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Chumbler NM, Rutherford SA, Zhang Z, Farrow MA, Lisher JP, Farquhar E, Giedroc DP, Spiller BW, Melnyk RA, Lacy DB. Crystal structure of Clostridium difficile toxin A. Nat Microbiol 2016; 1:15002. [PMID: 27571750 PMCID: PMC4976693 DOI: 10.1038/nmicrobiol.2015.2] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/18/2015] [Indexed: 02/04/2023]
Abstract
Clostridium difficile infection is the leading cause of hospital-acquired diarrhoea and pseudomembranous colitis. Disease is mediated by the actions of two toxins, TcdA and TcdB, which cause the diarrhoea, as well as inflammation and necrosis within the colon. The toxins are large (308 and 270 kDa, respectively), homologous (47% amino acid identity) glucosyltransferases that target small GTPases within the host. The multidomain toxins enter cells by receptor-mediated endocytosis and, upon exposure to the low pH of the endosome, insert into and deliver two enzymatic domains across the membrane. Eukaryotic inositol-hexakisphosphate (InsP6) binds an autoprocessing domain to activate a proteolysis event that releases the N-terminal glucosyltransferase domain into the cytosol. Here, we report the crystal structure of a 1,832-amino-acid fragment of TcdA (TcdA1832), which reveals a requirement for zinc in the mechanism of toxin autoprocessing and an extended delivery domain that serves as a scaffold for the hydrophobic α-helices involved in pH-dependent pore formation. A surface loop of the delivery domain whose sequence is strictly conserved among all large clostridial toxins is shown to be functionally important, and is highlighted for future efforts in the development of vaccines and novel therapeutics.
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Affiliation(s)
- Nicole M. Chumbler
- Chemical and Physical Biology Program, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Stacey A. Rutherford
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Zhifen Zhang
- Department of Biochemistry, University of Toronto and the Molecular Structure & Function Research Institute at The Hospital for Sick Children, Toronto, Ontario M5S 1A8, Canada
| | - Melissa A. Farrow
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - John P. Lisher
- Interdisciplinary Graduate Program in Biochemistry, Indiana University, Bloomington, Indiana 47405, USA
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - Erik Farquhar
- Case Western Reserve University Center for Synchrotron Biosciences, National Synchrotron Light Source, Building 725, Brookhaven National Laboratory, New York 11973, USA
| | - David P. Giedroc
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - Benjamin W. Spiller
- Chemical and Physical Biology Program, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37212, USA
| | - Roman A. Melnyk
- Department of Biochemistry, University of Toronto and the Molecular Structure & Function Research Institute at The Hospital for Sick Children, Toronto, Ontario M5S 1A8, Canada
| | - D. Borden Lacy
- Chemical and Physical Biology Program, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37205, USA
- The Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee 37212, USA
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DuVall JA, Cabaniss ST, Angotti ML, Moore JH, Abhyankar M, Shukla N, Mills DL, Kessel BG, Garner GT, Swami NS, Landers JP. Rapid detection of Clostridium difficile via magnetic bead aggregation in cost-effective polyester microdevices with cell phone image analysis. Analyst 2016; 141:5637-45. [DOI: 10.1039/c6an00674d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A centrifugally-driven polyester microdevice for sequence-specific detection ofClostridium difficileusing magnetic beads, isothermal amplification, and cell phone image analysis.
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Affiliation(s)
| | | | | | - John H. Moore
- Department of Electrical and Computer Engineering
- University of Virginia
- Charlottesville
- USA
| | - Mayuresh Abhyankar
- Department of Medicine
- Infectious Diseases and International Health
- University of Virginia
- Charlottesville
- USA
| | - Nishant Shukla
- Department of Electrical and Computer Engineering
- University of Virginia
- Charlottesville
- USA
| | | | - Bryan G. Kessel
- Department of Mechanical and Aerospace Engineering
- University of Virginia
- Charlottesville
- USA
| | - Gavin T. Garner
- Department of Mechanical and Aerospace Engineering
- University of Virginia
- Charlottesville
- USA
| | - Nathan S. Swami
- Department of Electrical and Computer Engineering
- University of Virginia
- Charlottesville
- USA
| | - James P. Landers
- Department of Chemistry
- University of Virginia
- Charlottesville
- USA
- TeGrex Technologies
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53
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Molecular Diagnosis of Gastrointestinal Infections. Mol Microbiol 2016. [DOI: 10.1128/9781555819071.ch27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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54
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Ultrasensitive Detection and Quantification of Toxins for Optimized Diagnosis of Clostridium difficile Infection. J Clin Microbiol 2015; 54:259-64. [PMID: 26659205 DOI: 10.1128/jcm.02419-15] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Recently developed ultrasensitive and quantitative methods for detection of Clostridium difficile toxins provide new tools for diagnosis and, potentially, for management of C. difficile infection (CDI). Compared to methods that detect toxigenic organism, ultrasensitive toxin detection may allow diagnosis of CDI with increased clinical specificity, without sacrificing clinical sensitivity; measurement of toxin levels may also provide information relevant to disease prognosis. This minireview provides an overview of these new toxin detection technologies and considers what these new tools might add to the field.
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Angione SL, Croote D, Leung JW, Mermel LA, Tripathi A. Single fluorophore melting curve analysis for detection of hypervirulent Clostridium difficile. J Med Microbiol 2015; 65:62-70. [PMID: 26516039 DOI: 10.1099/jmm.0.000199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This study demonstrates a novel detection assay able to identify and subtype strains of Clostridium difficile. Primers carefully designed for melting curve analysis amplify DNA from three C. difficile genes, tcdB, tcdC and cdtB, during quantitative (q)PCR. The tcdB gene allows for confirmation of organism presence, whilst the tcdC and cdtB genes allow for differentiation of virulence status, as deletions in the tcdC gene and the concurrent presence of the cdtB gene, which produces binary toxin, are associated with hypervirulence. Following qPCR, subtyping is then achieved by automated, inline melting curve analysis using only a single intercalating dye and verified by microchip electrophoresis. This assay represents a novel means of distinguishing between toxigenic and hypervirulent C. difficile strains NAP1/027/BI and 078 ribotype, which are highly prevalent hypervirulent strains in humans. This methodology can help rapidly detect and identify C. difficile strains that impose a significant health and economic burden in hospitals and other healthcare settings.
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Affiliation(s)
- Stephanie L Angione
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA
| | - Derek Croote
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA
| | - Joshua W Leung
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA
| | - Leonard A Mermel
- Division of Infectious Diseases, Department of Medicine, Rhode Island Hospital, , Providence, RI, USA.,Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Anubhav Tripathi
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA
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56
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Chen W, Liu WE, Li YM, Luo S, Zhong YM. Preparation and preliminary application of monoclonal antibodies to the receptor binding region of Clostridium difficile toxin B. Mol Med Rep 2015; 12:7712-20. [PMID: 26459027 DOI: 10.3892/mmr.2015.4369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 07/21/2015] [Indexed: 11/05/2022] Open
Abstract
A previous nationwide Chinese epidemiological study revealed through isolation of A‑B+ Clostridium difficile strains, which produce toxin B (TcdB), but not toxin A TcdA, that the strains are widespread and more frequent in east Asian countries,. The development of a process capable of detecting TcdB is required in microbiological laboratories in order to facilitate the control of the A‑B+ C. difficile strains, however, no diagnostic reagents have been developed to date. The aim of the present study was to prepare monoclonal antibodies (mAbs) targeting the receptor binding region of TcdB (CDB3), and to establish a double‑antibody sandwich enzyme-linked immunosorbent assay (ds‑ELISA), which can be used for the diagnosis of C. difficile infection. The recombinant protein, glutathione S transferase (GST)‑CDB3 was expressed and purified using an Escherichia coli system. BALB/c mice were immunized with GST‑CDB3 recombinant protein. A hybridoma technique was used for the production of anti‑CDB3 mAb. The hybridoma clones were then screened using indirect ELISA, and anti‑CDB3 mAb was produced in the ascites of the BALB/c mice. Isotyping of anti‑CDB3 mAb was performed using an SBA Clonotyping system/horseradish peroxidase (HRP) ELISA kit. Protein G affinity chromatography was used for purification of anti‑CDB3 mAbs, and the titer and specificity of the anti‑CDB3 mAbs were assessed using indirect ELISA and western blot analysis, respectively. The ds‑ELISA was established using HRP‑labeled anti‑CDB3 mAbd, which were used to detect TcdB clinically in diarrhea stools. A total of five stable hybridoma cell clones (1E7B, 1F8D3, 2F8A6, 3B6F1 and 4A4G2) producing anti‑CDB3 mAb were established. The results of the present study indicated that the immunoglobulin (Ig)G isotype was predominant, as 1E7B2 IgG1 (λ), 2F8A6 IgG2a (κ) and 4A4G2 IgG1 (κ). In addition, the highest titer of anti‑CDB3 mAb (2F8A6 and 4A4G2) was 1:51,200. Western blotting revealed that the 2F8A6 and 4A4G2 mAbs recognized the CDB3 protein specifically. Following anti‑CDB3 mAb (4A4G2) HRP‑labeling, the optimal working concentration was confirmed to be 1:400, and the concentration of coated antibody (2F8A6) was 20 µg/ml. The sensitivity of the ds‑ELISA was 73.33% for the A+B+ toxigenic C. difficile strains, and 86.67% for the A‑B+ toxigenic C. difficile strains, with a specificity of 100% for all. In conclusion, the present study successfully developed novel mAbs specific to CDB3, and developed a ds-ELISA kit with high specificity and sensitivity for the rapid detection of TcdB. This offers a useful tool for the diagnostic assessment of TcdB.
