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1دورية أكاديمية
المؤلفون: Nagwa T. Elsharawy, Mariem A.A. Ramadan, Abeera M. Elsayed
المصدر: Journal of Advanced Veterinary Research, Vol 13, Iss 10 (2023)
مصطلحات موضوعية: Integrons, Shiga toxin-producing E. coli, Gentamycin, Heat-Labile Toxin, plasmids, Veterinary medicine, SF600-1100
الوصف: Escherichia coli gene mutations (plasmids, integrons, and transposons) have instigated multidrug resistance (MDR) against various antimicrobials. This study detected antibiotic-resistance genes (genotypic and phenotypic) in E. coli and performed Whole-genome sequencing to discover MDR-associated E. coli genes in mullet fish. E. coli isolates were serologically identified and their antimicrobial sensitivity was tested. E. coli presence was confirmed in 35% of the mullet fish samples. Cephalosporins, tetracyclines, and sulfonamides presented higher efficiency against E. coli. The serological investigation revealed the presence of STEC (O157:H7, 50%), ETEC (O142, 20%), EHEC (O26:H11,15%), and EPEC (15%) in mullet meat samples. A symmetrical band represented the Subunit B of the Shiga-like toxin (SLT) genewhereas the Heat-labile toxin (LT) gene was found in plasmid and genomic DNA-detected strains. The results revealed the hazardous nature of STEC for mullet meat consumers. The study recommends improving the hygienic conditions during the mullet handling and processing steps, which will minimize antibiotic usage and resistance.
وصف الملف: electronic resource
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2دورية أكاديمية
المؤلفون: Michelle Qiu Carter, Beatriz Quiñones, Nicole Laniohan, Diana Carychao, Antares Pham, Xiaohua He, Michael Cooley
المصدر: Frontiers in Microbiology, Vol 14 (2023)
مصطلحات موضوعية: comparative pathogenomics, Shiga toxins, heat-labile toxin, cytotoxicity, biofilms, virulence genes, Microbiology, QR1-502
الوصف: Shiga toxin-producing Escherichia coli (STEC) consists of diverse strains differing in genetic make-up and virulence potential. To better understand the pathogenicity potential of STEC carried by the wildlife, three STEC and one E. coli strains isolated from wild birds near a major agricultural region in California were selected for comparative pathogenomic analyses. Three American crow (Corvus brachyrhynchos) strains, RM9088, RM9513, and RM10410, belonging to phylogroup A with serotypes O109:H48, O9:H30, and O113:H4, respectively, and a red-winged blackbird (Agelaius phoeniceus) strain RM14516 in phylogroup D with serotype O17:H18, were examined. Shiga toxin genes were identified in RM9088 (stx1a), RM10410 (stx1a + stx2d), and RM14516 (stx2a). Unlike STEC O157:H7 strain EDL933, none of the avian STEC strains harbored the pathogenicity islands OI-122, OI-57, and the locus of enterocyte effacement, therefore the type III secretion system biogenesis genes and related effector genes were absent in the three avian STEC genomes. Interestingly, all avian STEC strains exhibited greater (RM9088 and RM14516) or comparable (RM10410) cytotoxicity levels compared with EDL933. Comparative pathogenomic analyses revealed that RM9088 harbored numerous genes encoding toxins, toxins delivery systems, and adherence factors, including heat-labile enterotoxin, serine protease autotransporter toxin Pic, type VI secretion systems, protein adhesin Paa, fimbrial adhesin K88, and colonization factor antigen I. RM9088 also harbored a 36-Kb high pathogenicity island, which is related to iron acquisition and pathogenicity in Yersinia spp. Strain RM14516 carried an acid fitness island like the one in EDL933, containing a nine gene cluster involved in iron acquisition. Genes encoding extracellular serine protease EspP, subtilase cytotoxin, F1C fimbriae, and inverse autotransporter adhesin IatC were only detected in RM14516, and genes encoding serine protease autotransporter EspI and P fimbriae were only identified in RM10410. Although all curli genes were present in avian STEC strains, production of curli fimbriae was only detected for RM9088 and RM14516. Consistently, strong, moderate, and little biofilms were observed for RM9088, RM14516, and RM10410, respectively. Our study revealed novel combinations of virulence factors in two avian strains, which exhibited high level of cytotoxicity and strong biofilm formation. Comparative pathogenomics is powerful in assessing pathogenicity and health risk of STEC strains.
