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Development of a specific cytolethal distending toxin (cdt) gene (Eacdt)-based PCR assay for the detection of Escherichia albertii. Diagn Microbiol Infect Dis 2019; 95:119-124. [PMID: 31272742 DOI: 10.1016/j.diagmicrobio.2019.04.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/30/2019] [Accepted: 04/30/2019] [Indexed: 11/21/2022]
Abstract
Many Escherichia albertii isolates, an emerging pathogen of human and birds, might have been misidentified due to the difficulty of differentiating this bacterium from Escherichia coli and Shigella spp. by routine biochemical tests, resulting in underestimation of E. albertii infections. We have developed a polymerase chain reaction (PCR) assay that targets E. albertii cytolethal distending toxin (Eacdt) genes, which include the genes previously identified as Escherichia coli cdt-II. This assay could generate a single 449-bp PCR product in each of 67 confirmed E. albertii strains but failed to produce PCR product from any of the tested non-E. albertii enteric strains belonging to 37 different species, indicating 100% sensitivity and specificity of the PCR assay. The detection limit was 10 CFU per PCR tube and could detect 105 CFU E. albertii per gram of spiked healthy human stool. The Eacdt gene-based PCR could be useful for simple, rapid, and accurate detection and identification of E. albertii.
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Somroop S, Hatanaka N, Awasthi SP, Okuno K, Asakura M, Hinenoya A, Yamasaki S. Campylobacter upsaliensis isolated from dogs produces high titer of cytolethal distending toxin. J Vet Med Sci 2017; 79:683-691. [PMID: 28202878 PMCID: PMC5383197 DOI: 10.1292/jvms.16-0654] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Cytolethal distending toxin (CDT) consisting of CdtA, CdtB and CdtC has been reported to be a possible virulence factor of campylobacters including
Campylobacter upsaliensis. In our previous study, the cdtB gene-based PCR-restriction fragment length polymorphism (RFLP)
assay for detection and differentiation of 7 Campylobacter species yielded 3 different RFLP patterns (Cu-I to Cu-III). In this study, entire
cdt (Cucdt) genes of each pattern were sequenced to see whether there are any differences in cdt genes, its
amino acid sequences and biological activity of CuCDT. We found that all 3 representative strains harbor the entire Cucdt genes and homology
between prototype and newly determined Cucdt genes was 94 to 98% with cdtA, 93 to 94% with cdtB and 92 to 93%
with cdtC, while that between amino acids of CuCDT was 95 to 99% with CdtA, 97 to 98% with CdtB and 92 to 93% with CdtC. Furthermore, CDT
activity produced by C. upsaliensis strains was examined by cytotoxicity assay with HeLa cells. Interestingly, C. upsaliensis
produced 64 to 2,340 times higher CDT titer in comparison to other campylobacters did. In addition, Cu-III showed 64 times higher CDT titer than Cu-II, although
CDT production level was almost the same by western blotting. These data suggest that CDT produced by C. upsaliensis might contribute more to
human diseases in comparison to that produced by other campylobacters and Cu-III CDT seems to be more toxic to HeLa cells in comparison to Cu-I and Cu-II
CDTs.
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Affiliation(s)
- Srinuan Somroop
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Osaka 598-8531, Japan
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Hatanaka N, Kamei K, Somroop S, Awasthi SP, Asakura M, Misawa N, Hinenoya A, Yamasaki S. A PCR-RFLP assay to detect and type cytolethal distending toxin (cdt) genes in Campylobacter hyointestinalis. J Vet Med Sci 2017; 79:336-342. [PMID: 27916784 PMCID: PMC5326939 DOI: 10.1292/jvms.16-0263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Campylobacter hyointestinalis is considered as an emerging zoonotic pathogen. We have
recently identified two types of cytolethal distending toxin (cdt) gene in C.
hyointestinalis and designated them as Chcdt-I and Chcdt-II. In this study, we developed a
PCR-restriction fragment length polymorphism (RFLP) assay that can differentiate
Chcdt-I from Chcdt-II. When the PCR-RFLP assay was
applied to 17 other Campylobacter strains and 25
non-Campylobacter strains, PCR products were not obtained irrespective
of their cdt gene-possession, indicating that the specificity of the
PCR-RFLP assay was 100%. In contrast, when the PCR-RFLP assay was applied to 35 C.
hyointestinalis strains including 23 analyzed in the previous study and 12
newly isolated from pigs and bovines, all of them showed the presence of
cdt genes. Furthermore, a restriction digest by EcoT14-I revealed that
29 strains contained both Chcdt-I and Chcdt-II and 6
strains contained only Chcdt-II, showing 100% sensitivity. Unexpectedly,
however, PCR products obtained from 7 C. hyointestinalis strains were not
completely digested by EcoT14-I. Nucleotide sequence analysis revealed that the undigested
PCR product was homologous to cdtB but not to Chcdt-IB
or Chcdt-IIB, indicating the presence of another cdt
gene-variant. Then, we further digested the PCR products with DdeI in addition to
EcoT14-I, showing that all three cdt genes, including a possible new
Chcdt variant, could be clearly differentiated. Thus, the PCR-RFLP
assay developed in this study is a valuable tool for evaluating the Chcdt
gene-profile of bacteria.
