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Enterotoxigenic Escherichia coli - an overview
Guth, Beatriz Ernestina Cabilio;
Memórias do Instituto Oswaldo Cruz , 2000, DOI: 10.1590/S0074-02762000000700017
Abstract: enterotoxigenic escherichia coli is an important cause of traveler's diarrhea and diarrheal illnesses in children in the developing world. in this presentation we will focus on the main virulence attributes of this pathogenic category of e. coli, and discuss the evolution of studies conducted in our laboratory.
Enterotoxigenic Escherichia coli - an overview  [cached]
Guth Beatriz Ernestina Cabilio
Memórias do Instituto Oswaldo Cruz , 2000,
Abstract: Enterotoxigenic Escherichia coli is an important cause of traveler's diarrhea and diarrheal illnesses in children in the developing world. In this presentation we will focus on the main virulence attributes of this pathogenic category of E. coli, and discuss the evolution of studies conducted in our laboratory.
Antimicrobial activity of essential oils against Vancomycin-Resistant enterococci (VRE) and Escherichia coli O157:H7 in feta soft cheese and minced beef meat
Selim, Samy;
Brazilian Journal of Microbiology , 2011, DOI: 10.1590/S1517-83822010005000005
Abstract: eleven essential oils (eos) were evaluated for their antibacterial properties, against vancomycin-resistant enterococci (vre) and e. coli o157:h7. eos were introduced into brain heart infusion agar (bhi) (15ml) at a concentration of 0.25 to 2% (vol/vol) to determine the minimum inhibitory concentration (mic) and minimum bactericidal concentration (mbc) for each pathogen evaluated. results showed that the most active essential oils against bacteria tested were thyme oil, with mic90 and mbc90 for the vra strains of 0.25% and 0.5%, respectively. eucalyptus, juniper and clove oils were the least potent agent, with mic90 and mbc90 of 2%. furthermore, the inhibitory effect of these eo were evaluated against vre and e. coli o157:h7, experimentally inoculated (103 cfu/g) in feta soft cheese and minced beef meat, which was mixed with different concentrations (0.1%, 0.5% and 1%) of the eo and stored at 7 oc for 14 days. out of eucalyptus, juniper, mint, rosemary, sage, clove and thyme oils tested against target bacteria sage and thyme showed the best results. clove and mint did not show any effect on vre and e. coli o157:h7 in both kinds of studied foods. the addition of thyme oil at concentrations of 0.5 and 1% caused best significant reduction in the growth rate of vre and e. coli o157:h7 in cheese and meat at 7 oc. it is concluded that selected plant eos can act as potent inhibitors of both microorganisms in a food product. the results revealed the potential of thyme oil as a natural preservative in feta soft cheese and minced beef meat against vre and e. coli o157:h7 contamination.
Prevalence of enteropathogenic and enterotoxigenic Escherichia Coli in foods of animal origin in southern Brazil
Aleixo, José Antonio;Aver, Gladis Paim;
Ciência Rural , 1996, DOI: 10.1590/S0103-84781996000200013
Abstract: prevalence of escherichia coli in foods of animal origin from the city of pelotas, brazil, was determined. the ocurrence of enterotoxigenic (etec) and classic enteropathogenic (epec) serogroups among e. coli isolates was determined. e. coli was isolated from 68% of the food samples surveyed. of 36 food samples tested, 11(30%) and 24(66%) were positive for epec and etec strains respectively. however, of 187 e. coli isolates tested, 30(16%) were epec compared to 75(40%) which were etec. the antibiotic resistance pattern revealed that the isolates were highly sensitive to all antibiotics tested.
Capture immunoassay for LT detection produced by enterotoxigenic Escherichia coli in bacterial isolates
Menezes, Caroline Anuncia??o;Gon?alves, Danielle Silva;Amianti, Jackeline;Fernandes, Irene;Taddei, Carla Romano;Koga, Paula Célia Mariko;Trabulsi, Luiz Rachid;Martinez, Marina Baquerizo;Piazza, Roxane Maria Fontes;
Brazilian Journal of Microbiology , 2003, DOI: 10.1590/S1517-83822003000500004
Abstract: a capture enzyme-linked immunosorbent assay (elisa), which detects lt-i toxin produced by enterotoxigenic escherichia coli strains, has been developed. this capture assay was performed using the igg enriched fraction of anti-lt-i antiserum and igg2b anti-lt-i monoclonal antibody and allowed a clear distinction between e. coli lt-i - producing and non-producing strains. the estimated accuracy of the assay is 78% for sensitivity, 94% for specificity and 92% for efficiency. thus, the capture immunoassay is a sensitive tool for detection of e. coli, which produces heat-labile enterotoxin, and is suitable for use in clinical laboratories and epidemiological surveys in developing world.
