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Lee W, Ha J, Choi J, Jung Y, Kim E, An ES, Kim SH, Shin H, Ryu S, Kim SH, Kim HY. Genetic and virulence characteristics of hybrid Shiga toxin-producing and atypical enteropathogenic Escherichia coli strains isolated in South Korea. Front Microbiol 2024; 15:1398262. [PMID: 38812694 PMCID: PMC11133561 DOI: 10.3389/fmicb.2024.1398262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Accepted: 04/29/2024] [Indexed: 05/31/2024] Open
Abstract
Introduction The predominant hybrid pathogenic E. coli, enterohemorrhagic E. coli (EHEC), combines characteristics of Shiga toxin-producing E. coli (STEC) and enteropathogenic E. coli (EPEC), contributing to global outbreaks with severe symptoms including fatal consequences. Since EHEC infection was designated as a notifiable disease in 2000 in South Korea, around 2000 cases have been reported, averaging approximately 90 cases annually. Aim In this work, genome-based characteristic analysis and cell-based assay of hybrid STEC/aEPEC strains isolated from livestock feces, animal source foods, and water in South Korea was performed. Methods To identify the virulence and antimicrobial resistance genes, determining the phylogenetic position of hybrid STEC/aEPEC strains isolated in South Korea, a combination of real-time PCR and whole-genome sequencing (WGS) was used. Additionally, to assess the virulence of the hybrid strains and compare them with genomic characterization, we performed a cell cytotoxicity and invasion assays. Results The hybrid STEC/aEPEC strains harbored stx and eae genes, encoding Shiga toxins and E. coli attachment/effacement related protein of STEC and EPEC, respectively. Furthermore, all hybrid strains harbored plasmid-carried enterohemolysin(ehxCABD), a key virulence factor in prevalent pathogenic E. coli infections, such as diarrheal disease and hemolytic-uremic syndrome (HUS). Genome-wide phylogenetic analysis revealed a close association between all hybrid strains and specific EPEC strains, suggesting the potential acquisition of Stx phages during STEC/aEPEC hybrid formation. Some hybrid strains showed cytotoxic activity against HeLa cells and invasive properties against epithelial cells. Notably, all STEC/aEPEC hybrids with sequence type (ST) 1,034 (n = 11) exhibited higher invasiveness than those with E2348/69. This highlights the importance of investigating potential correlations between STs and virulence characteristics of E. coli hybrid strains. Conclusion Through genome-based characterization, we confirmed that the hybrid STEC/aEPEC strains are likely EPEC strains that have acquired STEC virulence genes via phage. Furthermore, our results emphasize the potential increased danger to humans posed by hybrid STEC/aEPEC strains isolated in South Korea, containing both stx and eaeA, compared to STEC or EPEC alone.
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Affiliation(s)
- Woojung Lee
- Division of Food Microbiology, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Republic of Korea
- Institute of Life Sciences & Resources and Department of Food Science and Biotechnology, Kyung Hee University, Yongin, Republic of Korea
| | - Jina Ha
- Division of Food Microbiology, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Republic of Korea
| | - Jaehyun Choi
- Division of Food Microbiology, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Republic of Korea
| | - Yewon Jung
- Department of Food and Animal Biotechnology, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Eiseul Kim
- Institute of Life Sciences & Resources and Department of Food Science and Biotechnology, Kyung Hee University, Yongin, Republic of Korea
| | - Eun Sook An
- Division of Food Microbiology, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Republic of Korea
| | - Seung Hwan Kim
- Division of Food Microbiology, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Republic of Korea
| | - Hakdong Shin
- Department of Biotechnology, and Carbohydrate Bioproduct Research Center, Sejong University, Seoul, Republic of Korea
| | - Sangryeol Ryu
- Department of Food and Animal Biotechnology, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
- Center for Food and Bioconvergence, Seoul National University, Seoul, Republic of Korea
| | - Soon Han Kim
- Division of Food Microbiology, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Republic of Korea
| | - Hae-Yeong Kim
- Institute of Life Sciences & Resources and Department of Food Science and Biotechnology, Kyung Hee University, Yongin, Republic of Korea
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Asmani F, Khavari-Nejad RA, Salmanian AH, Amani J. In Silico designing and immunogenic production of the multimeric CfaB*ST, CfaE, LTB antigen as a peptide vaccine against Enterotoxigenic Escherichia coli. Microb Pathog 2021; 158:105087. [PMID: 34256098 DOI: 10.1016/j.micpath.2021.105087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 07/06/2021] [Accepted: 07/06/2021] [Indexed: 11/28/2022]
Abstract
Enterotoxigenic Escherichia coli (ETEC) is the most frequent bacterial cause of diarrhea particularly reported in children of developing countries and also travelers. Enterotoxins and colonization factor antigens (CFAs) are two major virulence factors in ETEC pathogenesis. Colonization factor antigen I (CFA/I) includes major pilin subunit CfaB, and a minor adhesive subunit (CfaE), and enterotoxins consisting of heat-labile toxin subunit B (LTB) and heat-stable toxin (ST). Chimeric proteins (CCL) carrying epitopes and adjuvant sequences increase the possibility of eliciting a broad cellular or effective immune response. In the present study, a chimeric candidate vaccine containing CfaB*ST, CfaE, and LTB (CCL) was designed via in silico techniques. This chimeric gene was synthesized by using codon usage of E. coli for increasing the expression of the recombinant protein. After designing the chimeric construct, it showed a high antigenicity index estimated by the vaxiJen server. Linear and conformational B-cell epitopes were identified and indicated suitable immunogenicity of this multimeric recombinant protein. Thermodynamic analyses for mRNA structures revealed the appropriate folding of the RNA representative good stability of this molecule. In silico scanning was done to predict the 3D structure of the protein, and modeling was validated using the Ramachandran plot analysis. The chimeric protein (rCCL) was expressed in a prokaryotic expression system (E. coli), purified, and analyzed for their immunogenic properties. It was revealed that the production of a high titer of antibody produced in immunized mice could neutralize the ETEC using the rabbit ileal loop tests. The results indicated that the protein inferred from the recombinant protein (rCCL) construct could act as a proper vaccine candidate against three critical causative agents of diarrheal bacteria at the same time.