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Affiliation(s)
- Noritoshi Hatanaka
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58, Rinkuourai-kita, Izumisano, Osaka 598-8531, Japan
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Scuron MD, Boesze-Battaglia K, Dlakić M, Shenker BJ. The Cytolethal Distending Toxin Contributes to Microbial Virulence and Disease Pathogenesis by Acting As a Tri-Perditious Toxin. Front Cell Infect Microbiol 2016; 6:168. [PMID: 27995094 PMCID: PMC5136569 DOI: 10.3389/fcimb.2016.00168] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/15/2016] [Indexed: 12/11/2022] Open
Abstract
This review summarizes the current status and recent advances in our understanding of the role that the cytolethal distending toxin (Cdt) plays as a virulence factor in promoting disease by toxin-producing pathogens. A major focus of this review is on the relationship between structure and function of the individual subunits that comprise the AB2 Cdt holotoxin. In particular, we concentrate on the molecular mechanisms that characterize this toxin and which account for the ability of Cdt to intoxicate multiple cell types by utilizing a ubiquitous binding partner on the cell membrane. Furthermore, we propose a paradigm shift for the molecular mode of action by which the active Cdt subunit, CdtB, is able to block a key signaling cascade and thereby lead to outcomes based upon programming and the role of the phosphatidylinositol 3-kinase (PI-3K) in a variety of cells. Based upon the collective Cdt literature, we now propose that Cdt is a unique and potent virulence factor capable of acting as a tri-perditious toxin that impairs host defenses by: (1) disrupting epithelial barriers; (2) suppressing acquired immunity; (3) promoting pro-inflammatory responses. Thus, Cdt plays a key role in facilitating the early stages of infection and the later stages of disease progression by contributing to persistence and impairing host elimination.
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Affiliation(s)
- Monika D Scuron
- Department of Pathology, School of Dental Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, School of Dental Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Mensur Dlakić
- Department of Microbiology and Immunology, Montana State University Bozeman, MT, USA
| | - Bruce J Shenker
- Department of Pathology, School of Dental Medicine, University of Pennsylvania Philadelphia, PA, USA
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Miller R, Wiedmann M. Dynamic Duo-The Salmonella Cytolethal Distending Toxin Combines ADP-Ribosyltransferase and Nuclease Activities in a Novel Form of the Cytolethal Distending Toxin. Toxins (Basel) 2016; 8:E121. [PMID: 27120620 PMCID: PMC4885037 DOI: 10.3390/toxins8050121] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 03/30/2016] [Accepted: 04/15/2016] [Indexed: 01/02/2023] Open
Abstract
The cytolethal distending toxin (CDT) is a well characterized bacterial genotoxin encoded by several Gram-negative bacteria, including Salmonella enterica (S. enterica). The CDT produced by Salmonella (S-CDT) differs from the CDT produced by other bacteria, as it utilizes subunits with homology to the pertussis and subtilase toxins, in place of the traditional CdtA and CdtC subunits. Previously, S-CDT was thought to be a unique virulence factor of S. enterica subspecies enterica serotype Typhi, lending to its classification as the "typhoid toxin." Recently, this important virulence factor has been identified and characterized in multiple nontyphoidal Salmonella (NTS) serotypes as well. The significance of S-CDT in salmonellosis with regards to the: (i) distribution of S-CDT encoding genes among NTS serotypes, (ii) contributions to pathogenicity, (iii) regulation of S-CDT expression, and (iv) the public health implication of S-CDT as it relates to disease severity, are reviewed here.
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Affiliation(s)
- Rachel Miller
- Department of Food Science, Cornell University, Ithaca, NY 14850 USA.
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, NY 14850 USA.
