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

Science.gov (United States)

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

2004-01-01

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

Screening for virulence genes in Escherichia coli O157:H7 obtained ...

African Journals Online (AJOL)

Eighty (80) sources of drinking water comprising boreholes (24), streams (3), wells (29), pipe-borne (5) and 19 sachet water samples were collected between March 2014 and February 2015. Escherichia coli (E.coli) O157:H7 was isolated by enrichment in Tryptone soy broth at elevated temperature and streaking on Eosin ...

Structure and genetics of the O-specific polysaccharide of Escherichia coli O27.

Science.gov (United States)

Perepelov, Andrei V; Chen, Tingting; Senchenkova, Sofya N; Filatov, Andrei V; Song, Jingjie; Shashkov, Alexander S; Liu, Bin; Knirel, Yuriy A

2018-02-01

The O-specific polysaccharide (O-antigen) is a part of the lipopolysaccharide on the cell surface of Gram-negative bacteria. The O-polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide of Escherichia coli O27 and studied by sugar analysis and Smith degradation along with 1 H and 13 C NMR spectroscopy. The following structure of the branched hexasaccharide repeating unit was established, which is unique among known structures of bacterial polysaccharides:where GlcA is non-stoichiometrically O-acetylated at position 3 (∼22%) or 4 (∼37%). Functions of genes in the O-antigen gene cluster of E. coli O27 were tentatively assigned by comparison with sequences in the available databases and found to be consistent with the O-polysaccharide structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Genomic Variability of O Islands Encoding Tellurite Resistance in Enterohemorrhagic Escherichia coli O157:H7 Isolates

OpenAIRE

Taylor, Diane E.; Rooker, Michelle; Keelan, Monika; Ng, Lai-King; Martin, Irene; Perna, Nicole T.; Burland, N. T. Valerie; Blattner, Fredrick R.

2002-01-01

Strains of Escherichia coli causing enterohemorrhagic colitis belonging to the O157:H7 lineage are reported to be highly related. Fifteen strains of E. coli O157:H7 and 1 strain of E. coli O46:H− (nonflagellated) were examined for the presence of potassium tellurite resistance (Ter). Ter genes comprising terABCDEF were shown previously to be part of a pathogenicity island also containing integrase, phage, and urease genes. PCR analysis, both conventional and light cycler based, demonstrated t...

Primer aislamiento de Escherichia coli O157:H7 Enterohemorrágica en el Perú

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Blanca Huapaya C

2001-01-01

Full Text Available En Febrero del año 2001 como parte del "Estudio transversal de los agentes etiológicos de diarrea aguda" en la Macrorregión Sur del país, el Laboratorio Referencial de Tacna aisló una cepa procedente de una muestra de heces de un lactante de 11 meses de edad con un cuadro de diarrea disentérica, identificándola como Escherichia coli O157. Esta cepa fue confirmada y caracterizada en el Instituto Nacional de Salud como E. coli O157:H7 toxina shiga tipo II, siendo el primer aislamiento reportado de Escherichia coli enterohemorrágica en el Perú.

Microbiota response to Escherichia coli O157:H7 colonization in cattle

Science.gov (United States)

Cattle are primary reservoir of Shiga toxin-producing Escherichia coli (STEC). Field studies indicate STEC colonization influences gut microbiota composition in beef and dairy cattle. In this pilot study, we evaluated the bovine gut microbiota after STEC O157 (O157) challenge under experimental con...

Identificação de cepas de Escherichia coli enteropatogênicas em amostras de fezes, por reação de imunofluorescência direta Identification of strains of Escherichia coli in stool samples by direct fluorescent antibody tests

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Ieda Maria Longo

1980-06-01

Full Text Available Foi realizado diagnóstico etiológico de casos de diarréia aguda em 121 pacientes internados na Clínica Pediátrica do Hospital da Santa Casa de São Paulo, Brasil. Foram utilizados os métodos bacteriológico clássico e de reação de imunofluorescência direta para a identificação de cepas de Escherichia coli enteropatogênicas: para estudo da sensibilidade das cepas de Escherichia coli isoladas, a diferentes antibióticos, foi usado o método de Concentração Inibitória Minima (CIM. Dos 56 casos positivos, 89,3% correspondiam a diferentes sorotipos enteropatogênicos de Escherichia coli, quando utilizada a técnica de imunofluorescência direta. O método bacteriológico clássico revelou ainda, nos 121 casos examinados, 4 cepas de Salmonella e 2 de Shigella. No estudo da CIM verificou-se maior sensibilidade das cepas de Escherichia coli enteropatogênicas estudadas à Gentamicina e Amikacina, do que aos outros antibióticos.A study of 121 patients with acute diarrhea was made at the Pediatric Clinic of the Santa Casa de S. Paulo (the S. Paulo Charity Hospital. Etiological diagnosis of 121 cases was carried out through the classical bacteriological method and direct fluorescent antibody tests for the identification of E. coli. The antibiotic sensitivity of these bacteria to different antimicrobials was determined by the Minimum Inhibitory Concentration (MIC method. Fifty-six positive cases were found; 89.3% of which corresponded to different serotypes of enter o pathogenic E. coli (89.3%, when the direct fluorescent antibody test was used. The classic bacteriological method bared four Salmonella strains and two Shigella. The MIC showed the E. coli to be more sensitive to Gentamicin and Amikacin than to other antibiotics.

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

Science.gov (United States)

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

2017-01-01

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

Antibiotic susceptibility-resistance profiles of super-shed Escherichia coli O157:H7

Science.gov (United States)

Introduction: Escherichia coli O157:H7 (O157) can cause diarrhea and serious secondary sequelae including kidney failure and death in humans. With antibiotics like fosfomycin, colistin and azithromycin, that do not stimulate toxin expression by O157, being considered for treatment of early gastroint...

Contaminated Stream Water as Source for Escherichia coli O157 Illness in Children.

Science.gov (United States)

Probert, William S; Miller, Glen M; Ledin, Katya E

2017-07-01

In May 2016, an outbreak of Shiga toxin-producing Escherichia coli O157 infections occurred among children who had played in a stream flowing through a park. Analysis of E. coli isolates from the patients, stream water, and deer and coyote scat showed that feces from deer were the most likely source of contamination.

Characterization of the YdeO regulon in Escherichia coli.

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Yuki Yamanaka

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

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

African Journals Online (AJOL)

PRECIOUS

2010-01-11

Jan 11, 2010 ... source of water for large scale fresh produce irrigation and herd .... Duncan's multiple range tests were used to compare the means of parameters for the .... Longitudinal study of faecal shedding of Escherichia coli O157: H7 in.

Towards a Molecular Definition of Enterohemorrhagic Escherichia coli (EHEC): Detection of Genes Located on O Island 57 as Markers To Distinguish EHEC from Closely Related Enteropathogenic E. coli Strains

Science.gov (United States)

Delannoy, Sabine; Beutin, Lothar

2013-01-01

Among strains of Shiga-toxin (Stx) producing Escherichia coli (STEC), seven serogroups (O26, O45, O103, O111, O121, O145, and O157) are associated with severe clinical illness in humans. These strains are also called enterohemorrhagic E. coli (EHEC), and the development of methods for their reliable detection from food has been challenging thus far. PCR detection of major EHEC virulence genes stx1, stx2, eae, and O-serogroup-specific genes is useful but does not identify EHEC strains specifically. Searching for the presence of additional genes issued from E. coli O157:H7 genomic islands OI-122 and OI-71 increases the specificity but does not clearly discriminate EHEC from enteropathogenic E. coli (EPEC) strains. Here, we identified two putative genes, called Z2098 and Z2099, from the genomic island OI-57 that were closely associated with EHEC and their stx-negative derivative strains (87% for Z2098 and 91% for Z2099). Z2098 and Z2099 were rarely found in EPEC (10% for Z2098 and 12% for Z2099), STEC (2 and 15%), and apathogenic E. coli (1% each) strains. Our findings indicate that Z2098 and Z2099 are useful genetic markers for a more targeted diagnosis of typical EHEC and new emerging EHEC strains. PMID:23325824

CHARACTERIZATION AND ANTIBIOGRAM OF ENTEROPATHOGENIC ESCHERICHIA COLI ISOLATED FROM POULTRY

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M. Sarkar

2013-12-01

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

Enterohemorrhagic Escherichia coli (EHEC

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Abdullah Kilic

2011-08-01

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

Temperature-Dependent Fermentation of d-Sorbitol in Escherichia coli O157:H7

OpenAIRE

Bouvet, O. M. M.; Pernoud, S.; Grimont, P. A. D.

1999-01-01

The influence of growth temperature on the ability to ferment d-sorbitol was investigated in Escherichia coli O157:H7. It was found that O157:H7 strains have a temperature-sensitive sorbitol phenotype. d-Sorbitol transport and sorbitol-6-phosphate dehydrogenase activities were expressed in sorbitol-fermenting cells grown at 30°C but only at a low level at 40°C. Sorbitol-positive variants able to transport d-sorbitol were easily selected at 30°C from culture of Sor− E. coli O157:H7 strains.

77 FR 58091 - Risk-Based Sampling of Beef Manufacturing Trimmings for Escherichia coli (E. coli) O157:H7 and...

Science.gov (United States)

2012-09-19

... for exposure of carcasses and parts to any contamination or food safety hazard during the removal of... DEPARTMENT OF AGRICULTURE Food Safety and Inspection Service [Docket No. FSIS-2012-0020] Risk-Based Sampling of Beef Manufacturing Trimmings for Escherichia coli (E. coli) O157:H7 and Plans for Beef...

Proliferation of Escherichia coli O157:H7 in soil and hydroponic microgreen production systems

Science.gov (United States)

Radish (Raphanus sativus var. longipinnatus) microgreens were produced from seeds inoculated with Escherichia coli O157: H7 using soil substitute and hydroponic production systems. E. coli populations on the edible and inedible parts of harvested microgreen plants and in growth medium were examined....

Phylogenetische und funktionelle Analysen zur Kapsel O-Acetyltransferase NeuO von Escherichia coli K1

OpenAIRE

Mordhorst, Ines Louise

2010-01-01

Escherichia coli ist ein Kommensale des menschlichen und tierischen Gastrointestinaltraktes. Einige E. coli-Stämme sind in der Lage, extraintestinale Erkrankungen beim Menschen wie Harnwegsinfekte, Neugeborenen-Meningitis und Sepsis, sowie beim Tier aviäre Coliseptikämien, hervorzurufen. Ein wichtiger Virulenzfaktor des Bakteriums ist dabei die aus α-2,8-verknüpften Sialinsäuremonomeren aufgebaute K1-Kapsel, die phasenvariabel mit einer hohen Frequenz O-acetyliert werden kann. Im Jahr 20...

Combined effect of ultrasound, heat, and pressure on Escherichia coli O157:H7, polyphenol oxidase activity, and anthocyanins in blueberry (Vaccinium corymbosum) juice.

Science.gov (United States)

Zhu, Jinyan; Wang, Yuehua; Li, Xinghe; Li, Bin; Liu, Suwen; Chang, Nan; Jie, Ding; Ning, Chong; Gao, Haiyan; Meng, Xianjun

2017-07-01

The objective of this study was to evaluate the effect of different treatments-heat treatment (HT), sonication (SC), thermosonication (TS), manosonication (MS), manothermal (MT), and manothermosonication (MTS) on Escherichia coli O157:H7, polyphenol oxidase (PPO), and anthocyanin content in blueberry juice. First, samples were treated at different temperatures (30, 40, 50, 60, 70, and 80°C) and power intensities (280, 420, 560, and 700W) for 10min. Subsequently, samples were treated using combinations of power intensity and mild temperature for 10min. For further study, samples were treated using HT (80°C), TS (40°C, 560W), MT (350MPa, 40°C), MS (560W, 5min/350MPa), or MTS (560W, 5min, 40°C/350MPa, 40°C) for 5, 10, 15, 20min for each treatment, and the results compared between treatments. HT significantly reduced PPO activation (2.05% residual activity after only 5min), and resulted in a 2.00-log reduction in E. coli O157:H7 and an 85.25% retention of anthocyanin. Escherichia coli O157:H7 was slightly inactivated by TS after 5min (0.17-log reduction), while residual PPO activity was 23.36% and anthocyanin retention was 98.48%. However, Escherichia coli O157:H7 was rapidly inactivated by MTS (5.85-log reduction) after 5min, while anthocyanin retention was 97.49% and residual PPO activity dropped to 10.91%. The destruction of E. coli cells as a result of these treatments were confirmed using SEM and TEM. Therefore, a combination of sonication, high pressure, and mild heat allows the safety of blueberry juice to be maintained without compromising the retention of desirable antioxidant compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

Antibacterial activities of wasabi against Escherichia coli O157:H7 and Staphylococcus aureus

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Zhongjing Lu

2016-09-01

Full Text Available Escherichia coli O157:H7 and Staphylococcus aureus are two of the major pathogens frequently involved in foodborne outbreaks. Control of these pathogens in foods is essential to food safety. It is of great interest in the use of natural antimicrobial compounds present in edible plants to control foodborne pathogens as consumers prefer more natural green foods. Allyl isothiocyanate (AITC is an antimicrobial compound naturally present in wasabi (Japanese horseradish and several other edible plants. Although the antibacterial effects of pure AITC and wasabi extract (essential oil against several bacteria have been reported, the antibacterial property of natural wasabi has not been well studied. This study investigated the antibacterial activities of wasabi as well as AITC against E. coli O157:H7 and S. aureus. Chemical analysis showed that AITC is the major isothiocyanate in wasabi. The AITC concentration in the wasabi powder used in this study was 5.91±0.59 mg/g. The minimum inhibitory concentration (MIC of wasabi against E. coli O157:H7 or S. aureus was 1% (or 10 mg/ml. Wasabi at 4% displayed higher bactericidal activity against S. aureus than against E. coli O157:H7. The MIC of AITC against either pathogen was between 10 and 100 µg/ml. AITC at 500 µg/ml was bactericidal against both pathogens while AITC at 1000 µg/ml eliminated E. coli O157:H7 much faster than S. aureus. The results from this study showed that wasabi has strong antibacterial property and has high potential to effectively control E. coli O157:H7 and S. aureus in foods. The antibacterial property along with its natural green color, unique flavor, and advantage to safeguard foods at the point of ingestion makes wasabi a promising natural edible antibacterial plant. The results from this study may be of significant interest to the food industry as they develop new and safe foods. These results may also stimulate more research to evaluate the antibacterial effect of wasabi

Antibacterial Activities of Wasabi against Escherichia coli O157:H7 and Staphylococcus aureus.

Science.gov (United States)

Lu, Zhongjing; Dockery, Christopher R; Crosby, Michael; Chavarria, Katherine; Patterson, Brett; Giedd, Matthew

2016-01-01

Escherichia coli O157:H7 and Staphylococcus aureus are two of the major pathogens frequently involved in foodborne outbreaks. Control of these pathogens in foods is essential to food safety. It is of great interest in the use of natural antimicrobial compounds present in edible plants to control foodborne pathogens as consumers prefer more natural "green" foods. Allyl isothiocyanate (AITC) is an antimicrobial compound naturally present in wasabi (Japanese horseradish) and several other edible plants. Although the antibacterial effects of pure AITC and wasabi extract (essential oil) against several bacteria have been reported, the antibacterial property of natural wasabi has not been well studied. This study investigated the antibacterial activities of wasabi as well as AITC against E . coli O157:H7 and S . aureus . Chemical analysis showed that AITC is the major isothiocyanate in wasabi. The AITC concentration in the wasabi powder used in this study was 5.91 ± 0.59 mg/g. The minimum inhibitory concentration (MIC) of wasabi against E. coli O157:H7 or S. aureus was 1% (or 10 mg/ml). Wasabi at 4% displayed higher bactericidal activity against S. aureus than against E. coli O157:H7. The MIC of AITC against either pathogen was between 10 and 100 μg/ml. AITC at 500 μg/ml was bactericidal against both pathogens while AITC at 1000 μg/ml eliminated E. coli O157:H7 much faster than S. aureus . The results from this study showed that wasabi has strong antibacterial property and has high potential to effectively control E. coli O157:H7 and S. aureus in foods. The antibacterial property along with its natural green color, unique flavor, and advantage to safeguard foods at the point of ingestion makes wasabi a promising natural edible antibacterial plant. The results from this study may be of significant interest to the food industry as they develop new and safe foods. These results may also stimulate more research to evaluate the antibacterial effect of wasabi against other

Three-decade epidemiological analysis of Escherichia coli O15:K52:H1

DEFF Research Database (Denmark)

Olesen, Bente; Scheutz, Flemming; Menard, Megan

2009-01-01

The successful Escherichia coli O15:K52:H1 clonal group provides a case study for the emergence of multiresistant clonal groups of Enterobacteriaceae generally. Accordingly, we tested the hypotheses that, over time, the O15:K52:H1 clonal group has become increasingly (i) virulent and (ii) resistant...... to antibiotics. One hundred archived international E. coli O15:K52:[H1] clinical isolates from 100 unique patients (1975 to 2006) were characterized for diverse phenotypic and molecular traits. All 100 isolates derived from phylogenetic group D and, presumptively, sequence type ST393. They uniformly carried...

Complete Genome Sequences of Two Escherichia coli O145:H28 Outbreak Strains of Food Origin

OpenAIRE

Cooper, Kerry K.; Mandrell, Robert E.; Louie, Jacqueline W.; Korlach, Jonas; Clark, Tyson A.; Parker, Craig T.; Huynh, Steven; Chain, Patrick S. G.; Ahmed, Sanaa; Carter, Michelle Qiu

2014-01-01

Escherichia coli O145:H28 strain RM12581 was isolated from bagged romaine lettuce during a 2010 U.S. lettuce-associated outbreak. E. coli O145:H28 strain RM12761 was isolated from ice cream during a 2007 ice cream-associated outbreak in Belgium. Here we report the complete genome sequences and annotation of both strains.

Growth of Escherichia coli O157:H7, Non-O157 Shiga Toxin-Producing Escherichia coli , and Salmonella in Water and Hydroponic Fertilizer Solutions.

Science.gov (United States)

Shaw, Angela; Helterbran, Kara; Evans, Michael R; Currey, Christopher

2016-12-01

The desire for local, fresh produce year round is driving the growth of hydroponic growing systems in the United States. Many food crops, such as leafy greens and culinary herbs, grown within hydroponics systems have their root systems submerged in recirculating nutrient-dense fertilizer solutions from planting through harvest. If a foodborne pathogen were introduced into this water system, the risk of contamination to the entire crop would be high. Hence, this study was designed to determine whether Escherichia coli O157:H7, non-O157 Shiga toxin-producing E. coli , and Salmonella were able to survive and reproduce in two common hydroponic fertilizer solutions and in water or whether the bacteria would be killed or suppressed by the fertilizer solutions. All the pathogens grew by 1 to 6 log CFU/ml over a 24-h period, depending on the solution. E. coli O157:H7 reached higher levels in the fertilizer solution with plants (3.12 log CFU/ml), whereas non-O157 Shiga toxin-producing E. coli and Salmonella reached higher levels in the fertilizer solution without plants (1.36 to 3.77 log CFU/ml). The foodborne pathogens evaluated here survived for 24 h in the fertilizer solution, and populations grew more rapidly in these solutions than in plain water. Therefore, human pathogens entering the fertilizer solution tanks in hydroponic systems would be expected to rapidly propagate and spread throughout the system and potentially contaminate the entire crop.

Recto-anal junction (RAJ) microbiota composition in Escherichia coli O157:H7 shedding cattle

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Introduction: Cattle are the asymptomatic reservoirs of Escherichia coli O157:H7 (O157) that tend to preferentially colonize the bovine recto-anal junction (RAJ). Therefore, understanding the taxonomic profile, microbial diversity, and microbiota-O157 interactions at the RAJ could give insights into...

Transcriptome Changes of Escherichia coli, Enterococcus faecalis, and Escherichia coli O157:H7 Laboratory Strains in Response to Photo-Degraded DOM

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Adelumola Oladeinde

2018-05-01

Full Text Available In this study, we investigated gene expression changes in three bacterial strains (Escherichia coli C3000, Escherichia coli O157:H7 B6914, and Enterococcus faecalis ATCC 29212, commonly used as indicators of water quality and as control strains in clinical, food, and water microbiology laboratories. Bacterial transcriptome responses from pure cultures were monitored in microcosms containing water amended with manure-derived dissolved organic matter (DOM, previously exposed to simulated sunlight for 12 h. We used RNA sequencing (RNA-seq and quantitative real-time reverse transcriptase (qRT-PCR to compare differentially expressed temporal transcripts between bacteria incubated in microcosms containing sunlight irradiated and non-irradiated DOM, for up to 24 h. In addition, we used whole genome sequencing simultaneously with RNA-seq to identify single nucleotide variants (SNV acquired in bacterial populations during incubation. These results indicate that E. coli and E. faecalis have different mechanisms for removal of reactive oxygen species (ROS produced from irradiated DOM. They are also able to produce micromolar concentrations of H2O2 from non-irradiated DOM, that should be detrimental to other bacteria present in the environment. Notably, this study provides an assessment of the role of two conjugative plasmids carried by the E. faecalis and highlights the differences in the overall survival dynamics of environmentally-relevant bacteria in the presence of naturally-produced ROS.

Enterohemorrhagic Escherichia coli Hybrid Pathotype O80:H2 as a New Therapeutic Challenge

Science.gov (United States)

Soysal, Nurcan; Mariani-Kurkdjian, Patricia; Smail, Yasmine; Liguori, Sandrine; Gouali, Malika; Loukiadis, Estelle; Fach, Patrick; Bruyand, Mathias; Blanco, Jorge; Bidet, Philippe

2016-01-01

We describe the epidemiology, clinical features, and molecular characterization of enterohemorrhagic Escherichia coli (EHEC) infections caused by the singular hybrid pathotype O80:H2, and we examine the influence of antibiotics on Shiga toxin production. In France, during 2005–2014, a total of 54 patients were infected with EHEC O80:H2; 91% had hemolytic uremic syndrome. Two patients had invasive infections, and 2 died. All strains carried stx2 (variants stx2a, 2c, or 2d); the rare intimin gene (eae-ξ); and at least 4 genes characteristic of pS88, a plasmid associated with extraintestinal virulence. Similar strains were found in Spain. All isolates belonged to the same clonal group. At subinhibitory concentrations, azithromycin decreased Shiga toxin production significantly, ciprofloxacin increased it substantially, and ceftriaxone had no major effect. Antibiotic combinations that included azithromycin also were tested. EHEC O80:H2, which can induce hemolytic uremic syndrome complicated by bacteremia, is emerging in France. However, azithromycin might effectively combat these infections. PMID:27533474

Occurrence of Coliform and Escherichia coli Contamination and Absence of Escherichia coli O157:H7 on Romaine Lettuce from Retail Stores in the Upper Midwest.

Science.gov (United States)

Greve, Josephine D; Zietlow, Mark S; Miller, Kevin M; Ellingson, Jay L E

2015-09-01

A total of 720 whole, romaine lettuce heads were purchased from retail locations in the Upper Midwest and assessed for coliform and Escherichia coli contamination and for the presence of E. coli O157:H7. During a 16-month period (August 2010 through December 2011), coliform and E. coli counts were enumerated on Petrifilm, and the presence of E. coli O157:H7 and the virulence gene eae was evaluated by real-time PCR (qPCR). Over half (400 of 720) of the lettuce samples were processed with an immunomagnetic separation step before the qPCR assay. All retail lettuce samples were negative for E. coli O157:H7 when tested with the R.A.P.I.D. LT qPCR targeting a region of the O-antigen, and only two (0.28%) were positive for the eae gene when tested with LightCycler qPCR. On Petrifilm, coliform counts of most lettuce samples (96.4%) were between lettuce samples (98.2%) were lettuce heads. These results contribute to the limited recorded data and understanding of microbial contamination of whole romaine lettuce heads purchased from retail locations, specifically revealing the absence of E. coli O157:H7 and low levels of contamination with coliforms and other E. coli strains.

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...

Fermentation of sweet whey by recombinant Escherichia coli K011 Fermentação de soro de leite por Escherichia coli KO11 recombinante

Directory of Open Access Journals (Sweden)

Amarildo Ricardo Leite

2000-09-01

Full Text Available The production of ethanol from sweet whey using the recombinant Escherichia coli KO11, in batch fermentation, was tested. The maximum ethanol yield was reached after 96h, representing only 38% of the theoretical yield. The supplementation of whey with components of LB broth increased the maximum yield to 96% in 72h. The addition of 0.5% yeast extract to whey resulted in maximum yield of 74% at 36h and it increased to over 100% when yeast extract and trace metals solution (Fe++, Mn++ and Zn++ were added.A produção de etanol a partir de soro de leite empregando a cepa Escherichia coli KO11 recombinante, em fermentação de batelada, foi testada. O rendimento máximo de etanol foi obtido em 96h, representando apenas 38% do rendimento teórico. A suplementação do soro com os componentes do caldo LB aumentou o rendimento para 96% em 72h. A adição de 0,5% de extrato de levedura ao soro resultou em um rendimento máximo de 74% em 36h que aumentou para acima de 100% quando se adicionou extrato de levedura e uma solução de metais traço (Fe++, Mn++ e Zn++.

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...

Patotipos de Escherichia coli causadores de diarreia em bezerros: uma atualização

Directory of Open Access Journals (Sweden)

Fernanda M. Coura

2014-09-01

Full Text Available A diarreia é uma das doenças mais frequentes de bezerros com até 30 dias de idade e é uma importante causa de perdas econômicas. Sua etiologia é complexa e envolve a interação de diversos fatores infecciosos, nutricionais, imunológicos, gerenciais e ambientais. Os principais sinais clínicos são a diarreia, desidratação progressiva, acidose metabólica, desequilíbrio de eletrólitos e balanço energético negativo com ou sem hipoglicemia, que se não tratados, levam à morte do animal. Escherichia coli se destaca como um importante enteropatógeno envolvido na síndrome diarreica. Cepas de E. coli patogênicas são classificadas em grupos ou patotipos, de acordo com a produção de fatores de virulência e mecanismos pelos quais causam doença. Já foram identificados cinco patotipos de E. coli associados à diarreia em bezerros: E. coli enterotoxigênica (ETEC, E. coli enteropatogênica (EPEC, E. coli enterohemorrágica (EHEC, E. coli produtora de toxina Shiga (STEC e E. coli necrotoxigênica (NTEC. Nesse artigo apresentamos as principais características e os atuais conhecimentos sobre os patotipos de E. coli causadores de diarreia em bezerros.

Inhibition of Escherichia coli O157:H7 on stainless steel using Pseudomonas veronii biofilms.

Science.gov (United States)

Kim, Y; Kim, H; Beuchat, L R; Ryu, J-H

2018-05-01

We produced a Pseudomonas veronii biofilm on the surface of a stainless steel that is inhibitory to Escherichia coli O157:H7. Pseudomonas veronii strain KACC 81051BP, isolated from lettuce, readily formed biofilm on the surface of stainless steel coupons (SSCs) immersed in tryptic soy broth at 25°C. Cells showed significantly (P ≤ 0·05) enhanced tolerance to desiccation stress (43% relative humidity (RH)) and retained antimicrobial activity against E. coli O157:H7. The number of E. coli O157:H7 (control; 4·1 ± 0·1 log CFU per coupon) on sterile SSCs decreased to 2·7 ± 0·2 log CFU per coupon after exposure to 43% RH at 25°C for 48 h, while the population of E. coli O157:H7 (4·1 ± 0·0 log CFU per coupon) on SSCs containing P. veronii biofilm decreased to below the theoretical detection limit (1·5 log CFU per coupon) within 24 h. The antimicrobial biofilm produced on stainless steel may have application in preventing cross-contamination by E. coli O157:H7 on other abiotic surfaces in food-contact environments. The presence of Escherichia coli O157:H7 on environmental surfaces of food manufacturing, transportation and storage facilities is a significant food safety concern because it can result in cross-contamination of food products. In this study, we developed a Pseudomonas veronii biofilm on the surface of a stainless steel that inhibits the growth of E. coli O157:H7. Since P. veronii in biofilm resists desiccation, it provides persistent antimicrobial activity. Information presented here provides novel and practical insights to developing biological strategies to inactivate E. coli O157:H7 on diverse surfaces in food processing and handling environments. © 2018 The Society for Applied Microbiology.

Persistence of Escherichia coli O157:H7 in dairy fermentation systems.

Science.gov (United States)

Dineen, S S; Takeuchi, K; Soudah, J E; Boor, K J

1998-12-01

We examined (i) the persistence of Escherichia coli O157:H7 as a postpasteurization contaminant in fermented dairy products; (ii) the ability of E. coli O157:H7 strains with and without the general stress regulatory protein, RpoS, to compete with commercial starter cultures in fermentation systems; and (iii) the survival of E. coli O157:H7 in the yogurt production process. In commercial products inoculated with 10(3) CFU/ml, E. coli O157:H7 was recovered for up to 12 days in yogurt (pH 4.0), 28 days in sour cream (pH 4.3), and at levels > 10(2) CFU/ml at 35 days in buttermilk (pH 4.1). For the starter culture competition trials, the relative inhibition of E. coli O157:H7 in the experimental fermentation systems was, in decreasing order, thermophilic culture mixture, Lactobacillus delbrueckii subsp. bulgaricus R110 alone, Lactococcus lactis subsp. lactis D280 alone, Lactococcus lactis subsp. cremoris D62 alone, and Streptococcus thermophilus C90 alone showing the least inhibition. Recovery of the rpoS mutant was lower than recovery of its wild-type parent by 72 h or earlier in the presence of individual starter cultures. No E. coli O157:H7 were recovered after the curd formation step in yogurt manufactured with milk inoculated with 10(5) CFU/ml. Our results show that (i) postprocessing entry of E. coli O157:H7 into fermented dairy products represents a potential health hazard; (ii) commercial starter cultures differ in their ability to reduce E. coli O157:H7 CFU numbers in fermentation systems; and (iii) the RpoS protein appears to most effectively contribute to bacterial survival in the presence of conditions that are moderately lethal to the cell.

Persistence of Escherichia coli O157:H7 and total Escherichia coli in feces and feedlot surface manure from cattle fed diets with or without corn or sorghum wet distillers grains with solubles

Science.gov (United States)

Feeding corn wet distillers grains with solubles (WDGS) to cattle can increase the load of Escherichia coli O157:H7 in feces and on hides, but the mechanisms are not fully understood. The objective of these experiments was to examine a role for the persistence of E. coli O157:H7 in the feces and fee...

Classification of non-O157 shiga toxin-producing escherichia coli(STEC) serotypes with hyperspectral microscope imaging

Science.gov (United States)

Non-O157 Shiga toxin-producing Escherichia coli (STEC) strains such as O26, O45, O103, O111, O121 and O145 are recognized as serious outbreak to cause human illness due to their toxicity. A conventional microbiological method for cell counting is laborious and needs long time for the results. Since ...

Carvacrol and p-cymene inactivate Escherichia coli O157:H7 in apple juice

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Roller Sibel

2005-06-01

Full Text Available Abstract Background Outbreaks of food poisoning associated with drinking un-pasteurised apple juice contaminated with enterohaemorrhagic Escherichia coli O157:H7 are a cause of serious illness and occasionally death. Whilst a well-established heat process (pasteurisation will readily eliminate the pathogen, some consumers are demanding more fresh-like foods that have not been subjected to processing methods that are perceived as severe and may lead to loss of flavour and vitamins. Therefore, alternative methods are being investigated to replace pasteurisation and improve the safety of minimally-processed juices. The addition of natural antimicrobial substances such as the phenolic substances carvacrol and p-cymene (derived from the essential oils of herbs and spices provides a potential new route to assure safety and extend the shelf-life of raw fruit juices. The aim of this study was to evaluate the addition of very low concentrations (0.25–1.25 mM of carvacrol and p-cymene both individually and in combination as a novel means of controlling Escherichia coli O157:H7 in un-pasteurised apple juice. Results When inoculated at a level of 4 log CFU/ml into un-pasteurised apple juice (pH 3.20 ± 0.06, Escherichia coli O157:H7 survived for up to 3 and 19 days at 25° and 4°C, respectively. Treatment of the juice with 1.25 mM carvacrol or p-cymene reduced the numbers of E. coli O157:H7 to undetectable levels within 1–2 days at both storage temperatures. The effective concentrations of carvacrol could be reduced even further by combining it at 0.5 mM with cymene at 0.25 mM. The phenolic compounds were biocidal against both spoilage yeasts and E. coli O157:H7 thereby increasing the shelf-life and improving the safety of un-pasteurised apple juice, particularly when stored at chill temperatures. Conclusion The results showed that the natural antimicrobial compounds carvacrol and p-cymene could potentially be used to extend the shelf life and improve

Effect of carvacrol on O157 and non-O157 Shiga toxin producing Escherichia coli

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Alexandros Stratakos

2017-06-01

Full Text Available Shiga toxin Escherichia coli (STEC strains are important foodborne bacteria linked to diarrhea, enteritis, hemolytic-uremic syndrome and in some cases death. E. coli O157:H7 is the most common strain amongst STECs however non-O157 STECs have been connected with several outbreaks on an international level.  The use of natural plant extracts to reduce the risk from foodborne pathogens is gaining increasing importance. Therefore in this study, we tested the antibacterial effect of carvacrol, a major component of oregano essential oil, on E. coli serogroups O157, O26, O45, O103, O111, O121, O145 as well as serogroup O104 responsible for the massive outbreak in Germany in 2011. Carvacrol showed antibacterial effect on all strains tested. The relative electric conductivity was assessed in order to investigate the changes in membrane permeability and thus to investigate the antimicrobial mechanism of carvacrol. Results showed that the relative conductivity increased with increasing concentrations of carvacrol which showed that there was an increasing leakage of electrolytes due to disruption of the cell membrane. The data presented here revealed that carvacrol has the potential to be used as a natural antimicrobial against STECs.

Detecção de fatores de virulência de Escherichia coli e análise de Salmonella spp. em psitacídeos Detection of virulence factors in Escherichia coli and analysis of Salmonella spp. in psittacines

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Isadora M. de O. Corrêa

2013-02-01

Full Text Available A flora entérica dos psitacídeos é composta principalmente por bactérias Gram positivas. Bactérias Gram negativas, como Escherichia coli e Salmonella spp., apresentam elevado potencial patogênico, sendo consideradas indicativo de problemas de manejo, que poderão culminar em manifestação de doenças em decorrência de fatores estressantes, dietas deficientes e superlotação, combinados com alta carga bacteriana no ambiente. O objetivo deste trabalho foi avaliar a presença de Salmonella spp., Escherichia coli e os fatores de virulência dos genes iss e iutA dos isolados de E. coli. Analisou-se um total de 44 amostras provenientes de psitacídeos criados em cativeiro, sendo estas 15 fragmentos de órgãos de aves submetidas a exame de necropsia e também 29 amostras de swabs de cloaca e inglúvio de papagaios-charão (Amazona pretrei criados em cativeiro. Nenhuma amostra foi positiva para Salmonella spp. Nas amostras de E. coli detectou-se ambos os fatores de virulência pesquisados.The enteric flora of psittacines is mainly composed of Gram positive bacteria. Gram negative bacteria, like Escherichia coli and Salmonella spp., have a high pathogenic potential and can be considerate as an indicative of management problems that may culminate in disease manifestation due to stress factors, poor diets and overcrowding, in combination with a high bacterial load on the environment. The objective of this study was evaluated the presence of Salmonella spp., Escherichia coli and the virulence genes iss and iutA from E. coli isolates. Forty-four samples were analyzed from psittacines living in captivity, which fifteen samples were from organs fragments of necropsied birds, and twenty-nine were from cloacal and crop swabs of red-spectacled parrots (Amazona pretrei keeping in captivity. No samples were positive for Salmonella spp. In the samples in which E. coli was detected, both virulence factors (genes iss and iutA were present.

Irradiation effect of escherichia coli O157 : H7 in meats

International Nuclear Information System (INIS)

Ito, Hitoshi; Harsojo

1998-01-01

Escherichia coli O157 : H7 is a rapidly emerging food-born pathogen which has been linked to outbreaks of hemorrhagic diarrhea in Japan, USA or many European countries. From this study, two strains of E. coli O157 : H7 were isolated from beef and chicken meats in each one sample of 4 replicates. Some of the biochemical characteristics of these isolates were different from type strain IID959. These isolates could grow quickly at 10degC on cultivation of nutrient agar. D 10 value of these isolates were obtained to be 0.06kGy in 0.067M phosphate buffer suspension which were highly sensitive than D 10 value of 0.12kGy on type strain IID959. On the irradiation effect of type strain IID959 in ground beef, D 10 value was obtained as 0.26kGy at fresh condition and 0.46kGy at frozen condition, respectively. From these results, necessary dose for elimination of E. coli O157 : H7 was decided as 1.5kGy for fresh meats and 3kGy for frozen meats. (author)

Antibacterial effect of lactoferricin B on Escherichia coli O157:H7 in ground beef.

Science.gov (United States)

Venkitanarayanan, K S; Zhao, T; Doyle, M P

1999-07-01

The antibacterial activity of lactoferricin B on enterohemorrhagic Escherichia coli O157:H7 in 1% peptone medium and ground beef was studied at 4 and 10 degrees C. In 1% peptone medium, 50 and 100 microg of lactoferricin B per ml reduced E. coli O157:H7 populations by approximately 0.7 and 2.0 log CFU/ml, respectively. Studies comparing the antibacterial effect of lactoferricin B on E. coli O157:H7 in 1% peptone at pH 5.5 and 7.2 did not reveal any significant difference (P > 0.5) at the two pH values. Lactoferricin B (100 microg/g) reduced E. coli O157:H7 population in ground beef by about 0.8 log CFU/g (P 0.5) was observed in the total plate count between treatment and control ground beef samples stored at 4 and 10 degrees C. The antibacterial effect of lactoferricin B on E. coli O157:H7 observed in this study is not of sufficient magnitude to merit its use in ground beef for controlling the pathogen.

Aislamiento, caracterización y subtipificación de cepas de Escherichia coli O157:H7 a partir de productos cárnicos y leche Isolation, characterization and typing of Escherichia coli O157:H7 strains from beef products and milk

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M. L. Roldán

2007-06-01

Full Text Available Escherichia coli productor de toxina Shiga (Stx (STEC O157:H7 es un patógeno asociado a enfermedades transmitidas por alimentos, fundamentalmente de origen animal. Se investigó la presencia de E. coli O157 en 250 muestras de carne picada y hamburguesas obtenidas de comercios de las ciudades de Santa Fe y Santo Tomé (Pcia. de Santa Fe y en 150 muestras de leche provenientes de tanques de enfriado de tambos de la región, utilizando enriquecimiento selectivo y separación inmunomagnética. A partir de 3 muestras de carne (1,2% se aislaron cepas E. coli O157:H7 stx2, eae, y ehxA positivas, que pudieron ser diferenciadas mediante electroforesis de campo pulsado, fagotipificación y genotipificación de stx. No se aislaron cepas STEC O157:H7 a partir de las muestras de leche. Estos hallazgos confirman la participación de los alimentos de origen animal en la epidemiología de las enfermedades producidas por E. coli O157:H7.Shiga toxin (Stx-producing Escherichia coli (STEC is an emergent pathogen associated with foodborne diseases, especially foodstuffs of animal origin. A total of 250 beef samples (ground beef and hamburgers obtained from retail outlets in Santa Fe and Santo Tomé cities, and 150 milk samples from bulk tank milk from dairy barns of the region were analyzed by selective enrichment and immunomagnetic separation. Escherichia coli O157:H7 stx2, eae and ehxA positive strains were isolated from three (1.2% beef samples. The strains could be differentiated by pulsed-field gel electrophoresis, phagetyping and genotyping of stx. The milk samples were negative for STEC O157. These findings confirm the role of food of animal origin in the epidemiology of E. coli O157:H7 - associated diseases.

