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===Overview===
*Organisms present in the soil, alimentary tract and faeces
*Endospores may be present in liver and may be reactivated to cause disease
*Neurotoxic clostridia, ''Clostridium tetani'' and ''Clostridium botulinum'' affect neuromuscular function but cause no tissue damage
*Histotoxic clostridia cause localised lesions in tissues and may cause toxaemia
*''C. perfringens'' cause inflammatory lesions in the gastrointestinal tract and enterotoxaemias in sheep
===Characteristics===
*Large Gram-positive rods
*Obligate anaerobes
*Fermentative, catalase negative, oxidase negative
*Straight or slightly curved
*Motile by flagellae
*Require enriched media for growth
*Produce endospores which vary in shape and location and cause bulging of mother cell
===Pathogenesis and pathogenicity===
*Produce extracellular digestive enzymes and toxic substance known as exotoxins
*Exotoxins cause necrosis, haemolysis and death
*Collagenase, hyaluronidase and DNase enymes facilitate spread through tissues
===Diagnosis===
*Anaerobic transport medium
*Culture on blood agar enriched with yeast extract, vitamin K and haemin
*Anaerobic culture with hydrogen supplement and 5-10% carbon dioxide for 48 hours
*Colonies of ''C. perfringens'' are 5mm diameter, circular, flat and grey and surrounded by a zone of double haemolysis
*Positive cAMP test with ''Streptococci agalactiae''
*Biochemical tests
*Toxins identified in body fluids by toxin neutralisation or protection tests in lab animals
*Nagler reaction to detect alpha toxin - plate neutralisation test
*Fluorescent antibody tests for histotoxic clostridia
*ELISA, PCR for toxin detection
*Sudden death in unvaccinated farm animals may suggest ''C. perfringens'' types B, C and D
*Post mortem
*Gram positive rods present on intestinal smears suggests clostridial enterotoxaemia
[[Category:Clostridium_species]]
[[Category:Clostridium_species]]