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Zhang J, Gao P, Wu Y, Yan X, Ye C, Liang W, Yan M, Xu X, Jiang H. Identification of foodborne pathogenic bacteria using confocal Raman microspectroscopy and chemometrics. Front Microbiol 2022; 13:874658. [PMID: 36419427 PMCID: PMC9676656 DOI: 10.3389/fmicb.2022.874658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 10/17/2022] [Indexed: 11/04/2023] Open
Abstract
Rapid and accurate identification of foodborne pathogenic bacteria is of great importance because they are often responsible for the majority of serious foodborne illnesses. The confocal Raman microspectroscopy (CRM) is a fast and easy-to-use method known for its effectiveness in detecting and identifying microorganisms. This study demonstrates that CRM combined with chemometrics can serve as a rapid, reliable, and efficient method for the detection and identification of foodborne pathogenic bacteria without any laborious pre-treatments. Six important foodborne pathogenic bacteria including S. flexneri, L. monocytogenes, V. cholerae, S. aureus, S. typhimurium, and C. botulinum were investigated with CRM. These pathogenic bacteria can be differentiated based on several characteristic peaks and peak intensity ratio. Principal component analysis (PCA) was used for investigating the difference of various samples and reducing the dimensionality of the dataset. Performances of some classical classifiers were compared for bacterial detection and identification including decision tree (DT), artificial neural network (ANN), and Fisher's discriminant analysis (FDA). Correct recognition ratio (CRR), area under the receiver operating characteristic curve (ROC), cumulative gains, and lift charts were used to evaluate the performance of models. The impact of different pretreatment methods on the models was explored, and pretreatment methods include Savitzky-Golay algorithm smoothing (SG), standard normal variate (SNV), multivariate scatter correction (MSC), and Savitzky-Golay algorithm 1st Derivative (SG 1st Der). In the DT, ANN, and FDA model, FDA is more robust for overfitting problem and offers the highest accuracy. Most pretreatment methods raised the performance of the models except SNV. The results revealed that CRM coupled with chemometrics offers a powerful tool for the discrimination of foodborne pathogenic bacteria.
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Affiliation(s)
- Jin Zhang
- Criminal Investigation School, People’s Public Security University of China, Beijing, China
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Pengya Gao
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yuan Wu
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xiaomei Yan
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Changyun Ye
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Weili Liang
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Meiying Yan
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xuefang Xu
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Diseases Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Hong Jiang
- Criminal Investigation School, People’s Public Security University of China, Beijing, China
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Brunt J, van Vliet AHM, Carter AT, Stringer SC, Amar C, Grant KA, Godbole G, Peck MW. Diversity of the Genomes and Neurotoxins of Strains of Clostridium botulinum Group I and Clostridium sporogenes Associated with Foodborne, Infant and Wound Botulism. Toxins (Basel) 2020; 12:toxins12090586. [PMID: 32932818 PMCID: PMC7551954 DOI: 10.3390/toxins12090586] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 09/02/2020] [Accepted: 09/08/2020] [Indexed: 12/23/2022] Open
Abstract
Clostridium botulinum Group I and Clostridium sporogenes are closely related bacteria responsible for foodborne, infant and wound botulism. A comparative genomic study with 556 highly diverse strains of C. botulinum Group I and C. sporogenes (including 417 newly sequenced strains) has been carried out to characterise the genetic diversity and spread of these bacteria and their neurotoxin genes. Core genome single-nucleotide polymorphism (SNP) analysis revealed two major lineages; C. botulinum Group I (most strains possessed botulinum neurotoxin gene(s) of types A, B and/or F) and C. sporogenes (some strains possessed a type B botulinum neurotoxin gene). Both lineages contained strains responsible for foodborne, infant and wound botulism. A new C. sporogenes cluster was identified that included five strains with a gene encoding botulinum neurotoxin sub-type B1. There was significant evidence of horizontal transfer of botulinum neurotoxin genes between distantly related bacteria. Population structure/diversity have been characterised, and novel associations discovered between whole genome lineage, botulinum neurotoxin sub-type variant, epidemiological links to foodborne, infant and wound botulism, and geographic origin. The impact of genomic and physiological variability on the botulism risk has been assessed. The genome sequences are a valuable resource for future research (e.g., pathogen biology, evolution of C. botulinum and its neurotoxin genes, improved pathogen detection and discrimination), and support enhanced risk assessments and the prevention of botulism.