Detección de Escherichia coli O157: H7 en carne picada fresca y hamburguesas congeladas Escherichia coli O157: H7 detection in fresh ground beef and hamburgers

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M. A. Marzocca

2006-03-01

Full Text Available Escherichia coli O157:H7 es un patógeno emergente asociado a enfermedades transmitidas por alimentos. En el año 1982 fue reconocido por primera vez, en los Estados Unidos, como causante de dos brotes de colitis hemorrágica. Hoy se sabe que la mayoría de los casos de síndrome urémico hemolítico son ocasionados por este microorganismo. El objetivo del trabajo fue detectar su presencia en carne picada fresca y hamburguesas congeladas, muestras obtenidas en puntos de venta de nuestra cadena de supermercados en un total de 37 y 43, respectivamente, en el período comprendido entre abril de 2003 y agosto de 2004. Las mismas fueron procesadas utilizando el caldo selectivo para enriquecimiento EC modificado conteniendo novobiocina, seguido de la aplicación de un método de inmunocaptura (TECRA E. COLI O157 IMMUNOCAPTURE TM ECOICM 20, y posterior aislamiento en agar MacConkey sorbitol suplementado con cefixima y telurito de potasio y un medio cromogénico. Las cepas sospechosas fueron caracterizadas a genotípicamente mediante la detección de los genes de virulencia stx1, stx2, eaeA y EHEC-hlyA por PCR e hibridación con sondas genéticas, b fenotípicamente mediante la determinación del serotipo, sensibilidad a los antimicrobianos por el método de difusión de Kirby-Bauer y producción de Stx por ensayo de citotoxicidad específica en células Vero. Se aisló E. coli O157:H7 en una sola muestra de carne picada fresca (2,7% caracterizada como gen eae (+/stx2/EHEC-hlyA.Escherichia coli O157:H7 is an emergent pathogen associated with food transmitted diseases. In 1982, Escherichia coli 0157:H7 was for the first time identified as the cause of two hemorrhagic colitis outbreaks in the United States. It is now well known that most cases of hemolytic uremic syndrome are caused by these bacteria. The objective of this work was to detect the microorganism in fresh ground beef and hamburgers. From April 2003 to August 2004 samples were taken at sale

The occurrence of Escherichia coli O157:H7 in market and abattoir ...

African Journals Online (AJOL)

Escherichia coli O157:H7 is a newly emerging pathogen frequently associated with the consumption of foods of bovine origin. The severity of the infections caused by this food borne pathogen in the young and the elderly has had a tremendous impact on human health and food industry. The present study evaluated the ...

prevalence of escherichia coli 0157:h7 in fresh and roasted beef

African Journals Online (AJOL)

DR. AMINU

The prevalence of Enterohemorrhagic Escherichia coli 0157:H7 in 300 fresh beef and 150 roasted beef samples from ... likely cause of E. coli O157:H7 infection is undercooked ground beef. ..... coli O157:H7 in a sheep model. Appl. Environ.

Genetic Transfer of Salmonella typhimurium and Escherichia coli Lipopolysaccharide Antigens to Escherichia coli K-12

Science.gov (United States)

Jones, Randall T.; Koeltzow, Donald E.; Stocker, B. A. D.

1972-01-01

Escherichia coli K-12 ϰ971 was crossed with a smooth Salmonella typhimurium donor, HfrK6, which transfers early the ilv-linked rfa region determining lipopolysaccharide (LPS) core structure. Two ilv+ hybrids differing in their response to the LPS-specific phages FO and C21 were then crossed with S. typhimurium HfrK9, which transfers early the rfb gene cluster determining O repeat unit structure. Most recombinants selected for his+ (near rfb) were agglutinated by Salmonella factor 4 antiserum. Transfer of an F′ factor (FS400) carrying the rfb–his region of S. typhimurium to the same two ilv+ hybrids gave similar results. LPS extracted from two ilv+,his+, factor 4-positive hybrids contained abequose, the immunodominant sugar for factor 4 specificity. By contrast, his+ hybrids obtained from ϰ971 itself by similar HfrK9 and F′FS400 crosses were not agglutinated by factor 4 antiserum, indicating that the parental E. coli ϰ971 does not have the capacity to attach Salmonella O repeat units to its LPS core. It is concluded that the Salmonella rfb genes are expressed only in E. coli ϰ971 hybrids which have also acquired ilv-linked genes (presumably rfa genes affecting core structure or O-translocase ability, or both) from a S. typhimurium donor. When E. coli ϰ971 was crossed with a smooth E. coli donor, Hfr59, of serotype O8, which transfers his early, most his+ recombinants were agglutinated by E. coli O8 antiserum and lysed by the O8-specific phage, Ω8. This suggests that, although the parental E. coli K-12 strain ϰ971 cannot attach Salmonella-specific repeat units to its LPS core, it does have the capacity to attach E. coli O8-specific repeat units. PMID:4559827

Mathematical modeling of growth of non-O157 Shiga Toxin-producing Escherichia coli in raw ground beef

Science.gov (United States)

The objective of this study was to investigate the growth of Shiga toxin-producing Escherichia coli (STEC, including serogroups O45, O103, O111, O121, and O145) in raw ground beef and to develop mathematical models to describe the bacterial growth under different temperature conditions. Three prima...

Structure and gene cluster of the O-antigen of Escherichia coli O54.

Science.gov (United States)

Naumenko, Olesya I; Guo, Xi; Senchenkova, Sof'ya N; Geng, Peng; Perepelov, Andrei V; Shashkov, Alexander S; Liu, Bin; Knirel, Yuriy A

2018-06-15

Mild acid hydrolysis of the lipopolysaccharide of Escherichia coli O54 afforded an O-polysaccharide, which was studied by sugar analysis, solvolysis with anhydrous trifluoroacetic acid, and 1 H and 13 C NMR spectroscopy. Solvolysis cleaved predominantly the linkage of β-d-Ribf and, to a lesser extent, that of β-d-GlcpNAc, whereas the other linkages, including the linkage of α-l-Rhap, were stable under selected conditions (40 °C, 5 h). The following structure of the O-polysaccharide was established: →4)-α-d-GalpA-(1 → 2)-α-l-Rhap-(1 → 2)-β-d-Ribf-(1 → 4)-β-d-Galp-(1 → 3)-β-d-GlcpNAc-(1→ The O-antigen gene cluster of E. coli O54 was analyzed and found to be consistent in general with the O-polysaccharide structure established but there were two exceptions: i) in the cluster, there were genes for phosphoserine phosphatase and serine transferase, which have no apparent role in the O-polysaccharide synthesis, and ii) no ribofuranosyltransferase gene was present in the cluster. Both uncommon features are shared by some other enteric bacteria. Copyright © 2018 Elsevier Ltd. All rights reserved.

Uso do açafrão (Curcuma longa L. na redução da Escherichia coli (ATCC 25922 e Enterobacter aerogenes (ATCC 13048 em ricota The use of turmeric in the reduction of Escherichia coli (ATCC 25922 and Enterobacter aerogenes (ATCC 13048 in ricotta

Directory of Open Access Journals (Sweden)

Sandra Ribeiro Maia

2004-04-01

Full Text Available Considerando o envolvimento de queijos como veículo de microrganismos patogênicos, foi avaliada a eficiência do extrato alcoólico de cúrcuma adicionado à ricota, na redução de Escherichia coli e Enterobacter aerogenes. Foram fabricados três lotes de ricota cremosa e inoculados com 104 UFC/mL de Escherichia coli (ATCC 25922 e 105 UFC/mL de Enterobacter aerogenes (ATCC 13048. Às ricotas, foram adicionados 0,4% de NaCl e extrato alcoólico de Curcuma longa L., em concentrações que variaram de 0,0% a 2,0%. As ricotas foram avaliadas físico-química e microbiologicamente em 0, 1, 7, 14 e 21 dias de armazenamento refrigerado. O percentual de umidade das ricotas foi, em média, de 73%. O pH médio observado foi de 5,4 e o percentual de gordura de 3%. Pelos resultados, evidenciou-se, após 21 dias, uma redução do número de Escherichia coli de aproximadamente dois ciclos logaritmicos nos tratamentos utilizados de 0,5%, 1,0%, 1,5% e 2,0% de cúrcuma. Já para Enterobacter aerogenes, a redução foi menor, de aproximadamente um ciclo logaritmico, de 105 UFC/mL para 104 UFC/mL, também nos tratamentos utilizados de 0,5%, 1,0%, 1,5% e 2,0% de cúrcuma. Apesar de os resultados evidenciarem uma redução do número de células viáveis dos microrganismos avaliados, a cúrcuma não deverá ser o único meio preservativo, considerando uma contaminação inicial de 104 UFC/mL de Escherichia coli e 105 UFC/mL de Enterobacter aerogenes, pois não atenderia à legislação vigente quanto aos requisitos microbiológicos para queijos.Considering the cheese involvement as a vehicle of pathogenic microorganisms it was evaluated the eficciency of the ethanolic turmeric extract added to ricotta, in the reduction of Escherichia coli and Enterobacter aerogenes. Three lots of creamy ricotta were manufacturated and inoculated with 104 UFC/mL of Escherichia coli (ATCC 25922 and 105 UFC/mL of Enterobacter aerogenes (ATCC 13048. It was added 0,4% of NaCl and

Detection and characterization of Escherichia coli O157:H7 from feral pigeon in Qom province, Iran

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Hossein Esameili

2015-02-01

Full Text Available Objective: To detect and characterize Escherichia coli (E. coli O157:H7 in feral pigeons in Qom province, Iran. Methods: In this survey, 290 cloacal samples were obtained from trapped feral pigeons in Qom province. Microbiological, biochemical and serological examinations were done to detect the E. coli O157:H7. Isolates were subjected to multiplex polymerase chain reaction for the detection of stx1, stx2, eaeA and hlyA genes. Results: Four samples (1.38% were positive for E. coli O157:H7 by using O157 and H7 antisera and only one E. coli O157:H7 strain isolated showed the presence of stx1, stx2, eaeA and hlyA genes. Conclusions: The results of present survey revealed that feral pigeons in Qom province had the potential to be a reservoir of E. coli O157:H7. The low prevalence of E. coli O157:H7 can be attributed to sampling each pigeon just once and fecal culture limits, and true prevalence of the E. coli O157:H7 might be higher than our findings.

Evaluation of immunomagnetic separation and PCR for the detection of Escherichia coli O157 in animal feces and meats

NARCIS (Netherlands)

Islam, M.A.; Heuvelink, A.E.; Talukder, K.A.; Zwietering, M.H.; Boer, de E.

2006-01-01

Series of animal feces and meat samples artificially contaminated with strains of Escherichia coli O157 isolated from different sources were tested by both an immunomagnetic separation (IMS)-based method and a PCR method using primers specific for a portion of the rfbE gene of E. coli O157. IMS is

The genome and proteome of a virulent Escherichia coli O157:H7 bacteriophage closely resembling Salmonella phage Felix O1

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Waddell Thomas E

2009-04-01

Full Text Available Abstract Based upon whole genome and proteome analysis, Escherichia coli O157:H7-specific bacteriophage (phage wV8 belongs to the new myoviral genus, "the Felix O1-like viruses" along with Salmonella phage Felix O1 and Erwinia amylovora phage φEa21-4. The genome characteristics of phage wV8 (size 88.49 kb, mol%G+C 38.9, 138 ORFs, 23 tRNAs are very similar to those of phage Felix O1 (86.16 kb, 39.0 mol%G+C, 131 ORFs and 22 tRNAs and, indeed most of the proteins have their closest homologs within Felix O1. Approximately one-half of the Escherichia coli O157:H7 mutants resistant to phage wV8 still serotype as O157:H7 indicating that this phage may recognize, like coliphage T4, two different surface receptors: lipopolysaccharide and, perhaps, an outer membrane protein.

Most probable number methodology for quantifying dilute concentrations and fluxes of Escherichia coli O157:H7 in surface waters.

Science.gov (United States)

Jenkins, M B; Endale, D M; Fisher, D S; Gay, P A

2009-02-01

To better understand the transport and enumeration of dilute densities of Escherichia coli O157:H7 in agricultural watersheds, we developed a culture-based, five tube-multiple dilution most probable number (MPN) method. The MPN method combined a filtration technique for large volumes of surface water with standard selective media, biochemical and immunological tests, and a TaqMan confirmation step. This method determined E. coli O157:H7 concentrations as low as 0.1 MPN per litre, with a 95% confidence level of 0.01-0.7 MPN per litre. Escherichia coli O157:H7 densities ranged from not detectable to 9 MPN per litre for pond inflow, from not detectable to 0.9 MPN per litre for pond outflow and from not detectable to 8.3 MPN per litre for within pond. The MPN methodology was extended to mass flux determinations. Fluxes of E. coli O157:H7 ranged from 10(4) MPN per hour. This culture-based method can detect small numbers of viable/culturable E. coli O157:H7 in surface waters of watersheds containing animal agriculture and wildlife. This MPN method will improve our understanding of the transport and fate of E. coli O157:H7 in agricultural watersheds, and can be the basis of collections of environmental E. coli O157:H7.

Optimized enrichment for the detection of Escherichia coli O26 in French raw milk cheeses.

Science.gov (United States)

Savoye, F; Rozand, C; Bouvier, M; Gleizal, A; Thevenot, D

2011-06-01

Our main objective was to optimize the enrichment of Escherichia coli O26 in raw milk cheeses for their subsequent detection with a new automated immunological method. Ten enrichment broths were tested for the detection of E. coli O26. Two categories of experimentally inoculated raw milk cheeses, semi-hard uncooked cheese and 'Camembert' type cheese, were initially used to investigate the relative efficacy of the different enrichments. The enrichments that were considered optimal for the growth of E. coli O26 in these cheeses were then challenged with other types of raw milk cheeses. Buffered peptone water supplemented with cefixim-tellurite and acriflavin was shown to optimize the growth of E. coli O26 artificially inoculated in the cheeses tested. Despite the low inoculum level (1-10 CFU per 25 g) in the cheeses, E. coli O26 counts reached at least 5.10(4) CFU ml(-1) after 24-h incubation at 41.5 °C in this medium. All the experimentally inoculated cheeses were found positive by the immunological method in the enrichment broth selected. Optimized E. coli O26 enrichment and rapid detection constitute the first steps of a complete procedure that could be used in routine to detect E. coli O26 in raw milk cheeses. © 2011 The Authors. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.

Utilization of evolutionary model, bioinformatics and heuristics for development of a multiplex Escherichia coli O157:H7 PCR assay

Science.gov (United States)

Introduction: Escherichia coli O157:H7 is a devastating foodborne pathogen causing many foodborne outbreaks worldwide with significant morbidity and mortality. The plasticity of the E. coli O157:H7 genome, inconsistent expression of surface antigens, and sharing of genetic elements with other non-...

Earthworms as vectors of Escherichia coli O157:H7 in soil and vermicomposts.

Science.gov (United States)

Williams, A Prysor; Roberts, Paula; Avery, Lisa M; Killham, Ken; Jones, David L

2006-10-01

Survival and movement of Escherichia coli O157:H7 in both soil and vermicompost is of concern with regards to human health. Whilst it is accepted that E. coli O157:H7 can persist for considerable periods in soils, it is not expected to survive thermophilic composting processes. However, the natural behavior of earthworms is increasingly utilized for composting (vermicomposting), and the extent to which earthworms promote the survival and dispersal of the bacterium within such systems is unknown. The faecal material produced by earthworms provides a ready supply of labile organic substrates to surrounding microbes within soil and compost, thus promoting microbial activity. Earthworms can also cause significant movement of organisms through the channels they form. Survival and dispersal of E. coli O157:H7 were monitored in contaminated soil and farmyard manure subjected to earthworm digestion over 21 days. Our findings lead to the conclusion that anecic earthworms such as Lumbricus terrestris may significantly aid vertical movement of E. coli O157 in soil, whereas epigeic earthworms such as Dendrobaena veneta significantly aid lateral movement within compost. Although the presence of earthworms in soil and compost may aid proliferation of E. coli O157 in early stages of contamination, long-term persistence of the pathogen appears to be unaffected.

Enteroaggregative, Shiga Toxin-Producing Escherichia coli O111:H2 Associated with an Outbreak of Hemolytic-Uremic Syndrome

Science.gov (United States)

Morabito, Stefano; Karch, Helge; Mariani-Kurkdjian, Patrizia; Schmidt, Herbert; Minelli, Fabio; Bingen, Edouard; Caprioli, Alfredo

1998-01-01

Shiga toxin-producing Escherichia coli O111:H2 strains from an outbreak of hemolytic-uremic syndrome showed aggregative adhesion to HEp-2 cells and harbored large plasmids which hybridized with the enteroaggregative E. coli probe PCVD432. These strains present a novel combination of virulence factors and might be as pathogenic to humans as the classic enterohemorrhagic E. coli. PMID:9508328

Complete Genome Sequence of Enteroinvasive Escherichia coli O96:H19 Associated with a Severe Foodborne Outbreak

Science.gov (United States)

Pettengill, Emily A.; Hoffmann, Maria; Roberts, Richard J.; Payne, Justin; Allard, Marc; Michelacci, Valeria; Minelli, Fabio; Morabito, Stefano

2015-01-01

We present here the complete genome sequence of a strain of enteroinvasive Escherichia coli O96:H19 from a severe foodborne outbreak in a canteen in Italy in 2014. The complete genome may provide important information about the acquired pathogenicity of this strain and the transition between commensal and pathogenic E. coli. PMID:26251502

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...

Elimination of Escherichia coli O157:H7 in meats by gamma irradiation

International Nuclear Information System (INIS)

Thayer, D.W.; Boyd, G.

1993-01-01

Undercooked and raw meat has been linked to outbreaks of hemorrhagic diarrhea due to the presence of Escherichia coli O157:H7; therefore, treatment with ionizing radiation was investigated as a potential method for the elimination of this organism. Response-surface methods were used to study the effects of irradiation dose (0 to 2.0 kGy), temperature (-20 to +20 degrees C), and atmosphere (air and vacuum) on E. coli O157:H7 in mechanically deboned chicken meat. Differences in irradiation dose and temperature significantly affected the results. Ninety percent of the viable E. coli in chicken meat was eliminated by doses of 0.27 kGy at +5 degrees C and 0.42 kGy at -5 degrees C. Small, but significant, differences in radiation resistance by E. coli were found when finely ground lean beef rather than chicken was the substrate. Unlike nonirradiated samples, no measurable verotoxin was found in finely ground lean beef which had been inoculated with 10(4.8) CFU of E. coli O157:H7 per g, irradiated at a minimum dose of 1.5 kGy, and temperature abused at 35 degrees C for 20 h. Irradiation is an effective method to control this food-borne pathogen

Affinity isolation and I-DIRT mass spectrometric analysis of the Escherichia coli O157:H7 Sakai RNA polymerase complex.

Science.gov (United States)

Lee, David J; Busby, Stephen J W; Westblade, Lars F; Chait, Brian T

2008-02-01

Bacteria contain a single multisubunit RNA polymerase that is responsible for the synthesis of all RNA. Previous studies of the Escherichia coli K-12 laboratory strain identified a group of effector proteins that interact directly with RNA polymerase to modulate the efficiency of transcription initiation, elongation, or termination. Here we used a rapid affinity isolation technique to isolate RNA polymerase from the pathogenic Escherichia coli strain O157:H7 Sakai. We analyzed the RNA polymerase enzyme complex using mass spectrometry and identified associated proteins. Although E. coli O157:H7 Sakai contains more than 1,600 genes not present in the K-12 strain, many of which are predicted to be involved in transcription regulation, all of the identified proteins in this study were encoded on the "core" E. coli genome.

Survival of bioluminescent Listeria monocytogenes and Escherichia coli O157:H7 in soft cheeses.

Science.gov (United States)

Ramsaran, H; Chen, J; Brunke, B; Hill, A; Griffiths, M W

1998-07-01

Pasteurized and raw milks that had been inoculated at 10(4) cfu/ml with bioluminescent strains of Listeria monocytogenes and Escherichia coli O157:H7 were used in the manufacture of Camembert and Feta cheeses with or without nisin-producing starter culture. Survival of both organisms was determined during the manufacture and storage of Camembert and Feta cheeses at 2 +/- 1 degree C for 65 and 75 d, respectively. Bacterial bioluminescence was used as an indicator to enumerate the colonies plated on selective Listeria agar and on MacConkey agar. Escherichia coli O157:H7 survived the manufacturing process of both cheeses and was present at the end of the storage period in greater numbers than in the initial inoculum. At the end of 75 d of storage, E. coli O157:H7 was found in the brine of Feta cheese. The counts of L. monocytogenes increased as the pH of the Camembert cheese increased, and there were significant differences between the counts from samples taken from the inside and the counts from samples obtained near the surface of the cheese. The Feta cheese that contained nisin was the only cheese in which L. monocytogenes was at the level of the initial inoculum after 75 d of storage.

21 CFR 866.3255 - Escherichia coli serological reagents.

Science.gov (United States)

2010-04-01

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

Determination of gamma radiation dose to the destruction of Escherichia coli O157: H7 in hamburger

International Nuclear Information System (INIS)

Orejuela Chirinos, Rodolfo Raul

1999-01-01

Escherichia coli O157:H7 has been incriminated in several foodborne outbreaks due to the consumption of different kinds of foods. Among these, hamburgers are the most common. Irradiation process is an effective method for food preservation because it causes no significant change in organoleptic and nutritional food characteristics and destroys pathogens and spoilage microorganisms. Hamburgers and nutrient broth inoculated with Escherichia coli O157:H7 were submitted to gamma irradiation ( 60 Co) treatment, with doses ranging from 0,0 to 0,7 kGy in order to calculate the D 10 for this bacteria in these substrate. The D 10 for the pathogen nutrient broth ranged from 0.08 kGy to 0.10 kGy and in hamburger from 0.11 kGy to 0.21 kGy. Considering the highest D 10 value in hamburger, a dose of 0,8 kGy would not change the sensorial characteristics of the product, and would reduce the population of E. coli O157:H7 in 4 cycles logarithmic. (author)

Deuterium incorporation into Escherichia-coli proteins

DEFF Research Database (Denmark)

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

1986-01-01

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

Escherichia coli verotoxigênica: isolamento e prevalência em 60 propriedades de bovinos de leite da região de Pelotas, RS, Brasil Verotoxin-producing Escherichia coli: isolation and prevalence in 60 dairy cattle farms from Pelotas-RS, Brazil

Directory of Open Access Journals (Sweden)

Cecília Nunes Moreira Sandrini

2007-02-01

Full Text Available A produção de verotoxinas foi investigada em 1.127 isolamentos de Escherichia coli feitos a partir de 243 bovinos de leite, de água de consumo humano e animal e de amostras de leite de 60 propriedades da bacia leiteira de Pelotas, no período de dezembro de 1999 a dezembro de 2000, com o objetivo de determinar a prevalência de E. coli verotoxigênicas (VTEC nas propriedades e no rebanho, de detectar a presença de sorotipos ligados a infecções humanas e de identificar, nas propriedades e na região de Pelotas, potenciais fatores de risco de infecção para os animais. A detecção das toxinas em sobrenadante de culturas de E. coli isoladas foi realizada através do ensaio de citotoxicidade em células Vero. VTEC foi isolada em 95% (57/60 das propriedades estudadas, em 49% (119/243 dos animais testados, em 5% (3/60 das amostras de água de consumo humano, em 8,35% (5/60 das amostras de água de consumo animal e em 5% (3/60 das amostras de leite. A prevalência de bovinos infectados em cada propriedade variou de 0 a 100%. Em 2,9% (7/243 dos animais testados, foram isoladas VTEC pertencentes aos sorogrupos O157, O91 e O112, que incluem cepas responsáveis por casos de colite hemorrágica e síndrome urêmica hemolítica em humanos. Fatores de risco de contaminação, como a precipitação pluviométrica, a temperatura, o tamanho da propriedade e a concentração de animais, apresentaram evidências de influenciarem a prevalência de VTEC nos animais. Estes resultados sugerem que o grupo VTEC está amplamente distribuído na bacia leiteira de Pelotas e inclui organismos pertencentes a sorogrupos patogênicos para humanos.The production of verotoxin was investigated in 1127 Escherichia coli isolated from 243 dairy cattle, water for human and animal consumption, and milk samples from 60 dairy farms from Pelotas-Brazil, from December of 1999 to December of 2000, to determine the prevalence of verotoxigenic E. coli (VTEC in farms, to detect the

Antimicrobial effect of Al2O3, Ag and Al2O3/Ag thin films on Escherichia coli and Pseudomonas putida

International Nuclear Information System (INIS)

Angelov, O; Stoyanova, D; Ivanova, I; Todorova, S

2016-01-01

The influence of Al 2 O 3 , Ag and Al 2 O 3 /Ag thin films on bacterial growth of Gramnegative bacteria Pseudomonas putida and Escherichia coli is studied. The nanostructured thin films are deposited on glass substrates without intentional heating through r.f. magnetron sputtering in Ar atmosphere of Al 2 O 3 and Ag targets or through sequential sputtering of Al 2 O 3 and Ag targets, respectively. The individual Ag thin films (thickness 8 nm) have a weak bacteriostatic effect on Escherichia coli expressed as an extended adaptive phase of the bacteria up to 5 hours from the beginning of the experiment, but the final effect is only 10 times lower bacterial density than in the control. The individual Al 2 O 3 film (20 nm) has no antibacterial effect against two strains E. coli - industrial and pathogenic. The Al 2 O 3 /Ag bilayer films (Al 2 O 3 20 nm/Ag 8 nm) have strong bactericidal effect on Pseudomonas putida and demonstrate an effective time of disinfection for 2 hours. The individual films Al2O3 and Ag have not pronounced antibacterial effect on Pseudomonas putida . A synergistic effect of Al2O3/Ag bilayer films in formation of oxidative species on the surface in contact with the bacterial suspension could be a reason for their antimicrobial effect on E. coli and P. putida . (paper)

Prevalence and Genomic Characterization of Escherichia coli O157:H7 in Cow-Calf Herds throughout California.

Science.gov (United States)

Worley, Jay N; Flores, Kristopher A; Yang, Xun; Chase, Jennifer A; Cao, Guojie; Tang, Shuai; Meng, Jianghong; Atwill, Edward R

2017-08-15

Escherichia coli serotype O157:H7 is a zoonotic food- and waterborne bacterial pathogen that causes a high hospitalization rate and can cause life-threatening complications. Increasingly, E. coli O157:H7 infections appear to originate from fresh produce. Ruminants, such as cattle, are a prominent reservoir of E. coli O157:H7 in the United States. California is one of the most agriculturally productive regions in the world for fresh produce, beef, and milk. The close proximity of fresh produce and cattle presents food safety challenges on a uniquely large scale. We performed a survey of E. coli O157:H7 on 20 farms in California to observe the regional diversity and prevalence of E. coli O157:H7. Isolates were obtained from enrichment cultures of cow feces. Some farms were sampled on two dates. Genomes from isolates were sequenced to determine their relatedness and pathogenic potential. E. coli O157:H7 was isolated from approximately half of the farms. The point prevalence of E. coli O157:H7 on farms was highly variable, ranging from zero to nearly 90%. Within farms, generally one or a few lineages were found, even when the rate of isolation was high. On farms with high isolation rates, a single clonal lineage accounted for most of the isolates. Farms that were visited months after the first visit might have had the same lineages of E. coli O157:H7. Strains of E. coli O157:H7 may be persistent for months on farms. IMPORTANCE This survey of 20 cow-calf operations from different regions of California provides an in depth look at resident Escherichia coli O157:H7 populations at the molecular level. E. coli O157:H7 is found to have a highly variable prevalence, and with whole-genome sequencing, high prevalences in herds were found to be due to a single lineage shed from multiple cows. Few repeat lineages were found between farms in this area; therefore, we predict that E. coli O157:H7 has significant diversity in this area beyond what is detected in this survey. All

Immunoconcentration of Shiga toxin-producing Escherichia coli O157 from animal faeces and raw meats by using Dynabeads anti-E. coli O157 and the VIDAS system

NARCIS (Netherlands)

Islam, M.A.; Heuvelink, A.E.; Talukder, K.A.; Boer, de E.

2006-01-01

To identify the reservoirs and routes of transmission of Shiga toxin-producing Escherichia coli (STEC) O157, sensitive detection and isolation methods are necessary. The sensitivity of traditional culture methods can be improved significantly by the inclusion of an immunoconcentration step,

Reducing of escherichia coli O 157 serotype and cohabitant flora by irradiation in minced meat

International Nuclear Information System (INIS)

Halkman, A.K.; Dogan, H.B.; Yazici, N.

2001-01-01

Escherichia coli O157:H7 was conclusively identified as a pathogen in 1982 following its association with two food-related outbreaks of an unusual gastrointestinal illness. The infectious dose of E. coli O157 is very low, and as a result the organism can be transmitted efficiently not only via contaminated foods but also person to person (Doyle 1991, Karch et al. 1996). Although not definitely linked, consumption of undercooked meats and mainly hamburgers has been strongly implicated in hemorrhagic uremic colitis and hemolytic uremic syndrome. Water and unpasteurized milk are also recognized as sources of outbreaks (Yu and Bruno 1996 , Venkateswaran et al. 1997). Meat and milk products are the most important foods for E. coli O157:H7 outbreaks. Apple cider, drinking and swimming waters are also important for outbreaks. Literature reveals that E. coli O157:H7 is not resistant to the application of radiations. Gamma rays obtained from ''6''0Co ve ''1''3''7Gs sources find wide application in the food protection as these rays eliminate various pathogen including E.coli O157:H7 in the solid foods. Irradiation of food is less effective at temperature below freezing point. In USA beef is allowed to prevent E.coli O157:H7 infection (Farkas et al.1998;Fujikawa et al.1992; Harewood et al.1994;Park et al.1999)

Selection of antibiotics in detection procedure of Escherichia coli O157:H7 in vegetables

Science.gov (United States)

Hoang, Hoang A.; Nhung, Nguyen T. T.

2017-09-01

Detection of Escherichia coli O157:H7 in ready-to-eat fresh vegetables is important since this bacteria is considered as one of the most important pathogens in relation to public health. However, it could be a big challenge for detection of initial low concentrations of E. coli O157:H7 in the samples. In this study, selection of antibiotics that suppress growth of background bacteria to enable detection of E. coli O157:H7 in ready-to-eat fresh vegetables was investigated. Firstly, different combinations of two antibiotics, i.e. novobiocin (N) and vancomycin (V), in BHI broth were conducted. The three antibiotic combinations were preliminary examined their effect on the growth of E. coli O157:H7 and Bacillus spp. in broth based on OD600nm measurement. The combination of both the antibiotics was selected to examine their possibility to support detection of E. coli O157:H7 in vegetables. It was successful when two antibiotics showed their support in detection of E. coli O157:H7 at very low concentration of 2 CFU per one gram of lettuce. Usage of these antibiotics is simple and cheap in the detection procedure and could be applied to other types of ready-to-eat fresh vegetables popular in Vietnam.

Synergistic interaction in dual-species biofilms formation by Escherichia coli O157:H7 and Ralstonia spp

Science.gov (United States)

Introduction: Ralstonia spp., a heterotrophic bacterium that are isolated from produce processing environments as part of the native microflora, have strong potentials for formaing biofilms on various surfaces. When co-cultured, Escherichia coli O157:H7 (EcO157) and Ralstonia spp. displayed a synerg...

Affinity Isolation and I-DIRT Mass Spectrometric Analysis of the Escherichia coli O157:H7 Sakai RNA Polymerase Complex▿

Science.gov (United States)

Lee, David J.; Busby, Stephen J. W.; Westblade, Lars F.; Chait, Brian T.

2008-01-01

Bacteria contain a single multisubunit RNA polymerase that is responsible for the synthesis of all RNA. Previous studies of the Escherichia coli K-12 laboratory strain identified a group of effector proteins that interact directly with RNA polymerase to modulate the efficiency of transcription initiation, elongation, or termination. Here we used a rapid affinity isolation technique to isolate RNA polymerase from the pathogenic Escherichia coli strain O157:H7 Sakai. We analyzed the RNA polymerase enzyme complex using mass spectrometry and identified associated proteins. Although E. coli O157:H7 Sakai contains more than 1,600 genes not present in the K-12 strain, many of which are predicted to be involved in transcription regulation, all of the identified proteins in this study were encoded on the “core” E. coli genome. PMID:18083804

Molecular and Phenotypic Characterization of Escherichia coli O26:H8 among Diarrheagenic E. coli O26 Strains Isolated in Brazil

Science.gov (United States)

Piazza, Roxane M. F.; Delannoy, Sabine; Fach, Patrick; Saridakis, Halha O.; Pedroso, Margareth Z.; Rocha, Letícia B.; Gomes, Tânia A. T.; Vieira, Mônica A. M.; Beutin, Lothar

2013-01-01

Escherichia coli strains of serogroup O26 comprise two distinct groups of pathogens, characterized as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC). Among the several genes related to type III secretion system-secreted effector proteins, espK was found to be highly specific for EHEC O26:H11 and its stx-negative derivative strains isolated in European countries. E. coli O26 strains isolated in Brazil from infant diarrhea, foods, and the environment have consistently been shown to lack stx genes and are thus considered atypical EPEC. However, no further information related to their genetic background is known. Therefore, in this study, we aimed to discriminate and characterize these Brazilian O26 stx-negative strains by phenotypic, genetic, and biochemical approaches. Among 44 isolates confirmed to be O26 isolates, most displayed flagellar antigen H11 or H32. Out of the 13 nonmotile isolates, 2 tested positive for fliCH11, and 11 were fliCH8 positive. The identification of genetic markers showed that several O26:H11 and all O26:H8 strains tested positive for espK and could therefore be discriminated as EHEC derivatives. The presence of H8 among EHEC O26 and its stx-negative derivative isolates is described for the first time. The interaction of three isolates with polarized Caco-2 cells and with intestinal biopsy specimen fragments ex vivo confirmed the ability of the O26 strains analyzed to cause attaching-and-effacing (A/E) lesions. The O26:H32 strains, isolated mostly from meat, were considered nonvirulent. Knowledge of the virulence content of stx-negative O26 isolates within the same serotype helped to avoid misclassification of isolates, which certainly has important implications for public health surveillance. PMID:23974139

Gene Expression during Survival of Escherichia coli O157:H7 in Soil and Water

Directory of Open Access Journals (Sweden)

Ashley D. Duffitt

2011-01-01

Full Text Available The in vitro survival of Escherichia coli O157:H7 at 15∘C under two experimental conditions (sterile soil and sterile natural water was examined. DNA microarrays of the entire set of E. coli O157:H7 genes were used to measure the genomic expression patterns after 14 days. Although the populations declined, some E. coli O157:H7 cells survived in sterile stream water up to 234 days and in sterile soil for up to 179 days. Cells incubated in soil microcosms for 14 days expressed genes for antibiotic resistance, biosynthesis, DNA replication and modification, metabolism, phages, transposons, plasmids, pathogenesis and virulence, antibiotic resistance, ribosomal proteins, the stress response, transcription, translation, and transport and binding proteins at significantly higher levels than cells grown in Luria broth. These results suggest that E. coli O157:H7 may develop a different phenotype during transport through the environment. Furthermore, this pathogen may become more resistant to antibiotics making subsequent infections more difficult to treat.

Plant lesions promote the rapid multiplication of Escherichia coli O157:H7 on post-harvest lettuce

Science.gov (United States)

Several outbreaks of Escherichia coli O157:H7 (EcO157) infections have been associated with minimally processed leafy vegetables in the U.S. Harvesting and processing cause plant tissue damage. In order to assess the role of plant tissue damage in the contamination of leafy greens with EcO157, the e...

Fate of Escherichia coli O157: H7 in agricultural soils amended with different organic fertilizers.

Science.gov (United States)

Yao, Zhiyuan; Yang, Li; Wang, Haizhen; Wu, Jianjun; Xu, Jianming

2015-10-15

Five organic fertilizers (vermicompost, pig manure, chicken manure, peat and oil residue) were applied to agricultural soils to study their effects on the survival of Escherichia coli O157:H7 (E. coli O157:H7). Results showed that E. coli O157:H7 survival changed greatly after organic fertilizers application, with shorter td values (survival time needed to reach the detection limit of 100 CFU g(-1)) (12.57±6.57 days) in soils amended with chicken manure and the longest (25.65±7.12 days) in soils amended with pig manure. Soil pH, EC and free Fe/Al (hydro) oxides were significant explanatory factors for E. coli O157:H7 survival in the original soils. Soil constituents (minerals and organic matter) and changes in their surface charges with pH increased the effect of soil pH on E. coli O157:H7 survival. However, electrical conductivity played a more important role in regulating E. coli O157:H7 survival in fertilizer-amended soils. This study highlighted the importance of choosing appropriate organic fertilizers in the preharvest environment to reduce food-borne bacterial contamination. Copyright © 2015 Elsevier B.V. All rights reserved.

Antibacterial activity against Escherichia coli and characterization of ZnO and ZnO–Al2O3 mixed oxide nanoparticles

Directory of Open Access Journals (Sweden)

Ertan Şahin

2017-02-01

Full Text Available In order to achieve better antibacterial water insoluble nanoparticles (Nanoparticles of ZnO and ZnO–Al2O3 were studied. ZnO–Al2O3 mixed oxide nanoparticles were produced from a solution containing Zn(AC2⋅2H2O and AlCl3 by Solvothermal method. The calcination process of the ZnO–Al2O3 composite nanoparticles brought forth polycrystalline one phase ZnO–Al2O3 nanoparticles of 30–50 nm in diameters. ZnO and ZnO–Al2O3 were crystallized into würtzite and rock salt structures, respectively. The structural properties of this sample were analyzed by XRD and compared with bulk case of these samples. Antibacterial effectiveness of the ZnO and ZnO–Al2O3 nanoparticles were tested against general Escherichia coli (E. coli ATCC 25922 and E. coli O157:H7 by measuring the growth through optical density and digital counting of live–dead cells. Minimum inhibitory concentration values against four representative bacteria along with E. coli O157:H7 were also obtained.

O6-methylguanine-DNA methyltransferase in wild-type and ada mutants of Escherichia coli

International Nuclear Information System (INIS)

Mitra, S.; Pal, B.C.; Foote, R.S.

1982-01-01

O 6 -Methylguanine-DNA methyltransferase is induced in Escherichia coli during growth in low levels of N-methyl-N'-nitro-N-nitrosoguanidine. We have developed a sensitive assay for quantitating low levels of this activity with a synthetic DNA substrate containing 3 H-labeled O 6 -methylguanine as the only modified base. Although both wild-type and adaptation-deficient (ada) mutants of E. coli contained low but comparable numbers (from 13 to 60) of the enzyme molecules per cell, adaptation treatment caused a significant increase of the enzyme in the wild type but not in the ada mutants, suggesting that the ada mutation is in a regulatory locus and not in the structural gene for the methyltransferase

Prevalence of Avian Pathogenic Escherichia coli (APEC Clone Harboring sfa Gene in Brazil

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Terezinha Knöbl

2012-01-01

Full Text Available Escherichia coli sfa+ strains isolated from poultry were serotyped and characterized by polymerase chain reaction (PCR and amplified fragment length polymorphism (AFLP. Isolates collected from 12 Brazilian poultry farms mostly belonged to serogroup O6, followed by serogroups O2, O8, O21, O46, O78, O88, O106, O111, and O143. Virulence genes associated were: iuc 90%, fim 86% neuS 60%, hly 34%, tsh 28%, crl/csg 26%, iss 26%, pap 18%, and 14% cnf. Strains from the same farm presented more than one genotypic pattern belonging to different profiles in AFLP. AFLP showed a clonal relation between Escherichia coli sfa+ serogroup O6. The virulence genes found in these strains reveal some similarity with extraintestinal E. coli (ExPEC, thus alerting for potential zoonotic risk.

