EnterohemorrhagicEscherichia coliO157: epidemiology and ecology in bovine production environments

2002 ◽  
Vol 3 (2) ◽  
pp. 83-94 ◽  
Author(s):  
David G. Renter ◽  
Jan M. Sargeant
Keyword(s):  
Health Concern ◽  
Level Control ◽  
Fecal Shedding ◽  
Farm Level ◽  
E Coli ◽  
Production Factors ◽  
Closed Systems ◽  
Human Infections ◽  
On Farm

AbstractEnterohemorrhagicEscherichia coli, particularly the O157(:H7) serogroup, has become a worldwide public health concern. Since cattle feces are often implicated as the source ofE. coliO157 in human infections, considerable resources have been devoted to defining the epidemiology and ecology ofE. coliO157 in cattle environments so that control might begin at the farm level. Diagnostic limitations and the complexity of often interrelated microbial, animal, herd, environmental and production factors have hindered the determination of the epidemiology, ecology and subsequent farm-level control ofE. coliO157. The widespread distribution ofE. coliO157, the transitory nature of fecal shedding, multiple potential environmental sources, lack of species specificity, and age-, feed- and time-related differences in cattle prevalence are documented. However, the significance and/or role of these factors in the epidemiology and ecology ofE. coliO157 is still unclear. Cattle are a major source ofE. coliO157, but it may be simplistic to believe that most herds are relatively closed systems with small percentages of cattle serving as true reservoirs. Practical on-farm control may require explicit definitions of the seemingly complex system(s) and the microbial, animal, herd, environmental and production factors involved in the multiplication, maintenance and transmission ofE. coliO157.

scholarly journals Prevalence and Virulence Gene Profiles of Escherichia coli O157 from Cattle Slaughtered in Buea, Cameroon

2020 ◽  
Author(s):  
Elvis Achondou Akomoneh ◽  
Seraphine Nkie Esemu ◽  
Achah Jerome Kfusi ◽  
Roland N. Ndip ◽  
Lucy M. Ndip
Keyword(s):  
Escherichia Coli ◽  
Virulence Genes ◽  
Foodborne Pathogen ◽  
Virulence Gene ◽  
Latex Agglutination ◽  
Health Concern ◽  
E Coli ◽  
Uremic Syndrome ◽  
Human Infections ◽  
Pcr Targeting

ABSTRACTBackgroundEscherichia coli O157 is an emerging foodborne pathogen of great public health concern. It has been associated with bloody diarrhoea, haemorrhagic colitis and haemolytic uremic syndrome in humans. Most human infections have been traced to cattle and the consumption of contaminated cattle products. In order to understand the risk associated with the consumption of cattle products, this study sought to investigate the prevalence and identify virulence genes in E. coli O157 from cattle in Cameroon.MethodA total of 512 rectal samples were obtained and analysed using conventional bacteriological methods (enrichment on modified Tryptone Soy Broth and selective plating on Cefixime-Tellurite Sorbitol Mac-Conkey Agar) for the isolation of E. coli O157. Presumptive E. coli O157 isolates were confirmed serologically using E. COLIPRO™ O157 latex agglutination test and molecularly using PCR targeting the rfb gene in the isolates. Characterisation of the confirmed E. coli O157 strains was done by amplification of stx1, stx2, eaeA and hlyA virulence genes using both singleplex and multiplex PCR.ResultsE. coli O157 was detected in 56 (10.9%) of the 512 samples examined. The presence of the virulence genes stx2, eaeA and hylA was demonstrated in 96.4% (54/56) of the isolates and stx1 in 40 (71.4%) of the 54. The isolates exhibited three genetic profiles (I-III) with I (stx1, stx2, eaeA and hlyA) being the most prevalent (40/56; 71.4%) while two isolates had none of the virulence genes tested.ConclusionA proportion of cattle slaughtered in abattoirs in Buea are infected with pathogenic E. coli O157 and could be a potential source of human infections. We recommend proper animal food processing measures and proper hygiene be prescribed and implemented to reduce the risk of beef contamination.