Antibiotic resistance of enterotoxigenic and entroaggrigative Escherichia coli isolated from gastroenteritis cases  [cached]
Barati S
Asian Journal of Biomedical and Pharmaceutical Sciences , 2012,
Abstract: Background: Toxigenic strains of Escherichia coli are common enteric pathogens of human. The aim of this study was to detect virulence genes and antibiotic resistance pattern of the enterotoxigenic and enteroaggrigative E. coli isolated from diarhoeal stool samples.Methods: Totally, 234 diarrhoeal stool samples were collected. Microbiological examinations were done to detect the E. coli. PCR was used to identify Lt, Sta, Stb and East1 genes. Antibiotic resistance test was performed using the Disk diffusion method. Results: Out of 114 isolated E. coli, 15(13.5%) harbored Stb, 52(45.61%) East1, 30 (26.31%) Lt gene. The Sta gene was not detected in tested samples. The lowest resistance was for gentamicin (0%) while the highest resistance was for trimethoprim (79.8%). Resistance of E. coli isolates to chloramphenicol, cephotaxime, sulphametoxazole, ciprofloxacin, ampicillin and tetracycline were 3.5%, 7.01%, 71.05%, 10.5%, 52.63% and 3.5%, respectively. Conclusions: Toxigenic E. coli strains perticipated in diarrhoea in Shahrekord-Iran. The high presences of antibiotic resistance have been shown to trimethoprim, sulphametoxazole and ampicillin
Structure and function of Enterotoxigenic Escherichia coli fimbriae from differing assembly pathways  [PDF]
Narges Mortezaei,Chelsea R. Epler,Paul P. Shao,Mariam Shirdel,Bhupender Singh,Annette McVeigh,Bernt Eric Uhlin,Stephen J. Savarino,Magnus Andersson,Esther Bullitt
Quantitative Biology , 2014, DOI: 10.1111/mmi.12847/
Abstract: Pathogenic enterotoxigenic Escherichia coli (ETEC) are the major bacterial cause of diarrhea in young children in developing countries and in travelers, causing significant mortality in children. Adhesive fimbriae are a prime virulence factor for ETEC, initiating colonization of the small intestinal epithelium. Similar to other Gram-negative bacteria, ETEC express one or more diverse fimbriae, some assembled by the chaperone-usher pathway and others by the alternate chaperone pathway. Here we elucidate structural and biophysical aspects and adaptations of each fimbrial type to its respective host niche. CS20 fimbriae are compared to CFA/I fimbriae, which are two ETEC fimbriae assembled via different pathways, and to Pfimbriae from uropathogenic E. coli. Many fimbriae unwind from their native helical filament to an extended linear conformation under force, thereby sustaining adhesion by reducing load at the point of contact between the bacterium and the target cell. CFA/I fimbriae require the least force to unwind, followed by CS20 fimbriae and then P-fimbriae, which require the highest unwinding force. We conclude from our electron microscopy reconstructions, modeling, and force spectroscopy data that the target niche plays a central role in the biophysical properties of fimbriae that are critical for bacterial pathophysiology.