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Affiliation(s)
- Wei Chen
- Department of Clinical Laboratory, Xiangya Hospital of Central South University, Changsha, Hunan 410008, P.R. China
| | - Wen-En Liu
- Department of Clinical Laboratory, Xiangya Hospital of Central South University, Changsha, Hunan 410008, P.R. China
| | - Yan-Ming Li
- Department of Clinical Laboratory, Xiangya Hospital of Central South University, Changsha, Hunan 410008, P.R. China
| | - Shan Luo
- Department of Clinical Laboratory, Xiangya Hospital of Central South University, Changsha, Hunan 410008, P.R. China
| | - Yi-Ming Zhong
- Department of Clinical Laboratory, Xiangya Hospital of Central South University, Changsha, Hunan 410008, P.R. China
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Czepiel J, Kozicki M, Panasiuk P, Birczyńska M, Garlicki A, Wesełucha-Birczyńska A. Clostridium difficile the hospital plague. Analyst 2015; 140:2513-22. [PMID: 25627751 DOI: 10.1039/c4an01947d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Clostridium difficile infection (CDI) has become one of the major public health threats in the last two decades. An increase has been observed not only in the rate of CDI, but also in its severity and mortality. Symptoms caused by this pathogen are accompanied by intense local and systemic inflammation. We confirmed that Raman microspectroscopy can help us in understanding CDI pathogenesis. A single erythrocyte of patients with CDI shows a difference, approximately 10 times, in the intensity of the Raman spectra at the beginning of hospitalization and after one week of treatment. The intensity level is an indicator of the spread of the inflammation within the cell, confirmed by standard laboratory tests. Many of the observed bands with enormously enhanced intensity, e.g. 1587, 1344, 1253, 1118 and 664 cm(-1), come from the symmetric vibration of the pyrrole ring. Heme variation of recovered cells in the acute CDI state between the first and the seventh day of treatment seems to show increased levels of oxygenated hemoglobin. Intense inflammation alters the conformation of the protein which is reflected in the significant changes in the amide I, II and III bands. There is an observed shift and a significant intensity increase of 1253 and 970 cm(-1) amide III and skeletal protein backbone CC stretching vibration bands, respectively. Principal Component Analysis (PCA) was used to find the variance in the data collected on the first and seventh day. PC2 loading in the 1645-1500 cm(-1) range shows an increase of heme, Tyr, Trp, or Phe vibrations because of changes in the protein microenvironment due to their exposure. Positive maxima at 1621, 1563 and 1550 in the PC2 loading originated from the ring vibrations. These observations indicate that Clostridium difficile toxins induce cytopathogenicity by altering cellular proteins.
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Affiliation(s)
- J Czepiel
- Department of Infectious Diseases, Jagiellonian University, Medical College, Sniadeckich 5, Kraków, Poland.
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58
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Biochemical and Immunological Characterization of Truncated Fragments of the Receptor-Binding Domains of C. difficile Toxin A. PLoS One 2015; 10:e0135045. [PMID: 26271033 PMCID: PMC4536038 DOI: 10.1371/journal.pone.0135045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 07/17/2015] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile is an emerging pathogen responsible for opportunistic infections in hospitals worldwide and is the main cause of antibiotic-associated pseudo-membranous colitis and diarrhea in humans. Clostridial toxins A and B (TcdA and TcdB) specifically bind to unknown glycoprotein(s) on the surface of epithelial cells in the host intestine, disrupting the intestinal barrier and ultimately leading to acute inflammation and diarrhea. The C-terminal receptor-binding domain (RBD) of TcdA, which is responsible for the initial binding of the toxin to host glycoproteins, has been predicted to contain 7 potential oligosaccharide-binding sites. To study the specific roles and functions of these 7 putative lectin-like binding regions, a consensus sequence of TcdA RBD derived from different C. difficile strains deposited in the NCBI protein database and three truncated fragments corresponding to the N-terminal (residues 1–411), middle (residues 296–701), and C-terminal portions (residues 524–911) of the RBD (F1, F2 and F3, respectively) were designed and expressed in Escherichia coli. In this study, the recombinant RBD (rRBD) and its truncated fragments were purified, characterized biologically and found to have the following similar properties: (a) are capable of binding to the cell surface of both Vero and Caco-2 cells; (b) possess Toll-like receptor agonist-like adjuvant activities that can activate dendritic cell maturation and increase the secretion of pro-inflammatory cytokines; and (c) function as potent adjuvants in the intramuscular immunization route to enhance immune responses against weak immunogens. Although F1, F2 and F3 have similar repetitive amino acid sequences and putative oligosaccharide-binding domains, they do not possess the same biological and immunological properties: (i) TcdA rRBD and its fragments bind to the cell surface, but only TcdA rRBD and F3 internalize into Vero cells within 15 min; (ii) the fragments exhibit various levels of hemagglutinin (HA) activity, with the exception of the F1 fragment, which demonstrates no HA activity; and (iii) in the presence of alum, all fragments elicit various levels of anti-toxin A-neutralizing antibody responses, but those neutralizing antibodies elicited by F2 did not protect mice against a TcdA challenge. Because TcdA rRBD, F1 and F3 formulated with alum can elicit immune protective responses against the cytotoxicity of TcdA, they represent potential components of future candidate vaccines against C. difficile-associated diseases.
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Huang JH, Wu CW, Lien SP, Leng CH, Hsiao KN, Liu SJ, Chen HW, Siu LK, Chong P. Recombinant lipoprotein-based vaccine candidates against C. difficile infections. J Biomed Sci 2015; 22:65. [PMID: 26245825 PMCID: PMC4527207 DOI: 10.1186/s12929-015-0171-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 07/29/2015] [Indexed: 12/18/2022] Open
Abstract
Background Opportunistically nosocomial infections in hospitalized patients are often related to Clostridium difficile infections (CDI) due to disruption of the intestinal micro-flora by antibiotic therapies during hospitalization. Clostridial exotoxins A and B (TcdA and TcdB) specifically bind to unknown glycoprotein(s) in the host intestine, disrupt the intestinal barrier leading to acute inflammation and diarrhea. The C-terminal receptor binding domain of TcdA (A-rRBD) has been shown to elicit antibody responses that neutralize TcdA toxicity in Vero cell cytotoxicity assays, but not effectively protect hamsters against a lethal dose challenge of C. difficile spores. To develop an effective recombinant subunit vaccine against CDI, A-rRBD was lipidated (rlipoA-RBD) as a rational design to contain an intrinsic adjuvant, a toll-like receptor 2 agonist and expressed in Escherichia coli. Results The purified rlipoA-RBD was characterized immunologically and found to have the following properties: (a) mice, hamsters and rabbits vaccinated with 3 μg of rlipoA-RBD produced strong antibody responses that neutralized TcdA toxicity in Vero cell cytotoxicity assays; furthermore, the neutralization titer was comparable to those obtained from antisera immunized either with 10 μg of TcdA toxoid or 30 μg of A-rRBD; (b) rlipoA-RBD elicited immune responses and protected mice from TcdA challenge, but offered insignificant protection (10 to 20 %) against C. difficile spores challenge in hamster models; (c) only rlipoA-RBD formulated with B-rRBD consistently confers protection (90 to 100 %) in the hamster challenge model; and (d) rlipoA-RBD was found to be 10-fold more potent than A-rRBD as an adjuvant to enhancing immune responses against a poor antigen such as ovalbumin. Conclusion These results indicate that rlipoA-RBD formulated with B-rRBD could be an excellent vaccine candidate for preclinical studies and future clinical trials.
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Affiliation(s)
- Jui-Hsin Huang
- Vaccine R&D Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan. .,Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan.
| | - Chia-Wei Wu
- Vaccine R&D Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan.
| | - Shu-Pei Lien
- Vaccine R&D Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan.
| | - Chih-Hsiang Leng
- Vaccine R&D Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan.
| | - Kuang-Nan Hsiao
- Vaccine R&D Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan.
| | - Shih-Jen Liu
- Vaccine R&D Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan.
| | - Hsin-Wei Chen
- Vaccine R&D Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan.
| | - Leung-Kei Siu
- Vaccine R&D Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan.
| | - Pele Chong
- Vaccine R&D Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan. .,Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan. .,Graduate Institute of Immunology, China Medical University, Taichung, Taiwan.