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Affiliation(s)
- Farzaneh Asmani
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | | | - Ali Hatef Salmanian
- Department of Agricultural Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Jafar Amani
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
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Kazemi R, Akhavian A, Amani J, Salimian J, Motamedi MJ, Mousavi A, Jafari M, Salmanian AH. Immunogenic properties of trivalent recombinant protein composed of B-subunits of LT, STX-2, and CT toxins. Microbes Infect 2016; 18:421-429. [DOI: 10.1016/j.micinf.2016.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 03/01/2016] [Accepted: 03/02/2016] [Indexed: 01/31/2023]
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Alerasol M, Mousavi Gargari SL, Nazarian S, Bagheri S. Immunogenicity of a fusion protein comprising coli surface antigen 3 and labile B subunit of enterotoxigenic Escherichia coli. IRANIAN BIOMEDICAL JOURNAL 2014; 18:212-218. [PMID: 25326019 PMCID: PMC4225060 DOI: 10.6091/ibj.1344.2014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Background: Enterotoxigenic Escherichia coli (ETEC) strains are the major causes of diarrheal disease in humans and animals. Colonization factors and enterotoxins are the major virulence factors in ETEC pathogenesis. For the broad-spectrum protection against ETEC, one could focus on colonization factors and non-toxic heat labile as a vaccine candidate. Methods: A fusion protein is composed of a major fimbrial subunit of coli surface antigen 3, and the heat-labile B subunit (LTB) was constructed as a chimeric immunogen. For optimum level expression of protein, the gene was synthesized with codon bias of E. coli. Also, recombinant protein was expressed in E. coli BL21DE3. ELISA and Western tests were carried out for determination of antigen and specificity of antibody raised against recombinant protein in animals. The anti-toxicity and anti-adherence properties of the immune sera against ETEC were also evaluated. Results: Immunological analyses showed the production of high titer of specific antibody in immunized mice. The built-in LTB retains native toxin properties which were approved by GM1 binding assay. Pre-treatment of the ETEC cells with anti-sera significantly decreased their adhesion to Caco-2 cells. Conclusion: The results indicated the efficacy of the recombinant chimeric protein as an effective immunogen inducing strong humoral response. The designated chimer would be an interesting prototype for a vaccine and worthy of further investigation.
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Moss J, Vaughan M. ADP-ribosylation of guanyl nucleotide-binding regulatory proteins by bacterial toxins. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 61:303-79. [PMID: 3128060 DOI: 10.1002/9780470123072.ch6] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- J Moss
- Laboratory of Cellular Metabolism, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892
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Rogerie F, Marecat A, Gambade S, Dupond F, Beaubois P, Lange M. Characterization of Shiga toxin producing E. coli and O157 serotype E. coli isolated in France from healthy domestic cattle. Int J Food Microbiol 2001; 63:217-23. [PMID: 11246905 DOI: 10.1016/s0168-1605(00)00422-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A study was carried out in France in collaboration with the meat industry to investigate the occurrence and characteristics of Shiga toxin-producing E. coli (STEC) and O157 E. coli in a population of healthy bovines representative of French livestock. A total of 851 animals belonging to three bovine classes (106 young bulls, 374 dairy cows and 371 meat cows) were included in the study. Samples of feces and of the corresponding carcasses were collected from March 97 to August 97 in seven abattoirs spread throughout the national territory. STEC cultures from the 1702 samples were screened using PCR for the presence of stx genes. Positive samples were further subjected to colony blot hybridization and to O157-specific immunomagnetic separation. Probe-positive colonies and O157 colonies were then analyzed for the presence of virulence genes and phenotypic characters (serotype, Stx production). In 154 (18.1%) feces and 91 (10.7%) carcass samples stx genes were detected. Two hundred and twenty-two STEC colonies were isolated from 67 (7.9%) feces and 16 (1.9%) carcass samples, with 183 STEC isolated from feces and 39 from carcasses. Only eight O157 isolates were collected from feces samples. None of these O157 E. coli isolates presented stx genes and thus could not be considered as pathogenic regarding hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). In 3.2% of STEC isolated from feces and in 10.2% of STEC from carcasses eae genes were detected. In 17% of STEC from feces and in 30.7% from carcasses ehx genes were detected. Using these data, the 222 STEC colonies could be classified in 11 different 'virulence patterns' (presence/absence of stx1, stx2, eae and ehx genes), showing that more than 77% of isolates presented only one virulence factor. Only three STEC on 222 colonies (1.3%) presented the three virulence factors stx, eae and ehx in association, none of them reacting with antisera specific for enterohemorrhagic E. coli. (EHEC). These data, together with the fact that only five isolates on the 222 (2.2%) reacted with such antisera (three O111 and two O26 isolates) demonstrated that the natural bacterial populations isolated during this study were clearly distinct from EHEC.
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Affiliation(s)
- F Rogerie
- Institut Pasteur de Lille, Département de Microbiologie des Ecosystèmes, France
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Koprowski H, Levine MM, Anderson RJ, Losonsky G, Pizza M, Barry EM. Attenuated Shigella flexneri 2a vaccine strain CVD 1204 expressing colonization factor antigen I and mutant heat-labile enterotoxin of enterotoxigenic Escherichia coli. Infect Immun 2000; 68:4884-92. [PMID: 10948101 PMCID: PMC101689 DOI: 10.1128/iai.68.9.4884-4892.2000] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A multivalent live oral vaccine against both Shigella spp. and enterotoxigenic Escherichia coli (ETEC) is being developed based on the hypothesis that protection can be achieved if attenuated shigellae express ETEC fimbrial colonization factors and genetically detoxified heat-labile toxin from a human ETEC isolate (LTh). Two detoxified derivatives of LTh, LThK63 and LThR72, were engineered by substitution-serine to lysine at residue 63, or lysine to arginine at residue 72. The genes encoding these two derivatives were cloned separately on expression plasmids downstream from the CFA/I operon. Following electroporation into S. flexneri 2a vaccine strain CVD 1204, coexpression of CFA/I and LThK63 or LThR72 was demonstrated by Western blot analysis, GM(1) binding assays, and agglutination with anti-CFA/I antiserum. Hemagglutination and electron microscopy confirmed surface expression of CFA/I. Guinea pigs immunized intranasally on days 0 and 15 with CVD 1204 expressing CFA/I and LThK63 or LThR72 exhibited high titers of both serum immunoglobulin G (IgG) and mucosal secretory IgA anti-CFA/I; 40% of the animals produced antibodies directed against LTh. All immunized guinea pigs also produced mucosal IgA (in tears) and serum IgG anti-S. flexneri 2a O antibodies. Furthermore, all immunized animals were protected from challenge with wild-type S. flexneri 2a. This prototype Shigella-ETEC hybrid vaccine demonstrates the feasibility of expressing multiple ETEC antigens on a single plasmid in an attenuated Shigella vaccine strain and engendering immune responses against both the heterologous antigens and vector strain.
