Clostridium perfringens – An Overview

Clostridium perfringens is an anaerobic, Gram positive, spore forming, non-motile and rod shaped organism belong to genus Clostridium. Previously, this organism was known as Clostridium welchii or Bacillus welchii. C. perfringens has cosmopolitan nature and found everywhere in soil and water etc. C. perfringens is also normal inhabitant of gastrointestinal tract in humans and animals and is ranked 3rd among food poisoning causing pathogens in the world.

  1. perfringens genomic structure is mainly made up of a single circular chromosome which contains approximately 3.6 billion base pairs and GC contents are ranged between 25-56% indicating that this organism has less GC contents compared to other G +ve bacteria. C. perfringens chromosome encloses various rRNA and tRNA genes that encode different transporters to transport different substances like amino acids, carbohydrates and nucleotides. Similar to other organisms like Mycoplasma and B. subtilis, this organism arranges its genes in such way that its replication and transcriptional processes have similar direction.
  2. perfringens is a Gram-positive bacterium contains thick cell wall of peptidoglycans. As an anaerobic organism, C. perfringens obtains its energy through anaerobic respiration by utilizing nitrate as electron acceptor because this molecule allows increased number of phosphorylation reactions at substrate level and produce more energy. C. perfringens produces gas like CO2 through anaerobic fermentation process which makes more anaerobic environment in the host tissue. C. perfringens genome contains different glycolytic enzyme genes and these enzymes cause break down of complex sugar compounds into their simpler forms. C. perfringens genome lacks most genes essential for biosynthesis of amino acids which results in poor growth on essential amino acid deficient media.
  3. perfringens is mainly categorized into different 5 toxinotypes (A-E) on the basis of presence of different exotoxins like alpha, beta, beta-2, epsilon, iota and enterotoxin. This organism is mostly responsible for food poisoning cases and C. perfringens enterotoxin (CPE) is a main virulent factor for most gastrointestinal diseases in humans and animals. When C. perfringens contaminated food come in contact with humans and animals, CPE initiates its membrane action. Firstly, CPE bind specifically with receptors present on the surface of plasma membrane and form complexes. These small complexes attach to other membrane proteins and form large complexes and effect the permeability of membrane. These complexes are lethal because now cells will not able to maintain their osmotic equilibrium due to loss of permeability of membrane.
  4. perfringens has optimum growth at 370C temperature and temperature ranges between 37-470C under anaerobic conditions. C. perfringens has generation time less than 7 minutes. This organism has pH range of 6-7 for speedy growth. C. perfringens vegetative cells are killed by heating but can survive under refrigeration and freezing temperatures. However, spores are highly resistant to heat and survive for hours.
  5. perfringens is also responsible for various infections along with food poisoning like gas gangrene, tissue necrosis and emphysematous swellings due to gas and toxins production. In animals, C. perfringens type B, C and E cause enteritis and enterocolitis in foals, lambs and calves. C. perfringens type A produces Necrotic Enteritis in poultry while C. perfringens type D is mainly responsible for Pulpy Kidney Disease or Enterotoxaemia in sheep, goats and other animals.

Diagnosis of C. perfringens from suspected samples can be made by different methods. These methods include culturing, staining, biochemical tests, ELISA, serotyping and different PCR techniques like Ribotyping, Multiple locus variable number tandem repeat analysis (MLVNTRs), Pulsed field gel electrophoresis (PFGE), Restriction fragment length polymorphism (RFLP) and Amplified fragment length polymorphism (AFLP) etc. On specific media like Egg yolk agar, C. perfringens produces lecithinase activity due to opalescent growth. In blood agar, C. perfringens shows beta hemolysis. Gram’s staining indicates that C. perfringens is a G +ve organism with thick outer layer of peptidoglycan in its cell wall. Different biochemical tests like Catalase, Indole, Litmus milk and Lipase activities etc are used for further confirmation.

The growth of C. perfringens can be controlled and prevented by proper cooking of food items at specified temperature, good sanitation conditions, proper storage facilities and refrigeration. In infected cases, administration of antibiotics like Neomycin, Penicillin and Ampicillin etc are used for treatment. Sometimes in severe cases, amputation of the effected tissue or area is only a viable option for survival.

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