

  17. Characterization, Genome Sequence, and Analysis of Escherichia Phage CICC 80001, a Bacteriophage Infecting an Efficient L-Aspartic Acid Producing Escherichia coli.

    Science.gov (United States)

    Xu, Youqiang; Ma, Yuyue; Yao, Su; Jiang, Zengyan; Pei, Jiangsen; Cheng, Chi

    2016-03-01

    Escherichia phage CICC 80001 was isolated from the bacteriophage contaminated medium of an Escherichia coli strain HY-05C (CICC 11022S) which could produce L-aspartic acid. The phage had a head diameter of 45-50 nm and a tail of about 10 nm. The one-step growth curve showed a latent period of 10 min and a rise period of about 20 min. The average burst size was about 198 phage particles per infected cell. Tests were conducted on the plaques, multiplicity of infection, and host range. The genome of CICC 80001 was sequenced with a length of 38,810 bp, and annotated. The key proteins leading to host-cell lysis were phylogenetically analyzed. One protein belonged to class II holin, and the other two belonged to the endopeptidase family and N-acetylmuramoyl-L-alanine amidase family, respectively. The genome showed the sequence identity of 82.7% with that of Enterobacteria phage T7, and carried ten unique open reading frames. The bacteriophage resistant E. coli strain designated CICC 11021S was breeding and its L-aspartase activity was 84.4% of that of CICC 11022S.

  18. Vaccination with Eimeria tenella elongation factor-1α recombinant protein induces protective immunity against E. tenella and E. maxima infections.

    Science.gov (United States)

    Lin, Rui-Qing; Lillehoj, Hyun S; Lee, Seung Kyoo; Oh, Sungtaek; Panebra, Alfredo; Lillehoj, Erik P

    2017-08-30

    Avian coccidiosis is caused by multiple species of the apicomplexan protozoan, Eimeria, and is one of the most economically devastating enteric diseases for the poultry industry worldwide. Host immunity to Eimeria infection, however, is relatively species-specific. The ability to immunize chickens against different species of Eimeria using a single vaccine will have a major beneficial impact on commercial poultry production. In this paper, we describe the molecular cloning, purification, and vaccination efficacy of a novel Eimeria vaccine candidate, elongation factor-1α (EF-1α). One day-old broiler chickens were given two subcutaneous immunizations one week apart with E. coli-expressed E. tenella recombinant (r)EF-1α protein and evaluated for protection against challenge infection with E. tenella or E. maxima. rEF-1α-vaccinated chickens exhibited increased body weight gains, decreased fecal oocyst output, and greater serum anti-EF-1α antibody levels following challenge infection with either E. tenella or E. maxima compared with unimmunized controls. Vaccination with EF-1α may represent a new approach to inducing cross-protective immunity against avian coccidiosis in the field. Published by Elsevier B.V.

  19. Bacterial growth during the early phase of infection determines the severity of experimental Escherichia coli mastitis in dairy cows

    NARCIS (Netherlands)

    Kornalijnslijper, J.E.; Daemen, A.; Werven, van T.; Niewold, T.A.; Rutten, V.; Noordhuizen-Stassen, E.N.

    2004-01-01

    The aim of this study was to investigate the importance of bacterial growth for the severity of experimental Escherichia coli mastitis, indirectly expressed as the area under the curve of bacterial counts in milk over time. The association of pre-infusion somatic cell count and post-infusion influx

  20. Molecular Characterization and Antimicrobial Susceptibility Testing of Escherichia coli Isolates from Patients with Urinary Tract Infections in 20 Chinese Hospitals

    DEFF Research Database (Denmark)

    Cao, Xiaoli; Cavaco, Lina; Lv, Yuan

    2011-01-01

    A total of 222 urinary Escherichia coli isolates from 20 tertiary hospitals in 15 different provinces and 4 municipalities in mainland China were characterized by antimicrobial susceptibility, phylogrouping, and the presence of plasmid-mediated quinolone resistance genes. A subset of 138 suspected...

  1. Why infection-induced anorexia? The case for enhanced apoptosis of infected cells.

    Science.gov (United States)

    LeGrand, E K

    2000-04-01

    A medically important paradox is why the body's own cytokines lead to reduced appetite and apparently inefficient metabolism as part of the acute-phase response. This self-induced nutrient restriction occurs just when the body must maintain a fever and other defensive functions. This paradox is often ignored or considered a metabolic derangement. Others, recognizing it to be a programmed response which must have net beneficial effects, consider the nutrient restriction to be an attempt to deny resources to infectious organisms. However, this explanation fails to address how the pathogen can be harmed more than the host. The hypothesis presented here offers an explanation. Apoptosis, or cell suicide, is becoming recognized as a useful defense against intracellular parasites, and nutrient restriction promotes apoptosis. Thus, nutrient restriction may encourage apoptosis of infected cells. Nutrient restriction can thereby offer protection by simultaneously limiting nutrients to both the host cells and the infectious organisms. Copyright 2000 Harcourt Publishers Ltd.

  2. Probiotic Mixture Golden Bifido Prevents Neonatal Escherichia coli K1 Translocation via Enhancing Intestinal Defense

    Directory of Open Access Journals (Sweden)

    Qing Zeng

    2017-09-01

    Full Text Available Escherichia coli (E. coli K1 sepsis and meningitis is a severe infection characterized by high mortality in neonates. Successful colonization and translocation across the intestinal mucosa have been regarded as the critical steps for E. coli K1 sepsis and meningitis. We recently reported that the probiotic mixture, Golden Bifido (containing live Lactobacillus bulgaricus, Bifidobacterium, and Streptococcus thermophilus, LBS has a preventive role against neonatal E. coli K1 bacteremia and meningitis. However, the interaction between the neonatal gut barrier, probiotics and E. coli K1 is still not elucidated. The present study aims to investigate how LBS exerts its protective effects on neonatal gut barrier during E. coli K1 infection. The beneficial effects of LBS were explored in vitro and in vivo using human colon carcinoma cell lines HT-29 and rat model of neonatal E. coli K1 infection, respectively. Our results showed that stimulation with E. coli K1 was able to cause intestinal barrier dysfunction, which were reflected by E. coli K1-induced intestinal damage and apoptosis of intestinal epithelial cells, reduction of mucin, immunoglobulin A (IgA and tight junction proteins expression, as well as increase in intestinal permeability, all these changes facilitate E. coli K1 intestinal translocation. However, these changes were alleviated when HT-29 cells were treated with LBS before E. coli K1 infection. Furthermore, we found that LBS-treated neonatal rats (without E. coli K1 infection have showed higher production of mucin, ZO-1, IgA, Ki67 in intestinal mucosa as well as lower intestinal permeability than that of non-treated rats, indicating that LBS could accelerate the development of neonatal intestinal defense. Taken together, our results suggest that enhancement of the neonatal intestinal defense to fight against E. coli K1 translocation could be the potential mechanism to elucidate how LBS confers a protective effect against neonatal E

  3. Enhanced protection against Clonorchis sinensis induced by co-infection with Trichinella spiralis in rats.

    Science.gov (United States)

    Chu, K-B; Kim, S-S; Lee, S-H; Lee, H-S; Joo, K-H; Lee, J-H; Lee, Y-S; Zheng, S; Quan, F-S

    2014-10-01

    Although co-infection with multiple parasites is a frequent occurrence, changes in the humoral immune response against a pre-existing parasite induced as a result of a subsequent parasitic infection remain undetermined. Here, we utilized enzyme-linked immunosorbent assay (ELISA) to investigate antibody responses, cytokine production and enhanced resistance in Clonorchis sinensis-infected rats (Sprague-Dawley) upon Trichinella spiralis infection. Higher levels of C. sinensis-specific IgG and IgA were elicited upon T. spiralis infection, and these levels remained higher than in rats infected with C. sinensis alone. Upon subsequent infection with T. spiralis, IgG antibodies against C. sinensis appeared to be rapidly boosted at day 3, and IgA antibodies were boosted at day 7. Challenge infection of C. sinensis-infected rats with T. spiralis induced substantial mucosal IgG and IgA responses in the liver and intestine and increases in antibody-secreting plasma cells in the spleen and bone marrow. Subsequent infection also appeared to confer effective control of liver C. sinensis loads, resulting in enhanced resistance. Memory B cells generated in response to C. sinensis infection were rapidly amplified into antibody-secreting cells upon T. spiralis infection. These results indicate that enhanced C. sinensis clearance induced by co-infection is associated with systemic and mucosal IgG and IgA responses. © 2014 John Wiley & Sons Ltd.

  4. Characterization of Escherichia coli Phylogenetic Groups ...

    African Journals Online (AJOL)

    tract infection (UTI), bacteremia, pneumonia, soft-tissue infection, and ... Keywords: Drug resistance, Escherichia coli, Extraintestinal infections, Polymerase chain reaction, .... gynecology, 12 from orthopedics and 5 from pediatrics units.

  5. Draft genome sequences of three Escherichia coli strains with different In Vivo pathogenicities in an avian (Ascending) infection model of the oviduct

    DEFF Research Database (Denmark)

    Olsen, Rikke Heidemann; Thøfner, Ida; Pors, Susanne Elisabeth

    2015-01-01

    Here, we present three draft genome sequences of Escherichia coli strains that experimentally were proven to possess low (strain D2-2), intermediate (Chronic_salp), or high virulence (Cp6salp3) in an avian (ascending) infection model of the oviduct.......Here, we present three draft genome sequences of Escherichia coli strains that experimentally were proven to possess low (strain D2-2), intermediate (Chronic_salp), or high virulence (Cp6salp3) in an avian (ascending) infection model of the oviduct....

  6. Effect of stress induced by suboptimal growth factors on survival of Escherichia coli O157:H7.

    Science.gov (United States)

    Uyttendaele, M; Taverniers, I; Debevere, J

    2001-05-21

    This study investigated the growth and survival of E. coli O157:H7 exposed to a combination of suboptimal factors (22 degrees C, 7 degrees C, -18 degrees C/0.5% NaCl, 5.0% NaCl/pH 7.0, pH 5.4, pH 4.5/addition of lactic acid) in a simulation medium for red meat (beef gravy). Prolonged survival was noted as the imposed stress was more severe, and as multiple growth factors became suboptimal. At a defined temperature (7 degrees C or -18 degrees C), survival was prolonged at the more acid, more suboptimal pH (pH 4.5 > pH 5.4 > pH 7.0) while at a defined pH (pH 4.5), better survival was observed at 7 degrees C than at 22 degrees C. This suggests that application of the hurdle concept for preservation of food may inhibit outgrowth but induce prolonged survival of E. coli O157:H7 in minimal processed foods. At both 22 degrees C and 7 degrees C, the addition of lactic acid instead of HCl to reduce pH (to pH 4.5) resulted in a more rapid decrease of E. coli O157:H7. High survival was observed in beef gravy, pH 5.4 at -18 degrees C (simulation of frozen meat)-reduction of log 3.0 to log 1.9 after 43 days--and in beef gravy, pH 4.5 and 5% NaCl at 7 degrees C (simulation of a fermented dried meat product kept in refrigeration)--less than 1 log reduction in 43 days. In these circumstances, however, a high degree of sublethal damage of the bacterial cells was noted. The degree of sublethal damage can be estimated from the difference in recovery of the pathogen on the non-selective TSA medium and the selective SMAC medium.

  7. 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...

  8. Lactobacillus acidophilus induces a slow but more sustained chemokine and cytokine response in naïve foetal enterocytes compared to commensal Escherichia coli

    Directory of Open Access Journals (Sweden)

    Nellemann Christine

    2010-01-01

    Full Text Available Abstract Background The first exposure to microorganisms at mucosal surfaces is critical for immune maturation and gut health. Facultative anaerobic bacteria are the first to colonise the infant gut, and the impact of these bacteria on intestinal epithelial cells (IEC may be determinant for how the immune system subsequently tolerates gut bacteria. Results To mirror the influence of the very first bacterial stimuli on infant IEC, we isolated IEC from mouse foetuses at gestational day 19 and from germfree neonates. IEC were stimulated with gut-derived bacteria, Gram-negative Escherichia coli Nissle and Gram-positive Lactobacillus acidophilus NCFM, and expression of genes important for immune regulation was measured together with cytokine production. E. coli Nissle and L. acidophilus NCFM strongly induced chemokines and cytokines, but with different kinetics, and only E. coli Nissle induced down-regulation of Toll-like receptor 4 and up-regulation of Toll-like receptor 2. The sensitivity to stimulation was similar before and after birth in germ-free IEC, although Toll-like receptor 2 expression was higher before birth than immediately after. Conclusions In conclusion, IEC isolated before gut colonisation occurs at birth, are highly responsive to stimulation with gut commensals, with L. acidophilus NCFM inducing a slower, but more sustained response than E. coli Nissle. E. coli may induce intestinal tolerance through very rapid up-regulation of chemokine and cytokine genes and down-regulation of Toll-like receptor 4, while regulating also responsiveness to Gram-positive bacteria.

  9. Mutagenic potency of MMS-induced 1meA/3meC lesions in E. coli.

    Science.gov (United States)

    Nieminuszczy, Jadwiga; Mielecki, Damian; Sikora, Anna; Wrzesiński, Michał; Chojnacka, Aleksandra; Krwawicz, Joanna; Janion, Celina; Grzesiuk, Elzbieta

    2009-12-01

    The mutagenic activity of MMS in E. coli depends on the susceptibility of DNA bases to methylation and their repair by cellular defense systems. Among the lesions in methylated DNA is 1meA/3meC, which is recently recognized as being mutagenic. In this report, special attention is focused on the mutagenic properties of 1meA/3meC which, by the activity of AlkB-dioxygenase, are quickly and efficiently converted to natural A/C bases in the DNA of E. coli alkB(+) strains, preventing 1meA/3meC-induced mutations. We have found that in the absence of AlkB-mediated repair, MMS treatment results in an increased frequency of four types of base substitutions: GC-->CG, GC-->TA, AT-->CG, and AT-->TA, whereas overproduction of PolV in CC101-106 alkB(-)/pRW134 strains leads to a markedly elevated level of GC-->TA, GC-->CG, and AT-->TA transversions. It has been observed that in the case of AB1157 alkB(-) strains, the MMS-induced and 1meA/3meC-dependent argE3-->Arg(+) reversion occurs efficiently, whereas lacZ(-)--> Lac(+) reversion in a set of CC101-106 alkB(-) strains occurs with much lower frequency. We considered several reasons for this discrepancy, namely, the possible variance in the level of the PolV activity, the effect of the PolIV contents that is higher in CC101-106 than in AB1157 strains and the different genetic cell backgrounds in CC101-106 alkB(-) and AB1157 alkB(-) strains, respectively. We postulate that the difference in the number of targets undergoing mutation and different reactivity of MMS with ssDNA and dsDNA are responsible for the high (argE3-->Arg(+)) and low (lacZ(-) --> Lac(+)) frequency of MMS-induced mutations.

  10. Damage to E. coli cells induced by tritium decay: secondary lethality under nongrowth conditions

    International Nuclear Information System (INIS)

    Koukalova, B.; Kuhrova, V.