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Affiliation(s)
- H Koprowski
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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Trachman JD, Maas WK. Temperature regulation of heat-labile enterotoxin (LT) synthesis in Escherichia coli is mediated by an interaction of H-NS protein with the LT A-subunit DNA. J Bacteriol 1998; 180:3715-8. [PMID: 9658020 PMCID: PMC107345 DOI: 10.1128/jb.180.14.3715-3718.1998] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/1998] [Accepted: 05/11/1998] [Indexed: 02/08/2023] Open
Abstract
Protein and mRNA levels of heat-labile enterotoxin (LT) of Escherichia coli are highest at 37 degrees C, and they decrease gradually as temperature is decreased. This temperature effect is eliminated in an Hns- mutant. Deletion of portions of DNA coding for the LT A subunit also results in an increase in LT expression at low temperatures, suggesting that the H-NS protein causes inhibition of transcription at low temperatures by interacting with the LT A-subunit DNA. The region that interacts with H-NS is referred to as the downstream regulatory element (DRE). Plasmids in an hns strain from which the DRE has been deleted still produce elevated levels of LT at 18 degrees C, suggesting that intact DRE is not required for transcription from the LT promoter.
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Affiliation(s)
- J D Trachman
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
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Okamoto K, Baba T, Yamanaka H, Akashi N, Fujii Y. Disulfide bond formation and secretion of Escherichia coli heat-stable enterotoxin II. J Bacteriol 1995; 177:4579-86. [PMID: 7642482 PMCID: PMC177220 DOI: 10.1128/jb.177.16.4579-4586.1995] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The Escherichia coli heat-stable enterotoxin II (STII) is a typical extracellular toxin consisting of 48 amino acid residues, of which 4 are cysteine. There are two disulfide bonds, one between Cys-10 and Cys-48 and one between Cys-21 and Cys-36. We examined the involvement of DsbA in the formation of the disulfide bonds of STII and the role of each in the secretion of STII. A dsbA mutant was transformed with a plasmid harboring the STII gene, and STII was not detected either in the cells or in the culture supernatant. Reducing the level of STII brought about the dsbA mutation restored by introducing the wild-type dsbA gene into the mutant strain. These results showed that DsbA is involved in forming the disulfide bonds of STII and that STII without these disulfide bonds is degraded during secretion. We substituted these four cysteine residues in vivo by oligonucleotide-directed site-specific mutagenesis. The amino acid sequence of the purified STII (C48S) and pulse-chase studies revealed that two intermolecular disulfide bonds must be formed to be efficiently secreted and that cleavage between amino acid residues 14 and 15 is probably the first step in the proteolytic degradation of STII.
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Affiliation(s)
- K Okamoto
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Japan
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Prasad R, Chopra AK, Chary P, Peterson JW. Expression and characterization of the cloned Salmonella typhimurium enterotoxin. Microb Pathog 1992; 13:109-21. [PMID: 1453924 DOI: 10.1016/0882-4010(92)90071-u] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Earlier, our laboratory reported the cloning of a chromosomally encoded cholera toxin (CT)-like enterotoxin gene from Salmonella typhimurium Q1 into pBR322. Cell lysates from the plasmid clone pC1, containing a 4.8 kb EcoR1 DNA fragment from Salmonella, caused elongation of Chinese hamster ovary (CHO) cells and this biologic activity was neutralized by anti-CT. However, this cloned gene product did not elicit fluid secretion in the rabbit intestinal loop (RIL) model, because of poor expression. We report here, subcloning of a 4.8 kb EcoRI and a 2.7 kb HindIII/Eco Rl fragment into a high expression T7 RNA polymerase/promoter system. Cell lysates from these clones elicited fluid secretion in the RIL model, caused firm induration in rabbit skin and elongated CHO cells. These biological activities were neutralized by anti-CT. SDS-PAGE and subsequent fluorographic analysis of Escherichia coli, harboring recombinant plasmids in a T7 expression system, revealed the presence of two prominent 35S-labeled polypeptides of 25 and 12 kDa, which were immunoprecipitated with anti-CT. The enterotoxin appeared to be 125 kDa in size, based on chromatography on a P-300 column, had a pl of 6.6 to 6.8, and was heat-labile (60 degrees C/5 min). Unlike cloned CT and heat-labile enterotoxin (LT-l), which were localized in the periplasm, the Salmonella enterotoxin was cytoplasmic in nature.
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Affiliation(s)
- R Prasad
- Center for Molecular Science, University of Texas Medical Branch, Galveston 77555-1019
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Bhadra RK, Biswas T, Pal SC, Takeda T, Nair GB. A polyclonal-monoclonal antibody based sensitive sandwich enzyme linked immunosorbent assay for specific detection of cholera toxin. ZENTRALBLATT FUR BAKTERIOLOGIE : INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY 1991; 275:467-73. [PMID: 1755920 DOI: 10.1016/s0934-8840(11)80167-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A sensitive sandwich enzyme-linked immunosorbent assay (ELISA) for specific detection of prototype cholera toxin (CT) elaborated by Vibrio cholerae serovar O1 has been developed. The use of a high affinity monoclonal antibody (MAb) for capturing of CT epitopes permitted a high efficiency. Using this ELISA, we sought in vitro production of CT from clinical strains of V. cholerae O1, Non-O1 and from LT-producing E. coli. All culture supernatants of V. cholerae O1 were positive for CT whereas V. cholerae non-O1 and LT producing E. coli were found negative for CT. This ELISA will be particularly useful in specifically designed studies where detection of CT and not of related labile toxins is mandatory.
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Affiliation(s)
- R K Bhadra
- National Institute of Cholera and Enteric Diseases, Beliaghata, Calcutta, India
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Rahman H, Singh VB, Sharma VD, Harne SD. Coagglutination test for rapid detection of Salmonella enterotoxin. ZENTRALBLATT FUR BAKTERIOLOGIE : INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY 1991; 275:303-11. [PMID: 1741910 DOI: 10.1016/s0934-8840(11)80293-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The Staphylococcal Coagglutination (CoA) test using Staphylococcus aureus (Cowan type-1) cells coated with antiserum against purified Salmonella enterotoxin was standardized and carried out to screen Salmonella serotypes for their enterotoxigenicity. Of the 101 cell-free culture supernatants from an equal number of Salmonella strains belonging to 15 different serotypes tested, 76 were found to be enterotoxigenic. All of the 24 strains which gave positive reactions in the rabbit ligated ileal loop test were also positive with this test. As little as 7.5 ng of purified Salmonella enterotoxin could be detected by the CoA test. The presence of enterotoxin in polymyxin B extract of cells and cell-free preparation of a S. typhimurium strain was detected as early as after 1.5 and 3.0 h of incubation, respectively. Besides the test standardized with the antiserum to purified V. cholerae toxin (CT) could detect purified toxin in a quantity as little as 5.0 ng and also enterotoxigenicity in an E. coli strain (LT+). The usefulness of the test as a routine, rapid and economic one for the detection of enterotoxin of Salmonella, Vibrio cholerae and E. coli is discussed.
