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Pillai SP, Hill KK, Gans J, Smith TJ. Real-time PCR assays that detect genes for botulinum neurotoxin A-G subtypes. Front Microbiol 2024; 15:1382056. [PMID: 38873139 PMCID: PMC11169944 DOI: 10.3389/fmicb.2024.1382056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Accepted: 04/22/2024] [Indexed: 06/15/2024] Open
Abstract
The role of Real-Time PCR assays for surveillance and rapid screening for pathogens is garnering more and more attention because of its versatility and ease of adoption. The goal of this study was to design, test, and evaluate Real-Time TaqMan PCR assays for the detection of botulinum neurotoxin (bont/A-G) genes from currently recognized BoNT subtypes. Assays were computationally designed and then laboratory tested for sensitivity and specificity using DNA preparations containing bont genes from 82 target toxin subtypes, including nine bivalent toxin types; 31 strains representing other clostridial species; and an extensive panel that consisted of DNA from a diverse set of prokaryotic (bacterial) and eukaryotic (fungal, protozoan, plant, and animal) species. In addition to laboratory testing, the assays were computationally evaluated using in silico analysis for their ability to detect bont gene sequences from recently identified toxin subtypes. Seventeen specific assays (two for each of the bont/C, bont/D, bont/E, and bont/G subtypes and three for each of the bont/A, bont/B, and bont/F subtypes) were designed and evaluated for their ability to detect bont genes encoding multiple subtypes from all seven serotypes. These assays could provide an additional tool for the detection of botulinum neurotoxins in clinical, environmental and food samples that can complement other existing methods used in clinical diagnostics, regulatory, public health, and research laboratories.
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Affiliation(s)
- Segaran P. Pillai
- Office of the Commissioner, Food and Drug Administration, Department of Health and Human Services, Silver Spring, MD, United States
| | - Karen K. Hill
- Los Alamos National Laboratory, Bioscience Division, Los Alamos, NM, United States
| | - Jason Gans
- Los Alamos National Laboratory, Bioscience Division, Los Alamos, NM, United States
| | - Theresa J. Smith
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, United States
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Chellapandi P, Prisilla A. PCR-based molecular diagnosis of botulism (types C and D) outbreaks in aquatic birds. ANN MICROBIOL 2018. [DOI: 10.1007/s13213-018-1390-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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3
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Le Maréchal C, Rouxel S, Ballan V, Houard E, Poezevara T, Bayon-Auboyer MH, Souillard R, Morvan H, Baudouard MA, Woudstra C, Mazuet C, Le Bouquin S, Fach P, Popoff M, Chemaly M. Development and Validation of a New Reliable Method for the Diagnosis of Avian Botulism. PLoS One 2017; 12:e0169640. [PMID: 28076405 PMCID: PMC5226734 DOI: 10.1371/journal.pone.0169640] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 12/20/2016] [Indexed: 11/18/2022] Open
Abstract
Liver is a reliable matrix for laboratory confirmation of avian botulism using real-time PCR. Here, we developed, optimized, and validated the analytical steps preceding PCR to maximize the detection of Clostridium botulinum group III in avian liver. These pre-PCR steps included enrichment incubation of the whole liver (maximum 25 g) at 37°C for at least 24 h in an anaerobic chamber and DNA extraction using an enzymatic digestion step followed by a DNA purification step. Conditions of sample storage before analysis appear to have a strong effect on the detection of group III C. botulinum strains and our results recommend storage at temperatures below -18°C. Short-term storage at 5°C is possible for up to 24 h, but a decrease in sensitivity was observed at 48 h of storage at this temperature. Analysis of whole livers (maximum 25 g) is required and pooling samples before enrichment culturing must be avoided. Pooling is however possible before or after DNA extraction under certain conditions. Whole livers should be 10-fold diluted in enrichment medium and homogenized using a Pulsifier® blender (Microgen, Surrey, UK) instead of a conventional paddle blender. Spiked liver samples showed a limit of detection of 5 spores/g liver for types C and D and 250 spores/g for type E. Using the method developed here, the analysis of 268 samples from 73 suspected outbreaks showed 100% specificity and 95.35% sensitivity compared with other PCR-based methods considered as reference. The mosaic type C/D was the most common neurotoxin type found in examined samples, which included both wild and domestic birds.