    1980-01-01

    Cells containing incorporated 3 H-thymidine are damaged by its decay. It was found with E.coli TAU-bar cells that a small part of the damage is lethal whereas most of it is reparable and only potentially lethal. If cells are subjected to nongrowth conditions, the potentially lethal damage changes to lethal damage. This process is called secondary lethality (SL). The extent of SL and some changes in DNA under three different modes of growth inhibition were determined. It was found that: (i) SL is maximal under conditions of amino acid starvation (-AA), the viable count decreasing by two orders of magnitude. (ii) SL is 4 times lower in the presence of chloramphenicol (-AA+CLP) and 6.5 times lower under +AA+CLP conditions. Changes in the sedimentation rate of DNA determined in alkaline sucrose gradient correlate with the differences in SL: under -AA conditions the sedimentation rate of DNA decreases whereas in the presence of CLP no decrease occurs. The results suggest that certain enzymatic processes take place under -AA conditions which lead to irreparable changes in DNA. (author)

  11. Repair of damage induced by ultraviolet radiation in mutator T-1 Escherichia coli transductants

    International Nuclear Information System (INIS)

    Sideropoulos, A.S.; Greenberg, J.; Warren, G.

    1975-01-01

    To ascertain whether a relationship commonly exists between azide resistance, ultraviolet (uv) resistance, and the mutator property (mut T-1), we performed uv survival and mutation frequency determinations with and without caffeine (2.571 mM) in nonmutator azide resistant (azi/sup r/) and phage mediated mut T-1 transductants of Escherichia coli K-12, B/r, B/r T-, Bs-1, and Bs-8. The strains constructed were assumed to be ''co-isogenic'' except for the mutator factor. The frequency of mutation to streptomycin resistance (str/sup r/) was relatively constant and approximated 2 x 10- 7 . Transductants carrying the azide marker with or without the mut T-1 gene had the same level of uv survival as the parent with the same mutator phenotype. Dark repair of the prelethal uv lesion is equally caffeine sensitive in the nonmutator and mutator HCR+ strains. Our results indicated that the mut T-1 strains possess an efficient dark repair system for uv damage and that the mechanism of mut T-1 action is independent of uv dark repair processes. (auth)

  12. Damage to E. coli cells induced by tritium decay: secondary lethality under nongrowth conditions

    Energy Technology Data Exchange (ETDEWEB)

    Koukalova, B; Kuhrova, V [Ceskoslovenska Akademie Ved, Brno. Biofysikalni Ustav

    1980-05-01

    Cells containing incorporated /sup 3/H-thymidine are damaged by its decay. It was found with E.coli TAU-bar cells that a small part of the damage is lethal whereas most of it is reparable and only potentially lethal. If cells are subjected to nongrowth conditions, the potentially lethal damage changes to lethal damage. This process is called secondary lethality (SL). The extent of SL and some changes in DNA under three different modes of growth inhibition were determined. It was found that: (i) SL is maximal under conditions of amino acid starvation (-AA), the viable count decreasing by two orders of magnitude. (ii) SL is 4 times lower in the presence of chloramphenicol (-AA+CLP) and 6.5 times lower under +AA+CLP conditions. Changes in the sedimentation rate of DNA determined in alkaline sucrose gradient correlate with the differences in SL: under -AA conditions the sedimentation rate of DNA decreases whereas in the presence of CLP no decrease occurs. The results suggest that certain enzymatic processes take place under -AA conditions which lead to irreparable changes in DNA.

  13. Single-cell, real-time detection of oxidative stress induced in Escherichia coli by the antimicrobial peptide CM15.

    Science.gov (United States)

    Choi, Heejun; Yang, Zhilin; Weisshaar, James C

    2015-01-20

    Antibiotics target specific biochemical mechanisms in bacteria. In response to new drugs, pathogenic bacteria rapidly develop resistance. In contrast, antimicrobial peptides (AMPs) have retained broad spectrum antibacterial potency over millions of years. We present single-cell fluorescence assays that detect reactive oxygen species (ROS) in the Escherichia coli cytoplasm in real time. Within 30 s of permeabilization of the cytoplasmic membrane by the cationic AMP CM15 [combining residues 1-7 of cecropin A (from moth) with residues 2-9 of melittin (bee venom)], three fluorescence signals report oxidative stress in the cytoplasm, apparently involving O2 (-), H2O2, and •OH. Mechanistic studies indicate that active respiration is a prerequisite to the CM15-induced oxidative damage. In anaerobic conditions, signals from ROS are greatly diminished and the minimum inhibitory concentration increases 20-fold. Evidently the natural human AMP LL-37 also induces a burst of ROS. Oxidative stress may prove a significant bacteriostatic mechanism for a variety of cationic AMPs. If so, host organisms may use the local oxygen level to modulate AMP potency.

  14. Mutagenic DNA repair in Escherichia coli. Pt. 2. Factors affecting loss of photoreversibility of UV induced mutations

    Energy Technology Data Exchange (ETDEWEB)

    Doubleday, O P; Bridges, B A; Green, M H.L. [Medical Research Council, Brighton (UK). Cell Mutation Unit

    1975-01-01

    The photoreversibility of UV-induced mutations to Trp/sup +/ in strain Escherichia coli WP2 uvr A trp (unable to excise pyrimidine dimers) was lost at different rates during incubation in different media. In Casamino acids medium after a short initial lag, photoreversibility was lost over about one generation time; in minimal medium with tryptophan, photoreversibility persisted for more than two generations; in Casamino acids medium with pantoyl lactone photoreversibility was lost extremely slowly. The rate of loss of photoreversibility was unaffected by UV dose in either Casamino acids medium or in minimal medium. The same eventual number of induced mutants was obtained when cells were incubated for two generations in any of the three media before being transferred to selective plates supplemented with Casamino acids. Thus in each the proportion of cells capable of giving rise to a mutant was the same and only the rate at which these cells did so during post-irradiation growth varied, suggesting that there might be a specific fraction of pyrimidine dimers at a given site capable of initiating a mutagenic repair event, and that the size of this fraction is dose dependent. Segregation experiments have shown that error-prone repair appears to occur once only and is not repeated in subsequent replication cycles, in contrast to (presumed error-free) recombination repair. The results are discussed in the light of current models of UV mutagenesis.

  15. Antibiotic stress-induced modulation of the endoribonucleolytic activity of RNase III and RNase G confers resistance to aminoglycoside antibiotics in Escherichia coli.

    Science.gov (United States)

    Song, Wooseok; Kim, Yong-Hak; Sim, Se-Hoon; Hwang, Soonhye; Lee, Jung-Hyun; Lee, Younghoon; Bae, Jeehyeon; Hwang, Jihwan; Lee, Kangseok

    2014-04-01

    Here, we report a resistance mechanism that is induced through the modulation of 16S ribosomal RNA (rRNA) processing on the exposure of Escherichia coli cells to aminoglycoside antibiotics. We observed decreased expression levels of RNase G associated with increased RNase III activity on rng mRNA in a subgroup of E. coli isolates that transiently acquired resistance to low levels of kanamycin or streptomycin. Analyses of 16S rRNA from the aminoglycoside-resistant E. coli cells, in addition to mutagenesis studies, demonstrated that the accumulation of 16S rRNA precursors containing 3-8 extra nucleotides at the 5' terminus, which results from incomplete processing by RNase G, is responsible for the observed aminoglycoside resistance. Chemical protection, mass spectrometry analysis and cell-free translation assays revealed that the ribosomes from rng-deleted E. coli have decreased binding capacity for, and diminished sensitivity to, streptomycin and neomycin, compared with wild-type cells. It was observed that the deletion of rng had similar effects in Salmonella enterica serovar Typhimurium strain SL1344. Our findings suggest that modulation of the endoribonucleolytic activity of RNase III and RNase G constitutes a previously uncharacterized regulatory pathway for adaptive resistance in E. coli and related gram-negative bacteria to aminoglycoside antibiotics.

  16. UVB-induced immune suppression and infection with Schistosoma mansoni

    International Nuclear Information System (INIS)

    Noonan, F.P.; Lewis, F.A.

    1995-01-01

    Irradiation with ultraviolet B (UVB, 290-320 nm) causes a systematic immunosuppression of cell-mediated immunity. The question of whether UV immunosuppression modulates the course of infectious diseases is important because UVB levels in sunlight are sufficient to predict significant UV-induced immunosuppression at most latitudes. We have investigated the effect of immunosuppressive doses of UVB on the disease caused by the helminth parasite Schistosoma mansoni. C57BL/6 mice were irradiated once or three times weekly over 60-80 days with UV from a bank of FS40 sunlamps. Each UV treatment consisted of an immunosuppressive UV dose, as determined by suppression of contact hypersensitivity to trinitrochlorobenzene, corresponding to about 15-30 min of noonday tropical sunlight exposure under ideal clear sky conditions. Cumulative UV doses were between 80 and 170 kJ/m 2 . Worm and egg burdens, liver granuloma diameters and liver fibrosis showed minimal changes ( 2 administered in six treatments) did not impair the resistance to rechallenge conferred by vaccination with 60 Co-irradiated cercariae. We have observed a dichotomy between UV immnosuppression and both disease and vaccination in this helminth infection, in contrast to the effects of UVB shown in other infectious diseases. (author)

  17. Adherence of Enterohemorrhagic Escherichia coli to Human Epithelial Cells: The Role of Intimin

    Science.gov (United States)

    1995-04-28

    mucosa (e.g., enterotoxigenic E. coli, Vibrio cholerae , and Boroetella pertussis); ii) damage to the epithelial cell microvilli induced by the...diarrhea in Mayan childm in Mexico . J. Infect. Dis. 163, 507-513. G6mez-Ouarte, O.G. and Kaper, J.B. (1995). A plasmid-encoded regulartory region...de la Cabaca, F., and Garibay, E.V. (1987). Enteroadherent Escherichia coli as a cause of diarrhea among children in Mexico . J . Clin. Microbiol. 25

  18. Genetically Engineered Escherichia coli Nissle 1917 Synbiotics Reduce Metabolic Effects Induced by Chronic Consumption of Dietary Fructose.

    Directory of Open Access Journals (Sweden)

    Chaudhari Archana Somabhai

    Full Text Available To assess protective efficacy of genetically modified Escherichia coli Nissle 1917 (EcN on metabolic effects induced by chronic consumption of dietary fructose.EcN was genetically modified with fructose dehydrogenase (fdh gene for conversion of fructose to 5-keto-D-fructose and mannitol-2-dehydrogenase (mtlK gene for conversion to mannitol, a prebiotic. Charles foster rats weighing 150-200 g were fed with 20% fructose in drinking water for two months. Probiotic treatment of EcN (pqq, EcN (pqq-glf-mtlK, EcN (pqq-fdh was given once per week 109 cells for two months. Furthermore, blood and liver parameters for oxidative stress, dyslipidemia and hyperglycemia were estimated. Fecal samples were collected to determine the production of short chain fatty acids and pyrroloquinoline quinone (PQQ production.EcN (pqq-glf-mtlK, EcN (pqq-fdh transformants were confirmed by restriction digestion and functionality was checked by PQQ estimation and HPLC analysis. There was significant increase in body weight, serum glucose, liver injury markers, lipid profile in serum and liver, and decrease in antioxidant enzyme activity in high-fructose-fed rats. However the rats treated with EcN (pqq-glf-mtlK and EcN (pqq-fdh showed significant reduction in lipid peroxidation along with increase in serum and hepatic antioxidant enzyme activities. Restoration of liver injury marker enzymes was also seen. Increase in short chain fatty acids (SCFA demonstrated the prebiotic effects of mannitol and gluconic acid.Our study demonstrated the effectiveness of probiotic EcN producing PQQ and fructose metabolizing enzymes against the fructose induced hepatic steatosis suggesting that its potential for use in treating fructose induced metabolic syndrome.

  19. Shiga toxin-converting phages and the emergence of new pathogenic Escherichia coli: a world in motion

    Science.gov (United States)

    Tozzoli, Rosangela; Grande, Laura; Michelacci, Valeria; Ranieri, Paola; Maugliani, Antonella; Caprioli, Alfredo; Morabito, Stefano

    2014-01-01

    Shiga toxin (Stx)-producing Escherichia coli (STEC) are pathogenic E. coli causing diarrhea, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). STEC are characterized by a constellation of virulence factors additional to Stx and have long been regarded as capable to cause HC and HUS when possessing the ability of inducing the attaching and effacing (A/E) lesion to the enterocyte, although strains isolated from such severe infections sometimes lack this virulence feature. Interestingly, the capability to cause the A/E lesion is shared with another E. coli pathogroup, the Enteropathogenic E. coli (EPEC). In the very recent times, a different type of STEC broke the scene causing a shift in the paradigm for HUS-associated STEC. In 2011, a STEC O104:H4 caused a large outbreak with more than 800 HUS and 50 deaths. Such a strain presented the adhesion determinants of Enteroaggregative E. coli (EAggEC). We investigated the possibility that, besides STEC and EAggEC, other pathogenic E. coli could be susceptible to infection with stx-phages. A panel of stx2-phages obtained from STEC isolated from human disease was used to infect experimentally E. coli strains representing all the known pathogenic types, including both diarrheagenic E. coli (DEC) and extra-intestinal pathogenic E. coli (ExPEC). We observed that all the E. coli pathogroups used in the infection experiments were susceptible to the infection. Our results suggest that the stx2-phages used may not have specificity for E. coli adapted to the intestinal environment, at least in the conditions used. Additionally, we could only observe transient lysogens suggesting that the event of stable stx2-phage acquisition occurs rarely. PMID:24999453

  20. The in vitro synthesis of {beta}-galactosidase induced in a subcellular structure of Escherichia coli (1961); Synthese in vitro de {beta}-galactosidase induite dans une structure subcellulaire d'Escherichia coli (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Nisman, B; Kayser, A; Demailly, J; Genin, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    Isopropyl-thio-galactoside (IPTG), an inducer of 3-galactosidase, makes it possible to synthesise this enzyme in vitro with the subcellular structure (P{sub 1}). The enzyme is isolated from the bacteria Escherichia coli K 12 which are inductive but not induced. The incorporation of radioactive amino-acids, which is stimulated by the presence of an inducer, was studied during the course of the enzyme synthesis. Saccharose suppresses the induction of {beta}-galactosidase. The presence of a specific inhibitor in the structure studied is considered. (authors) [French] L'isopropylthiogalactoside (IPTG), inducteur de la 3-galactosidase, permet la synthese in vitro de cette enzyme dans la structure subcellulaire (P{sub 1}) isolee a partir des bacteries d'Escherichia coli K 12, inductibles mais non induites. L'incorporation d'acides amines radioactifs, stimulee par la presence d'inducteur, a ete etudiee au cours de la synthese de l'enzyme. Le saccharose supprime l'induction de la 3-galactosidase. La presence du represseur specifique dans la structure etudiee est consideree. (auteurs)

  1. Radiolabeling of infective third-stage larvae of Strongyloides stercoralis by feeding [75Se]selenomethionine-labeled Escherichia coli to first- and second-stage larvae

    International Nuclear Information System (INIS)

    Aikens, L.M.; Schad, G.A.