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Affiliation(s)
- Jason Brunt
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge CB3 0AS, UK
- Gut Health and Food Safety, Quadram Institute, Norwich Research Park, Norwich NR4 7UQ, UK; (A.T.C.); (S.C.S.)
- Correspondence: (J.B.); (M.W.P.)
| | - Arnoud H. M. van Vliet
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7AL, UK;
| | - Andrew T. Carter
- Gut Health and Food Safety, Quadram Institute, Norwich Research Park, Norwich NR4 7UQ, UK; (A.T.C.); (S.C.S.)
| | - Sandra C. Stringer
- Gut Health and Food Safety, Quadram Institute, Norwich Research Park, Norwich NR4 7UQ, UK; (A.T.C.); (S.C.S.)
| | - Corinne Amar
- Gastrointestinal Pathogens Unit, National Infection Service, Public Health England, London NW9 5EQ, UK; (C.A.); (K.A.G.); (G.G.)
| | - Kathie A. Grant
- Gastrointestinal Pathogens Unit, National Infection Service, Public Health England, London NW9 5EQ, UK; (C.A.); (K.A.G.); (G.G.)
| | - Gauri Godbole
- Gastrointestinal Pathogens Unit, National Infection Service, Public Health England, London NW9 5EQ, UK; (C.A.); (K.A.G.); (G.G.)
| | - Michael W. Peck
- Gut Health and Food Safety, Quadram Institute, Norwich Research Park, Norwich NR4 7UQ, UK; (A.T.C.); (S.C.S.)
- Correspondence: (J.B.); (M.W.P.)
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Abstract
C. botulinum Groups I and II form botulinum neurotoxin and cause foodborne botulism. Increased knowledge of C. botulinum Group I and II genomes and neurotoxin diversity. Impact on food safety via improved surveillance and tracing/tracking during outbreaks. New insights into C. botulinum biology, food chain transmission, evolution.
The deadly botulinum neurotoxin formed by Clostridium botulinum is the causative agent of foodborne botulism. The increasing availability of C. botulinum genome sequences is starting to allow the genomic diversity of C. botulinum Groups I and II and their neurotoxins to be characterised. This information will impact on microbiological food safety through improved surveillance and tracing/tracking during outbreaks, and a better characterisation of C. botulinum Groups I and II, including the risk presented, and new insights into their biology, food chain transmission, and evolution.
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Smith TJ, Hill KK, Raphael BH. Historical and current perspectives on Clostridium botulinum diversity. Res Microbiol 2015; 166:290-302. [PMID: 25312020 PMCID: PMC11302483 DOI: 10.1016/j.resmic.2014.09.007] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Revised: 09/24/2014] [Accepted: 09/24/2014] [Indexed: 11/19/2022]
Abstract
For nearly one hundred years, researchers have attempted to categorize botulinum neurotoxin-producing clostridia and the toxins that they produce according to biochemical characterizations, serological comparisons, and genetic analyses. Throughout this period the bacteria and their toxins have defied such attempts at categorization. Below is a description of both historic and current Clostridium botulinum strain and neurotoxin information that illustrates how each new finding has significantly added to the knowledge of the botulinum neurotoxin-containing clostridia and their diversity.
