Systematic Veterinary Bacteriology and Mycology

FAMILY CHARACTERS

Classification

• They are pleomorphic, rod shaped; long filaments and involution forms are common.
• Spore formation occurs with varying frequency in different species.
• The shape and position of the spores vary in different species.
• The clostridia are motile with peritrichous flagella except C.welchii and C.tetani typeVI. C.welchii is capsulated, while others are not.
• Clostridia are anaerobic. C.odematiens are strict anaerobes and die on exposure to oxygen.
• C.histolyticum and C.welchii are aerotolerent and may even grow aerobically.
• The clostridia are fermentative, oxidase negative and catalase negative organisms.
• A very useful media for isolation of clostridia is Robertson’s cooked meat broth.
• Clostridia grow in the medium, rendering the broth turbid most species produces gas.
• Saccharolytic species turn the meat pink – C.odematiens, C.septicum, C.chauvoei and C.welchii.
• Proteolytic species turn the meat black and produce foul and pervasive odour - C.tetani, C. botulinum, C.haemolyticum.
  In litmus milk medium, the production of acid, clot and gas can be detected