Escherichia coliO157:H7 in beef cattle: on farm contamination and pre-slaughter control methods

2011 ◽  
Vol 12 (2) ◽  
pp. 197-211 ◽  
Author(s):  
J. M. Soon ◽  
S. A. Chadd ◽  
R. N. Baines
Keyword(s):  
Beef Cattle ◽  
Pathogenic Bacteria ◽  
Control Measures ◽  
Product Recalls ◽  
Control Methods ◽  
Farm Level ◽  
E Coli ◽  
Beef Products ◽  
Handling Practices ◽  
On Farm

AbstractThis paper addresses food safety in beef cattle production, with particular emphasis on factors that affect the prevalence ofEscherichia coliO157:H7 in beef cattle and on control methods that have been investigated. Product recalls and foodborne diseases due to this organism continue to occur even though control measures have been under investigation for over 20 years. Most meatborne outbreaks are due to improper food handling practices and consumption of undercooked meat. However, the majority of pathogenic bacteria that can spread at slaughter by cross-contamination can be traced back to the farm rather than originating from the slaughter plant. This would ideally require the adoption of rigorous on-farm intervention strategies to mitigate risks at the farm level. On-farm strategies to control and reduceE. coliO157:H7 at the farm level will reduce the risk of carcass contamination at slaughter and processing facilities although they will not eliminateE. coliO157:H7. The most successful strategy for reducing the risk of contamination of beef and beef products will involve the implementation of both pre- and post-harvest measures.

scholarly journals Multidrug-Resistance and Virulence-Related Properties of Diarrheagenic Escherichia Coli in Urban River: A Possible Source and Dissemination of Human Infections

2021 ◽  
Author(s):  
Barbara Araújo Nogueira ◽  
Julianna Giordano Botelho Olivella ◽  
Bruna Ribeiro Sued-Karam ◽  
Paula Marcele Afonso Pereira Ribeiro ◽  
Valmir Oliveira ◽  
...  
Keyword(s):  
Rio De Janeiro ◽  
Microbiological Quality ◽  
Health Concern ◽  
Drug Resistant ◽  
Antimicrobial Susceptibility Test ◽  
E Coli ◽  
Virulence Potential ◽  
Bacterial Interaction ◽  
Human Infections

Abstract The presence of multi-drug resistant (MDR) E. coli harboring virulence pathotypes in aquatic systems is a public health concern due to an increase number of cases of infections and outbreaks in industrialized and developing countries. The aim of the present study was to evaluate the microbiological quality of Joana river, located at Rio de Janeiro, by analyzing E. coli bacteria contamination and to investigate virulence properties and MDR profiles by phenotypic and genotypic methods, including bacterial interaction with Caco-2 cells. A total of 34 E. coli were identified by MALDI-TOF and 20 E. coli were characterized as MDR when submitted to antimicrobial susceptibility test. Evaluation by multiplex-PCR of MDR E. coli demonstrated the presence of virulence pathotypes: EHEC (stx1, stx2, eae genes), STEC (stx2 gene) and EIEC/STEC (stx2, iaL genes). Virulence potential was demonstrated by the ability to adhere and survive within Caco-2 cells of MDR E. coli pathotypes (n = 4). In conclusion, this study demonstrates the presence of diarrheagenic MDR E. coli in river water at Rio de Janeiro. The possibility of aquatic environment dissemination of antimicrobial resistance and human contamination leading to community and nosocomial infections due to virulent MDR E. coli water-borne pathogens is a matter of concern.