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Verhoye E, Vandecandelaere P, De Beenhouwer H, Coppens G, Cartuyvels R, Van den Abeele A, Frans J, Laffut W. A hospital-level cost-effectiveness analysis model for toxigenic Clostridium difficile detection algorithms. J Hosp Infect 2015; 91:123-8. [PMID: 26231269 DOI: 10.1016/j.jhin.2015.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 02/13/2015] [Indexed: 12/24/2022]
Abstract
BACKGROUND Despite thorough analyses of the analytical performance of Clostridium difficile tests and test algorithms, the financial impact at hospital level has not been well described. Such a model should take institution-specific variables into account, such as incidence, request behaviour and infection control policies. AIM To calculate the total hospital costs of different test algorithms, accounting for days on which infected patients with toxigenic strains were not isolated and therefore posed an infectious risk for new/secondary nosocomial infections. METHODS A mathematical algorithm was developed to gather the above parameters using data from seven Flemish hospital laboratories (Bilulu Microbiology Study Group) (number of tests, local prevalence and hospital hygiene measures). Measures of sensitivity and specificity for the evaluated tests were taken from the literature. List prices and costs of assays were provided by the manufacturer or the institutions. The calculated cost included reagent costs, personnel costs and the financial burden following due and undue isolations and antibiotic therapies. Five different test algorithms were compared. FINDINGS AND CONCLUSION A dynamic calculation model was constructed to evaluate the cost:benefit ratio of each algorithm for a set of institution- and time-dependent inputted variables (prevalence, cost fluctuations and test performances), making it possible to choose the most advantageous algorithm for its setting. A two-step test algorithm with concomitant glutamate dehydrogenase and toxin testing, followed by a rapid molecular assay was found to be the most cost-effective algorithm. This enabled resolution of almost all cases on the day of arrival, minimizing the number of unnecessary or missing isolations.
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Affiliation(s)
- E Verhoye
- Laboratory of Microbiology, Onze-Lieve-Vrouw Hospital, Aalst, Belgium.
| | | | - H De Beenhouwer
- Laboratory of Microbiology, Onze-Lieve-Vrouw Hospital, Aalst, Belgium
| | - G Coppens
- Clinical Laboratory, Hospital Oost-Limburg, Genk, Belgium
| | - R Cartuyvels
- Clinical Laboratory, Jessa Hospital, Hasselt, Belgium
| | - A Van den Abeele
- Laboratory of Microbiology, General Hospital Sint-Lucas, Gent, Belgium
| | - J Frans
- Clinical Laboratory, Imelda Hospital, Bonheiden, Belgium
| | - W Laffut
- Clinical Laboratory, Heilig Hart Hospital, Lier, Belgium
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Yimer M, Gezhagne M, Biruk T, Dinaol B. A review on major bacterial causes of calf diarrhea and its diagnostic method. ACTA ACUST UNITED AC 2015. [DOI: 10.5897/jvmah2014.0351] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Abstract
The best laboratory diagnostic approach to detect Clostridium difficile infection (CDI) is the subject of ongoing debate. In the United States, nucleic acid amplification tests (NAAT) have become the most widely used tests for making this diagnosis. Detection of toxin in stool may be a better predictor of CDI disease and severity. Laboratories that have switched from toxin-based to NAAT-based methods have significantly higher CDI detection rates. The important issue is whether all NAAT-positive patients have CDI or at least some of those patients are excretors of the organism and do not have clinical disease.
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Affiliation(s)
- Peter H Gilligan
- Clinical Microbiology-Immunology Laboratories, Microbiology-Immunology, UNC Health Care, UNC School of Medicine, CB 7600, Chapel Hill, NC 27516, USA; Pathology-Laboratory Medicine, UNC School of Medicine, CB 7600, Chapel Hill, NC 27516, USA.
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63
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Polyclonal Antibody Therapies for Clostridium difficile Infection. Antibodies (Basel) 2014. [DOI: 10.3390/antib3040272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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64
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Gilligan PH. Contemporary approaches for the laboratory diagnosis of Clostridium difficile infections. SEMINARS IN COLON AND RECTAL SURGERY 2014. [DOI: 10.1053/j.scrs.2014.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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65
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An optimized, synthetic DNA vaccine encoding the toxin A and toxin B receptor binding domains of Clostridium difficile induces protective antibody responses in vivo. Infect Immun 2014; 82:4080-91. [PMID: 25024365 DOI: 10.1128/iai.01950-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile-associated disease (CDAD) constitutes a large majority of nosocomial diarrhea cases in industrialized nations and is mediated by the effects of two secreted toxins, toxin A (TcdA) and toxin B (TcdB). Patients who develop strong antitoxin antibody responses can clear C. difficile infection and remain disease free. Key toxin-neutralizing epitopes have been found within the carboxy-terminal receptor binding domains (RBDs) of TcdA and TcdB, which has generated interest in developing the RBD as a viable vaccine target. While numerous platforms have been studied, very little data describes the potential of DNA vaccination against CDAD. Therefore, we created highly optimized plasmids encoding the RBDs from TcdA and TcdB in which any putative N-linked glycosylation sites were altered. Mice and nonhuman primates were immunized intramuscularly, followed by in vivo electroporation, and in these animal models, vaccination induced significant levels of both anti-RBD antibodies (blood and stool) and RBD-specific antibody-secreting cells. Further characterization revealed that sera from immunized mice and nonhuman primates could detect RBD protein from transfected cells, as well as neutralize purified toxins in an in vitro cytotoxicity assay. Mice that were immunized with plasmids or given nonhuman-primate sera were protected from a lethal challenge with purified TcdA and/or TcdB. Moreover, immunized mice were significantly protected when challenged with C. difficile spores from homologous (VPI 10463) and heterologous, epidemic (UK1) strains. These data demonstrate the robust immunogenicity and efficacy of a TcdA/B RBD-based DNA vaccine in preclinical models of acute toxin-associated and intragastric, spore-induced colonic disease.
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Lee JH, Lee Y, Lee K, Riley TV, Kim H. The changes of PCR ribotype and antimicrobial resistance of Clostridium difficile in a tertiary care hospital over 10 years. J Med Microbiol 2014; 63:819-823. [DOI: 10.1099/jmm.0.072082-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The aims of this study were to investigate any change in PCR ribotypes and to determine the antimicrobial resistance of common PCR ribotypes over a 10-year period in a tertiary care hospital. We conducted PCR ribotyping, antimicrobial susceptibility testing and DNA gyrase sequencing to identify changes in 1407 Clostridium difficile non-duplicated isolates obtained between 2000 and 2009. A total of 74 different ribotypes were found. The most prevalent ribotype was ribotype 001 (26.1 %). The prevalence of ribotype 017 was 17 % and that of ribotype 014/020 was 9.6 %. Ribotyping showed that the prevalence of ribotype 001 decreased and the prevalence of ribotypes 017, 014/020 and 018 increased over the 10 years. Antimicrobial resistance rates in prevalent ribotypes were: clindamycin, 81 %; cefotetan, 19 %; moxifloxacin, 42 %; imipenem, 8 %; ciprofloxacin, 100 % and erythromycin, 80 %. Ribotype 018 showed greater antimicrobial resistance than other ribotypes. All ribotype 018 strains showing moxifloxacin resistance had a substitution of a gyrA coding amino acid (Thr82 to Ile). This study will help the understanding of PCR ribotype trends and antimicrobial resistance of C. difficile in Korea.
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Affiliation(s)
- Jong-Han Lee
- Department of Laboratory Medicine, Korea University College of Medicine, Seoul, Korea
| | - Yangsoon Lee
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea
| | - Kyungwon Lee
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea
| | - Thomas V. Riley
- Microbiology and Immunology, University of Western Australia, Perth, Western Australia
| | - Heejung Kim
- Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea
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68
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Asymptomatic Carriers and Captive Audiences. Food Saf (Tokyo) 2014. [DOI: 10.1128/9781555816186.ch12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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69
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A Microbial Who's Who. Food Saf (Tokyo) 2014. [DOI: 10.1128/9781555816186.app1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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70
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Diagnosis of Clostridium difficile infection: an ongoing conundrum for clinicians and for clinical laboratories. Clin Microbiol Rev 2014; 26:604-30. [PMID: 23824374 DOI: 10.1128/cmr.00016-13] [Citation(s) in RCA: 294] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Clostridium difficile is a formidable nosocomial and community-acquired pathogen, causing clinical presentations ranging from asymptomatic colonization to self-limiting diarrhea to toxic megacolon and fulminant colitis. Since the early 2000s, the incidence of C. difficile disease has increased dramatically, and this is thought to be due to the emergence of new strain types. For many years, the mainstay of C. difficile disease diagnosis was enzyme immunoassays for detection of the C. difficile toxin(s), although it is now generally accepted that these assays lack sensitivity. A number of molecular assays are commercially available for the detection of C. difficile. This review covers the history and biology of C. difficile and provides an in-depth discussion of the laboratory methods used for the diagnosis of C. difficile infection (CDI). In addition, strain typing methods for C. difficile and the evolving epidemiology of colonization and infection with this organism are discussed. Finally, considerations for diagnosing C. difficile disease in special patient populations, such as children, oncology patients, transplant patients, and patients with inflammatory bowel disease, are described. As detection of C. difficile in clinical specimens does not always equate with disease, the diagnosis of C. difficile infection continues to be a challenge for both laboratories and clinicians.