Antimicrobial Activities of TiO2 Nanoparticle Against Escherichia coli and Staphylococcus aureus

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F Barzegary

2010-04-01

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

Antibiotic resistance of Verotoxigenic Escherichia coli isolated from vegetables

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mojtaba boniadian

2017-01-01

Full Text Available Introduction: Human gastrointestinal disease caused by verotoxigenic Escherichia coli has been diagnosed for recent decades. Escherichia coli O157:H7 is the most important serotype of verotoxigenic Escherichia coli that cause hemolytic uremic syndrome and hemorrhagic colitis in humans. This study was conducted to determine the occurrence of verotoxigenic E. coli and antibiotic resistance of the isolates from vegetables. Materials and methods: A total of 500 fresh vegetable samples were collected randomly from retail shops in Shahrekord, Iran. E. coli was isolated and identified using bacteriological and biochemical tests. PCR method was used to identify the rbfE, stx1, stx2 and eae genes. Also, antibiotic resistance of the isolates was determined by disk diffusion method. Results: The results represented that among 25 isolates possess virulence genes, 40, 12 and 4% of the isolates contained eaeA, STx2, and both genes, respectively. But none of them contained H7, STx1, and rfbE genes. The antibiotic resistance pattern demonstrated that the isolates were highly resistant to Gentamycin and cefotoxime. Discussion and conclusion: The results of this study showed that the presence of verotoxigenic E.coli in vegetables; and high resistance of the isolates to antibiotics could be hazardous for public health.

ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli ANALISIS CEMARAN BAKTERI Escherichia coli

OpenAIRE

ANGGREINI, RAHAYU

2015-01-01

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

Isolation and evaluation of cocktail phages for the control of multidrug-resistant Escherichia coli serotype O104: H4 and E. coli O157: H7 isolates causing diarrhea.

Science.gov (United States)

Safwat Mohamed, Doaa; Farouk Ahmed, Eman; Mohamed Mahmoud, Abobakr; Abd El-Baky, Rehab Mahmoud; John, James

2018-02-01

Escherichia coli serotype O157: H7 and E. coli O104: H4 are well known foodborne pathogens causing sever enteric illness. Using bacteriophages as biocontrol agents of some foodborne pathogens and multidrug-resistant (MDR) bacteria has a great attention nowadays. This study aims to test the effect of cocktail phages on the growth of some foodborne pathogens and MDR E. coli. Routine conventional PCR was used to confirm the identification of E. coli isolates. Double-layered culture technique was used to isolate phages from sewage water. Morphology of bacteriophage was described using transmission electron microscopy, and spot test was performed to determine host range of the phage cocktail. Phage cocktail of Siphoviridae and Podoviridae family infecting E. coli O157: H7, E. coli O104: H4 and untypeable E. coli (neither O157 nor O104) has been isolated from sewage water. Phage cocktail showed both lytic and lysogenic activity. Lytic activity was observed against E. coli O157: H7, E. coli O104: H4 isolates, Staphylococcus. aureus ATCC6538 and Pseudomonas aeruginosa ATCC 10145, while the lysogenic activity was observed against the untypeable strain. The tested phage cocktail showed a promising inhibitory action on E. coli O157: H7 and O104: H4, S. aureus ATCC6538 and P. aeruginosa ATCC 10145, suggesting the possibility of its use as a biocontrol tool or as natural food preservatives for many food products. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

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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.

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

African Journals Online (AJOL)

Administrator

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

Inhibition of Escherichia Coli, Salmonella and Staphylococcus ...

African Journals Online (AJOL)

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

An aptamer-based biosensor for colorimetric detection of Escherichia coli O157:H7.

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Wenhe Wu

Full Text Available BACKGROUND: An aptamer based biosensor (aptasensor was developed and evaluated for rapid colorimetric detection of Escherichia coli (E. coli O157:H7. METHODOLOGY/PRINCIPAL FINDINGS: The aptasensor was assembled by modifying the truncated lipopolysaccharides (LPS-binding aptamer on the surface of nanoscale polydiacetylene (PDA vesicle using peptide bonding between the carboxyl group of the vesicle and the amine group of the aptamer. Molecular recognition between E. coli O157:H7 and aptamer at the interface of the vesicle lead to blue-red transition of PDA which was readily visible to the naked eyes and could be quantified by colorimetric responses (CR. Confocal laser scanning microscope (CLSM and transmission electron microscopy (TEM was used to confirm the specific interactions between the truncated aptamer and E. coli O157:H7. The aptasensor could detect cellular concentrations in a range of 10(4~ 10(8 colony-forming units (CFU/ml within 2 hours and its specificity was 100% for detection of E. coli O157:H7. Compared with the standard culture method, the correspondent rate was 98.5% for the detection of E. coli O157:H7 on 203 clinical fecal specimens with our aptasensor. CONCLUSIONS: The new aptasensor represents a significant advancement in detection capabilities based on the combination of nucleic acid aptamer with PDA vesicle, and offers a specific and convenient screening method for the detection of pathogenic bacteria. This technic could also be applied in areas from clinical analysis to biological terrorism defense, especially in low-resource settings.

FTIR nanobiosensors for Escherichia coli detection

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Stefania Mura

2012-07-01

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

Escherichia coli enteroagregativa como agente provocador de diarreia persistente: modelo experimental utilizando microscopia óptica de luz Escherichia coli enteroagregativa como agente provocador de diarrea persistente: modelo experimental utilizando microscopia óptica de luz Enteroaggregative Escherichia coli as a cause of persistent diarrhea: an experimental model using light microscopy

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Jacy Alves B. de Andrade

2011-03-01

Full Text Available OBJETIVO: Avaliar interações de amostras de Escherichia coli enteroagregativa com tecido intestinal humano, a fim de documentar potenciais alterações em diferentes regiões do trato digestivo. MÉTODOS: Amostras de Escherichia coli enteroagregativa isoladas das fezes de crianças com diarreia persistente e a amostra protótipo 042, isolada de uma criança com diarreia em Lima, no Peru (controle positivo, foram analisadas por microscopia óptica de luz após semeadura em cultura de orgão in vitro de fragmentos de mucosa ileal e colônica. Foram analisadas as interações entre as diferentes cepas de Escherichia coli enteroagregativa e as mucosas ileal e colônica. RESULTADOS: A análise por microscopia óptica de luz indicou associação destes micro-organismos com o epitélio, provocando alterações. As cepas estudadas aderiram a ambas as regiões avaliadas (intestino delgado distal e grosso e causaram alterações, especialmente naquelas áreas onde interagiram diretamente com o epitélio. No íleo, algumas regiões mostraram internalização secundária. CONCLUSÕES: Esses agentes podem causar diarreia persistente por meio de alterações no intestino delgado, no qual ocorrem as funções digestivo-absortivas. As lesões inflamatórias descritas na mucosa colônica poderiam explicar a colite mostrada em algumas crianças infectadas por Escherichia coli enteroagregativa.OBJETIVO: Evaluar interacciones de muestras de Escherichia coli enteroagregativa (EAEC con tejido intestinal humano, a fin de documentar potenciales alteraciones en distintas regiones del tracto digestivo (intestino delgado distal e intestino grueso y definir, con eso, su rol en la persistencia del proceso diarreico. MÉTODOS: Muestras de EAEC aislada de las heces de niños con diarrea persistente y la muestra prototipo 042, aislada de un niño con diarrea en Lima, Perú (control positivo fueron analizadas por microscopía óptica de luz (ML después de siembra en cultura

Shiga toxin-producing Escherichia coli (STEC) O22:H8 isolated from cattle reduces E. coli O157:H7 adherence in vitro and in vivo.

Science.gov (United States)

Martorelli, L; Albanese, A; Vilte, D; Cantet, R; Bentancor, A; Zolezzi, G; Chinen, I; Ibarra, C; Rivas, M; Mercado, E C; Cataldi, A

2017-09-01

Shiga toxin-producing Escherichia coli (STEC) are a group of bacteria responsible for food-associated diseases. Clinical features include a wide range of symptoms such as diarrhea, hemorrhagic colitis and the hemolytic uremic syndrome (HUS), a life-threatening condition. Our group has observed that animals naturally colonized with STEC strains of unknown serotype were not efficiently colonized with E. coli O157:H7 after experimental infection. In order to assess the basis of the interference, three STEC strains were isolated from STEC persistently-colonized healthy cattle from a dairy farm in Buenos Aires, Argentina. The three isolated strains are E. coli O22:H8 and carry the stx1 and stx2d genes. The activatable activity of Stx2d was demonstrated in vitro. The three strains carry the adhesins iha, ehaA and lpf O113 . E. coli O22:H8 formed stronger biofilms in abiotic surface than E. coli O157:H7 (eae+, stx2+) and displayed a more adherent phenotype in vitro towards HeLa cells. Furthermore, when both serotypes were cultured together O22:H8 could reduce O157:H7 adherence in vitro. When calves were intragastrically pre-challenged with 10 8 CFU of a mixture of the three STEC strains and two days later challenged with the same dose of the strain E. coli O157:H7 438/99, the shedding of the pathogen was significantly reduced. These results suggest that E. coli O22:H8, a serotype rarely associated with human illness, might compete with O157:H7 at the bovine recto-anal junction, making non-O157 carrying-calves less susceptible to O157:H7 colonization and shedding of the bacteria to the environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Escherichia coli O157:H7 Outbreak Associated with Restaurant Beef Grinding.

Science.gov (United States)

Torso, Lauren M; Voorhees, Ronald E; Forest, Stephen A; Gordon, Andrew Z; Silvestri, Sharon A; Kissler, Bonnie; Schlackman, Jessica; Sandt, Carol H; Toma, Paul; Bachert, Joel; Mertz, Kristen J; Harrison, Lee H

2015-07-01

Escherichia coli O157:H7 is a common cause of foodborne illness in the United States. Beef ground at establishments regulated by the U.S. Department of Agriculture, Food Safety and Inspection Service is routinely tested for E. coli O157:H7. Prior to December 2013, boxed beef product (wholesale cuts of beef, such as beef loin, packaged into bags and boxed for shipping) was not always tested for this pathogen. Downstream processors or retailers may grind the product; and, if the ground beef is not cooked to the recommended temperature, pathogens on the exterior of the beef introduced to the interior through grinding may survive. On 18 October 2013, the Allegheny County Health Department identified two E. coli O157:H7 cases, both of whom were food handlers at restaurant A, a restaurant that ground locally produced boxed beef for hamburgers on site. Case finding was conducted through public messaging, employee surveys, and disease surveillance. All potential cases were interviewed using a standard questionnaire. A confirmed case was defined as laboratory-confirmed E. coli O157:H7 with exposure to restaurant A. A probable case was defined as a patient with compatible symptoms and exposure to restaurant A but without laboratory confirmation. All human and food isolates were characterized by pulsed-field gel electrophoresis and multilocus variable-number tandem repeat analysis. The analysis identified 14 confirmed and 10 probable cases of E. coli; 18 nonintact ground beef samples tested positive for E. coli O157:H7. Nine confirmed cases were restaurant A employees. All confirmed cases recalled eating a restaurant A hamburger in the 10 days before illness onset; most cases reported consuming medium to rare hamburgers. Multiple pulsed-field gel electrophoresis and multilocus variable-number tandem repeat analysis patterns were identified among both the human and ground beef isolates, and the patient isolates matched those found in ground beef samples. Restaurant A

Bovine milk fat globule membrane affects virulence expression in Escherichia coli O157:H7.

Science.gov (United States)

Tellez, A; Corredig, M; Guri, A; Zanabria, R; Griffiths, M W; Delcenserie, V

2012-11-01

The aim of this study was to examine the effect of the bovine milk fat globule membrane (MFGM) on the virulence of Escherichia coli O157:H7. The MFGM was extracted from raw or heat-treated milk, resulting in 2 preparations differing in protein composition. Both heated and raw MFGM exerted an inhibitory effect on Shiga toxin gene expression by E. coli O157:H7 (ratios of -7.69 and -5.96, respectively). Interestingly, the effect was stronger with heated MFGM, with a larger decrease in expression of the virulence gene fliC (ratio of -9.43). The difference in effect observed between heated and raw MFGM could be explained by the difference in protein composition between the 2 preparations. These results show, for the first time, a specific effect of MFGM on expressionof Shiga toxin genes as well as genes involved in the motility of E. coli O157:H7. This may offer a new approach to mitigate the adverse health effects caused by E. coli O157:H7 infections. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

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 ...

Assessment of the efficiency of ColiSure™ for coliforms Escherichia coli enumeration in pasteurizad milk / Avaliação do desempenho do ColiSure™ na enumeração de coliformes totais e Escherichia coli em leite pasteurizado

Directory of Open Access Journals (Sweden)

Elsa Helena Walter de Santana

2000-12-01

Full Text Available In the dairy industry the coliforms detection can he used as indicative of hygiene production of the raw milk and the contamination after-pasteurization. The traditional methods for the enumeration of the total and faecal coliforms are laborious and needs an incubation time of 96 hours. Rapid methods for detection of these microorganisms have been developed and among them the ColsSuroit is a rapid method that gives results in 24 hours and involves defined substrates for simultaneous determination of total conforms and E. coli in water based in specific enzymatic reactions of these microorganisms. The objective of this study was to evaluate its utilization in milk. Ninety-five samples of pasteurized milk were collected from the markets in Londrina city, Parana and analyzed by the Most Probable Number (NMP enumeration using the Brilliant Green Bile Lactose Broth (BGBL and ColiSure™. There was a correlation of 0.80 betwee-n the mediums when the incubation time was 43 hours for total conforms. The low down occurrence of E. coffin the analyzed samples made impossible to comparate the performance of methods for this microorganism. Compfementary analysis showed a greater sensibility and especifity of the ColiSure™ in comparation with the BGBL. The CofiSure™ can be indicated as a substitute for the traditional method, with the advantage to be faster and easier.Na indústria láctea a detecção de microrganismos do grupo coliformes é utilizada como indicativo da higiene na produção do leite e de contaminação pós-pasteurizaçüo. Os métodos tradicionais para a enumeração de coliformes totais e fecais são trabalhosos, com tempo de incubação longo, de até 96 horas. Métodos rápidos para a detecção destes microrganismos têm sido desenvolvidos na área de microbiologia de alimentos. O ColiSure™ é um método rápido, que fornece resultados simultaneamente para a presença ou a ausência de coliformes totais e Escherichia coli em �

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

African Journals Online (AJOL)

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

Detection of Shiga toxin-producing Escherichia coli (STEC) O157:H7, O26, O45, O103, O111, O121, and O145, and Salmonella in retail raw ground beef using the DuPont™ BAX® system.

Science.gov (United States)

Wasilenko, Jamie L; Fratamico, Pina M; Sommers, Christopher; DeMarco, Daniel R; Varkey, Stephen; Rhoden, Kyle; Tice, George

2014-01-01

Shiga toxin-producing Escherichia coli (STEC) and Salmonella are food-borne pathogens commonly associated with beef, and reliable methods are needed to determine their prevalence in beef and to ensure food safety. Retail ground beef was tested for the presence of E. coli O157:H7, STEC serogroups O26, O45, O103, O111, O121, and O145, and Salmonella using the DuPont™ BAX® system method. Ground beef (325 g) samples were enriched in 1.5 L of TSB with 2 mg/L novobiocin at 42°C for 18 h, and then evaluated using the BAX® System real-time PCR assays for E. coli O157:H7 and STEC suite, and the BAX® System standard PCR assays for E. coli O157:H7 MP and Salmonella. Samples positive for STEC target genes by the BAX® System assays were subjected to immunomagnetic separation (IMS) and plating onto modified Rainbow Agar O157. Enrichments that were PCR positive for Salmonella were inoculated into RV broth, incubated for 18 h at 42°C, and then plated onto XLT-4 agar. Presumptive positive STEC and Salmonella colonies were confirmed using the BAX® System assays. Results of the BAX® System STEC assays showed 20/308 (6.5%) of samples positive for both the Shiga toxin (stx) and intimin (eae) genes; 4 (1.3%) for stx, eae, and O26; 1 (0.3%) for stx, eae, and O45; 3 (1%) for stx, eae, and O103; and 1 (0.3%) for stx, eae, and O145. There were also 3 samples positive for stx, eae, and more than one STEC serogroup. Three (1.0%) of the samples were positive using the BAX® System real-time E. coli O157:H7 assay, and 28 (9.1%) were positive using the BAX® System Salmonella assay. STEC O103 and E. coli O157:H7 were isolated from 2/6 and 2/3 PCR positive samples, respectively. Salmonella isolates were recovered and confirmed from 27 of the 28 Salmonella PCR positive samples, and a portion of the isolates were serotyped and antibiotic resistance profiles determined. Results demonstrate that the BAX® System assays are effective for detecting STEC and Salmonella in beef.

Transcription factor DecR (YbaO) controls detoxification of L-cysteine in Escherichia coli.

Science.gov (United States)

Shimada, Tomohiro; Tanaka, Kan; Ishihama, Akira

2016-09-01

YbaO is an uncharacterized AsnC-family transcription factor of Escherichia coli. In both Salmonella enterica and Pantoea ananatis, YbaO homologues were identified to regulate the adjacent gene encoding cysteine desulfhydrase for detoxification of cysteine. Using the genomic SELEX (systematic evolution of ligands by exponential enrichment) screening system, we identified the yhaOM operon, located far from the ybaO gene on the E. coli genome, as a single regulatory target of YbaO. In both gel shift assay in vitro and reporter and Northern blot assays in vivo, YbaO was found to regulate the yhaOM promoter. The growth of mutants lacking either ybaO or its targets yhaOM was delayed in the presence of cysteine, indicating involvement of these genes in cysteine detoxification. In the major pathway of cysteine degradation, hydrogen sulfide is produced in wild-type E. coli, but its production was not observed in each of the ybaO, yhaO and yhaM mutants. The yhaOM promoter was activated in the presence of cysteine, implying the role of cysteine in activation of YbaO. Taken together, we propose that YbaO is the cysteine-sensing transcriptional activator of the yhaOM operon, which is involved in the detoxification of cysteine. We then propose the naming of ybaO as decR (regulator of detoxification of cysteine).

Fate of naturally occurring Escherichia coli O157:H7 and other zoonotic pathogens during minimally managed bovine feedlot manure composting processes

Science.gov (United States)

Reducing Escherichia coli O157:H7 in livestock manures before application to cropland is critical for reducing the risk of foodborne illness associated with produce. Our objective was to determine the fate of naturally occurring E. coli O157:H7 and other pathogens during minimally managed on-farm bo...

Photocatalytic production of 1O2 and ·OH mediated by silver oxidation during the photoinactivation of Escherichia coli with TiO2

International Nuclear Information System (INIS)

Castro, Camilo A.; Osorio, Paula; Sienkiewicz, Andrzej; Pulgarin, Cesar; Centeno, Aristóbulo; Giraldo, Sonia A.

2012-01-01

Highlights: ► Metallic silver enhances the Ag–TiO 2 photoinactivation of Escherichia coli under Vis irradiation. ► 1 O 2 and ·OH were identified in Vis irradiated Ag–TiO 2 suspensions. ► UV oxidized the Ag metallic species in the material decreasing photoactivity. ► Dark contact of the UV oxidized material with E. coli regenerates the photocatalyst. - Abstract: Ag loaded TiO 2 was applied in the photocatalytic inactivation of Escherichia coli under ultraviolet (UV) and visible (Vis) light irradiations. Ag enhanced the TiO 2 photodisinfecting effect under Vis irradiation promoting the formation of singlet oxygen and hydroxyl radicals as identified by EPR analyses. Ag nanoparticles, determined on TEM analyses, undergo an oxidation process on the TiO 2 's surface under UV or Vis irradiation as observed by XPS. In particular, UV pre-irradiation of the material totally diminished its photodisinfection activity under a subsequent Vis irradiation test. Under UV, photodegradation of dichloroacetic acid (DCA), attributed to photoproduced holes in TiO 2 , was inhibited by the presence of Ag suggesting that oxidation of Ag 0 to Ag + and Ag 2+ is faster than the oxidative path of the TiO 2 's holes on DCA molecules. Furthermore, photoassisted increased of Ag + concentration on TiO 2 's surface enhances the bacteriostatic activity of the material in dark periods. Indeed, this latter dark contact of Ag + –TiO 2 and E. coli seems to induce recovering of the Vis light photoactivity promoted by the surface Ag photoactive species.

British Escherichia coli O157 in Cattle Study (BECS): to determine the prevalence of E. coli O157 in herds with cattle destined for the food chain.

Science.gov (United States)

Henry, M K; Tongue, S C; Evans, J; Webster, C; McKENDRICK, I J; Morgan, M; Willett, A; Reeves, A; Humphry, R W; Gally, D L; Gunn, G J; Chase-Topping, M E

2017-11-01

Escherichia coli O157 are zoonotic bacteria for which cattle are an important reservoir. Prevalence estimates for E. coli O157 in British cattle for human consumption are over 10 years old. A new baseline is needed to inform current human health risk. The British E. coli O157 in Cattle Study (BECS) ran between September 2014 and November 2015 on 270 farms across Scotland and England & Wales. This is the first study to be conducted contemporaneously across Great Britain, thus enabling comparison between Scotland and England & Wales. Herd-level prevalence estimates for E. coli O157 did not differ significantly for Scotland (0·236, 95% CI 0·166-0·325) and England & Wales (0·213, 95% CI 0·156-0·283) (P = 0·65). The majority of isolates were verocytotoxin positive. A higher proportion of samples from Scotland were in the super-shedder category, though there was no difference between the surveys in the likelihood of a positive farm having at least one super-shedder sample. E. coli O157 continues to be common in British beef cattle, reaffirming public health policy that contact with cattle and their environments is a potential infection source.

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...

Aptasensors for rapid detection of Escherichia coli O157:H7 and Salmonella typhimurium

Science.gov (United States)

Wu, Wen-he; Li, Min; Wang, Yue; Ouyang, Hou-xian; Wang, Lin; Li, Ci-xiu; Cao, Yu-chen; Meng, Qing-he; Lu, Jian-xin

2012-11-01

Herein we reported the development of aptamer-based biosensors (aptasensors) based on label-free aptamers and gold nanoparticles (AuNPs) for detection of Escherichia coli ( E. coli) O157:H7 and Salmonella typhimurium. Target bacteria binding aptamers are adsorbed on the surface of unmodified AuNPs to capture target bacteria, and the detection was accomplished by target bacteria-induced aggregation of the aptasensor which is associated as red-to-purple color change upon high-salt conditions. By employing anti- E. coli O157:H7 aptamer and anti- S. typhimurium aptamer, we developed a convenient and rapid approach that could selectively detect bacteria without specialized instrumentation and pretreatment steps such as cell lysis. The aptasensor could detect as low as 105colony-forming units (CFU)/ml target bacteria within 20 min or less and its specificity was 100%. This novel method has a great potential application in rapid detection of bacteria in the near future.

Whole-genome sequence of Escherichia coli serotype O157:H7 strain B6914-ARS

Science.gov (United States)

Escherichia coli serotype O157:H7 strain B6914-MS1 is a Shiga toxin-deficient human fecal isolate obtained by the Centers for Disease Control and Prevention that has been used extensively in applied research studies. Here we report the genome sequence of strain B6914-ARS, a B6914-MS1 clone that has ...

The antimicrobial peptide cathelicidin protects mice from Escherichia coli O157:H7-mediated disease.

Directory of Open Access Journals (Sweden)

Milan Chromek

Full Text Available This study investigated the role of the antimicrobial peptide cathelicidin in Escherichia coli O157:H7 infection and subsequent renal damage. Mouse and human cathelicidin, CRAMP and LL-37, respectively, killed E. coli O157:H7 in vitro. Intestines from healthy wild-type (129/SvJ and cathelicidin-knock-out (Camp(-/- mice were investigated, showing that cathelicidin-deficient mice had a thinner colonic mucus layer compared with wild-type mice. Wild-type (n = 11 and cathelicidin-knock-out (n = 11 mice were inoculated with E. coli O157:H7. Cathelicidin-deficient animals exhibited higher fecal counts of E. coli O157:H7 and bacteria penetrated the mucus forming attaching-and-effacing lesions to a much higher extent than in wild-type animals. Cathelicidin knock-out mice developed symptoms (9/11 as well as anemia, thrombocytopenia and extensive renal tubular damage while all cathelicidin-producing mice remained asymptomatic with normal laboratory findings. When injected with Shiga toxin intraperitoneally, both murine strains developed the same degree of renal tubular damage and clinical disease indicating that differences in sensitivity to infection between the murine strains were related to the initial intestinal response. In conclusion, cathelicidin substantially influenced the antimicrobial barrier in the mouse colon mucosa. Cathelicidin deficiency lead to increased susceptibility to E. coli O157:H7 infection and subsequent renal damage. Administration of cathelicidin or stimulation of endogenous production may prove to be novel treatments for E. coli O157:H7-induced hemolytic uremic syndrome.

The Escherichia coli O157:H7 bovine rumen fluid proteome reflects adaptive bacterial responses

OpenAIRE

Kudva, Indira T; Stanton, Thaddeus B; Lippolis, John D

2014-01-01

Background To obtain insights into Escherichia coli O157:H7 (O157) survival mechanisms in the bovine rumen, we defined the growth characteristics and proteome of O157 cultured in rumen fluid (RF; pH 6.0-7.2 and low volatile fatty acid content) obtained from rumen-fistulated cattle fed low protein content “maintenance diet” under diverse in vitro conditions. Results Bottom-up proteomics (LC-MS/MS) of whole cell-lysates of O157 cultured under anaerobic conditions in filter-sterilized RF (fRF; d...

Occurrence and characterization of Shiga toxin-producing Escherichia coli O157:H7 and other non-sorbitol-fermenting E. coli in cattle and humans in urban areas of Morogoro, Tanzania

DEFF Research Database (Denmark)

Lupindu, Athumani M; Olsen, John Elmerdahl; Ngowi, Helena A

2014-01-01

Escherichia coli strains such as Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli, enterotoxigenic, attaching, and effacing E. coli, and enteroinvasive E. coli cause diarrhea in humans. Although other serotypes exist, the most commonly reported STEC in outbreaks is O157:H7. A cross-...

Distribution of the urease gene cluster among and urease activities of enterohemorrhagic Escherichia coli O157 isolates from humans

NARCIS (Netherlands)

Friedrich, Alexander W; Köck, Robin; Bielaszewska, Martina; Zhang, Wenlan; Karch, Helge; Mathys, Werner

Enterohemorrhagic Escherichia coli (EHEC) O157 strains belong to two closely related major groups, which are differentiated by their sorbitol fermentation phenotypes. Here we studied the conservation of urease genes and their expression in sorbitol-fermenting (SF) and non-SF EHEC O157 isolates. PCR

Primary and secondary cases in Escherichia coli O157 outbreaks: a statistical analysis.

LENUS (Irish Health Repository)

Snedeker, Kate G

2009-01-01

BACKGROUND: Within outbreaks of Escherichia coli O157 (E. coli O157), at least 10-15% of cases are thought to have been acquired by secondary transmission. However, there has been little systematic quantification or characterisation of secondary outbreak cases worldwide. The aim of this study was to characterise secondary outbreak cases, estimate the overall proportion of outbreak cases that were the result of secondary transmission and to analyse the relationships between primary and secondary outbreak cases by mode of transmission, country and median age. METHODS: Published data was obtained from 90 confirmed Escherichia coli O157 outbreaks in Great Britain, Ireland, Scandinavia, Canada, the United States and Japan, and the outbreaks were described in terms of modes of primary and secondary transmission, country, case numbers and median case age. Outbreaks were tested for statistically significant differences in the number of ill, confirmed, primary and secondary cases (analysis of variance and Kruskal-Wallis) and in the rate of secondary cases between these variables (Generalised Linear Models). RESULTS: The outbreaks had a median of 13.5 confirmed cases, and mean proportion of 0.195 secondary cases. There were statistically significant differences in the numbers of ill, confirmed, primary and secondary cases between modes of primary transmission (p < 0.021), and in primary and secondary cases between median age categories (p < 0.039) and modes of secondary transmission (p < 0.001).Secondary case rates differed statistically significantly between modes of secondary and primary transmission and median age categories (all p < 0.001), but not between countries (p = 0.23). Statistically significantly higher rates of secondary transmission were found in outbreaks with a median age <6 years and those with secondary transmission via person to person spread in nurseries. No statistically significant interactions were found between country, mode of transmission and age

Survival of Escherichia coli O157:H7 in needle-tenderized dry cured Westphalian ham.

Science.gov (United States)

Graumann, Gary H; Holley, Richard A

2007-09-15

Westphalian ham is a dry cured, ready-to-eat product that is manufactured without a lethal heat treatment. Hams are preserved by a process that involves curing, fermenting, smoking and drying, which may take 3 months or more to complete. The process can be accelerated by tenderizing the meat with solid needles, to increase the rate of cure-salt diffusion throughout muscle tissues. In this study, intact hams were immersed in a solution containing a five strain cocktail of Escherichia coli O157:H7 at 8 log cfu/mL, to determine whether needle treatment before cure application would internalize organisms from the surface. In two trials, the survival of E. coli O157:H7 on external surfaces and within deep tissues after needle treatment was followed during the ripening of hams. The injured E. coli O157:H7 cells were recovered by plating samples on pre-poured Tryptic Soy Agar plates which were incubated for 3 to 4 h at 35 degrees C, overlaid with Sorbitol MacConkey Agar containing cefixime and tellurite and re-incubated at 35 degrees C for 48 to 72 h. Inoculated-injected hams initially carried E. coli O157:H7 at numbers of 7.3 and 4.6 log cfu/g E. coli O157:H7 on the surface and inside, respectively. After 112 d of ripening, which included 79 d of drying, no E. coli O157:H7 were detected at the surface of hams following enrichment, whereas in deep tissue the organism was recovered at numbers of 3.1 log cfu/g. The Westphalian ham ripening procedure evidently was not adequate to eliminate E. coli O157:H7 internalized by needle tenderization.

Mathematical modeling and numerical analysis of the growth of Non-O157 shiga toxin-producing Escherichia coli in spinach leaves

Science.gov (United States)

This study was conducted to investigate the growth of non-O157 Shiga toxin-producing Escherichia coli (STEC) in spinach leaves and to develop kinetic models to describe the bacterial growth. Six serogroups of non-O157 STEC, including O26, O45, O103, O111, O121, and O145, were used in the growth stu...

Salt at concentrations relevant to meat processing enhances Shiga toxin 2 production in Escherichia coli O157:H7.

Science.gov (United States)

Harris, Shaun M; Yue, Wan-Fu; Olsen, Sarena A; Hu, Jia; Means, Warrie J; McCormick, Richard J; Du, Min; Zhu, Mei-Jun

2012-10-15

Escherichia coli (E. coli) O157:H7 remains a major food safety concern associated with meat, especially beef products. Shiga toxins (Stx) are key virulence factors produced by E. coli O157:H7 that are responsible for hemorrhagic colitis and Hemolytic Uremic Syndrome. Stx are heat stable and can be absorbed after oral ingestion. Despite the extensive study of E. coli O157:H7 survival during meat processing, little attention is paid to the production of Stx during meat processing. The objective of this study was to elucidate the effect of salt, an essential additive to processed meat, at concentrations relevant to meat processing (0%, 1%, 2%, 3%, W/V) on Stx2 production and Stx2 prophage induction by E. coli O157:H7 strains. For both E. coli O157:H7 86-24 and EDL933 strains, including 2% salt in LB broth decreased (Pmeat processing enhances Stx production, a process linked to bacterial stress response and lambdoid prophage induction. Published by Elsevier B.V.

Survival of Escherichia coli O157:H7 in ground beef jerky assessed on two plating media.

Science.gov (United States)

Harrison, J A; Harrison, M A; Rose, R A

1998-01-01

Recent outbreaks of food-borne illness due to Salmonella spp. in beef jerky and Escherichia coli O157:H7 in venison jerky, coupled with the fact that a variety of preparation methods and dying procedures abound, raise concern over the safety of processed meat products made in the home. The potential of injured bacterial cells to regain the ability to cause illness is a particular threat with pathogens such as E. coli O157:H7, which is believed to have a low infectious dose. This study examined the efficacy of various methods of jerky preparation in reducing populations of E, coli O157:H7 in ground beef jerky and compared the recovery rate of E. coli O157:H7 on two selective plating media, modified sorbitol MacConkey agar (MSMA) and modified eosin methylene blue agar (MEMB). Populations of E. coli O157:H7 in both heated and unheated samples exhibited a greater decline during drying when a nitrite and salt cure mix was added during jerky preparation. When recovery of E. coli O157:H7 on MSMA and MEMB was compared, a trend toward slightly higher recovery rates with MEMB was observed. On the basis of these results, MEMB is a suitable alternative to MSMA for the recovery of E. coli O157:H7 from heated and dried meat samples similar to beef jerky.

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.

Detection of Escherichia coli O157:H7 in the beef marketed in Malaysia.

Science.gov (United States)

Radu, S; Abdul Mutalib, S; Rusul, G; Ahmad, Z; Morigaki, T; Asai, N; Kim, Y B; Okuda, J; Nishibuchi, M

1998-03-01

Twelve strains of Escherichia coli O157:H7 were isolated from 9 of 25 beef samples purchased from retail stores in Malaysia. These strains produced Shiga toxin 2 with or without Shiga toxin 1 and had the eae gene and a 60-MDa plasmid. The antibiograms and the profiles of the arbitrarily primed PCR of the strains were diverse, suggesting that the strains may have originated from diverse sources.

Effects of water chemistry on the dissolution of ZnO nanoparticles and their toxicity to Escherichia coli

International Nuclear Information System (INIS)

Li Mei; Lin Daohui; Zhu Lizhong

2013-01-01

The dissolution of ZnO nanoparticles (nano-ZnO) plays an important role in the toxicity of nano-ZnO to the aquatic organisms. The effects of water chemistry such as pH, ionic components, and dissolved organic matter (DOM) on the dissolution of nano-ZnO and its toxicity to Escherichia coli (E. coli) were investigated in synthetic and natural water samples. The results showed that the toxicity of nano-ZnO to E. coli depended on not only free Zn 2+ but also the coexisting cations which could reduce the toxicity of Zn 2+ . Increasing solution pH, HPO 4 2− , and DOM reduced the concentration of free Zn 2+ released from nano-ZnO, and thus lowered the toxicity of nano-ZnO. In addition, both Ca 2+ and Mg 2+ dramatically reduced the toxicity of Zn 2+ to E. coli. These results highlight the importance of water chemistry on the toxicity evaluation of nano-ZnO in natural waters. - Highlights: ► The effects of water chemistry on the toxicity of nano-ZnO were investigated. ► Increasing solution pH, HPO 4 2− , and DOM reduced nano-ZnO toxicity to E. coli. ► Ca 2+ and Mg 2+ could dramatically reduce the toxicity of nano-ZnO to E. coli. ► Free Zn 2+ ions and water hardness together controlled nano-ZnO toxicity in waters. - The toxicity of nano-ZnO to E. coli depended on not only free Zn 2+ but also Ca 2+ and Mg 2+ which could reduce the toxicity of Zn 2+ .

Genome sequences of thirty Escherichia coli O157:H7 isolates recovered from a single dairy farm and its associated off-site heifer raising facility

Science.gov (United States)

Cattle are the primary reservoir of Escherichia coli O157:H7, the most frequently isolated serotype of enterohemorrhagic E. coli infections among humans in North America. To evaluate the diversity of E. coli O157:H7 isolates within a single dairy herd the genomes of 30 isolates collected over a 7-ye...

Screening of the novel colicinogenic gram-negative rods against pathogenic Escherichia coli O157:H7

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H Mushtaq

2015-01-01

Full Text Available Purpose: Escherichia coli (E. coli O157:H7 is gram-negative enteric pathogen producing different types of Shiga toxin. This bacterium is the most corporate cause of haemorrhagic colitis in human. Administration of antibiotics (particularly sulfa drugs against this pathogen is a debatable topic as this may increase the risk of uremic syndrome; especially in children and aged people. Around the world, microbiologists are in search of alternative therapeutic methods specially probiotics against this pathogen. In the present study, we have focused on the investigation of alternate bio-therapeutics (probiotics for the treatment of patients infected with E. coli O157:H7. This study is based on the identification of colicin-producing gram-negative bacteria (particularly enterobacteriaceae which can competently exclude E. coli O157:H7 from the gut of the infected individual. Materials and Methods: Hundred samples from human, animal faeces and septic tank water were analysed for nonpathogenic gram-negative rods (GNRs. Results: Out of these samples, 175 isolates of GNRs were checked for their activity against E. coli O157:H7. Only 47 isolates inhibited the growth of E. coli O157:H7, among which majority were identified as E. coli. These E. coli strains were found to be the efficient producers of colicin. Some of the closely related species i. e., Citrobacter sp, Pantoea sp. and Kluyvera sp. also showed considerable colicinogenic activity. Moreover, colicinogenic species were found to be nonhaemolytic, tolerant to acidic environment (pH 3 and sensitive to commonly used antibiotics. Conclusion: Nonhaemolytic, acid tolerant and sensitive to antibiotics suggests the possible use of these circulating endothelial cells (CEC as inexpensive and inoffensive therapeutic agent (probiotics in E. coli O157:H7 infections.

Escherichia Coli

Science.gov (United States)

Goodsell, David S.

2009-01-01

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

Proliferation of Escherichia coli O157:H7 in Soil-Substitute and Hydroponic Microgreen Production Systems.

Science.gov (United States)

Xiao, Zhenlei; Bauchan, Gary; Nichols-Russell, Lydia; Luo, Yaguang; Wang, Qin; Nou, Xiangwu

2015-10-01

Radish (Raphanus sativus var. longipinnatus) microgreens were produced from seeds inoculated with Escherichia coli O157:H7 by using peat moss-based soil-substitute and hydroponic production systems. E. coli populations on the edible and inedible parts of harvested microgreen plants (7 days postseeding) and in growth medium were examined. E. coli O157:H7 was shown to survive and proliferate significantly during microgreen growth in both production systems, with a higher level in the hydroponic production system. At the initial seed inoculation level of 3.7 log CFU/g, E. coli O157:H7 populations on the edible part of microgreen plants reached 2.3 and 2.1 log CFU/g (overhead irrigation and bottom irrigation, respectively) for microgreens from the soil-substitute production system and reached 5.7 log CFU/g for those hydroponically grown. At a higher initial inoculation of 5.6 log CFU/g seeds, the corresponding E. coli O157:H7 populations on the edible parts of microgreens grown in these production systems were 3.4, 3.6, and 5.3 log CFU/g, respectively. Examination of the spatial distribution of bacterial cells on different parts of microgreen plants showed that contaminated seeds led to systematic contamination of whole plants, including both edible and inedible parts, and seed coats remained the focal point of E. coli O157:H7 survival and growth throughout the period of microgreen production.