    1989-01-01

    A technique is described for radiolabeling Strongyloides stercoralis larvae with [ 75 Se]selenomethionine. Cultures of an auxotrophic methionine-dependent stain of Escherichia coli were grown in a medium containing Dulbecco's modified Eagle's medium supplemented with 5% nutrient broth, amino acids, and [ 75 Se]selenomethionine. When the 75 Se-labeled bacterial populations were in the stationary phase of growth, cultures were harvested and the bacteria dispersed on agar plates to serve as food for S. stercoralis larvae. Use of nondividing bacteria is important for successful labeling because the isotope is not diluted by cell division and death of larvae attributable to overgrowth by bacteria is prevented. First-stage S. stercoralis larvae were recovered from feces of infected dogs and reared in humid air at 30 C on agar plates seeded with bacteria. After 7 days, infective third-stage larvae were harvested. The mean specific activity of 6 different batches of larvae ranged from 75 to 330 counts per min/larva with 91.8 +/- 9.5% of the population labeled sufficiently to produce an autoradiographic focus during a practicable, 6-wk period of exposure. Labeled infective larvae penetrated the skin of 10-day-old puppies and migrated to the small intestine, where the developed to adulthood

  2. New perspectives to the enterotoxigenic E. coli F4 porcine infection model: Susceptibility genotypes in relation to performance, diarrhoea and bacterial shedding.

    Science.gov (United States)

    Roubos-van den Hil, Petra J; Litjens, Ralph; Oudshoorn, Anna-Katharina; Resink, Jan Willem; Smits, Coen H M

    2017-04-01

    Enterotoxigenic E. coli (ETEC), causing post-weaning diarrhoea, is a major problem in weaned piglets. Individual animal responses to ETEC infection show high variability in animal experiments. Two studies were designed to optimize the ETEC F4ac infection model in piglets by combining the genotype susceptibility with performance, diarrhoea incidence and bacterial shedding. The studies were performed with respectively 120 and 80 male piglets that were tested for susceptibility or resistance towards ETEC O149:F4ac by a DNA marker based test. Three different genotypes were observed; resistant (RR), susceptible heterozygote (RS) and susceptible homozygote (SS). Piglets, were orally infected with an inoculum suspension (containing 1.5E8 CFU/ml ETEC F4ac) at day 0, 1 and 2 of the study. Performance, diarrhoea incidence and bacterial shedding were followed for 21days. In the first week after challenge a difference in average daily gain was observed between resistant and susceptible piglets in both studies. For the complete study period no significant differences were observed. Diarrhoea incidence was significantly higher in susceptible pigs compared to the resistant pigs in the first week after challenge. Bacterial shedding was much higher in the susceptible pigs and ETEC excretion lasted longer. ETEC was hardly detected in the faecal material of the resistant pigs. In conclusion, susceptible pigs showed higher diarrhoea incidence and higher numbers of faecal ETEC shedding in the first week after challenge compared to resistant pigs. The DNA marker based test can be used to select pigs that are susceptible for ETEC for inclusion in ETEC infection model, resulting in less animals needed to perform infection studies. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Hemolytic-uremic syndrome with acute encephalopathy in a pregnant woman infected with epidemic enterohemorrhagic Escherichia coli: characteristic brain images and cytokine profiles.

    Science.gov (United States)

    Ito, M; Shiozaki, A; Shimizu, M; Saito, S

    2015-05-01

    A food-poisoning outbreak due to enterohemorrhagic Escherichia coli (EHEC) occurred in Toyama, Japan. The case of a 26-year-old pregnant woman with hemolytic-uremic syndrome who developed acute encephalopathy due to EHEC infection after eating raw meat is presented herein. On day 2 following admission, a cesarean section was performed because of a non-reassuring fetal status. Fecal bacterial culture confirmed an O111/O157 superinfection. Intensive care therapies including continuous hemodiafiltration and plasma exchange were performed. After the operation, the patient developed encephalopathy for which steroid pulse therapy was added. Her condition improved gradually and she was discharged 55 days after delivery. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. A waterborne outbreak of multiple diarrhoeagenic Escherichia coli infections associated with drinking water at a school camp.

    Science.gov (United States)

    Park, Jungsun; Kim, Jin Seok; Kim, Soojin; Shin, Eunkyung; Oh, Kyung-Hwan; Kim, Yonghoon; Kim, Cheon Hyeon; Hwang, Min Ah; Jin, Chan Mun; Na, Kyoungin; Lee, Jin; Cho, Enhi; Kang, Byung-Hak; Kwak, Hyo-Sun; Seong, Won Keun; Kim, Junyoung

    2018-01-01

    In June 2015, a local public health laboratory was notified that students had developed gastroenteritis symptoms after attending a camp. An outbreak investigation was conducted to determine the extent and cause of the outbreak. A retrospective cohort study was conducted to determine the correlations between the illness and specific exposures at the school camp. All attendees were interviewed with a standard questionnaire that addressed clinical symptoms, food consumption, and environmental exposures. Clinical specimens were cultured using standard microbiological methods for bacterial and viral pathogens. The genetic relationships of all isolates were determined using pulsed-field gel electrophoresis (PFGE). A total 188 patients with symptoms of diarrhoea, abdominal pain, and nausea were identified. The completed questionnaires suggested that the consumption of drinking water was likely to be linked to this outbreak. Using microbiological methods, enterohaemorrhagic Escherichia coli, enteropathogenic E. coli, and enteroaggregative E. coli were isolated, and the isolates from both patient stool and environmental water samples displayed indistinguishable XbaI-PFGE patterns. The water system in the camp used groundwater drawn from a private underground reservoir for cooking and drinking. The environmental investigation revealed some problems with the water supply system, such as the use of inappropriate filters in the water purifier and a defect in the pipeline between the reservoir and the chlorination device. This outbreak points to the importance of drinking water quality management in group facilities where underground water is used and emphasizes the need for periodic sanitation and inspection to prevent possible waterborne outbreaks. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  5. Fatal case of hemolytic-uremic syndrome in an adult due to a rare serogroup O91 Entero hemorrhagic Escherichia coli associated with a Clostridium difficile infection. More than meets the eye

    Directory of Open Access Journals (Sweden)

    Thomas Guillard

    2015-08-01

    Full Text Available Hemolytic-uremic syndrome due to enterohemorrhagic Escherichia coli, belonging to serogroup O91 has rarely been described. We report here a case of post-diarrheal HUS due to EHEC O91 in an elderly patient for whom diagnosis was delayed given a previously diagnosed C. difficile infection. This case highlights the usefulness of Shiga-toxin detection.

  6. Urinary tract infections in pregnancy.

    Science.gov (United States)

    Ovalle, A; Levancini, M

    2001-01-01

    Urinary tract infections are very common during pregnancy. Escherichia coli is the most common pathogen isolated from pregnant women. Ampicillin should not be used because of its high resistance to Escherichia coli. Pyelonephritis can cause morbidity and can be life-threatening to both mother and fetus. Second and third-generation cephalosporins are recommended for treatment, administered initially intravenously during hospitalization. Cultures and the study of virulence factors of uropathogenic Escherichia coli are recommended for the adequate management of pyelonephritis. The lower genital tract infection associated with pyelonephritis is responsible for the failure of antibiotic treatment. Asymptomatic bacteriuria can evolve into cystitis or pyelonephritis. All pregnant women should be routinely screened for bacteriuria using urine culture, and should be treated with nitrofurantoin, sulfixosazole or first-generation cephalosporins. Recurrent urinary infection should be treated with prophylactic antibiotics. Pregnant women who develop urinary tract infections with group B streptococcal infection should be treated with prophylactic antibiotics during labour to prevent neonatal sepsis. Preterm delivery is frequent. Evidence suggests that infection plays a role in the pathogenesis of preterm labour. Experimental models in pregnant mice support the theory that Escherichia coli propagated by the transplacental route, involving bacterial adhesins, induces preterm delivery, but this has not been demonstrated in humans. Ascending lower genital tract infections are the most probable cause of preterm delivery, but this remains to be proved.

  7. Peroxiredoxin 1 protects the pea aphid Acyrthosiphon pisum from oxidative stress induced by Micrococcus luteus infection.

    Science.gov (United States)

    Zhang, Yongdong; Lu, Zhiqiang

    2015-05-01

    Reactive oxygen species (ROSs) are generated in organisms in response to infections caused by invading microbes. However, excessive ROSs will inflict oxidative damage on the host. Peroxiredoxins (Prxs) are antioxidative enzymes that may eliminate ROSs efficiently. In this study, ApPrx1 from the pea aphid Acyrthosiphon pisum was cloned, and its function was investigated in vitro and in vivo. In the presence of DTT, recombinant ApPrx1 protein from Escherichia coli showed antioxidative activity by eliminating H2O2 effectively. The H2O2 levels were significantly higher in Micrococcus luteus-infected aphids than in uninfected aphids, and ApPrx1 expression was remarkably up-regulated when the aphids were infected with M. luteus or injected with H2O2. When ApPrx1 expression was reduced by dsRNA injection, the survival of the aphids decreased significantly after M. luteus infection. Knockdown of ApPrx1 decreased M. luteus loads inside the aphids 48h post-infection. While under infection conditions, the H2O2 levels were much higher in ApPrx1 knockdown aphids than in dsGFP-injected aphids, indicating that the decreased survival of the aphids was caused by increased oxidative stress. Taken together, our results reveal that ApPrx1 plays a protective role in oxidative stress caused by bacterial infection. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. E. Coli

    Science.gov (United States)

    ... for the bacteria's medical name Escherichia coli . The strange thing about these bacteria — and lots of other ... In some cases, E. coli poisoning can cause life-threatening kidney problems. What Can Kids Do? Adults ...

  9. Comparison of Two Different Disk Diffusion Agar Tests in Determination of Antibiotic Susceptibility for E-Coli Isolated from Urinary Tract Infection in Pediatrics

    Directory of Open Access Journals (Sweden)

    I. Sedighi

    2010-04-01

    Full Text Available Introduction & Objective: Urinary Tract Infection (UTI is one of the most common infections during childhood and E-Coli is the more predominant pathogen recovered in UTI. Disk Diffusion agar test is a method of choice because it is cost effective, simple, and now routinely used for detection of antibiotic susceptibility. A rapid increase in antibiotic resistance in our region made the authors to design a study to compare this traditional method with two different disk diffusion agar tests.Materials & Methods: Our study was conducted between 2009 and 2010 in Be’sat teaching hospital on 100 pediatric patients ranged 15 days to 13 years old with positive urine culture for E-coli. Antibiogram detection was performed by disk diffusion agar test with two different kits as Padtan-Teb (made in Iran and Mast (made in the U.K. for Co-trimoxazol, Amikacin, Ceftriaxone, Nalidixic Acid, Cefixime, and Nitrofurantoin. At last the data was analyzed by McNemar test.Results: Co-trimoxazol obtained the lowest (23% Padtan-Teb and 26% Mast and Nitrofurantoin had the highest (86% Padtan-Teb and 97% Mast sensitivity in the two methods which were used in our study. The results were statistically significant for Amikacin, Ceftriaxone, Cefixime, and Nitrofurantoin. The data was analyzed by Mc Memar test.Conclusion: According to our study the results of antibiotic susceptibility were more compatible with other non national Disk diffusion agar test and thus we recommend that our manufactures in Iran should increase the quality of their products.

  10. Genomic diversity and fitness of E. coli strains recovered from the intestinal and urinary tracts of women with recurrent urinary tract infection

    Science.gov (United States)

    Chen, Swaine L.; Wu, Meng; Henderson, Jeffrey P.; Hooton, Thomas M.; Hibbing, Michael E.; Hultgren, Scott J.; Gordon, Jeffrey I.

    2013-01-01

    Urinary tract infections (UTIs) are common in women and recurrence is a major clinical problem. Most UTIs are caused by uropathogenic Escherichia coli (UPEC). UPEC are generally thought to migrate from the gut to the bladder to cause UTI. UPEC strains form specialized intracellular bacterial communities (IBCs) in the bladder urothelium as part of a pathogenic mechanism to establish a foothold during acute stages of infection. Evolutionarily, such a specific adaptation to the bladder environment would be predicted to result in decreased fitness in other habitats, such as the gut. To examine this concept, we characterized 45 E. coli strains isolated from the feces and urine of four otherwise healthy women with recurrent UTIs. Multi-locus sequence typing revealed that two of the patients maintained a clonal population in both of these body habitats throughout their recurrent UTIs, whereas the other two manifested a wholesale shift in the dominant UPEC strain colonizing their urinary tract and gut between UTIs. These results were confirmed when we subjected 26 isolates from two patients, one representing the persistent clonal pattern and the other representing the dynamic population shift, to whole genome sequencing. In vivo competition studies conducted in mouse models of bladder and gut colonization, using isolates taken from one of the patients with a wholesale population shift, and a newly developed SNP-based method for quantifying strains, revealed that the strain that dominated in her last UTI episode had increased fitness in both body habitats relative to the one that dominated in the preceding episodes. Furthermore, increased fitness was correlated with differences in the strains’ gene repertoires and their in vitro carbohydrate and amino acid utilization profiles. Thus, UPEC appear capable of persisting in both the gut and urinary tract without a fitness tradeoff. Determination of all of the potential reservoirs for UPEC strains that cause recurrent UTI will

  11. The effect of essential oil of basil (Ocimum basilicum L.) on UV-induced mutagenesis in Escherichia coli and Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Stanojević, Jasna; Berić, Tanja; Opačić, Biljana; Vuković-Gačić, Branka; Simić, Draga; Knežević-Vukčević, Jelena [Institute of Botany, Faculty of Biology, University of Belgrade, 11000 Belgrade (Serbia)

    2008-07-01

    The antimutagenic potential of essential oil (EO) of basil (Ocimum basilicum L.) and its major constituent linalool were studied with the E. coli K12 and S. cerevisiae D7 assays. In the E. coli assay, EO and linalool inhibited UV-induced mutagenesis in a repair-proficient strain, but had no effect on spontaneous mutagenesis in repair-proficient, nucleotide excision repair-deficient, and mismatch-deficient strains. By testing participation of different mechanisms involved in antimutagenesis, it was concluded that the antimutagenic effect against UV-induced mutagenesis involved decrease of protein synthesis and cell proliferation which led to increased efficiency of nucleotide excision repair. An antimutagenic effect of basil derivatives in S. cerevisiae was not detected. (author)

  12. The effect of essential oil of basil (Ocimum basilicum L.) on UV-induced mutagenesis in Escherichia coli and Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Stanojević, Jasna; Berić, Tanja; Opačić, Biljana; Vuković-Gačić, Branka; Simić, Draga; Knežević-Vukčević, Jelena

    2008-01-01

    The antimutagenic potential of essential oil (EO) of basil (Ocimum basilicum L.) and its major constituent linalool were studied with the E. coli K12 and S. cerevisiae D7 assays. In the E. coli assay, EO and linalool inhibited UV-induced mutagenesis in a repair-proficient strain, but had no effect on spontaneous mutagenesis in repair-proficient, nucleotide excision repair-deficient, and mismatch-deficient strains. By testing participation of different mechanisms involved in antimutagenesis, it was concluded that the antimutagenic effect against UV-induced mutagenesis involved decrease of protein synthesis and cell proliferation which led to increased efficiency of nucleotide excision repair. An antimutagenic effect of basil derivatives in S. cerevisiae was not detected. (author)

  13. Methylglyoxal and other carbohydrate metabolites induce lanthanum-sensitive Ca2+ transients and inhibit growth in E. coli.