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71
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Tsutsumi LS, Owusu YB, Hurdle JG, Sun D. Progress in the discovery of treatments for C. difficile infection: A clinical and medicinal chemistry review. Curr Top Med Chem 2014; 14:152-75. [PMID: 24236721 PMCID: PMC3921470 DOI: 10.2174/1568026613666131113154753] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/06/2013] [Accepted: 09/15/2013] [Indexed: 02/07/2023]
Abstract
Clostridium difficile is an anaerobic, Gram-positive pathogen that causes C. difficile infection, which results in significant morbidity and mortality. The incidence of C. difficile infection in developed countries has become increasingly high due to the emergence of newer epidemic strains, a growing elderly population, extensive use of broad spectrum antibiotics, and limited therapies for this diarrheal disease. Because treatment options currently available for C. difficile infection have some drawbacks, including cost, promotion of resistance, and selectivity problems, new agents are urgently needed to address these challenges. This review article focuses on two parts: the first part summarizes current clinical treatment strategies and agents under clinical development for C. difficile infection; the second part reviews newly reported anti-difficile agents that have been evaluated or reevaluated in the last five years and are in the early stages of drug discovery and development. Antibiotics are divided into natural product inspired and synthetic small molecule compounds that may have the potential to be more efficacious than currently approved treatments. This includes potency, selectivity, reduced cytotoxicity, and novel modes of action to prevent resistance.
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Affiliation(s)
| | | | | | - Dianqing Sun
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawai'i at Hilo, 34 Rainbow Drive, Hilo, HI 96720, USA.
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72
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Denys GA. Portrait Toxigenic Clostridium difficile assay, an isothermal amplification assay detects toxigenic C. difficile in clinical stool specimens. Expert Rev Mol Diagn 2013; 14:17-26. [PMID: 24308336 DOI: 10.1586/14737159.2014.864239] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The Portrait Toxigenic Clostridium difficile assay is a rapid, qualitative assay for the detection of the tcdB gene of C. difficile in stool specimens from patients suspected of C. difficile infections, and received 510(k) clearance by the US FDA in March 2012. The Portrait Toxigenic C. difficile assay combines novel blocked-primer-mediated helicase-dependent multiplex amplification (bpHDA) technology and chip-based detection in an automated sample-to-result format. The assay requires minimal sample preparation and results are available within 90 min. In a multicenter evaluation, the Portrait Toxigenic C. difficile assay had a sensitivity of 98.2% and specificity of 92.8% compared with toxigenic culture. A comparative study between the Portrait Toxigenic C. difficile assay and three FDA-cleared molecular assays for the detection of toxigenic C. difficile exhibited a high degree of agreement (93.8-97.5%). The Portrait Toxigenic C. difficile assay provides a simple, cost-effective method with broad applicability to panel-based approaches, potentially simplifying workflow.
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Affiliation(s)
- Gerald A Denys
- Department of Pathology and Laboratory Medicine, Division of Clinical Microbiology, Indiana University School of Medicine, 350 West 11th Street, Room 6027B, Indianapolis, IN, USA
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73
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Monteiro AA, Pires RN, Baethgen LF, Carneiro LC, Tavares RG, Caierão J, Park S, Perlin DS, Rodrigues Filho EM, Pasqualotto AC. Discrepancies among three laboratory methods for Clostridium difficile detection and a proposal for their optimal use. FEMS Microbiol Lett 2013; 350:133-7. [PMID: 24236508 DOI: 10.1111/1574-6968.12330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 11/07/2013] [Indexed: 11/30/2022] Open
Abstract
Clostridium difficile is the major cause of nosocomial diarrhoea. Several detection methods are available for the laboratory diagnosis of C. difficile, but these vary in terms of sensitivity and specificity. In this study, we compared the performance of three following laboratory tests to detect C. difficile: in-house real-time PCR aiming for toxin B gene (tcdB), EIA for detection of toxins A and B (Premier Toxins A & B) and C. difficile culture in selective medium (bioMerieux). Our results were grouped into three categories as follows: (1) C. difficile-associated diarrhoea (CDAD); (2) asymptomatic carriers; and (3) negative results. Among the 113 patients included in the study, 9 (8.0%) were classified as CDAD, 19 (16.8%) were asymptomatic carriers, 76 (67.2%) had negative results and 9 (8.0%) could not be categorized (positive test for C. difficile toxins only). PCR was found to be the most sensitive diagnostic test in our study, with the potential to be used as a screening method for C. difficile colonization/CDAD. Diagnosis of CDAD would be better performed by a combination of PCR and EIA tests.
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74
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Scaria J, Mao C, Chen JW, McDonough SP, Sobral B, Chang YF. Differential stress transcriptome landscape of historic and recently emerged hypervirulent strains of Clostridium difficile strains determined using RNA-seq. PLoS One 2013; 8:e78489. [PMID: 24244315 PMCID: PMC3820578 DOI: 10.1371/journal.pone.0078489] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 09/12/2013] [Indexed: 12/18/2022] Open
Abstract
C. difficile is the most common cause of nosocomial diarrhea in North America and Europe. Genomes of individual strains of C. difficile are highly divergent. To determine how divergent strains respond to environmental changes, the transcriptomes of two historic and two recently isolated hypervirulent strains were analyzed following nutrient shift and osmotic shock. Illumina based RNA-seq was used to sequence these transcriptomes. Our results reveal that although C. difficile strains contain a large number of shared and strain specific genes, the majority of the differentially expressed genes were core genes. We also detected a number of transcriptionally active regions that were not part of the primary genome annotation. Some of these are likely to be small regulatory RNAs.
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Affiliation(s)
- Joy Scaria
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, United States of America
| | - Chunhong Mao
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Jenn-Wei Chen
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, United States of America
| | - Sean P. McDonough
- Department of Biomedical Sciences, Cornell University, Ithaca, New York, United States of America;
| | - Bruno Sobral
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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75
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Fang YS, Chen SY, Huang XJ, Wang LS, Wang HY, Wang JF. Simple approach for ultrasensitive electrochemical immunoassay of Clostridium difficile toxin B detection. Biosens Bioelectron 2013; 53:238-44. [PMID: 24141113 DOI: 10.1016/j.bios.2013.09.063] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/17/2013] [Accepted: 09/26/2013] [Indexed: 01/05/2023]
Abstract
Clostridium difficile toxin B (Tcd B), as one of the primary contributing factors to the pathogenesis of C. difficile-associated diseases, has raised serious public concerns due to its virulence, spore-forming ability and persistence with major types of infectious diarrhea diseases, and been used as a potential biomarker in clinical diagnoses. Thus, a simple method for the determination of Tcd B was developed based on a sandwich-type electrochemical immunosensor. Greatly enhanced sensitivity was achieved based on fabricating the immunosensor by layer-by-layer coating carbon nanotubes (MWCNTs), Prussian blue (PB), Chitosan (CS), Glutaraldehyde (GA) composite on the working electrode as well as using graphene oxide (GO) as a nanocarrier in a multienzyme amplification strategy. In comparison with conventional methods, the proposed immunoassay exhibited high sensitivity and selectivity for the detection of Tcd B, providing a better linear response range from 0.003 to 320 ng/mL and a lower limit of detection (LOD) of 0.7 pg/mL (S/N=3) under optimal experimental conditions. The immunosensor exhibited convenience, low cost, rapidity, good specificity, acceptable stability and reproducibility. Moreover, satisfactory results were obtained for the determination of Tcd B in real human stool samples, indicating that the developed immunoassay has the potential to find application in clinical detection of Tcd B and other tumor markers as an alternative approach.
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Affiliation(s)
- Yi-Shan Fang
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641, People's Republic of China
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76
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Treatment of an initial infection with clostridium difficile in patients with inflammatory bowel disease. Inflamm Bowel Dis 2013; 19:2223-6. [PMID: 23929262 DOI: 10.1097/mib.0b013e31829b3e1d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
: Although the incidence of Clostridium difficile-associated diarrhea in the general population has increased dramatically over the past decade, an even greater rate of infection exists in patients with inflammatory bowel disease. Susceptibility in this population is likely inherent to the pathophysiology and treatment of these diseases. C. difficile infection can cause serious complications and death. Consequently, early diagnosis and initiation of effective antibacterial therapy is imperative. This article evaluates treatment recommendations for an initial episode of C. difficile infection in patients with inflammatory bowel disease based on the current guidelines and a Cochrane systematic review.