DETERMINAÇÃO DO VALOR D10 PARA ESCHERICHIA COLI EM POLPA DE JUÇARA IRRADIADA

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Paula Porrelli Moreira da SILVA

2011-04-01

Full Text Available A aplicação de tratamentos não térmicos tem se mostrado efi ciente na inibição de bactérias como Escherichia coli. Sua presença em alimentos processados é considerada uma indicação útil de contaminação pós sanitização ou pós processo (principalmente no caso da pasteurização, evidenciando práticas de higiene e sanitização inadequados para o processamento de alimentos. A irradiaçãoéum métodoefi cientede conservação de alimentos, por reduzir o número de micro-organismos patogênicos e deteriorantes, sem que as características sensoriais e nutricionais do alimento sejam alteradas signifi cativamente. A juçara (Euterpe edulis é palmeira nativa da Mata Atlântica, que além do palmito, produz frutos comestí- veis similares ao açaí, possuindo interesse econômico. Os objetivos desta pesquisa foram determinar o valor D10 de Escherichia coli inoculada em polpa de juçara (E. edulis irradiada, recomendando-se uma dose de radiação para ser aplicada a esse alimento a fi m de torná-lo seguro frente a este micro-organismo. O valor D10 foi calculado a partir da curva de sobreviventes dessa bactéria em polpa de ju- çara, após ter sido exposta às doses de 0kGy (controle; 0,5kGy; 1,0kGy; 1,5kGy e 2,0kGy. O valor D10 obtido foi 0,404kGy, sendo que a dose de radiação recomendada para reduzir sete ciclos logarítmicos de E. coli, a fi m de garantir a segurança higiênico-sanitária do produto, foi de 2,83kGy.

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

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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.

Sources of Escherichia coli O157 and experiences over the past 15 years in Sheffield, UK.

Science.gov (United States)

Chapman, P A

2000-01-01

In the first documented outbreak of HC caused by Escherichia coli O157, which occurred in the North-west USA in 1982, there was a strong association between infection and prior consumption of ground beef from a chain of fast food restaurants. Foods of bovine origin, including beef, milk and dairy products, have since been implicated in many outbreaks of infection world-wide. Investigations during the course of outbreaks, or at random, have shown that cattle are a major reservoir of E. coli O157. E. coli O157 was isolated from cattle at slaughter in Sheffield in 1987, this being the first isolation from cattle in the UK. Following a cluster of cases in May/June 1992, an abattoir study showed the organism to be present in 4% of cattle at slaughter and on up to a third of carcasses from rectal swab-positive animals. E. coli O157 was isolated from a food source (unpasteurized milk), for the first time in the UK, in Sheffield in May 1993. During surveillance in 1995-6, E. coli O157 was isolated from 15.7% of cattle, with a monthly prevalence which varied from 5 to 37%. E. coli O157 was also isolated from 2.2% of sheep. During surveillance in 1996, E. coli O157 was isolated from 5.9% of samples of lamb products and from 1.5% of samples of beef products, despite the prevalence in cattle being much higher than in sheep. Work is in progress to try to explain this higher prevalence in lamb products. During 1997 in Sheffield, the only cases of E. coli O157 for which a confirmed source was established were associated with direct animal contact on farm visits. During on-farm investigations of these cases, E. coli O157 was isolated from faecal samples from adult cattle, calves, three different breeds of sheep, two different breeds of pigs, goats and a pony.

Lethality prediction for Escherichia coli 0157:H7 and Uropathogenic E. coli in ground chicken treated with high pressure processing and trans-cinnamaldehyde

Science.gov (United States)

Pathogenic Escherichia coli, intestinal (O157:H7) as well as extraintestinal types (Uropathogenic E. coli (UPEC)) are commonly found in many foods including chicken meat. In this study we compared the resistance of E. coli O157:H7 to UPEC in chicken meat under the stresses of high hydrostatic pressu...

Use of Bacteriophages to Control Escherichia coli O157:H7 in Domestic Ruminants, Meat Products, and Fruits and Vegetables.

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Wang, Lili; Qu, Kunli; Li, Xiaoyu; Cao, Zhenhui; Wang, Xitao; Li, Zhen; Song, Yaxiong; Xu, Yongping

2017-09-01

Escherichia coli O157:H7 is an important foodborne pathogen that causes severe bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Ruminant manure is a primary source of E. coli O157:H7 contaminating the environment and food sources. Therefore, effective interventions targeted at reducing the prevalence of fecal excretion of E. coli O157:H7 by cattle and sheep and the elimination of E. coli O157:H7 contamination of meat products as well as fruits and vegetables are required. Bacteriophages offer the prospect of sustainable alternative approaches against bacterial pathogens with the flexibility of being applied therapeutically or for biological control purposes. This article reviews the use of phages administered orally or rectally to ruminants and by spraying or immersion of fruits and vegetables as an antimicrobial strategy for controlling E. coli O157:H7. The few reports available demonstrate the potential of phage therapy to reduce E. coli O157:H7 carriage in cattle and sheep, and preparation of commercial phage products was recently launched into commercial markets. However, a better ecological understanding of the phage E. coli O157:H7 will improve antimicrobial effectiveness of phages for elimination of E. coli O157:H7 in vivo.

Seroprevalence of Escherichia coli in traditional cheeses manufactured in Maragheh rural

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S Mahdavi

2014-11-01

Full Text Available Coliforms and Escherichia coli are major microbial indicators in the accessing the quality of foodstuffs. The presence of these bacteria in foods is considered as an indication of fecal contamination. E. coli O157:H7 is the most pathogenic strain that is transmitted to human through animal-foods. This study was performed on 100 traditional cheese samples manufactured in Maragheh rural to determine the seroprevalence of E. coli. The samples were analyzed with standard microbiological methods followed by biochemical confirmatory tests. Afterwards, the isolates were assayed for the detection of O-serotypes using direct agglutination method. Among the 100 cheese samples, E. coli O157serotypewas not detected in any sample. However, other E. coli serotypes including 32 isolates of non-O157 serotypes were detected. Among the isolates, enteropathogenic, enterotoxigenic and enterohaemorhhagic serogruops was also detected.

The iron uptake mechanisms of enteroinvasive Escherichia coli Mecanismos de captação de ferro de Escherichia coli enteroinvasora

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Agda Andrade

2000-09-01

Full Text Available Enteroinvasive Escherichia coli strains (EIEC of different serotypes isolated from patients with acute diarrhea were examined for the ability to produce siderophores and iron-regulated outer membrane proteins (IROMP. For iron starvation cultures were grown at 37°C in LB supplied with 200 muM of a-alpha’dypirydil. All strains produced enterobactin and twelve (40% produced aerobactin. The strains showed IROMP varying from 67-82 kDa. Proteins were either induced or stimulated by the iron starvation. Differences were observed in the electrophoretic profile among the serotypes, originating 5 electrophoretic profiles. All serotypes expressed proteins of 82 kDa (FepA and 76 kDa (IutA (except serotype O28ac:H- that did not produce the 76 kDa protein. Several strains (O29:H-, O144:H-, O152:H-, and O167:H- expressed IutA in the outer membrane, in the absence of aerobactin production. Additionally to well characterized proteins (FepA and IutA, we found two IROMP of unknown function in some serotypes: a 71 kDa protein was detected in three profiles and a 67 kDa protein was present in serotype O152:H-. Moreover, two bands (39 and 43 kDa which were not iron-regulated bound specifically to human lactoferrin.Cepas de Escherichia coli enteroinvasora de diferentes sorotipos isoladas de pacientes com diarréia aguda foram examinadas quanto a capacidade de produzir sideróforos e proteínas de membrana externa reguladas pelo ferro (IROMP. O crescimento bacteriano em meio com deficiência em Fe foi obtido em caldo Lúria acrescido de 200 mM de alfa-a’dipiridil. Todas as cepas produziram enterobactina e 40% produziram aerobactina. As cepas produziram IROMPs com MM variando de 82-67 kDa. As proteínas foram induzidas ou estimuladas pela deficiência de ferro. Diferenças foram observadas no perfil eletroforético entre os sorotipos, originando 5 perfis eletroforéticos. Todos os sorotipos, com exceção do sorotipo O28ac:H- (onde a proteína de 76 kDa não foi

Virulence factors, serogroups and antimicrobial resistance properties of Escherichia coli strains in fermented dairy products.

Science.gov (United States)

Dehkordi, Farhad Safarpoor; Yazdani, Farshad; Mozafari, Jalal; Valizadeh, Yousef

2014-04-07

From a clinical perspective, it is essential to know the microbial safety of fermented dairy products. Doogh and kashk are fermented dairies. These products are used by millions of people but their microbial qualities are unknown. Shiga toxin producing Escherichia coli (STEC) is one of the most commonly detected pathogens in the cases of food poisoning and food-borne illnesses. The present investigation was carried out in order to study the molecular characterization and antimicrobial resistance properties of STEC strains isolated from fermented dairy products. Six hundred fermented dairy samples were collected and immediately transferred to the laboratory. All samples were cultured immediately and those that were E. coli-positive were analyzed for the presence of O157 , O26, O103, O111, O145, O45, O91, O113, O121 and O128 STEC serogroups, tetA, tetB, blaSHV, CITM, cmlA, cat1, aadA1, dfrA1, qnr, aac (3)-IV, sul1 and ereA antibiotic resistance genes and stx1, stx2, eaeA, ehly, cnf1, cnf2, iutA, cdtB, papA, traT, sfaS and fyuA virulence factors using PCR. Antimicrobial susceptibility testing was performed also using disk diffusion methodology with Mueller-Hinton agar. Fifty out of 600 (8.33%) dairy samples harbored E. coli. In addition, yoghurt was the most commonly contaminated dairy. O157 (26%) and O26 (12%) were the most commonly detected serogroups. A significant difference was found between the frequency of Attaching and Effacing E. coli and Enterohaemorrhagic E. coli (P Fermented dairy products can easily become contaminated by antibiotic resistant STEC strains. Our findings should raise awareness about antibiotic resistance in Iran. Clinicians should exercise caution when prescribing antibiotics, especially in veterinary treatments.

Gene encoding virulence markers among Escherichia coli isolates ...

African Journals Online (AJOL)

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

Utilização da vacina Escherichia coli J5 na imunização de vacas leiteiras contra mastites causadas por E. coli

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Lívio R. Molina

2013-03-01

Full Text Available Avaliou-se a utilização da vacina Escherichia coli J5, na imunização de vacas leiteiras, para prevenção e controle da mastite causada por E. coli através da análise da prevalência das infecções intramamárias (IMM no pós-parto, ocorrência e intensidade dos casos clínicos de mastite nos primeiros 100 dias de lactação, influência na contagem de células somáticas (CCS e produção de leite. O grupo experimental foi composto de 187 animais, divididos em 2 grupos, vacas vacinadas e não vacinadas. As imunizações ocorreram 60 dias antes do parto, 30 dias antes do parto e na primeira semana pós-parto. No dia da secagem e sete dias após o parto foram coletadas amostras para diagnóstico microbiológico dos patógenos causadores de mastite. A ocorrência de casos clínicos foi verificada pelo teste da caneca durante as ordenhas sendo registrados os dados relacionados à intensidade. Amostras foram coletadas mensalmente, a partir do décimo dia de lactação, para avaliação da CCS. A produção de leite foi registrada mensalmente nos primeiros 100 dias de lactação. Verificou-se no grupo vacinado, redução na prevalência de E. coli no pós-parto, na ocorrência de casos clínicos por E.coli nos primeiros 100 dias de lactação bem como na intensidade destes casos clínicos. Não foram observadas diferenças estatísticas significativas na CCS, entretanto vacas vacinadas apresentaram maior produção de leite, comparadas às vacas não vacinadas. A vacinação com E. coli J5 foi eficaz em reduzir a prevalência de infecções intramamárias (IMM ao parto, ocorrência e intensidade dos casos clínicos e aumento na produção de leite nos primeiros 100 dias de lactação.

Spread of avian pathogenic Escherichia coli ST117 O78:H4 in Nordic broiler production

DEFF Research Database (Denmark)

Ronco, Troels; Stegger, Marc; Olsen, Rikke Heidemann

2017-01-01

Escherichia coli infections known as colibacillosis constitute a considerable challenge to poultry farmers worldwide, in terms of decreased animal welfare and production economy. Colibacillosis is caused by avian pathogenic E. coli (APEC). APEC strains are extraintestinal pathogenic E. coli...... of isolates were collected from poultry with colibacillosis on Nordic farms. Subsequently, comparative genomic analyses were carried out. This included in silico typing (sero- and multi-locus sequence typing), identification of virulence and resistance genes and phylogenetic analyses based on single...... diseased broilers and breeders. The data indicate that the closely related ST117 O78:H4 strains have been transferred vertically through the broiler breeding pyramid into distantly located farms across the Nordic countries....

Crystallization and preliminary crystallographic studies of the YafN–YafO complex from Escherichia coli

International Nuclear Information System (INIS)

Zhang, Fan; Xing, Li; Teng, Maikun; Li, Xu

2012-01-01

The ribosome-dependent mRNA interferase YafO from Escherichia coli belongs to a type II toxin–antitoxin (TA) system and its cognate antitoxin YafN neutralizes cell toxicity by forming a stable YafN–YafO complex. Here, the YafN–YafO complex has been expressed and crystallized. The ribosome-dependent mRNA interferase YafO from Escherichia coli belongs to a type II toxin–antitoxin (TA) system and its cognate antitoxin YafN neutralizes cell toxicity by forming a stable YafN–YafO complex. The YafN–YafO TA system is upregulated by the SOS response (a global response to DNA damage in which the cell cycle is arrested and mutagenesis is induced) and may then inhibit protein synthesis by endoribonuclease activity of YafO with the 50S ribosome subunit. Structural information on the YafN–YafO complex and related complexes would be helpful in order to understand the structural basis of the mechanism of mRNA recognition and cleavage, and the assembly of these complexes. Here, the YafN–YafO complex was expressed and crystallized. Crystals grown by the hanging-drop vapour-diffusion method diffracted to 3.50 Å resolution and belonged to the hexagonal space group P622, with unit-cell parameters a = 86.14, b = 86.14, c = 173.11 Å, α = β = 90, γ = 120°. Both Matthews coefficient analysis and the self-rotation function suggested the presence of one molecule per asymmetric unit in the crystal, with a solvent content of 65.69% (V M = 3.58 Å 3 Da −1 )

Complete Genome Sequence of an Escherichia coli O121:H19 Strain from an Outbreak in Canada Associated with Flour

Science.gov (United States)

Robertson, James; Lin, Janet; Levett, Paul N.; Nadon, Celine; Nash, John

2018-01-01

ABSTRACT Here, we present the first complete genome sequence of an Escherichia coli non-O157 Shiga-toxin producing isolate, 16-9255, from serotype O121:H19. This strain is notable as a clinical case recovered from a recent Canadian flour-associated outbreak event. PMID:29371368

Detecção de fatores de virulência de Escherichia coli e análise de Salmonella spp. em psitacídeos

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Isadora M. de O. Corrêa

2013-02-01

Full Text Available A flora entérica dos psitacídeos é composta principalmente por bactérias Gram positivas. Bactérias Gram negativas, como Escherichia coli e Salmonella spp., apresentam elevado potencial patogênico, sendo consideradas indicativo de problemas de manejo, que poderão culminar em manifestação de doenças em decorrência de fatores estressantes, dietas deficientes e superlotação, combinados com alta carga bacteriana no ambiente. O objetivo deste trabalho foi avaliar a presença de Salmonella spp., Escherichia coli e os fatores de virulência dos genes iss e iutA dos isolados de E. coli. Analisou-se um total de 44 amostras provenientes de psitacídeos criados em cativeiro, sendo estas 15 fragmentos de órgãos de aves submetidas a exame de necropsia e também 29 amostras de swabs de cloaca e inglúvio de papagaios-charão (Amazona pretrei criados em cativeiro. Nenhuma amostra foi positiva para Salmonella spp. Nas amostras de E. coli detectou-se ambos os fatores de virulência pesquisados.

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.

DNA fingerprinting of Shiga-toxin producing Escherichia coli O157 based on Multiple-Locus Variable-Number Tandem-Repeats Analysis (MLVA

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Vardund Traute

2003-12-01

Full Text Available Abstract Background The ability to react early to possible outbreaks of Escherichia coli O157:H7 and to trace possible sources relies on the availability of highly discriminatory and reliable techniques. The development of methods that are fast and has the potential for complete automation is needed for this important pathogen. Methods In all 73 isolates of shiga-toxin producing E. coli O157 (STEC were used in this study. The two available fully sequenced STEC genomes were scanned for tandem repeated stretches of DNA, which were evaluated as polymorphic markers for isolate identification. Results The 73 E. coli isolates displayed 47 distinct patterns and the MLVA assay was capable of high discrimination between the E. coli O157 strains. The assay was fast and all the steps can be automated. Conclusion The findings demonstrate a novel high discriminatory molecular typing method for the important pathogen E. coli O157 that is fast, robust and offers many advantages compared to current methods.

Viabilidad de Escherichia coli en presencia de diferentes contaminantes

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Antonio Rivera T

2006-04-01

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

Simulating Escherichia coli O157:H7 transmission to assess effectiveness of interventions in Dutch dairy-beef slaughterhouses

NARCIS (Netherlands)

Vosough Ahmadi, B.; Velthuis, A.G.J.; Hogeveen, H.; Huirne, R.B.M.

2006-01-01

Beef contamination with Escherichia coli O157:H7 (VTEC) is an important food-safety issue. To investigate the effectiveness of interventions against VTEC in Dutch beef industrial slaughterhouses that slaughter 500 dairy cattle per day, a Monte Carlo simulation model was built. We examined seven

Changing plasmid types responsible for extended spectrum cephalosporin resistance in Escherichia coli O157:H7 in the United States, 1996–2009

OpenAIRE

Folster, J. P.; Pecic, G.; Stroika, S.; Rickert, R.; Whichard, J.

2014-01-01

Escherichia coli O157 is a major cause of foodborne illness. Plasmids are genetic elements that mobilize antimicrobial resistance determinants including blaCMY β-lactamases that confer resistance to extended-spectrum cephalosporins (ESC). ESCs are important for treating a variety of infections. IncA/C plasmids are found among diverse sources, including cattle, the principal source of E. coli O157 infections in humans. IncI1 plasmids are common among E. coli and Salmonella from poultry and oth...

Development of an allele-specific PCR assay for simultaneous sero-typing of avian pathogenic Escherichia coli predominant O1, O2, O18 and O78 strains.

Science.gov (United States)

Wang, Shaohui; Meng, Qingmei; Dai, Jianjun; Han, Xiangan; Han, Yue; Ding, Chan; Liu, Haiwen; Yu, Shengqing

2014-01-01

Systemic infections by avian pathogenic Escherichia coli (APEC) are economically devastating to poultry industries worldwide. E. coli strains belonging to serotypes O1, O2, O18 and O78 are preferentially associated with avian colibacillosis. The rfb gene cluster controlling O antigen synthesis is usually various among different E. coli serotypes. In present study, the rfb gene clusters of E. coli serotypes O1, O2, O18 and O78 were characterized and compared. Based on the serotype-specific genes in rfb gene cluster, an allele-specific polymerase chain reaction (PCR) assay was developed. This PCR assay was highly specific and reliable for sero-typing of APEC O1, O2, O18 and O78 strains. The sensitivity of the assay was determined as 10 pg DNA or 10 colony forming units (CFUs) bacteria for serotypes O2 and O18 strains, and 500 pg DNA or 1,000 CFUs bacteria for serotypes O1 and O78 strains. Using this PCR system, APEC isolates and the infected tissue samples were categorized successfully. Furthermore, it was able to differentiate the serotypes for the samples with multi-agglutination in the traditional serum agglutination assay. Therefore, the allele-specific PCR is more simple, rapid and accurate assay for APEC diagnosis, epidemiologic study and vaccine development.

Development of an allele-specific PCR assay for simultaneous sero-typing of avian pathogenic Escherichia coli predominant O1, O2, O18 and O78 strains.

Directory of Open Access Journals (Sweden)

Shaohui Wang

Full Text Available Systemic infections by avian pathogenic Escherichia coli (APEC are economically devastating to poultry industries worldwide. E. coli strains belonging to serotypes O1, O2, O18 and O78 are preferentially associated with avian colibacillosis. The rfb gene cluster controlling O antigen synthesis is usually various among different E. coli serotypes. In present study, the rfb gene clusters of E. coli serotypes O1, O2, O18 and O78 were characterized and compared. Based on the serotype-specific genes in rfb gene cluster, an allele-specific polymerase chain reaction (PCR assay was developed. This PCR assay was highly specific and reliable for sero-typing of APEC O1, O2, O18 and O78 strains. The sensitivity of the assay was determined as 10 pg DNA or 10 colony forming units (CFUs bacteria for serotypes O2 and O18 strains, and 500 pg DNA or 1,000 CFUs bacteria for serotypes O1 and O78 strains. Using this PCR system, APEC isolates and the infected tissue samples were categorized successfully. Furthermore, it was able to differentiate the serotypes for the samples with multi-agglutination in the traditional serum agglutination assay. Therefore, the allele-specific PCR is more simple, rapid and accurate assay for APEC diagnosis, epidemiologic study and vaccine development.

Impact of persistent and nonpersistent generic Escherichia coli and Salmonella sp. recovered from a beef packing plant on biofilm formation by E. coli O157.

Science.gov (United States)

Visvalingam, J; Ells, T C; Yang, X

2017-12-01

To examine the influence of meat plant Escherichia coli and Salmonella sp. isolates on E. coli O157 biofilm formation. Biofilm formation was quantified by crystal violet staining (A 570 nm ) and viable cell numbers for up to 6 days at 15°C. All five persistent E. coli genotypes formed strong biofilms when cultured alone or co-cultured with E. coli O157, with A 570 nm values reaching ≥4·8 at day 4, while only two of five nonpersistent genotypes formed such biofilms. For E. coli O157:H7 co-culture biofilms with E. coli genotypes 136 and 533, its numbers were ≥1·5 and ≥1 log CFU per peg lower than those observed for its mono-culture biofilm at days 2 and 4, respectively. The number of E. coli O157:NM in similar co-culture biofilms was 1 log CFU per peg lower than in its mono-culture biofilm at day 4 and 6, respectively. Salmonella sp. lowered the number of E. coli O157:NM by 0·5 log unit, once, at day 6. Generic E. coli may outcompete E. coli O157 strains while establishing biofilms. Findings advance knowledge regarding inter-strain competition for a similar ecological niche and may aid development of biocontrol strategies for E. coli O157 in food processing environments. © 2017 Her Majesty the Queen in Right of Canada. Journal of Applied Microbiology © 2017 The Society for Applied Microbiology Reproduced with the permission of the Minister of the Department of Agriculture and Agri-Food Canada.

Synergistic effect of enterocin AS-48 in combination with outer membrane permeabilizing treatments against Escherichia coli O157:H7.

Science.gov (United States)

Ananou, S; Gálvez, A; Martínez-Bueno, M; Maqueda, M; Valdivia, E

2005-01-01

To determine the effects of outer membrane (OM) permeabilizing agents on the antimicrobial activity of enterocin AS-48 against Escherichia coli O157:H7 CECT 4783 strain in buffer and apple juice. We determined the influence of pH, EDTA, sodium tripolyphosphate (STPP) and heat on E. coli O157:H7 CECT 4783 sensitivity to enterocin AS-48 in buffer and in apple juice. Enterocin AS-48 was not active against intact cells of E. coli O157:H7 CECT 4783 at neutral pH. However, cells sublethally injured by OM permeabilizing agents (EDTA, STPP, pH 5, pH 8.6 and heat) became sensitive to AS-48, decreasing the amount of bacteriocin required for inhibition of E. coli O157:H7 CECT 4783. The results presented indicate that enterocin AS-48 could potentially be applied with a considerably wider range of protective agents, such as OM permeabilizing agents, with increased efficacy in inhibiting E. coli O157:H7. Results from this study support the potential use of enterocin AS-48 to control E. coli O157:H7 in combination with other hurdles.

Thermal inactivation of Escherichia coli 0157:H7 (ECOH) and non-0157 Shiga toxin-producing E.coli (STEC)in mechanically tenderized veal

Science.gov (United States)

We quantified thermal destruction of Shiga toxin-producing Escherichia coli O157:H7 (ECOH) and Shiga toxin-producing non-O157 E. coli (STEC) cells within mechanically tenderized veal cutlets following cooking on an electric skillet. For each of five trials, flattened veal cutlets (ca. 71.6 g; ca. 1/...

Behavior of pulsed electric field injured Escherichia coli O157:H7 cells in apple juice amended with pyruvate and catalase

Science.gov (United States)

Pulse Electric Field (PEF) treatment has been used to inactivate bacteria in liquid foods. However, information on the behavior of PEF injured Escherichia coli bacteria in media during storage at 5 and 23C are limited. In this study, we investigated the fate of E. coli O157:H7 cells at 6.8 log CFU/m...

Pathogenic Escherichia coli and food handlers in luxury hotels in Nairobi, Kenya.

Science.gov (United States)

Onyango, Abel O; Kenya, Eucharia U; Mbithi, John J N; Ng'ayo, Musa O

2009-11-01

The epidemiology and virulence properties of pathogenic Escherichia coli among food handlers in tourist destination hotels in Kenya are largely uncharacterized. This cross-sectional study among consenting 885 food handlers working in nine luxurious tourist hotels in Nairobi, Kenya determined the epidemiology, virulence properties, antibiotics susceptibility profiles and conjugation abilities of pathogenic Escherichia coli. Pathogenic Escherichia coli was detected among 39 (4.4%) subjects, including 1.8% enteroaggregative Escherichia coli (EAEC) harboring aggR genes, 1.2% enterotoxigenic Escherichia coli (ETEC) expressing both LT and STp toxins, 1.1% enteropathogenic Escherichia coli (EPEC) and 0.2% Shiga-like Escherichia coli (EHEC) both harboring eaeA and stx2 genes respectively. All the pathotypes had increased surface hydrophobicity. Using multivariate analyses, food handlers with loose stools were more likely to be infected with pathogenic Escherichia coli. Majority 53.8% of the pathotypes were resistant to tetracycline with 40.2% being multi-drug resistant. About 85.7% pathotypes trans-conjugated with Escherichia coli K12 F(-) NA(r) LA. The carriage of multi-drug resistant, toxin expressing pathogenic Escherichia coli by this population is of public health concern because exposure to low doses can result in infection. Screening food handlers and implementing public awareness programs is recommended as an intervention to control transmission of enteric pathogens.

Growth kinetics of Escherichia coli O157:H7 on the epicarp of fresh vegetables and fruits

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Mariel Gullian-Klanian

Full Text Available ABSTRACT Despite the increasing reports on the incidence of fresh vegetables and fruits as a possible vehicle for human pathogens, there is currently limited knowledge on the growth potential of Escherichia coli O157:H7 on different plant substrates. This study analyzed the selective adhesion and growth of E. coli O157:H7 on chili habanero (Capsicum chinense L., cucumber (Cucumis sativus, radish (Raphanus sativus, tomato (Lycopersicon esculentum, beet (Beta vulgaris subsp. vulgaris, and onion (Allium cepa L. under laboratory conditions. The Gompertz parameters were used to determine the growth kinetics. Scanning electron microscopy was used to visualize the adhesion of E. coli O157:H7 on the epicarp of the samples. Predictive models were constructed to compare the growth of E. coli O157:H7 on the samples with different intrinsic factors and to demonstrate the low selectivity of the pathogen. No significant difference was observed in the lag-phase duration (LPD, generation time (GT, and exponential growth rate (EGR of the pathogen adhered to the samples. The interaction between the microorganism and the substrate was less supportive to the growth of E. coli O157:H7 for onion, whereas for tomato and cucumber, the time for the microorganism to attain the maximum growth rate (M was significantly longer than that recorded for other samples.

Efficacy of (+-Lariciresinol to Control Bacterial Growth of Staphylococcus aureus and Escherichia coli O157:H7

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Vivek K. Bajpai

2017-05-01

Full Text Available This study was undertaken to assess the antibacterial potential of a polyphenolic compound (+-lariciresinol isolated from Rubia philippinensis against selected foodborne pathogens Staphylococcus aureus KCTC1621 and Escherichia coli O157:H7. (+-Lariciresinol at the tested concentrations (250 μg/disk evoked a significant antibacterial effect as a diameter of inhibition zones (12.1–14.9 mm with minimum inhibitory concentration (MIC, and minimum bactericidal concentration values of 125–250 and 125–250 μg/mL, respectively. Furthermore, (+-lariciresinol at MIC showed reduction in bacterial cell viabilities, efflux of potassium (K+ ions and release of 260 nm materials against E. coli O157:H7 and S. aureus KCTC1621. Moreover, deteriorated cell wall morphology of E. coli O157:H7 and S. aureus KCTC1621 cells treated with (+-lariciresinol at MIC further confirmed its inhibitory effect against the tested pathogens, suggesting it to be an alternative means of antimicrobials.

Chromatin architecture and gene expression in Escherichia coli

DEFF Research Database (Denmark)

Willenbrock, Hanni; Ussery, David

2004-01-01

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

Ethylenediaminetetraacetate and lysozyme improves antimicrobial activities of ovotransferrin against Escherichia coli O157:H7.

Science.gov (United States)

Ko, K Y; Mendoncam, A F; Ismail, H; Ahn, D U

2009-02-01

The aim of this study was to evaluate the effect of EDTA, lysozyme, or the combination of EDTA and lysozyme on the antibacterial activity of ovotransferrin against Escherichia coli O157:H7. Ovotransferrin solutions (20 mg/mL) containing 100 mM NaHCO3 (OS) with added EDTA (2.0 or 2.5 mg/mL), lysozyme (1.0, 1.5, or 2.0 mg/mL), or both were prepared. The antibacterial activities of OS, OSE (OS+EDTA), or OSL (OS+lysozyme) against E. coli O157:H7 in model systems were investigated by turbidity and viability tests. In addition, OSE, OSL, or OSEL (OS+EDTA+lysozyme) was applied to irradiated pork chops and commercial hams to determine whether the solutions had antibacterial activity on meat products. The effect of the initial cell population on the antibacterial activity of OSE, OSL, and OSEL was determined. Ethylenediaminetetraacetate at 2 mg/mL plus OS induced a reduction of approximately 3 to 4 log in viable E. coli O157:H7 cells in brain heart infusion broth media, and 1 mg/mL of lysozyme plus OS resulted in a reduction of approximately 0.5 to 1.0 log during a 36-h incubation at 35 degrees C. However, neither OSE nor OSEL showed a significant antibacterial effect on pork chops and hams during storage at 10 degrees C. The initial cell number in media did not affect the antibacterial activity of OSE or OSEL against E. coli O157:H7. This study demonstrates that combinations of ovotransferrin, NaHCO3, and EDTA have the potential to control E. coli O157:H7.

Current pathogenic Escherichia coli foodborne outbreak cases and therapy development.

Science.gov (United States)

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

2017-08-01

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

The ferric aerobactin receptor IutA, a protein isolated on agarose column, is not essential for uropathogenic Escherichia coli infection El receptor de aerobactina IutA, una proteína aislada en columna de agarosa, no es esencial para la infección por Escherichia coli uropatógena O receptor de aerobactina IutA, uma proteína isolada em coluna de agarose, não é essencial para a infecção por Escherichia coli uropatogênica

Directory of Open Access Journals (Sweden)

Taise Natali Landgraf

2012-04-01

Full Text Available Although many proteins have been described involved in Escherichia coli colonization and infection, only few reports have shown lectins as important components in these processes. Because the mechanisms underlying E. coli colonization process involving lectins are not fully understood, we sought to identify the presence of other non-described lectins in E. coli. Here, we isolated a 75-kDa protein from E. coli on Sepharose column and identified it as ferric aerobactin receptor (IutA. Since IutA is controversially associated with virulence of some E. coli strains, mainly in uropathogenic E. coli (UPEC, we evaluated the presence of iutA gene in UPEC isolated from patients with urinary infection. This gene was present in only 38% of the isolates, suggesting a weak association with virulence. Because there is a redundancy in the siderophore-mediated uptake systems, we suggest that IutA can be advantageous but not essential for UPEC.La falta de una clara comprensión de los mecanismos de participación de las lectinas en el proceso de colonización por Escherichia coli, nos motivó a identificar la presencia de otras lectinas que no han sido descritas en E. coli. En este estudio, se aisló una proteína de 75kDa de E. coli en una columna de Sepharosa, correspondiente al receptor de aerobactina (IutA. La asociación de IutA con cepas virulentas de E coli es controvertido, especialmente en E. coli uropatógena (UPEC, lo que nos llevó a evaluar la presencia del gen iutA en UPECs aisladas de pacientes con infección urinaria. El gen estaba presente en 38% de los aislamientos, lo que sugiere una débil asociación con la virulencia. Debido a la existencia de redundancia en los sistemas de captura de hierro, se sugiere que IutA puede ser una ventaja, sin embargo no es esencial para la UPEC.Apenas alguns relatos na literatura demonstram que lectinas são importantes nos processos de colonização e infecção por Escherichia coli. A falta de compreensão

Impact of dry chilling on the genetic diversity of Escherichia coli on beef carcasses and on the survival of E. coli and E. coli O157.

Science.gov (United States)

Visvalingam, Jeyachchandran; Liu, Yang; Yang, Xianqin

2017-03-06

The objective of this study was to examine the effect of dry chilling on the genetic diversity of naturally occurring Escherichia coli on beef carcasses, and to examine whether two populations of E. coli recovered from carcasses during chilling and E. coli O157 differed in their response to desiccation. Isolates of E. coli were obtained from beef carcasses during a 67h dry chilling process and were genotyped using multiple-locus variable-number tandem-repeat analysis (MLVA). Ten E. coli genotypes found only at 0h (group A) and found more than once (group B), as well as five strains of E. coli O157 (group C) were inoculated on stainless steel coupons and their survival was examined after exposure to 75 and 100% relative humidity (RH) at 0 or 35°C for 67h. A total of 450 E. coli isolates were obtained, with 254, 49, 49, 51, 23, 20, and 4 from 0, 1, 2, 4, 6, 8 and 24h of chilling, respectively. No E. coli were recovered at 67h. MLVA of the isolates revealed 173 distinct genotypes. Genetic diversity of E. coli isolates, defined as ratio of the number of isolates to the number of genotypes, remained between 2.3 and 1.3 during the 24h of chilling. All strains inoculated on stainless steel coupons and exposed to 75% RH at 35°C were completely inactivated, irrespective of their groups. Inactivation of E. coli of the three groups was not significantly (P>0.05) different by exposure to 75% RH at 0°C. The findings indicate that the genetic diversity of E. coli on beef carcasses was not affected by dry chilling. In addition, inactivation of E. coli genotypes and E. coli O157 by desiccation on stainless steel simulating dry chilling conditions did not differ significantly (P>0.05). Thus, dry chilling may be used as an effective antimicrobial intervention for beef carcasses. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Quantification of contamination of lettuce by GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium

NARCIS (Netherlands)

Franz, Eelco; Visser, Anna A; Van Diepeningen, Anne D; Klerks, Michel M; Termorshuizen, Aad J; van Bruggen, Ariena H C

The primary objective of this study was to determine the possibility of internalization of GFP-expressing Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium (S. Typhimurium) strains MAE 110 (multi-cellular morphology) and 119 (wild type morphology) into lettuce seedlings (Lactuca

Assessments of Total and Viable Escherichia coli O157:H7 on Field and Laboratory Grown Lettuce

Science.gov (United States)

Moyne, Anne-Laure; Harris, Linda J.; Marco, Maria L.

2013-01-01

Leafy green produce has been associated with numerous outbreaks of foodborne illness caused by strains of Escherichia coli O157:H7. While the amounts of culturable E. coli O157:H7 rapidly decline after introduction onto lettuce in the field, it remains to be determined whether the reduction in cell numbers is due to losses in cell viability, cell injury and a subsequent inability to be detected by standard laboratory culturing methods, or a lack of adherence and hence rapid removal of the organism from the plants during application. To assess which of these options is most relevant for E. coli O157:H7 on leafy green produce, we developed and applied a propidium monoazide (PMA) real-time PCR assay to quantify viable (with PMA) and total (without PMA) E. coli O157:H7 cells on growth chamber and field-grown lettuce. E. coli O157:H7, suspended in 0.1% peptone, was inoculated onto 4-week-old lettuce plants at a level of approximately 106 CFU/plant. In the growth chamber at low relative humidity (30%), culturable amounts of the nontoxigenic E. coli O157:H7 strain ATCC 700728 and the virulent strain EC4045 declined 100 to 1000-fold in 24 h. Fewer E. coli O157:H7 cells survived when applied onto plants in droplets with a pipette compared with a fine spray inoculation. Total cells for both strains were equivalent to inoculum levels for 7 days after application, and viable cell quantities determined by PMA real-time PCR were approximately 104 greater than found by colony enumeration. Within 2 h after application onto plants in the field, the number of culturable E. coli ATCC 700728 was reduced by up to 1000-fold, whereas PCR-based assessments showed that total cell amounts were equivalent to inoculum levels. These findings show that shortly after inoculation onto plants, the majority of E. coli O157:H7 cells either die or are no longer culturable. PMID:23936235

Vaccination with killed whole-cells of Escherichia coli O157:H7 hha mutant emulsified with an adjuvant induced vaccine strain-specific serum antibodies and reduced E. coli O157:H7 fecal shedding in cattle

Science.gov (United States)

Escherichia coli O157:H7 (O157) can cause from a mild diarrheal illness to hemorrhagic colitis and hemolytic uremic syndrome in humans. Cattle are the primary reservoir for O157 and fecal shedding of O157 by these animals is a major risk factor in contamination of cattle hides and carcasses at slaug...

The incidence and antibiotics susceptibility of Escherichia coli O157 ...

African Journals Online (AJOL)

STORAGESEVER

2010-02-22

Feb 22, 2010 ... The incidence of Escherichia coli 0157: H7 was assessed in meat samples from slaughtered cattle in. Ibadan metropolis by culturing ... high quality farm to fork wholesome and safe meat for public consumption in Nigeria. Key words: EHEC .... Prevalence and in vitro antimicrobial susceptibility. Trop. Vet. 26.

Investigation of carbon storage regulation network (csr genes) and phenotypic differences between acid sensitive and resistant Escherichia coli O157:H7 strains

Science.gov (United States)

Background: Escherichia coli O157:H7 and related serotype strains have previously been shown to vary in acid resistance, however, little is known about strain specific mechanisms of acid resistance. We examined sensitive and resistant E. coli strains to determine the effects of growth in minimal and...

Verocytotoxin-producing Escherichia coli O26 in raw water buffalo (Bubalus bubalis) milk products in Italy.