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Affiliation(s)
- Caroline Le Maréchal
- ANSES, Laboratoire de Ploufragan – Plouzané, Unité Hygiène et qualité des produits avicoles et porcins, Université Bretagne-Loire, Ploufragan, France
| | - Sandra Rouxel
- ANSES, Laboratoire de Ploufragan – Plouzané, Unité Hygiène et qualité des produits avicoles et porcins, Université Bretagne-Loire, Ploufragan, France
| | - Valentine Ballan
- ANSES, Laboratoire de Ploufragan – Plouzané, Unité Hygiène et qualité des produits avicoles et porcins, Université Bretagne-Loire, Ploufragan, France
| | - Emmanuelle Houard
- ANSES, Laboratoire de Ploufragan – Plouzané, Unité Hygiène et qualité des produits avicoles et porcins, Université Bretagne-Loire, Ploufragan, France
| | - Typhaine Poezevara
- ANSES, Laboratoire de Ploufragan – Plouzané, Unité Hygiène et qualité des produits avicoles et porcins, Université Bretagne-Loire, Ploufragan, France
| | | | - Rozenn Souillard
- ANSES, Laboratoire de Ploufragan – Plouzané, Unité d’Epidémiologie et bien-être en aviculture et cuniculture, Université Bretagne-Loire, Ploufragan, France
| | | | | | - Cédric Woudstra
- ANSES, Laboratoire de sécurité des aliments, Maisons Alfort, France
| | | | - Sophie Le Bouquin
- ANSES, Laboratoire de Ploufragan – Plouzané, Unité d’Epidémiologie et bien-être en aviculture et cuniculture, Université Bretagne-Loire, Ploufragan, France
| | - Patrick Fach
- ANSES, Laboratoire de sécurité des aliments, Maisons Alfort, France
| | - Michel Popoff
- Institut Pasteur, Bactéries anaérobies et Toxines, Paris, France
| | - Marianne Chemaly
- ANSES, Laboratoire de Ploufragan – Plouzané, Unité Hygiène et qualité des produits avicoles et porcins, Université Bretagne-Loire, Ploufragan, France
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Woudstra C, Tevell Åberg A, Skarin H, Anniballi F, De Medici D, Bano L, Koene M, Löfström C, Hansen T, Hedeland M, Fach P. Animal botulism outcomes in the AniBioThreat project. Biosecur Bioterror 2014; 11 Suppl 1:S177-82. [PMID: 23971804 DOI: 10.1089/bsp.2012.0074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Botulism disease in both humans and animals is a worldwide concern. Botulinum neurotoxins produced by Clostridium botulinum and other Clostridium species are the most potent biological substances known and are responsible for flaccid paralysis leading to a high mortality rate. Clostridium botulinum and botulinum neurotoxins are considered potential weapons for bioterrorism and have been included in the Australia Group List of Biological Agents. In 2010 the European Commission (DG Justice, Freedom and Security) funded a 3-year project named AniBioThreat to improve the EU's capacity to counter animal bioterrorism threats. A detection portfolio with screening methods for botulism agents and incidents was needed to improve tracking and tracing of accidental and deliberate contamination of the feed and food chain with botulinum neurotoxins and other Clostridia. The complexity of this threat required acquiring new genetic information to better understand the diversity of these Clostridia and develop detection methods targeting both highly specific genetic markers of these Clostridia and the neurotoxins they are able to produce. Several European institutes participating in the AniBioThreat project collaborated on this program to achieve these objectives. Their scientific developments are discussed here.
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Vanhomwegen J, Berthet N, Mazuet C, Guigon G, Vallaeys T, Stamboliyska R, Dubois P, Kennedy GC, Cole ST, Caro V, Manuguerra JC, Popoff MR. Application of high-density DNA resequencing microarray for detection and characterization of botulinum neurotoxin-producing clostridia. PLoS One 2013; 8:e67510. [PMID: 23818983 PMCID: PMC3688605 DOI: 10.1371/journal.pone.0067510] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 05/22/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Clostridium botulinum and related clostridia express extremely potent toxins known as botulinum neurotoxins (BoNTs) that cause severe, potentially lethal intoxications in humans. These BoNT-producing bacteria are categorized in seven major toxinotypes (A through G) and several subtypes. The high diversity in nucleotide sequence and genetic organization of the gene cluster encoding the BoNT components poses a great challenge for the screening and characterization of BoNT-producing strains. METHODOLOGY/PRINCIPAL FINDINGS In the present study, we designed and evaluated the performances of a resequencing microarray (RMA), the PathogenId v2.0, combined with an automated data approach for the simultaneous detection and characterization of BoNT-producing clostridia. The unique design of the PathogenID v2.0 array allows the simultaneous detection and characterization of 48 sequences targeting the BoNT gene cluster components. This approach allowed successful identification and typing of representative strains of the different toxinotypes and subtypes, as well as the neurotoxin-producing C. botulinum strain in a naturally contaminated food sample. Moreover, the method allowed fine characterization of the different neurotoxin gene cluster components of all studied strains, including genomic regions exhibiting up to 24.65% divergence with the sequences tiled on the arrays. CONCLUSIONS/SIGNIFICANCE The severity of the disease demands rapid and accurate means for performing risk assessments of BoNT-producing clostridia and for tracing potentials sources of contamination in outbreak situations. The RMA approach constitutes an essential higher echelon component in a diagnostics and surveillance pipeline. In addition, it is an important asset to characterise potential outbreak related strains, but also environment isolates, in order to obtain a better picture of the molecular epidemiology of BoNT-producing clostridia.