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77
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Armin S, Shamsian S, Drakhshanfar H. Colonization with Clostridium difficile in Children with Cancer. IRANIAN JOURNAL OF PEDIATRICS 2013; 23:473-6. [PMID: 24427503 PMCID: PMC3883379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Accepted: 02/25/2013] [Indexed: 12/02/2022]
Abstract
OBJECTIVE Clostridium difficile is a gram-positive, anaerobic, spore-forming bacillus. Usually it does not cause disease unless a patient who is colonized with toxin-producing strains has been treated with antibiotics, particularly those that change the anaerobic flora of the large intestine. METHODS We investigated in a prospective study intestinal colonization of C. difficile and its toxins in children with malignancy that used different antibiotics and cytotoxic drugs. FINDINGS One hundred fifty-two patients were included in this prospective study. Stool samples were obtained within the first 48 hours after admission and cultured for C. difficile; cytopathic effect of C. difficile was detected on HELA cells, also ELISA test was performed for detection of toxins A and B. 25% of patients had positive culture for C. difficile; 36/38 (92%) revealed positive cytopathic effect on HELA cells. No significant relation was found between age, gender, history of antibiotic consumption and C. difficile positive culture and cytopathic effect on HELA cells. The only relation was seen between cotrimoxazol usage and cytopathic effect on HELA cells (P=0.03). CONCLUSION Although the rate of C. difficile colonization (25.6%) and toxigenic strains (23.7%) in admitted children in hematologic ward is high, the rate of ELISA positive test for toxin A+B was not correspond with culture and cytopatic effect on HELA cell. With respect to sensitivity and specificity of ELISA test, possibility for existence of toxin C with cytopathic effect is high in this type of patients.
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Affiliation(s)
- Shahnaz Armin
- Pediatric Infections Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran,Corresponding Author:Address: Pediatric Infections Research Center, Mofid Children's Hospital, Shariati St., Tehran, 15468-15514, Iran. E-mail:
| | - Shahin Shamsian
- Department of Pediatrics, Mofid Children Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hojatollah Drakhshanfar
- Department of Pediatrics, Mofid Children Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Bassetti M, Villa G, Pecori D, Arzese A, Wilcox M. Epidemiology, diagnosis and treatment of Clostridium difficile infection. Expert Rev Anti Infect Ther 2013; 10:1405-23. [PMID: 23253319 DOI: 10.1586/eri.12.135] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Clostridium difficile infection (CDI) is considered to be the main cause of bacterial infectious diarrhea in nosocomial settings. Since the beginning of the new century a continuous rise in the incidence of severe CDI has been observed worldwide. Even though some CDI cases are not associated with previous antibiotic exposure, this remains as the principal risk factor for the development of CDI. The rate of recurrences represents perhaps one the most challenging aspect on the management of CDI. There are several microbiological tests available, but glutamate dehydrogenase antigen test can be selected as the first screening step in a diagnostic algorithm, with positive samples then confirmed using a toxin(s) test, to distinguish toxinogenic from nontoxinogenic CDI. Although metronidazole and vancomycin are and have been the mainstay treatment options for CDI, there are some unmet medical and therapeutical needs. Usually oral metronidazole is recommended for initial treatment of nonsevere CDI and vancomycin for treatment of severe disease. Fidaxomicin may be considered in patients who cannot tolerate vancomycin, although more data are needed. For treatment of a nonsevere initial recurrence of CDI, oral metronidazole should be used, but for treatment of subsequent recurrences or more severe cases fidaxomicin may be helpful.
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Affiliation(s)
- Matteo Bassetti
- Infectious Diseases Division, Santa Maria Misericordia University Hospital, Udine, Italy.
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79
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Alcalá L. Laboratory tests for diagnosis of Clostridium difficile infection: Past, present, and future. Enferm Infecc Microbiol Clin 2013. [DOI: 10.1016/j.eimc.2012.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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80
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Yoshino Y, Kitazawa T, Ikeda M, Tatsuno K, Yanagimoto S, Okugawa S, Yotsuyanagi H, Ota Y. Clostridium difficile flagellin stimulates toll-like receptor 5, and toxin B promotes flagellin-induced chemokine production via TLR5. Life Sci 2012; 92:211-7. [PMID: 23261530 DOI: 10.1016/j.lfs.2012.11.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 11/05/2012] [Accepted: 11/24/2012] [Indexed: 02/04/2023]
Abstract
AIMS Clostridium difficile is an important pathogen in nosocomial infections. Although C. difficile toxins are considered to be major virulence factors, pathogenesis of C. difficile associated diseases remains to be determined. In this study, we investigated whether C. difficile flagellin is involved in the pathogenesis of C. difficile-associated diseases. MAIN METHODS C. difficile flagellin was extracted from bacterial body by using a combination of ultracentrifugation and low speed centrifugation. Extracted C. difficile flagellin was added to HEK293T cells transiently transfected with pUNO-mcs (empty vector) or pUNO-hTLR5, and NF-kappaB activation was compared by a dual-luciferase assay. The amount of C. difficile flagellin-induced inflammatory mediators such as interleukin-8 and CCL20 was measured by ELISA assay in the culture media of intestinal epithelial cell lines, HT29 cells and Caco-2 cells. Flagellin induced phosphorylation of p38 mitogen-activated protein kinase was examined by Western blotting analysis in Caco-2 cells. The amount of C. difficile flagellin-induced inflammatory mediators in the presence, or absence of C. difficile toxin B was also measured by ELISA assay. KEY FINDINGS C. difficile flagellin induced activation of NF-kappaB in HEK293T cells via toll-like receptor 5. C. difficile flagellin also induced activation of p38 mitogen-activated protein kinase, and promoted the production of interleukin-8 and CCL20 in intestinal epithelial cells via toll-like receptor 5. Pretreatment with toxin B enhanced flagellin-induced cytokine productions. SIGNIFICANCE Our results indicate that toxin B promotes flagellin-induced activation of intestinal epithelial cells, and that C. difficile flagellin may play a role in the occurrence of C. difficile-associated diseases.
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Affiliation(s)
- Yusuke Yoshino
- Department of Infectious Diseases, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Tokyo 173-8606, Japan
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Abstract
Clostridium difficile, a proteolytic Gram-positive anaerobe, has emerged as a significant nosocomial pathogen. Stickland fermentation reactions are thought to be important for growth of C. difficile and appear to influence toxin production. In Stickland reactions, pairs of amino acids donate and accept electrons, generating ATP and reducing power in the process. Reduction of the electron acceptors proline and glycine requires the d-proline reductase (PR) and the glycine reductase (GR) enzyme complexes, respectively. Addition of proline in the medium increases the level of PR protein but decreases the level of GR. We report the identification of PrdR, a protein that activates transcription of the PR-encoding genes in the presence of proline and negatively regulates the GR-encoding genes. The results suggest that PrdR is a central metabolism regulator that controls preferential utilization of proline and glycine to produce energy via the Stickland reactions.
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Chumbler NM, Farrow MA, Lapierre LA, Franklin JL, Haslam D, Goldenring JR, Lacy DB. Clostridium difficile Toxin B causes epithelial cell necrosis through an autoprocessing-independent mechanism. PLoS Pathog 2012; 8:e1003072. [PMID: 23236283 PMCID: PMC3516567 DOI: 10.1371/journal.ppat.1003072] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 10/22/2012] [Indexed: 01/21/2023] Open
Abstract
Clostridium difficile is the most common cause of antibiotic-associated nosocomial infection in the United States. C. difficile secretes two homologous toxins, TcdA and TcdB, which are responsible for the symptoms of C. difficile associated disease. The mechanism of toxin action includes an autoprocessing event where a cysteine protease domain (CPD) releases a glucosyltransferase domain (GTD) into the cytosol. The GTD acts to modify and inactivate Rho-family GTPases. The presumed importance of autoprocessing in toxicity, and the apparent specificity of the CPD active site make it, potentially, an attractive target for small molecule drug discovery. In the course of exploring this potential, we have discovered that both wild-type TcdB and TcdB mutants with impaired autoprocessing or glucosyltransferase activities are able to induce rapid, necrotic cell death in HeLa and Caco-2 epithelial cell lines. The concentrations required to induce this phenotype correlate with pathology in a porcine colonic explant model of epithelial damage. We conclude that autoprocessing and GTD release is not required for epithelial cell necrosis and that targeting the autoprocessing activity of TcdB for the development of novel therapeutics will not prevent the colonic tissue damage that occurs in C. difficile – associated disease. Clostridium difficile is an anaerobic spore-forming bacterium that infects the human colon and causes diarrhea, pseudomembranous colitis, and toxic megacolon. Most people that develop disease symptoms have undergone antibiotic treatment, which alters the normal gut flora and allows C. difficile to flourish. C. difficile secretes two toxins, TcdA and TcdB, that are responsible for the fluid secretion, inflammation, and colonic tissue damage associated with disease. The emergence of hypervirulent strains of C. difficile that are linked to increased morbidity and mortality highlights the need for new therapeutic strategies. One strategy is to inhibit the function of the toxins, thereby decreasing damage to the colon while the patient clears the infection with antibiotics. Toxin function is thought to depend on an autoprocessing event that releases a catalytic ‘effector’ portion of the toxin into the host cell. In the course of trying to identify small molecules that would inhibit such a function, we found that TcdB induces a rapid necrosis in epithelial cells that is not dependent on autoprocessing. The physiological relevance of this observation is confirmed in colonic explants and suggests that inhibiting TcdB autoprocessing will not prevent the colonic tissue damage observed in C. difficile associated diseases.