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Shams S, Bakhshi B, Tohidi Moghadam T. In Silico Analysis of the cadF Gene and Development of a Duplex Polymerase Chain Reaction for Species-Specific Identification of Campylobacter jejuni and Campylobacter coli. Jundishapur J Microbiol 2016; 9:e29645. [PMID: 27127589 PMCID: PMC4842252 DOI: 10.5812/jjm.29645] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 09/28/2015] [Accepted: 11/03/2015] [Indexed: 11/16/2022] Open
Abstract
Background Campylobacteriosis is a zoonotic infectious disease caused by Campylobacter jejuni and C. coli. The cadF gene is considered as a genus-specific gene while other genes are mainly used for discrimination at the species level. Objectives This study aimed to analyze the cadF gene and to develop a duplex PCR assay for simultaneous detection of C. coli and C. jejuni, the two commonly encountered species. Materials and Methods In silico analysis of the cadF gene was carried out by several software and available online tools. A duplex PCR optimized with specific primers was used for detection and differentiation of both species. To evaluate specificity and sensitivity of the test, a panel of different Campylobacter spp. together with several intestinal bacterial pathogens was tested. The limit of detection (LOD) of method was determined using serial dilutions of standard genomes. Results The analysis of the full size cadF gene indicated variations in this gene, which can be used to differentiate C. jejuni and C. coli. The duplex PCR designed in this study showed that it could simultaneously detect and differentiate both C. jejuni and C. coli with product sizes of 737 bp and 461 bp, respectively. This assay, with 100% specificity and sensitivity, had a limit of detection (LOD) of about 14 and 0.7 µg/mL for C. jejuni and C. coli, respectively. Conclusions In silico analysis of the cadF full-gene showed variations between the two species that can be used as a molecular target for differentiating C. jejuni and C. coli in a single-step duplex-PCR assay with high specificity and sensitivity.
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Affiliation(s)
- Saeed Shams
- Department of Medical Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, IR Iran
| | - Bita Bakhshi
- Department of Medical Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, IR Iran
- Corresponding author: Bita Bakhshi, Department of Medical Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, IR Iran. Tel: +98-2182884558, Fax: +98-2182884555, E-mail:
| | - Tahereh Tohidi Moghadam
- Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, IR Iran
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Campylobacter hyointestinalis Isolated from Pigs Produces Multiple Variants of Biologically Active Cytolethal Distending Toxin. Infect Immun 2015; 83:4304-13. [PMID: 26283337 DOI: 10.1128/iai.00997-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 08/11/2015] [Indexed: 11/20/2022] Open
Abstract
Campylobacter hyointestinalis isolated from swine with proliferative enteritis often is considered to be pathogenic. While the precise virulence mechanisms of this species remain unclear, we have recently identified a cytolethal distending toxin (cdt) gene cluster in C. hyointestinalis isolated from a patient with diarrhea (W. Samosornsuk et al., J Med Microbiol, 27 July 2015, http://dx.doi.org/10.1099/jmm.0.000145). However, the sequences of the cdt genes in C. hyointestinalis were found to be significantly different and the gene products are immunologically distinct from those of other Campylobacter species. In this study, we demonstrate the presence of a second variant of the cdt gene cluster in C. hyointestinalis, designated cdt-II, while the former is named cdt-I. Sequencing of the cdt-II gene cluster and deduced amino acid sequences revealed that homologies between the subunits CdtA, CdtB, and CdtC of ChCDT-I and ChCDT-II are 25.0, 56.0, and 24.8%, respectively. Furthermore, the CdtB subunit of ChCDT-II was found to be immunologically unrelated to that of ChCDT-I by Ouchterlony double gel diffusion test. Recombinant ChCDT-II also induced cell distention and death of HeLa cells by blocking the cell cycle at G2/M phase. Interestingly, the cdt-II genes were detected in all 23 animal isolates and in 1 human isolate of C. hyointestinalis, and 21 of these strains carried both cdt-I and cdt-II gene clusters. Altogether, our results indicate that ChCDT-II is an important virulence factor of C. hyointestinalis in animals.
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Kamei K, Kawabata H, Asakura M, Samosornsuk W, Hinenoya A, Nakagawa S, Yamasaki S. A Cytolethal Distending Toxin Gene-Based Multiplex PCR Assay for Campylobacter jejuni, C. fetus, C. coli, C. upsaliensis, C. hyointestinalis, and C. lari. Jpn J Infect Dis 2015; 69:256-8. [PMID: 26255737 DOI: 10.7883/yoken.jjid.2015.182] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In this study, we devised a multiplex PCR assay based on the gene of cytolethal distending toxin (cdt) B subunit to simultaneously detect and discriminate Campylobacter jejuni, C. fetus, C. coli, C. upsaliensis, C. hyointestinalis, and C. lari. Species-specific PCR products were successfully obtained from all 38 C. jejuni, 12 C. fetus, 39 C. coli, 22 C. upsaliensis, 24 C. hyointestinalis, and 7 C. lari strains tested. On the other hand, no specific PCR products were obtained from other campylobacters and bacterial species tested (41 strains in total). The proposed multiplex PCR assay is a valuable tool for detection and descrimination of 6 major Campylobacter species, that are associated with gastrointestinal diseases in humans.
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Affiliation(s)
- Kazumasa Kamei
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
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