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Affiliation(s)
- Theresa J Smith
- Molecular and Translational Sciences, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA.
| | - Karen K Hill
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Brian H Raphael
- Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
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Kull S, Schulz KM, Strotmeier JWN, Kirchner S, Schreiber T, Bollenbach A, Dabrowski PW, Nitsche A, Kalb SR, Dorner MB, Barr JR, Rummel A, Dorner BG. Isolation and functional characterization of the novel Clostridium botulinum neurotoxin A8 subtype. PLoS One 2015; 10:e0116381. [PMID: 25658638 PMCID: PMC4320087 DOI: 10.1371/journal.pone.0116381] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/06/2014] [Indexed: 12/31/2022] Open
Abstract
Botulism is a severe neurological disease caused by the complex family of botulinum neurotoxins (BoNT). Based on the different serotypes known today, a classification of serotype variants termed subtypes has been proposed according to sequence diversity and immunological properties. However, the relevance of BoNT subtypes is currently not well understood. Here we describe the isolation of a novel Clostridium botulinum strain from a food-borne botulism outbreak near Chemnitz, Germany. Comparison of its botulinum neurotoxin gene sequence with published sequences identified it to be a novel subtype within the BoNT/A serotype designated BoNT/A8. The neurotoxin gene is located within an ha-orfX+ cluster and showed highest homology to BoNT/A1, A2, A5, and A6. Unexpectedly, we found an arginine insertion located in the HC domain of the heavy chain, which is unique compared to all other BoNT/A subtypes known so far. Functional characterization revealed that the binding characteristics to its main neuronal protein receptor SV2C seemed unaffected, whereas binding to membrane-incorporated gangliosides was reduced in comparison to BoNT/A1. Moreover, we found significantly lower enzymatic activity of the natural, full-length neurotoxin and the recombinant light chain of BoNT/A8 compared to BoNT/A1 in different endopeptidase assays. Both reduced ganglioside binding and enzymatic activity may contribute to the considerably lower biological activity of BoNT/A8 as measured in a mouse phrenic nerve hemidiaphragm assay. Despite its reduced activity the novel BoNT/A8 subtype caused severe botulism in a 63-year-old male. To our knowledge, this is the first description and a comprehensive characterization of a novel BoNT/A subtype which combines genetic information on the neurotoxin gene cluster with an in-depth functional analysis using different technical approaches. Our results show that subtyping of BoNT is highly relevant and that understanding of the detailed toxin function might pave the way for the development of novel therapeutics and tailor-made antitoxins.
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Affiliation(s)
- Skadi Kull
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch-Institut, Berlin, Germany
| | - K. Melanie Schulz
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch-Institut, Berlin, Germany
| | | | - Sebastian Kirchner
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch-Institut, Berlin, Germany
| | - Tanja Schreiber
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch-Institut, Berlin, Germany
| | | | - P. Wojtek Dabrowski
- Highly Pathogenic Viruses (ZBS1), Centre for Biological Threats and Special Pathogens, Robert Koch-Institut, Berlin, Germany
| | - Andreas Nitsche
- Highly Pathogenic Viruses (ZBS1), Centre for Biological Threats and Special Pathogens, Robert Koch-Institut, Berlin, Germany
| | - Suzanne R. Kalb
- Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, Atlanta, Georgia, United States of America
| | - Martin B. Dorner
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch-Institut, Berlin, Germany
| | - John R. Barr
- Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, Atlanta, Georgia, United States of America
| | - Andreas Rummel
- Institut für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Brigitte G. Dorner
- Biological Toxins (ZBS3), Centre for Biological Threats and Special Pathogens, Robert Koch-Institut, Berlin, Germany
- * E-mail:
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Marshall KM, Nowaczyk L, Raphael BH, Skinner GE, Rukma Reddy N. Identification and genetic characterization of Clostridium botulinum serotype A strains from commercially pasteurized carrot juice. Food Microbiol 2014; 44:149-55. [PMID: 25084657 PMCID: PMC11302426 DOI: 10.1016/j.fm.2014.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/23/2014] [Accepted: 05/23/2014] [Indexed: 12/29/2022]
Abstract
Clostridium botulinum is an important foodborne pathogen capable of forming heat resistant endospores and producing deadly botulinum neurotoxins (BoNTs). In 2006, C. botulinum was responsible for an international outbreak of botulism attributed to the consumption of commercially pasteurized carrot juice. The purpose of this study was to isolate and characterize strains of C. botulinum from the adulterated product. Carrot juice bottles retrieved from the manufacturing facility were analyzed for the presence of BoNT and BoNT-producing isolates using DIG-ELISA. Toxigenic isolates from the carrot juice were analyzed using pulsed-field gel electrophoresis (PFGE) and DNA microarray analysis to determine their genetic relatedness to the original outbreak strains CDC51348 and CDC51303. PFGE revealed that isolates CJ4-1 and CJ10-1 shared an identical pulsotype with strain CDC51303, whereas isolate CJ5-1 displayed a unique restriction banding pattern. DNA microarray analysis identified several phage related genes unique to strain CJ5-1, and Southern hybridization analysis of XhoI digested and nondigested DNA showed their chromosomal location, while a homolog to pCLI_A009 of plasmid pCLI of C. botulinum serotype Langeland F, was located on a small plasmid. The acquisition or loss of bacteriophages and other mobile genetic elements among C. botulinum strains has epidemiological and evolutionary implications.
