Reclassification of Eubacterium combesii and discrepancies in the nomenclature of botulinum neurotoxin-producing clostridia: Challenging Opinion 69. Request for an Opinion

Dobritsa, Anatoly P.; Kutumbaka, Kirthi K.; Samadpour, Mansour

doi:10.1099/ijsem.0.002942

Cited by 12 publications

(13 citation statements)

References 31 publications

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“…C. botulinum Group I is one of four distinct groups within the species C. botulinum , a polyphyletic taxon united only by the ability to form the highly potent botulinum neurotoxin [ 1 , 2 , 3 , 4 , 5 ]. C. sporogenes has often been perceived as a non-toxic close relative of C. botulinum Group I [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. It is an important cause of food spoilage [ 14 , 15 , 16 ], and used as a surrogate for C. botulinum Group I in food sterilisation tests [ 7 , 14 , 15 , 17 , 18 , 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

“…It is an important cause of food spoilage [ 14 , 15 , 16 ], and used as a surrogate for C. botulinum Group I in food sterilisation tests [ 7 , 14 , 15 , 17 , 18 , 19 , 20 ]. Recent findings, however, show that C. sporogenes is not merely a non-toxic form of C. botulinum Group I [ 8 , 10 , 21 , 22 , 23 , 24 , 25 ]. Genetic analysis has revealed that both C. botulinum Group I and C. sporogenes contain strains that either form or do not form botulinum neurotoxin.…”

Section: Introductionmentioning

confidence: 99%

“…Genetic analysis has revealed that both C. botulinum Group I and C. sporogenes contain strains that either form or do not form botulinum neurotoxin. Most strains of C. botulinum Group I (but not all) form botulinum neurotoxin, whilst some (but not most) C. sporogenes strains also form botulinum neurotoxin [ 8 , 10 , 22 , 24 , 25 ]. If C. botulinum Group I and C. sporogenes are considered separate species, then C. sporogenes represents another distinct bacterium that forms botulinum neurotoxin [ 22 , 24 , 25 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

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Diversity of the Genomes and Neurotoxins of Strains of Clostridium botulinum Group I and Clostridium sporogenes Associated with Foodborne, Infant and Wound Botulism

Brunt

Vliet

Carter

et al. 2020

Toxins

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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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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Diversity of the Genomes and Neurotoxins of Strains of Clostridium botulinum Group I and Clostridium sporogenes Associated with Foodborne, Infant and Wound Botulism

Brunt

Vliet

Carter

et al. 2020

Toxins

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“…Consistent with prior studies, several non-toxic strains loaded within the G1 C. botulinum clade, including C. sporogenes str. PA 3679, C. combesii , and G1 C. botulinum strains SU1575NT and SU1033 ( Figure 2A ; Butler et al, 2017 ; Dobritsa et al, 2018 ; Brunt et al, 2020a ). Conversely, seven strains previously described and deposited as C. botulinum loaded into the C. sporogenes clade, four of which possessed no detected bont gene cluster ( Figure 2A and Supplementary File 1 ).…”

Section: Resultsmentioning

confidence: 99%

Endogenous CRISPR-Cas Systems in Group I Clostridium botulinum and Clostridium sporogenes Do Not Directly Target the Botulinum Neurotoxin Gene Cluster

et al. 2022

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Most strains of proteolytic group I Clostridium botulinum (G1 C. botulinum) and some strains of Clostridium sporogenes possess genes encoding botulinum neurotoxin (BoNT), a potent neuroparalytic agent. Within G1 C. botulinum, conserved bont gene clusters of three major toxin serotypes (bont/A/B/F) can be found on conjugative plasmids and/or within chromosomal pathogenicity islands. CRISPR-Cas systems enable site-specific targeting of previously encountered mobile genetic elements (MGE) such as plasmids and bacteriophage through the creation of a spacer library complementary to protospacers within the MGEs. To examine whether endogenous CRISPR-Cas systems restrict the transfer of bont gene clusters across strains we conducted a bioinformatic analysis profiling endogenous CRISPR-Cas systems from 241 G1 C. botulinum and C. sporogenes strains. Approximately 6,200 CRISPR spacers were identified across the strains and Type I-B, III-A/B/D cas genes and CRISPR array features were identified in 83% of the strains. Mapping the predicted spacers against the masked strain and RefSeq plasmid dataset identified 56,000 spacer–protospacer matches. While spacers mapped heavily to targets within bont(+) plasmids, no protospacers were identified within the bont gene clusters. These results indicate the toxin is not a direct target of CRISPR-Cas but the plasmids predominantly responsible for its mobilization are. Finally, while the presence of a CRISPR-Cas system did not reliably indicate the presence or absence of a bont gene cluster, comparative genomics across strains indicates they often occupy the same hypervariable loci common to both species, potentially suggesting similar mechanisms are involved in the acquisition and curation of both genomic features.

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“…C. botulinum group I usually harbor botulinum neurotoxin (bont) genes on their chromosomes, while some carry these genes on large plasmids. Recent findings, however, show that C. sporogenes is not a nontoxic form of C. botulinum Group I [62,63]. Most strains of C. botulinum Group I form botulinum neurotoxin, whilst some C. sporogenes strains also form botulinum neurotoxin [59].…”

Section: Discussionmentioning

confidence: 98%

Clostridia in Insect Processed Animal Proteins—Is an Epidemiological Problem Possible?

et al. 2021

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The aim of this study was the evaluation of the insect processed animal protein (IPAP) contamination level by Clostridium spp. Particularly, we screened for the occurrence of pathogenic species of Clostridia. The samples of IPAP were derived from yellow mealworm (Tenebrio molitor) and black soldier fly (Hermetia illucens) available in the Polish market. The IPAPs were added to experimental feeds for poultry. The differences between the contamination levels of the control (without the addition of IPAP) and experimental (with the addition of IPAP) groups were monitored. The samples were also examined by culture and PCR-based methods to detect 16S rDNA and genes determining botulinum toxin (BoNT) production. Statistical significance was noticed among the feed with the IPAP addition, as well as an increase of contamination by Clostridium spp. In one sample of IPAP, the occurrence of ntnh and bont/D genes determining the production of BoNT/D was noticed. However, a positive result was noticed only at the step of the liquid culture; the Clostridium botulinum type D strain was not isolated. Phenotypically, and according to the 16S rDNA analysis, genetically similar strains to C. botulinum species were isolated. Considering the microbiological safety of IPAP and expanding possibility of its use in livestock animal feed, it seems to be reasonable to provide complex risk assessment on the potential transfer of Clostridia into feed compounds, to assure the safety and sustainable development of insect PAP industry.

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Reclassification of Eubacterium combesii and discrepancies in the nomenclature of botulinum neurotoxin-producing clostridia: Challenging Opinion 69. Request for an Opinion

Cited by 12 publications

References 31 publications

Diversity of the Genomes and Neurotoxins of Strains of Clostridium botulinum Group I and Clostridium sporogenes Associated with Foodborne, Infant and Wound Botulism

Diversity of the Genomes and Neurotoxins of Strains of Clostridium botulinum Group I and Clostridium sporogenes Associated with Foodborne, Infant and Wound Botulism

Endogenous CRISPR-Cas Systems in Group I Clostridium botulinum and Clostridium sporogenes Do Not Directly Target the Botulinum Neurotoxin Gene Cluster

Clostridia in Insect Processed Animal Proteins—Is an Epidemiological Problem Possible?

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