Science.gov (United States)

Lorusso, Vanessa; Dambrosio, Angela; Quaglia, Nicoletta Cristiana; Parisi, Antonio; La Salandra, Giovanna; Lucifora, Giuseppe; Mula, Giuseppina; Virgilio, Sebastiano; Carosielli, Leonardo; Rella, Addolorata; Dario, Marco; Normanno, Giovanni

2009-08-01

Escherichia coli 026 is known as a verocytotoxin-producing E. coli (VTEC) organism that causes severe foodborne diseases such as hemorrhagic colitis and hemolytic uremic syndrome. Although cattle are the most important reservoir of VTEC, only a few reports on the role of water buffalo (Bubalus bubalis) as a reservoir of VTEC and on the presence of these organisms in their milk are available. However, in Southern Italy, where water buffalo are intensively reared, an outbreak of hemolytic uremic syndrome due to E. coli 026 has recently been reported, in which the consumption of typical dairy products was considered to be a common risk factor. The aims of this work were to assess the prevalence of E. coli O26 in raw water buffalo milk, to characterize the virulence gene profiles of the isolates, and to evaluate their phenotypic antimicrobial resistance pattern. Of 160 analyzed samples, 1 (0.6%) tested positive for E. coli O26, and the isolate showed the stx1+/stx2+/eae-/hlyA+ genotypic profile. The strain showed resistance against glycopeptides, macrolides, and penicillins. The presence of VTEC organisms in raw water buffalo milk could be considered to be a potential threat to consumers; however, the strict adherence to the processes used in the preparation of the most common buffalo dairy products could strongly mitigate the foodborne risk. To our knowledge, this article reports the first isolation and characterization of E. coli O26 VTEC in raw water buffalo milk.

Efeito do tempo de conservação de polimorfonucleares do sangue de bezerros sobre o metabolismo oxidativo e a atividade de fagocitose de Escherichia coli

OpenAIRE

BOHLAND, Elizabeth; SÁ-ROCHA, Vanessa de Moura; CYRILLO, Fernanda Cavallini; BENESI, Fernando José

2008-01-01

Foram avaliados os efeitos do tempo sobre o metabolismo oxidativo e a fagocitose de Escherichia coli, em amostras de polimorfonucleares (PMN) do sangue, de cinco bezerros hígidos, conservadas em banho de gelo por duas (t2), quatro (t4), seis (t6), 12 (t12) e 24 (t24) horas. O metabolismo oxidativo foi avaliado utilizando o Diacetato 2' 7' Diclorofluoresceína (DCFH-DA) e a E. coli, como estímulo. Para a fagocitose a mesma bactéria foi utilizada. As amostras foram analisadas por citometria de f...

Curli fimbriae are conditionally required in Escherichia coli O157:H7 for initial attachment and biofilm formation.

Science.gov (United States)

Carter, Michelle Qiu; Louie, Jacqueline W; Feng, Doris; Zhong, Wayne; Brandl, Maria T

2016-08-01

Several species of enteric pathogens produce curli fimbriae, which may affect their interaction with surfaces and other microbes in nonhost environments. Here we used two Escherichia coli O157:H7 outbreak strains with distinct genotypes to understand the role of curli in surface attachment and biofilm formation in several systems relevant to fresh produce production and processing. Curli significantly enhanced the initial attachment of E. coli O157:H7 to spinach leaves and stainless steel surfaces by 5-fold. Curli was also required for E. coli O157:H7 biofilm formation on stainless steel and enhanced biofilm production on glass by 19-27 fold in LB no-salt broth. However, this contribution was not observed when cells were grown in sterile spinach lysates. Furthermore, both strains of E. coli O157:H7 produced minimal biofilms on polypropylene in LB no-salt broth but considerable amounts in spinach lysates. Under the latter conditions, curli appeared to slightly increase biofilm production. Importantly, curli played an essential role in the formation of mixed biofilm by E. coli O157:H7 and plant-associated microorganisms in spinach leaf washes, as revealed by confocal microscopy. Little or no E. coli O157:H7 biofilms were detected at 4 °C, supporting the importance of temperature control in postharvest and produce processing environments. Published by Elsevier Ltd.

Genomic Variability of O Islands Encoding Tellurite Resistance in Enterohemorrhagic Escherichia coli O157:H7 Isolates

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Taylor, Diane E.; Rooker, Michelle; Keelan, Monika; Ng, Lai-King; Martin, Irene; Perna, Nicole T.; Burland, N. T. Valerie; Blattner, Fredrick R.

2002-01-01

Strains of Escherichia coli causing enterohemorrhagic colitis belonging to the O157:H7 lineage are reported to be highly related. Fifteen strains of E. coli O157:H7 and 1 strain of E. coli O46:H− (nonflagellated) were examined for the presence of potassium tellurite resistance (Ter). Ter genes comprising terABCDEF were shown previously to be part of a pathogenicity island also containing integrase, phage, and urease genes. PCR analysis, both conventional and light cycler based, demonstrated that about one-half of the Ter E. coli O157:H7 strains (6 of 15), including the Sakai strain, which has been sequenced, carried a single copy of the Ter genes. Five of the strains, including EDL933, which has also been sequenced, contained two copies. Three other O157:H7 strains and the O46:H− strain did not contain the Ter genes. In strains containing two copies, the Ter genes were associated with the serW and serX tRNA genes. Five O157:H7 strains resembled the O157 Sakai strain whose sequence contained one copy, close to serX, whereas in one isolate the single copy was associated with serW. There was no correlation between Ter and the ability to produce Shiga toxin ST1 or ST2. The Ter MIC for most strains, containing either one or two copies, was 1,024 μg/ml, although for a few the MIC was intermediate, 64 to 128 μg/ml, which could be increased to 512 μg/ml by pregrowth of strains in subinhibitory concentrations of potassium tellurite. Reverse transcriptase PCR analysis confirmed that in most strains Ter was constitutive but that in the rest it was inducible and involved induction of terB and terC genes. Only the terB, -C, -D, and -E genes are required for Ter. The considerable degree of homology between the ter genes on IncH12 plasmid R478, which originated in Serratia marcescens, and pTE53, from an E. coli clinical isolate, suggests that the pathogenicity island was acquired from a plasmid. This work demonstrates diversity among E. coli O157:H7 isolates, at least as

Acid and alcohol tolerance of Escherichia coli O157:H7 in pulque, a typical Mexican beverage.

Science.gov (United States)

Gómez-Aldapa, Carlos A; Díaz-Cruz, Claudio A; Villarruel-López, Angelica; Del Refugio Torres-Vitela, M; Rangel-Vargas, Esmeralda; Castro-Rosas, Javier

2012-03-01

Pulque is a traditional Mexican fermented alcoholic beverage produced from the nectar of maguey agave plants. No data exist on the behavior of Escherichia coli O157:H7 in agave nectar and pulque. An initial trial was done of the behavior of E. coli O157:H7 during fermentation of nectar from a single producer, a nectar mixture from different producers and "seed" pulque. A second trial simulating artisanal pulque production was done by contaminating fresh nectar with a cocktail of three E. coli O157:H7 strains, storing at 16 ° and 22 °C for 14 h, adding seed pulque and fermenting until pulque was formed. A third trial used pulque from the second trial stored at 22 °C as seed to ferment fresh nectar at 22 °C for 48 h (fermentation cycle). This procedure was repeated for an additional two fermentation cycles. During incubation at 16 ° or 22 °C in the first trial, the E. coli O157:H7 strains multiplied in both the single producer nectar and nectar mixture, reaching maximum concentration at 12h. E. coli O157:H7 cell concentration then decreased slowly, although it survived at least 72 h in both fermented nectars. E. coli O157:H7 did not multiply in the seed pulque but did survive at least 72 h. In the second trial, the numbers of E. coli O157:H7 increased approximately 1.5 log CFU/ml at 22 °C and 1.2 log CFU/ml at 16 °C after 14 h. After seed pulque was added, E. coli O157:H7 concentration decreased to approximately 2 log CFU/ml, and then remained constant until pulque was produced. In the third trial, the E. coli O157:H7 cells multiplied and survived during at least three nectar fermentation cycles. The results suggest that E. coli O157:H7 can develop acid and alcohol tolerance in pulque, and constitutes a public health risk for pulque consumers. Copyright © 2011 Elsevier B.V. All rights reserved.

Uso de antibiótico, de probiótico e de homeopatia em frangos de corte criados em ambiente de conforto, inoculados ou não com Escherichia coli Use of antibiotic, probiotic and homeopathy, inoculated or not with Escherichia coli, for broilers reared under comfort environment

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Adriano José Boratto

2004-12-01

Full Text Available Para avaliar o efeito do uso de antibiótico, de probiótico e de homeopatia em frangos de corte, inoculados ou não com Escherichia coli, foram distribuídos 672 frangos machos, Avian Farm, em delineamento inteiramente casualizado em esquema fatorial com oito tratamentos (quatro aditivos x com ou sem inoculação e seis repetições, tendo 14, 12 e 7 aves por unidade experimental, respectivamente, de acordo com os períodos 1 a 11, 12 a 21 e 22 a 42 dias de idade. As aves foram alojadas em salas climatizadas em ambiente de conforto, de acordo com o manual da linhagem. Os tratamentos foram constituídos de: controle negativo (sem aditivo, antibiótico (virginiamicina + nitrovin, probiótico (meio de cultura de Lactobacilus acidophillus, Enterococcus faecium e Saccharomices cerevisiae e homeopatia (nosódio de Escherichia coli. Observou-se que as aves tratadas com antibiótico e probiótico apresentaram maior ganho de peso no período de 1 a 21 dias, com melhor conversão alimentar para aquelas tratadas com antibiótico, embora no período total de 1 a 42 dias não tenha havido diferença entre os tratamentos. A inoculação da Escherichia coli piorou o desempenho das aves, aumentando o peso relativo do coração, do fígado e dos intestinos, enquanto o uso de antibiótico e de probiótico melhorou o desempenho das aves no período de 1 a 21 dias.The effect of antibiotic, probiotic and homeopathy in broilers inoculated or not with Escherichia coli was evaluated. Six hundred and seventy two male broilers of Avian Farm strain were assigned to a completely randomized design, in a factorial scheme, with eight treatments (four additives x inoculation or not and six replicates, with 14, 12 and 7 birds by experimental box, respectively, according to the periods from 1 to 11, from 12 to 21 and from 22 to 42 days of age. The birds were allotted to acclimatized chambers, under comfort environment, according to the strain recommendations. The treatments

Inactivation of Escherichia coli O157:H7 on stainless steel upon exposure to Paenibacillus polymyxa biofilms.

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Kim, Seonhwa; Bang, Jihyun; Kim, Hoikyung; Beuchat, Larry R; Ryu, Jee-Hoon

2013-11-01

We investigated the potential use of biofilm formed by a competitive-exclusion (CE) microorganism to inactivate Escherichia coli O157:H7 on a stainless steel surface. Five microorganisms showing inhibitory activities against E. coli O157:H7 were isolated from vegetable seeds and sprouts. The microorganism with the greatest antimicrobial activity was identified as Paenibacillus polymyxa (strain T5). In tryptic soy broth (TSB), strain T5 reached a higher population at 25 °C than at 12 or 37 °C without losing inhibitory activity against E. coli O157:H7. When P. polymyxa (6 log CFU/mL) was co-cultured with E. coli O157:H7 (2, 3, 4, or 5 log CFU/mL) in TSB at 25 °C, the number of E. coli O157:H7 decreased significantly within 24h. P. polymyxa formed a biofilm on stainless steel coupons (SSCs) in TSB at 25 °C within 24h, and cells in biofilms, compared to attached cells without biofilm formation, showed significantly increased resistance to a dry environment (43% relative humidity [RH]). With the exception of an inoculum of 4 log CFU/coupon at 100% RH, upon exposure to biofilm formed by P. polymyxa on SSCs, populations of E. coli O157:H7 (2, 4, or 6 log CFU/coupon) were significantly reduced within 48 h. Most notably, when E. coli O157:H7 at 2 log CFU/coupon was applied to SSCs on which P. polymyxa biofilm had formed, it was inactivated within 1h, regardless of RH. These results will be useful when developing strategies using biofilms produced by competitive exclusion microorganisms to inactivate foodborne pathogens in food processing environments. © 2013.

Assumptions of acceptance sampling and the implications for lot contamination: Escherichia coli O157 in lots of Australian manufacturing beef.

Science.gov (United States)

Kiermeier, Andreas; Mellor, Glen; Barlow, Robert; Jenson, Ian

2011-04-01

The aims of this work were to determine the distribution and concentration of Escherichia coli O157 in lots of beef destined for grinding (manufacturing beef) that failed to meet Australian requirements for export, to use these data to better understand the performance of sampling plans based on the binomial distribution, and to consider alternative approaches for evaluating sampling plans. For each of five lots from which E. coli O157 had been detected, 900 samples from the external carcass surface were tested. E. coli O157 was not detected in three lots, whereas in two lots E. coli O157 was detected in 2 and 74 samples. For lots in which E. coli O157 was not detected in the present study, the E. coli O157 level was estimated to be contaminated carton, the total number of E. coli O157 cells was estimated to be 813. In the two lots in which E. coli O157 was detected, the pathogen was detected in 1 of 12 and 2 of 12 cartons. The use of acceptance sampling plans based on a binomial distribution can provide a falsely optimistic view of the value of sampling as a control measure when applied to assessment of E. coli O157 contamination in manufacturing beef. Alternative approaches to understanding sampling plans, which do not assume homogeneous contamination throughout the lot, appear more realistic. These results indicate that despite the application of stringent sampling plans, sampling and testing approaches are inefficient for controlling microbiological quality.

Efficacy of integrated treatment of UV light and low dose gamma irradiation on Escherichia coli O157:H7 and Salmonella enterica on grape tomatoes

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Efficacy of integrated treatment of UVC and low dose Gamma irradiation to inactivate mixed Strains of Escherichia coli O157:H7 and Salmonella enterica inoculated on whole Grape tomatoes was evaluated. A mixed bacterial cocktail composed of a three strain mixture of E. coli O157:H7 (C9490, E02128 an...

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

Science.gov (United States)

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

2016-10-01

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

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

Modeling the inactivation of Escherichia coli 0157:H7 and uropathogenic E.coli in ground chicken by high pressure processing and thymol

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Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compare the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing...

Modeling the inactivatin of Escherichia coli 0157:H7 and uropathogenic E. coli in ground beef by high pressure processing and citral

Science.gov (United States)

Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compared the resistance of iPEC (O157:H7) to UPEC in ground beef using High Pressure Processing...

Antibiotic resistant Salmonella and Escherichia coli isolated from ...

African Journals Online (AJOL)

Results: A hundred and four indigenous chicken rectal swabs were analysed, of which 67.3% were contaminated with Escherichia coli and 12.5% with Salmonella typhimurium. Seventy Escherichia coli isolates showed resistance phenotypes to one, two or more antibiotics. The most common antimicrobial resistance pattern ...

Placental and colostral transfer of antibodies reactive with enteropathogenic Escherichia coli intimins α, β, or γ

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Silvia P.N. Altman

2017-11-01

Full Text Available Objective: Intimins are protein adhesins of enteropathogenic Escherichia coli and enterohemorrhagic E. coli capable of inducing attachment and effacement lesions in enterocytes. Anti-intimin antibodies are important for the protection from enteropathogenic E. coli and enterohemorrhagic E. coli infections because these antibodies inhibit bacterial adhesion and impair the initial step of the pathogenesis. We studied the transfer of maternal anti-intimin antibodies from healthy Brazilian mothers to their newborns through the placenta and colostrum. Methods: Serum immunoglobulin G and secretory immunoglobulin A antibodies against conserved and variable regions of intimins α, β, and γ were analyzed using an enzyme linked-immunosorbent assay in the blood and colostrum from 45 healthy women as well as cord blood serum samples from their newborns. Results: The concentrations of antibodies reactive with α intimin were significantly lower than those of anti-γ and anti-conserved intimin antibodies in the colostrum samples. IgG serum antibodies reactive with all the subtypes of intimins were transferred to the newborns, but the concentrations of anti-conserved intimin serum antibodies were significantly higher in mothers and newborns than concentrations of antibodies against variable regions. The patterns of IgG transfer from mothers to newborns were similar for all anti-intimin antibodies. These values are similar to the percentage transference of total IgG. Conclusions: Anti-intimin antibodies are transferred from mothers to newborns through the placenta, and reinforce the protection provided by breastfeeding against diarrheagenic E. coli infections. Resumo: Objetivo: As Intiminas são adesinas proteicas de Escherichia coli enteropatogênicas e enterohemorrágicas capazes de induzir as lesões “attaching and effacing” nos enterócitos. Anticorpos anti-intiminas são importantes para a proteção contra infecções por E. coli enteropatogênica e

Occurrence of adhesin-encoding operons in Escherichia coli isolated from breeders with salpingitis and chicks with omphalitis Ocorrência de operons codificadores de adesinas em Escherichia coli isolada de aves reprodutoras com salpingite e de pintinhos com onfalite

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Terezinha Knöbl

2006-06-01

Full Text Available The occurrence of fim, pap and sfa operons in Escherichia coli isolated from breeders with salpingitis and chicks with omphalitis was evaluated. Analysis of 100 E. coli isolates, by colony hybridization tests, showed that 78 (78% were fim+, one (1% was sfa+, seven (7% were fim+ associated with pap+, eigth (8% were fim+ and sfa+, one (1% was fim+pap+sfa+ and five (5% isolates did not hybridize with any probe. These results suggest that fim adhesion-encoding operon plays an important role in pathogenesis of E. coli infection in chickens with salpingitis and omphalitis.Ocorrência dos operons fim, pap e sfa em amostras de Escherichia coli isoladas de reprodutoras com salpingite e pintinhos com onfalite foi avaliada. A análise de 100 amostras através dos testes de hibridização de colônia mostrou que 78 (78% amostras eram fim+, uma (1% era sfa+, sete (7% eram fim+ associada a pap+, oito (8% eram fim+ e uma (1% era fim+pap+sfa+ e cinco (5% amostras não hibridizaram com nenhuma sonda. Estes resultados sugerem que o operon fim pode ter um importante papel na patogenia da infecção de Escherichia coli em reprodutoras com salpingite e pintinhos com onfalite.

New evidence on the role of catalase in Escherichia coli-mediated biocorrosion

International Nuclear Information System (INIS)

Baeza, S.; Vejar, N.; Gulppi, M.; Azocar, M.; Melo, F.; Monsalve, A.; Pérez-Donoso, J.; Vásquez, C.C.; Pavez, J.; Zagal, J.H.; Zhou, X.; Thompson, G.E.; Páez, M.A.

2013-01-01

Highlights: ► MIC on stainless by catalase deficient Escherichia coli bacteria reveals the enzyme influence. ► The localized damage was greater in the presence of the wild E. coli. ► Catalase assists oxygen generation by disproportionation of H 2 O 2 to H 2 O and O 2 . - Abstract: The role of catalase on the microbiologically influenced corrosion mechanism by Escherichia coli (E. coli) has been examined, employing wild type and catalase-deficient cells. The bacteria were cultured for different times in the presence of AISI 316L stainless steel samples. The morphologies of the metallic surfaces covered by biofilms were studied by optical microscopy. The localized corrosion catalyzed by the bacteria was followed by scanning electron microscopy after immersion in the bacterial culture for different times. Susceptibility to corrosion was further investigated by potentiodynamic measurements. It was found that wild type E. coli is more aggressive than the mutant one, suggesting a role for catalase in increasing the kinetics of the cathodic reaction and, consequently, the global corrosion process. This correlates with oxygen uptake kinetics, as determined by differential pulse voltammetry on a pyrolytic graphite electrode modified with cobalt phthalocyanine, which was higher in the presence of wild type E. coli. When H 2 O 2 was deliberately added to the culture medium, wild type E. coli catalyzed oxygen disproportionation more efficiently than the mutant derivative, thus limiting H 2 O 2 accumulation in the medium and, hence, bacterial poisoning. In fact, the reduced adhesion of mutant cells to the metal substrate is apparently the result of H 2 O 2 accumulation in the culture broth. Thus, the rapid consumption of oxygen and peroxide in the presence of wild type E. coli is associated with the catalysis of H 2 O 2 disproportionation to water and oxygen. On the stainless steel, however, a dual mechanism of oxygen reduction, i.e. through formation of hydrogen peroxide

Protozoan Predation of Escherichia coli O157:H7 Is Unaffected by the Carriage of Shiga Toxin-Encoding Bacteriophages.

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Carrie E Schmidt

Full Text Available Escherichia coli O157:H7 is a food-borne bacterium that causes hemorrhagic diarrhea and hemolytic uremic syndrome in humans. While cattle are a known source of E. coli O157:H7 exposure resulting in human infection, environmental reservoirs may also be important sources of infection for both cattle and humans. Bacteriophage-encoded Shiga toxins (Stx carried by E. coli O157:H7 may provide a selective advantage for survival of these bacteria in the environment, possibly through their toxic effects on grazing protozoa. To determine Stx effects on protozoan grazing, we co-cultured Paramecium caudatum, a common ciliate protozoon in cattle water sources, with multiple strains of Shiga-toxigenic E. coli O157:H7 and non-Shiga toxigenic cattle commensal E. coli. Over three days at ambient laboratory temperature, P. caudatum consistently reduced both E. coli O157:H7 and non-Shiga toxigenic E. coli populations by 1-3 log cfu. Furthermore, a wild-type strain of Shiga-toxigenic E. coli O157:H7 (EDL933 and isogenic mutants lacking the A subunit of Stx 2a, the entire Stx 2a-encoding bacteriophage, and/or the entire Stx 1-encoding bacteriophage were grazed with similar efficacy by both P. caudatum and Tetrahymena pyriformis (another ciliate protozoon. Therefore, our data provided no evidence of a protective effect of either Stx or the products of other bacteriophage genes on protozoan predation of E. coli. Further research is necessary to determine if the grazing activity of naturally-occurring protozoa in cattle water troughs can serve to decrease cattle exposure to E. coli O157:H7 and other Shiga-toxigenic E. coli.

Molecular prophage typing of avian pathogenic Escherichia coli.

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Kwon, Hyuk-Joon; Seong, Won-Jin; Kim, Jae-Hong

2013-03-23

Escherichia coli prophages confer virulence and resistance to physico-chemical, nutritional, and antibiotic stresses on their hosts, and they enhance the evolution of E. coli. Thus, studies on profiles of E. coli prophages are valuable to understand the population structure and evolution of E. coli pathogenicity. Large terminase genes participate in phage genome packaging and are one of the cornerstones for the identification of prophages. Thus, we designed primers to detect 16 types of large terminase genes and analyzed the genomes of 48 E. coli and Shigella reference strains for the prophage markers. We also investigated the distribution of the 16 prophage markers among 92 avian pathogenic E. coli (APEC) strains. APEC strains were classified into 61 prophage types (PPTs). Each strain was different from the reference strains as measured by the PPTs and from the frequency of each prophage marker. Investigation of the distribution of prophage-related serum resistance (bor), toxin (stx1 and cdtI), and T3SS effector (lom, espK, sopE, nleB, and ospG) genes revealed the presence of bor (44.1%), lom (95.5%) and cdtI (9.1%) in APEC strains with related prophages. Therefore, the molecular prophage typing method may be useful to understand population structure and evolution of E. coli pathogenicity, and further studies on the mobility of the prophages and the roles of virulence genes in APEC pathogenicity may be valuable. Copyright © 2012 Elsevier B.V. All rights reserved.

Complete genome sequences of Escherichia coli strains 1303 and ECC-1470 isolated from bovine mastitis

NARCIS (Netherlands)

Leimbach, Andreas; Poehlein, Anja; Witten, Anika; Scheutz, Flemming; Schukken, Ynte|info:eu-repo/dai/nl/075051907; Daniel, Rolf; Dobrindt, Ulrich

2016-01-01

Escherichia coli is the leading causative agent of acute bovine mastitis. Here, we report the complete genome sequence of E. coli O70:H32 strain 1303, isolated from an acute case of bovine mastitis, and E. coli Ont:Hnt strain ECC-1470, isolated from a persistent infection.

Toward an international standard for PCR-based detection of Escherichia coli O157 - Part 1. Assay development and multi-center validation

DEFF Research Database (Denmark)

Abdulmawjood, A.; Bulte, M.; Cook, N.

2003-01-01

As part of a major European research project, a diagnostic PCR assay, including an internal amplification control, was developed and validated in a collaborative trial for the detection of Escherichia coli O157. The assay is based on amplification of sequences of the rJbE O157 gene. The collabora...

Determinação de parâmetros cinéticos da inativação térmica de Escherichia coli em lodo de esgoto Determining kinetic parameters for thermal inactivation of Escherichia coli in sewage sludge

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Odinei Fogolari

2012-09-01

Full Text Available O presente trabalho objetivou determinar parâmetros cinéticos da inativação térmica de Escherichia coli em lodo de esgoto. Os ensaios foram realizados em laboratório pelo método do frasco de três bocas nas temperaturas de 45, 50, 55, 60 e 65ºC. Os resultados indicaram que a cinética de inativação térmica deste microrganismo pode ser descrita por um modelo de primeira ordem. A resistência da bactéria é reduzida consideravelmente em temperaturas acima de 55ºC. A energia de inativação encontrada foi 2,48x10(5 J.mol-1. O tempo de redução decimal D55ºC foi de 3,61 minutos e o coeficiente térmico z foi 8,3ºC.The present study aimed to determine the kinetic parameters of thermal inactivation of Escherichia coli in sewage sludge. The tests were performed in the laboratory using the three-neck flask method at temperatures of 45, 50, 55, 60 and 65ºC. The results indicated that the thermal inactivation kinetic of this microorganism can be described by a first order model. The resistance of bacteria is greatly reduced at temperatures above 55ºC. The inactivation energy was found 2.48x10(5 J.mol-1. The decimal reduction time D55ºC was 3.61 minutes and the thermal coefficient z was 8.3ºC.

A sensitive lateral flow biosensor for Escherichia coli O157:H7 detection based on aptamer mediated strand displacement amplification

Energy Technology Data Exchange (ETDEWEB)

Wu, Wei [College of Food Science and Engineering, Ocean University of China, Qingdao 266003 (China); Zhao, Shiming [Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530 (China); Mao, Yiping [Yueyang Institute for Food and Drug Control, Yueyang 430198 (China); Fang, Zhiyuan [Affiliated Tumor Hospital of Guangzhou Medical University, Guangzhou 510095 (China); Lu, Xuewen [Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530 (China); Zeng, Lingwen, E-mail: zeng6@yahoo.com [Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530 (China)

2015-02-25

Highlights: • Limit of detection as low as 10 CFU mL{sup −1}Escherichia coli O157:H7. • No need of antibodies and substituted with aptamers. • Isothermal strand displacement amplification for signal amplification. • Results observed by the naked eye. • Great potential application in the area of food control. - Abstract: Foodborne diseases caused by pathogens are one of the major problems in food safety. Convenient and sensitive point-of-care rapid diagnostic tests for food-borne pathogens have been a long-felt need of clinicians. Commonly used methods for pathogen detection rely on conventional culture-based tests, antibody-based assays and polymerase chain reaction (PCR)-based techniques. These methods are costly, laborious and time-consuming. Herein, we present a simple and sensitive aptamer based biosensor for rapid detection of Escherichia coli O157:H7 (E. coli O157:H7). In this assay, two different aptamers specific for the outmembrane of E. coli O157:H7 were used. One of the aptamers was used for magnetic bead enrichment, and the other was used as a signal reporter for this pathogen, which was amplified by isothermal strand displacement amplification (SDA) and further detected by a lateral flow biosensor. Only the captured aptamers on cell membrane were amplified, limitations of conventional DNA amplification based method such as false-positive can be largely reduced. The generated signals (red bands on the test zone of a lateral flow strip) can be unambiguously read out by the naked eye. As low as 10 colony forming units (CFU) of E. coli O157:H7 were detected in this study. Without DNA extraction, the reduced handling and simpler equipment requirement render this assay a simple and rapid alternative to conventional methods.

A sensitive lateral flow biosensor for Escherichia coli O157:H7 detection based on aptamer mediated strand displacement amplification

International Nuclear Information System (INIS)

Wu, Wei; Zhao, Shiming; Mao, Yiping; Fang, Zhiyuan; Lu, Xuewen; Zeng, Lingwen

2015-01-01

Highlights: • Limit of detection as low as 10 CFU mL −1 Escherichia coli O157:H7. • No need of antibodies and substituted with aptamers. • Isothermal strand displacement amplification for signal amplification. • Results observed by the naked eye. • Great potential application in the area of food control. - Abstract: Foodborne diseases caused by pathogens are one of the major problems in food safety. Convenient and sensitive point-of-care rapid diagnostic tests for food-borne pathogens have been a long-felt need of clinicians. Commonly used methods for pathogen detection rely on conventional culture-based tests, antibody-based assays and polymerase chain reaction (PCR)-based techniques. These methods are costly, laborious and time-consuming. Herein, we present a simple and sensitive aptamer based biosensor for rapid detection of Escherichia coli O157:H7 (E. coli O157:H7). In this assay, two different aptamers specific for the outmembrane of E. coli O157:H7 were used. One of the aptamers was used for magnetic bead enrichment, and the other was used as a signal reporter for this pathogen, which was amplified by isothermal strand displacement amplification (SDA) and further detected by a lateral flow biosensor. Only the captured aptamers on cell membrane were amplified, limitations of conventional DNA amplification based method such as false-positive can be largely reduced. The generated signals (red bands on the test zone of a lateral flow strip) can be unambiguously read out by the naked eye. As low as 10 colony forming units (CFU) of E. coli O157:H7 were detected in this study. Without DNA extraction, the reduced handling and simpler equipment requirement render this assay a simple and rapid alternative to conventional methods

NanoSIMS50 analyses of Ar/18O2 plasma-treated Escherichia coli bacteria

International Nuclear Information System (INIS)

Clément, F; Lecoq, E; Duday, D; Audinot, J-N; Lentzen, E; Penny, C; Cauchie, H-M; Choquet, P; Belmonte, T

2011-01-01

Reactive oxygen species (ROS) can be produced by electrical discharges and can be transported in uncharged regions by gas flows, in the so-called afterglows. These species are well known to have bactericidal effects but interaction mechanisms that occur with living micro-organisms remain misunderstood. In order to better understand these interactions, new analysis approaches are necessary. High-lateral-resolution secondary ion mass spectrometry (NanoSIMS) is one of the most promising ways of retrieving additional information on bacteria plasma inactivation mechanisms by combining isotopic imaging of plasma-treated bacteria and the use of 18 O 2 as process gas. Indeed, this technology combines a lateral resolution of a few tens of nanometres that is sufficient to image the interior of bacteria, and a high mass resolution allowing detection of isotopes present in low quantities (a few ppm or lower) within the bacteria. The present paper deals with Ar- 18 O 2 (2%) plasma treatment, through low-pressure microwave late afterglows, of Escherichia coli bacteria and their elemental and isotopic imaging by NanoSIMS. E. coli bacteria have been exposed to this reactive medium for varying treatment duration while keeping all other parameters unchanged. Our main goal is to determine whether the quantity of 18 O fixed in treated bacteria and the NanoSIMS50 lateral resolution are sufficient to give additional information on E. coli bacteria-plasma interaction. (paper)

Comparison of methods for the identification and sub-typing of O157 and non-O157 Escherichia coli serotypes and their integration into a polyphasic taxonomy approach

OpenAIRE

Prieto-Calvo M.A.; Omer M.K.; Alvseike O.; López M.; Alvarez-Ordóñez A.; Prieto M.

2016-01-01

Phenotypic, chemotaxonomic and genotypic data from 12 strains of Escherichia coli were collected, including carbon source utilisation profiles, ribotypes, sequencing data of the 16S–23S rRNA internal transcribed region (ITS) and Fourier transform-infrared (FT-IR) spectroscopic profiles. The objectives were to compare several identification systems for E. coli and to develop and test a polyphasic taxonomic approach using the four methodologies combined for the sub-typing of O157 and non-O157 E...

Assessment of Escherichia coli O157:H7 transference from soil to Iceberg Lettuce via a contaminated harvesting knife

Science.gov (United States)

The potential for coring knives to cross-contaminate lettuce heads with pathogens was evaluated for both ring and blade ends. Rings and blades artificially contaminated with Escherichia coli O157:H7 (EHEC), were used to core three successive heads of iceberg lettuce. The coring rings and blades were...

Improved Design and Ultrasound-assisted Sanitation of Lettuce Harvesting Knives for Minimizing Escherichia coli O157:H7 Contamination

Science.gov (United States)

Laboratory studies have shown that Escherichia coli O157:H7 can be transferred to lettuce during harvesting. Knives used for lettuce coring-in-field (CIF) harvesting are likely to contact soil and consequently could serve as a vehicle for the transmission of food-borne human pathogens from contamin...

Avaliação do padrão coliformes a 45ºC e comparação da eficiência das técnicas dos tubos múltiplos e Petrifilm EC na detecção de coliformes totais e Escherichia coli em alimentos Coliforms at 45ºc and comparison of most probable number method and Petrifilm EC for enumeration of total coliforms and Escherichia coli of foods

Directory of Open Access Journals (Sweden)

M.P. Silva

2006-06-01

Full Text Available Coliformes fecais são definidos como coliformes capazes de fermentar a lactose com produção de gás em 48 h a 45ºC. Escherichia coli, juntamente com algumas cepas de Enterobacter e Klebsiella, podem apresentar essas características. Entretanto, apenas a presença de Escherichia coli em alimentos indica contaminação fecal por ser encontrada em grande quantidade no trato gastrointestinal do homem e animais de sangue quente, não sendo isolada normalmente em outros nichos. A denominação clássica de coliformes fecais foi alterada para coliformes a 45ºC, na Resolução nº 12 da Agência Nacional de Vigilância Sanitária. O objetivo deste trabalho foi avaliar a presença de E. coli entre os coliformes a 45ºC e comparar a eficiência das técnicas dos tubos múltiplos e Petrifilm EC na detecção de coliformes totais e E. coli em queijo Minas, lingüiça frescal, hortaliças e fubá. Petrifilm EC mostrou-se mais sensível na detecção de E. coli em relação ao método de tubos múltiplos, o qual apresentou resultados falso-negativos ou contagens subestimadas de E. coli, principalmente para amostras de alimentos de origem animal. Petrifilm EC foi o mais eficiente e prático, sendo um método alternativo adequado para a enumeração de coliformes totais e E. coli em alimentos.Fecal coliforms are defined as coliforms that ferment lactose with gas production within 48 hours at 45ºC. Escherichia coli and some strains of Enterobacter and Klebsiella show these same characteristics. However, only the presence of E. coli can indicate fecal contamination of foods, because it is abundantly found in the intestinal tract of all warm-blooded animals, including the humans, and it is not usually found in others niches. The classic denomination of fecal coliforms was changed to coliforms at 45ºC in the Resolution nº 12/2001 of the National Surveillance Agency of Brazil. The objectives of this study were to analyse the presence of E. coli among the

Deteksi Produksi Toksin Stx-1 dan Stx-2 dari Escherichia coli O157:H7 Isolat Lokal Hasil Isolasi Feses dan Daging Sapi

Directory of Open Access Journals (Sweden)

I Wayan Suardana

2009-12-01

Full Text Available Shiga toxin produced by Escherichia coli O157:H7 can cause outbreaks and sporadic cases of serioushuman diseases. The diseases are indicated by hemorrhagic colitis and hemolytic uremic syndrome. Meatand meat products have been identified as vehicles of food borne disease caused by E.coli O157:H7. Themain aim of this research was to identify the correlation between the level of E.coli O157:H7 contaminationand the presence of Shiga toxin (Stx1 and Stx2 by applying method of Vero toxin Escherichia coli-ReversePassive Agglutination Test (VTEC-RPLA. The results showed that 3 of 7 isolates and 1 of 4 isolatesisolated from feces of cattle and beef, respectively produced Stx 1 (VT1. In the detection of Stx 2 (VT2, 4of 7 isolates and 1 of 4 isolates, isolated from the same samples were found to produce this toxin.According to all isolates, in this research showed, 1 isolate was found to produce VT2, 4 isolates to produceboth VT1 and VT2, while 6 isolates showed negative results either to VT1 or VT2.

Classification of shiga toxin-producing escherichia coli (STEC) serotypes with hyperspectral microscope imagery

Science.gov (United States)

Non-O157:H7 Shiga toxin-producing Escherichia coli (STEC) strains such as O26, O45, O103, O111, O121 and O145 are recognized as serious outbreak to cause human illness due to their toxicity. Since a conventional microbiological method for cell counting is laborious and time-consuming process, optica...

Survival and interaction of Escherichia coli O104:H4 on Arabidopsis thaliana and lettuce (Lactuca sativa) in comparison to E. coli O157:H7: Influence of plant defense response and bacterial capsular polysaccharide.

Science.gov (United States)

Jang, Hyein; Matthews, Karl R

2018-06-01

Shiga toxin-producing Escherichia coli (STEC) has been associated with illnesses and outbreaks linked to fresh vegetables, prompting a growing public health concern. Most studies regarding interactions of STEC on fresh produce focused on E. coli O157:H7. Limited information is available about survival or fitness of E. coli O104:H4, non-O157 pathogen that was linked to one of the largest outbreaks of hemolytic uremic syndrome in 2011. In this study, survival of E. coli O104:H4 was evaluated on Arabidopsis thaliana plant and lettuce for 5 days compared with E. coli O157:H7, and expression of pathogenesis-realted gene (PR1; induction of plant defense response) was examined by reverse transcription quantitative PCR, and potential influence of capsular polysaccharide (CPS) on the bacterial fitness on plant was investigated. Populations of E. coli O104:H4 strains (RG1, C3493, and LpfA) on Arabidopsis and lettuce were significantly (P E. coli O157:H7 strains (7386 and sakai) at day 5 post-inoculation, indicating E. coli O104:H4 may have better survival ability on the plants. In addition, the E. coli O104:H4 strains produced significantly (P E. coli O157:H7 strains. RG1 strain (1.5-fold) initiated significantly (P E. coli O157:H7 strains 7386 (2.9-fold) and sakai (2.7-fold). Collectively, the results in this study suggests that different level of CPS production and plant defense response initiated by each STEC strain might influence the bacterial survival or persistence on plants. The present study provides better understanding of survival behavior of STEC, particularly E. coli O104:H4, using a model plant and vegetable under pre-harvest conditions with plant defense response. Copyright © 2018 Elsevier Ltd. All rights reserved.

Efficient recovery of fluoroquinolone-susceptible and fluoroquinolone-resistant Escherichia coli strains from frozen samples.

Science.gov (United States)

Lautenbach, Ebbing; Santana, Evelyn; Lee, Abby; Tolomeo, Pam; Black, Nicole; Babson, Andrew; Perencevich, Eli N; Harris, Anthony D; Smith, Catherine A; Maslow, Joel

2008-04-01

We assessed the rate of recovery of fluoroquinolone-resistant and fluoroquinolone-susceptible Escherichia coli isolates from culture of frozen perirectal swab samples compared with the results for culture of the same specimen before freezing. Recovery rates for these 2 classes of E. coli were 91% and 83%, respectively. The majority of distinct strains recovered from the initial sample were also recovered from the frozen sample. The strains that were not recovered were typically present only in low numbers in the initial sample. These findings emphasize the utility of frozen surveillance samples.

