Related Experiment Video
Updated: May 11, 2026
08:00
Enrichment and Detection of Clostridium perfringens Toxinotypes in Retail Food Samples
Published on: October 18, 2019
Toxin plasmids of Clostridium perfringens
Jihong Li1, Vicki Adams, Trudi L Bannam
1Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Microbiology and Molecular Biology Reviews : MMBR
|May 24, 2013
Summary
Clostridium perfringens virulence relies on toxin production, often encoded on conjugative plasmids. These plasmids facilitate toxin gene transfer, enhancing bacterial adaptability and disease potential in the gastrointestinal tract.
Area of Science:
- Microbiology
- Genetics
- Infectious Diseases
Background:
- Clostridium perfringens causes histotoxic infections and gastrointestinal diseases in humans and animals.
- Bacterial virulence is linked to toxin production, with many toxins encoded on large plasmids.
- These toxin plasmids are often associated with mobile genetic elements.
Purpose of the Study:
- To investigate the role of toxin-encoding plasmids in Clostridium perfringens virulence.
- To understand the evolutionary origins and transfer mechanisms of toxin plasmids.
- To explore how plasmid-borne toxin genes contribute to bacterial adaptability in the gut.
Main Methods:
- Analysis of plasmid sizes and toxin gene content.
- Investigation of the association between toxin plasmids and mobile elements.
- Examination of the conjugation locus (tcp) and its role in plasmid transfer.
- Molecular Koch's postulates to confirm toxin importance.
Main Results:
- C. perfringens produces numerous toxins encoded on plasmids (45-140 kb).
- Toxin genes are frequently linked to mobile elements and can be mobilized.
- A common evolutionary origin is suggested for many toxin plasmids.
- The tcp locus mediates efficient conjugative transfer of toxin and resistance plasmids.
- Transfer to intestinal flora can amplify and prolong infections.
Conclusions:
- Conjugative toxin plasmids provide Clostridium perfringens with significant virulence plasticity.
- The association of toxin genes with conjugative plasmids and mobile elements enhances adaptability.
- This adaptability is crucial for C. perfringens in causing gastrointestinal diseases.
More Related Videos
Related Concept Videos
01:12Bacterial Toxins
Bacterial toxins are sophisticated virulence factors that enable pathogenic bacteria to interact with, invade, and damage host tissues. These toxins fall broadly into two types: protein exotoxins, which are secreted into the environment and target specific host receptors, and lipopolysaccharide endotoxins, which are structural components of the bacterial outer membrane released primarily during bacterial lysis or membrane shedding. Exotoxins generally act more selectively, binding to cell...
01:28Plasmids
Plasmids are extrachromosomal DNA molecules found in bacteria, archaea, and some eukaryotic microbes like yeast. These small, circular DNA structures typically contain fewer than 30 genes, although some may exist linearly. Plasmids vary in their number within a cell, known as copy number. Single-copy plasmids are present in one copy per cell and multi-copy plasmids are present in multiple copies, reaching over 100 copies per cell.Plasmids usually replicate independently of the chromosomal DNA...
01:18Bacterial Gastroenteritis
Bacterial gastroenteritis, characterized by diarrhea, abdominal cramps, and vomiting, is often caused by ingestion of contaminated food or water and is frequently associated with pathogenic Escherichia coli strains. These microbes exploit two principal mechanisms to inflict disease.Shiga toxin–producing E. coli, also referred to as STEC—notably O157:H7—release Shiga toxins that target ribosomes, blocking protein synthesis. The B subunit of the toxin binds the host glycolipid receptor...
01:26Bacterial Phylum Planctomycetes
Planctomycetes are a group of morphologically distinct bacteria predominantly classified into two orders: Planctomycetales and Brocadiales. These gram-negative bacteria exhibit unique features, including division by budding and the presence of stalks or appendages. Their cells are often found in rosette arrangements, and they are notable for possessing an S-layer in their cell envelope, which is relatively uncommon among bacteria. Additionally, Planctomycetes frequently exhibit intracellular...
01:20Endospores and Sporulation
Endospores are specialized, dormant cells primarily formed by Gram-positive bacteria, including Bacillus and Clostridium, enabling survival under extreme environmental conditions. Due to their unique composition and formation process, these structures are highly resistant to physical and chemical insults, such as extreme heat, ultraviolet and ionizing radiation, desiccation, and toxic chemicals. Rare instances of endospore-like structures have also been observed in some Gram-negative bacteria,...
01:28Diphtheria
Diphtheria is an acute, toxin-mediated infectious disease that primarily affects the upper respiratory tract. It is caused by Corynebacterium diphtheriae, a Gram-positive, pleomorphic rod that lacks spore-forming capability and exhibits a characteristic club-shaped morphology under microscopic examination. While C. diphtheriae can asymptomatically colonize mucosal surfaces, clinical disease manifests only when the bacterial strain is lysogenized by a specific β-corynephage. This phage...