A rapid, sensitive method for testing the activity of Escherichia coli 0157:H7 secreted cytotoxins against epithelial cells from the jejunum and descending colon of cattle

2008 ◽  
Vol 88 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Danica Baines ◽  
Luke Masson ◽  
Tim McAllister

Current methods for assessing Escherichia coli O157:H7 secreted cytotoxin activity are based on exposing human cell lines for 12 to 72 h and monitoring changes in cell morphology, adherence or enzyme release. These methods, although sensitive, use non-ruminant cell lines that may not represent cattle responses to E. coli O157:H7 secreted cytotoxins. The modified lawn assay used in this study was found to be a simple, fast and sensitive method for assessing cattle epithelial cell susceptibility to E. coli O157:H 7 secreted cytotoxins within 4 to 6 h. Key words: Escherichia coli O157:H7, cattle, intestine, cytotoxins, cytotoxicity


2000 ◽  
Vol 80 (4) ◽  
pp. 741-744 ◽  
Author(s):  
S. J. Buchko ◽  
R. A. Holley ◽  
W. O. Olson ◽  
V. P. J. Gannon ◽  
D. M. Veira

Cattle naturally infected with Escherichia coli O157:H7 were used to assess the effects of diet and feed withdrawal on the fecal shedding of E. coli O157:H7. Animals were fed an 80% concentrate diet (80% barley and 20% alfalfa silage), fasted for 48 h, fed a 100% forage diet (alfalfa silage), fasted for 48 h, and subsequently re-fed 100% forage (alfalfa silage). There were no differences in the numbers of animals positive for the shedding of E. coli O157:H7 when fed an 80% barley diet or an all-forage diet (P > 0.05) or during the fasting periods following each diet (P > 0.05). Upon re-feeding an all-forage diet following a 48-h fast, animals positive for E. coli O157:H7 shedding increased (P < 0.05), with 42.5% of the animals shedding the pathogen after 5 d. Re-feeding 100% forage following fasting appeared to have increased the number of animals shedding E. coli O157:H7 in their feces, which may have been influenced by diet in addition to fasting. Key words: Escherichia coli O157:H7, fasting, diet, cattle, fecal shedding



2003 ◽  
Vol 71 (3) ◽  
pp. 1470-1480 ◽  
Author(s):  
Joel D. Schilling ◽  
Steven M. Martin ◽  
David A. Hunstad ◽  
Kunal P. Patel ◽  
Matthew A. Mulvey ◽  
...  

ABSTRACT The gram-negative bacterium Escherichia coli is the leading cause of urinary tract infection. The interaction between type 1 piliated E. coli and bladder epithelial cells leads to the rapid production of inflammatory mediators, such as interleukin-6 (IL-6) and IL-8. Conflicting reports have been published in the literature regarding the mechanism by which uroepithelial cells are activated by type 1 piliated E. coli. In particular, the role of lipopolysaccharide (LPS) in these responses has been an area of significant debate. Much of the data arguing against LPS-mediated activation of bladder epithelial cells have come from studies using a renal epithelial cell line as an in vitro model of the urinary epithelium. In this report, we analyzed three bladder epithelial cell lines and demonstrated that they all respond to LPS. Furthermore, the LPS responsivity of the cell lines directly correlated with their ability to generate IL-6 after E. coli stimulation. The LPS receptor complex utilized by the bladder epithelial cell lines included CD14 and Toll-like receptors, and signaling involved the activation of NF-κB and p38 mitogen-activated protein kinase. Also, reverse transcription-PCR analysis demonstrated that bladder epithelial cells express CD14 mRNA. Thus, the molecular machinery utilized by bladder epithelial cells for the recognition of E. coli is very similar to that described for traditional innate immune cells, such as macrophages. In contrast, the A498 renal epithelial cell line did not express CD14, was hyporesponsive to LPS stimulation, and demonstrated poor IL-6 responses to E. coli.



2018 ◽  
Vol 5 (4) ◽  
pp. 88
Author(s):  
Elizabeth Antaki-Zukoski ◽  
Xunde Li ◽  
Patricia Pesavento ◽  
Tran Nguyen ◽  
Bruce Hoar ◽  
...  