    Science.gov (United States)

    Campbell, Anthony K; Naseem, Riffat; Holland, I Barry; Matthews, Stephanie B; Wann, Kenneth T

    2007-12-01

    The results here are the first demonstration of a family of carbohydrate fermentation products opening Ca2+ channels in bacteria. Methylglyoxal, acetoin (acetyl methyl carbinol), diacetyl (2,3 butane dione), and butane 2,3 diol induced Ca2+ transients in Escherichia coli, monitored by aequorin, apparently by opening Ca2+ channels. Methylglyoxal was most potent (K(1/2) = 1 mM, 50 mM for butane 2,3 diol). Ca2+ transients depended on external Ca2+ (0.1-10 mM), and were blocked by La3+ (5 mM). The metabolites affected growth, methylglyoxal being most potent, blocking growth completely up to 5 h without killing the cells. But there was no affect on the number of viable cells after 24 h. These results were consistent with carbohydrate products activating a La3+-sensitive Ca2+ channel, rises in cytosolic Ca2+ possibly protecting against certain toxins. They have important implications in bacterial-host cell signalling, and where numbers of different bacteria compete for the same substrates, e.g., the gut in lactose and food intolerance.

  14. pH-induced conformational changes of AcrA, the membrane fusion protein of Escherichia coli multidrug efflux system.

    Science.gov (United States)

    Ip, Hermia; Stratton, Kelly; Zgurskaya, Helen; Liu, Jun

    2003-12-12

    The multidrug efflux system AcrA-AcrB-TolC of Escherichia coli expels a wide range of drugs directly into the external medium from the bacterial cell. The mechanism of the efflux process is not fully understood. Of an elongated shape, AcrA is thought to span the periplasmic space coordinating the concerted operation of the inner and outer membrane proteins AcrB and TolC. In this study, we used site-directed spin labeling (SDSL) EPR (electron paramagnetic resonance) spectroscopy to investigate the molecular conformations of AcrA in solution. Ten AcrA mutants, each with an alanine to cysteine substitution, were engineered, purified, and labeled with a nitroxide spin label. EPR analysis of spin-labeled AcrA variants indicates that the side chain mobilities are consistent with the predicted secondary structure of AcrA. We further demonstrated that acidic pH induces oligomerization and conformational change of AcrA, and that the structural changes are reversible. These results suggest that the mechanism of action of AcrA in drug efflux is similar to the viral membrane fusion proteins, and that AcrA actively mediates the efflux of substrates.

  15. Near-ultraviolet radiation-induced lipid peroxidation and membrane effects in Escherichia coli and human skin fibroblasts

    International Nuclear Information System (INIS)

    Chamberlain, J.

    1987-01-01

    The first part of this thesis examines the response of an unsaturated fatty acid auxotroph, Escherichia coli K1060 to broad-band near-UV radiation. Sensitivity, lipid peroxidation and leakage of rubidium from irradiated cells were found to increase with increasing unsaturation of membrane fatty acids. The involvement of singlet oxygen was implicated by an increase in sensitivity, lipid peroxidation and leakage of rubidium following irradiation in deuterium oxide. Some factors influencing survival following irradiation were investigated, where lower growth rates were shown to enhance survival. In the second part, the study was extended to human fibroblasts where a normal human skin fibroblast strain, GM730 and a strain derived from an actinic reticuloid patient, AR6LO, are compared. Lipid peroxidation was measured in both cell lines following broad-band near-UV irradiation. Membrane activity, as assessed by the pinocytic uptake of 14 C-sucrose and its subsequent release from the cell, was measured. Near-UV irradiation was found to increase such activity in both strains. Vitamin E and Trolox-C were found to decrease this response in AR6LO but not GM730 cells. The final part consists of preliminary investigations into the near-UV induced peroxidation of fatty acids and liposomes, and the subsequent increase in the level of hydroperoxides in the hours following irradiation. (author)

  16. Nosema ceranae induced mortality in honey bees (Apis mellifera) depends on infection methods.

    Science.gov (United States)

    Milbrath, Meghan O; Xie, Xianbing; Huang, Zachary Y

    2013-09-01

    Nosema ceranae infection can reduce survival of the Western honey bee, Apis mellifera, but experiments examining its virulence have highly variable results. This variation may arise from differences in experimental techniques. We examined survival effects of two techniques: Nosema infection at day 1 without anesthesia and infection at day 5 using CO2 anesthesia. All bees infected with the latter method had poorer survival. Interestingly, these bees also had significantly fewer spores than bees infected without anesthesia. These results indicate that differences in Nosema ceranae-induced mortality in honey bees may be partially due to differences in experimental techniques. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. UV-induced tandem double mutations in the trpA gene of E. coli

    International Nuclear Information System (INIS)

    Piechocki, R.; Langhammer, R.

    1980-01-01

    The ultraviolet light induction of tandem double mutations in a reverse mutation system was shown using trpA mutants which are characterized by the codon sequences GAA and AAG in codon position 211. Among 597 Trp + independent revertants of the trpA (AAG211) strain 3 full revertants were detected arising from UV-induced tandem double base exchanges. In the codon unit 211 full revertants due to single base exchanges are at least 20 times as frequent as full revertants due to tandem double base exchanges. (author)

  18. Prevalence of Escherichia coli O157:H7 Bacterial Infections Associated With the Use of Animal Wastes in Louisiana for the Period 1996-2004

    Directory of Open Access Journals (Sweden)

    Paul B. Tchounwou

    2006-03-01

    Full Text Available Animal waste from dairy and poultry operations is an economical and commonly used fertilizer in the state of Louisiana. The application of animal waste to pasture lands not only is a source of fertilizer, but also allows for a convenient method of waste disposal. The disposal of animal wastes on land is a potential non-point source of water degradation. Human health is a major concern when considering the disposal of large quantities of animal waste. Health concerns could exist from exposure to pathogens and excess nitrogen associated with this form of pollution. The objective of this study was to collect and analyze health data related to Escherichia coli O157:H7 bacterial infections associated with the use of animal waste in Louisiana for the years 1996-2004. An analysis of adverse health effects associated with the use of animal waste in Louisiana was conducted based on the incidence/prevalence rate for the studied years. The number of reported cases increased during the summer months. Analysis of health data of the studied years showed that the number of reported disease cases of E. coli O157:H7 were highest among Caucasian infants in the 0-4 year old age category and in Caucasian children in the 5-9 year old age category. Although the number of cases declined with age, a slight increase in rates was seen among the elderly population. While the rate of reported cases per 100,000 people remained the same for the years of 1999 and 2000, the rate decreased by 60% from the year 2000 to 2001. A slight decline of the number of cases that was also reported for the years 2002 and 2003. The high rate of identification in the younger population may result from the prompt seeking of medical care when symptoms become evident among infants and young children as well as the frequent ordering of stool examination when symptoms become evident in this population group. It was also noted that areas that had a higher number of reported cases also had a greater

  19. Metabolic and adaptive immune responses induced in mice infected ...

    African Journals Online (AJOL)

    This study investigated metabolic and immuno-inflammatory responses of mice infected with tissue-dwelling larvae of Trichinella zimbabwensis and explored the relationship between infection, metabolic parameters and Th1/Th17 immune responses. Sixty (60) female BALB/c mice aged between 6 to 8 weeks old were ...

  20. Urinary tract infection: recent insight into the evolutionary arms race between uropathogenic Escherichia coli and our immune system.

    Science.gov (United States)

    Schwab, Sebastian; Jobin, Katarzyna; Kurts, Christian

    2017-12-01

    Urinary tract infections (UTIs) are among the most common bacterial infections worldwide. Humans evolved various immune-dependent and independent defense mechanisms, while pathogens evolved multiple virulence factors to fight back. This article summarizes recent findings regarding the arms race between hosts and pathogens in UTIs. It was recently reported that macrophage subsets regulate neutrophil-mediated defense in primary UTIs but seem to subvert adaptive immunity upon re-infection. Moreover, some bacterial strains can survive inside macrophages, leading to recurrent infections. Inflammasome activation results in infected host cell death and pathogen release, facilitating the removal of intracellular bacteria. As a counteraction, some bacteria evolved mechanisms to disrupt inflammasome activation. Mucosal-associated invariant T cells are further effectors that can lyse infected epithelial cells and release intracellular bacteria. Once released, the bacteria are phagocytosed by neutrophils. However, some bacteria can inhibit neutrophil migration and deprive neutrophils of nutrients. Furthermore, the complement system, considered generally bactericidal, is exploited by the bacteria for cellular invasion. Another weapon against UTI is antimicrobial peptides, e.g. ribonuclease 7, but its production is inhibited by certain bacterial strains. Thus the arms race in UTI is ongoing, and knowing the enemy's methods can help in developing new drugs to win the race. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  1. Bactericidal peptidoglycan recognition protein induces oxidative stress in Escherichia coli through a block in respiratory chain and increase in central carbon catabolism.

    Science.gov (United States)

    Kashyap, Des R; Kuzma, Marcin; Kowalczyk, Dominik A; Gupta, Dipika; Dziarski, Roman

    2017-09-01

    Mammalian Peptidoglycan Recognition Proteins (PGRPs) kill both Gram-positive and Gram-negative bacteria through simultaneous induction of oxidative, thiol and metal stress responses in bacteria. However, metabolic pathways through which PGRPs induce these bactericidal stress responses are unknown. We screened Keio collection of Escherichia coli deletion mutants and revealed that deleting genes for respiratory chain flavoproteins or for tricarboxylic acid (TCA) cycle resulted in increased resistance of E. coli to PGRP killing. PGRP-induced killing depended on the production of hydrogen peroxide, which required increased supply of NADH for respiratory chain oxidoreductases from central carbon catabolism (glycolysis and TCA cycle), and was controlled by cAMP-Crp. Bactericidal PGRP induced a rapid decrease in respiration, which suggested that the main source of increased production of hydrogen peroxide was a block in respiratory chain and diversion of electrons from NADH oxidoreductases to oxygen. CpxRA two-component system was a negative regulator of PGRP-induced oxidative stress. By contrast, PGRP-induced thiol stress (depletion of thiols) and metal stress (increase in intracellular free Zn 2+ through influx of extracellular Zn 2+ ) were mostly independent of oxidative stress. Thus, manipulating pathways that induce oxidative, thiol and metal stress in bacteria could be a useful strategy to design new approaches to antibacterial therapy. © 2017 John Wiley & Sons Ltd.

  2. Randomized controlled trial of piperacillin-tazobactam, cefepime and ertapenem for the treatment of urinary tract infection caused by extended-spectrum beta-lactamase-producing Escherichia coli.

    Science.gov (United States)

    Seo, Yu Bin; Lee, Jacob; Kim, Young Keun; Lee, Seung Soon; Lee, Jeong-A; Kim, Hyo Youl; Uh, Young; Kim, Han-Sung; Song, Wonkeun

    2017-06-07

    Due to limited therapeutic options, the spread of extended-spectrum beta-lactamases (ESBLs) have become a major public health concern. We conducted a prospective, randomized, open-label comparison of the therapeutic efficacy of piperacillin-tazobactam (PTZ), cefepime, and ertapenem in febrile nosocomial urinary tract infection with ESBL-producing Escherichia coli (ESBL-EC). This study was conducted at three university hospitals between January 2013 and August 2015. Hospitalized adult patients presenting with fever were screened for healthcare-associated urinary tract infection (HA-UTI). When ESBL-EC was solely detected and susceptible to a randomized antibiotic in vitro, the case was included in the final analysis. Participants were treated for 10-14 days with PTZ, cefepime, or ertapenem. A total of 66 participants were evenly assigned to the PTZ and ertapenem treatment groups. After the recruitment of six participants, assignment to the cefepime treatment group was stopped because of an unexpectedly high treatment failure rate. The baseline characteristics of these participants did not differ from participants in other treatment groups. The clinical and microbiological response to PTZ treatment was estimated to be 94% and was similar to the response to ertapenem treatment. The efficacy of cefepime was 33.3%. In the cefepime group, age, Charlson comorbidity index, genotype, and minimal inhibitory concentration (MIC) did not significantly affect the success of treatment. Similarly, genotype seemed to be irrelevant with respect to clinical outcome in the PTZ group. Expired cases tended to involve septic shock with a high Charlson comorbidity index and high MIC. Results from this study suggest that PTZ is effective in the treatment of urinary tract infection caused by ESBL-EC when the in vitro test indicates susceptibility. In addition, cefepime should not be used as an alternative treatment for urinary tract infection caused by ESBL-EC. The trial was registered with

  3. Dissolution of infection-induced struvite bladder stones by using a noncalculolytic diet and antibiotic therapy

    Science.gov (United States)

    2004-01-01

    Abstract An 8-year-old, female spayed miniature schnauzer was presented for pollakiuria and gross hematuria. Infection-induced struvite urolithiasis with concurrent bacterial urinary tract infection was diagnosed. The treatment is described, followed by a brief discussion of struvite stones and their medical management. PMID:15532883

  4. Drug-induced hypersensitivity syndrome associated with Epstein-Barr virus infection.

    Science.gov (United States)

    Descamps, V; Mahe, E; Houhou, N; Abramowitz, L; Rozenberg, F; Ranger-Rogez, S; Crickx, B

    2003-05-01

    Association of drug-induced hypersensitivity syndrome with viral infection is debated. Human herpesvirus 6 (HHV-6) reactivation has been the most frequently reported infection associated with this syndrome. However, a case of cytomegalovirus (CMV) infection was recently described associated with anticonvulsant-induced hypersensitivity syndrome. We report a case of severe allopurinol-induced hypersensitivity syndrome with pancreatitis associated with Epstein-Barr virus (EBV) infection. Active EBV infection was demonstrated in two consecutive serum samples by the presence of anti-EBV early antigen (EA) IgM antibodies and an increase in anti-EBV EA IgG antibodies, whereas no anti-EBV nuclear antigen IgG antibodies were detected. EBV DNA was detected by polymerase chain reaction (PCR) in peripheral blood mononuclear cells. Reactivation of HHV-6 was suggested only by the presence of anti-HHV-6 IgM antibodies, but HHV-6 DNA was not detected by PCR in the serum. Other viral investigations showed previous infection (CMV, rubella, measles, parvovirus B19), immunization after vaccination (hepatitis B virus), or absence of previous infection (hepatitis C virus, human immunodeficiency virus). We suggest that EBV infection may participate in some cases, as do the other herpesviruses HHV-6 or CMV, in the development of drug-induced hypersensitivity syndrome.

  5. Malaria Parasite Infection and Chloroquine-Induced Pruritus: The ...

    African Journals Online (AJOL)

    induced body scratching, whereas, the histaminergic system was implicated in CQ-induced itching. Keywords: Rats, parasitaemia, chloroquine, opioids, antihistamine, naltrexone. West African Journal of Pharmacology and Drug Research Vol.