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Affiliation(s)
- Kristin M Marshall
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, 6502 South Archer Road, Bedford Park, IL 60501, USA.
| | - Louis Nowaczyk
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, 6502 South Archer Road, Bedford Park, IL 60501, USA.
| | - Brian H Raphael
- Centers for Disease Control and Prevention, 1600 Clifton Road, NE, Atlanta, GA 30329, USA.
| | - Guy E Skinner
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, 6502 South Archer Road, Bedford Park, IL 60501, USA.
| | - N Rukma Reddy
- Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, 6502 South Archer Road, Bedford Park, IL 60501, USA.
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7
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Immunoprecipitation of native botulinum neurotoxin complexes from Clostridium botulinum subtype A strains. Appl Environ Microbiol 2014; 81:481-91. [PMID: 25362065 DOI: 10.1128/aem.02817-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Botulinum neurotoxins (BoNTs) naturally exist as components of protein complexes containing nontoxic proteins. The nontoxic proteins impart stability of BoNTs in the gastrointestinal tract and during purification and handling. The two primary neurotoxin complexes (TCs) are (i) TC1, consisting of BoNT, nontoxin-nonhemagglutinin (NTNH), and hemagglutinins (HAs), and (ii) TC2, consisting of BoNT and NTNH (and possibly OrfX proteins). In this study, BoNT/A subtypes A1, A2, A3, and A5 were examined for the compositions of their TCs in culture extracts using immunoprecipitation (IP). IP analyses showed that BoNT/A1 and BoNT/A5 form TC1s, while BoNT/A2 and BoNT/A3 form TC2s. A Clostridium botulinum host strain expressing recombinant BoNT/A4 (normally present as a TC2) from an extrachromosomal plasmid formed a TC1 with complexing proteins from the host strain, indicating that the HAs and NTNH encoded on the chromosome associated with the plasmid-encoded BoNT/A4. Strain NCTC 2916 (A1/silent B1), which carries both an ha silent bont/b cluster and an orfX bont/a1 cluster, was also examined. IP analysis revealed that NCTC 2916 formed only a TC2 containing BoNT/A1 and its associated NTNH. No association between BoNT/A1 and the nontoxic proteins from the silent bont/b cluster was detected, although the HAs were expressed as determined by Western blotting analysis. Additionally, NTNH and HAs from the silent bont/b cluster did not form a complex in NCTC 2916. The stabilities of the two types of TC differed at various pHs and with addition of KCl and NaCl. TC1 complexes were more stable than TC2 complexes. Mouse serum stabilized TC2, while TC1 was unaffected.