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Affiliation(s)
- Jessica Vanhomwegen
- Institut Pasteur, Laboratory for Urgent Responses to Biological Threats, Paris, France
| | - Nicolas Berthet
- Institut Pasteur, Epidemiology and Pathophysiology of Oncogenic Viruses, Paris, France
- CNRS, UMR3569, Paris, France
| | | | - Ghislaine Guigon
- Institut Pasteur, Genotyping of Pathogens and Public Health, Paris, France
| | - Tatiana Vallaeys
- CNRS – CC093 Université Montpellier II, UMR5119 Ecosystèmes lagunaires, Montpellier, France
| | - Rayna Stamboliyska
- Department of Biology II, University of Munich (LMU), Planegg-Martinsried, Germany
| | - Philippe Dubois
- Institut Pasteur, Laboratory for Urgent Responses to Biological Threats, Paris, France
| | - Giulia C. Kennedy
- Department of Research and Development, Veracyte, Inc., South San Francisco, California, United States of America
| | - Stewart T. Cole
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Valérie Caro
- Institut Pasteur, Genotyping of Pathogens and Public Health, Paris, France
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Genetic diversity of the flagellin genes of Clostridium botulinum groups I and II. Appl Environ Microbiol 2013; 79:3926-32. [PMID: 23603687 DOI: 10.1128/aem.00686-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) are produced by phenotypically and genetically different Clostridium species, including Clostridium botulinum and some strains of Clostridium baratii (serotype F) and Clostridium butyricum (serotype E). BoNT-producing clostridia responsible for human botulism encompass strains of group I (secreting proteases, producing toxin serotype A, B, or F, and growing optimally at 37°C) and group II (nonproteolytic, producing toxin serotype E, B, or F, and growing optimally at 30°C). Here we report the development of real-time PCR assays for genotyping C. botulinum strains of groups I and II based on flaVR (variable region sequence of flaA) sequences and the flaB gene. Real-time PCR typing of regions flaVR1 to flaVR10 and flaB was optimized and validated with 62 historical and Canadian C. botulinum strains that had been previously typed. Analysis of 210 isolates of European origin allowed the identification of four new C. botulinum flaVR types (flaVR11 to flaVR14) and one new flaVR type specific to C. butyricum type E (flaVR15). The genetic diversity of the flaVR among C. botulinum strains investigated in the present study reveals the clustering of flaVR types into 5 major subgroups. Subgroups 1, 3, and 4 contain proteolytic Clostridium botulinum, subgroup 2 is made up of nonproteolytic C. botulinum only, and subgroup 5 is specific to C. butyricum type E. The genetic variability of the flagellin genes carried by C. botulinum and the possible association of flaVR types with certain geographical areas make gene profiling of flaVR and flaB promising in molecular surveillance and epidemiology of C. botulinum.
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Fratamico PM, Bagi LK. Detection of Shiga toxin-producing Escherichia coli in ground beef using the GeneDisc real-time PCR system. Front Cell Infect Microbiol 2012; 2:152. [PMID: 23267438 PMCID: PMC3526733 DOI: 10.3389/fcimb.2012.00152] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 11/15/2012] [Indexed: 01/06/2023] Open
Abstract
Escherichia coli O157:H7 and certain non-O157 Shiga toxin-producing Escherichia coli (STEC) serogroups have emerged as important public health threats. The development of methods for rapid and reliable detection of this heterogeneous group of pathogens has been challenging. GeneDisc real-time PCR assays were evaluated for detection of the stx(1), stx(2), eae, and ehxA genes and a gene that identifies the O157 serogroup followed by a second GeneDisc assay targeting serogroup-specific genes of STEC O26, O45, O91, O103, O111, O113, O121, O145, and O157. The ability to detect the STEC serogroups in ground beef samples artificially inoculated at a level of ca. 2-20 CFU/25 g and subjected to enrichment in mTSB or buffered peptone water (BPW) was similar. Following enrichment, all inoculated ground beef samples showed amplification of the correct set of target genes carried by each strain. Samples inoculated with STEC serogroups O26, O45, O103, O111, O121, O145, and O157 were subjected to immunomagnetic separation (IMS), and isolation was achieved by plating onto Rainbow agar O157. Colonies were confirmed by PCR assays targeting stx(1), stx(2), eae, and serogroup-specific genes. Thus, this work demonstrated that GeneDisc assays are rapid, sensitive, and reliable and can be used for screening ground beef and potentially other foods for STEC serogroups that are important food-borne pathogens worldwide.