Genotypic characterization of virulence factors in Escherichia coli strains from patients with cystitis Caracterização genotípica dos fatores de virulência em amostras de Escherichia coli isoladas de pacientes com cistite

Directory of Open Access Journals (Sweden)

Monique Ribeiro Tiba

2008-10-01

Full Text Available Adhesins (P-fimbriae, S-fimbriae, type 1 fimbriae and afimbrial adhesin, toxins (α-hemolysin and cytotoxic necrotizing factor type 1, iron acquisition systems (aerobactin and host defense avoidance mechanisms (capsule or lipopolysaccharide have been shown to be prevalent in Escherichia coli strains associated with urinary tract infections. In this work, 162 Uropathogenic Escherichia coli (UPEC strains from patients with cystitis were genotypically characterized by polymerase chain reaction (PCR assay. We developed three multiplex PCR assays for virulence-related genes papC, papE/F, papG alleles, fimH, sfa/foc, afaE, hly, cnf-1, usp, cdtB, iucD, and kpsMTII, all of them previously identified in UPEC strains. The PCR assay results identified 158 fimH (97.5%, 86 kpsMTII (53.1%, 53 papC/papEF/papG (32.7%, 45 sfa (27.8%, 42 iucD (25.9%, 41 hly (25.3%, 36 usp (22.2%, 30 cnf-1(18.5% and 10 afa (6.2% strains. No strain was positive for cdtB. In this work, we also demonstrated that adhesins may be multiple within a single strain and that several virulence genes can occur combined in association.Adesinas (Fímbria P, fímbria S, fímbria do tipo 1 e a adesina afimbrial, toxinas (α-hemolisina e o fator necrosante citotóxico do tipo 1, sistemas de captação de ferro (aerobactina, e mecanismos de defesa do hospedeiro (cápsula ou lipopolissacarídeo são prevalentes em amostras de Escherichia coli associadas a infecções do trato urinário. O objetivo deste trabalho foi caracterizar genotipicamente 162 amostras de Escherichia coli uropatogênica (UPEC de pacientes com cistite através do ensaio da reação em cadeia da polimerase. Foram realizados três ensaios de PCR multiplex para os seguintes fatores de virulência: papC, papE/F, alelos de papG, fimH, sfa/foc, afaE, hly, cnf-1, usp, cdtB, iucD, e kpsMTII. Os resultados da PCR identificaram, 158 amostras fimH (97,5%, 86 amostras kpsMTII (53,1%, 53 amostras papC/papEF/papG (32,7%, 45 amostras sfa (27

Incidência dos genes eaeA E stx1 EM Escherichia coli isolada de carcaça suína abatida em frigoríficos comercais na região sul do Brasil

OpenAIRE

Machado, Luís Alberto Pereira

2014-01-01

A carne suína representa importante fonte de proteína animal para o mundo, porém vem sendo associada a surtos de toxinfecção alimentar. Uma das causas destes surtos é a contaminação por Escherichia coli (E. coli), encontrada no trato intestinal e ambiente dos suínos abatidos para produção de carnes in natura e industrializadas. No contexto de segurança alimentar, os surtos por Escherichia coli produtoras de toxina Shiga (STEC) são os melhores documentados. No mundo, diversos surtos causados p...

VIABILIDADE DE Escherichia coli PRODUTORA DE TOXINA SHIGA (STEC NÃO-O157 EM QUEIJO TIPO MINAS FRESCAL. VIABILITY OF NON-O157 SHIGA TOXIN-PRODUCING Escherichia coli (STEC IN MINAS FRESCAL CHEESE

Directory of Open Access Journals (Sweden)

Tammy Priscila Chioda

2009-07-01

Full Text Available Escherichia coli, produtora de toxina Shiga (STEC, um patógeno emergente capaz de causar diarreia, colite hemorrágica e síndrome hemolítica urêmica em humanos, representa um grave problema de saúde pública em todo o mundo. O principal reservatório de STEC são os bovinos. STEC são transmitidas aos humanos, principalmente através de alimentos contaminados, destacando-se aqueles de origem bovina como carne, leite e seus derivados. O objetivo deste trabalho foi avaliar a viabilidade de STEC não-O157 em queijo minas frescal preparado com leite artificialmente contaminado com diferentes cepas dessas bactérias. Os queijos foram mantidos a 4°C e analisados no 1º, 2º, 4º, 6º e 10º dias de estocagem. As cepas de STEC mantiveram-se viáveis em 100% (32/32 dos queijos mantidos sob refrigeração por até dez dias. Os resultados mostram que o queijo minas pode ser veículo de transmissão de STEC. Recomenda-se a adoção de métodos higiênicos e sanitários desde a ordenha até o processo de produção do queijo para reduzir a possibilidade de contaminação com STEC.

PALAVRAS-CHAVES: PCR, queijo minas, segurança alimentar, STEC.

Shiga toxin-producing Escherichia coli (STEC an emergent foodborne pathogen that cause diarrhea, hemorrhagic colitis and haemolytic uremic syndrome in humans, represents a public health problem all over the world. Cattle are the main source of STEC. STEC are transmitted to humans by contaminated food, mainly those of bovine origin as meat and dairy products. This study aimed evaluates the non-O157 STEC viability of artificially inoculated in the milk used for the Minas Frescal cheese’s production. The cheese was kept at 4°C and analyzed at 1st, 2nd, 4th, 6th and 10th days after its production. 100% (32/32 of the cheese storad under refrigeration during 10 days had been the STEC strains viable. These results show that minas frescal cheese can transmit STEC. The adoption of good

Effects of thermosonication on the fate of Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice.

Science.gov (United States)

Kiang, W-S; Bhat, R; Rosma, A; Cheng, L-H

2013-04-01

In this study, the effects of thermosonication and thermal treatment on Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice were investigated at 50 and 60°C. Besides, nonlethal injury of Salm. Enteritidis after both treatments was also examined. The highest inactivation was attained with thermosonication at 60°C. The inactivation rate was different for both pathogens, and Salm. Enteritidis was found to be more sensitive to thermosonication than E. coli O157:H7. Salmonella Enteritidis was recovered in all treated samples, except those subjected to more than 5-min thermosonication at 60°C. It was found that the introduction of high-intensity ultrasound enhanced the inactivation of pathogens compared to thermal treatment alone. On the other hand, Salm. Enteritidis was detected in a number of samples following incubation in universal pre-enrichment broth, but no growth was detected after incubation in mango juice. Fruit juices are commonly heat treated to inactivate micro-organisms and enzymes. However, excessive heat treatments may result in undesirable changes in juice quality. Treatment by power ultrasound, a nonthermal technology, may be an alternative processing technique to pasteurize fruit juices. This study highlights the effectiveness of thermosonication in inactivating Escherichia coli O157:H7 and Salmonella Enteritidis in mango juice. © 2012 The Society for Applied Microbiology.

Inactivation of Escherichia coli O157:H7 in vitro and on the surface of spinach leaves by biobased surfactants

Science.gov (United States)

This study was conducted to evaluate the effect of biosurfactants on the populations of Escherichia coli O157:H7 in suspension and on spinach leaves. Eight surfactants including four soybean oil-based biosurfactants, sodium dodecyl sulfate (SDS), polyoxyethylene sorbitan monooleate (Tween 80), sopho...

A longitudinal study of Escherichia coli O157 in cattle of a Dutch dairy farm and in the farm environment

NARCIS (Netherlands)

Schouten, J.M.; Graat, E.A.M.; Frankena, K.; Giessen, van de A.W.; Zwaluw, van der W.K.; Jong, de M.C.M.

2005-01-01

From July 1999 till November 2000, a longitudinal study was conducted on a dairy farm in The Netherlands to study within herd prevalence and types of verocytotoxin producing Escherichia coli (VTEC) of serogroup O157 over time, and determine environmental reservoirs and possible transmission routes.

Analysis of whole genome sequencing for the Escherichia coli O157:H7 typing phages.

Science.gov (United States)

Cowley, Lauren A; Beckett, Stephen J; Chase-Topping, Margo; Perry, Neil; Dallman, Tim J; Gally, David L; Jenkins, Claire

2015-04-08

Shiga toxin producing Escherichia coli O157 can cause severe bloody diarrhea and haemolytic uraemic syndrome. Phage typing of E. coli O157 facilitates public health surveillance and outbreak investigations, certain phage types are more likely to occupy specific niches and are associated with specific age groups and disease severity. The aim of this study was to analyse the genome sequences of 16 (fourteen T4 and two T7) E. coli O157 typing phages and to determine the genes responsible for the subtle differences in phage type profiles. The typing phages were sequenced using paired-end Illumina sequencing at The Genome Analysis Centre and the Animal Health and Veterinary Laboratories Agency and bioinformatics programs including Velvet, Brig and Easyfig were used to analyse them. A two-way Euclidian cluster analysis highlighted the associations between groups of phage types and typing phages. The analysis showed that the T7 typing phages (9 and 10) differed by only three genes and that the T4 typing phages formed three distinct groups of similar genomic sequences: Group 1 (1, 8, 11, 12 and 15, 16), Group 2 (3, 6, 7 and 13) and Group 3 (2, 4, 5 and 14). The E. coli O157 phage typing scheme exhibited a significantly modular network linked to the genetic similarity of each group showing that these groups are specialised to infect a subset of phage types. Sequencing the typing phage has enabled us to identify the variable genes within each group and to determine how this corresponds to changes in phage type.

Detection, Characterization and Typing of Shiga toxin-producing Escherichia coli.

OpenAIRE

Brendon David Parsons; Nathan eZelyas; Byron M Berenger; Linda eChui; Linda eChui

2016-01-01

Shiga toxin-producing Escherichia coli (STEC) are responsible for gastrointestinal diseases reported in numerous outbreaks around the world. Given the public health importance of STEC, effective detection, characterization and typing is critical to any medical laboratory system. While non-O157 serotypes account for the majority of STEC infections, frontline microbiology laboratories may only screen for STEC using O157-specific agar-based methods. As a result, non-O157 STEC infections are sign...

Presence of non-O157 Shiga toxin-producing Escherichia coli, enterotoxigenic E. coli, enteropathogenic E. coli and Salmonella in fresh beetroot (Beta vulgaris L.) juice from public markets in Mexico.

Science.gov (United States)

Gómez-Aldapa, Carlos A; Rangel-Vargas, Esmeralda; Bautista-De León, Haydee; Castro-Rosas, Javier

2014-10-01

Unpasteurized juice has been associated with foodborne illness outbreaks for many years. Beetroot is a vegetable grown all over the world in temperate areas. In Mexico beetroot is consumed cooked in salads or raw as fresh unpasteurized juices. No data about the microbiological quality or safety of unpasteurized beetroot juices are available. Indicator bacteria, diarrheagenic Escherichia coli pathotypes (DEP) and Salmonella frequencies were determined for fresh unpasteurized beetroot juice from restaurants. One hundred unpasteurized beetroot juice samples were collected from public markets in Pachuca, Mexico. Frequencies in these samples were 100%, 75%, 53%, 9% and 4% of positive samples, for coliform bacteria, fecal coliforms, E. coli, DEP and Salmonella, respectively. Identified DEP included enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC) and non-O157 Shiga toxin-producing E. coli (STEC). Identified Salmonella serotypes included Typhimurium and Enteritidis. This is the first report of microbiological quality and atypical EPEC, ETEC, non-O157 STEC and Salmonella isolation from fresh raw beetroot juice in Mexico. Fresh raw beetroot juice from markets is very probably an important factor contributing to the endemicity of atypical EPEC, ETEC, non-O157 STEC and Salmonella-related gastroenteritis in Mexico. © 2014 Society of Chemical Industry.

Type 1 fimbrial expression enhances Escherichia coli virulence for the urinary tract

DEFF Research Database (Denmark)

Connell, Hugh; Agace, William; Klemm, Per

1996-01-01

of Escherichia coli for the urinary tract by promoting bacterial persistence and enhancing the inflammatory responce to infection. In a clinical study, we observed that disease severity was greater in children infected with E. coli O1:K1:H7 isolates expressing type 1 fimbriae than in those infected with type 1...... negative isolates of the same serotype. The E. coli O1:K1:H7 isolates had the same electrophoretic type, were hemolysin-negative, expressed P fimbriae, and carried the fim DNA sequences. When tested in a mouse urinary tract infection model, the type 1-positive E. coli O1:K1:H7 isolates survived inhigher...... urinary tract infection model. E. coli CN1016 reconstituted with type 1 fimbriae had restored virulence similar to that of the wild-type parent strain. These results show that type 1 fimbriae in the genetic background of a uropathogenic strain contribute to the pathogenesis of E. coli in the urinary tract....

Sequential effect of phages and cold nitrogen plasma against Escherichia coli O157:H7 biofilms on different vegetables.

Science.gov (United States)

Cui, Haiying; Bai, Mei; Yuan, Lu; Surendhiran, Duraiarasan; Lin, Lin

2018-03-02

Escherichia coli O157:H7 (E. coli O157:H7) is one of the most common pathogens in fresh vegetables and fruits, and most of the diseases produced by E. coli O157:H7 are associated with biofilms. Cold nitrogen plasma (CNP) is a cold sterilization technique which has no residue. However to completely eliminate the biofilm on the surface of vegetables the processing power and time of CNP have to be enhanced, which will impact on the quality of fruits and vegetables. Thus the sequential treatment of CNP and phage techniques was engineered in this study. Compared to treatment performed separately, sequential treatment not only had more mild treatment conditions as 400W CNP treatment for 2min and 5% phage treatment for 30min, but also exhibited more remarkable effect on eradicating E. coli O157:H7 biofilms in vitro and on vegetables. The population of E. coli O157:H7 was approximately reduced by 2logCFU/cm 2 after individual treatment of 5% phages for 30min or 500W CNP for 3min. While the sequential treatment of CNP (400W, 2min) and phages (5%, 30min) reduced the E. coli O157:H7 viable count in biofilm by 5.71logCFU/cm 2 . Therefore, the sequential treatment holds a great promise to improve the current treatment systems of bacterial contamination on different vegetable surfaces. Copyright © 2018 Elsevier B.V. All rights reserved.

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

Multiplex real-time PCR assay for detection of Escherichia coli O157:H7 and screening for non-O157 Shiga toxin-producing E. coli.

Science.gov (United States)

Li, Baoguang; Liu, Huanli; Wang, Weimin

2017-11-09

Shiga toxin-producing Escherichia coli (STEC), including E. coli O157:H7, are responsible for numerous foodborne outbreaks annually worldwide. E. coli O157:H7, as well as pathogenic non-O157:H7 STECs, can cause life-threating complications, such as bloody diarrhea (hemolytic colitis) and hemolytic-uremic syndrome (HUS). Previously, we developed a real-time PCR assay to detect E. coli O157:H7 in foods by targeting a unique putative fimbriae protein Z3276. To extend the detection spectrum of the assay, we report a multiplex real-time PCR assay to specifically detect E. coli O157:H7 and screen for non-O157 STEC by targeting Z3276 and Shiga toxin genes (stx1 and stx2). Also, an internal amplification control (IAC) was incorporated into the assay to monitor the amplification efficiency. The multiplex real-time PCR assay was developed using the Life Technology ABI 7500 System platform and the standard chemistry. The optimal amplification mixture of the assay contains 12.5 μl of 2 × Universal Master Mix (Life Technology), 200 nM forward and reverse primers, appropriate concentrations of four probes [(Z3276 (80 nM), stx1 (80 nM), stx2 (20 nM), and IAC (40 nM)], 2 μl of template DNA, and water (to make up to 25 μl in total volume). The amplification conditions of the assay were set as follows: activation of TaqMan at 95 °C for 10 min, then 40 cycles of denaturation at 95 °C for 10 s and annealing/extension at 60 °C for 60 s. The multiplex assay was optimized for amplification conditions. The limit of detection (LOD) for the multiplex assay was determined to be 200 fg of bacterial DNA, which is equivalent to 40 CFU per reaction which is similar to the LOD generated in single targeted PCRs. Inclusivity and exclusivity determinants were performed with 196 bacterial strains. All E. coli O157:H7 (n = 135) were detected as positive and all STEC strains (n = 33) were positive for stx1, or stx2, or stx1 and stx2 (Table 1). No cross reactivity was detected with Salmonella

Shiga toxin-producing Escherichia coli in Central Greece: prevalence and virulence genes of O157:H7 and non-O157 in animal feces, vegetables, and humans.

Science.gov (United States)

Pinaka, O; Pournaras, S; Mouchtouri, V; Plakokefalos, E; Katsiaflaka, A; Kolokythopoulou, F; Barboutsi, E; Bitsolas, N; Hadjichristodoulou, C

2013-11-01

In Greece, Shiga toxin-producing Escherichia coli (STEC) have only been sporadically reported. The objective of this study was to estimate the prevalence of STEC and Escherichia coli O157:H7 in farm animals, vegetables, and humans in Greece. A total number of 1,010 fecal samples were collected from farm animals (sheep, goats, cattle, chickens, pigs), 667 diarrheal samples from humans, and 60 from vegetables, which were cultured in specific media for STEC isolates. Enzyme-linked immunosorbent assay (ELISA) was used to detect toxin-producing colonies, which, subsequently, were subjected to a multiplex polymerase chain reaction (PCR) for stx1, stx2, eae, rfbE O157, and fliC h7 genes. Eighty isolates (7.9 %) from animal samples were found to produce Shiga toxin by ELISA, while by PCR, O157 STEC isolates were detected from 8 (0.8 %) samples and non-O157 STEC isolates from 43 (4.2 %) samples. STEC isolates were recovered mainly from sheep and goats, rarely from cattle, and not from pigs and chickens, suggesting that small ruminants constitute a potential risk for human infections. However, only three human specimens (0.4 %) were positive for the detection of Shiga toxins and all were PCR-negative. Similarly, all 60 vegetable samples were negative for toxin production and for toxin genes, but three samples (two roman rockets and one spinach) were positive by PCR for rfbE O157 and fliC h7 genes. These findings indicate that sheep, goats, cattle, and leafy vegetables can be a reservoir of STEC and Escherichia coli O157:H7 isolates in Greece, which are still rarely detected among humans.

Fimbrial adhesins from extraintestinal Escherichia coli

DEFF Research Database (Denmark)

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

2010-01-01

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

Fitness of Enterohemorrhagic Escherichia coli (EHEC)/Enteroaggregative E. coli O104:H4 in Comparison to That of EHEC O157: Survival Studies in Food and In Vitro.

Science.gov (United States)

Böhnlein, Christina; Kabisch, Jan; Meske, Diana; Franz, Charles M A P; Pichner, Rohtraud

2016-11-01

In 2011, one of the world's largest outbreaks of hemolytic-uremic syndrome (HUS) occurred, caused by a rare Escherichia coli serotype, O104:H4, that shared the virulence profiles of Shiga toxin-producing E. coli (STEC)/enterohemorrhagic E. coli (EHEC) and enteroaggregative E. coli (EAEC). The persistence and fitness factors of the highly virulent EHEC/EAEC O104:H4 strain, grown either in food or in vitro, were compared with those of E. coli O157 outbreak-associated strains. The log reduction rates of the different EHEC strains during the maturation of fermented sausages were not significantly different. Both the O157:NM and O104:H4 serotypes could be shown by qualitative enrichment to be present after 60 days of sausage storage. Moreover, the EHEC/EAEC O104:H4 strain appeared to be more viable than E. coli O157:H7 under conditions of decreased pH and in the presence of sodium nitrite. Analysis of specific EHEC strains in experiments with an EHEC inoculation cocktail showed a dominance of EHEC/EAEC O104:H4, which could be isolated from fermented sausages for 60 days. Inhibitory activities of EHEC/EAEC O104:H4 toward several E. coli strains, including serotype O157 strains, could be determined. Our study suggests that EHEC/EAEC O104:H4 is well adapted to the multiple adverse conditions occurring in fermented raw sausages. Therefore, it is strongly recommended that STEC strain cocktails composed of several serotypes, instead of E. coli O157:H7 alone, be used in food risk assessments. The enhanced persistence of EHEC/EAEC O104:H4 as a result of its robustness, as well as the production of bacteriocins, may account for its extraordinary virulence potential. In 2011, a severe outbreak caused by an EHEC/EAEC serovar O104:H4 strain led to many HUS sequelae. In this study, the persistence of the O104:H4 strain was compared with those of other outbreak-relevant STEC strains under conditions of fermented raw sausage production. Both O157:NM and O104:H4 strains could survive

Draft genome sequences of Escherichia coli O113:H21 strains recovered from a major produce-production region in California

Science.gov (United States)

Shiga toxin-producing Escherichia coli is a foodborne and waterborne pathogen and is responsible for outbreaks of human gastroenteritis. This report documents the draft genome sequences of seven O113:H21 strains recovered from livestock, wildlife, and soil samples collected in a major agricultural r...

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

Directory of Open Access Journals (Sweden)

Alcilene de Abreu Pereira

2008-06-01

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

Comparison of the fate of the top six non-O157 shiga-toxin producing Escherichia coli (STEC) and E. coli O157:H7 during the manufacture of dry fermented sausages.

Science.gov (United States)

Balamurugan, S; Ahmed, Rafath; Gao, Anli; Strange, Phil

2017-10-16

The study examined the relative fate of the top six non-O157 shiga-toxin producing Escherichia coli (STEC) and E. coli O157:H7 during the manufacture of dry fermented sausages (DFS). Three separate batches of sausages containing a five-strain cocktail for each serogroup and uninoculated control were manufactured and subjected to identical fermentation, maturation and dry curing conditions. Changes in physicochemical properties and inoculated STEC numbers were enumerated during the DFS production stages and log reduction and log reduction rates were calculated. Inoculation of very high concentrations (8logCFUg -1 ) of STEC in the sausage batter did not significantly (P>0.05) affect the changes in the pH, a w , moisture, protein, fat content compared to the uninoculated DFS. There was a significant (P0.05) from each other. These results indicate that the lethality of DFS production processes observed against E. coli O157:H7 would result in a similar inactivation of the top six non-O157 STEC. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Complete Genome Sequence of Escherichia coli Strain WG5

DEFF Research Database (Denmark)

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

2018-01-01

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

House Flies in the Confined Cattle Environment Carry Non-O157 Shiga Toxin-Producing Escherichia coli.

Science.gov (United States)

Puri-Giri, R; Ghosh, A; Thomson, J L; Zurek, L

2017-05-01

Cattle manure is one of the primary larval developmental habitats of house flies, Musca domestica (L.). Cattle serve as asymptomatic reservoirs of Shiga toxin-producing Escherichia coli (STEC), and bacteria are released into the environment in cattle feces. The USDA-FSIS declared seven STEC serogroups (O157, O26, O45, O103, O145, O121, and O111) as adulterants in beef products. In addition, the serogroup O104 was a culprit of a large outbreak in Germany in 2011. Our study aimed to assess the prevalence of seven non-O157 STEC (O26, O45, O145, O103, O121, O111, and O104) serogroups in adult house flies. Flies (n = 463) were collected from nine feedlots and three dairy farms in six states in the United States and individually processed. This involved a culturing approach with immunomagnetic separation followed by multiplex polymerase chain reactions for detection of individual serogroups and virulence traits. The concentration of bacteria on modified Possé agar ranged between 1.0 × 101 and 7.0 × 107 (mean: 1.5 ± 0.3 × 106) CFU/fly. Out of 463 house flies, 159 (34.3%) carried one or more of six E. coli serogroups of interest. However, STEC was found in 1.5% of house flies from feedlots only. These were E. coli O103 and O104 harboring stx1 and ehxA and E. coli O45 with stx1, eae, and ehxA. This is the first study reporting the isolation of non-O157 STEC in house flies from the confined cattle environment and indicating a potential role of this insect as a vector and reservoir of non-O157 STEC in confined beef cattle. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

99mTechnetium labelled Escherichia coli

International Nuclear Information System (INIS)

Diniz, S.O.F.; Cardoso, V.N.; Resende, B.M.; Nunan, E.A.; Simal, C.J.R.

1999-01-01

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

Cross contamination of Escherichia coli O157:H7 between lettuce and wash water during home-scale washing.

Science.gov (United States)

Jensen, Dane A; Friedrich, Loretta M; Harris, Linda J; Danyluk, Michelle D; Schaffner, Donald W

2015-04-01

Lettuce and leafy greens have been implicated in multiple foodborne disease outbreaks. This study quantifies cross contamination between lettuce pieces in a small-scale home environment. A five-strain cocktail of relevant Escherichia coli O157:H7 strains was used. Bacterial transfer between single inoculated lettuce leaf pieces to 10 non-inoculated lettuce leaf pieces that were washed in a stainless steel bowl of water for 30 s, 1 min, 2 min, and 5 min was quantified. Regardless of washing time, the wash water became contaminated with 90-99% of bacteria originally present on the inoculated lettuce leaf piece. The E. coli O157:H7 concentration on initially inoculated leaf pieces was reduced ∼ 2 log CFU. Each initially uncontaminated lettuce leaf piece had ∼ 1% of the E. coli O157:H7 from the inoculated lettuce piece transferred to it after washing, with more transfer occurring during the shortest (30 s) and longest (5 min) wash times. In all cases the log percent transfer rates were essentially normally distributed. In all scenarios, most of the E. coli O157:H7 (90-99%) transferred from the inoculated lettuce pieces to the wash water. Washing with plain tap water reduces levels of E. coli O157:H7 on the inoculated lettuce leaf pieces, but also spreads contamination to previously uncontaminated leaf pieces. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

Directory of Open Access Journals (Sweden)

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.

Development of the ECODAB into a relational database for Escherichia coli O-antigens and other bacterial polysaccharides.

Science.gov (United States)

Rojas-Macias, Miguel A; Ståhle, Jonas; Lütteke, Thomas; Widmalm, Göran

2015-03-01

Escherichia coli O-antigen database (ECODAB) is a web-based application to support the collection of E. coli O-antigen structures, polymerase and flippase amino acid sequences, NMR chemical shift data of O-antigens as well as information on glycosyltransferases (GTs) involved in the assembly of O-antigen polysaccharides. The database content has been compiled from scientific literature. Furthermore, the system has evolved from being a repository to one that can be used for generating novel data on its own. GT specificity is suggested through sequence comparison with GTs whose function is known. The migration of ECODAB to a relational database has allowed the automation of all processes to update, retrieve and present information, thereby, endowing the system with greater flexibility and improved overall performance. ECODAB is freely available at http://www.casper.organ.su.se/ECODAB/. Currently, data on 169 E. coli unique O-antigen entries and 338 GTs is covered. Moreover, the scope of the database has been extended so that polysaccharide structure and related information from other bacteria subsequently can be added, for example, from Streptococcus pneumoniae. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Determining Thermal Inactivation of Escherichia coli O157:H7 in Fresh Compost by Simulating Early Phases of the Composting Process ▿

OpenAIRE

Singh, Randhir; Kim, Jinkyung; Shepherd, Marion W.; Luo, Feng; Jiang, Xiuping

2011-01-01

A three-strain mixture of Escherichia coli O157:H7 was inoculated into fresh dairy compost (ca. 107 CFU/g) with 40 or 50% moisture and was placed in an environmental chamber (ca. 70% humidity) that was programmed to ramp from room temperature to selected composting temperatures in 2 and 5 days to simulate the early composting phase. The surviving E. coli O157:H7 population was analyzed by direct plating and enrichment. Optimal and suboptimal compost mixes, with carbon/nitrogen (C/N) ratios of...

Role of major surface structures of Escherichia coli O157:H7 in initial attachment to biotic and abiotic surfaces

Science.gov (United States)

Infection by human pathogens through fresh, minimally processed produce and solid plant-derived foods is a major concern of U.S. and global food industry and public health services. The enterohemorrhagic Escherichia coli O157:H7 is a frequent and potent food borne pathogen that causes severe disease...

Antibacterial activity of selected plant essential oils against Escherichia coli O157:H7.

Science.gov (United States)

Burt, S A; Reinders, R D

2003-01-01

To quantify the antibacterial properties of five essential oils (EO) on a non-toxigenic strain of Escherichia coli O157:H7 in the presence and absence of a stabilizer and an emulsifier and at three different temperatures. Five EOs known to exhibit antibacterial properties were screened by disc diffusion assay and the most active were selected for further study in microdilution colorimetric assays. Oregano (Origanum vulgare) and thyme (Thymus vulgaris; light and red varieties) EO had the strongest bacteriostatic and bactericidal properties, followed by bay (Pimenta racemosa) and clove bud (Eugenia caryophyllata synonym: Syzygium aromaticum) EO. Oregano oil was colicidal at 625 microl l(-1) at 10, 20 and 37 degrees C. The addition of 0.05% (w/v) agar as stabilizer reinforced the antibacterial properties, particularly at 10 degrees C, whereas 0.25% (w/v) lecithin reduced antibacterial activity. Scanning electron micrographs showed extensive morphological changes to treated cells. Oregano and thyme EO possess significant in vitro colicidal and colistatic properties, which are exhibited in a broad temperature range and substantially improved by the addition of agar as stabilizer. Bay and clove bud EO are less active. Lecithin diminished antibacterial properties. The bactericidal concentration of oregano EO irreversibly damaged E. coli O157:H7 cells within 1 min. Oregano and light thyme EO, particularly when enhanced by agar stabilizer, may be effective in reducing the number or preventing the growth of E. coli O157:H7 in foods.

Estudo da Atividade Antimicrobiana das Folhas de Jatrophacurcas L. frente ao Staphylococcus aureus e Escherichia coli/ Study of Antimicrobial Activity of Leave of Jatropha curcas L. against Staphylococcus aureus and Escherichia coli

Directory of Open Access Journals (Sweden)

Amanda Venturini Arantes

2013-06-01

Full Text Available Objetivos: O presente estudo investigou a atividade antimicrobiana do extrato obtido das folhas de Jatropha curcas L., frente às bactérias Staphylococcus aureus e Escherichia coli isoladas de pacientes de um Hospital Escola do sul de Minas Gerais. Metodologia: Foi realizado o teste da Microdiluição em placas de 96 poços. Colocou-se 50µl de Ágar Mueller Hinton em todos os poços, seguidos de 50µl do extrato da planta em diferentes concentrações (25 a 200 mg/mL nas colunas apropriadas e em seguida, 10µl de cada cepa bacteriana na concentração de 0,5 de McFarland em solução salina estéril. Seguiu-se a incubação em estufa de 35ºC por 24h. Posteriormente, realizou-se a revelação pela adição de 20 µL de Cloreto de Trifenil Tetrezólico e análise dos resultados pela coloração. Em cada placa foi realizado um controle positivo e negativo. Resultados: Houve efeito inibitório do crescimento microbiano de S. aureus e E. coli perante extratos de Jatropha Curcas L. nas concentrações de 50mg a 200mg. Apenas na concentração de 25mg não houve efeito inibitório diante de E. coli e S. aureus. Conclusão: O extrato bruto de Jatropha curcas L. apresentou atividade inibitória do crescimento de colônias de Staphylococcus aureus e Escherichia coli isoladas de pacientes de um hospital escola do sul de Minas Gerais, nas concentrações 50, 75, 100, 125, 150, 175 e 200mg/ml. Objectives: This study investigated the antimicrobial activity of the extract obtained from the leaves of Jatropha curcas L., on the bacteria Staphylococcus aureus and Escherichia coli isolated from patients at a university hospital in southern Minas Gerais. Methodology: The microdilution test was made in plates of 96 wells. An amount of 50mL of Mueller Hinton agar was placed into each well, followed by 50mL of plant extract in different concentrations (25-200 mg / ml in the appropriate columns, and then 10ml of each bacterial strain at a concentration of 0.5 Mc

Meat Science and Muscle Biology Symposium: Escherichia coli O157:H7, diet, and fecal microbiome in beef cattle.

Science.gov (United States)

Wells, J E; Kim, M; Bono, J L; Kuehn, L A; Benson, A K

2014-04-01

Shiga-toxigenic Escherichia coli, such as E. coli O157:H7, are foodborne zoonotic pathogens that can cause severe illness and death in humans. The gastrointestinal tract of ruminant animals has been identified as a primary habitat for E. coli O157:H7 and, in cattle, the hindgut tract appears to be a primary site for colonization. This pathogen has been found in cattle feces, on cattle hides, and in the production environment, and transmission to humans has occurred as a result of consumption of contaminated ground beef, water, and produce. Interventions to reduce the pathogen at beef harvest have significantly reduced the occurrence of the pathogen, but outbreaks and recalls due to the pathogen still occur for beef products. Interventions in the feedyard before harvest have had little success, but critical control points for implementing interventions are limited compared with the beef abattoir. The percentage of animals shedding E. coli O157:H7 in the feces can be highly variable from pen to pen, and the levels in the feces can vary from animal to animal. Animals colonized and shedding E. coli O157:H7 at high levels are a small fraction of animals in a pen but are important source for transferring the pathogen amongst the penmates. Recent research has indicated that diet may greatly influence the shedding of E. coli O157:H7. In addition, diet can influence the microbiota composition of the feces. However, little is known about the interaction between the indigenous microbiota and fecal shedding of E. coli O157:H7. Understanding the influence of indigenous microbiota on the colonization and shedding of E. coli O157:H7 will provide a potential avenue for intervention in the preharvest production environment not yet exploited.

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.

Comparison of U.S. Environmental Protection Agency and U.S. Composting Council... Escherichia coli O157:H7 in finished compost

Science.gov (United States)

Composting management or conditions that result in inadequate exposure of the compostable materials to destructive time-temperature regimens can result in survival of enteric human pathogens. Bacterial pathogens, such as Escherichia coli O157:H7 and Salmonella spp., can regrow in finished compost. ...

A multi-pathogen selective enrichment broth for simultaneous growth of Salmonella enteria, Escherichia coli O157:H7 and Shigella flexneri

Science.gov (United States)

Salmonella, Shigella, and Escherichia coli O157:H7 contaminate similar types of food and all three can cause foodborne disease. Traditional microbiological enrichment broths to detect these pathogens are different in terms of their composition, which limits the application of multi-pathogen detectio...

Asymptomatic bacteriuria Escherichia coli strains

DEFF Research Database (Denmark)

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

2006-01-01

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

Predictors and risk factors for the intestinal shedding of Escherichia coli O157 among working donkeys (Equus asinus) in Nigeria

Science.gov (United States)

Jedial, Jesse T.; Shittu, Aminu; Tambuwal, Faruk M.; Abubakar, Mikail B.; Garba, Muhammed K.; Kwaga, Jacob P.; Fasina, Folorunso O.

2015-01-01

Objectives Escherichia coli are an important group of bacteria in the normal gastrointestinal system but can sometimes cause infections in domestic animals and man. Donkeys are routinely used as multipurpose animal but details of burdens of potentially infectious bacteria associated with it are limited. The prevalence and associations between intestinal shedding of E. coli O157 and animal characteristics and management factors were studied among 240 randomly selected working donkeys in north-western Nigeria. Design Four local government areas, of Sokoto State in north-western Nigeria were recruited in this study. A multistage randomised cluster design was used to select subjects and donkey owners within selected zones. Confirmation of infection was based on bacterial culture, isolation and biochemical test for E. coli O157 from faecal samples. Results Of the total bacteria isolated, 203 of the 329 (61.70 per cent) were E. coli, 76 of which was E. coli serotype O157. A multivariable logistic regression model was used to examine the relation between intestinal shedding of E. coli O157 and selected variables. The analysis yielded five potential predictors of shedding: soft faeces in donkeys, Akaza and Fari ecotypes of donkey were positive predictors while maize straw as feed and sampling during the cold dry period were negative predictors. Conclusions This study concludes that controlling intestinal shedding of E. coli O157 among working donkeys in Nigeria is possible using the identified predictors in planning appropriate interventions to reduced human risk of infection. PMID:26392892

Photocatalytic production of {sup 1}O{sub 2} and {center_dot}OH mediated by silver oxidation during the photoinactivation of Escherichia coli with TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Castro, Camilo A. [Centro de Investigaciones en Catalisis, Escuela de Ingenieria Quimica, Universidad Industrial de Santander (UIS), A.A. 678, Bucaramanga (Colombia); Institute of Chemical Sciences and Engineering, GGEC, Swiss Federal Institute of Technology (EPFL), Station 6, CH-1015, Lausanne (Switzerland); Osorio, Paula [Institute of Chemical Sciences and Engineering, GGEC, Swiss Federal Institute of Technology (EPFL), Station 6, CH-1015, Lausanne (Switzerland); Sienkiewicz, Andrzej [Laboratory of Complex Matter Physics, Institute of Physics of Condensed Matter, EPFL, Station 3, CH-1015, Lausanne (Switzerland); Pulgarin, Cesar, E-mail: cesar.pulgarin@epfl.ch [Institute of Chemical Sciences and Engineering, GGEC, Swiss Federal Institute of Technology (EPFL), Station 6, CH-1015, Lausanne (Switzerland); Centeno, Aristobulo [Centro de Investigaciones en Catalisis, Escuela de Ingenieria Quimica, Universidad Industrial de Santander (UIS), A.A. 678, Bucaramanga (Colombia); Giraldo, Sonia A., E-mail: sgiraldo@uis.edu.co [Centro de Investigaciones en Catalisis, Escuela de Ingenieria Quimica, Universidad Industrial de Santander (UIS), A.A. 678, Bucaramanga (Colombia)

2012-04-15

Highlights: Black-Right-Pointing-Pointer Metallic silver enhances the Ag-TiO{sub 2} photoinactivation of Escherichia coli under Vis irradiation. Black-Right-Pointing-Pointer {sup 1}O{sub 2} and {center_dot}OH were identified in Vis irradiated Ag-TiO{sub 2} suspensions. Black-Right-Pointing-Pointer UV oxidized the Ag metallic species in the material decreasing photoactivity. Black-Right-Pointing-Pointer Dark contact of the UV oxidized material with E. coli regenerates the photocatalyst. - Abstract: Ag loaded TiO{sub 2} was applied in the photocatalytic inactivation of Escherichia coli under ultraviolet (UV) and visible (Vis) light irradiations. Ag enhanced the TiO{sub 2} photodisinfecting effect under Vis irradiation promoting the formation of singlet oxygen and hydroxyl radicals as identified by EPR analyses. Ag nanoparticles, determined on TEM analyses, undergo an oxidation process on the TiO{sub 2}'s surface under UV or Vis irradiation as observed by XPS. In particular, UV pre-irradiation of the material totally diminished its photodisinfection activity under a subsequent Vis irradiation test. Under UV, photodegradation of dichloroacetic acid (DCA), attributed to photoproduced holes in TiO{sub 2}, was inhibited by the presence of Ag suggesting that oxidation of Ag{sup 0} to Ag{sup +} and Ag{sup 2+} is faster than the oxidative path of the TiO{sub 2}'s holes on DCA molecules. Furthermore, photoassisted increased of Ag{sup +} concentration on TiO{sub 2}'s surface enhances the bacteriostatic activity of the material in dark periods. Indeed, this latter dark contact of Ag{sup +}-TiO{sub 2} and E. coli seems to induce recovering of the Vis light photoactivity promoted by the surface Ag photoactive species.

Mechanosensing regulates virulence in Escherichia coli O157:H7.

Science.gov (United States)

Islam, Md Shahidul; Krachler, Anne Marie

2016-01-01

Enterohemorrhagic Escherichia coli O157:H7 is a food-borne pathogen transmitted via the fecal-oral route, and can cause bloody diarrhea and hemolytic uremic syndrome (HUS) in the human host. Although a range of colonization factors, Shiga toxins and a type III secretion system (T3SS) all contribute to disease development, the locus of enterocyte effacement (LEE) encoded T3SS is responsible for the formation of lesions in the intestinal tract. While a variety of chemical cues in the host environment are known to up-regulate LEE expression, we recently demonstrated that changes in physical forces at the site of attachment are required for localized, full induction of the system and thus spatial regulation of virulence in the intestinal tract. Here, we discuss our findings in the light of other recent studies describing mechanosensing of the host and force-dependent induction of virulence mechanisms. We discuss potential mechanisms of mechanosensing and mechanotransduction, and the level of conservation across bacterial species.

