Clostridium Flashcards
Laboratory characteristics of Clostridium?
Gram positive
Spore-forming
Anaerobic
Grow on blood agar
Where are clostridial species normally found?
Soil
GIT
female genital tract
Name four Clostridium species and what they cause.
C.difficile - pseudomembranous colitis
C. botulinum - botulism
C. tetani - tetanus
C. perfringens - gas gangrene + food poisoning
How does one normally acquire C.botulinum?
Breakdown in sterility during canning or bottling.
How does C.botulinum cause disease?
Produces botulinum toxin.
What does botulism toxin do to the body? Comment on its passage through the stomach.
Is the most potent neurotoxin.
Prevents release of acetylcholine at peripheral cholinergic synapses > muscle paralysis
*is not destroyed by digestive enzymes, destroyed by heat
What are signs of cholinergic blockade?
Dry mouth
Ileus (type of non-mechanical bowel obstruction)
Urinary retention
How much time elapses before symptoms become apparent with regards to C.botulinum?
12-36 hours (sometimes days)
Clinical manifestations of C.botulinum?
Weakness
dizziness
Diplopia (double vision) or blurred vision
Peripheral muscle weakness + respiratory paralysis
Fixed dilated pupils
Lassitude
Bulbar involvement - dysphagia, difficulty with speech
What is lassitude?
State of mental/physical weakness
*lack of energy
Does infection with C.botulinum result in fever?
No.
How can one diagnose C.botulinum infection?
Via clinical grounds
Demonstrate organism in blood
Isolate organism from gut
How to treat C.botulinum infection?
Mainly supportive.
Polyvalent antitoxin available (efficacy variable)
Penicillin (value uncertain)
What does C.perfringens produce and what does it do?
Lecithinase > causes gas gangrene
How can C.perfringens cause food poisoning?
Can produce an enterotoxin.
What clinical manifestations of C.perfringens are there?
Simple contamination Soft tissue infections Anaerobic cellulitis Gas gangrene Uterine gas gangrene Bacteriaemia
What does one mean by simple contamination with regards to C.perfringens?
That it’s isolation from a would does no necessarily mean infection as this bacterium is often found on the skin.
What is an example of a soft tissue infection involving C.perfringens?
Intra-abdominal infections < perforation
What is anaerobic cellulitis?
Diffuse spreading of cellulitis and fasciitis.
Signs of anaerobic fasciitis?
Toxaemia
Diffuse subcutaneous crepitus
Death > shock! renal failure, intravascular haemolysis
What tissue is involved in gas gangrene?
Muscle tissue.
What are bullae?
Fluid filled sacs/lesions that appear when fluid is trapped underneath a thin layer of skin
Signs of gas gangrene?
Bullae Pain Crepitus Renal failure Tachycardia Fever
How can someone develop uterine has gangrene?
Septic abortion
Even normal delivery
What tissue are involved in uterine gas gangrene?
Decidual (endometrium during pregnancy)
May involve uterus itself > mayo necrosis
How does one diagnose a C.perfringens infection?
Biopsy > bullae fluid or necrotic tissue
Culture > Lecithinase production + grow in anaerobic conditions
Treatment of C.perfringens infection?
Remove necrotic tissue
Antibiotics
Antitoxin?
Hyperbolic oxygen?
Which antibiotics are used to treat C.perfringens?
Metronidazole
Penicillin
Where is C.difficile normally found?
GIT
How is C.diffcile spread?
Via hands therefore infection control in hospital very important.
When should one suspect C.difficile infection?
If someone develops Diarrhea within 48-72 hours of being admitted to hospital.
What does C.difficile cause? How?
Colitis.
Produces a toxin.
Clinical signs of C.difficile infection?
High fever
Abdominal cramps
Diarrhoea (normally watery, sometimes bloody)
Pseudomembranous colitis
What is pseudomembranous colitis?
Inflammation of the colon involving the development of a viscous collection of inflammatory cells, fibrin and necrotic cells
How to diagnose C.difficle?
Toxin in stool.
Sigmoidoscopy - look for pseudomembrane
How to treat C.difficile infection?
Rehydration therapy.
Antibiotics.
Which antibiotics are used to treat C.difficile?
Oral metronidazole.
Vancomycin (severe disease).
What is Bacillus cereus a known cause of?
Food poisoning.