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Affiliation(s)
- Nicole M. Chumbler
- Chemical and Physical Biology Program, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Melissa A. Farrow
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Lynne A. Lapierre
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Jeffrey L. Franklin
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Department of Cell and Developmental Biology and the Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - David Haslam
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - James R. Goldenring
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Department of Cell and Developmental Biology and the Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - D. Borden Lacy
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail:
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Comparison of a frozen human foreskin fibroblast cell assay to an enzyme immunoassay and toxigenic culture for the detection of toxigenic Clostridium difficile. Diagn Microbiol Infect Dis 2012; 75:42-5. [PMID: 23107315 PMCID: PMC3525856 DOI: 10.1016/j.diagmicrobio.2012.09.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 09/12/2012] [Accepted: 09/20/2012] [Indexed: 12/14/2022]
Abstract
This study set out to validate the Hs27 ReadyCell assay (RCCNA) as an alternative CCNA method compared against a commonly used commercial enzyme immunoassay (EIA) method and toxigenic culture (TC) reference standard. A total of 860 samples were identified from those submitted to the Health Protection Agency microbiology laboratories over a 30-week period. RCCNA performed much better than EIA when using TC as a gold standard, with sensitivities of 90.8% versus 78.6% and positive predictive value of 87.3% to 81.9%, respectively. The Hs27 Human Foreskin Fibroblast ReadyCells are an easy-to-use and a sensitive CCNA method for the detection of toxigenic Clostridium difficile directly from stool. A turnaround time of up to 48 h for a negative result and possible need for repeat testing make it an unsuitable method to be used in most clinical laboratory setting.
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84
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Drug risk factors associated with a sustained outbreak of Clostridium difficile diarrhea in a teaching hospital. Can J Infect Dis 2012; 5:270-5. [PMID: 22346513 DOI: 10.1155/1994/207601] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/1994] [Accepted: 05/15/1994] [Indexed: 11/17/2022] Open
Abstract
A case-control study was undertaken to identify and quantify antimicrobial and nonantimicrobial drug risk factors associated with a sustained outbreak of Clostridium difficile diarrhea on two medical (teaching and nonteaching) units and an oncology unit. In total, 80 cases associated with an endemic clone of toxigenic C difficile were compared with controls. Eighty controls were selected from a group of 290 controls randomly chosen from the outbreak period. The controls were matched to cases according to age, admitting diagnosis and unit of admission. Seventy (88%) patients in the case group received at least one antibiotic before diarrhea, compared with 37 (46%) patients in the control group. Major risk factors implicated in the development of C difficile diarrhea in hospitalized patients were the following antimicrobial agents: ceftazidime (adjusted odds ratio [aor]=26.01, 95% ci 5.67 to 119.19, P=0.0001); cefuroxime (aor=5.17, ci 1.86 to 14.36, P=0.005); ciprofloxacin (aor=3.81, ci 1.05 to 13.79, P=0.04); and clindamycin (aor=15.16, ci 2.93 to 78.44, P=0.004). This is the first time that the use of ciprofloxacin has been linked to the development of C difficile diarrhea. Use of gastrointestinal drugs (ranitidine, famotidine, cimetidine, omeprazole and sucralfate) was also an added risk (aor=3.20, ci 1.39 to 7.34, P=0.01); however, antineoplastic therapy was not significant (P<0.53). Recognition of the specific high risk drugs may spur more restricted use of these agents, which may help in controlling C difficile diarrhea in hospitalized patients.
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Diarrhea recurrence in patients with Clostridium difficile-associated diarrhea: Role of concurrent antibiotics. Can J Infect Dis 2012; 10:287-94. [PMID: 22346388 DOI: 10.1155/1999/102891] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/1998] [Accepted: 09/25/1998] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE To monitor prospectively patients with Clostridium difficile-associated diarrhea (CAD) in a six hundred bed tertiary care hospital to determine which factors influenced the recurrence of the diarrhea. DESIGN A prospective, nonrandomized study. After an initial diagnosis of CAD, patients were interviewed, and each week stool samples and environmental samples were monitored for the presence of toxigenic C difficile for as long as the patients remained in hospital. The relationship of concurrent antibiotics, prolonged fecal excretion of organism or toxin, and environmental contamination was assessed. PATIENTS Over a two-and-a-half year period, 75 consecutive patients with CAD were selected and those who gave their written informed consent were enrolled. A control group to evaluate environmental contamination consisted of 75 patients with diarrhea not associated with C difficile. RESULTS Of the 75 CAD patients, 11 (14.7%) had a recurrence of their diarrhea. Diarrhea recurrence was associated with an increased rate of prolonged excretion of toxigenic organism and/or C difficile toxin(s) (nine of 11 [81.8%] compared with nine of 64 [14.1%]; P≤0.0001; relative risk 14.25; 95% CI 3.383 to 60.023). The risk of diarrhea recurrence was not related to a specific antibiotic but to concurrent therapy. Treatment within 30 days of initial CAD-specific treatment with an antibiotic other than metronidazole or vancomycin occurred significantly more frequently in patients with recurrence of diarrhea compared with those who did not have a recurrence (eight of 11 [72.7%] compared with 22 of 64 [34.4%], P=0.022; relative risk 4; 95% CI 1.153 to 13.881). The environmental contamination rate for toxigenic C difficile in week one in the rooms of patients with diarrhea not caused by C difficile was low (two of 75 [2.6%]) compared with week one data for patients with CAD (14 of 75 [18.7%], P=0.002; relative risk 1.922; 95% CI 1.479 to 2.498). The most frequent site contaminated was the bedpan sprayer (eight of 14 [57.1%]). Pulsed field gel electrophoresis analysis of stool and environmental toxigenic isolates indicated that there was not a single endemic strain of C difficile. CONCLUSIONS This study indicates that the recurrence of diarrhea may be related to concurrent 'other' antibiotics. Although data indicated that there was a correlation between diarrhea recurrence and prolonged fecal excretion of toxin, further studies are required to clarify the clinical significance.
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Comparison of culture, cytotoxin assay and two EIA tests with clinical diagnosis of Clostridium difficile-associated diarrhea. Can J Infect Dis 2012; 5:163-7. [PMID: 22346495 DOI: 10.1155/1994/804205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/1993] [Accepted: 11/02/1993] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE The most common etiology of infectious diarrhea in hospitalized patients is Clostridium difficile. No single laboratory test yields a definitive diagnosis. Four methods were evaluated for their sensitivity and specificity in patients who had clinically defined C difficile-associated diarrhea. METHODS Clinical criteria for C difficile-associated diarrhea were defined. All adult in-hospital patients whose stools were tested for C difficile were prospectively followed. Stools were examined with culture on a selective medium, a commercial cytotoxicity assay (cta), and two commercially available enzyme immunoassays (eias) for toxin A (Meridian) and toxin AB (cbc). RESULTS During the study period 235 stool specimens from 185 patients were tested. Fifty-one patients were positive for C difficile or its markers, cta was most sensitive (80%), whereas cbc-eia was most specific (98%). Differences in the sensitivities of cta and Meridian-eia were minor (80% versus 73.3%) and they were equally specific (95.5%). CONCLUSIONS The sensitivity and specificity of eia for toxin A is similar to other tests. However, due to rapidity and ease of performance, it may be a more practical test for the diagnosis of C difficile-associated diarrhea, especially if the cytotoxin assay is not available.
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Roberts CL, Keita ÅV, Parsons BN, Prorok-Hamon M, Knight P, Winstanley C, O′Kennedy N, Söderholm JD, Rhodes JM, Campbell BJ. Soluble plantain fibre blocks adhesion and M-cell translocation of intestinal pathogens. J Nutr Biochem 2012; 24:97-103. [PMID: 22818716 PMCID: PMC3520008 DOI: 10.1016/j.jnutbio.2012.02.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 02/16/2012] [Accepted: 02/24/2012] [Indexed: 12/24/2022]
Abstract
Dietary fibres may have prebiotic effects mediated by promotion of beneficial bacteria. This study explores the possibility that soluble plant fibre may also improve health by inhibiting epithelial adhesion and translocation by pathogenic bacteria. We have focussed on soluble non-starch polysaccharide (NSP) from plantain bananas (Musa spp.) which previous studies showed to be particularly effective at blocking Escherichia coli epithelial adherence. In vitro and ex vivo studies assessed the ability of plantain NSP to inhibit epithelial cell adhesion and invasion of various bacterial pathogens, and to inhibit their translocation through microfold (M)-cells and human Peyer′s patches mounted in Ussing chambers. Plantain NSP showed dose-related inhibition of epithelial adhesion and M-cell translocation by a range of pathogens. At 5 mg/ml, a concentration readily achievable in the gut lumen, plantain NSP inhibited adhesion to Caco2 cells by Salmonella Typhimurium (85.0±8.2%, P<.01), Shigella sonnei (46.6±29.3%, P<.01), enterotoxigenic E.coli (56.1±23.7%, P<.05) and Clostridium difficile (67.6±12.3%, P<.001), but did not inhibit adhesion by enteropathogenic E.coli. Plantain NSP also inhibited invasion of Caco2 cells by S. Typhimurium (80.2 ± 9.7%) and Sh. sonnei (46.7±13.4%); P<.01. Plantain NSP, 5 mg/ml, also inhibited translocation of S. Typhimurium and Sh. sonnei across M-cells by 73.3±5.2% and 46.4±7.7% respectively (P<.05). Similarly, S. Typhimurium translocation across Peyer′s patches was reduced 65.9±8.1% by plantain NSP (P<.01). Soluble plantain fibre can block epithelial adhesion and M-cell translocation of intestinal pathogens. This represents an important novel mechanism by which soluble dietary fibres can promote intestinal health and prevent infective diarrhoea.