Concentration determination of chromatin in unstained resin-embedded sections by means of Z-contrast in STEM

1990 ◽  
Vol 48 (2) ◽  
pp. 186-187
Author(s):  
M. Haider ◽  
B. Bohrmann
Keyword(s):  
Energy Loss ◽  
Freeze Substitution ◽  
Biological Macromolecules ◽  
Local Concentration ◽  
E Coli ◽  
Concentration Determination ◽  
Phosphorous Content ◽  
Z Contrast ◽  
Electron Energy Loss

The technique of Z-contrast in STEM offers the possibility to determine the local concentration of macromolecules like lipids, proteins or DNA. Contrast formation depends on the atomic composition of the particular structure. In the case of DNA, its phosphorous content discriminates it from other biological macromolecules. In our studies, sections of E. coli, the dinoflagellate Amphidinium carterae and Euglena spec. cells were used which were obtained by cryofixation followed by freeze-substitution into acetone with 3% glutaraldehyde. The samples were then embedded either in Lowicryl HM20 at low temperature or in Epon at high temperature. Sections were coated on both sides with 30Å carbon.The DF- and the inelastic image have been recorded simultaneously with a Cryo-STEM. This Cryo-STEM is equipped with a highly dispersive Electron Energy Loss Spectrometer. With this instrument pure Z-contrast can be achieved either with a Filtered DF-image divided by the inelastic image or, as is used in this paper, by dividing the conventional DF-image by an inelastic image which has been recorded with an inelastic detector whose response is dependent on the total energy loss of the inelastically scattered electrons.

Co-expression of recombinant single chain variable fragment recognizing blood antigen fused with sumo and chaperones in Escherichia coli

2018 ◽  
Vol 40 (4) ◽  
Author(s):  
Dang Thi Ngoc Ha ◽  
Le Thi Thu Hong ◽  
Truong Nam Hai
Keyword(s):  
Recombinant Antibody ◽  
Blood Type ◽  
Soluble Form ◽  
Supernatant Fraction ◽  
Blood Group Antigens ◽  
Single Chain ◽  
E Coli ◽  
Recombinant Scfv ◽  
Single Chain Variable Fragments

Single chain variable fragments (scFv) have widely been used in research, diagnosis and treatment, but the scFv is considered as difficult protein for expression in E. coli. In previous studies, we expressed a construction of recombinant single chain variable fragments again antigen specific for blood type A (antiA-scFv) individually or fused with Trx or SUMO. However, soluble fraction was low abandant and only approximately 40% when fused with Trx, the other cases were expressed in form of inclusion body. Therefore, it was difficult for purification, refolding and activity assesment. In thispaper, we demonstrated a suitable construction for soluble production of antiA-scFv fused with SUMO (SM/antiA-scFv) in presence of chaparones. Under fermentation with 0.1 mM IPTG at 20oC, the SM/antiA-scFv was entirely expressed in soluble form. Importantly, after cleavage from SUMO with SUMOprotease, antiA-scFv was still maintained in the supernatant fraction. Therefore, it can help ensure bioactivity and is useful for purification process. To the best of our knowledge, this is the first report showing soluble recombinant scFv fused with SUMO in presence of chaperone for determination of blood group antigens. Thus, this result facilitates the optimal study of soluble expression, purification and bioactivity determination of the antiA-scFv recombinant antibody. 

MAKSIMASI KEUNTUNGAN USAHA PUKAT CINCIN DI NEGERI LATUHALAT PADA MUSIM TIMUR

2018 ◽  
Vol 2 (1) ◽  
pp. 22-32
Author(s):  
Willem Talakua ◽  
Eygner Gerald Talakua
Keyword(s):  
Linear Programming ◽  
Production Factors ◽  
Maximum Profit ◽  
Analysis Methods ◽  
Profit Analysis ◽  
Business Profit ◽  
Programming Analysis

The purpose of this study is to study the maximization of business profits through the determination of the optimal use of production factors in the trawl ring business in Latuhalat. Observations and direct interviews based on questionnaires were carried out on 3 fishermen who owned trawl ring businesses in 3 hamlets in Latuhalat. Data were analyzed using business profit analysis methods and linear programming analysis. The results showed that: 1). The optimal use of production factors for trawling by the respondents in Latuhalat is 41 - 45 trips in June using 15.2 - 21.1 liters of gasoline, 280.9 - 304.4 liters of gasoline, 10.1 - 21 , 2 liters of oil, using labor as much as 15-17 people for 8 hours / day, and using transportation and FAD services as much as 351.3 - 360 HOK or 8 hours per day; and 2). The maximum profit that can be obtained from trawling rings by respondents in Latuhalat is Rp. 165,545,500 - up to Rp. 184,800,000, - in June. To achieve this maximum profit, respondents need to produce 25,270.3 kg of fish to 27,540.98 kg in June.