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Brunt J, Plowman J, Gaskin DJH, Itchner M, Carter AT, Peck MW. Functional characterisation of germinant receptors in Clostridium botulinum and Clostridium sporogenes presents novel insights into spore germination systems. PLoS Pathog 2014; 10:e1004382. [PMID: 25210747 PMCID: PMC4161481 DOI: 10.1371/journal.ppat.1004382] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 08/04/2014] [Indexed: 01/05/2023] Open
Abstract
Clostridium botulinum is a dangerous pathogen that forms the highly potent botulinum toxin, which when ingested causes a deadly neuroparalytic disease. The closely related Clostridium sporogenes is occasionally pathogenic, frequently associated with food spoilage and regarded as the non-toxigenic equivalent of Group I C. botulinum. Both species form highly resistant spores that are ubiquitous in the environment and which, under favourable growth conditions germinate to produce vegetative cells. To improve the control of botulinum neurotoxin-forming clostridia, it is imperative to comprehend the mechanisms by which spores germinate. Germination is initiated following the recognition of small molecules (germinants) by a specific germinant receptor (GR) located in the spore inner membrane. The present study precisely defines clostridial GRs, germinants and co-germinants. Group I C. botulinum ATCC3502 contains two tricistronic and one pentacistronic GR operons, while C. sporogenes ATCC15579 has three tricistronic and one tetracistronic GR operons. Insertional knockout mutants, allied with characterisation of recombinant GRs shows for the first time that amino acid stimulated germination in C. botulinum requires two tri-cistronic encoded GRs which act in synergy and cannot function individually. Spore germination in C. sporogenes requires one tri-cistronic GR. Two other GRs form part of a complex involved in controlling the rate of amino-acid stimulated germination. The suitability of using C. sporogenes as a substitute for C. botulinum in germination studies and food challenge tests is discussed. Clostridium botulinum is a dangerous pathogen that forms the deadly botulinum neurotoxin. Strains of C. botulinum are present in the environment as spores. Under suitable conditions, the dormancy of the bacterial spore is broken, and germination occurs. Germination is initiated following the recognition of small molecules by a specific germinant receptor (GR) located within spores. Currently, the identification and characterisation of these GRs remains unknown, but is critical if strategies are to be developed to either prevent spore germination altogether, or to germinate all the spores and then inactivate the emergent sensitive vegetative cells. The present study has characterised two functionally active GRs in C. botulinum which act in synergy and cannot function individually, and a related functionally active GR in C. sporogenes. These GRs respond to amino acids. Other GRs appear to form part of a complex involved in controlling the speed of germination, or are not functionally active. This study provides new insights into the mechanisms involved in germination and will allow us to develop new strategies to control this deadly pathogen.
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Affiliation(s)
- Jason Brunt
- Gut Health and Food Safety, Institute of Food Research (IFR), Norwich Research Park, Colney, Norwich, Norfolk, United Kingdom
- * E-mail:
| | - June Plowman
- Gut Health and Food Safety, Institute of Food Research (IFR), Norwich Research Park, Colney, Norwich, Norfolk, United Kingdom
| | - Duncan J. H. Gaskin
- Gut Health and Food Safety, Institute of Food Research (IFR), Norwich Research Park, Colney, Norwich, Norfolk, United Kingdom
| | - Manoa Itchner
- Gut Health and Food Safety, Institute of Food Research (IFR), Norwich Research Park, Colney, Norwich, Norfolk, United Kingdom
| | - Andrew T. Carter
- Gut Health and Food Safety, Institute of Food Research (IFR), Norwich Research Park, Colney, Norwich, Norfolk, United Kingdom
| | - Michael W. Peck
- Gut Health and Food Safety, Institute of Food Research (IFR), Norwich Research Park, Colney, Norwich, Norfolk, United Kingdom