Directed Evaluation of Enterotoxigenic Escherichia coli Autotransporter Proteins as Putative Vaccine Candidates  [PDF]
Jessica A. Harris equal contributor,Koushik Roy equal contributor,Virginia Woo-Rasberry,David J. Hamilton,Rita Kansal,Firdausi Qadri,James M. Fleckenstein
PLOS Neglected Tropical Diseases , 2011, DOI: 10.1371/journal.pntd.0001428
Abstract: Background Enterotoxigenic Escherichia coli (ETEC) is a major diarrheal pathogen in developing countries, where it accounts for millions of infections and hundreds of thousands of deaths annually. While vaccine development to prevent diarrheal illness due to ETEC is feasible, extensive effort is needed to identify conserved antigenic targets. Pathogenic Escherichia coli, including ETEC, use the autotransporter (AT) secretion mechanism to export virulence factors. AT proteins are comprised of a highly conserved carboxy terminal outer membrane beta barrel and a surface-exposed amino terminal passenger domain. Recent immunoproteomic studies suggesting that multiple autotransporter passenger domains are recognized during ETEC infection prompted the present studies. Methodology Available ETEC genomes were examined to identify AT coding sequences present in pathogenic isolates, but not in the commensal E. coli HS strain. Passenger domains of the corresponding autotransporters were cloned and expressed as recombinant antigens, and the immune response to these proteins was then examined using convalescent sera from patients and experimentally infected mice. Principal Findings Potential AT genes shared by ETEC strains, but absent in the E. coli commensal HS strain were identified. Recombinant passenger domains derived from autotransporters, including Ag43 and an AT designated pAT, were recognized by antibodies from mice following intestinal challenge with H10407, and both Ag43 and pAT were identified on the surface of ETEC by flow cytometry. Likewise, convalescent sera from patients with ETEC diarrhea recognized Ag43 and pAT, suggesting that these proteins are expressed during both experimental and naturally occurring ETEC infections and that they are immunogenic. Vaccination of mice with recombinant passenger domains from either pAT or Ag43 afforded protection against intestinal colonization with ETEC. Conclusions Passenger domains of conserved autotransporter proteins could contribute to protective immune responses that develop following infection with ETEC, and these antigens consequently represent potential targets to explore in vaccine development.
Serum Antibodies Protect against Intraperitoneal Challenge with Enterotoxigenic Escherichia coli
Xinghong Yang,Theresa Thornburg,Kathryn Holderness,Zhiyong Suo,Ling Cao,Timothy Lim,Recep Avci,David W. Pascual
Journal of Biomedicine and Biotechnology , 2011, DOI: 10.1155/2011/632396
Abstract: To assess whether anticolonization factor antigen I (CFA/I) fimbriae antibodies (Abs) from enterotoxigenic Escherichia coli (ETEC) can protect against various routes of challenge, BALB/c mice were immunized with a live attenuated Salmonella vaccine vector expressing CFA/I fimbriae. Vaccinated mice elicited elevated systemic IgG and mucosal IgA Abs, unlike mice immunized with the empty Salmonella vector. Mice were challenged with wild-type ETEC by the oral, intranasal (i.n.), and intraperitoneal (i.p.) routes. Naïve mice did not succumb to oral challenge, but did to i.n. challenge, as did immunized mice; however, vaccinated mice were protected against i.p. ETEC challenge. Two intramuscular (i.m.) immunizations with CFA/I fimbriae without adjuvant conferred 100% protection against i.p. ETEC challenge, while a single 30 μg dose conferred 88% protection. Bactericidal assays showed that ETEC is highly sensitive to anti-CFA/I sera. These results suggest that parenteral immunization with purified CFA/I fimbriae can induce protective Abs and may represent an alternative method to elicit protective Abs for passive immunity to ETEC.
Protective Enterotoxigenic Escherichia coli Antigens in a Murine Intranasal Challenge Model  [PDF]
Amit Kumar?,Mike Hays?,Francis Lim?,Leonard J. Foster?,Mingxu Zhou?,Guoqiang Zhu?,Tracy Miesner?,Philip R. Hardwidge
PLOS Neglected Tropical Diseases , 2015, DOI: 10.1371/journal.pntd.0003924
Abstract: Enterotoxigenic Escherichia coli (ETEC) is an endemic health threat in underdeveloped nations. Despite the significant effort extended to vaccine trials using ETEC colonization factors, these approaches have generally not been especially effective in mediating cross-protective immunity. We used quantitative proteomics to identify 24 proteins that differed in abundance in membrane protein preparations derived from wild-type vs. a type II secretion system mutant of ETEC. We expressed and purified a subset of these proteins and identified nine antigens that generated significant immune responses in mice. Sera from mice immunized with either the MltA-interacting protein MipA, the periplasmic chaperone seventeen kilodalton protein, Skp, or a long-chain fatty acid outer membrane transporter, ETEC_2479, reduced the adherence of multiple ETEC strains differing in colonization factor expression to human intestinal epithelial cells. In intranasal challenge assays of mice, immunization with ETEC_2479 protected 88% of mice from an otherwise lethal challenge with ETEC H10407. Immunization with either Skp or MipA provided an intermediate degree of protection, 68 and 64%, respectively. Protection was significantly correlated with the induction of a secretory immunoglobulin A response. This study has identified several proteins that are conserved among heterologous ETEC strains and may thus potentially improve cross-protective efficacy if incorporated into future vaccine designs.
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