Assessment of the Contamination of Some Foodstuffs by Escherichia coli O157 in Benin, West Africa

Directory of Open Access Journals (Sweden)

Honoré Sourou Bankole

2014-01-01

Full Text Available Escherichia coli O157 is a pathogenic bacterium causing haemorrhagic colitis. It represents a serious public health problem in Northern America and Europe, which can plague Africa. Most cases of mentioned poisoning were related to contaminated meat products and vegetables. The present work aimed to estimate the prevalence of E. coli O157 in meat and vegetables in Benin. For this purpose, 6 lots of faeces samples from pigs and 8 from cattle were collected at the farms on the outskirts of Cotonou. Similarly, 20 samples of carcasses, 20 samples of intestines and stomach, and 20 surfaces samples of slaughtering equipment were taken. Vegetables and environment materials in gardens have also been sampled for 84 samples. Bacteriological analyses revealed a percentage of contamination of 50% for pig faeces and 25% for cattle ones. All the meats from stalling parks have been contaminated by this bacterium. For vegetables, 14.6% of samples were contaminated by E. coli O157. The presence of this pathovar in animal breeding and slaughtering environment and in the gardens shows that Benin is not aware of the risks of foodborne illness associated with the consumption of contaminated products. Therefore, it urges including that germ in a systematic search during safety control of food products in Benin.

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

NARCIS (Netherlands)

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

2016-01-01

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

Assessment of Salmonella spp. and Escherichia coli O157:H7 growth on lettuce exposed to isothermal and non-isothermal conditions.

Science.gov (United States)

de Oliveira Elias, Susana; Noronha, Tiago Baptista; Tondo, Eduardo Cesar

2018-06-01

This study aimed to assess the growth of Salmonella and Escherichia coli O157:H7 on lettuce exposed to isothermal and non-isothermal conditions. Pathogens were inoculated on lettuce separately and stored under isothermal condition at 5 °C, 10 °C, 25 °C, 37 °C for both bacteria, at 40 °C for Salmonella and 42 °C for E. coli O157:H7. Growth curves were built by fitting the data to the Baranyi's DMFit, generating R 2 values greater than 0.92 for primary models. Secondary models were fitted with Ratkowsky equations, generating R 2 values higher than 0.91 and RMSE lower than 0.1. Experimental data showed that both bacteria could grow at all temperatures. Also, the growth of both pathogens under non-isothermal conditions was studied simulating temperatures found from harvest to supermarkets in Brazil. Models were analysed by R 2 , RMSE, bias factor (Bf) and accuracy factor (Af). Salmonella and E. coli O157:H7 were able to grow in this temperature profile and the models could predict the behavior of these microorganisms on lettuce under isothermal and non-isothermal conditions. Based on the results, a negligible growth time (ς) was proposed to provide the time which lettuce could be exposed to a specific temperature and do not present an expressive growth of bacteria. The ς was developed based on Baranyi's primary model equation and on growth potential concept. ς is the value of lag phase added of the time necessary to population grow 0.5 log CFU/g. The ς of lettuce exposed to 37 °C was 1.3 h, while at 5 °C was 3.3 days. Copyright © 2017 Elsevier Ltd. All rights reserved.

PCR and ELISA (VIDAS ECO O157® Escherichia coli O157:H7 identification in Minas Frescal cheese commercialized in Goiânia, GO

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Rosangela Nunes Carvalho

2014-01-01

Full Text Available Escherichia coli O157:H7 has been incriminated in food poisoning outbreaks and sporadic cases of hemorrhagic colitis and hemolytic uremic syndrome in many countries. Considering the high susceptibility of Minas Frescal cheese to contamination by E. coli O157:H7, the aim of this study was to determine the occurrence of this pathogen through PCR (Polymerase Chain Reaction and ELISA (VIDAS ECO O157®, bioMérieux, Lyon, France test. Thirty cheese samples manufactured by artisan farmhouse producers were collected from open-air markets in Goiânia and thirty from industries under Federal Inspection located in Goiás State which trade their products in supermarkets in Goiânia. E. coli O157:H7 was detected in 6.67% samples collected in open air markets using ELISA, and 23,33% with PCR. The pathogen was not detected in samples from industries under Federal Inspection.

PCR and ELISA (VIDAS ECO O157®) Escherichia coli O157:H7 identification in Minas Frescal cheese commercialized in Goiânia, GO

Science.gov (United States)

Carvalho, Rosangela Nunes; de Oliveira, Antonio Nonato; de Mesquita, Albenones José; Minafra e Rezende, Cíntia Silva; de Mesquita, Adriano Queiroz; Romero, Rolando Alfredo Mazzoni

2014-01-01

Escherichia coli O157:H7 has been incriminated in food poisoning outbreaks and sporadic cases of hemorrhagic colitis and hemolytic uremic syndrome in many countries. Considering the high susceptibility of Minas Frescal cheese to contamination by E. coli O157:H7, the aim of this study was to determine the occurrence of this pathogen through PCR (Polymerase Chain Reaction) and ELISA (VIDAS ECO O157®, bioMérieux, Lyon, France) test. Thirty cheese samples manufactured by artisan farmhouse producers were collected from open-air markets in Goiânia and thirty from industries under Federal Inspection located in Goiás State which trade their products in supermarkets in Goiânia. E. coli O157:H7 was detected in 6.67% samples collected in open air markets using ELISA, and 23,33% with PCR. The pathogen was not detected in samples from industries under Federal Inspection. PMID:24948907

Escherichia coli O157:H7- patógeno alimentar emergente / Escherichia coli O157:H7 - emerging food pathogen

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Cheila Minéia Daniel de Paula

2014-11-01

Full Text Available Segundo a Organização Mundial da Saúde, cerca de 2,2 milhões de pessoas morrem anualmente em função de doenças hídricas ou alimentares, a maioria dos quais são crianças. Estas doenças são causadas por patógenos já conhecidos, emergentes ou reemergentes, principalmente bactérias. A globalização tem contribuído na disseminação de patógenos de origem alimentar, aumentando o desafio relacionado à identificação da origem desses agentes e à elaboração de regulamentação e fiscalização adequadas. O cenário das Doenças Transmitidas por Alimentos (DTA muda constantemente e a prevalência de determinada doença varia de época para época, assim como os agentes etiológicos destas. Dentre os principais patógenos emergentes em nível mundial, E. coli O157:H7 tem ganhado grande destaque nos últimos 20 anos, devido à severidade de seus surtos. Até pouco tempo, o Brasil era considerado livre desse patógeno, porém a bibliografia científica e registros epidemiológicos demonstram o contrário. Em vista disso, o presente artigo objetiva realizar uma revisão integrativa da literatura, enfocando as características, os métodos de isolamento e detecção e os dados epidemiológicos da E. coli O157:H7 no Brasil e no mundo. =============================================== According to the World Health Organization, about 2.2 million people, most of whom are children, die each year due to water and foodborne illnesses. These illnesses are caused by known, emerging, or reemerging pathogens, mainly bacteria. Globalization has contributed to the spread of foodborne pathogens, increasing the challenge of identifying the origin of these agents and of developing appropriate regulation and monitoring. The scenario of Foodborne Illnesses (FI constantly changes and the prevalence of a particular illnesses as well as its etiological agents, vary from season to season. Among the major emerging pathogens at a global level, E. coli O157:H7

Sterilization of Escherichia coli by using near-UV LED and TiO{sub 2} nanofibers that were prepared by using electrostatic spray

Energy Technology Data Exchange (ETDEWEB)

Lee, Dong-Gil; Hong, Ji-Tae; Son, Min-Kyu; Lee, Kyoung-Jun; Xu, Guo-Cheng; Prabakar, Kandasamy; Kim, Hee-je, E-mail: heeje@pusan.ac.k [Department of Electrical Engineering Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of)

2010-05-01

TiO{sub 2} nanofiber films were prepared by a homemade electrostatic spray method at 13 kV using a high power supply. As-prepared TiO{sub 2} was used to sterilize enteropathogenic Escherichia coli in polluted water by using near-UV LEDs at three different wavelengths with variable exposure time and frequency of irradiation. Irrespective of the wavelength of the light source used, longer irradiation times such as 1 h completely inactivated the E. coli. However, a wavelength of 375 nm was effective in inactivating in a shorter irradiation time (15 min). When the frequency of irradiation was 1 kHz, almost 95% of the E. coli was inactivated after 30 min exposure.

Inactivation of shiga toxin-producing Escherichia coli in lean ground beef by gamma irradiation

Science.gov (United States)

Non-O157 serovars of Shiga Toxin-producing Escherichia coli (STEC) are now responsible for over 60% of STEC induced illnesses. The majority of illnesses caused by non-O157:H7 STEC have been due to serogroups O26, O121, O103, O45, O111, and O145, “the big/top six”, which are now considered adulterant...

Characterization of Escherichia coli Phylogenetic Groups ...

African Journals Online (AJOL)

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

WGS accurately predicts antimicrobial resistance in Escherichia coli

Science.gov (United States)

Objectives: To determine the effectiveness of whole-genome sequencing (WGS) in identifying resistance genotypes of multidrug-resistant Escherichia coli (E. coli) and whether these correlate with observed phenotypes. Methods: Seventy-six E. coli strains were isolated from farm cattle and measured f...

Antimicrobial activity of some of the south-Indian spices against serotypes of Escherichia coli, Salmonella, Listeria monocytogenes and Aeromonas hydrophila Atividade antimicrobiana de condimentos do sul da India sobre Escherichia coli, Salmonella, Listeria monocytogenes e Aeromonas hydrophila

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M.N. Indu

2006-06-01

Full Text Available Antibacterial activity of extracts of Allium sativum (garlic, Myristica fragrans (nutmeg, Zingiber officinale (ginger, Allium cepa (onion and Piper nigrum (pepper has been evaluated against 20 different serogroups of Escherichia coli, 8 serotypes of Salmonella, Listeria monocytogenes and Aeromonas hydrophila. Garlic extract showed excellent antibacterial activity against all the test organisms, except L. monocytogenes. Nutmeg showed good anti-listerial activity, although activity against E. coli and Salmonella were serotype dependent. Both garlic and nutmeg extracts were effective against A. hydrophila. Extracts of ginger showed inhibitory activity against two serogroups of E. coli: as O8 (enterotoxigenic E. coli and O88 only. Extracts of onion and pepper did not show any antibacterial activity against the test organisms.Avaliou-se a atividade antimicrobiana de extratos de alho (Allium sativum, noz-moscada (Mysritica frangrans, gengibre (Zingiber officinale cebola (Allium cepa e pimenta do reino (Piper nigrum sobre 20 sorotipos de Escherichia coli, 8 sorotipos de Salmonella, Listeria monocytogenes e Aeromonas hydrophila. O alho apresentou atividade antimicrobiana excelente sobre todos os microrganismos testados, excepto L. monocytogenes. A noz-moscada apresentou boa atividade antilisteria, emboara atividade sobre E. coli e Salmonella tenha sido sorotipo-dependente. Tanto alho como noz-moscada foram eficientes contra A. hydrophila. O extrato de gengibre apresentou atividade inibitória sobre dois sorotipos de E. coli: 08 (enterotoxigenico e 088. Os extratos de cebola e pimenta do reino não apresentaram nenhuma atividade contra os microrganismos testados.

Investigation of Combination Effect of Magnesium Oxide and Iron Oxide Nanoparticles on the Growth And Morphology of the Bacteria Staphylococcus Aureus and Escherichia Coli in Juice

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mahdi torabi zarchi

2017-02-01

Full Text Available Introduction: Nanoparticles (NPs are one of the antibacterial substances, among them nanoparticles type MgO and Fe2O3 are less toxic to mammalian cells. So, the aim of this study was investigation of combination effects of iron oxide and magnesium oxide nanoparticles on the growth of Staphylococcus aureus and Escherichia coli (E.coli to achieve the optimum combination of nanoparticles inhibit the growth of Staphylococcus aureus and Escherichia coli in food (juice. Methods: In this experimental research, the effect of MgO and Fe2O3 Nanoparticles compound on Staphylococcus aureus and Escherichia coli bacteria in liquid environment was investigated, and then their effect was investigated separately in juices of carrot, pomegranate and apple via colony count approach. Also, scanning electron microscopy was used to characterize the morphological changes of Staphylococcus aureus and Escherichia coli after antimicrobial treatments. The results of the research were analyzed using one way ANNOVA. Results: The results of the research indicated that in liquid medium, these nanoparticles lead to reduce the growth of both bacteria. compound of 1.5Mg+0.5Fe2O3 was introduced as the most appropriate antibacterial compounds; Staphylococcus aureus sensitivity to Escherichia coli was higher against nanoparticles. The findings of research about the juices revealed that the combined effect of nanoparticles reduced the growth of both bacteria. the combined effect of Fe2o3 and MgO nanoparticles treatments distorted and damaged the cell membrane, resulting in a leakage of intracellular contents and eventually the death of bacterial cells. Conclusion: Nanoparticles in the allowed concentrations have significant effect on Staphylococcus aureus and Escherichia coli bacteria.

Detection and characterization of verocytotoxin-producing Escherichia coli by automated 5 ' nuclease PCR assay

DEFF Research Database (Denmark)

Nielsen, Eva Møller; Andersen, Marianne Thorup

2003-01-01

In recent years increased attention has been focused on infections caused by isolates of verocytotoxin-producing Escherichia coli (VTEC) serotypes other than O157. These non-O157 VTEC isolates are commonly present in food and food production animals. Easy detection, isolation, and characterizatio...

Transport of Escherichia coli phage through saturated porous media considering managed aquifer recharge.

Science.gov (United States)

Zhang, Wenjing; Li, Shuo; Wang, Shuang; Lei, Liancheng; Yu, Xipeng; Ma, Tianyi

2018-03-01

Virus is one of the most potentially harmful microorganisms in groundwater. In this paper, the effects of hydrodynamic and hydrogeochemical conditions on the transportation of the colloidal virus considering managed aquifer recharge were systematically investigated. Escherichia coli phage, vB_EcoM-ep3, has a broad host range and was able to lyse pathogenic Escherichia coli. Bacteriophage with low risk to infect human has been found extensively in the groundwater environment, so it is considered as a representative model of groundwater viruses. Laboratory studies were carried out to analyze the transport of the Escherichia coli phage under varying conditions of pH, ionic strength, cation valence, flow rate, porous media, and phosphate buffer concentration. The results indicated that decreasing the pH will increase the adsorption of Escherichia coli phage. Increasing the ionic strength, either Na + or Ca 2+ , will form negative condition for the migration of Escherichia coli phage. A comparison of different cation valence tests indicated that changes in transport and deposition were more pronounced with divalent Ca 2+ than monovalent Na + . As the flow rate increases, the release of Escherichia coli phage increases and the retention of Escherichia coli phage in the aquifer medium reduces. Changes in porous media had a significant effect on Escherichia coli phage migration. With increase of phosphate buffer concentration, the suspension stability and migration ability of Escherichia coli phage are both increased. Based on laboratory-scale column experiments, a one-dimensional transport model was established to quantitatively describe the virus transport in saturated porous medium.

ELECTROPHORETIC MOBILITIES OF ESCHERICHIA COLI 0157:H7 AND WILD-TYPE ESCHERICHIA COLI STRAINS

Science.gov (United States)

The electrophoretic mobility (EPM) of a number of human-virulent and "wild-type" Escherichia coli strains in phosphate buffered water was measured. The impact of pH, ionic strength, cation type (valence) and concentration, and bacterial strain on the EPM was investigated. Resul...

Escherichia coli survival in waters: Temperature dependence

Science.gov (United States)

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

Lethality Prediction for Escherichia Coli O157:H7 and Uropathogenic E. coli in Ground Chicken Treated with High Pressure Processing and Trans-Cinnamaldehyde.

Science.gov (United States)

Sheen, Shiowshuh; Huang, Chi-Yun; Ramos, Rommel; Chien, Shih-Yung; Scullen, O Joseph; Sommers, Christopher

2018-03-01

Pathogenic Escherichia coli, intestinal (O157:H7) as well as extraintestinal types (for example, Uropathogenic E. coli [UPEC]) are commonly found in many foods including raw chicken meat. The resistance of E. coli O157:H7 to UPEC in chicken meat under the stresses of high hydrostatic Pressure (HHP, also known as HPP-high pressure processing) and trans-cinnamaldehyde (an essential oil) was investigated and compared. UPEC was found slightly less resistant than O157:H7 in our test parameter ranges. With the addition of trans-cinnamaldehyde as an antimicrobial to meat, HPP lethality enhanced both O157:H7 and UPEC inactivation. To facilitate the predictive model development, a central composite design (CCD) was used to assess the 3-parameter effects, that is, pressure (300 to 400 MPa), trans-cinnamaldehyde dose (0.2 to 0.5%, w/w), and pressure-holding time (15 to 25 min), on the inactivation of E. coli O157:H7 and UPEC in ground chicken. Linear models were developed to estimate the lethality of E. coli O157:H7 (R 2 = 0.86) and UPEC (R 2 = 0.85), as well as dimensionless nonlinear models. All models were validated with data obtained from separated CCD combinations. Because linear models of O157:H7 and UPEC had similar R 2 and the significant lethality difference of CCD points was only 9 in 20; all data were combined to generate models to include both O157:H7 and UPEC. The results provide useful information/tool to predict how pathogenic E. coli may survive HPP in the presence of trans-cinnamaldehyde and to achieve a great than 5 log CFU/g reduction in chicken meat. The models may be used for process optimization, product development and to assist the microbial risk assessment. The study provided an effective means to reduce the high hydrostatic pressure level with incorporation of antimicrobial compound to achieve a 5-log reduction of pathogenic E. coli without damaging the raw meat quality. The developed models may be used to predict the high pressure processing

Foodborne transmission of sorbitol-fermenting Escherichia coli O157:[H7] via ground beef: an outbreak in northern France, 2011.

Science.gov (United States)

King, L A; Loukiadis, E; Mariani-Kurkdjian, P; Haeghebaert, S; Weill, F-X; Baliere, C; Ganet, S; Gouali, M; Vaillant, V; Pihier, N; Callon, H; Novo, R; Gaillot, O; Thevenot-Sergentet, D; Bingen, E; Chaud, P; de Valk, H

2014-12-01

Sorbitol-fermenting Escherichia coli O157:[H7] is a particularly virulent clone of E. coli O157:H7 associated with a higher incidence of haemolytic uraemic syndrome and a higher case fatality rate. Many fundamental aspects of its epidemiology remain to be elucidated, including its reservoir and transmission routes and vehicles. We describe an outbreak of sorbitol-fermenting E. coli O157:[H7] that occurred in France in 2011. Eighteen cases of paediatric haemolytic uraemic syndrome with symptom onset between 6 June and 15 July 2011 were identified among children aged 6 months to 10 years residing in northern France. A strain of sorbitol-fermenting E. coli O157:[H7] stx2a eae was isolated from ten cases. Epidemiological, microbiological and trace-back investigations identified multiply-contaminated frozen ground beef products bought in a supermarket chain as the outbreak vehicle. Strains with three distinct pulsotypes that were isolated from patients, ground beef preparations recovered from patients' freezers and from stored production samples taken at the production plant were indistinguishable upon molecular comparison. This investigation documents microbiologically confirmed foodborne transmission of sorbitol-fermenting of E. coli O157 via beef and could additionally provide evidence of a reservoir in cattle for this pathogen. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

Prevalence of diarrheogenic Escherichia coli and rotavirus among children from Botucatu, São Paulo State, Brazil

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Rodrigues J.

2002-01-01

Full Text Available In a one-year prospective study carried out to define the role of rotavirus and Escherichia coli in local childhood diarrhea, we determined the prevalence of both agents in 54 diarrheic children attending a health center in Botucatu. Diarrheogenic E. coli (DEC strains were characterized by O:H serotyping, a search for virulence genetic markers, and assays of adherence to HEp-2 cells. Except for enteroaggregative E. coli (EAEC, no other DEC category was detected in the children's stools. Both EAEC and rotavirus were isolated from 22 of the 54 (41.0% diarrheic children as single agents or in combination with other enteropathogens. However, when considering the presence of a single agent, EAEC was dominant and isolated from 20.4% of the patients, whereas rotavirus was detected in 14.8%. These results indicate that rotavirus and EAEC play a significant role as agents of childhood diarrhea in the local population.

Immunologic Control of Diarrheal Disease Due to Enterotoxigenic Escherichia coli: Reactogenicity, Immunogenicity, and Efficacy Studies of Pili Vaccines

Science.gov (United States)

1981-09-01

bacterial hemagglutination teLhnique for detection of Shigella antibodies. J. Bacteriol. 91:463, 1966. -25- Appendix A 20. Levine, M.M. Legai and ethical...Gotschlich. E.C. Type 1 Escherichia coli pill: characterization of binding to monkey kidney cells. J. Exp. Med. 146:1132, 1977. 40. Santini, R., Jr., Sheehy

Resistência a antimicrobianos dependente do sistema de efluxo multidrogas em Escherichia coli isoladas de leite mastítico Antimicrobial resistance dependent on multidrugs efflux in Escherichia coli isolated from the mastitic milk

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M.A.S. Moreira

2008-12-01

Full Text Available Identificaram-se e caracterizaram-se a resistência e a multirresistência aos principais antimicrobianos usados no tratamento de mastite bovina causada por Escherichia coli. A concentração inibitória mínima (MIC e o sistema de efluxo foram detectados pelas curvas de crescimento, com base na densidade óptica, em diferentes concentrações da droga e na presença e na ausência do desacoplador da força próton-motora (PMF. E. coli 1 foi resistente à neomicina e à gentamicina; E. coli 3 e 4, à tetraciclina e à estreptomicina; e E. coli 2 e 6 à gentamicina. E. coli 5 apresentou modelo de sensibilidade. Observou-se que MICs de todos os antimicrobianos dos multirresistentes (E. coli 1, 3 e 4 diminuíram na presença do desacoplador, o que sugere sistema de efluxo multidrogas. Após cura, apenas E. coli 1 apresentou modelo de sensibilidade, porém não houve alterações das MICs, antes e após adição do desacoplador. Os resultados indicam possível presença de mecanismo de resistência dependente da PMF codificado, ou parte dele, em plasmídeo.Resistance and multiresistance to main antimicrobials used for treating bovine mastitis caused by Escherichia coli were identified and characterized. The minimal inhibitory concentration (MIC and efflux systems were detected by the use of growth curves based on optical density at different drug concentrations and both presence and absence of uncoupler of the proton-motive force (PMF. E. coli 1 was resistant to neomycin and gentamycin, E. coli 3 and 4 were resistant to tetracycline and streptomycin, whereas E. coli 2 and 6 were resistant to gentamycin. E. coli 5 showed sensibility model. MICs of all antimicrobials of the multiresistant samples (E. coli 1, 3, and 4 were decreased in presence of the uncoupler, therefore suggesting the presence of the multidrug efflux system. After healing, only E. coli 1 showed sensibility model, however no alteration occurred in MIC(s before and after adding the

Genomic epidemiology of the Escherichia coli O104:H4 outbreaks in Europe, 2011

DEFF Research Database (Denmark)

Grad, Yonatan H; Lipsitch, Marc; Feldgarden, Michael

2012-01-01

The degree to which molecular epidemiology reveals information about the sources and transmission patterns of an outbreak depends on the resolution of the technology used and the samples studied. Isolates of Escherichia coli O104:H4 from the outbreak centered in Germany in May-July 2011, and the ...... that purged diversity in the German isolates, variation in mutation rates in the two E. coli outbreak populations, or uneven distribution of diversity in the seed populations that led to each outbreak....... remarkably little diversity, with only two single nucleotide polymorphisms (SNPs) found in isolates from four individuals. Surprisingly, we found much greater diversity (19 SNPs) in isolates from seven individuals infected in the French outbreak. The German isolates form a clade within the more diverse...... French outbreak strains. Moreover, five isolates derived from a single infected individual from the French outbreak had extremely limited diversity. The striking difference in diversity between the German and French outbreak samples is consistent with several hypotheses, including a bottleneck...

Detection of viable Escherichia coli O157:H7 in ground beef by propidium monoazide real-time PCR.

Science.gov (United States)

Liu, Yarui; Mustapha, Azlin

2014-01-17

Escherichia coli O157:H7 associated with food has caused many serious public health problems in recent years. However, only viable cells of this pathogen can cause infections, and false-positive detection caused by dead cells can lead to unnecessary product recalls. The objective of this study was to develop and optimize a method that combines propidium monoazide (PMA) staining with real-time PCR to detect only viable cells of E. coli O157:H7 in ground beef. PMA is a DNA intercalating dye that can penetrate compromised membranes of dead cells and bind to cellular DNA, preventing its amplification via a subsequent PCR. Three strains of E. coli O157:H7 (505B, G5310 and C7927) at concentrations of 10(0) to 10(8)CFU/mL were used as live cells. Dead cells were obtained by heating cell suspensions at 85°C for 15 min. Suspensions were treated with PMA and the optimized assay was applied to artificially contaminated ground beef with two different fat contents (10% and 27%). DNA was extracted and amplified by TaqMan® real-time PCR assay targeting the uidA gene for detection of E. coli O157:H7. Plasmid pUC19 was added as an internal amplification control (IAC). A treatment of 25 μM PMA with a 10-min light exposure on ice was sufficient to eliminate DNA from 10(8) dead E. coli O157:H7 cells/mL. The optimized assay could detect as low as 10(2) CFU/mL viable E. coli O157:H7 in pure culture and 10(5) CFU/g in ground beef, in the presence of 10(6)/mL or g of dead cells. With an 8-h enrichment, 1 CFU/g viable E. coli O157:H7 in ground beef was detectable without interference from 10(6) dead cells/g. In conclusion, the PMA real-time PCR could effectively detect viable E. coli O157:H7 without being compromised by dead cells. Copyright © 2013 Elsevier B.V. All rights reserved.

Tipagem molecular e resistência aos antimicrobianos em isolados de Escherichia coli de frangos de corte e de tratadores na Região Metropolitana de Curitiba, Paraná

OpenAIRE

Korb, Arnildo; Nazareno, Eleusis R. de; Costa, Libera D.; Nogueira, Keite da Silva; Dalsenter, Paulo R.; Tuon, Felipe F.B.; Pomba, Maria C.

2015-01-01

Este estudo verificou o perfil de resistência aos antimicrobianos entre isolados de Escherichia coli de frangos de corte de criação intensiva e de subsistência e dos respectivos tratadores e a similaridade genotípica entre isolados de E.coli de frangos de corte de criação intensiva e isolados de E. coli de tratadores de frangos de criação intensiva pela técnica de Eletroforese em Gel de Campo Pulsado (PFGE). 60 amostras de fezes de frangos de criação intensiva, 60 de frangos de corte de criaç...

Repetitive Immunosensor with a Fiber-Optic Device and Antibody-Coated Magnetic Beads for Semi-Continuous Monitoring of Escherichia coli O157:H7.

Science.gov (United States)

Taniguchi, Midori; Saito, Hirokazu; Mitsubayashi, Kohji

2017-09-19

A rapid and reproducible fiber-optic immunosensor for Escherichia coli O157:H7 ( E. coli O157:H7) was described. The biosensor consisted of a flow cell, an optical fiber with a thin Ni layer, and a PC linked fluorometer. First, the samples with E. coli O157:H7 were incubated with magnetic beads coated with anti- E. coli O157:H7 antibodies and anti- E. coli O157:H7 antibodies labeled cyanine 5 (Cy5) to make sandwich complexes. Then the Cy5-( E. coli O157:H7)-beads were injected into a flow cell and pulled to the magnetized Ni layer on the optical fiber set in the flow cell. An excitation light (λ = 635 nm) was used to illuminate the optical fiber, and the Cy5 florescent molecules facing the optical fiber were exposed to an evanescent wave from the optical fiber. The 670 nm fluorescent light was measured using a photodiode. Finally, the magnetic intensity of the Ni layer was removed and the Cy5- E. coli O157:H7-beads were washed out for the next immunoassay. E. coli O157:H7, diluted with phosphate buffer (PB), was measured from 1 × 10⁵ to 1 × 10⁷ cells/mL. The total time required for an assay was less than 15 min (except for the pretreatment process) and repeating immunoassay on one optical fiber was made possible.

Inactivation of Nonpathogenic Escherichia coli, Escherichia coli O157:H7, Salmonella enterica Typhimurium, and Listeria monocytogenes in Ice Using a UVC Light-Emitting Diode.

Science.gov (United States)

Murashita, Suguru; Kawamura, Shuso; Koseki, Shigenobu

2017-07-01

Ice, widely used in the food industry, is a potential cause of food poisoning resulting from microbial contamination. Direct microbial inactivation of ice is necessary because microorganisms may have been present in the source water used to make it and/or may have been introduced due to poor hygiene during production or handling of the ice. Nonthermal and nondestructive microbial inactivation technologies are needed to control microorganisms in ice. We evaluated the applicability of a UVC light-emitting diode (UVC-LED) for microbial inactivation in ice. The effects of UV intensity and UV dose of the UVC-LED on Escherichia coli ATCC 25922 and a comparison of UVC-LED with a conventional UV lamp for effective bacterial inactivation in distilled water and ice cubes were investigated to evaluate the performance of the UVC-LED. Finally, we assessed the effects of the UVC-LED on pathogens such as E. coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in ice cubes. The results indicated that UVC-LED effectiveness depended on the UV dose at all UV intensity conditions (0.084, 0.025, 0.013, 0.007, and 0.005 mW/cm 2 ) in ice and that UVC-LED could more efficiently inactivate E. coli ATCC 25922 in distilled water and ice than the UV lamp. At a UV dose of 2.64 mJ/cm 2 , E. coli in distilled water was decreased by 0.90 log CFU/mL (UV lamp) and by more than 7.0 log CFU/mL (UVC-LED). At 15.2 mJ/cm 2 , E. coli in ice was decreased by 3.18 log CFU/mL (UV lamp) and by 4.45 CFU/mL (UVC-LED). Furthermore, UVC-LED irradiation reduced the viable number of pathogens by 6 to 7 log cycles at 160 mJ/cm 2 , although the bactericidal effect was somewhat dependent on the type of bacteria. L. monocytogenes in ice was relatively more sensitive to UVC irradiation than were E. coli O157:H7 and Salmonella Typhimurium. These results demonstrate that UVC-LED irradiation could contribute to the safety of ice in the food industry.

Comparison of 61 Sequenced Escherichia coli Genomes

DEFF Research Database (Denmark)

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

2010-01-01

Escherichia coli is an important component of the biosphere and is an ideal model for studies of processes involved in bacterial genome evolution. Sixty-one publically available E. coli and Shigella spp. sequenced genomes are compared, using basic methods to produce phylogenetic and proteomics...

lactamase in clinical isolates of Escherichia coli

African Journals Online (AJOL)

Jane

2011-08-22

Aug 22, 2011 ... The beta lactamase enzyme producing E. coli, resistant to β-lactam antibiotics, created many problems ... Key words: Escherichia coli, β-lactamase enzymes, TEM-type extended spectrum ... difficulties in treatment using antibiotics that are currently ... and chloramphenicol (30 µg) (Mast Diagnostics Ltd., UK).

Restricted diffusion of DNA segments within the isolated Escherichia coli nucleoid.

NARCIS (Netherlands)

Cunha, S.; Woldringh, C.L.; Odijk, T.

2005-01-01

To study the dynamics and organization of the DNA within isolated Escherichia coli nucleoids, we track the movement of a specific DNA region. Labeling of such a region is achieved using the Lac-O/Lac-I system. The Lac repressor-GFP fusion protein binds to the DNA section where tandem repeats of the

Assessment of Shiga toxin-producing Escherichia coli isolates from wildlife meat as potential pathogens for humans.

Science.gov (United States)

Miko, Angelika; Pries, Karin; Haby, Sabine; Steege, Katja; Albrecht, Nadine; Krause, Gladys; Beutin, Lothar

2009-10-01

A total of 140 Shiga toxin-producing Escherichia coli (STEC) strains from wildlife meat (deer, wild boar, and hare) isolated in Germany between 1998 and 2006 were characterized with respect to their serotypes and virulence markers associated with human pathogenicity. The strains grouped into 38 serotypes, but eight O groups (21, 146, 128, 113, 22, 88, 6, and 91) and four H types (21, 28, 2, and 8) accounted for 71.4% and 75.7% of all STEC strains from game, respectively. Eighteen of the serotypes, including enterohemorrhagic E. coli (EHEC) O26:[H11] and O103:H2, were previously found to be associated with human illness. Genes linked to high-level virulence for humans (stx(2), stx(2d), and eae) were present in 46 (32.8%) STEC strains from game. Fifty-four STEC isolates from game belonged to serotypes which are frequently found in human patients (O103:H2, O26:H11, O113:H21, O91:H21, O128:H2, O146:H21, and O146:H28). These 54 STEC isolates were compared with 101 STEC isolates belonging to the same serotypes isolated from farm animals, from their food products, and from human patients. Within a given serotype, most STEC strains were similar with respect to their stx genotypes and other virulence attributes, regardless of origin. The 155 STEC strains were analyzed for genetic similarity by XbaI pulsed-field gel electrophoresis. O103:H2, O26:H11, O113:H21, O128:H2, and O146:H28 STEC isolates from game were 85 to 100% similar to STEC isolates of the same strains from human patients. By multilocus sequence typing, game EHEC O103:H2 strains were attributed to a clonal lineage associated with hemorrhagic diseases in humans. The results from our study indicate that game animals represent a reservoir for and a potential source of human pathogenic STEC and EHEC strains.

Assessment of Shiga Toxin-Producing Escherichia coli Isolates from Wildlife Meat as Potential Pathogens for Humans▿

Science.gov (United States)

Miko, Angelika; Pries, Karin; Haby, Sabine; Steege, Katja; Albrecht, Nadine; Krause, Gladys; Beutin, Lothar

2009-01-01

A total of 140 Shiga toxin-producing Escherichia coli (STEC) strains from wildlife meat (deer, wild boar, and hare) isolated in Germany between 1998 and 2006 were characterized with respect to their serotypes and virulence markers associated with human pathogenicity. The strains grouped into 38 serotypes, but eight O groups (21, 146, 128, 113, 22, 88, 6, and 91) and four H types (21, 28, 2, and 8) accounted for 71.4% and 75.7% of all STEC strains from game, respectively. Eighteen of the serotypes, including enterohemorrhagic E. coli (EHEC) O26:[H11] and O103:H2, were previously found to be associated with human illness. Genes linked to high-level virulence for humans (stx2, stx2d, and eae) were present in 46 (32.8%) STEC strains from game. Fifty-four STEC isolates from game belonged to serotypes which are frequently found in human patients (O103:H2, O26:H11, O113:H21, O91:H21, O128:H2, O146:H21, and O146:H28). These 54 STEC isolates were compared with 101 STEC isolates belonging to the same serotypes isolated from farm animals, from their food products, and from human patients. Within a given serotype, most STEC strains were similar with respect to their stx genotypes and other virulence attributes, regardless of origin. The 155 STEC strains were analyzed for genetic similarity by XbaI pulsed-field gel electrophoresis. O103:H2, O26:H11, O113:H21, O128:H2, and O146:H28 STEC isolates from game were 85 to 100% similar to STEC isolates of the same strains from human patients. By multilocus sequence typing, game EHEC O103:H2 strains were attributed to a clonal lineage associated with hemorrhagic diseases in humans. The results from our study indicate that game animals represent a reservoir for and a potential source of human pathogenic STEC and EHEC strains. PMID:19700552

Leakage of Intracellular UV Materials of High Hydrostatic Pressure-Injured Escherichia Coli O157:H7 Strains in Tomato Juice

Science.gov (United States)

The effect of high hydrostatic pressure (HHP) treatment on inactivation, injury and recovery of Salmonella Enteritidis and Escherichia coli O157:H7 cocktail inoculated in tomato juice (pH 4.1) and phosphate buffer saline (PBS. pH 7.2) at 8.0 log CFU/ml and treated at 350, 400, 450 MPa for 20 min at ...

Detection of viable but non-culturable Escherichia coli O157:H7 by PCR in combination with propidium monoazide.

Science.gov (United States)

Zhong, Junliang; Zhao, Xihong

2018-01-01

The aim of this study was to evaluate the applicability of the conventional PCR detection method combined with propidium monoazide (PMA) treatment for the detection of viable but non-culturable (VBNC) state Escherichia coli O157:H7 in ground beef meatballs. Under low temperature, E. coli O157:H7 cells were induced into the VBNC state in ground beef meatballs at - 20 °C after 152 days. The optimal PMA concentration of 5 µg/mL was obtained in beef meatball samples, which could completely inhibit the DNA amplification on dead cells (10 6  cells/mL) but with no inhibition on viable cells. The established PMA-PCR assay revealed that the VBNC counts exceeded 10 7  CFU/mL in artificial contamination beef samples, which could be used for semi-quantitative detection of VBNC cells in beef meatball samples. This study indicated that the PMA-PCR assay might be a potential method for detection of VBNC state E . coli O157:H7 cells in food products.

Prevalence and relatedness of Escherichia coli O157:H7 strains in the feces and on the hides and carcasses of U.S. meat goats at slaughter.

Science.gov (United States)

Jacob, M E; Foster, D M; Rogers, A T; Balcomb, C C; Sanderson, M W

2013-07-01

We determined the prevalences of Escherichia coli O157:H7 in feces, hide, and carcasses of meat goats at a U.S. processing plant. Prevalences were 11.1%, 2.7%, and 2.7%, respectively. Sixteen pulsed-field gel electrophoresis (PFGE) subtypes were identified among 49 E. coli O157:H7 isolates, some of which were present on multiple sample types or collection days.

IS3 profiling identifies the enterohaemorrhagic Escherichia coli O-island 62 in a distinct enteroaggregative E. coli lineage

Directory of Open Access Journals (Sweden)

Okeke Iruka N

2011-03-01

Full Text Available Abstract Background Enteroaggregative Escherichia coli (EAEC are important diarrhoeal pathogens that are defined by a HEp-2 adherence assay performed in specialist laboratories. Multilocus sequence typing (MLST has revealed that aggregative adherence is convergent, providing an explanation for why not all EAEC hybridize with the plasmid-derived probe for this category, designated CVD432. Some EAEC lineages are globally disseminated or more closely associated with disease. Results To identify genetic loci conserved within significant EAEC lineages, but absent from non-EAEC, IS3-based PCR profiles were generated for 22 well-characterised EAEC strains. Six bands that were conserved among, or missing from, specific EAEC lineages were cloned and sequenced. One band corresponded to the aggR gene, a plasmid-encoded regulator that has been used as a diagnostic target but predominantly detects EAEC bearing the plasmid already marked by CVD432. The sequence from a second band was homologous to an open-reading frame within the cryptic enterohaemorrhagic E. coli (EHEC O157 genomic island, designated O-island 62. Screening of an additional 46 EAEC strains revealed that the EHEC O-island 62 was only present in those EAEC strains belonging to the ECOR phylogenetic group D, largely comprised of sequence type (ST complexes 31, 38 and 394. Conclusions The EAEC 042 gene orf1600, which lies within the EAEC equivalent of O-island 62 island, can be used as a marker for EAEC strains belonging to the ECOR phylogenetic group D. The discovery of EHEC O-island 62 in EAEC validates the genetic profiling approach for identifying conserved loci among phylogenetically related strains.

