II-A. Systemic Bacteriology | 20. Clostridia causing gas gangrene, C. difficile

Question 1

I. Clostridium perfringens
1. What are the main features of Clostridium genus?

Answer 1

1. Gram-positive, anaerobic, spore forming rods
   - endospore deforms the bacterium
   - usually have flagella (except C. perfringens)
2. spores can survive for a long time in environment
3. most species could be present in normal GI microbiota

Question 2

I. Clostridium perfringens
2. What are the important species of Clostridium genus?

Answer 2

1. Clostridium perfringens
2. Clostridium tetani
3. Clostridium botulinum

Question 3

I. Clostridium perfringens
3. What are the main features of Clostridium perfringens?

Answer 3

• double haemolytic zone on blood agar (beta + alpha)
• intensive gas production during metabolism
• usually normally present in GI microbiota in low numbers

Question 4

I. Clostridium perfringens
4. What are the virulence factors of Clostridium perfringens? (ACHED)

Answer 4

• alpha-toxin (lecitinase)
• collagenase
• hyaluronidase
• enterotoxin (CPE)
• DNase

Question 5

I. Clostridium perfringens
5. What are the diseases caused by Clostridium perfringens?

Answer 5

1. Gas gangrene, then blood stream infection
2. Food poisoning (vomiting, diarrhoea)

Question 6

I. Clostridium perfringens
5. What are the features of gas gangrene?

Answer 6

Gas gangrene, then blood stream infection
- usually begins as a wound infection
- rapidly progressing tissue damage
+) Gas production ➡ crepitation

Question 7

I. Clostridium perfringens
6. How do we diagnose diseases caused by Clostridium perfringens?

Answer 7

Question 8

I. Clostridium perfringens
7. What is the empirical therapy for Clostridium perfringens?

Answer 8

1. rehydration in food poisoning
2. wound care
3. necrectomy, lavage, drainage
4. penicillins
5. lincosamids (clindamycin)

Question 9

II. Clostridioides genus
1. What are the features of Clostridioides genus?

Answer 9

• Gram-positive, anaerobic, spore forming rods
• might be present in the normal GI microbiota in low numbers

Question 10

II. Clostridioides genus
2. What is the important species of Clostridioides genus?

Answer 10

Clostridioides difficile (Cdiff)

Question 11

II. Clostridioides genus - Clostridioides difficile (Cdiff)
3. What are virulence factors of Clostridioides difficile (Cdiff)?

Answer 11

• toxin A (enterotoxin)
• toxin B (cytotoxin)

Question 12

II. Clostridioides genus - Clostridioides difficile (Cdiff)
4. What is the pathomechanism by Clostridioides difficile (Cdiff)?

Answer 12

“infection”: upon dysbiosis developed as a result of long antibiotic treatment

• inbalance in the ratio of different bacterial species
• overgrowth of Clostridioides difficile ➡ toxin production increases
  +) enterocyte necrosis ➡ inflammation, pseudomembrane formation
• symptomatic patient might spread the disease to others!

Question 13

II. Clostridioides genus - Clostridioides difficile (Cdiff)
5. How do we diagnose diseases caused by Clostridioides difficile (Cdiff)

Answer 13

Clostridioides difficile (Cdiff)

Question 14

II. Clostridioides genus - Clostridioides difficile
6. What is the empirical therapy for Clostridioides difficile?

Answer 14

• oral glycopeptides (vancomycin)
• metronidazol, fidaxomicin
• fecal microbiota transplantation (FMT)

Question 15

I. Clostridioides genus - Clostridioides difficile
7. What is the prevention for Clostridioides difficile?

Answer 15

• proper antibiotic usage
• proper handwashing with soap and water (alcohol- based disinfectants can not kill the spores!)
• flexi-seal system (stool catether)