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Affiliation(s)
- Carol L. Roberts
- Gastroenterology, Institute of Translational Medicine, University of Liverpool, L69 3GE Liverpool, UK
| | - Åsa V. Keita
- Clinical and Experimental Medicine, Division of Surgery, Faculty of Health Sciences, Linköping University, 581 83 Linköping, Sweden
| | - Bryony N. Parsons
- Gastroenterology, Institute of Translational Medicine, University of Liverpool, L69 3GE Liverpool, UK
| | - Maelle Prorok-Hamon
- Gastroenterology, Institute of Translational Medicine, University of Liverpool, L69 3GE Liverpool, UK
| | - Paul Knight
- Gastroenterology, Institute of Translational Medicine, University of Liverpool, L69 3GE Liverpool, UK
| | - Craig Winstanley
- Institute of Infection and Global Health, University of Liverpool, L69 3GA, UK
| | - Niamh O′Kennedy
- Provexis Plc, c/o Rowett Institute of Nutrition and Health, AB21 9S, Aberdeen, UK
| | - Johan D. Söderholm
- Clinical and Experimental Medicine, Division of Surgery, Faculty of Health Sciences, Linköping University, 581 83 Linköping, Sweden
| | - Jonathan M. Rhodes
- Gastroenterology, Institute of Translational Medicine, University of Liverpool, L69 3GE Liverpool, UK
| | - Barry J. Campbell
- Gastroenterology, Institute of Translational Medicine, University of Liverpool, L69 3GE Liverpool, UK
- Corresponding author. Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, L69 3GE, Liverpool, UK. Tel.: + 44 0 151 794 6829; fax: + 44 0 151 794 6825.
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Barr BS, Waldridge BM, Morresey PR, Reed SM, Clark C, Belgrave R, Donecker JM, Weigel DJ. Antimicrobial-associated diarrhoea in three equine referral practices. Equine Vet J 2012; 45:154-8. [PMID: 22779907 DOI: 10.1111/j.2042-3306.2012.00595.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
REASONS FOR PERFORMING STUDY Although antimicrobial-associated diarrhoea (AAD) is the most frequently observed adverse effect of antimicrobial therapy in horses, few multicentred studies on the prevalence of AAD have been performed. OBJECTIVES To determine the prevalence of AAD in horses that developed diarrhoea after antimicrobial treatment for nondiarrhoeic conditions and identify the antimicrobials used. METHODS The 2009 database of 3 referral hospitals was searched to identify nonhospitalised horses (weanling age or older) treated with antimicrobials for nongastrointestinal conditions. Horses with these criteria that presented with diarrhoea during 2009 were included in the study. Additional information, including antimicrobial administered and results of faecal pathogen testing, was gathered on each hospitalised case. RESULTS Of the 5251 horses treated with antimicrobials for nongastrointestinal signs, 32 were diagnosed with probable AAD, a prevalence of 0.6% (95% confidence interval: 0.43-0.86%). The AAD-diagnosed horses had an 18.8% (6/32) mortality rate. Horses with AAD had been treated for an average of 4.2 days. The most frequently used antimicrobials in horses with AAD were gentamicin in combination with penicillin (n = 7), enrofloxacin (n = 7) and doxycycline (n = 4). Clostridium difficile was identified in faecal samples from 4 horses, 2 of which died and Salmonella from 3 horses. CONCLUSIONS Results indicated that the prevalence of AAD is low. Any antimicrobial class commonly used in equine practice is a potential cause of equine AAD. Other risk factors, such as opportunistic enteropathogens, may play a part in the development of diarrhoea secondary to antimicrobial usage. POTENTIAL RELEVANCE Although the risk of equine AAD is low, this sequela of antimicrobial treatment is possible especially when opportunistic enteropathogens or other risk factors are present. Because drugs from any antimicrobial class can be potentially involved in AAD, clinicians have additional incentive to ensure the judicious use of antimicrobial agents.
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Affiliation(s)
- B S Barr
- Rood and Riddle Equine Hospital, Kentucky, USA
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Marozsan AJ, Ma D, Nagashima KA, Kennedy BJ, Kang YK, Arrigale RR, Donovan GP, Magargal WW, Maddon PJ, Olson WC. Protection against Clostridium difficile infection with broadly neutralizing antitoxin monoclonal antibodies. J Infect Dis 2012; 206:706-13. [PMID: 22732923 DOI: 10.1093/infdis/jis416] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The spore-forming bacterium Clostridium difficile represents the principal cause of hospital-acquired diarrhea and pseudomembranous colitis worldwide. C. difficile infection (CDI) is mediated by 2 bacterial toxins, A and B; neutralizing these toxins with monoclonal antibodies (mAbs) provides a potential nonantibiotic strategy for combating the rising prevalence, severity, and recurrence of CDI. Novel antitoxin mAbs were generated in mice and were humanized. The humanized antitoxin A mAb PA-50 and antitoxin B mAb PA-41 have picomolar potencies in vitro and bind to novel regions of the respective toxins. In a hamster model for CDI, 95% of animals treated with a combination of humanized PA-50 and PA-41 showed long-term survival relative to 0% survival of animals treated with standard antibiotics or comparator mAbs. These humanized mAbs provide insight into C. difficile intoxication and hold promise as potential nonantibiotic agents for improving clinical management of CDI.
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90
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Leggett MJ, McDonnell G, Denyer SP, Setlow P, Maillard JY. Bacterial spore structures and their protective role in biocide resistance. J Appl Microbiol 2012; 113:485-98. [PMID: 22574673 DOI: 10.1111/j.1365-2672.2012.05336.x] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The structure and chemical composition of bacterial spores differ considerably from those of vegetative cells. These differences largely account for the unique resistance properties of the spore to environmental stresses, including disinfectants and sterilants, resulting in the emergence of spore-forming bacteria such as Clostridium difficile as major hospital pathogens. Although there has been considerable work investigating the mechanisms of action of many sporicidal biocides against Bacillus subtilis spores, there is far less information available for other species and particularly for various Clostridia. This paucity of information represents a major gap in our knowledge given the importance of Clostridia as human pathogens. This review considers the main spore structures, highlighting their relevance to spore resistance properties and detailing their chemical composition, with a particular emphasis on the differences between various spore formers. Such information will be vital for the rational design and development of novel sporicidal chemistries with enhanced activity in the future.
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Affiliation(s)
- M J Leggett
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK
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91
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Kim J, Pai H, Seo MR, Kang JO. Clinical and microbiologic characteristics of tcdA-negative variant Clostridium difficile infections. BMC Infect Dis 2012; 12:109. [PMID: 22571633 PMCID: PMC3420311 DOI: 10.1186/1471-2334-12-109] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 05/09/2012] [Indexed: 01/05/2023] Open
Abstract
Background The tcdA-negative variant (A-B+) of Clostridium difficile is prevalent in East Asian countries. However, the risk factors and clinical characteristics of A-B+C. difficile infections (CDI) are not clearly documented. The objective of this study was to investigate these characteristics. Methods From September 2008 through January 2010, the clinical characteristics, medication history and treatment outcomes of CDI patients were recorded prospectively. Toxin characterization and antibiotic susceptibility tests were performed on stool isolates of C. difficile. Results During the study period, we identified 22 cases of CDI caused by tcdA-negative tcdB-positive (A-B+) strains and 105 cases caused by tcdA-positive tcdB-positive (A+B+) strains. There was no significant difference in disease severity or clinical characteristics between the two groups. Previous use of clindamycin and young age were identified as significant risk factors for the acquisition of A-B+ CDI (OR = 4.738, 95% CI 1.48–15.157, p = 0.009 and OR = 0.966, 95% CI 0.935–0.998, p = 0.038, respectively) in logistic regression. Rates of resistance to clindamycin were 100% and 69.6% in the A-B+ and A+B+ isolates, respectively (p = 0.006), and the ermB gene was identified in 17 of 21 A-B+ isolates (81%). Resistance to moxifloxacin was also more frequent in the A-B+ than in the A+B+ isolates (95.2% vs. 63.7%, p = 0.004). Conclusions The clinical course of A-B+ CDI is not different from that of A+B+ CDI. Clindamycin use is a significant risk factor for the acquisition of tcdA-negative variant strains.