Identification of N-Substituted Triazolo-azetidines as Novel Antibacterials using pDualrep2 HTS Platform

2019 ◽  
Vol 22 (5) ◽  
pp. 346-354
Author(s):  
Yan A. Ivanenkov ◽  
Renat S. Yamidanov ◽  
Ilya A. Osterman ◽  
Petr V. Sergiev ◽  
Vladimir A. Aladinskiy ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Large Scale ◽  
Underlying Mechanism ◽  
Luciferase Assay ◽  
Reporter System ◽  
E Coli ◽  
Starting Point ◽  
High Concentrations ◽  
Mic Value

Aim and Objective: Antibiotic resistance is a serious constraint to the development of new effective antibacterials. Therefore, the discovery of the new antibacterials remains one of the main challenges in modern medicinal chemistry. This study was undertaken to identify novel molecules with antibacterial activity. Materials and Methods: Using our unique double-reporter system, in-house large-scale HTS campaign was conducted for the identification of antibacterial potency of small-molecule compounds. The construction allows us to visually assess the underlying mechanism of action. After the initial HTS and rescreen procedure, luciferase assay, C14-test, determination of MIC value and PrestoBlue test were carried out. Results: HTS rounds and rescreen campaign have revealed the antibacterial activity of a series of Nsubstituted triazolo-azetidines and their isosteric derivatives that has not been reported previously. Primary hit-molecule demonstrated a MIC value of 12.5 µg/mL against E. coli Δ tolC with signs of translation blockage and no SOS-response. Translation inhibition (26%, luciferase assay) was achieved at high concentrations up to 160 µg/mL, while no activity was found using C14-test. The compound did not demonstrate cytotoxicity in the PrestoBlue assay against a panel of eukaryotic cells. Within a series of direct structural analogues bearing the same or bioisosteric scaffold, compound 2 was found to have an improved antibacterial potency (MIC=6.25 µg/mL) close to Erythromycin (MIC=2.5-5 µg/mL) against the same strain. In contrast to the parent hit, this compound was more active and selective, and provided a robust IP position. Conclusion: N-substituted triazolo-azetidine scaffold may be used as a versatile starting point for the development of novel active and selective antibacterial compounds.

scholarly journals Antibiotic tolerance is associated with a broad and complex transcriptional response in E. coli

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Heather S. Deter ◽  
Tahmina Hossain ◽  
Nicholas C. Butzin
Keyword(s):  
Transcriptional Regulatory Network ◽  
Transcriptional Response ◽  
Regulatory Proteins ◽  
Health Concern ◽  
Transcriptional Networks ◽  
Antibiotic Tolerance ◽  
Multiple Gene ◽  
E Coli ◽  
Transcriptional Regulatory ◽  
Antibiotic Efficacy

AbstractAntibiotic treatment kills a large portion of a population, while a small, tolerant subpopulation survives. Tolerant bacteria disrupt antibiotic efficacy and increase the likelihood that a population gains antibiotic resistance, a growing health concern. We examined how E. coli transcriptional networks changed in response to lethal ampicillin concentrations. We are the first to apply transcriptional regulatory network (TRN) analysis to antibiotic tolerance by leveraging existing knowledge and our transcriptional data. TRN analysis shows that gene expression changes specific to ampicillin treatment are likely caused by specific sigma and transcription factors typically regulated by proteolysis. These results demonstrate that to survive lethal concentration of ampicillin specific regulatory proteins change activity and cause a coordinated transcriptional response that leverages multiple gene systems.

scholarly journals Using seed respiration as a tool for calculating optimal soaking times for ‘on-farm’ seed priming of barley (Hordeum vulgare)