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Raphael BH, Shirey TB, Lúquez C, Maslanka SE. Distinguishing highly-related outbreak-associated Clostridium botulinum type A(B) strains. BMC Microbiol 2014; 14:192. [PMID: 25031122 PMCID: PMC4112988 DOI: 10.1186/1471-2180-14-192] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 07/10/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the United States, most Clostridium botulinum type A strains isolated during laboratory investigations of human botulism demonstrate the presence of an expressed type A botulinum neurotoxin (BoNT/A) gene and an unexpressed BoNT/B gene. These strains are designated type A(B). The most common pulsed-field gel electrophoresis (PFGE) pattern in the C. botulinum PulseNet database is composed of A(B) strains. The purpose of this study was to evaluate the ability of genome sequencing and multi-loci variable number of tandem repeat analysis (MLVA) to differentiate such strains. RESULTS The genome sequences of type A(B) strains evaluated in this study are closely related and cluster together compared to other available C. botulinum Group I genomes. In silico multilocus sequence typing (MLST) analysis (7-loci) was unable to differentiate any of the type A(B) strains isolated from seven different outbreak investigations evaluated in this study. A 15-locus MLVA scheme demonstrated an improved ability to differentiate these strains, however, repeat unit variation among the strains was restricted to only two loci. Reference-free single nucleotide polymorphism (SNP) analysis demonstrated the ability to differentiate strains from all of the outbreaks examined and a non-outbreak associated strain. CONCLUSIONS This study confirms that type A(B) strains that share the same PFGE pattern also share closely-related genome sequences. The lack of a complete type A(B) strain representative genome sequence hinders the ability to assemble genomes by reference mapping and analysis of SNPs at pre-identified sites. However, compared to other methods evaluated in this study, a reference-free SNP analysis demonstrated optimal subtyping utility for type A(B) strains using de novo assembled genome sequences.
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Affiliation(s)
- Brian H Raphael
- Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
| | - Timothy B Shirey
- Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
| | - Carolina Lúquez
- Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
| | - Susan E Maslanka
- Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA
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Auricchio B, Anniballi F, Fiore A, Skiby JE, De Medici D. Evaluation of DNA extraction methods suitable for PCR-based detection and genotyping of Clostridium botulinum. Biosecur Bioterror 2014; 11 Suppl 1:S200-6. [PMID: 23971807 DOI: 10.1089/bsp.2012.0082] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Sufficient quality and quantity of extracted DNA is critical to detecting and performing genotyping of Clostridium botulinum by means of PCR-based methods. An ideal extraction method has to optimize DNA yield, minimize DNA degradation, allow multiple samples to be extracted, and be efficient in terms of cost, time, labor, and supplies. Eleven botulinum toxin-producing clostridia strains and 25 samples (10 food, 13 clinical, and 2 environmental samples) naturally contaminated with botulinum toxin-producing clostridia were used to compare 4 DNA extraction procedures: Chelex(®) 100 matrix, Phenol-Cloroform-Isoamyl alcohol, NucliSENS(®) magnetic extraction kit, and DNeasy(®) Blood & Tissue kit. Integrity, purity, and amount of amplifiable DNA were evaluated. The results show that the DNeasy(®) Blood & Tissue kit is the best extraction method evaluated because it provided the most pure, intact, and amplifiable DNA. However, Chelex(®) 100 matrix seems to be suitable for PCR-based methods intended for laboratory diagnosis of suspected outbreaks of botulism, because it is faster and cheaper compared to DNeasy(®) Blood & Tissue kit, and for samples in which the mean of Ct values obtained are statistically different (P>0.05) with respect to the best method, no lack of PCR amplification was shown. In addition, molecular methods for laboratory diagnosis currently are based on a microbial enrichment step prior to PCR, and so the differences in amplification seem to not influence the analytical results.