وصف الملف: electronic resource
العلاقة: https://www.frontiersin.org/articles/10.3389/fmicb.2023.1214081/fullTest; https://doaj.org/toc/1664-302XTest
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3دورية أكاديمية
المؤلفون: Jun-Young Park, Seung-Hak Cho
المصدر: Frontiers in Immunology, Vol 14 (2023)
مصطلحات موضوعية: enterotoxigenic Escherichia coli (ETEC), heat-labile toxin (LT), epitope mapping, peptide, monoclonal antibody, Immunologic diseases. Allergy, RC581-607
الوصف: BackgroundEnterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea through two enterotoxins, a heat-labile toxin and a heat-stable toxin. These toxins alter the cellular signaling pathways, ultimately triggering an increase in chloride secretion and watery diarrhea.ObjectiveFor the development of an ETEC vaccine, we attempted to construct a peptide-specific monoclonal antibody library against heat-labile enterotoxin A subunit (LT-A) by epitope mapping using synthetic peptides.MethodsSera produced by five mice immunized with recombinant LT-A protein were examined for specific recognition with synthetic 15-mer and 34-mer peptides of LT-A proteins using enzyme-linked immunosorbent assay. The analysis revealed that the synthetic peptides number 8, 16, 24, 33, 36, 38, and 39 reacted with an anti-LT-A polyclonal antibody. For the possible prediction of LT-A epitopes, each full-length protein sequence was subjected to BCPreds analysis and three-dimensional protein structure analysis. The data showed that three peptides (synthetic peptide numbers: 33, 36, and 38–39) have identical antigenic specificities with LT-A protein, suggesting the usefulness of these linear peptide epitopes.ResultsBased on these peptides, we produced monoclonal antibodies to improve the specificity of LT-A detection. Monoclonal antibodies produced from two peptides (numbers 33 and 36) showed affinity for an LT-A recombinant antigen. Moreover, peptide epitope prediction analysis showed that the sites of the three peptides were identical to those exhibiting actual antigenicity. Also, it was confirmed that the amino acid sequence that actually showed antigenicity was included in the peptide predicted only by ETEC-LT-A-33. Also, the specificity of the antibody for ETEC-LT-A-33 was validated using bacterial cells, and the neutralizing effect of the antibody was determined by assessing cytokine release in infected HCT-8 cells.ConclusionThe monoclonal antibodies produced in this study are useful toolsfor vaccine production against ETEC and can be used to identify peptide antigencandidates.
وصف الملف: electronic resource
العلاقة: https://www.frontiersin.org/articles/10.3389/fimmu.2023.1152910/fullTest; https://doaj.org/toc/1664-3224Test
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4دورية أكاديمية
المؤلفون: El-Waseif, Amr A.1, 1, Awad, Gehad S.2, El Maaty, Sabah A. Abo2, Hassan, Mervat G.2
المصدر: Research Journal of Pharmacy and Technology 15(7):2957-2961. 2022
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5دورية أكاديمية
المؤلفون: Petra Girardi, Taufiqur Rahman Bhuiyan, Samuel B. Lundin, Shushan Harutyunyan, Irene Neuhauser, Farhana Khanam, Gábor Nagy, Valéria Szijártó, Tamás Henics, Eszter Nagy, Ali M. Harandi, Firdausi Qadri
المصدر: Microorganisms, Vol 11, Iss 10, p 2524 (2023)
مصطلحات موضوعية: ETEC, heat-labile toxin (LT), heat-stable toxin (ST), natural infection, endemic population, children, Biology (General), QH301-705.5
الوصف: A sero-epidemiology study was conducted in Dhaka, Bangladesh between January 2020 and February 2021 to assess the immune responses to ETEC infection in adults and children. (1) Background: Enterotoxigenic Escherichia coli infection is a main cause of diarrheal disease in endemic countries. The characterization of the immune responses evoked by natural infection can guide vaccine development efforts. (2) Methods: A total of 617 adult and 480 pediatric diarrheal patients were screened, and 43 adults and 46 children (below 5 years of age) with an acute ETEC infection completed the study. The plasma samples were analyzed for antibody responses against the ETEC toxins. (3) Results: Heat-stable toxin (ST)-positive ETEC is the main cause of ETEC infection in adults, unlike in children in an endemic setting. We detected very low levels of anti-ST antibodies, and no ST-neutralizing activity. However, infection with ETEC strains expressing the heat-labile toxin (LT) induced systemic antibody responses in less than 25% of subjects. The antibody levels against LTA and LTB, as well as cholera toxin (CT), correlated well. The anti-LT antibodies were shown to have LT- and CT- neutralizing activity. The antibody reactivity against linear LT epitopes did not correlate with toxin-neutralizing activity. (4) Conclusions: Unlike LT, ST is a poor antigen and even adults have low anti-ST antibody levels that do not allow for the detection of toxin-neutralizing activity.