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Affiliation(s)
- H Rahman
- Department of Microbiology and Public Health, College of Veterinary Sciences, G.B. Pant University of Agric. and Tech., Dist. Nainital (U.P.), India
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Qu ZH, Boesman-Finkelstein M, Finkelstein RA. Urea-induced release of heat-labile enterotoxin from Escherichia coli. J Clin Microbiol 1991; 29:773-7. [PMID: 1890176 PMCID: PMC269868 DOI: 10.1128/jcm.29.4.773-777.1991] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Urea induces the release of heat-labile enterotoxin (LT) from cells of LT-producing Escherichia coli strains. Optimal conditions were defined by using the checkerboard immunoblotting system. LT release was highest when E. coli cells were incubated in 8 M urea, pH 8.0, at 37 degrees C in a water bath for 30 min. Urea was more effective than polymyxin B in inducing the release of LT antigen from E. coli; the activity of LT from urea-treated cells was seven times that of LT from polymyxin B-treated cells. Urea also increased the antigenic and biological reactivities of purified LT. This procedure is potentially applicable for the detection of LT-producing E. coli strains in the clinical laboratory.
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Affiliation(s)
- Z H Qu
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia 65212
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Katayama S, Ninomiya M, Minami J, Okabe A, Hayashi H. Transcriptional control plays an important role for the production of heat-labile enterotoxin in enterotoxigenic Escherichia coli of human origin. Microbiol Immunol 1990; 34:11-24. [PMID: 2182980 DOI: 10.1111/j.1348-0421.1990.tb00987.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The production of heat-labile enterotoxin (LT) in 76 strains of human enterotoxigenic Escherichia coli (ETEC) varied by a factor of 100. Three ETEC strains that differ in the levels of LT production were chosen for the cloning of LT genes (toxAB) into plasmid pBR322, and the gene structure and expression were compared in E. coli HB101. The recombinant of the low LT-producing strain produced LT at the same level as that of the moderate LT-producing strain, but that of the high-level producer continued to produce at a level 14-21 times higher than the others. The restriction maps of the coding regions of the cloned LT genes (toxAB) were identical, but the flanking regions were dissimilar. The content of LT mRNA per cell, examined by Northern blot analysis, was higher in the high producer than the others by 6 times. The promoter strengths of the recombinants were all alike. LT mRNA of the high producer was more stable than that of the moderate one by 1.3 times, but the difference was not large enough to explain the difference of the content of LT mRNA. It was shown that LT production can be controlled at a transcriptional step, and DNA structure of the flanking regions may be involved in the control of the LT gene expression.
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Affiliation(s)
- S Katayama
- Department of Microbiology, Kagawa Medical School
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Abstract
A rapid agar diffusion method for the detection of DNase production of Campylobacter jejuni, C. coli, and C. pylori was developed. A strong pink zone indicating DNA hydrolysis was seen around the wells after 20 to 24 h of aerobic incubation at 37 degrees C. Pretreatment of cells with polymyxin B, which releases the cell-associated DNase, both shortened the time needed to read positive results to 8 h and increased the zone size.
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Affiliation(s)
- M L Hänninen
- Department of Food and Environmental Hygiene, College of Veterinary Medicine, Finland
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Lee CK, Roberts A, Perrin S. Expression of pertussis toxin in Bordetella bronchiseptica and Bordetella parapertussis carrying recombinant plasmids. Infect Immun 1989; 57:1413-8. [PMID: 2707851 PMCID: PMC313292 DOI: 10.1128/iai.57.5.1413-1418.1989] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Pertussis toxin is produced only by strains of Bordetella pertussis. Cloned genes encoding pertussis toxin from B. pertussis were transferred into Bordetella bronchiseptica and Bordetella parapertussis by conjugation. These transconjugants expressed pertussis toxin at levels comparable to those expressed by B. pertussis. The toxin made by these strains was biologically active in the Chinese hamster cell clumping assay, contained all five subunits, and was mostly periplasmic. Toxin expression appeared to be modulated in the same way as are the vir-regulated genes of B. pertussis. Introduction of these plasmids into B. pertussis failed to produce hypertoxigenic strains. Instead, these transconjugants underwent plasmid loss, gene deletions, or conversion to the avirulent phase.
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Affiliation(s)
- C K Lee
- Biologic Laboratories, Center for Disease Control of the Massachusetts Department of Public Health, Boston 02130
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Kluftinger JL, Lutz F, Hancock RE. Pseudomonas aeruginosa cytotoxin: periplasmic localization and inhibition of macrophages. Infect Immun 1989; 57:882-6. [PMID: 2492976 PMCID: PMC313193 DOI: 10.1128/iai.57.3.882-886.1989] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Pseudomonas aeruginosa cytotoxin has been isolated previously from cell autolysates. Both purified cytotoxin and periplasmic contents (osmotic shock fluid) cross-reacted on Western immunoblots with antibodies specific for cytotoxin. In addition, both preparations caused a significant reduction in antibody-mediated phagocytosis of P. aeruginosa M2 by mouse macrophage cell line P388D1. Phagocytosis was restored in each case on preincubation of cytotoxin or periplasmic contents with anti-cytotoxin serum. Both cytotoxin and periplasmic contents caused depolarization of the P388D1 cell membrane, as demonstrated with a polarization-sensitive fluorescent probe. Similar correlations were not observed for other P. aeruginosa cell fractions or for osmotic shock fluid from Escherichia coli C600. These data indicate that P. aeruginosa cytotoxin is localized in the periplasm and has the potential to inhibit macrophage-mediated phagocytosis, possibly by perturbing ion gradients across the macrophage plasma membrane.
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Affiliation(s)
- J L Kluftinger
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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TAKASHI K, FLUITA I, KOBARI K. Effects of Short Chain Fatty Acids on the Production of Heat-Labile Enterotoxin from Enterotoxigenic Escherichia coli. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/s0021-5198(19)42434-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Foucaud-Gamen J, Le Noc P, Renaudet J, Guimet J. Etude de six tests de detection de l'enterotoxine tl d'E. coli dont la sensibilite. Med Mal Infect 1988. [DOI: 10.1016/s0399-077x(88)80196-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Said AC, Serafim MB, Pestana de Castro AF. Evaluation of the Biken test to detect heat-labile (LT) enterotoxin produced by porcine and human Escherichia coli strains. ANNALES DE L'INSTITUT PASTEUR. MICROBIOLOGY 1987; 138:657-66. [PMID: 3331294 DOI: 10.1016/0769-2609(87)90144-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Fifty-seven strains of enterotoxigenic Escherichia coli isolated from humans and pigs and producing thermolabile (LT) enterotoxin were used to ascertain the efficiency of the Biken test compared to the passive immune haemolysis test (PIH), considered as very sensitive for detecting that enterotoxin. The two assays were carried out using anti-porcine (anti-LTp), anti-human (anti-LTh), anti-cholera toxin (anti-CT) and anti-choleragenoid (anti-Cg) antisera. Our results showed that the Biken test was very irregular, with many false-negative results. Positive results (ranging from 78.9 to 22.8) were dependent upon the antiserum used. Conversely, the PIH test was much more efficient in the detection of LT, since 100% of the LT+ strains were positive in this test whatever the antiserum used.
