Characteristics of Clostridia :Positive - Spore - Endotoxic - Anaerobic - Saphrophtyic
- Gram positive
- Spore forming
- Subterminal
- Drumstick
- Exotoxin producing
- Botulinum - causes spastic paralysis with release of botulinum toxin (inhibits acetylcholine release) opisthotonus + involvement of respiratory muscles
- Perfringens (welchii) - proteolytic enzyme lecithinase causes gas production - gas gangrene (with characteristic smell)
- Tetani - produces tetanospasmin (inhibits inhibitory processes of motor neurones) causing muscular spasm and paralysis; prevented by tetanus toxoid immunisation / human anti-tetanus immunoglobulin
- Difficile - exotoxin produces cell membrane damage to epithelial cells leading to pseudomembranous colitis
- Anaerobic
- Oxygen forms free radicals
- Cells have little/no defence
- Saphrophytes - requires soil to protect them from dehydration