  6. N-Methyl-d-Aspartate (NMDA) Receptor Blockade Prevents Neuronal Death Induced by Zika Virus Infection.

    Science.gov (United States)

    Costa, Vivian V; Del Sarto, Juliana L; Rocha, Rebeca F; Silva, Flavia R; Doria, Juliana G; Olmo, Isabella G; Marques, Rafael E; Queiroz-Junior, Celso M; Foureaux, Giselle; Araújo, Julia Maria S; Cramer, Allysson; Real, Ana Luíza C V; Ribeiro, Lucas S; Sardi, Silvia I; Ferreira, Anderson J; Machado, Fabiana S; de Oliveira, Antônio C; Teixeira, Antônio L; Nakaya, Helder I; Souza, Danielle G; Ribeiro, Fabiola M; Teixeira, Mauro M

    2017-04-25

    Zika virus (ZIKV) infection is a global health emergency that causes significant neurodegeneration. Neurodegenerative processes may be exacerbated by N -methyl-d-aspartate receptor (NMDAR)-dependent neuronal excitoxicity. Here, we have exploited the hypothesis that ZIKV-induced neurodegeneration can be rescued by blocking NMDA overstimulation with memantine. Our results show that ZIKV actively replicates in primary neurons and that virus replication is directly associated with massive neuronal cell death. Interestingly, treatment with memantine or other NMDAR blockers, including dizocilpine (MK-801), agmatine sulfate, or ifenprodil, prevents neuronal death without interfering with the ability of ZIKV to replicate in these cells. Moreover, in vivo experiments demonstrate that therapeutic memantine treatment prevents the increase of intraocular pressure (IOP) induced by infection and massively reduces neurodegeneration and microgliosis in the brain of infected mice. Our results indicate that the blockade of NMDARs by memantine provides potent neuroprotective effects against ZIKV-induced neuronal damage, suggesting it could be a viable treatment for patients at risk for ZIKV infection-induced neurodegeneration. IMPORTANCE Zika virus (ZIKV) infection is a global health emergency associated with serious neurological complications, including microcephaly and Guillain-Barré syndrome. Infection of experimental animals with ZIKV causes significant neuronal damage and microgliosis. Treatment with drugs that block NMDARs prevented neuronal damage both in vitro and in vivo These results suggest that overactivation of NMDARs contributes significantly to the neuronal damage induced by ZIKV infection, and this is amenable to inhibition by drug treatment. Copyright © 2017 Costa et al.

  7. Myxoviruses do not induce non-specific alterations in membrane permeability early on in infection

    International Nuclear Information System (INIS)

    Foster, K.A.; Micklem, K.J.; Bogomolova, N.N.; Boriskin, Y.S.; Pasternak, C.A.

    1983-01-01

    The permeability characteristics of cells infected with myxoviruses have been studied by measuring the concentrative uptake of nutrients, the concentration of intracellular K + , and the maintenance of the Na + gradient across the plasma membrane. Cells either show no change at all (Sendai virus-infected BHK cells and measles virus-infected Vero cells) or they show a decreased ability to concentrate nutrients, while intracellular K + and the Na + gradient remain unchanged (Sendai and influenza virus-infected L-1210 cells, measles virus-infected lymphocytes and mumps virus-infected L-41 cells). In no case, therefore, was a change observed that resembles the non-specific increase in membrane permeability induced by haemolytic paramyxoviruses (35, 42) or the non-specific membrane leakiness postulated to take place in infected cells (8, 9). A preliminary account of some of these findings has been presented (39)

  8. An optimised method for the extraction of bacterial mRNA from plant roots infected with Escherichia coli O157:H7

    Directory of Open Access Journals (Sweden)

    Ashleigh eHolmes

    2014-06-01

    Full Text Available Analysis of microbial gene expression during host colonisation provides valuable information on the nature of interaction, beneficial or pathogenic, and the adaptive processes involved. Isolation of bacterial mRNA for in planta analysis can be challenging where host nucleic acid may dominate the preparation, or inhibitory compounds affect downstream analysis, e.g. qPCR, microarray or RNA-seq. The goal of this work was to optimise the isolation of bacterial mRNA of food-borne pathogens from living plants. Reported methods for recovery of phytopathogen-infected plant material, using hot phenol extraction and high concentration of bacterial inoculation or large amounts of infected tissues, were found to be inappropriate for plant roots inoculated with Escherichia coli O157:H7. The bacterial RNA yields were too low and increased plant material resulted in a dominance of plant RNA in the sample. To improve the yield of bacterial RNA and reduce the number of plants required, an optimised method was developed which combines bead beating with directed bacterial lysis using SDS and lysozyme. Inhibitory plant compounds, such as phenolics and polysaccharides, were counteracted with the addition of HMW-PEG and CTAB. The new method increased the total yield of bacterial mRNA substantially and allowed assessment of gene expression by qPCR. This method can be applied to other bacterial species associated with plant roots, and also in the wider context of food safety.

  9. Ebola virus infection induces irregular dendritic cell gene expression.

    Science.gov (United States)

    Melanson, Vanessa R; Kalina, Warren V; Williams, Priscilla

    2015-02-01

    Filoviruses subvert the human immune system in part by infecting and replicating in dendritic cells (DCs). Using gene arrays, a phenotypic profile of filovirus infection in human monocyte-derived DCs was assessed. Monocytes from human donors were cultured in GM-CSF and IL-4 and were infected with Ebola virus Kikwit variant for up to 48 h. Extracted DC RNA was analyzed on SuperArray's Dendritic and Antigen Presenting Cell Oligo GEArray and compared to uninfected controls. Infected DCs exhibited increased expression of cytokine, chemokine, antiviral, and anti-apoptotic genes not seen in uninfected controls. Significant increases of intracellular antiviral and MHC I and II genes were also noted in EBOV-infected DCs. However, infected DCs failed to show any significant difference in co-stimulatory T-cell gene expression from uninfected DCs. Moreover, several chemokine genes were activated, but there was sparse expression of chemokine receptors that enabled activated DCs to home to lymph nodes. Overall, statistically significant expression of several intracellular antiviral genes was noted, which may limit viral load but fails to stop replication. EBOV gene expression profiling is of vital importance in understanding pathogenesis and devising novel therapeutic treatments such as small-molecule inhibitors.

  10. Indigenous lactobacilli strains of food and human sources reverse enteropathogenic E. coli O26:H11-induced damage in intestinal epithelial cell lines: effect on redistribution of tight junction proteins.

    Science.gov (United States)

    Jariwala, Ruchi; Mandal, Hemanti; Bagchi, Tamishraha

    2017-09-01

    The aim of the study was to investigate the neutralizing effect of lactobacilli isolated from indigenous food and human sources on enteropathogenic Escherichia coli (EPEC) O26 : H11-induced epithelial barrier dysfunction in vitro. This was assessed by transepithelial electrical resistance (TEER) and permeability assays using intestinal cell lines, HT-29 and Caco-2. Furthermore, the expression and distribution of tight junction (TJ) proteins were analysed by qRT-PCR and immunofluorescence assay, respectively. The nine strains used in the study were from different species viz. Lactobacillus fermentum, Lactobacillushelveticus, Lactobacillus salivarius and Lactobacillus plantarum. All strains were able to reverse the decrease in TEER and corresponding increase in permeability across E. coli-infected monolayers. Maximum reversal was observed after 18 h [up to 93.8±2.0 % by L. rhamnosus GG followed by L. fermentum IIs11.2 (92.6±2.2 %) and L. plantarum GRI-2 (91.9±0.9 %)] of lactobacilli exposure following EPEC O26 : H11 infection. All strains were able to redistribute the TJ proteins to the cell periphery either partially or completely. Moreover, L. helveticus FA-7 was also able to significantly increase the mRNA expression of ZO-1 and claudin-1 (2.5-fold and 3.0-fold, respectively; PGRI-2 were good in all the aspects studied, and the other strains were good in some aspects. L. helveticus FA-7, L. fermentum FA-1 and L. plantarum GRI-2 can therefore be used for potential therapeutic purpose against intestinal epithelial dysfunction.

  11. Porphyromonas gingivalis infection induced reproductive abnormalities in mice

    Directory of Open Access Journals (Sweden)

    Ke-min WEI

    2016-09-01

    Full Text Available Objective  To establish a pregnant mouse model infected with Porphyromonas gingivalis (P.g, and investigate the relationship of P.g infection to prematurity and associated birth abnormalities. Methods  Fifty two female mice were randomly divided into P.g infection group (n=26 and control group (n=26. Mice in P.g infection group were anesthetized, the pulp cavity of the first molar was opened and directly injected with W83 strain P.g, and the tooth was then filled. Six weeks after infection, the mice were mated with males and the formation of vagina plug was recorded as 0d. The P.g extracted from the granulation tissue in tooth root was cultivated. The pregnant days and the connatal body weight of infant mouse were recorded, the serum and placental tissue were collected to assess the systemic and local conditions during pregnancy. Results  After periodontal P.g infection, the TNF-α, IL-17, IL -6 and IL -1βlevels in peripheral blood sera increased significantly. The average gestation was shorter in P.g infection group (18.25d than in control group (20.45d, P<0.01, and the connatal body weight of infant mouse was also less in the former than in the latter (P<0.01. Immunohistochemistry and PCR revealed the existence of P.g in placenta tissue. P.g infection caused premature rupture of membranes, placental abruption, degeneration and necrosis of trophoblastic and endothelial cells; significantly increased the number of neutrophils and macrophages in placenta tissues, and increased the expression of local TNF-αand COX-2 inflammatory factors at the same time. In P.g infection group, the expressions of CD-31 in endothelial cells of placenta tissues and the apoptotic factor caspase-3 decreased, and the DNA oxidative damage index 8-OHdG increased. Conclusions  P.g infection in female mice may cause premature birth and lower connatal body weight of infant mouse, and increase the expression of serous and local inflammatory factors in the placenta

  12. In-vitro Antibiotic Resistance Profile of E. coli Strains Isolated from Community-acquired Paediatric Urinary Tract Infections in Karabuk Province

    Directory of Open Access Journals (Sweden)

    Nergis Asgin

    2017-09-01

    Results: A total of 410 uropathogenic E.coli strains were isolated from 328 (80% female and 82 (20% male patients. In all age groups, E.coli was more frequently isolated from girls. There was a statistically significant difference between female gender and E. coli isolation rates in all age groups (p [J Contemp Med 2017; 7(3.000: 241-245

  13. Leishmania donovani infection induces anemia in hamsters by differentially altering erythropoiesis in bone marrow and spleen.

    Directory of Open Access Journals (Sweden)

    William P Lafuse

    Full Text Available Leishmania donovani is a parasite that causes visceral leishmaniasis by infecting and replicating in macrophages of the bone marrow, spleen, and liver. Severe anemia and leucopenia is associated with the disease. Although immune defense mechanisms against the parasite have been studied, we have a limited understanding of how L. donovani alters hematopoiesis. In this study, we used Syrian golden hamsters to investigate effects of L. donovani infection on erythropoiesis. Infection resulted in severe anemia and leucopenia by 8 weeks post-infection. Anemia was associated with increased levels of serum erythropoietin, which indicates the hamsters respond to the anemia by producing erythropoietin. We found that infection also increased numbers of BFU-E and CFU-E progenitor populations in the spleen and bone marrow and differentially altered erythroid gene expression in these organs. In the bone marrow, the mRNA expression of erythroid differentiation genes (α-globin, β-globin, ALAS2 were inhibited by 50%, but mRNA levels of erythroid receptor (c-kit, EpoR and transcription factors (GATA1, GATA2, FOG1 were not affected by the infection. This suggests that infection has a negative effect on differentiation of erythroblasts. In the spleen, erythroid gene expression was enhanced by infection, indicating that the anemia activates a stress erythropoiesis response in the spleen. Analysis of cytokine mRNA levels in spleen and bone marrow found that IFN-γ mRNA is highly increased by L. donovani infection. Expression of the IFN-γ inducible cytokine, TNF-related apoptosis-inducing ligand (TRAIL, was also up-regulated. Since TRAIL induces erythroblasts apoptosis, apoptosis of bone marrow erythroblasts from infected hamsters was examined by flow cytometry. Percentage of erythroblasts that were apoptotic was significantly increased by L. donovani infection. Together, our results suggest that L. donovani infection inhibits erythropoiesis in the bone marrow by

  14. GroEL and dnaK genes of Escherichia coli are induced by UV irradiation and nalidixic acid in an htpR+-dependent fashion

    International Nuclear Information System (INIS)

    Krueger, J.H.; Walker, G.C.

    1984-01-01

    Two proteins with molecular weights of 61,000 and 73,000 were found to be induced by UV light in Escherichia coli mutants in which the SOS responses are constitutively expressed. The induction of these proteins by UV light and nalidixic acid was shown to be independent of the recA + lexA + regulatory system. Analysis of these proteins by two-dimensional gel electrophoresis and comparison with the heat-shock proteins of E. coli revealed that the M/sub r/ 61,000 protein comigrated with the groEL gene product, that the M/sub r/ 73,000 protein comigrated with the dnaK gene product, and that other heat-shock proteins were also induced. The induction of groEL and dnaK by UV light and nalidixic acid is controlled by the htpR locus. The results suggest that the regulatory response of E. coli to agents such as UV light and nalidixic acid is more complex than previously thought. 35 references, 6 figures, 1 table

  15. Effects of alterations of the E. coli lipopolysaccharide layer on membrane permeabilization events induced by Cecropin A.

    Science.gov (United States)

    Agrawal, Anurag; Weisshaar, James C

    2018-04-22

    The outermost layer of Gram negative bacteria is composed of a lipopolysaccharide (LPS) network that forms a dense protective hydrophilic barrier against entry of hydrophobic drugs. At low μM concentrations, a large family of cationic polypeptides known as antimicrobial peptides (AMPs) are able to penetrate the LPS layer and permeabilize the outer membrane (OM) and the cytoplasmic membrane (CM), causing cell death. Cecropin A is a well-studied cationic AMP from moth. Here a battery of time-resolved, single-cell microscopy experiments explores how deletion of sugar layers and/or phosphoryl negative charges from the core oligosaccharide layer (core OS) of K12 E. coli alters the timing of OM and CM permeabilization induced by Cecropin A. Deletion of sugar layers, or phosphoryl charges, or both from the core OS shortens the time to the onset of OM permeabilization to periplasmic GFP and also the lag time between OM permeabilization and CM permeabilization. Meanwhile, the 12-h minimum inhibitory concentration (MIC) changes only twofold with core OS alterations. The results suggest a two-step model in which the core oligosaccharide layers act as a kinetic barrier to penetration of Cecropin A to the lipid A outer leaflet of the OM. Once a threshold concentration has built up at the lipid A leaflet, nucleation occurs and the OM is locally permeabilized to GFP and, by inference, to Cecropin A. Whenever Cecropin A permeabilizes the OM, CM permeabilization always follows, and cell growth subsequently halts and never recovers on the 45 min observation timescale. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Light induced expression of β-glucosidase in Escherichia coli with autolysis of cell.

