- Clostridial spores are widely distributed in the environment
- May enter traumatic or surgical wounds
- Contamination may also occur from patients own faecal flora
Microbiology
- Gas gangrene results from the following clostridial species:
- Clostridium welchii
- Clostridium oedmatiens
- Clostridium septicum
- Microscopy of wound exudate shows gram-positive bacilli
- Rectangular shape without spore formation
- Anaerobic culture on blood agar show haemolytic colonies (Clostridium welchii)
- 'Stormy' clot reaction with litmus milk
- Clostridium welchii also shows positive Nagler reaction
- Due to lecithinase reaction of alpha exotoxin
Clinical features
- Patients are generally toxic and unwell
- Often have features of shock, jaundice, haemolysis or acute renal failure
- Local signs of gas gangrene include:
- Myositis or myonecrosis
- Gas formation with palpable crepitus
- Mottled discolouration of the overlying skin
- Plain X-ray often shows gas in the subcutaneous tissue and fascial plains
Treatment
- Failure of recognition often results in rapid deterioration
- Patients require adequate resuscitation
- Debridement or amputation should be considered to remove affected tissue or limb
- Organisms are usually sensitive to penicillin
- Hyperbaric oxygen may be helpful
Prevention
- Benzylpenicillin antibiotic prophylaxis in those with
- Contaminated wounds
- Diabetic undergoing elective peripheral vascular surgery
Bibliography
Chapnick E L, Abtar E L. Necrotising
soft tissue infection. Infect Dis Clin North Am 1996;
10: 835-855.
Nicolls R L, Smith J W. Anaerobes
from a surgical perspective. Clin Infect Dis 1994;
18 (Suppl 4): S280-S286.
Urschel J D. Necrotising soft tissue infections.
Postgrad Med J 1999; 75:
645-649. |