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Dabritz HA, Hill KK, Barash JR, Ticknor LO, Helma CH, Dover N, Payne JR, Arnon SS. Molecular epidemiology of infant botulism in California and elsewhere, 1976-2010. J Infect Dis 2014; 210:1711-22. [PMID: 24924163 DOI: 10.1093/infdis/jiu331] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Infant botulism (IB), first identified in California in 1976, results from Clostridium botulinum spores that germinate, multiply, and produce botulinum neurotoxin (BoNT) in the immature intestine. From 1976 to 2010 we created an archive of 1090 BoNT-producing isolates consisting of 1012 IB patient (10 outpatient, 985 hospitalized, 17 sudden death), 25 food, 18 dust/soils, and 35 other strains. METHODS The mouse neutralization assay determined isolate toxin type (56% BoNT/A, 32% BoNT/B). Amplified fragment-length polymorphism (AFLP) analysis of the isolates was combined with epidemiologic information. RESULTS The AFLP dendrogram, the largest to date, contained 154 clades; 52% of isolates clustered in just 2 clades, 1 BoNT/A (n=418) and 1 BoNT/B (n=145). These clades constituted an endemic C. botulinum population that produced the entire clinical spectrum of IB. Isolates from the patient's home environment (dust/soil, honey) usually located to the same AFLP clade as the patient's isolate, thereby identifying the likely source of infective spores. C. botulinum A(B) strains were identified in California for the first time. CONCLUSIONS Combining molecular methods and epidemiological data created an effective tool that yielded novel insights into the genetic diversity of C. botulinum and the clinical spectrum, occurrence, and distribution of IB in California.
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Affiliation(s)
- Haydee A Dabritz
- Infant Botulism Treatment and Prevention Program, Division of Communicable Disease Control, Center for Infectious Diseases, California Department of Public Health, Richmond
| | | | - Jason R Barash
- Infant Botulism Treatment and Prevention Program, Division of Communicable Disease Control, Center for Infectious Diseases, California Department of Public Health, Richmond
| | - Lawrence O Ticknor
- Computing, Computational and Statistical Sciences Division, Los Alamos National Laboratory, New Mexico
| | | | - Nir Dover
- Infant Botulism Treatment and Prevention Program, Division of Communicable Disease Control, Center for Infectious Diseases, California Department of Public Health, Richmond
| | - Jessica R Payne
- Infant Botulism Treatment and Prevention Program, Division of Communicable Disease Control, Center for Infectious Diseases, California Department of Public Health, Richmond
| | - Stephen S Arnon
- Infant Botulism Treatment and Prevention Program, Division of Communicable Disease Control, Center for Infectious Diseases, California Department of Public Health, Richmond
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12
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Abstract
Botulinum neurotoxin type F (BoNT/F) may be produced by Clostridium botulinum alone or in combination with another toxin type such as BoNT/A or BoNT/B. Type F neurotoxin gene sequences have been further classified into seven toxin subtypes. Recently, the genome sequence of one strain of C. botulinum (Af84) was shown to contain three neurotoxin genes (bont/F4, bont/F5, and bont/A2). In this study, eight strains containing bont/F4 and seven strains containing bont/F5 were examined. Culture supernatants produced by these strains were incubated with BoNT/F-specific peptide substrates. Cleavage products of these peptides were subjected to mass spectral analysis, allowing detection of the BoNT/F subtypes present in the culture supernatants. PCR analysis demonstrated that a plasmid-specific marker (PL-6) was observed only among strains containing bont/F5. Among these strains, Southern hybridization revealed the presence of an approximately 242-kb plasmid harboring bont/F5. Genome sequencing of four of these strains revealed that the genomic backgrounds of strains harboring either bont/F4 or bont/F5 are diverse. None of the strains analyzed in this study were shown to produce BoNT/F4 and BoNT/F5 simultaneously, suggesting that strain Af84 is unusual. Finally, these data support a role for the mobility of a bont/F5-carrying plasmid among strains of diverse genomic backgrounds.