وصف الملف: electronic resource
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6دورية أكاديمية
المؤلفون: Das, Soumita, Jayaratne, Rashini, Barrett, Kim E
المصدر: Cellular and molecular gastroenterology and hepatology. 6(1)
مصطلحات موضوعية: ATP, adenosine triphosphate, ATPase, adenosine triphosphatase, CDI, Clostridium difficile infection, CFTR, cystic fibrosis transmembrane conductance regulator, CLCA1, chloride channel accessory 1, CT, cholera toxin, CXCR2, C-X-C motif chemokine receptor 2, DRA, down-regulated in adenoma, Diarrhea, ENaC, epithelial sodium channel, EPEC, enteropathogenic Escherichia coli, ETEC, enterotoxigenic Escherichia coli, Enteric Pathogen, Epithelium, EspG, Escherichia coli secreted protein G, GPR39, G-protein coupled receptor 39, Ion Transport, KCC, potassium-chloride cotransporter, LPA, lysophosphatidic acid, LT, heat-labile toxin, NHE, sodium/hydrogen exchanger, NHERF2, sodium/hydrogen exchanger regulatory factor 2, NKCC, sodium-potassium-2 chloride cotransporter, ORT, oral rehydration therapy, PKC, protein kinase C, SGLT1, sodium-glucose cotransporter 1, SLC, solute carrier, ST, heat-stabile toxin, TNF, tumor necrosis factor, Tcd, Clostridium difficile toxin, ZnR, zinc sensing receptor, cAMP, adenosine 3′, 5′-cyclic monophosphate, ATP, adenosine triphosphate, ATPase, adenosine triphosphatase, CDI, Clostridium difficile infection, CFTR, cystic fibrosis transmembrane conductance regulator, CLCA1, chloride channel accessory 1, CT, cholera toxin, CXCR2, C-X-C motif chemokine receptor 2, DRA, down-regulated in adenoma, ENaC, epithelial sodium channel, EPEC, enteropathogenic Escherichia coli, ETEC, enterotoxigenic Escherichia coli, EspG, Escherichia coli secreted protein G, GPR39, G-protein coupled receptor 39, KCC, potassium-chloride cotransporter, LPA, lysophosphatidic acid, LT, heat-labile toxin, NHE, sodium/hydrogen exchanger, NHERF2, sodium/hydrogen exchanger regulatory factor 2, NKCC, sodium-potassium-2 chloride cotransporter, ORT, oral rehydration therapy, PKC, protein kinase C, SGLT1, sodium-glucose cotransporter 1, SLC, solute carrier, ST, heat-stabile toxin, TNF, tumor necrosis factor, Tcd, Clostridium difficile toxin, ZnR, zinc sensing receptor, cAMP, adenosine 3′, 5′-cyclic monophosphate
الوصف: Every year, enteric infections and associated diarrhea kill millions of people. The situation is compounded by increases in the number of enteric pathogens that are acquiring resistance to antibiotics, as well as (hitherto) a relative paucity of information on host molecular targets that may contribute to diarrhea. Many forms of diarrheal disease depend on the dysregulation of intestinal ion transporters, and an associated imbalance between secretory and absorptive functions of the intestinal epithelium. A number of major transporters have been implicated in the pathogenesis of diarrheal diseases and thus an understanding of their expression, localization, and regulation after infection with various bacteria, viruses, and protozoa likely will prove critical in designing new therapies. This article surveys our understanding of transporters that are modulated by specific pathogens and the mechanism(s) involved, thereby illuminating targets that might be exploited for new therapeutic approaches.