Escherichia coli O157:H7 bacteriophage 241 isolated from an industrial cucumber fermentation at high acidity and salinity

Directory of Open Access Journals (Sweden)

Zhongjing eLu

2015-02-01

Full Text Available A novel phage, 241, specific for Escherichia coli O157:H7 was isolated from an industrial cucumber fermentation where both acidity (pH  3.7 and salinity ( 5% NaCl were high. The phage belongs to the Myoviridae family. Its latent period was 15 min and average burst size was 53 phage particles per infected cell. The phage was able to lyse 48 E. coli O157:H7 strains, but none of the 18 non-O157 strains (including E. coli O104:H7 or the 2 O antigen-negative mutants of O157:H7 strain, 43895per (also lacking H7 antigen and F12 (still expressing H7 antigen. However, the phage was able to lyse a per-complemented strain (43895perComp which expresses O157 antigen. These results indicated that phage 241 is specific for O157 antigen, and E. coli strains lacking O157 antigen were resistant to the phage infection, regardless of the presence or absence of H7 antigen. SDS-PAGE profile revealed at least 13 structural proteins of the phage. The phage DNA was resistant to many commonly used restriction endonucleases, suggesting the presence of modified nucleotides in the phage genome. At the multiplicity of infection of 10, 3 or 0.3, the phage caused a rapid cell lysis within 1 or 2 h, resulting in 3.5- or 4.5-log-unit reduction in cell concentration. The high lytic activity, specificity and tolerance to low pH and high salinity make phage 241 a potentially ideal biocontrol agent of E. coli O157:H7 in various foods. To our knowledge, this is the first report on E. coli O157:H7 phage isolated from high acidity and salinity environment.

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.

Sensitive detection of viable Escherichia coli O157:H7 from foods using a luciferase-reporter phage phiV10lux.

Science.gov (United States)

Kim, Jinwoo; Kim, Minsik; Kim, Seongmi; Ryu, Sangryeol

2017-08-02

Escherichia coli O157:H7, a major foodborne pathogen, is a major public health concern associated with life-threatening diseases such as hemolytic uremic syndrome. To alleviate this burden, a sensitive and rapid system is required to detect this pathogen in various kinds of foods. Herein, we propose a phage-based pathogen detection method to replace laborious and time-consuming conventional methods. We engineered an E. coli O157:H7-specific phage phiV10 to rapidly and sensitively detect this notorious pathogen. The luxCDABE operon was introduced into the phiV10 genome and allowed the engineered phage phiV10lux to generate bioluminescence proportional to the number of viable E. coli O157:H7 cells without any substrate addition. The phage phiV10lux was able to detect at least 1CFU/ml of E. coli O157:H7 in a pure culture within 40min after 5h of pre-incubation. In artificially contaminated romaine lettuce, apple juice (pH3.51), and ground beef, the reporter phage could detect approximately 10CFU/cm 2 , 13CFU/ml, and 17CFU/g of E. coli O157:H7, respectively. Taken together, the constructed reporter phage phiV10lux could be applied as a powerful tool for rapid and sensitive detection of live E. coli O157:H7 in foods. Copyright © 2017 Elsevier B.V. All rights reserved.

Antimicrobial activities of red wine-based formulations containing plant extracts against Escherichia coli O157:H7 and Salmonella enterica serovar Hadar

Science.gov (United States)

We evaluated the bactericidal activities of red wine and red wine solutions containing a commercial olive extract called Hydrox-12, oregano oil, or a mixture of both in red wine against the following foodborne pathogens: Escherichia coli O157:H7, Salmonella enterica, Listeria monocytogenes, and Stap...

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.

Caracemide, a site-specific irreversible inhibitor of protein R1 of Escherichia coli ribonucleotide reductase

DEFF Research Database (Denmark)

Larsen, I. K.; Cornett, Claus; Karlsson, M.

1992-01-01

The anticancer drug caracemide, N-acetyl-N,O-di(methylcarbamoyl)hydroxylamine, and one of its degradation products, N-acetyl-O-methylcarbamoyl-hydroxylamine, were found to inhibit the enzyme ribonucleotide reductase of Escherichia coli by specific interaction with its larger component protein R1....

Effectiveness of different antimicrobial washes combined with freezing against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes inoculated on blueberries

Science.gov (United States)

To ensure the microbial safety of produce including blueberries, sanitization is a critical step. This study evaluated the efficacy of sanitizers when coupled with frozen storage, in inactivating Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes inoculated on wild blueberri...

A rapid and highly sensitive protocol for the detection of Escherichia coli O157:H7 based on immunochromatography assay combined with the enrichment technique of immunomagnetic nanoparticles

Directory of Open Access Journals (Sweden)

Qi H

2011-11-01

Full Text Available Hui Qi1, Zhen Zhong1, Han-Xin Zhou1, Chun-Yan Deng1, Hai Zhu2, Jin-Feng Li2, Xi-Li Wang2, Fu-Rong Li1,31Clinical Medical Research Center, The Second Clinical Medical College (Shenzhen People's Hospital, Jinan University, 2Shenzhen Bioeasy Biotechnologies Co, Ltd, 3Shenzhen Institute of Gerontology, Shenzhen, People's Republic of ChinaBackground: Escherichia coli O157:H7 (E. coli O157:H7 is an important pathogenic bacterium that threatens human health. A rapid, simple, highly sensitive, and specific method for the detection of E. coli O157:H7 is necessary.Methods: In the present study, immunomagnetic nanoparticles (IMPs were prepared with nanopure iron as the core, coated with E. coli O157:H7 polyclonal antibodies. These IMPs were used in combination with immunochromatographic assay (ICA and used to establish highly sensitive and rapid kits (IMPs+ICA to detect E. coli O157:H7. The kits were then used to detect E. coli O157:H7 in 150 food samples and were compared with conventional ICA to evaluate their efficacy.Results: The average diameter of IMPs was 56 nm and the amount of adsorbed antibodies was 106.0 µg/mg. The sensitivity of ICA and IMPs+ICA was 105 colony-forming units/mL and 103 CFUs/mL, respectively, for purified E. coli O157:H7 solution. The sensitivity of IMPs+ICA was increased by two orders, and its specificity was similar to ICA.Conclusion: The kits have the potential to offer important social and economic benefits in the screening, monitoring, and control of food safety.Keywords: colloidal gold, immunomagnetic nanoparticles, Escherichia coli O157:H7, immunochromatographic assay

ANALISIS MIKROBIOLOGI ESCHERICHIA COLI O157:H7 PADA HASIL OLAHAN HEWAN SAPI DALAM PROSES PRODUKSINYA

Directory of Open Access Journals (Sweden)

Trini Sudiarti

2005-06-01

Full Text Available Microbiological analysis of Escherichia coli O157:H7 on Cow’s Products during the Production Process. The problem on food health is the high amount of bacterial contamination of food served by several kinds of food sellers, e.g. vendors, restaurants, caterers and food industries. Meat and milk products are kinds of food prone to contamination. To secure food against contamination by bacteria such as E. coli O157:H7, especially related to raw food, should beginwith the securing of products through the whole production process till it reaches the consumers. Although these pathogenic bacteria are part of the normal flora in the intestines of cattle, however we should be aware of the possibility of an outbreak in the community due to E. coli O157:H7 contamination of beef products. To anticipate the danger of an outbreak a study should be conducted to know about this microorganism from the beginning i.e. the production phaseuntil the seller phase. The aim of this research is to know the existence of E. coli O157:H7 on beef and milk products obtained from abattoirs, cow ranches, traditional markets and other sellers in addition with knowing the influencing factors on the spreading of the microorganism. The survey design used for this research is the cross sectional design. The material used for the tests are 250 ml water/milk and 250 gram beef/carcass. The bacterial tests included qualitative tests as follows: presumptive test, confirmed test, completed test, whereas quantitatively tests as follows: Total PlateCound (TPC, Most Probable Number (MPN, which is a near amount prediction of bacteria per 100 ml of water. Results showed that all meat (100% coming from abattoirs and traditional markets were contaminated with E. coli O157:H7, in addition with most of the fresh and pasteurized milk samples (73.3% coming from cattle ranches and home industries. Contamination was also found in most of the water samples (60% and in food handlers (41.7%.

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

African Journals Online (AJOL)

Erah

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

Antimicrobial resistance among commensal Escherichia coli from ...

African Journals Online (AJOL)

Commensal bacteria contribute to the distribution and persistence of antimicrobial resistance in the environment. This study monitored antimicrobial resistance in commensal Escherichia coli from the faeces of on-farm and slaughter cattle and beef. A total of 342 (89.5%) E. coli isolates were obtained from 382 samples.

Antimicrobial resistance among commensal Escherichia coli from ...

African Journals Online (AJOL)

user1

2012-07-19

Jul 19, 2012 ... Commensal bacteria contribute to the distribution and persistence of antimicrobial resistance in the environment. This study monitored antimicrobial resistance in commensal Escherichia coli from the faeces of on-farm and slaughter cattle and beef. A total of 342 (89.5%) E. coli isolates were obtained.

Variation in Resistance of Natural Isolates of Escherichia coli O157 to High Hydrostatic Pressure, Mild Heat, and Other Stresses

OpenAIRE

Benito, Amparo; Ventoura, Georgia; Casadei, Maria; Robinson, Tobin; Mackey, Bernard

1999-01-01

Strains of Escherichia coli O157 isolated from patients with clinical cases of food-borne illness and other sources exhibited wide differences in resistance to high hydrostatic pressure. The most pressure-resistant strains were also more resistant to mild heat than other strains. Strain C9490, a representative pressure-resistant strain, was also more resistant to acid, oxidative, and osmotic stresses than the pressure-sensitive strain NCTC 12079. Most of these differences in resistance were o...

Effectiveness of Active Packaging on Control of Escherichia Coli O157:H7 and Total Aerobic Bacteria on Iceberg Lettuce.

Science.gov (United States)

Lu, Haixia; Zhu, Junli; Li, Jianrong; Chen, Jinru

2015-06-01

Contaminated leafy green vegetables have been linked to several outbreaks of human gastrointestinal infections. Antimicrobial interventions that are adoptable by the fresh produce industry for control of pathogen contamination are in great demand. This study was undertaken to evaluate the efficacy of sustained active packaging on control of Escherichia coli O157:H7 and total aerobic bacteria on lettuce. Commercial Iceberg lettuce was inoculated with a 3-strain mixture of E. coli O157:H7 at 10(2) or 10(4) CFU/g. The contaminated lettuce and un-inoculated controls were placed respectively in 5 different active packaging structures. Traditional, nonactive packaging structure was included as controls. Packaged lettuce was stored at 4, 10, or 22 °C for 3 wk and sampled weekly for the population of E. coli O157:H7 and total aerobic bacteria. Results showed that packaging structures with ClO2 generator, CO2 generator, or one of the O2 scavengers effectively controlled the growth of E. coli O157:H7 and total aerobic bacteria under all storage conditions. Packaging structure with the ClO2 generator was most effective and no E. coli O157:H7 was detected in samples packaged in this structure except for those that were inoculated with 4 log CFU/g of E. coli O157:H7 and stored at 22 °C. Packaging structures with an oxygen scavenger and the allyl isothiocyanate generator were mostly ineffective in control of the growth of the bacteria on Iceberg lettuce. The research suggests that some of the packaging structures evaluated in the study can be used to control the presence of foodborne pathogens on leafy green vegetables. © 2015 Institute of Food Technologists®

Rapid and Accurate Detection of Bacteriophage Activity against Escherichia coli O157:H7 by Propidium Monoazide Real-Time PCR

Directory of Open Access Journals (Sweden)

Hui Liu

2014-01-01

Full Text Available Conventional methods to determine the efficacy of bacteriophage (phage for biocontrol of E. coli require several days, due to the need to culture bacteria. Furthermore, cell surface-attached phage particles may lyse bacterial cells during experiments, leading to an overestimation of phage activity. DNA-based real-time quantitative polymerase chain reaction (qPCR is a fast, sensitive, and highly specific means of enumerating pathogens. However, qPCR may underestimate phage activity due to its inability to distinguish viable from nonviable cells. In this study, we evaluated the suitability of propidium monoazide (PMA, a microbial membrane-impermeable dye that inhibits amplification of extracellular DNA and DNA within dead or membrane-compromised cells as a means of using qPCR to identify only intact E. coli cells that survive phage exposure. Escherichia coli O157:H7 strain R508N and 4 phages (T5-like, T1-like, T4-like, and O1-like were studied. Results compared PMA-qPCR and direct plating and confirmed that PMA could successfully inhibit amplification of DNA from compromised/damaged cells E. coli O157:H7. Compared to PMA-qPCR, direct plating overestimated (P < 0.01 phage efficacy as cell surface-attached phage particles lysed E. coli O157:H7 during the plating process. Treatment of samples with PMA in combination with qPCR can therefore be considered beneficial when assessing the efficacy of bacteriophage for biocontrol of E. coli O157:H7.

Association between the porcine Escherichia coli F18 receptor genotype and phenotype and susceptibility to colonisation and postweaning diarrhoea caused by E-coli O138 : F18

DEFF Research Database (Denmark)

Frydendahl, K.; Jensen, Tim Kåre; Andersen, Jens Strodl

2003-01-01

Porcine postweaning Escherichia coli enteritis is a cause of significant morbidity and mortality in pigs worldwide, and effective prevention remains an unsolved problem. This study examined the correlation between susceptibility of pigs to experimental infection with an E. coli F18 strain...... and the porcine intestinal F18 receptor genotypes. Thirty-one pigs classified as either belonging to the susceptible or the resistant genotype were inoculated with cultures of an E. coli 0138:F18 isolated from a pig with postweaning diarrhoea. Susceptibility to colonisation and diarrhoea was assessed by clinical...... and heterozygotic susceptible pigs. Faecal shedding of the challenge strain correlated with the genetic receptor profile. Twenty pigs examined immunohistochemically revealed focal to extensive small intestinal mucosal colonisation by E. coli O138:F18 in nine of 10 susceptible and three of 10 resistant pigs. Results...

[Changes in the redox potential and pO2 in heat shock to Escherichia coli].

Science.gov (United States)

Oktiabr'skiĭ, O N; Pshenichnov, R A

1982-01-01

When the growing culture of Escherichia coli was subjected to a temperature above 37 degrees C, the pO2 fell abruptly at 42 degrees C; a reversible decrease in the redox potential (ROP) down to the range of negative values was detected if the growth ceased at 46 degrees C. The drop in the ROP took from 6 to 10 min, with the maximal deviation of 42.5 mV. Such changes in the pO2 and ROP were not caused by a heat shock in the stationary cultures. The change in the ROP was not due to a change in the pH and pO2 of the medium. The authors believe that the effect should be attributed to an elimination of the ionic gradients and the electrochemical gradient delta muH+.

Strategies for Protein Overproduction in Escherichia coli.

Science.gov (United States)

Mott, John E.

1984-01-01

Examines heterologous expression in Escherichia coli and the role of regulatory sequences which control gene expression at transcription resulting in abundant production of messenger RNA and regulatory sequences in mRNA which promote efficient translation. Also examines the role of E. coli cells in stabilizing mRNA and protein that is…

Growth and survival of Escherichia coli O157:H7 and Listeria monocytogenes in egg products held at different temperatures.

Science.gov (United States)

Yang, S E; Chou, C C

2000-07-01

Growth and survival of Escherichia coli O157:H7 and Listeria monocytogenes in steamed eggs and scrambled eggs held at different temperatures (5, 18, 22, 37, 55, and 60 degrees C) were investigated in the present study. Among the holding temperatures tested, both pathogens multiplied best at 37 degrees C followed by 22, 18, and 5 degrees C. In general, E. coli O157:H7 grew better in the egg products than L. monocytogenes did at all the storage temperatures tested except at 5 degrees C. E. coli O157:H7 did not grow in steamed eggs and scrambled eggs held at 5 degrees C. L. monocytogenes showed a slight population increase of approximately 0.6 to 0.9 log CFU/g in these egg products at the end of the 36-h storage period at 5 degrees C. The population of both pathogens detected in the egg products was affected by the initial population, holding temperature, and length of the holding period. It was also noted that L. monocytogenes was more susceptible than E. coli O157:H7 in steamed eggs held at 60 degrees C. After holding at 60 degrees C for 1 h, no detectable viable cells of L. monocytogenes with a population reduction of 5.4 log CFU/g was observed in steamed eggs, whereas a lower population reduction of only approximately 0.5 log CFU/ml was noted for E. coli O157:H7.

Escherichia coli enterohemorrágica y síndrome urémico hemolítico en Argentina Enterohemorrhagic Escherichia coli and hemolytic-uremic syndrome in Argentina

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Mariana A. Rivero

2004-08-01

Full Text Available El síndrome urémico hemolítico (SUH.es un desorden multisistémico caracterizado por presentar insuficiencia renal aguda, anemia hemolítica microangiopática y trombocitopenia. Constituye la principal causa de insuficiencia renal aguda y la segunda causa de insuficiencia renal crónica y de transplante renal en niños en la Argentina. Actualmente, nuestro país presenta el registro más alto de SUH en todo el mundo, con aproximadamente 420 casos nuevos declarados anualmente y una incidencia de 12.2/100 000 niños menores de 5 años de edad. Se reconocen múltiples agentes etiológicos, aunque se considera a la infección por Escherichia coli enterohemorrágica (EHEC como la principal etiología de SUH. La gran mayoría de brotes epidémicos y casos esporádicos en humanos se han asociado con el serotipo O157:H7, aunque otros serotipos han sido también aislados, y éstos son un subgrupo de E. coli verocitotoxigénico (VTEC..El bovino es considerado el principal reservorio de VTEC. El contagio al hombre frecuentemente se debe al consumo de alimentos cárneos y lácteos contaminados, deficientemente cocidos o sin pasteurizar, o al contacto directo con los animales o con sus heces, consumo de agua, frutas o verduras contaminadas. También puede producirse contagio mediante el contacto interhumano.The hemolytic-uremic syndrome (HUS is a multisystemic disorder that is characterized by the onset of acute renal failure, microangiopathic hemolytic anemia and thrombocytopenia. It is the most common cause of acute renal failure and the second cause of chronic renal failure and renal transplantation in children in Argentina. Our country has the highest incidence of HUS in the world, with approximately 420 new cases observed each year with an incidence of 12.2 cases per 100 000 children in the age group 0-5 years. Numerous etiologic factors have been associated with HUS but the infection with enterohemorrhagic Escherichia coli (EHEC is considered the

Influence of Detection Methods in Characterizing Escherichia coli O157:H7 in Raw Goat Meat Using Conventional and Molecular Methods.

Science.gov (United States)

Tabashsum, Zajeba; Nazneen, Mafruha; Ahsan, C R; Bari, M L; Yasmin, M

2016-01-01

　Presence of Escherichia coli O157:H7 on fresh goat meat samples (n= 40) of Dhaka city was analyzed using conventional and molecular methods. A total of 86 presumptive E. coli O157:H7 colonies were isolated from 60% of the samples using selective agar plating method. After conventional biochemical assay followed by API 20E assay, only 11 isolates were found to be E. coli O157:H7. Further serological test identified only four isolates that has strong agglutination reaction against anti-H7 sensitized latex. The biochemically and serologically confirmed isolates were then screened for major virulence factors include eaeA, rfbE, fliC, stx1 and stx2 genes by PCR. PCR analysis of positive isolates showed, 10 isolates were eaeA and rfbE genes positive but fliC gene was only in six, indicating that these isolates were H7 positive with flagellum antigens which might not expressed or detected in serotyping tests. Multiplex PCR against eaeA, stx1 and stx2 genes of the isolates showed similar results as when done individually. These results revealed that only 7% of the primary presumptive E. coli O157:H7 was found to be stx producing E. coli O157:H7 and thus greatly influenced the detection of the pathogen in meat samples.

Cancerous patients and outbreak of Escherichia coli: an important issue in oncology

OpenAIRE

Joob, Beuy; Wiwanitkit, Viroj

2014-01-01

The widespread of the Escherichia coli outbreak in Europe becomes an important public concern at global level. The infection can be serious and might result in death. The retrospective literature review on this specific topic is performed. In this specific brief article, the author presented and discussed on the problem of Escherichia coli infection in the cancerous patients. This is an actual important issue in medical oncology for the scenario of Escherichia coli epidemic.

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...

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

[Construction and characterization of enterohemorrhagic Escherichia coli O157:H7 ppk- deleted strain].

Science.gov (United States)

Han, Peng; Sun, Qi; Zhao, Suhui; Zhang, Qiwei; Wan, Chengsong

2014-06-01

To construct enterohemorrhagic Escherichia coli (EHEC) O157: H7 ppk gene deletion strains and study its biological characteristics. The gene fragment of kanamycin resistance was amplified using a pair of homologous arm primers whose 5' and 3' ends were homologous with ppk gene and kanamycin resistance gene, respectively. EHEC O157: H7 EDL933w competent strains were prepared and transformed via electroporation with the amplification products. The ppk gene was replaced by kanamycin resistance gene using pKD46-mediated Red recombination system. The recombinant strain was confirmed by PCR and sequencing, and its morphology, growth ability and adhesion were assessed using Gram staining, OD600 value and Giemsa staining. We established a ppk-deleted EHEC O157:H7 EDL933w strain with kanamycin resistance and compared the biological characteristics of the wild-type and mutant strains, which may facilitate further study of the regulatory mechanism of ppk gene.

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

African Journals Online (AJOL)

E. coli O157 is an important serotype that caused many food borne outbreaks worldwide in the past decades. This study was carried out to estimate the prevalence and determine the antimicrobial susceptibility of E. coli O157 isolated from bovine carcasses and cecal contents at one abattoir in Jimma. A total of 300 samples ...

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

OpenAIRE

Zaghloul, T I; Doi, R H

1986-01-01

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

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

The Escherichia coli transcriptome linked to growth fitness

Directory of Open Access Journals (Sweden)

Bei-Wen Ying

2016-03-01

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

Occurrence and characterization of Shiga toxin-producing Escherichia coli O157:H7 and other non-sorbitol-fermenting E. coli in cattle and humans in urban areas of Morogoro, Tanzania.

Science.gov (United States)

Lupindu, Athumani M; Olsen, John E; Ngowi, Helena A; Msoffe, Peter L M; Mtambo, Madundo M; Scheutz, Flemming; Dalsgaard, Anders

2014-07-01

Escherichia coli strains such as Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli, enterotoxigenic, attaching, and effacing E. coli, and enteroinvasive E. coli cause diarrhea in humans. Although other serotypes exist, the most commonly reported STEC in outbreaks is O157:H7. A cross-sectional study was conducted to isolate and characterize non-sorbitol-fermenting (NSF) E. coli O157:H7 from urban and periurban livestock settings of Morogoro, Tanzania. Human stool, cattle feces, and soil and water samples were collected. Observations and questionnaire interview studies were used to gather information about cattle and manure management practices in the study area. E. coli were isolated on sorbitol MacConkey agar and characterized by conventional biochemical tests. Out of 1049 samples, 143 (13.7%) yielded NSF E. coli. Serological and antimicrobial tests and molecular typing were performed to NSF E. coli isolates. These procedures detected 10 (7%) pathogenic E. coli including STEC (n=7), enteropathogenic E. coli (EPEC) (n=2), and attaching and effacing E. coli (A/EEC) (n=1) strains. The STEC strains had the ability to produce VT1 and different VT2 toxin subtypes that caused cytopathic effects on Vero cells. The prevalence of STEC in cattle was 1.6%, out of which 0.9% was serotype O157:H7 and the overall prevalence of diarrheagenic E. coli in cattle was 2.2%. The serotypes O157:H7, O142:H34, O113:H21, O+:H-, O+:H16, and O25:H4 were identified. One ESBL-producing isolate showed the MLST type ST131. To our knowledge, this is the first finding in Tanzania of this recently emerged worldwide pandemic clonal group, causing widespread antimicrobial-resistant infections, and adds knowledge of the geographical distribution of ST131. Cattle manure was indiscriminately deposited within residential areas, and there was direct contact between humans and cattle feces during manure handling. Cattle and manure management practices expose humans, animals, and the environment

Principales características y diagnóstico de los grupos patógenos de Escherichia coli Diagnosis and main characteristics of Escherichia coli pathogenic groups

Directory of Open Access Journals (Sweden)

Guadalupe Rodríguez-Angeles

2002-09-01

Full Text Available Escherichia coli coloniza el intestino del hombre pocas horas después del nacimiento y se considera de flora normal, pero hay descritos seis grupos de E. coli productora de diarrea: enterotoxigénica (ETEC, enterohemorrágica (EHEC, enteroinvasiva (EIEC, enteropatógena (EPEC, enteroagregativa (EAEC y de adherencia difusa (DAEC. La bacteria se puede aislar e identificar tradicionalmente con base en sus características bioquímicas o serológicas, pero también se pueden estudiar sus mecanismos de patogenicidad mediante ensayos en cultivos celulares o modelos animales y, más recientemente, empleando técnicas de biología molecular que evidencian la presencia de genes involucrados en dichos mecanismos. La intención del presente trabajo es resaltar la importancia del estudio y diagnóstico de E. coli como patógeno capaz de causar casos aislados o brotes de diarrea, síndrome urémico hemolítico, colitis hemorrágica y cuadros de disentería, principalmente en niños; por esto es necesario conocer mejor a la bacteria y mantener la vigilancia epidemiológica.Escherichia coli colonizes the human intestinal tract within hours of birth and is considered a non-pathogenic member of the normal intestinal flora. However, there are six pathogenic groups that may produce diarrhea: enterotoxigenic (ETEC, enterohemorrhagic (EHEC, enteroinvasive (EIEC, enteropathogenic (EPEC, enteroaggregative (EAEC and diffusely adherent (DAEC groups. E. coli can be isolated and classified using traditional methods, by identifying its biochemical or serum characteristics. The pathogenic mechanisms may be studied in cell cultures and animal model assays, as well as more up to date molecular biology methods for study and diagnosis. The latter have proven that genes are involved in pathogenesis. The objective of the present work is to draw attention to the importance of E. coli as a pathogenic organism. This microorganism is an etiologic agent of sporadic cases of diarrhea

Risk factors associated with faecal shedding of verocytotoxin-producing Escherichia coli O157 in eight known-infected Danish dairy herds

DEFF Research Database (Denmark)

Rugbjerg, Helene; Nielsen, Eva Møller; Andersen, Jens Strodl

2003-01-01

A risk-factor study was performed in eight dairy herds found to excrete verocytotoxin-producing Escherichia coli (VTEC) O157 in a former prevalence study. Associations between excretion of VTEC O157 and management factors such as housing and feeding were analysed in a generalised linear mixed mod...... days with the mother after calving. Calves aged 5-24 months that had been moved within the last 2 weeks had a higher risk, but risk was reduced if fed barley silage. Cows fed grain or molasses had a higher risk of excreting VTEC O157....

The propagation of Escherichia Coli and of conservative tracers. A comparison

International Nuclear Information System (INIS)

Alexander, I.; Seiler, K.P.

1982-01-01

The propagation of Escherichia Coli (ATCC 11229, Gelsenkirchen) is compared with that of conservative tracers in groundwater. The experiments were performed with injection quantities of 10 7 , 10 8 , 10 10 and 10 11 of Escherichia Coli. Both, bacteria and conservative tracers pass their maximum at the same instant in the observation gauges. With injection quantities of more than 10 8 , the propagation of the Escherichia Coli sets in at the same time as it begins with the dyes. When the quantities range below 10 8 , the propagation begins after that of conservative tracers, because Coli bacteria were measured with a lower degree of detecting sensitivity than the tracers. With Coli injection quantities ranging above 10 10 , an increased filtering of these bacteria can be observed. Coli bacteria propagate more laterally than conservative tracers, however it could not be proved that this lateral propagation depends on the bacteria concentration. (orig.) [de

Frequency and risk-factors analysis of Escherichia coli O157:H7 in Bali-cattle.

Science.gov (United States)

Suardana, I Wayan; Widiasih, Dyah Ayu; Nugroho, Widagdo Sri; Wibowo, Michael Haryadi; Suyasa, I Nyoman

2017-08-01

Cattle are known as the main reservoir of zoonotic agents verocytotoxin-producing Escherichia coli. These bacteria are usually isolated from calves with diarrhea and/or mucus and blood. Tolerance of these agents to the environmental conditions will strengthen of their transmission among livestock. A total of 238 cattle fecal samples from four sub-districts in Badung, Bali were used in this study. Epidemiological data observed include cattle age, sex, cattle rearing system, the source of drinking water, weather, altitude, and type of cage floor, the cleanliness of cage floor, the slope of cage floor, and the level of cattle cleanliness. The study was initiated by culturing of samples onto eosin methylene blue agar, then Gram stained, and tested for indole, methyl-red, voges proskauer, and citrate, Potential E.coli isolates were then cultured onto sorbitol MacConkey agar, and further tested using O157 latex agglutination test and H7 antisera. Molecular identification was performed by analysis of the 16S rRNA gene, and epidemiological data was analyzed using STATA 12.0 software. The results showed, the prevalence of E. coli O157:H7 in cattle at Badung regency was 6.30% (15/238) covering four sub districts i.e. Petang, Abiansemal, Mengwi, and Kuta which their prevalence was 8.62%(5/58), 10%(6/60), 3.33%(2/60), and 3.33(2/60)%, respectively. The analysis of 16S rRNA gene confirmed of isolates as an E. coli O157:H7 strain with 99% similarities. Furthermore, the risk factors analysis showed that the slope of the cage floor has a highly significant effect (P<0.05) to the distribution of infection. Consequently, implementing this factor must be concerned in order to decrease of infection. Copyright © 2017 Elsevier B.V. All rights reserved.

The prevalence of Escherichia coli O157 and O157:H7 in ground beef and raw meatball by immunomagnetic separation and the detection of virulence genes using multiplex PCR.

Science.gov (United States)

Cadirci, Ozgür; Siriken, Belgin; Inat, Gökhan; Kevenk, Tahsin Onur

2010-03-01

The present study was conducted to investigate the presence of Escherichia coli O157 and O157:H7 strains and to detect the presence of the stx1, stx2, and eaeA genes in isolates derived from 200 samples (100 samples from fresh ground beef and 100 samples from raw meatball). The samples were purchased from the Samsun Province in Turkey, over a period of 1 year. Enrichment-based immunomagnetic separation and multiplex polymerase chain reaction were applied for these analyses. E. coli O157 was detected in five of the 200 (2.5%) samples tested (one isolated from ground beef and four from meatball samples), whereas E. coli O157: H7 was not detected in any sample. During the analysis, eight strains of E. coli O157 were obtained. The genes stx1, stx2, and eaeA were detected in two E. coli O157 isolates obtained from two meatball samples, whereas only the eaeA and the stx2 genes were detected in four E. coli O157 strains that were isolated from one meatball sample. None of the stx1, stx2, and eaeA was detected in the E. coli O157 isolates obtained from the ground beef and the one meatball samples. Copyright 2009 Elsevier Ltd. All rights reserved.

76 FR 20542 - Escherichia coli

Science.gov (United States)

2011-04-13

... beef, Escherichia coli and coliphages were found in chicken, fresh pork, fresh oyster, fresh mushrooms, lettuce, chicken pot pie, biscuit dough, deli loaf, deli roasted turkey, and package roasted chicken... surfaces, and in foods such as ground beef, pork sausage, chicken, oysters, cheese, fresh mushrooms, and...

Survival of genetically marked .i.Escherichia coli./i. O157:H7 in soil as affected by soil microbial community shifts

Czech Academy of Sciences Publication Activity Database

van Elsas, J.D.; Hill, P.; Chroňáková, Alica; Grekova, M.; Topalova, Y.; Elhottová, Dana; Krištůfek, Václav

-, č. 1 (2007), s. 204-214 ISSN 1751-7362 R&D Projects: GA MŠk LC06066 Grant - others:NATO(NL) ESP.EAP.CLG 981785 Institutional research plan: CEZ:AV0Z60660521 Source of funding: V - iné verejné zdroje Keywords : soil * fumigation * Escherichia coli O157:H7 Subject RIV: EH - Ecology, Behaviour

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

Science.gov (United States)

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

2017-09-01

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

Roles of individual radicals generated by a submerged dielectric barrier discharge plasma reactor during Escherichia coli O157:H7 inactivation

Energy Technology Data Exchange (ETDEWEB)

Khan, Muhammad Saiful Islam [Department of Food Biotechnology, University of Science and Technology, Daejeon, 305-350 (Korea, Republic of); Lee, Eun-Jung [Food Safety Research Group, Korea Food Research Institute, Seongnam-si, Gyeonggi-Do (Korea, Republic of); Kim, Yun-Ji, E-mail: yunji@kfri.re.kr [Department of Food Biotechnology, University of Science and Technology, Daejeon, 305-350 (Korea, Republic of); Food Safety Research Group, Korea Food Research Institute, Seongnam-si, Gyeonggi-Do (Korea, Republic of)

2015-10-15

A submerged dielectric barrier discharge plasma reactor (underwater DBD) has been used on Escherichia coli O157:H7 (ATCC 35150). Plasma treatment was carried out using clean dry air gas to investigate the individual effects of the radicals produced by underwater DBD on an E. coli O157:H7 suspension (8.0 log CFU/ml). E. coli O157:H7 was reduced by 6.0 log CFU/ml for 2 min of underwater DBD plasma treatment. Optical Emission Spectra (OES) shows that OH and NO (α, β) radicals, generated by underwater DBD along with ozone gas. E. coli O157:H7 were reduced by 2.3 log CFU/ml for 10 min of underwater DBD plasma treatment with the terephthalic acid (TA) OH radical scavenger solution, which is significantly lower (3.7 log CFU/ml) than the result obtained without using the OH radical scavenger. A maximum of 1.5 ppm of ozone gas was produced during the discharge of underwater DBD, and the obtained reduction difference in E.coli O157:H7 in presence and in absence of ozone gas was 1.68 log CFU/ml. The remainder of the 0.62 log CFU/ml reduction might be due to the effect of the NO (α, β) radicals or due to the combined effect of all the radicals produced by underwater DBD. A small amount of hydrogen peroxide was also generated but does not play any role in E. coli O157:H7 inactivation.

Quantitative Microbial Risk Assessment for Escherichia coli O157:H7 in Fresh-Cut Lettuce.

Science.gov (United States)

Pang, Hao; Lambertini, Elisabetta; Buchanan, Robert L; Schaffner, Donald W; Pradhan, Abani K

2017-02-01

Leafy green vegetables, including lettuce, are recognized as potential vehicles for foodborne pathogens such as Escherichia coli O157:H7. Fresh-cut lettuce is potentially at high risk of causing foodborne illnesses, as it is generally consumed without cooking. Quantitative microbial risk assessments (QMRAs) are gaining more attention as an effective tool to assess and control potential risks associated with foodborne pathogens. This study developed a QMRA model for E. coli O157:H7 in fresh-cut lettuce and evaluated the effects of different potential intervention strategies on the reduction of public health risks. The fresh-cut lettuce production and supply chain was modeled from field production, with both irrigation water and soil as initial contamination sources, to consumption at home. The baseline model (with no interventions) predicted a mean probability of 1 illness per 10 million servings and a mean of 2,160 illness cases per year in the United States. All intervention strategies evaluated (chlorine, ultrasound and organic acid, irradiation, bacteriophage, and consumer washing) significantly reduced the estimated mean number of illness cases when compared with the baseline model prediction (from 11.4- to 17.9-fold reduction). Sensitivity analyses indicated that retail and home storage temperature were the most important factors affecting the predicted number of illness cases. The developed QMRA model provided a framework for estimating risk associated with consumption of E. coli O157:H7-contaminated fresh-cut lettuce and can guide the evaluation and development of intervention strategies aimed at reducing such risk.

Epidemiology and clinical manifestations of enteroaggregative Escherichia coli

DEFF Research Database (Denmark)

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

2014-01-01

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

Quantitative Microbial Risk Assessment for Escherichia coli O157 : H7, Salmonella, and Listeria monocytogenes in Leafy Green Vegetables Consumed at Salad Bars

NARCIS (Netherlands)

Franz, E.; Tromp, S.O.; Rijgersberg, H.; Fels-Klerx, van der H.J.

2010-01-01

Fresh vegetables are increasingly recognized as a source of foodborne outbreaks in many parts of the world. The purpose of this study was to conduct a quantitative microbial risk assessment for Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes infection from consumption of leafy green

Effect of volumetric water content and clover (Trifolium incarnatum) on the survival of Escherichia coli O157:H7 in a soil matrix

Science.gov (United States)

Due to the inevitable introduction of zoonotic manure-born human pathogens, such as Escherichia coli O157:H7, into minimally processed, ready-to-eat and organic vegetable production systems via animal manure-based organic fertilizer, studies aimed at understanding the survival dynamics of these path...

DETECCIÓN DE Escherichia coli O157: H7 y Salmonella spp., EN CERDOS DEL DEPARTAMENTO DE CORDOBA

Directory of Open Access Journals (Sweden)

Jaime Vargas

2004-07-01

Full Text Available E. coli O157:H7 y Salmonella spp., son bacterias de distribución mundial causantes de enfermedades intestinales queafectan tanto al hombre como a LOS animales. ESTE estudio tuvo como objetivo determinar la presencia y frecuenciade aparición de E. coli O157:H7 y Salmonella spp., en los diferentes sistemas de producción porcina que se empleanen el departamento de Córdoba. Se realizó un estudio de corte descriptivo prospectivo, con un muestreo al azar enlos sistemas de explotación porcina intensiva y extensiva. Se procesaron 500 muestras de materia fecal de porcinos,250 provenientes del sistema extensivo y 250 del sistema intensivo. Para la detección E. coli y Salmonella spp., sellevaron a cabo procedimientos estándares microbiológicos. Los resultados mostraron una frecuencia de aparición deSalmonella spp., del 1%, el 0.2% en el sistema intensivo y el 0.8% en el sistema extensivo; no se aisló Escherichia coliO157:H7. Los resultados de resistencia y sensibilidad a los antibióticos en las cepas aisladas de Salmonella spp.,mostraron una sensibilidad del 100% al trimetoprim sulfametozasol, a la amikacina, al ceftriaxona, a la ciprofloxacina,a la gentamicina y al aztreonam y un 20% a la ampicilina y al sulbactam. Se concluye que la frecuencia de apariciónde Salmonella spp., en muestras coprológicas porcinas es baja, y nula para E. coli O157:H7, sin embargo, se debemantener la vigilancia sobre estos patógenos, por lo que se recomienda continuar los estudios epidemiológicos.

Growth and Extended Survival of Escherichia coli O157:H7 in Soil Organic Matter

Directory of Open Access Journals (Sweden)

Gitanjali NandaKafle

2018-04-01

Full Text Available Enterohaemorrhagic Escherichia coli, such as serotype O157:H7, are a leading cause of food-associated outbreaks. While the primary reservoir is associated with cattle, plant foods have been associated as sources of human infection. E. coli is able to grow in the tissue of food plants such as spinach. While fecal contamination is the primary suspect, soil has been underestimated as a potential reservoir. Persistence of bacterial populations in open systems is the product of growth, death, predation, and competition. Here we report that E. coli O157:H7 can grow using the soluble compounds in soil, and characterize the effect of soil growth on the stationary phase proteome. E. coli 933D (stxII− was cultured in Soil Extracted Soluble Organic Matter (SESOM and the culturable count determined for 24d. The proteomes of exponential and stationary phase populations were characterized by 2D gel electrophoresis and protein spots were identified by MALDI-TOF mass spectrometry. While LB controls displayed a death phase, SESOM grown population remained culturable for 24d, indicating an altered physiological state with superior longevity. This was not due to decreased cell density on entry to stationary phase as 24 h SESOM populations concentrated 10-fold retained their longevity. Principal component analysis showed that stationary phase proteomes from SESOM and LB were different. Differences included proteins involved in stress response, motility, membrane and wall composition, nutrient uptake, translation and protein turnover, and anabolic and catabolic pathways, indicating an altered physiological state of soil-grown cells entering stationary phase. The results suggest that E. coli may be a soil commensal that, in absence of predation and competition, maintains stable populations in soil.