2021 ◽  
pp. 1-9
Author(s):  
Javier Carrillo-Reche ◽  
Adrian C. Newton ◽  
Richard S. Quilliam
Keyword(s):  
Morphological Changes ◽  
Low Cost ◽  
Germination Rate ◽  
Seed Priming ◽  
Embryonic Axes ◽  
Seedling Vigour ◽  
Soaking Time ◽  
On Farm ◽  
Seed Respiration

Abstract A low-cost technique named ‘on-farm’ seed priming is increasingly being recognized as an effective approach to maximize crop establishment. It consists of anaerobically soaking seeds in water before sowing resulting in rapid and uniform germination, and enhanced seedling vigour. The extent of these benefits depends on the soaking time. The current determination of optimal soaking time by germination assays and mini-plot trials is resource-intensive, as it is species/genotype-specific. This study aimed to determine the potential of the seed respiration rate (an indicator of metabolic activity) and seed morphological changes during barley priming as predictors of the priming benefits and, thus, facilitate the determination of optimal soaking times. A series of germination tests revealed that the germination rate is mostly attributable to the rapid hydration of embryo tissues, as the highest gains in the germination rate occurred before the resumption of respiration. Germination uniformity, however, was not significantly improved until seeds were primed for at least 8 h, that is, after a first respiration burst was initiated. The maximum seedling vigour was attained when the priming was stopped just before the beginning of the differentiation of embryonic axes (20 h) after which vigour began to decrease (‘over-priming’). The onset of embryonic axis elongation was preceded by a second respiration burst, which can be used as a marker for priming optimization. Thus, monitoring of seed respiration provides a rapid and inexpensive alternative to the current practice. The method could be carried out by agricultural institutions to provide recommended optimal soaking times for the common barley varieties within a specific region.

Bacteriophages reduce Escherichia coli O157:H7 levels in experimentally inoculated sheep

2009 ◽  
Vol 89 (2) ◽  
pp. 285-293 ◽  
Author(s):  
S J Bach ◽  
R P Johnson ◽  
K. Stanford ◽  
T A McAllister
Keyword(s):  
Escherichia Coli ◽  
Oral Administration ◽  
Coliform Bacteria ◽  
Escherichia Coli O157 ◽  
Fecal Shedding ◽  
Total Coliforms ◽  
E Coli ◽  
Oral Inoculation ◽  
Experimental Treatments ◽  
And Control

Bacteriophage biocontrol has potential as a means of mitigating the prevalence of Escherichia coli O157:H7 in ruminants. The efficacy of oral administration of bacteriophages for reducing fecal shedding of E. coli O157:H7 by sheep was evaluated using 20 Canadian Arcott rams (50.0 ± 3.0) housed in four rooms (n = 5) in a contained facility. The rams had ad libitum access to drinking water and a pelleted barley-based total mixed ration, delivered once daily. Experimental treatments consisted of administration of E. coli O157:H7 (O157), E. coli O157:H7+bacteriophages (O157+phage), bacteriophages (phage), and control (CON). Oral inoculation of the rams with 109 CFU of a mixture of four nalidixic acid-resistant strains of E. coli O157:H7 was performed on day 0. A mixture of 1010 PFU of bacteriophages P5, P8 and P11 was administered on days -2, -1, 0, 6 and 7. Fecal samples collected on 14 occasions over 21 d were analyzed for E. coli O157:H7, total E. coli, total coliforms and bacteriophages. Sheep in treatment O157+phage shed fewer (P < 0.05) E. coli O157:H7 than did sheep in treatment O157. Populations of total coliforms and total E. coli were similar (P < 0.05) among treatments, implying that bacteriophage lysis of non-target E. coli and coliform bacteria in the gastrointestinal tract did not occur. Bacteriophage numbers declined rapidly over 21 d, which likely reduced the chance of collision between bacteria and bacteriophage. Oral administration of bacteriophages reduced shedding of E. coli O157:H7 by sheep, but a delivery system that would protect bacteriophages during passage through the intestine may increase the effectiveness of this strategy as well as allow phage to be administered in the feed.Key words: Escherichia coli O157:H7, bacteriophage, sheep, environment, coliforms

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