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Affiliation(s)
- Jieun Kim
- Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea
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92
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Pruitt RN, Lacy DB. Toward a structural understanding of Clostridium difficile toxins A and B. Front Cell Infect Microbiol 2012; 2:28. [PMID: 22919620 PMCID: PMC3417631 DOI: 10.3389/fcimb.2012.00028] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 02/27/2012] [Indexed: 12/17/2022] Open
Abstract
Clostridium difficile is a toxin-producing bacterium that is a frequent cause of hospital-acquired and antibiotic-associated diarrhea. The incidence, severity, and costs associated with C. difficile associated disease are substantial and increasing, making C. difficile a significant public health concern. The two primary toxins, TcdA and TcdB, disrupt host cell function by inactivating small GTPases that regulate the actin cytoskeleton. This review will discuss the role of these two toxins in pathogenesis and the structural and molecular mechanisms by which they intoxicate cells. A focus will be placed on recent publications highlighting mechanistic similarities and differences between TcdA, TcdB, and different TcdB variants.
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Affiliation(s)
- Rory N Pruitt
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville TN, USA
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93
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Retallack DM, Jin H, Chew L. Reliable protein production in a Pseudomonas fluorescens expression system. Protein Expr Purif 2012; 81:157-65. [DOI: 10.1016/j.pep.2011.09.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 09/20/2011] [Accepted: 09/20/2011] [Indexed: 10/17/2022]
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94
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Walter Zea J, Lina Salazar C. Enfermedad asociada a Clostridium difficile: prevalencia y diagnóstico por laboratorio. INFECTIO 2012. [DOI: 10.1016/s0123-9392(12)70016-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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95
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Lancaster JW, Matthews SJ. Fidaxomicin: The Newest Addition to the Armamentarium Against Clostridium difficile Infections. Clin Ther 2012; 34:1-13. [DOI: 10.1016/j.clinthera.2011.12.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 12/06/2011] [Accepted: 12/09/2011] [Indexed: 01/05/2023]
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Effect of a synbiotic yogurt on levels of fecal bifidobacteria, clostridia, and enterobacteria. Appl Environ Microbiol 2011; 78:933-40. [PMID: 22101054 DOI: 10.1128/aem.05848-11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
While ingestion of synbiotic yogurts containing Bifidobacterium animalis subsp. lactis and inulin is increasing, their effect on certain microbial groups in the human intestine is unclear. To further investigate this, a large-scale, crossover-design, placebo-controlled study was utilized to evaluate the effect of a synbiotic yogurt containing B. animalis subsp. lactis Bb-12 and inulin on the human intestinal bifidobacteria, clostridia, and enterobacteria. Fecal samples were collected at 14 time points from 46 volunteers who completed the study, and changes in the intestinal bacterial levels were monitored using real-time PCR. Strain Bb-12 could not be detected in feces after 2 weeks of washout. A live/dead PCR procedure indicated that the Bb-12 strain detected in the fecal samples was alive. A significant increase (P < 0.001) in the total bifidobacterial numbers was seen in both groups of subjects during the final washout period compared to the prefeeding period. This increase in total bifidobacteria corresponded with a significant decrease (P < 0.05) in numbers of clostridia but not enterobacteria. No significant differences in numbers of bifidobacteria, clostridia, or enterobacteria were observed between the probiotic and placebo groups during any of the feeding periods. However, subgrouping subjects based on lower initial bifidobacterial numbers or higher initial clostridial numbers did show corresponding significant differences between the synbiotic yogurt and placebo groups. This was not observed for a subgroup with higher initial enterobacterial numbers. While this synbiotic yogurt can increase bifidobacterial numbers and decrease clostridial numbers (but not enterobacterial numbers) in some individuals, it cannot modulate these microbial groups in the majority of individuals.
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Novel one-step method for detection and isolation of active-toxin-producing Clostridium difficile strains directly from stool samples. J Clin Microbiol 2011; 49:4219-24. [PMID: 21976761 DOI: 10.1128/jcm.01033-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The alarming emergence of hypervirulent strains of Clostridium difficile with increased toxin production, severity of disease, morbidity, and mortality emphasizes the need for a culture method that permits simultaneous isolation and detection of virulent strains. The C. difficile toxins A and B are critical virulence factors, and strains can either be toxin-producing (virulent) or non-toxin-producing (nonvirulent). Strains that are isolated from human infections generally produce either toxin A or toxin B or both. The methods currently available for culturing C. difficile do not differentiate strains that produce active toxins from strains that do not produce toxins or produce inactive toxins. As a result, the identification and isolation of toxin-producing strains from stool is currently a two-step process. First, the stool is plated on a selective medium, and then suspected colonies are analyzed for toxin production or the presence of the toxin genes. We describe here a novel selective and differential culture method, the Cdifftox plate assay, which combines in a single step the specific isolation of C. difficile strains and the detection of active toxin. This assay was developed based on our recent finding that the A and B toxins of C. difficile cleave chromogenic substrates that have stereochemical characteristics similar to their natural substrate, UDP-glucose. The Cdifftox plate assay is shown here to be extremely accurate (99.8% effective) in detecting toxin-producing strains through the analysis of 528 C. difficile isolates selected from 50 tissue culture cytotoxicity assay-positive clinical stool samples. The Cdifftox plate assay advances and improves the culture approach such that only C. difficile strains will grow on this agar, and virulent strains producing active toxins can be differentiated from nonvirulent strains, which do not produce active toxins. This new method reduces the time and effort required to isolate and confirm toxin-producing C. difficile strains.
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Alcalá L, Marín M, Martín A, Sánchez-Somolinos M, Catalán P, Peláez M, Bouza E. Laboratory diagnosis of Clostridium difficile infection in Spain: a population-based survey. J Hosp Infect 2011; 79:13-7. [DOI: 10.1016/j.jhin.2011.05.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Accepted: 05/11/2011] [Indexed: 11/30/2022]
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Tenover FC, Baron EJ, Peterson LR, Persing DH. Laboratory diagnosis of Clostridium difficile infection can molecular amplification methods move us out of uncertainty? J Mol Diagn 2011; 13:573-82. [PMID: 21854871 DOI: 10.1016/j.jmoldx.2011.06.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 05/16/2011] [Accepted: 06/14/2011] [Indexed: 12/18/2022] Open
Abstract
The laboratory diagnosis of Clostridium difficile infection (CDI) continues to be challenging. Recent guidelines from professional societies in the United States note that enzyme immunoassays for toxins A and B do not have adequate sensitivity to be used alone for detecting CDI, yet the optimal method for diagnosing this infection remains unclear. Nucleic acid amplification tests (NAATs) that target chromosomal toxin genes (usually the toxin B gene, tcdB) show high sensitivity and specificity, provide rapid results, and are amenable to both batch and on-demand testing, but these tests were not universally recommended for routine use in the recent guidelines. Rather, two-step algorithms that use glutamate dehydrogenase (GDH) assays to screen for C. difficile in stool specimens, followed by either direct cytotoxin testing or culture to identify toxin-producing C. difficile isolates, were recommended in one guideline and either GDH algorithms or NAATs were recommended in another guideline. Unfortunately, neither culture nor direct cytotoxin testing is widely available. In addition, this two-step approach requires 48 to 92 hours to complete, which may delay the initiation of therapy and critical infection control measures. Recent studies also show the sensitivity of several GDH assays to be <90%. This review considers the role of NAATs for diagnosing CDI and explores their potential advantages over two-step algorithms, including shorter time to results, while providing comparable, if not superior, accuracy.
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Demarest SJ, Hariharan M, Elia M, Salbato J, Jin P, Bird C, Short JM, Kimmel BE, Dudley M, Woodnutt G, Hansen G. Neutralization of Clostridium difficile toxin A using antibody combinations. MAbs 2011; 2:190-8. [PMID: 20150758 DOI: 10.4161/mabs.2.2.11220] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The pathogenicity of Clostridium difficile (C. difficile) is mediated by the release of two toxins, A and B. Both toxins contain large clusters of repeats known as cell wall binding (CWB) domains responsible for binding epithelial cell surfaces. Several murine monoclonal antibodies were generated against the CWB domain of toxin A and screened for their ability to neutralize the toxin individually and in combination. Three antibodies capable of neutralizing toxin A all recognized multiple sites on toxin A, suggesting that the extent of surface coverage may contribute to neutralization. Combination of two noncompeting antibodies, denoted 3358 and 3359, enhanced toxin A neutralization over saturating levels of single antibodies. Antibody 3358 increased the level of detectable CWB domain on the surface of cells, while 3359 inhibited CWB domain cell surface association. These results suggest that antibody combinations that cover a broader epitope space on the CWB repeat domains of toxin A (and potentially toxin B) and utilize multiple mechanisms to reduce toxin internalization may provide enhanced protection against C. difficile-associated diarrhea.
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