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Affiliation(s)
- A C Said
- Department of Microbiology and Immunology, University of Campinas, São Paulo, Brazil
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22
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Abstract
Pertussis toxin (PT), the major virulence factor of Bordetella pertussis, is composed of five different subunits whose genes are organized as an operon. We report the mapping of the promoter region of the PT operon and show that this promoter is only weakly active in Escherichia coli. Bordetella parapertussis and Bordetella bronchiseptica, which do not produce any PT, are shown to have a weaker promoter sequence for this operon and not to produce any detectable PT mRNA. We show that transcription of the PT operon in B. pertussis was constant throughout until the late stationary phase, when transcription significantly decreased. Analysis of the transposon Tn5 mutant BP347 showed that the product of the vir locus was required for transcription of the PT operon. Characterization of the Tn5 mutant BP356 showed that subunit S3 was required for the release of PT into the extracellular medium.
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23
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Ricci LC, de Castro AF. Indirect haemagglutination test for the detection of thermolabile (LT) enterotoxin from Escherichia coli. Med Microbiol Immunol 1986; 175:251-60. [PMID: 3526105 DOI: 10.1007/bf02123733] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
An indirect haemagglutination test (IH) for the detection of enterotoxigenic E. coli (LT) was developed. Twenty-five enterotoxigenic E. coli (ETEC) from human and porcine diarrhoea and from river water were examined. The described IH test was more specific and sensitive than the passive immune haemolysis test (PIH).
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Bongaerts GP, Bruggeman-Ogle KM, Mouton RP. Improvements in the microtitre GM1 ganglioside enzyme-linked immunosorbent assay for Escherichia coli heat-labile enterotoxin. THE JOURNAL OF APPLIED BACTERIOLOGY 1985; 59:443-9. [PMID: 3910634 DOI: 10.1111/j.1365-2672.1985.tb03344.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A variant of the microtitre GM1-ELISA for Escherichia coli heat-labile enterotoxin was studied. The test was improved by both reducing the assay time from 2 1/2 d to 8 h and by determining the most appropriate GM1 coating concentration. Coating the plates with greater than or equal to 3 micrograms of GM1/ml yielded a maximal sensitivity and ensured a linear relationship between the enterotoxin concentration and the extinction observed when using the final assay-procedure. Thus an optimal accuracy was obtained. This ELISA was 4- to 8-times more sensitive than the Vero cell monolayer assay. The sensitivity of this ELISA and of the chinese hamster ovary cell monolayer assay were identical.
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25
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Karmali MA, Petric M, Lim C, Cheung R, Arbus GS. Sensitive method for detecting low numbers of verotoxin-producing Escherichia coli in mixed cultures by use of colony sweeps and polymyxin extraction of verotoxin. J Clin Microbiol 1985; 22:614-9. [PMID: 3908473 PMCID: PMC268478 DOI: 10.1128/jcm.22.4.614-619.1985] [Citation(s) in RCA: 124] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
High titers of Verotoxin (VT) were released from cell pellets of VT-producing Escherichia coli (VTEC; corresponding to E. coli strains producing "high" levels of Shiga-like toxin) after incubation in polymyxin B (0.1 mg/ml) for 30 min at 37 degrees C. Maximal titers of polymyxin-releasable VT occurred in cells obtained from 5-h Penassay broth cultures and were up to eightfold higher than the peak culture supernatant VT titers which occurred in 8-h cultures. Polymyxin-releasable cell extracts of 5-h broth cultures inoculated with mixtures of VT-positive (VT+) and VT-negative strains had easily detectable VT titers when the proportion of VT+ cells in the mixture was about 1.0%, but culture supernatants were negative for VT even when this proportion was 20%. The results were the same whether the initial inoculum consisted of broth culture mixtures of VT+ and VT-negative strains or colony sweeps (loopfuls of confluent bacterial growth) taken from solid plate media previously inoculated with the broth mixtures. In a clinical study, 80 stool cultures from patients with hemolytic uremic syndrome and family contacts with diarrhea were tested for free fecal VT, VT in polymyxin extracts of colony sweeps (VT/PECS), and VTEC (examination of 20 separate E. coli colonies from primary media for VT production). Of the 80 samples, 40 were positive for at least one of these three tests; all 40 were positive for free fecal VT, and 20 of these were positive for VT/PECS. VTEC (as few as 1 colony out of 20) were only isolated from 14 of the 20 cultures that were positive for VT/PECS. In six cases, the VT/PECS was positive even when none of 20 colonies tested were VT+, suggesting that the procedure was able to detect a proportion of VTEC that was less than one in 20(5%). We conclude that the VT/PECS method is highly sensitive for detecting low concentrations of VTEC in stools and provides a rapid method for screening out stools that are negative for VTEC. The technique should also be of value in epidemiological studies for detecting low numbers of VTEC in animal feces, foods, and environmental samples.
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26
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Turnbull PC, Lee JV, Miliotis MD, Still CS, Isaäcson M, Ahmad QS. In vitro and in vivo cholera toxin production by classical and El Tor isolates of Vibrio cholerae. J Clin Microbiol 1985; 21:884-90. [PMID: 4008618 PMCID: PMC271811 DOI: 10.1128/jcm.21.6.884-890.1985] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A comparative study was carried out on the in vitro production of cholera toxin by 19 Vibrio cholerae El Tor isolates from patients with cholera in South Africa, one El Tor isolate from a patient in Malawi (a country approximately 1000 km north-northeast of South Africa), 6 El Tor and 12 classical type isolates from patients in Bangladesh, and 5 culture collection classical strains. Identical phage types and indistinguishable toxigenicities among the South African and Malawi V. cholerae, representing isolations obtained over a 10-year period, indicated that essentially a single strain was involved in the cholera of these regions. Similarly, phage typing and toxin profiles indicated that the 12 classical and 6 El Tor V. cholerae cultures in Bangladesh, all isolated in November 1983, represented just two strains. As assessed by titrations in Y-1 mouse adrenal and Chinese hamster ovary cell lines, the general order of toxigenicities was Bangladesh and culture collection classical greater than Bangladesh El Tor greater than southern African El Tor. The African isolates consistently gave rise to very low titers. Their relative reluctance to produce the toxin in vitro compared with the culture collection classical strains, particularly strain 569B, was confirmed by rocket electrophoresis. In somewhat of a contrast, maximum in vivo titers in rice water stools from cholera patients in South Africa and from both classical and El Tor type cholera patients in Bangladesh were essentially equal. It is postulated that under the continuous culture conditions that occur in vivo, cholera toxin concentrations can accumulate to a maximum level, depending on the rate of purging by the diarrheal fluid rather than the toxigenicity of the infecting stain. The relevance of these findings to the relative severities of classical and El Tor types of cholera is discussed.