    Science.gov (United States)

    Chang, Fei; Zhang, Xianbing; Pan, Yu; Lu, Youxue; Fang, Wei; Fang, Zemin; Xiao, Yazhong

    2017-11-07

    β-Glucosidase has attracted substantial attention in the scientific community because of its pivotal role in cellulose degradation, glycoside transformation and many other industrial processes. However, the tedious and costly expression and purification procedures have severely thwarted the industrial applications of β-glucosidase. Thus development of new strategies to express β-glucosidases with cost-effective and simple procedure to meet the increasing demands on enzymes for biocatalysis is of paramount importance. Light activated cassette YF1/FixJ and the SRRz lysis system were successfully constructed to produce Bgl1A(A24S/F297Y), a mutant β-glucosidase tolerant to both glucose and ethanol. By optimizing the parameters for light induction, Bgl1A(A24S/F297Y) activity reached 33.22 ± 2.0 U/mL and 249.92 ± 12.25 U/mL in 250-mL flask and 3-L fermentation tank, respectively, comparable to the controls of 34.02 ± 1.96 U/mL and 322.21 ± 10.16 U/mL under similar culture conditions with IPTG induction. To further simplify the production of our target protein, the SRRz lysis gene cassette from bacteriophage Lambda was introduced to trigger cell autolysis. As high as 84.53 ± 6.79% and 77.21 ± 4.79% of the total β-glucosidase were released into the lysate after cell autolysis in 250 mL flasks and 3-L scale fermentation with lactose as inducer of SRRz. In order to reduce the cost of protein purification, a cellulose-binding module (CBM) from Clostridium thermocellum was fused into the C-terminal of Bgl1A(A24S/F297Y) and cellulose was used as an economic material to adsorb the fusion enzyme from the lysate. The yield of the fusion protein could reach 92.20 ± 2.27% after one-hour adsorption at 25 °C. We have developed an efficient and inexpensive way to produce β-glucosidase for potential industrial applications by using the combination of light induction, cell autolysis, and CBM purification strategy.

  17. Bovine natural killer cells are present in Escherichia coli infected mammary gland tissue and show antimicrobial activity in vitro

    NARCIS (Netherlands)

    Sipka, Anja; Pomeroy, Brianna; Klaessig, Suzanne; Schukken, Ynte

    2016-01-01

    Natural killer (NK) cells are early responders in bacterial infections but their role in bovine mastitis has not been characterized. For the first time, we show the presence of NK cells (NKp46+/CD3) in bovine mammary gland tissue after an intramammary challenge with

  18. Clinical and bacteriological effects of pivmecillinam for ESBL-producing Escherichia coli or Klebsiella pneumoniae in urinary tract infections

    DEFF Research Database (Denmark)

    Jansåker, Filip; Frimodt-Møller, Niels; Sjögren, Ingegerd

    2014-01-01

    The prevalence of urinary tract infections (UTIs) caused by extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is increasing and the therapeutic options are limited, especially in primary care. Recent indications have suggested pivmecillinam to be a suitable option. Here, we...... evaluated the clinical and bacteriological effects of pivmecillinam in UTIs caused by ESBL-producing Enterobacteriaceae....

  19. Effects of Auger cascades of bromine induced by K-shell photoionization on plasmid DNA, bacteriophages, E.coli and yeast cells

    International Nuclear Information System (INIS)

    Maezawa, Hiroshi; Ito, Takashi

    1988-01-01

    When bromouracil-labelled E.coli cells were irradiated with X-rays cells killing was enhanced above the absorption edge, 13.49 keV, by 8% as compared with 12.40 keV (below the edge) only in the presence of 7.8% DMSO. In the case of dried BrdU-labelled T1 phage, a larger (about 26%) enhancing effect was observed. This would partly be due to the incomplete suppression of radical mediated process in E.coli cells. Various degrees of energy-dependent enhancement observed in the different biological systems are discussed both from the induced number of Auger events and from the increased energy absorption due to the presence of Br atoms in the system. (author)

  20. (ESBL) producing Escherichia coli and Klebsiella pneumoniae

    African Journals Online (AJOL)

    use

    2011-11-21

    Nov 21, 2011 ... the most common serious bacterial infections in infants ... UTI is a common cause of morbidity .... of ESBL and non-ESBL producing Escherichia coli and Klebsiella pneumonia. ... in hospital and community acquired infections.

  1. Global genome response of Escherichia coli O157∶H7 Sakai during dynamic changes in growth kinetics induced by an abrupt downshift in water activity.

    Directory of Open Access Journals (Sweden)

    Chawalit Kocharunchitt

    Full Text Available The present study was undertaken to investigate growth kinetics and time-dependent change in global expression of Escherichia coli O157∶H7 Sakai upon an abrupt downshift in water activity (aw. Based on viable count data, shifting E. coli from aw 0.993 to aw 0.985 or less caused an apparent loss, then recovery, of culturability. Exponential growth then resumed at a rate characteristic for the aw imposed. To understand the responses of this pathogen to abrupt osmotic stress, we employed an integrated genomic and proteomic approach to characterize its cellular response during exposure to a rapid downshift but still within the growth range from aw 0.993 to aw 0.967. Of particular interest, genes and proteins with cell envelope-related functions were induced during the initial loss and subsequent recovery of culturability. This implies that cells undergo remodeling of their envelope composition, enabling them to adapt to osmotic stress. Growth at low aw, however, involved up-regulating additional genes and proteins, which are involved in the biosynthesis of specific amino acids, and carbohydrate catabolism and energy generation. This suggests their important role in facilitating growth under such stress. Finally, we highlighted the ability of E. coli to activate multiple stress responses by transiently inducing the RpoE and RpoH regulons to control protein misfolding, while simultaneously activating the master stress regulator RpoS to mediate long-term adaptation to hyperosmolality. This investigation extends our understanding of the potential mechanisms used by pathogenic E. coli to adapt, survive and grow under osmotic stress, which could potentially be exploited to aid the selection and/or development of novel strategies to inactivate this pathogen.

  2. Effect of mild heat stress and mild infection pressure on immune responses to an E. coli infection in chickens

    DEFF Research Database (Denmark)

    Norup, L R; Jensen, K H; Jørgensen, E

    2008-01-01

    Outdoor or organic farming demands robust chickens that are able to combat common infections before they spread to the flock. Priming the immune system of the chickens early in life with micro-organisms that they will encounter later in life prepares chickens to a life in environments where they ...

  3. Children with moderate-high infection with Entamoeba coli have higher percentage of body and abdominal fat than non-infected children

    NARCIS (Netherlands)

    Zavala, G A; García, O P; Campos-Ponce, M; Ronquillo, D.; Caamaño, M C; Doak, C M; Rosado, J.L.

    2016-01-01

    BACKGROUND: Intestinal parasites, virus and bacterial infections are positively associated with obesity and adiposity in vitro and in animal models, but conclusive evidence of this relationship in humans is lacking. The aim of this cross-sectional study was to determine differences in adiposity

  4. Associations Between Hydration Status, Intravenous Fluid Administration, and Outcomes of Patients Infected With Shiga Toxin-Producing Escherichia coli: A Systematic Review and Meta-analysis.

    Science.gov (United States)

    Grisaru, Silviu; Xie, Jianling; Samuel, Susan; Hartling, Lisa; Tarr, Phillip I; Schnadower, David; Freedman, Stephen B

    2017-01-01

    The associations between hydration status, intravenous fluid administration, and outcomes of patients infected with Shiga toxin-producing Escherichia coli (STEC) remain unclear. To determine the relationship between hydration status, the development and severity of hemolytic uremic syndrome (HUS), and adverse outcomes in STEC-infected individuals. MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials via the OvidSP platform, PubMed via the National Library of Medicine, CINAHL Plus with full text, Scopus, Web of Science, ClinicalTrials.gov, reference lists, and gray literature were systematically searched. Two reviewers independently identified studies that included patients with hydration status documentation, proven or presumed STEC infection, and some form of HUS that developed. No language restrictions were applied. Two reviewers independently extracted individual study data, including study characteristics, population, and outcomes. Risk of bias was assessed using the Newcastle-Ottawa Scale; strength of evidence was adjudicated using the Grading of Recommendations Assessment, Development, and Evaluation method. Meta-analyses were conducted using random-effects models. Development of HUS, complications (ie, oligoanuric renal failure, involvement of the central nervous system, or death), and interventions (ie, renal replacement therapy). Eight studies comprising 1511 patients (all children) met eligibility criteria. Unpublished data were provided by the authors of 7 published reports. The median risk-of-bias score was 7.5 (range, 6-9). No studies evaluated the effect of hydration during STEC infections on the risk for HUS. A hematocrit value greater than 23% as a measure of hydration status at presentation with HUS was associated with the development of oligoanuric HUS (OR, 2.38 [95% CI, 1.30-4.35]; I2 = 2%), renal replacement therapy (OR, 1.90 [95% CI, 1.25-2.90]; I2 = 17%), and death (OR, 5.13 [95% CI, 1.50-17.57]; I2 = 55%). Compared with

  5. Prevention of enterotoxigenic Escherichia coli infections in pigs by dairy-based nutrition

    DEFF Research Database (Denmark)

    Sugiharto, Sugiharto; Jensen, Bent Borg; Jensen, Karin Hjelholt

    2015-01-01

    bacterial disease outbreaks in piglets, the use of antibiotics at subtherapeutic concentrations has been banned in the European Union because of the increasing prevalence of resistance to antibiotics in pigs. The removal of in-feed antibiotics from piglet diets has negative economic consequences...... as it dramatically increases the rate of morbidity and mortality due to ETEC as well as the use of antibiotics for therapeutic purposes. Other than subtherapeutic antibiotics, zinc oxide (ZnO) has been reported to ameliorate and/or prevent the development of PWD in piglets, but its excretion may have negative...... impacts on the environment. Thus, other alternatives that can control ETEC infections in piglets postweaning will be of great advantage. A number of nutritional strategies have been proposed as alternative means of preventing ETEC infections, of which feeding dairy-based products to piglets could be one...

  6. Theileria parva infection induces autocrine growth of bovine lymphocytes.

    Science.gov (United States)

    Dobbelaere, D A; Coquerelle, T M; Roditi, I J; Eichhorn, M; Williams, R O

    1988-01-01

    Bovine lymphocytes infected with the parasite Theileria parva continuously secrete a growth factor that is essential for their proliferation in vitro and also constitutively express interleukin 2 receptors on their surface. Dilution of the secreted growth factor, caused by culturing cells at low density, results in retardation of culture growth. Human recombinant interleukin 2, however, effectively substitutes for the diluted growth factor by restoring normal growth rates and also allows Theileria-infected cells to be grown at low density without the use of feeder layers. Secretion of the growth factor and expression of the interleukin 2 receptor depend on the presence of the parasite in the cytoplasm of the host cell. Elimination of the parasite from the cell cytoplasm by the specific antitheilerial drug BW 720c results in the arrest of growth factor secretion and the disappearance of interleukin 2 receptors from the cell surface. This is accompanied by growth arrest and reversion of the infected cells to the morphology of resting lymphocytes. We propose that the continuous proliferation of infected cells in vitro is mediated by autocrine receptor activation. Images PMID:3133661

  7. Lentinan treatment of Plasmodium yoelii-infected mice induces ...

    African Journals Online (AJOL)

    Yomi

    2012-01-31

    Jan 31, 2012 ... infected mice results in down-regulation of the Th1-type immune response, leading to death (Wu et al., 2007;. Amante et al., 2007). Thus, these cells help to promote the pathogenesis of malaria. Several treatments are commonly used to combat malaria; most often is quinine administration (Sahu et al.,.

  8. Evaluation of a Novel Tc-99m Labelled Vitamin B12 Derivative for Targeting Escherichia coli and Staphylococcus aureus In Vitro and in an Experimental Foreign-Body Infection Model.

    Science.gov (United States)

    Baldoni, Daniela; Waibel, Robert; Bläuenstein, Peter; Galli, Filippo; Iodice, Violetta; Signore, Alberto; Schibli, Roger; Trampuz, Andrej

    2015-12-01

    Vitamin B12 (cyanocobalamin, Cbl) is accumulated by rapidly replicating prokaryotic and eukaryotic cells. We investigated the potential of a Tc-99m labelled Cbl derivative ([(99m)Tc]PAMA(4)-Cbl) for targeting infections caused by Escherichia coli and Staphylococcus aureus. In vitro binding assays were followed by biodistribution studies in a mouse model of foreign body infection. E. coli (ATCC 25922) and S. aureus (ATCC 43335) were used as test strains. [(57)Co]Cbl, [(67)Ga]citrate and [(99m)Tc]DTPA served as reference compounds. The in vitro competitive binding of [(57)Co]Cbl or [(99m)Tc]PAMA(4)-Cbl, and unlabeled Cbl, to viable or killed bacteria, was evaluated at 37 and 4 °C. A cage mouse model of infection was used for biodistribution of intravenous [(57)Co]Cbl and [(99m)Tc]PAMA(4)-Cbl in cage and dissected tissues of infected and non-infected mice. Maximum binding (mean ± SD) of [(57)Co]Cbl to viable E. coli was 81.7 ± 2.6 % and to S. aureus 34.0 ± 6.7 %, at 37 °C; no binding occurred to heat-killed bacteria. Binding to both test strains was displaced by 100- to 1000-fold excess of unlabeled Cbl. The in vitro binding of [(99m)Tc]PAMA(4)-Cbl was 100-fold and 3-fold lower than the one of [(57)Co]Cbl for E. coli and S. aureus, respectively. In vivo, [(99m)Tc]PAMA(4)-Cbl showed peak percentage of injected dose (% ID) values between 1.33 and 2.3, at 30 min post-injection (p.i.). Significantly higher retention occurred in cage fluids infected with S. aureus at 4 h and with E. coli at 8 h p.i. than in non-infected animals. Accumulation into infected cages was also higher than the one of [(99m)Tc]DTPA, which showed similar biodistribution in infected and sterile mice. [(57)Co]Cbl gradually accumulated in cages with peaks % ID between 3.58 and 4.83 % achieved from 24 to 48 h. Discrimination for infection occurred only in E. coli-infected mice, at 72 h p.i. [(67)Ga]citrate, which showed a gradual accumulation into cage fluids during 12 h, was

  9. Acute Viral Respiratory Infection Rapidly Induces a CD8+ T Cell Exhaustion-like Phenotype.

    Science.gov (United States)

    Erickson, John J; Lu, Pengcheng; Wen, Sherry; Hastings, Andrew K; Gilchuk, Pavlo; Joyce, Sebastian; Shyr, Yu; Williams, John V

    2015-11-01

    Acute viral infections typically generate functional effector CD8(+) T cells (TCD8) that aid in pathogen clearance. However, during acute viral lower respiratory infection, lung TCD8 are functionally impaired and do not optimally control viral replication. T cells also become unresponsive to Ag during chronic infections and cancer via signaling by inhibitory receptors such as programmed cell death-1 (PD-1). PD-1 also contributes to TCD8 impairment during viral lower respiratory infection, but how it regulates TCD8 impairment and the connection between this state and T cell exhaustion during chronic infections are unknown. In this study, we show that PD-1 operates in a cell-intrinsic manner to impair lung TCD8. In light of this, we compared global gene expression profiles of impaired epitope-specific lung TCD8 to functional spleen TCD8 in the same human metapneumovirus-infected mice. These two populations differentially regulate hundreds of genes, including the upregulation of numerous inhibitory receptors by lung TCD8. We then compared the gene expression of TCD8 during human metapneumovirus infection to those in acute or chronic lymphocytic choriomeningitis virus infection. We find that the immunophenotype of lung TCD8 more closely resembles T cell exhaustion late into chronic infection than do functional effector T cells arising early in acute infection. Finally, we demonstrate that trafficking to the infected lung alone is insufficient for TCD8 impairment or inhibitory receptor upregulation, but that viral Ag-induced TCR signaling is also required. Our results indicate that viral Ag in infected lungs rapidly induces an exhaustion-like state in lung TCD8 characterized by progressive functional impairment and upregulation of numerous inhibitory receptors. Copyright © 2015 by The American Association of Immunologists, Inc.