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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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Raphael BH, Lautenschlager M, Kalb SR, de Jong LIT, Frace M, Lúquez C, Barr JR, Fernández RA, Maslanka SE. Analysis of a unique Clostridium botulinum strain from the Southern hemisphere producing a novel type E botulinum neurotoxin subtype. BMC Microbiol 2012; 12:245. [PMID: 23113872 PMCID: PMC3558463 DOI: 10.1186/1471-2180-12-245] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 10/30/2012] [Indexed: 01/01/2023] Open
Abstract
Background Clostridium botulinum strains that produce botulinum neurotoxin type E (BoNT/E) are most commonly isolated from botulism cases, marine environments, and animals in regions of high latitude in the Northern hemisphere. A strain of C. botulinum type E (CDC66177) was isolated from soil in Chubut, Argentina. Previous studies showed that the amino acid sequences of BoNT/E produced by various strains differ by < 6% and that the type E neurotoxin gene cluster inserts into the rarA operon. Results Genetic and mass spectral analysis demonstrated that the BoNT/E produced by CDC66177 is a novel toxin subtype (E9). Toxin gene sequencing indicated that BoNT/E9 differed by nearly 11% at the amino acid level compared to BoNT/E1. Mass spectrometric analysis of BoNT/E9 revealed that its endopeptidase substrate cleavage site was identical to other BoNT/E subtypes. Further analysis of this strain demonstrated that its 16S rRNA sequence clustered with other Group II C. botulinum (producing BoNT types B, E, and F) strains. Genomic DNA isolated from strain CDC66177 hybridized with fewer probes using a Group II C. botulinum subtyping microarray compared to other type E strains examined. Whole genome shotgun sequencing of strain CDC66177 revealed that while the toxin gene cluster inserted into the rarA operon similar to other type E strains, its overall genome content shared greater similarity with a Group II C. botulinum type B strain (17B). Conclusions These results expand our understanding of the global distribution of C. botulinum type E strains and suggest that the type E toxin gene cluster may be able to insert into C. botulinum strains with a more diverse genetic background than previously recognized.
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Affiliation(s)
- Brian H Raphael
- Centers for Disease Control and Prevention, Atlanta, GA 30329, USA.
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15
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Singh AK, Stanker LH, Sharma SK. Botulinum neurotoxin: where are we with detection technologies? Crit Rev Microbiol 2012; 39:43-56. [PMID: 22676403 DOI: 10.3109/1040841x.2012.691457] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Because of its high toxicity, botulinum neurotoxin (BoNT) poses a significant risk to humans and it represents a possible biological warfare agent. Nevertheless, BoNT serotypes A and B are considered an effective treatment for a variety of neurological disorders. The growing applicability of BoNT as a drug, and its potential use as a biological threat agent, highlight the urgent need to develop sensitive detection assays and therapeutic counter measures. In the last decade, significant progress has been made in BoNT detection technologies but none have fully replaced the mouse lethality assay, the current "gold standard". Recently, new advances in robotics and the availability of new reagents have allowed development of methods for rapid toxin analysis. These technologies while promising need further refinement.
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Affiliation(s)
- Ajay K Singh
- Food and Drug Administration, Center for Food Safety and Applied Nutrition, College Park, MD 20740, USA
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De novo subtype and strain identification of botulinum neurotoxin type B through toxin proteomics. Anal Bioanal Chem 2012; 403:215-26. [PMID: 22395449 PMCID: PMC3309144 DOI: 10.1007/s00216-012-5767-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 01/05/2012] [Accepted: 01/18/2012] [Indexed: 02/06/2023]
Abstract
Botulinum neurotoxins (BoNTs) cause the disease botulism, which can be lethal if untreated. There are seven known serotypes of BoNT, A–G, defined by their response to antisera. Many serotypes are distinguished into differing subtypes based on amino acid sequence, and many subtypes are further differentiated into toxin variants. Previous work in our laboratory described the use of a proteomics approach to distinguish subtype BoNT/A1 from BoNT/A2 where BoNT identities were confirmed after searching data against a database containing protein sequences of all known BoNT/A subtypes. We now describe here a similar approach to differentiate subtypes BoNT/B1, /B2, /B3, /B4, and /B5. Additionally, to identify new subtypes or hitherto unpublished amino acid substitutions, we created an amino acid substitution database covering every possible amino acid change. We used this database to differentiate multiple toxin variants within subtypes of BoNT/B1 and B2. More importantly, with our amino acid substitution database, we were able to identify a novel BoNT/B subtype, designated here as BoNT/B7. These techniques allow for subtype and strain level identification of both known and unknown BoNT/B rapidly with no DNA required. Identification of an existing or new BoNT/B can be accomplished through MS/MS analysis of digestion fragments of the protein. ![]()
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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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