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Srivastava R, Khan AA, Srivastava BS. Immunological detection of cloned antigenic genes of Vibrio cholerae in Escherichia coli. Gene 1985; 40:267-72. [PMID: 3913626 DOI: 10.1016/0378-1119(85)90049-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Antibodies have been used as probe to detect cloned genes coding for toxin and surface antigens of Vibrio cholerae El Tor strain KB207. EcoRI-digested chromosomal DNA of KB207 was cloned in plasmid pBR325 and transformed in Escherichia coli HB101(lambda cI857). Transformants were grown at 32 degrees C on plates containing antibodies. Lysogen was induced at 42 degrees C to release expressed antigens. Antigen-antibody reaction produced a halo around positive clones.
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Seltmann G, Beer W, Voigt W, Wolter EJ, Grahlow WD. [Cell wall proteins of Escherichia coli: a substance resembling the thermolabile enterotoxin (LT)]. J Basic Microbiol 1985; 25:57-68. [PMID: 3889273 DOI: 10.1002/jobm.3620250116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
In ultrasonic extracts of all 19 investigated non-enterotoxigenic E. coli strains a substance (LTLS) could be detected reacting positively in all tests which are commonly used to detect specifically E. coli thermolabile enterotoxin (LT). Culture supernatants of these strains in general did not contain LTLS in detectable amounts. LTLS can be found in the whole cell, however, the membrane fraction contains the highest quantities. Released LTLS appears mainly aggregated with components of the cell wall, especially with lipopolysaccharides. This fact in combination with the very low quantities produced by the bacteria renders very difficult purification of LTLS.
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Construction of a conjugative plasmid with potential use in vaccines against heat-labile enterotoxin. Infect Immun 1985; 47:5-10. [PMID: 2981199 PMCID: PMC261447 DOI: 10.1128/iai.47.1.5-10.1985] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
A conjugative plasmid with potential usefulness for vaccine strains was constructed. In the first step, a 5.9-kilobase DNA segment containing the two loci for the A and B subunits of heat-labile enterotoxin with a mutation in the gene for the A subunit was joined to the cloning vehicle pGA22, generating the nonconjugative plasmid pPMC4 with genes for resistance to tetracycline and chloramphenicol. In the second step, a segment of pPMC4 containing the genes for the A and B subunits, the gene for chloramphenicol resistance, and the replication genes of pGA22 was ligated to the genes for conjugal transfer of the F plasmid, generating the 54.9-kb plasmid pPMC5. Eleven porcine Escherichia coli isolates were tested as recipients for pPMC4 and pPMC5. For pPMC4, transformation and mobilization with a conjugative R plasmid were used to effect plasmid transfer. Only 1 of the 11 strains acted as a recipient in transformation. Mobilization with the R plasmid occurred with two strains, but the plasmids were altered during transfer. In contrast, pPMC5 was transferred with high frequency and unaltered to 9 of the 11 E. coli strains. Transconjugants from these nine matings produced high titers of the B subunit and no active heat-labile enterotoxin. Plasmid pPMC5 was stable in three porcine E. coli strains tested; plasmid pPMC4 was somewhat less stable in these strains. The method we describe for the construction of conjugative chimeric plasmids offers an opportunity for introducing genes with potential for immunization into bacterial strains that are suitable for colonizing the appropriate host sites.
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31
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DiRienzo JM, Tsai CC, Shenker BJ, Taichman NS, Lally ET. Monoclonal antibodies to leukotoxin of Actinobacillus actinomycetemcomitans. Infect Immun 1985; 47:31-6. [PMID: 3965404 PMCID: PMC261455 DOI: 10.1128/iai.47.1.31-36.1985] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Hybridoma cell lines which produce monoclonal antibodies to a leukotoxin from Actinobacillus actinomycetemcomitans were prepared. The monoclonal antibodies were selected for their ability to neutralize the cytotoxic activity of the leukotoxin and recognize the toxin on nitrocellulose blots. The antibodies belonged to either the immunoglobulin G1 (IgG1) or IgG2 subclass and differed in their ability to bind to the leukotoxin on nitrocellulose blots. However, only slight differences in neutralization titers were observed. Use of the monoclonal antibodies revealed that polymyxin B-extracted or osmotic shock-released leukotoxin could be separated into several high-molecular-weight polypeptides by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunoblot analysis with the monoclonal antibodies also demonstrated that the leukotoxin was present in eight oral strains of A. actinomycetemcomitans that had been previously classified by a biological assay as leukotoxic. The availability of these monoclonal antibodies should facilitate and expand studies concerning the role of the leukotoxin in the pathogenicity of A. actinomycetemcomitans.
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Andro T, Chambost JP, Kotoujansky A, Cattaneo J, Bertheau Y, Barras F, Van Gijsegem F, Coleno A. Mutants of Erwinia chrysanthemi defective in secretion of pectinase and cellulase. J Bacteriol 1984; 160:1199-203. [PMID: 6389513 PMCID: PMC215846 DOI: 10.1128/jb.160.3.1199-1203.1984] [Citation(s) in RCA: 148] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Erwinia chrysanthemi produced several pectate lyases (EC 4.2.2.2) and endocellulases (EC 3.2.1.4) which were largely secreted into the culture medium. Mutants deficient in the secretion mechanism for these enzymes were obtained by chemical and insertion mutagenesis. Further study of one such mutant revealed that both enzyme activities were retained simultaneously within the periplasmic space.
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33
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Hirst TR, Sanchez J, Kaper JB, Hardy SJ, Holmgren J. Mechanism of toxin secretion by Vibrio cholerae investigated in strains harboring plasmids that encode heat-labile enterotoxins of Escherichia coli. Proc Natl Acad Sci U S A 1984; 81:7752-6. [PMID: 6393126 PMCID: PMC392230 DOI: 10.1073/pnas.81.24.7752] [Citation(s) in RCA: 95] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
A genetically engineered Vibrio cholerae strain from which the cholera toxin genes had previously been deleted was used as a host in which to study the expression and secretion of related toxins and their subunits. Recombinant plasmids encoding heat-labile enterotoxins (LTs) from Escherichia coli of human and porcine origin were expressed in the V. cholerae host, and this resulted in the secretion of the LTs into the extracellular milieu. The secreted LTs were isolated and it was found that the A subunits of human and porcine LT were "unnicked" polypeptides, which indicates that nicking is not obligatory for toxin secretion. V. cholerae strains were also constructed that harbored plasmids encoding either the A or the B subunits of human LT (A+B-, or A-B+). Approximately 90% of the B subunits were secreted from the A-B+ strain, while all of the A subunits expressed by the A+B- strain remained cell associated. This implies that strains synthesizing both subunits assemble the A and B subunits prior to their secretion. We propose that the entry of the toxin into the secretory step of the export pathway is mediated by a secretory apparatus that recognizes structural domains within the B subunit of LT.
