MORPHOLOGY OF CLOSTRIDIUM PERFRINGENS (CLOSTRIDIUM WELCHII)
Shape – Clostridium perfringens is a large, rod shape (bacillus) bacterium with straight, parallel sides and rounded or truncated ends.
Size – The size of Clostridium perfringens is about 4–6 µm × 1 µm (micrometer).
Arrangement Of Cells – Clostridium perfringens is arranged singly, in short chains or in small bundles. They are pleomorphic, filamentous & involution forms are commonly present.
Motility – Clostridium perfringens is a Non-motile bacterium.
Flagella – Clostridium perfringens is a Non-flagellated bacterium
Spores – The Central or Sub-terminal spores are present in C. perfringens but are rarely seen in artificial cultures or in the microscopic examination of lesions. The spore formation takes place on a selective medium used for the cultivations of this bacterium.
Capsule – C. perfringens is a capsulated bacterium. The capsule can easily be demonstrated using India ink preparation, appear as a clear halo in a dark background.
Gram Staining Reaction – Clostridium perfringens is a Gram +ve (Positive) bacterium.
CULTURE REQUIREMENTS OF CLOSTRIDIUM PERFRINGENS (CLOSTRIDIUM WELCHII)
⇒ Special requirements – Clostridium perfringens or C. welchii have complex nutritional requirements and readily grow in a media containing Blood or Egg, commonly Blood Agar medium & Robertson’s Cooked meat broth medium is used for the cultivation of Clostridium perfringens in Laboratory.
⇒ Optimum temperature – Clostridium perfringens ranges from 20 –50°C but usually grown at 37°C in laboratories. Also, 45°C is the optimum temperature for some strains of the Clostridium perfringens.
⇒ Optimum pH – 5.5 – 8.0
⇒ Oxygen requirements – C. perfringens (C. welchii) is an anaerobic bacterium i.e. can grow in the absence of oxygen and it is also a microaerophilic organism i.e. can grow in the low oxygen environment.
⇒ There are various culture media used for the cultivation of C. perfringens (C. welchii) in the laboratory and most commonly the Blood Agar medium and CMB medium is used, the other media are as follows –
- Egg yolk Agar medium
- Columbia Horse Blood Agar medium
- MacConkey Agar medium
- Litmus milk
- Tryptose Sulfite Cycloserine (TSC) Agar (Selective medium).
- Tryptone Sulfite Neomycin (TSN) Agar medium a.k.a. Marshal’s medium (Selective medium).
- The liquid medium (Nutrient Broth medium, TSB medium, etc.).
⇒ The Tryptose sulfite Cycloserine Agar (TSC) medium which is the Selective medium for Clostridium perfringens can be prepared by incorporating Cycloserine alone or along with the 4-Methylumbelliferyl-phosphate disodium salt in Perfringens Agar base or in TSC Agar base medium for the growth of Clostridium perfringens.
⇒ Similarly, the Tryptone Sulfite Neomycin Agar (TSN) medium which is also a selective medium for Clostridium perfringens can be prepared by incorporating Neomycin and Polymixin B Sulfate in the TSN Agar Base medium for the Growth of Clostridium perfringens.
⇒ The Litmus milk for the Litmus milk test which is commonly used for the C. perfringens can easily be prepared in the laboratory by suspending Skim milk powder (100gm), Litmus powder (0.5 gm) & Sodium sulfite (0.5gm) in 1000 ml of distilled water.
CULTURE CHARACTERISTICS OF CLOSTRIDIUM PERFRINGENS (CLOSTRIDIUM WELCHII)
Cultural Characteristics Blood Agar Medium (BAM) Tryptose Sulfite Cycloserine (TSC) Agar medium Tryptone Sulfite Neomycin (TSN) Agar medium
Hemolysis Target Hemolysis ----- -----
Shape Circular or Round Circular or Round Circular or Round
Size 3-5 mm 2-3 mm 2-3 mm
Elevation No elevation - Flat Colonies ----- -----
Surface Flat & Filamentous Flat Smooth
Color White or light yellow Black Black
Structure Translucent –Opaque Translucent –Opaque Opaque
In Roberson’s Cooked meat broth medium, C. perfringens grows well and the meat is turned pink or Black as per the type of strain. The Saccharolytic strains of C. perfringens turn the meat pink with sour odor and the Acidic reaction of the medium whereas the Proteolytic species of Clostridium perfringens turns the meat black with the foul smell and Acidic pH of the medium.
In litmus milk test, the fermentation of lactose (sugar present in milk) leads to the formation of acid in the medium, which is visible by the change in color of medium from blue to red and the clotted milk, due to the formation of acid which coagulates the casein (protein present in milk), usually marked by stormy fermentation (the clotted milk disrupted due to the gas produced during fermentation and the pressure of gas pushes it towards the mouth of test tube due to which the casein sticks to the wall of the tubes).
In liquid culture media like Trypticase soy broth or Nutrient broth, the growth of the bacterium occurs as a turbidity in the broth medium, but the growth is scanty in these ordinary media, which is further analyzed for the morphology (under the microscope), gram reaction, biochemical tests, and Clostridium perfringens specific tests.
THAT’S ALL ABOUT THE MORPHOLOGY AND CULTURE CHARACTERISTICS OF CLOSTRIDIUM PERFRINGENS (C. WELCHII OR BACILLUS WELCHII)
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