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Affiliation(s)
- Pina M Fratamico
- Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture Wyndmoor, PA, USA.
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Sevenier V, Delannoy S, André S, Fach P, Remize F. Prevalence of Clostridium botulinum and thermophilic heat-resistant spores in raw carrots and green beans used in French canning industry. Int J Food Microbiol 2012; 155:263-8. [DOI: 10.1016/j.ijfoodmicro.2012.02.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 02/13/2012] [Accepted: 02/16/2012] [Indexed: 10/28/2022]
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Neurotoxin gene profiling of clostridium botulinum types C and D native to different countries within Europe. Appl Environ Microbiol 2012; 78:3120-7. [PMID: 22344654 DOI: 10.1128/aem.07568-11] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Clostridium botulinum types C and D, as well as their mosaic variants C-D and D-C, are associated with avian and mammalian botulism. This study reports on the development of low-density macroarrays based on the GeneDisc cycler platform (Pall-GeneDisc Technologies) applied to the simultaneous detection of the C. botulinum subtypes C, C-D, D, and D-C. The limit of detection of the PCR assays was 38 fg of total DNA, corresponding to 15 genome copies. Artificially contaminated samples of cecum showed a limit of detection below 50 spores/g. The tests were performed with a large variety of bacterial strains, including C. botulinum types C (n = 12), C-D (n = 29), D (n = 5), and D-C (n = 10), other botulinum neurotoxin (BoNT)-producing Clostridium strains (n = 20), non-BoNT-producing clostridia (n = 20), and other bacterial species (n = 23), and showed a high specificity. These PCR assays were compared to previously published real-time PCRs for the detection of C. botulinum in 292 samples collected from cases of botulism events in four European regions. The majority of the samples originated from wild birds (n = 108), poultry (n = 60), and bovines (n = 56). Among the 292 samples, 144 were positive for either the bont/C-D or the bont/D-C gene by using the GeneDisc arrays. The reliability of the results tallied to 97.94%. Interestingly, only BoNT mosaics, types C-D and D-C, were found in naturally contaminated samples whatever their animal origin and their geographical location. Further investigations should now be performed in order to check that mosaic types dominate in Europe and that acquisition of mosaic types helps in survival or adaptation to particular niche.
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Antibodies against a synthetic peptide designed to mimic a surface area of the H chain of botulinum neurotoxin A. Immunol Lett 2012; 142:20-7. [DOI: 10.1016/j.imlet.2011.11.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 11/07/2011] [Accepted: 11/14/2011] [Indexed: 11/23/2022]
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Dorner MB, Schulz KM, Kull S, Dorner BG. Complexity of Botulinum Neurotoxins: Challenges for Detection Technology. Curr Top Microbiol Immunol 2012. [DOI: 10.1007/978-3-662-45790-0_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Stiles BG, Wigelsworth DJ, Popoff MR, Barth H. Clostridial binary toxins: iota and C2 family portraits. Front Cell Infect Microbiol 2011; 1:11. [PMID: 22919577 PMCID: PMC3417380 DOI: 10.3389/fcimb.2011.00011] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 11/10/2011] [Indexed: 02/04/2023] Open
Abstract
There are many pathogenic Clostridium species with diverse virulence factors that include protein toxins. Some of these bacteria, such as C. botulinum, C. difficile, C. perfringens, and C. spiroforme, cause enteric problems in animals as well as humans. These often fatal diseases can partly be attributed to binary protein toxins that follow a classic AB paradigm. Within a targeted cell, all clostridial binary toxins destroy filamentous actin via mono-ADP-ribosylation of globular actin by the A component. However, much less is known about B component binding to cell-surface receptors. These toxins share sequence homology amongst themselves and with those produced by another Gram-positive, spore-forming bacterium also commonly associated with soil and disease: Bacillus anthracis. This review focuses upon the iota and C2 families of clostridial binary toxins and includes: (1) basics of the bacterial source; (2) toxin biochemistry; (3) sophisticated cellular uptake machinery; and (4) host–cell responses following toxin-mediated disruption of the cytoskeleton. In summary, these protein toxins aid diverse enteric species within the genus Clostridium.
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Affiliation(s)
- Bradley G Stiles
- Biology Department, Wilson College, Chambersburg, PA, USA; Integrated Toxicology Division, Medical Research Institute of Infectious Diseases, Frederick, MD, USA.
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Knutsson R. A tracing tool portfolio to detect Bacillus anthracis, Clostridium botulinum and Noroviruses: bioterrorism is a food safety and security issue. Int J Food Microbiol 2010; 145 Suppl 1:S121-2. [PMID: 21324542 DOI: 10.1016/j.ijfoodmicro.2010.12.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Rickard Knutsson
- Department of Bacteriology, National Veterinary Institute, SVA, Sweden.
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