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Germani Y, Begaud E, Dassy B, Legonidec G, Guesdon J. Méthode de détection et de dosage de l'entérotoxine thermolabile de Escherichia coli par une technique immunoenzymatique sur un nouveau support de polystyrène adapté en trousse autonome. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0769-2609(84)80097-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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35
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Production de l'entérotoxine thermolabile de Escherichia coli sur milieu synthétique en vue de son dosage sur culture de cellules vero. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0769-2609(84)80096-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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36
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Kabir S, Ahmad N, Ali S. Neuraminidase production by Vibrio cholerae O1 and other diarrheagenic bacteria. Infect Immun 1984; 44:747-9. [PMID: 6373618 PMCID: PMC263689 DOI: 10.1128/iai.44.3.747-749.1984] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Vibrio cholerae O1 strains belonging to both biotypes (classical and El Tor) and both serotypes (Ogawa and Inaba) produced neuraminidase which was released rather than cell bound. Classical strains made more neuraminidase than did El Tor strains. About one-third of V. cholerae non-O1 strains and one-fourth of Aeromonas hydrophila strains were neuraminidase positive. Strains of enterotoxigenic Escherichia coli, Vibrio parahaemolyticus, and Shigella spp. did not produce detectable neuraminidase.
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Dosage des anticorps de lapin anti-entérotoxine thermolabile de Escherichia coli par une technique immunoenzymatique. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/s0769-2625(84)81158-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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38
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Tsai CC, Shenker BJ, DiRienzo JM, Malamud D, Taichman NS. Extraction and isolation of a leukotoxin from Actinobacillus actinomycetemcomitans with polymyxin B. Infect Immun 1984; 43:700-5. [PMID: 6319288 PMCID: PMC264356 DOI: 10.1128/iai.43.2.700-705.1984] [Citation(s) in RCA: 167] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A leukotoxin from Actinobacillus actinomycetemcomitans was isolated by a procedure that includes polymyxin B extraction, ion-exchange chromatography, and gel filtration chromatography. The procedure resulted in the recovery of 48% of the toxin with a 99-fold increase in specific activity. The isolated toxin has a molecular mass of 180,000 daltons by gel filtration and 115,000 daltons by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It retains all the major biological characteristics previously documented for crude leukotoxin preparations, including susceptibility to heat and proteolytic enzymes and neutralization by sera from patients with juvenile periodontitis. The isolated leukotoxin destroys human but not rat or guinea pig polymorphonuclear leukocytes and has no apparent effect on human erythrocytes. The availability of the A. actinomycetemcomitans leukotoxin should facilitate studies on its chemistry and mode of action as well as its role in the pathogenesis of human periodontal disease.
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Hirst TR, Randall LL, Hardy SJ. Cellular location of heat-labile enterotoxin in Escherichia coli. J Bacteriol 1984; 157:637-42. [PMID: 6363391 PMCID: PMC215294 DOI: 10.1128/jb.157.2.637-642.1984] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We demonstrated that both the A and B subunits of heat-labile enterotoxin from Escherichia coli are located in the periplasm. The toxin was shown to form aggregates in Tris-EDTA buffers which are routinely used for isolating membranes. The aggregates pellet upon centrifugation, and this may explain why several previous investigators have concluded that enterotoxin is associated with membranes.
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40
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Ricci LC, Fontes CF, Siqueira PS, Pestana de Castro AF. Storage of Escherichia coli thermolabile enterotoxin on filter papers for assay by immune haemolysis reactions. Med Microbiol Immunol 1984; 172:243-8. [PMID: 6371466 DOI: 10.1007/bf02123719] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thermolabile (LT) enterotoxin was prepared from stationary and shaken cultures of enterotoxigenic Escherichia coli (ETEC) grown in casamino acids-yeast extract medium and dried onto filter discs. These were then examined by a modification of the single radial immune haemolysis (SRIH) test. It was observed that LT antigenicity, as detected by this test, remained unaltered for as long as 30 days at room temperature.
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41
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Ristaino PA, Levine MM, Young CR. Improved GM1-enzyme-linked immunosorbent assay for detection of Escherichia coli heat-labile enterotoxin. J Clin Microbiol 1983; 18:808-15. [PMID: 6355161 PMCID: PMC270911 DOI: 10.1128/jcm.18.4.808-815.1983] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Previously described GM1 ganglioside enzyme-linked immunosorbent assays (GM1-ELISA) for the detection of Escherichia coli heat-labile enterotoxin (LT) showed sensitivity equal to the Y-1 adrenal cell assay when anti-LT (a reagent not commercially available) was used. However, when antitoxin to immunologically related (commercially available) cholera toxin was substituted, a marked loss in sensitivity occurred. We modified the GM1-ELISA that employed anti-cholera toxin to make it comparable in sensitivity to the Y-1 adrenal cell assay. When five media commonly used for LT production were compared, Mundell's Casamino Acids medium was shown to be significantly superior. Lincomycin (45 micrograms/ml) added to E. coli cultures significantly increased net optical densities in the GM1-ELISA, a direct measure of the amount of LT. Treatment of broth cultures or bacterial cell pellets with polymyxin B or extension of culture time to 48 h also significantly increased net optical density by allowing enhanced release of periplasmic LT. A major innovation involved the direct culture of E. coli strains in GM1-coated wells of microtiter plates followed by ELISA. This direct culture method GM1-ELISA (DCM-GM1-ELISA) saved not only assay time, but also materials and reagents. The net optical densities that result from this assay allow the test to be read visually without a spectrophotometer. Three independent observers read plates with E. coli tested by DCM-GM1-ELISA. Thirty-four of 35 adrenal cell-positive strains (97% sensitivity) and 30 of 30 LT-negative control E. coli strains (100% specificity) were identified by all three observers reading coded plates. The DCM-GM1-ELISA provides a simple, practical and efficient assay for LT for less sophisticated laboratories.