  10. Mycoplasma agalactiae Induces Cytopathic Effects in Infected Cells Cultured In Vitro.

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    Shrilakshmi Hegde

    Full Text Available Mycoplasma agalactiae is the etiological agent of the contagious agalactia syndrome in sheep and goats and causes significant economic losses worldwide. Yet the mechanism of pathogenesis is largely unknown. Even whole-genome sequence analysis of its pathogenic type strain did not lead to any conclusions regarding its virulence or pathogenicity factors. Although inflammation and tissue destruction at the local site of M. agalactiae infection are largely considered as effects of the host immune response, the direct effect of the agent on host cells is not completely understood. The aim of this study was to investigate the effect of M. agalactiae infection on the quality and viability of host cells in vitro. Changes in cell morphology including cell elongation, cytoplasm shrinkage and membrane blebbing were observed in infected HeLa cells. Chromatin condensation and increased caspase-3 cleavage in infected HeLa cells 48 h after infection suggests an apoptosis-like phenomenon in M. agalactiae-infected cells. In compliance with these results, decreased viability and cell lysis of M. agalactiae-infected HeLa cells was also observed. Measurement of the amount of LDH released after M. agalactiae infection revealed a time- and dose-dependent increase in HeLa cell lysis. A significant decrease in LDH released after gentamicin treatment of infected cells confirmed the major role of cytadherent M. agalactiae in inducing host cell lysis. This is the first study illustrating M. agalactiae's induction of cytopathic effects in infected HeLa cells. Further detailed investigation of infected host tissue for apoptotic markers might demonstrate the association between M. agalactiae-induced host cell lysis and the tissue destruction observed during M. agalactiae natural infection.

  11. Differential protection by cell wall components of Lactobacillus amylovorus DSM 16698Tagainst alterations of membrane barrier and NF-kB activation induced by enterotoxigenic F4+ Escherichia coli on intestinal cells.

    Science.gov (United States)

    Roselli, Marianna; Finamore, Alberto; Hynönen, Ulla; Palva, Airi; Mengheri, Elena

    2016-09-29

    The role of Lactobacillus cell wall components in the protection against pathogen infection in the gut is still largely unexplored. We have previously shown that L. amylovorus DSM 16698 T is able to reduce the enterotoxigenic F4 + Escherichia coli (ETEC) adhesion and prevent the pathogen-induced membrane barrier disruption through the regulation of IL-10 and IL-8 expression in intestinal cells. We have also demonstrated that L. amylovorus DSM 16698 T protects host cells through the inhibition of NF-kB signaling. In the present study, we investigated the role of L. amylovorus DSM 16698 T cell wall components in the protection against F4 + ETEC infection using the intestinal Caco-2 cell line. Purified cell wall fragments (CWF) from L. amylovorus DSM 16698 T were used either as such (uncoated, U-CWF) or coated with S-layer proteins (S-CWF). Differentiated Caco-2/TC7 cells on Transwell filters were infected with F4 + ETEC, treated with S-CWF or U-CWF, co-treated with S-CWF or U-CWF and F4 + ETEC for 2.5 h, or pre-treated with S-CWF or U-CWF for 1 h before F4 + ETEC addition. Tight junction (TJ) and adherens junction (AJ) proteins were analyzed by immunofluorescence and Western blot. Membrane permeability was determined by phenol red passage. Phosphorylated p65-NF-kB was measured by Western blot. We showed that both the pre-treatment with S-CWF and the co- treatment of S-CWF with the pathogen protected the cells from F4 + ETEC induced TJ and AJ injury, increased membrane permeability and activation of NF-kB expression. Moreover, the U-CWF pre-treatment, but not the co-treatment with F4 + ETEC, inhibited membrane damage and prevented NF-kB activation. The results indicate that the various components of L. amylovorus DSM 16698 T cell wall may counteract the damage caused by F4 + ETEC through different mechanisms. S-layer proteins are essential for maintaining membrane barrier function and for mounting an anti-inflammatory response against F4 + ETEC infection. U-CWF are

  12. The gut at war: the consequences of enteropathogenic Escherichia coli infection as a factor of diarrhea and malnutrition

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    Ulysses Fagundes-Neto

    2000-01-01

    Full Text Available Diarrheal disease is still the most prevalent and important public health problem in developing countries, despite advances in knowledge, understanding, and management that have occurred over recent years. Diarrhea is the leading cause of death in children under 5 years of age. The impact of diarrheal diseases is more severe in the earliest periods of life, when taking into account both the numbers of episodes per year and hospital admission rates. This narrative review focuses on one of the major driving forces that attack the host, namely the enteropathogenic Escherichia coli (EPEC and the consequences that generate malnutrition in an early phase of life. EPEC serotypes form dense microcolonies on the surface of tissue-culture cells in a pattern known as localized adherence (LA. When EPEC strains adhere to epithelial cells in vitro or in vivo they cause characteristic changes known as Attaching and Effacement (A/E lesions. Surface abnormalities of the small intestinal mucosa shown by scanning electron microscopy in infants with persistent diarrhea, although non-specific, are intense enough to justify the severity of the clinical aspects displayed in a very young phase in life. Decrease in number and height of microvilli, blunting of borders of enterocytes, loss of the glycocalyx, shortening of villi and presence of a mucus pseudomembrane coating the mucosal surface were the abnormalities observed in the majority of patients. These ultrastructural derangements may be due to an association of the enteric enteropathogenic agent that triggers the diarrheic process and the onset of food intolerance responsible for perpetuation of diarrhea. An aggressive therapeutic approach based on appropriate nutritional support, especially the utilization of human milk and/or lactose-free protein hydrolyzate-based formulas and the adequate correction of the fecal losses, is required to allow complete recovery from the damage caused by this devastating

  13. Quantitative Real-time Polymerase Chain Reaction for Enteropathogenic Escherichia coli: A Tool for Investigation of Asymptomatic Versus Symptomatic Infections

    Science.gov (United States)

    Barletta, Francesca; Mercado, Erik; Ruiz, Joaquim; Ecker, Lucie; Lopez, Giovanni; Mispireta, Monica; Gil, Ana I.; Lanata, Claudio F.; Cleary, Thomas G.

    2011-01-01

    Background. Enteropathogenic Escherichia coli (EPEC) strains are pediatric pathogens commonly isolated from both healthy and sick children with diarrhea in areas of endemicity. The aim of this study was to compare the bacterial load of EPEC isolated from stool samples from children with and without diarrhea to determine whether bacterial load might be a useful tool for further study of this phenomenon. Methods. EPEC was detected by polymerase chain reaction (PCR) of colonies isolated on MacConkey plates from 53 diarrheal and 90 healthy children aged <2 years. DNA was isolated from stool samples by cetyltrimethylammonium bromide extraction. To standardize quantification by quantitative real-time PCR (qRT-PCR), the correlation between fluorescence threshold cycle and copy number of the intimin gene of EPEC E2348/69 was determined. Results. The detection limit of qRT-PCR was 5 bacteria/mg stool. The geometric mean load in diarrhea was 299 bacteria/mg (95% confidence interval [CI], 77–1164 bacteria/mg), compared with 29 bacteria/mg (95% CI, 10–87 bacteria/mg) in control subjects (P = .016). Bacterial load was significantly higher in children with diarrhea than in control subjects among children <12 months of age (178 vs 5 bacteria/mg; P = .006) and among children with EPEC as the sole pathogen (463 vs 24 bacteria/mg; P = .006). Conclusions. EPEC load measured by qRT-PCR is higher in diarrheal than in healthy children. qRT-PCR may be useful to study the relationship between disease and colonization in settings of endemicity. PMID:22028433

  14. Mycobacterium tuberculosis infection induces non-apoptotic cell death of human dendritic cells

    LENUS (Irish Health Repository)

    Ryan, Ruth CM

    2011-10-24

    Abstract Background Dendritic cells (DCs) connect innate and adaptive immunity, and are necessary for an efficient CD4+ and CD8+ T cell response after infection with Mycobacterium tuberculosis (Mtb). We previously described the macrophage cell death response to Mtb infection. To investigate the effect of Mtb infection on human DC viability, we infected these phagocytes with different strains of Mtb and assessed viability, as well as DNA fragmentation and caspase activity. In parallel studies, we assessed the impact of infection on DC maturation, cytokine production and bacillary survival. Results Infection of DCs with live Mtb (H37Ra or H37Rv) led to cell death. This cell death proceeded in a caspase-independent manner, and without nuclear fragmentation. In fact, substrate assays demonstrated that Mtb H37Ra-induced cell death progressed without the activation of the executioner caspases, 3\\/7. Although the death pathway was triggered after infection, the DCs successfully underwent maturation and produced a host-protective cytokine profile. Finally, dying infected DCs were permissive for Mtb H37Ra growth. Conclusions Human DCs undergo cell death after infection with live Mtb, in a manner that does not involve executioner caspases, and results in no mycobactericidal effect. Nonetheless, the DC maturation and cytokine profile observed suggests that the infected cells can still contribute to TB immunity.

  15. Respiration shutoff in Escherichia coli K12 strains is induced by far ultraviolet radiations and by mitomycin C

    International Nuclear Information System (INIS)

    Swenson, P.A.; Norton, I.L.

    1984-01-01

    Near ultraviolet radiations (UV) cause respiration to shutoff in Escherichia coli B/r. It has been reported that E. coli K12 strains do not shut off respiration after UV. It is also reported that mitomycin C did not cause this 'SOS' response. In this paper it is reported that higher UV fluences than were previously used will cause respiration shutoff in K12 strain W3110 and that cyclic AMP increases the sensitivity of respiration shutoff of irradiated cell suspensions. Also mitomycin C shuts off respiration in this strain. Neither UV nor mitomycin C causes respiration shutoff in the recA56 derivative of W3110. Thus respiration shutoff is a recA dependent response to UV and mitomycin C in E. coli K12 strains. (Auth.)

  16. Changes in gastric microbiota induced by Helicobacter pylori infection and preventive effects of Lactobacillus plantarum ZDY 2013 against such infection.

    Science.gov (United States)

    Pan, Mingfang; Wan, Cuixiang; Xie, Qiong; Huang, Renhui; Tao, Xueying; Shah, Nagendra P; Wei, Hua

    2016-02-01

    Helicobacter pylori is a gram-negative pathogen linked to gastric ulcers and stomach cancer. Gastric microbiota might play an essential role in the pathogenesis of these stomach diseases. In this study, we investigated the preventive effect of a probiotic candidate Lactobacillus plantarum ZDY 2013 as a protective agent against the gastric mucosal inflammation and alteration of gastric microbiota induced by H. pylori infection in a mouse model. Prior to infection, mice were pretreated with or without 400 µL of L. plantarum ZDY 2013 at a concentration of 10(9) cfu/mL per mouse. At 6 wk postinfection, gastric mucosal immune response and alteration in gastric microbiota mice were examined by quantitative real-time PCR and high-throughput 16S rRNA gene amplicon sequencing, respectively. The results showed that L. plantarum ZDY 2013 pretreatment prevented increase in inflammatory cytokines (e.g., IL-1β and IFN-γ) and inflammatory cell infiltration in gastric lamina propria induced by H. pylori infection. Weighted UniFrac principal coordinate analysis showed that L. plantarum ZDY 2013 pretreatment prevented the alteration in gastric microbiota post-H. pylori infection. Linear discriminant analysis coupled with effect size identified 22 bacterial taxa (e.g., Pasteurellaceae, Erysipelotrichaceae, Halomonadaceae, Helicobacteraceae, and Spirochaetaceae) that overgrew in the gastric microbiota of H. pylori-infected mice, and most of them belonged to the Proteobacteria phylum. Lactobacillus plantarum ZDY 2013 pretreatment prevented this alteration; only 6 taxa (e.g., Lachnospiraceae, Ruminococcaceae, and Clostridiaceae), mainly from the taxa of Firmicutes and Bacteroidetes, were dominant in the gastric microbiota of the L. plantarum ZDY 2013 pretreated mice. Administration of L. plantarum ZDY 2013 for 3 wk led to increase in several bacterial taxa (e.g., Rikenella, Staphylococcus, Bifidobacterium), although a nonsignificant alteration was found in the gastric microbiota

  17. Infection-Induced Thrombin Production: A Potential Novel Mechanism for Preterm Premature Rupture of Membranes (PPROM).

    Science.gov (United States)

    Feng, Liping; Allen, Terrence K; Marinello, William P; Murtha, Amy P

    2018-04-13

    Preterm premature rupture of membranes (PPROM) is a leading contributor to maternal and neonatal morbidity and mortality. Epidemiologic and experimental studies have demonstrated that thrombin causes fetal membrane weakening and subsequently PPROM. Although blood is suspected as the likely source of thrombin in fetal membranes and amniotic fluid of patients with PPROM, this has not been proven. Ureaplasma Parvum (U. parvum) is emerging as a pathogen involved in prematurity, including PPROM, but until now, prothrombin production directly induced by bacteria in fetal membranes has not been described. This study was designed to investigate whether U. parvum exposure can induce prothrombin production in fetal membranes cells. Primary fetal membrane cells (amnion epithelial, chorion trophoblast, and decidua stromal) or full-thickness fetal membrane tissue explants from elective, term, uncomplicated cesarean deliveries were harvested. Cells or tissue explants were infected with live U. parvum (1 x 10 5 , 1 x 10 6 , or 1 x 10 7 colony forming units (cfu)/ml) or lipopolysaccharide (Escherichia coli J5, L-5014, Sigma, 100 ng/ml or 1000 ng/ml) for 24 hours. Tissue explants were fixed for immunohistochemistry staining of thrombin/prothrombin. Fetal membrane cells were fixed for confocal immunofluorescent staining of the biomarkers of fetal membrane cell types and thrombin/prothrombin. Protein and mRNA were harvested from the cells and tissue explants for Western blot or qRT-PCR to quantify thrombin/prothrombin protein or mRNA production, respectively. Data are presented as mean values ± standard errors of mean. Data were analyzed using one-way ANOVA with post hoc Dunnett's test. Prothrombin production and localization was confirmed by Western blot and immunostainings in all primary fetal membrane cells and tissue explants. Immunofluorescence observations revealed a perinuclear localization of prothrombin in amnion epithelial cells. Localization of prothrombin in chorion and

  18. Dasatinib-induced hemorrhagic colitis complicated with cytomegalovirus infection

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    Aya Nakaya

    2017-12-01

    Full Text Available A 69-year-old man with chronic-phase chronic myeloid leukemia was initially treated with 100 mg dasatinib once a day. Despite a major molecular response within 9 months, he developed hemorrhagic colitis 32 months after starting dasatinib. Colonoscopy identified multiple hemorrhagic ulcers in the transverse colon. The pathological findings indicated cytomegalovirus infection. Dasatinib was stopped and he was started on ganciclovir. Three months later, colonoscopy confirmed the disappearance of the hemorrhagic ulcers. Dasatinib is a second-generation tyrosine kinase inhibitor used to treat chronic myeloid leukemia. As a multi-kinase inhibitor that acts on SRC-family kinases, its broader off-target kinase-inhibitory activity may account for the adverse events of dasatinib. Although gastrointestinal bleeding is common in patients taking dasatinib, the combination of cytomegalovirus infection and hemorrhagic colitis in the absence of systemic immunodeficiency is rare. Based on this case of dasatinibinduced hemorrhagic colitis with cytomegalovirus infection, we describe a possible mechanism and effective treatment.