Shiga toxin-producing Escherichia coli, like E. coli O157:H7, are important human and animal pathogens. Naturally-acquired E. coli O157:H7 infections occur in numerous species but, particularly, cattle have been identified as a significant reservoir for human cases. E. coli O157:H7 are isolated from a number of domestic and wild animals, including rodents that share a living space with cattle. These Shiga toxin-producing E. coli O157:H7 strains can be highly virulent in humans, but little is known about the sequelae of interspecies transfer. In a group of neonatal calves, we determined the differences in colonization patterns and lesions associated with infection using either a wildlife or bovine E. coli O157:H7 strain. In calves challenged with the wildlife E. coli O157:H7 strain, the large (descending) colon was solely colonized, which differed substantially from the calves inoculated with the bovine E. coli O157:H7 strain, where the spiral colon was the principal target of infection. This study also demonstrated that while both interspecies- and intraspecies-derived E. coli O157:H7 can infect young calves, the distribution and severity differs.



2020 ◽  
Vol 86 (20) ◽  
Author(s):  
Aamir Ali ◽  
Rafał Kolenda ◽  
Muhammad Moman Khan ◽  
Jörg Weinreich ◽  
Ganwu Li ◽  
...  

ABSTRACT Avian pathogenic Escherichia coli (APEC) is a major bacterial pathogen of commercial poultry contributing to extensive economic losses and contamination of the food chain. One of the initial steps in bacterial infection and successful colonization of the host is adhesion to the host cells. A random transposon mutant library (n = 1,300) of APEC IMT 5155 was screened phenotypically for adhesion to chicken (CHIC-8E11) and human (LoVo) intestinal epithelial cell lines. The detection and quantification of adherent bacteria were performed by a modified APEC-specific antibody staining assay using fluorescence microscopy coupled to automated VideoScan technology. Eleven mutants were found to have significantly altered adhesion to the cell lines examined. Mutated genes in these 11 “adhesion-altered mutants” were identified by arbitrary PCR and DNA sequencing. The genes were amplified from wild-type APEC IMT 5155, cloned, and transformed into the respective adhesion-altered mutants, and complementation was determined in adhesion assays. Here, we report contributions of the fdtA, rluD, yjhB, ecpR, and fdeC genes of APEC in adhesion to chicken and human intestinal cell lines. Identification of the roles of these genes in APEC pathogenesis will contribute to prevention and control of APEC infections. IMPORTANCE Avian pathogenic E. coli is not only pathogenic for commercial poultry but can also cause foodborne infections in humans utilizing the same attachment and virulence mechanisms. Our aim was to identify genes of avian pathogenic E. coli involved in adhesion to chicken and human cells in order to understand the colonization and pathogenesis of these bacteria. In contrast to the recent studies based on genotypic and bioinformatics data, we have used a combination of phenotypic and genotypic approaches for identification of novel genes contributing to adhesion in chicken and human cell lines. Identification of adhesion factors remains important, as antibodies elicited against such factors have shown potential to block colonization and ultimately prevent disease as prophylactic vaccines. Therefore, the data will augment the understanding of disease pathogenesis and ultimately in designing strategies against the infections.



2021 ◽  
Vol 15 ◽  
pp. 117822342110101
Author(s):  
Komang Januartha Putra Pinatih ◽  
I Wayan Suardana ◽  
Dyah Ayu Widiasih ◽  
Hamong Suharsono

Purpose: It has been suggested that Shiga-like toxins produced by Escherichia coli O157:H7 could be used as novel therapeutic agents against malignant tumors. In addition, the antitumor potency of local isolates from Indonesia, which are known to be less toxic than the control isolate ATCC 43894, has not yet been tested. The study aimed to analyze local strains of E. coli O157:H7 as a proapoptosis agent on the T47 breast cancer cell line. Methods: As many as 30 culture cells of T47D breast cancer cell line were subjected to purified extracts of Shiga-like toxin originating from 5 local isolates of E. coli O157:H7: KL-48(2), SM-25(1), SM-7(1), DS-21(4), and 1 isolate ATCC 43894 which was used as a control. Toxin production of each isolate was detected using a sandwich enzyme-linked immunosorbent assay, and the treatment of cell lines was observed for 24 hours, with 2 replications; 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide tests and acridine orange/ethidium bromide double staining assays were used for detection and analyses of apoptosis. Results: The study showed 2 local strains of E. coli O157:H7 (codes KL-48(2) and SM-25(1)) had toxins positive at titer 5 and 10 μg/100 μL. These titers were lower than the control isolate ATCC 43894, but they had a necrosis effect higher ( P < .05), ie, 80.3%, than control isolate, ie, 63.3%. Other local strain SM-25(1) also had a good necrosis effect. It has a nondifferent necrosis effect ( P > .05) with the control isolate ATCC 43894, ie, 13.0% from 13.3%. Conclusion: This study concludes that the Shiga toxin produced by E. coli O157:H7 local isolate (Indonesia) has potential as a proapoptotic and/or necrotic agent for treating T47 breast cancer cell lines, as effectively as ATCC 43894 control isolates.