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42
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Morgan DR, DuPont HL, Wood LV, Ericsson CD. Comparison of methods to detect Escherichia coli heat-labile enterotoxin in stool and cell-free culture supernatants. J Clin Microbiol 1983; 18:798-802. [PMID: 6355159 PMCID: PMC270909 DOI: 10.1128/jcm.18.4.798-802.1983] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We compared the standard Y-1 adrenal cell (YAC) assay for heat-labile enterotoxin (LT) with newer rapid and economical immunological methods of detection. Stool samples were collected from 164 acutely ill American students in Guadalajara, Mexico. Supernatants were prepared from each stool. Stools were cultured for Escherichia coli by standard techniques. Individual E. coli-like colonies were examined for LT production by the Biken assay. Culture supernatants and stool supernatants were assayed for the presence of LT by the YAC assay, counterimmunoelectrophoresis, and enzyme-linked immunosorbent assay (ELISA). Standard YAC assays of culture supernatants revealed that 40 of the 164 specimens (24%) were LT positive. Counterimmunoelectrophoresis detected 60% and ELISA detected 65% of the 40 known positives when culture supernatants were used. The Biken assay detected 35% of the 40 known positives. With stool supernatants, the YAC assay detected only 18% of the known positives, counterimmunoelectrophoresis detected 60%, and ELISA detected 90%. In addition, ELISA detected 13 LT-positive stool supernatants not detected by the YAC assay of culture supernatants. The ELISA in which stool supernatants are used may be a useful method to detect LT.
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Abstract
Release of Shiga toxin from Shigella dysenteriae 1 was found to occur after exposure to polymyxin B. The amount of toxin released was dependent on both the polymyxin concentration and time of incubation. An immunoblot characterization of the Shiga toxin released by polymyxin treatment demonstrated that it is electrophoretically similar to purified Shiga toxin and to Shiga toxin present in crude bacterial sonicates of S. dysenteriae 1 cells.
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Donohue-Rolfe A, Keusch GT. Shigella dysenteriae 1 cytotoxin: periplasmic protein releasable by polymyxin B and osmotic shock. Infect Immun 1983; 39:270-4. [PMID: 6295958 PMCID: PMC347936 DOI: 10.1128/iai.39.1.270-274.1983] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Treatment of Shigella dysenteriae 1 either with the antibiotic polymyxin B or by osmotic shock resulted in the release of 80 to 90% of the cytotoxin activity of the organism. Under the conditions employed, the release of toxin activity was accompanied by the appearance of a periplasmic enzyme, 5'-nucleotidase. There was no significant release of cytoplasmic contents, assessed by measurement of glucose-6-phosphate dehydrogenase activity. The release of cytotoxin and 5'-nucleotidase by polymyxin B were both dependent on the duration of incubation with, and the concentration of, the antibiotic. In terms of specific activity (cytotoxin activity per milligram of protein), the polymyxin B and osmotic shock extracts were 20- to 30-fold more active than crude toxin preparation derived from a whole-cell lysate. The data strongly support a periplasmic location for Shiga cytotoxin and the utility of the polymyxin B extraction to obtain starting material for toxin purification.
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Yano T, Oliveira MS, Fontes CF, de Almeida AC, de Castro AF. Detection of heat-labile (LT) enterotoxin of enterotoxigenic Escherichia coli by the radial immune hemolysis test: a modification for clinical use. Med Microbiol Immunol 1982; 171:171-8. [PMID: 6761565 DOI: 10.1007/bf02123625] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
An adaptation for clinical purposes of a radial immune hemolysis test for the detection of the heat-labile (LT) enterotoxin of the enterotoxigenic Escherichia coli is described. The results correlated well with those from Vero cell assay and the passive immune hemolysis test. Because the test is easy, relatively cheap, and as sensitive as other standard procedures, for LT detection, it is particularly suitable for less-equipped laboratories. Also, a large number of E. coli strains may be examined daily by this technique.
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Epidémie de diarrhées à Escherichia coli entérotoxinogènes dans un service hospitalier à Strasbourg. Med Mal Infect 1982. [DOI: 10.1016/s0399-077x(82)80096-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Gennaro ML, Greenaway PJ, Broadbent DA. The expression of biologically active cholera toxin in Escherichia coli. Nucleic Acids Res 1982; 10:4883-90. [PMID: 6290992 PMCID: PMC320838 DOI: 10.1093/nar/10.16.4883] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Chromosomal DNA from Vibrio cholerae El Tor strain 1621 was digested with Hind III and the products fractionated by centrifugation through a sucrose gradient. A 15kb fragment containing the toxin gene of V. cholerae was identified by its homology with the heat labile toxin (LT) gene of toxigenic E. coli. This fragment was cloned in E. coli using pAT153 and subsequently characterised by digestion with different restriction endonucleases. Sequences homologous to the LT gene were identified by hybridisation and then sub-cloned using either pAT153 or pACYC184. Expression of the cloned CT gene in E. coli was detected using both cell culture and ELISA assays. One recombinant plasmid coded for the synthesis of an immunologically active but biologically inactive derivative of CT.
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Fontes CF, Ricci LC, Oliveira MS, Gatti MS, Pestana de Castro AF. Evaluation of a defined medium for the production of both thermolabile (LT) and thermostable (ST) enterotoxins of Escherichia coli. Med Microbiol Immunol 1982; 171:43-51. [PMID: 6750340 DOI: 10.1007/bf02122706] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The production of thermolabile (LT) enterotoxin was compared in a defined medium reported by Staples et al. (SAG medium) for the production of thermostable (ST) enterotoxin and the Casamino acids-Yeast extract (CAYE) medium. Aliquots were drawn frum cultures of an enterotoxigenic (LT+, ST+) E. coli in both media at different times, growth curves were plotted, and culture filtrates tested for toxin activity. Levels of LT and ST and in the SAG showed that it is as suitable as CAYE for the production of LT. The addition of either glucose (1%) or lincomycin (90 microgram/ml) to SAG medium increased LT levels, but no synergistic effort could be observed if both substances were added concomitantly. Cultures in SAG medium incubated stationarily for 72 h at 37 degrees C yielded more LT than shaking cultures incubated similarly.
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Abstract
The results of studies with cell-free extracts and culture supernatant fluids of Vibrio fluvialis (a recently recognized, potential enteric pathogen for humans) grown in the absence and presence of lincomycin indicated that the bacterium could produce (i) a factor which causes CHO cell elongation (CEF) similar to that elicited by V. cholerae enterotoxin and by the heat-labile enterotoxin of Escherichia coli, (ii) cytolysin(s) active against erythrocytes, (iii) nonhemolytic, CHO cell-killing factor(s), and (iv) protease(s) active against azocasein. The CEF was heat labile and ammonium sulfate precipitable, and it had an isoelectric point (estimated by sucrose density gradient electrofocusing) and molecular weight (estimated by gel filtration) of about 5.1 and 135,000, respectively.
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