وصف الملف: application/pdf
الوصول الحر: https://escholarship.org/uc/item/1r43v5jtTest
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7دورية أكاديمية
المصدر: Journal of Advanced Veterinary Research; Vol. 13 No. 10 (2023): Special Issue: The Fifth Conference for the Faculty of Veterinary Medicine, Suez Canal University, Egypt (Food Safety and Animal Health); 2029-2033 ; 2090-6277 ; 2090-6269
مصطلحات موضوعية: Integrons, Shiga toxin-producing E. coli, Gentamycin, Heat-Labile Toxin, plasmids
الوصف: Escherichia coli gene mutations (plasmids, integrons, and transposons) have instigated multidrug resistance (MDR) against various antimicrobials. This study detected antibiotic-resistance genes (genotypic and phenotypic) in E. coli and performed Whole-genome sequencing to discover MDR-associated E. coli genes in mullet fish. E. coli isolates were serologically identified and their antimicrobial sensitivity was tested. E. coli presence was confirmed in 35% of the mullet fish samples. Cephalosporins, tetracyclines, and sulfonamides presented higher efficiency against E. coli. The serological investigation revealed the presence of STEC (O157:H7, 50%), ETEC (O142, 20%), EHEC (O26:H11,15%), and EPEC (15%) in mullet meat samples. A symmetrical band represented the Subunit B of the Shiga-like toxin (SLT) genewhereas the Heat-labile toxin (LT) gene was found in plasmid and genomic DNA-detected strains. The results revealed the hazardous nature of STEC for mullet meat consumers. The study recommends improving the hygienic conditions during the mullet handling and processing steps, which will minimize antibiotic usage and resistance.
وصف الملف: application/pdf
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8دورية أكاديمية
المصدر: Vaccines, Vol 10, Iss 12, p 2161 (2022)
مصطلحات موضوعية: live cholera vaccine, cold chain free, cholera toxin, heat-labile toxin, Vibrio cholerae O139, enterotoxigenic Escherichia coli (ETEC), Medicine
الوصف: In low- and middle-income countries, diarrhoeal diseases are the second most common cause of mortality in children, mainly caused by enterotoxin-producing bacteria, such as Shigella, Vibrio, Salmonella, and Escherichia coli. Cholera and traveller’s diarrhoea are caused by Vibrio cholerae (O1 and O139 serogroups) and enterotoxigenic Escherichia coli (ETEC), respectively. The cholera toxin (CT) produced by V. cholerae and the heat-labile enterotoxin (LT) of ETEC are closely related by structure, function, and the immunological response to them. There is no exclusive vaccine for ETEC; however, cholera vaccines based on the CT-B component elicit a short-term cross-protection against ETEC infection. In this context, the cross-protective efficacy of MyCholTM, a prototype cold-chain-free, live-attenuated, oral cholera vaccine against V. cholerae O139 was evaluated in BALB/c mice. The 100% lethal dose (LD100) of 109 CFU/mL of the ETEC H10407 strain was used for the challenge studies. The mice immunised with MyChol™ survived the challenge by producing anti-CT antibodies, which cross-neutralised the LT toxin with no body weight loss and no sign of diarrhoea. Compared to unimmunised mice, the immunised mice elicited the neutralising antitoxin that markedly decreased ETEC colonisation and fluid accumulation caused by ETEC H10407 in the intestines. The immunised mice recorded higher antibody titres, including anti-CT IgG, anti-LT IgG, anti-CT-B IgG, and anti-LTB IgG. Only a two-fold rise in anti-CT/CT-B/LT/LT-B IgA was recorded in serum samples from immunised mice. No bactericidal antibodies against ETEC H10407 were detected. This investigation demonstrates the safety, immunogenicity, and cross-protective efficacy of MyCholTM against the ETEC H10407 challenge in BALB/c mice.
وصف الملف: electronic resource
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9دورية أكاديمية
مصطلحات موضوعية: Microbiology, Molecular Biology, Biotechnology, Immunology, Cancer, Statistics, Infectious Diseases, Space Science, Biological Sciences not elsewhere classified, using established loop, resource poor settings, mediated isothermal amplification, lyophilized reaction strips, including analytical sensitivity, heat stable toxins, heat labile toxin, end user ’, div >< p, time sufficiently sensitive, 1 cfu respectively, 5 , 4 , shigella spp <, culture methods used, sensitive diagnostic assay, methods used, ipah <, e <, coli <, shigella strains
الوصف: (DOCX)
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10دورية أكاديمية
مصطلحات موضوعية: Microbiology, Molecular Biology, Biotechnology, Immunology, Cancer, Statistics, Infectious Diseases, Space Science, Biological Sciences not elsewhere classified, using established loop, resource poor settings, mediated isothermal amplification, lyophilized reaction strips, including analytical sensitivity, heat stable toxins, heat labile toxin, end user ’, div >< p, time sufficiently sensitive, 1 cfu respectively, 5 , 4 , shigella spp <, culture methods used, sensitive diagnostic assay, methods used, ipah <, e <, coli <, shigella strains
الوصف: (DOCX)
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