2008 ◽  
Vol 88 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Danica Baines ◽  
Luke Masson ◽  
Tim McAllister

Enterohemorrhagic Escherichia coli (EHEC) O157:H7-secreted cytotoxins are toxic to target cells and enhance colonization of intestinal tissues in disease-susceptible animals. It is unclear what role, if any, EHEC O157:H7-secreted cytotoxins play in the colonization of intestinal tissues of healthy reservoir animals. We previously reported that EHEC O157:H7 colonization sites were associated with focal hemorrhages in the jejunum and descending colon of persistent shedding cattle, suggesting a potential role for cytotoxins in EHEC O157:H7 colonization. We have used a traditional EHEC O157:H7 IVOC adherence assay and a novel lawn assay to examine the role of EHEC O157:H7-secreted cytotoxins in EHEC O157:H7 strain colonization of the jejunum and descending colon of non-persistent and persistent shedding cattle. Four EHEC O157:H7 strains that were previously reported to differentially colonize cattle produced cytotoxins that were differentially active against epithelial cells from the jejunum and descending colon. There was a relationship between EHEC O157:H7-secreted cytotoxin activity and strain adherence for epithelial cells from the jejunum and descending colon of cattle. There was also a greater susceptibility of epithelial cells from the jejunum and descending colon to EHEC O157:H7-secreted cytotoxins of persistent shedding cattle compared with non-persistent shedding cattle. Addition of the most active secreted cytotoxins from EHEC O157:H7 R318N to the IVOC adherence assays significantly increased the adhere nce of the most (R318N) and least (H4420N) virulent EHEC O157:H7 strain to intestinal tissues. The current study supports a role for EHEC O157:H7-secreted cytotoxins in enhancing EHEC O157:H7 colonization of intestinal tissues of cattle. Key words: Escherichia coli O157:H7, cattle, intestine, cytotoxins, colonization



2020 ◽  
Vol 16 (3) ◽  
pp. 373-380
Author(s):  
Mohammad B. Zendeh ◽  
Vadood Razavilar ◽  
Hamid Mirzaei ◽  
Khosrow Mohammadi

Background: Escherichia coli O157:H7 is one of the most common causes of contamination in Lighvan cheese processing. Using from natural antimicrobial essential oils is applied method to decrease the rate of microbial contamination of dairy products. The present investigation was done to study the antimicrobial effects of Z. multiflora and O. basilicum essential oils on survival of E. coli O157:H7 during ripening of traditional Lighvan cheese. Methods: Leaves of the Z. multiflora and O. basilicum plants were subjected to the Clevenger apparatus. Concentrations of 0, 100 and 200 ppm of the Z. multiflora and 0, 50 and 100 ppm of O. basilicum essential oils and also 103 and 105 cfu/ml numbers of E. coli O157:H7 were used. The numbers of the E. coli O157:H7 bacteria were analyzed during the days 0, 30, 60 and 90 of the ripening period. Results: Z. multiflora and O. basilicum essential oils had considerable antimicrobial effects against E. coli O157:H7. Using the essential oils caused decrease in the numbers of E. coli O157:H7 bacteria in 90th days of ripening (P <0.05). Using from Z. multiflora at concentration of 200 ppm can reduce the survival of E. coli O157:H7 in Lighvan cheese. Conclusion: Using Z. multiflora and O. basilicum essential oils as good antimicrobial agents can reduce the risk of foodborne bacteria and especially E. coli O157:H7 in food products.



Author(s):  
Cheng Liu ◽  
Shuiqin Fang ◽  
Yachen Tian ◽  
Youxue Wu ◽  
Meijiao Wu ◽  
...  

Escherichia coli O157:H7 ( E. coli O157:H7) is a dangerous foodborne pathogen, mainly found in beef, milk, fruits, and their products, causing harm to human health or even death. Therefore, the detection of E. coli O157:H7 in food is particularly important. In this paper, we report a lateral flow immunoassay strip (LFIS) based on aggregation-induced emission (AIE) material labeling antigen as a fluorescent probe for the rapid detection of E. coli O157:H7. The detection sensitivity of the strip is 105 CFU/mL, which is 10 times higher than that of the colloidal gold test strip. This method has good specificity and stability and can be used to detect about 250 CFU of E. coli O157:H7 successfully in 25 g or 25 mL of beef, jelly, and milk. AIE-LFIS might be valuable in monitoring food pathogens for rapid detection.



2009 ◽  
Vol 89 (2) ◽  
pp. 285-293 ◽  
Author(s):  
S J Bach ◽  
R P Johnson ◽  
K. Stanford ◽  
T A McAllister

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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