  19. Matrix metalloproteinases with gelatinolytic activity induced by Paracoccidioides brasiliensis infection

    Science.gov (United States)

    Nishikaku, Angela Satie; Ribeiro, Luciana Cristina; Molina, Raphael Fagnani Sanchez; Albe, Bernardo Paulo; Cunha, Cláudia da Silva; Burger, Eva

    2009-01-01

    Matrix metalloproteinases (MMPs) modulate extracellular matrix turnover, inflammation and immunity. We studied MMP-9 and MMP-2 in experimental paracoccidioidomycosis. At 15 and 120 days after infection (DAI) with virulent Paracoccidioides brasiliensis, MMP-9 was positive by immunohistochemistry in multinucleated giant cells, in mononuclear cells with macrophage and lymphocyte morphologies and also in fungal cells in the lesions of susceptible and resistant mice. Using gelatin zymography, pro- and active MMP-9 and active MMP-2 were detected in all infected mice, but not in controls. Gelatinolytic activity was not observed in P. brasiliensis extracts. Semiquantitative analysis of gelatinolytic activities revealed weak or absent MMP-2 and strong MMP-9 activity in both mouse strains at 15 DAI, declining at 120 DAI. Avirulent P. brasiliensis-infected mice had residual lesions with MMP-9-positive pseudoxantomatous macrophages, but no gelatinase activity at 120 DAI. Our findings demonstrate the induction of MMPs, particularly MMP-9, in experimental paracoccidioidomycosis, suggesting a possible influence in the pattern of granulomas and in fungal dissemination. PMID:19765107

  20. The effect of bacterial environmental and metabolic stresses on a laser-induced breakdown spectroscopy (LIBS) based identification of Escherichia coli and Streptococcus viridans.

    Science.gov (United States)

    Mohaidat, Qassem; Palchaudhuri, Sunil; Rehse, Steven J

    2011-04-01

    In this paper we investigate the effect that adverse environmental and metabolic stresses have on the laser-induced breakdown spectroscopy (LIBS) identification of bacterial specimens. Single-pulse LIBS spectra were acquired from a non-pathogenic strain of Escherichia coli cultured in two different nutrient media: a trypticase soy agar and a MacConkey agar with a 0.01% concentration of deoxycholate. A chemometric discriminant function analysis showed that the LIBS spectra acquired from bacteria grown in these two media were indistinguishable and easily discriminated from spectra acquired from two other non-pathogenic E. coli strains. LIBS spectra were obtained from specimens of a nonpathogenic E. coli strain and an avirulent derivative of the pathogen Streptococcus viridans in three different metabolic situations: live bacteria reproducing in the log-phase, bacteria inactivated on an abiotic surface by exposure to bactericidal ultraviolet irradiation, and bacteria killed via autoclaving. All bacteria were correctly identified regardless of their metabolic state. This successful identification suggests the possibility of testing specimens that have been rendered safe for handling prior to LIBS identification. This would greatly enhance personnel safety and lower the cost of a LIBS-based diagnostic test. LIBS spectra were obtained from pathogenic and non-pathogenic bacteria that were deprived of nutrition for a period of time ranging from one day to nine days by deposition on an abiotic surface at room temperature. All specimens were successfully classified by species regardless of the duration of nutrient deprivation. © 2011 Society for Applied Spectroscopy

  1. Expression of the major outer membrane protein (MOMP) of Chlamydophila abortus, Chlamydophila pecorum, and Chlamydia suis in Escherichia coli using an arabinose-inducible plasmid vector.

    Science.gov (United States)

    Hoelzle, L E; Hoelzle, K; Wittenbrink, M M

    2003-10-01

    The ompA genes encoding the 40 kDa major outer membrane protein (MOMP) of Chlamydophila (Ch.) abortus, Ch. pecorum, and Chlamydia (C.) suis were cloned into the arabinose-inducible plasmid vector pBADMycHis, and recombinant MOMPs (rMOMP) from the three chlamydial species were expressed at high levels in Escherichia (E.) coli. The proteins lacking the 22 aa N-terminal signal peptide were expressed as insoluble cytoplasmic inclusion bodies which were readily purified using immobilized metal-affinity chromatography. The rMOMPs including the N-terminal signal peptide were expressed and translocated as a surface-exposed immunoaccessible protein into the outer membrane of E. coli. Transformants expressing this full-length rMOMP were significantly reduced in viability. Purified native elementary bodies (EB) and rMOMPs of the three chlamydial species purified from the E. coli cytoplasm were used for immunization of rabbits. The resulting sera were analysed for their ability to recognize homologous and heterologous rMOMP and native EB. When testing rMOMP antisera against rMOMP and EB antigens, marked cross-reactivities were detected between the three species. Using EB antisera and rMOMPs as antigens, a significant species-specific reactivity was measured.

  2. Effect of RNase E deficiency on translocon protein synthesis in an RNase E-inducible strain of enterohemorrhagic Escherichia coli O157:H7.

    Science.gov (United States)

    Lodato, Patricia B; Thuraisamy, Thujitha; Richards, Jamie; Belasco, Joel G

    2017-07-06

    Enterohemorrhagic Escherichia coli (EHEC) is a food-borne pathogen that assembles a type III secretion system (T3SS) on its surface. The last portion of the T3SS, called the 'translocon', is composed of a filament and a pore complex that is inserted into the membrane of intestinal epithelial cells. The genes encoding the translocon (espADB) are part of the LEE4 operon. Their expression is regulated by a complex post-transcriptional mechanism that involves the processing of LEE4 mRNA by the essential endoribonuclease RNase E. Here, we report the construction of an EHEC strain (TEA028-rne) in which RNase E can be induced by adding IPTG to the culture medium. EHEC cells deficient in RNase E displayed an abnormal morphology and slower growth, in agreement with published observations in E. coli K-12. Under those conditions, EspA and EspB were produced at higher concentrations, and protein secretion still occurred. These results indicate that RNase E negatively regulates translocon protein synthesis and demonstrate the utility of E. coli strain TEA028-rne as a tool for investigating the influence of this ribonuclease on EHEC gene expression in vitro. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Influence of some exo nucleases in response to the induced genetic damage in Escherichia coli by alpha radiation

    International Nuclear Information System (INIS)

    Aguilar M, M.

    2005-01-01

    Within the strategies with those that E. coli counts to overcome to the genetic damage there is the SOS response, a group of genes that participate in repair and/or tolerance that it confers to the bacteria major opportunities of surviving. These genes are repressed and its only are expressed when it happens genetic damage. So that this system is activated it is necessary that DNA of a band exists and in this sense the double ruptures (RDB) its are not able to induce this response unless there is a previous processing. In stumps with defects in certain genes that have to do with repair of RDB (as recO, recJ and xonA) the activity of SOS is smaller than in a wild stump what suggests that these participate in the previous processes to the activation of the response. The ionizing radiation produce among other many lesions, RDB in greater or smaller proportion, depending on the ionization capacity. A parameter to evaluate this capacity is the lineal energy transfer (LET), defined as the average energy given by unit of distance travelled. In general the LET of the corpuscular radiations is a lot but high that of the electromagnetic one, for what produces bigger quantity of ionizations inside a restricted zone and it increases by this way the probability that RDB has been generated. This work has for object to infer the participation of xonA and recJ in this response and to evaluate the damage produced by ionizing radiation of different LET (alpha particles of different energies) in a stump with all the functional repair mechanisms. Its were considered two parameters: the survival and the activity of SOS evaluated by means of the chromo test. The results indicate that the activity of these exo nucleases is necessary for the repair of RDB as well as for the processing of lesions foresaw to the activation of SOS. As for the treatment with alphas of different energies is observed that so much the survival like the activity of SOS vary as the LET of the radiation changes

  4. N-acylated peptides derived from human lactoferricin perturb organization of cardiolipin and phosphatidylethanolamine in cell membranes and induce defects in Escherichia coli cell division.

    Directory of Open Access Journals (Sweden)

    Dagmar Zweytick

    Full Text Available Two types of recently described antibacterial peptides derived from human lactoferricin, either nonacylated or N-acylated, were studied for their different interaction with membranes of Escherichia coli in vivo and in model systems. Electron microscopy revealed striking effects on the bacterial membrane as both peptide types induced formation of large membrane blebs. Electron and fluorescence microscopy, however demonstrated that only the N-acylated peptides partially induced the generation of oversized cells, which might reflect defects in cell-division. Further a different distribution of cardiolipin domains on the E. coli membrane was shown only in the presence of the N-acylated peptides. The lipid was distributed over the whole bacterial cell surface, whereas cardiolipin in untreated and nonacylated peptide-treated cells was mainly located at the septum and poles. Studies with bacterial membrane mimics, such as cardiolipin or phosphatidylethanolamine revealed that both types of peptides interacted with the negatively charged lipid cardiolipin. The nonacylated peptides however induced segregation of cardiolipin into peptide-enriched and peptide-poor lipid domains, while the N-acylated peptides promoted formation of many small heterogeneous domains. Only N-acylated peptides caused additional severe effects on the main phase transition of liposomes composed of pure phosphatidylethanolamine, while both peptide types inhibited the lamellar to hexagonal phase transition. Lipid mixtures of phosphatidylethanolamine and cardiolipin revealed anionic clustering by all peptide types. However additional strong perturbation of the neutral lipids was only seen with the N-acylated peptides. Nuclear magnetic resonance demonstrated different conformational arrangement of the N-acylated peptide in anionic and zwitterionic micelles revealing possible mechanistic differences in their action on different membrane lipids. We hypothesized that both peptides kill

  5. Effects of the umuC36 mutation on ultraviolet-radiation-induced base-change and frameshift mutations in Escherichia coli

    International Nuclear Information System (INIS)

    Kato, T.; Nakano, E.

    1981-01-01

    The effects of the umuC36 mutation on the induction of base-change and frameshift mutations were studied. An active umuC gene was necessary in either the uvr + or uvr - strains of Escherichia coli K12 for UV- and X-ray-induced mutations to His + , ColE and Spc, which are presumably base-change mutations, but it was not essential for ethyl methanesulphonate or N-methyl-N'-nitro-N-nitrosoguanidine-induced His + mutations. In contrast, only 1 out of 13 trp - frameshift mutations examined was UV reversible, and the process of mutagenesis was umuC + -dependent, whereas a potent frameshift mutagen, ICR191, effectively induced Trp + mutations in most of the strains regardless of the umu + or umuC genetic background. These results suggest that base substitutions are a major mutational type derived from the umuC + -dependent pathway of error-prone repair. (orig.)

  6. Legionella pneumophila infection of Drosophila S2 cells induces only minor changes in mitochondrial dynamics.

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    Elizabeth Wen Sun

    Full Text Available During infection of cells by Legionella pneumophila, the bacterium secretes a large number of effector proteins into the host cell cytoplasm, allowing it to alter many cellular processes and make the vacuole and the host cell into more hospitable environments for bacterial replication. One major change induced by infection is the recruitment of ER-derived vesicles to the surface of the vacuole, where they fuse with the vacuole membrane and prevent it from becoming an acidified, degradative compartment. However, the recruitment of mitochondria to the region of the vacuole has also been suggested by ultrastructural studies. In order to test this idea in a controlled and quantitative experimental system, and to lay the groundwork for a genome-wide screen for factors involved in mitochondrial recruitment, we examined the behavior of mitochondria during the early stages of Legionella pneumophila infection of Drosophila S2 cells. We found that the density of mitochondria near vacuoles formed by infection with wild type Legionella was not different from that found in dotA(- mutant-infected cells during the first 4 hours after infection. We then examined 4 parameters of mitochondrial motility in infected cells: velocity of movement, duty cycle of movement, directional persistence and net direction. In the 4 hours following infection, most of these measures were indistinguishable between wild type and dotA(-.infection. However, wild type Legionella did induce a modest shift in the velocity distribution toward faster movement compared dotA(- infection, and a small downward shift in the duty cycle distribution. In addition, wild type infection produced mitochondrial movement that was biased in the direction of the bacterial vacuole relative to dotA-, although not enough to cause a significant accumulation within 10 um of the vacuole. We conclude that in this host cell, mitochondria are not strongly recruited to the vacuole, nor is their motility

  7. Colistin- and Carbapenem-Resistant Escherichia coli Harboring mcr-1 and blaNDM-5, Causing a Complicated Urinary Tract Infection in a Patient from the United States

    Directory of Open Access Journals (Sweden)

    José R. Mediavilla

    2016-08-01

    Full Text Available Colistin is increasingly used as an antibiotic of last resort for the treatment of carbapenem-resistant Gram-negative infections. The plasmid-borne colistin resistance gene mcr-1 was initially identified in animal and clinical samples from China and subsequently reported worldwide, including in the United States. Of particular concern is the spread of mcr-1 into carbapenem-resistant bacteria, thereby creating strains that approach pan-resistance. While several reports of mcr-1 have involved carbapenem-resistant strains, no such isolates have been described in the United States. Here, we report the isolation and identification of an Escherichia coli strain harboring both mcr-1 and carbapenemase gene blaNDM-5 from a urine sample in a patient without recent travel outside the United States. The isolate exhibited resistance to both colistin and carbapenems, but was susceptible to amikacin, aztreonam, gentamicin, nitrofurantoin, tigecycline, and trimethoprim-sulfamethoxazole. The mcr-1- and blaNDM-5-harboring plasmids were completely sequenced and shown to be highly similar to plasmids previously reported from China. The strain in this report was first isolated in August 2014, highlighting an earlier presence of mcr-1 within the United States than previously recognized.

  8. Increased number of intestinal villous M cells in levamisole - pretreated weaned pigs experimentally infected with F4ac+ enterotoxigenic Escherichia coli strain

    Directory of Open Access Journals (Sweden)

    H. Valpotić

    2010-07-01

    Full Text Available Immunoprophylaxis of porcine postweaning colibacillosis (PWC caused by enterotoxigenic Escherichia coli (ETEC expressing F4 fimbriae is an unsolved problem. Just as ETEC strains can exploit intestinal microfold (M cells as the entry portal for infection, their high transcytotic ability make them an attractive target for mucosally delivered vaccines, adjuvants and therapeutics. We have developed a model of parenteral/oral immunization of 4-weeks-old pigs with either levamisole or vaccine candidate F4ac+ non-ETEC strain to study their effects on de novo differentiation of antigen-sampling M cells. Identification, localization and morphometric quantification of cytokeratin 18 positive M cells in the ileal mucosa of 6-weeks-old pigs revealed that they were: 1 exclusively located within villous epithelial layer, 2 significantly numerous (P< 0.01 in levamisole pretreated/challenged pigs, and 3 only slightly, but not significantly numerous in vaccinated/challenged pigs compared with non-pretreated/challenged control pigs. The fact that levamisole may affect the M cells frequency by increasing their numbers, makes it an interesting adjuvant to study development of an effective M cell-targeted vaccine against porcine PWC.

  9. Fusarium solani Infection Depressed Photosystem Performance by Inducing Foliage Wilting in Apple Seedlings

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    Kun Yan

    2018-05-01

    Full Text Available Fusarium fungi are soil-borne pathogens, and the pathological effects on plant photosystems remain unclear. This study aimed to deeply reveal pathological characterization in apple seedlings infected with Fusariu