Clostridium difficile

Clostridium difficile




MORPHOLOGY:

  • Gram-positive, rod-shaped, spore-forming bacteria. 
  • Anaerobic

In the presence of oxygen on an inanimate surface:

  • Vegetative form of C. difficile can survive up to 24 hours 
  • Spores can survive up to 2 years on inanimate surfaces
  • Inhabits the microflora of intestines of humans
  • Spores are subterminal
  • Ideal condition for growth is around 37ºC (98.6 ºF)
  • Human perfect host
  • Moves via peritrichous flagella.
  • Shows fecal-oral transmission
  • Asymptomatic fecal carriage is very common in healthy neonates.

RISK FACTORS:

  • Prolong antibiotic therapy 
  • Important antibiotics associated with C. difficile infection:
  •  Clindamycin, ampicillin, and cephalosporins (cefotaxime, ceftriaxone, cefuroxime, and ceftazidime)
  • Fluoroquinolones (ciprofloxacin, levofloxacin, and moxifloxacin)
  • Less risk:  Ticarcillin/clavulanate and piperacillin/tazobactam. 
  • Pantoprazole increases the risk
  • Associated with use of rectal thermometer
  • Old age
  • Enteral tube feeding

VIRULENCE : 

  • Two major toxins -toxins A and B
  • Glucosylate the GTP binding proteins
  • Disrupt cell cytoskeleton
  • Fiud is leaked leading to whitish yellow plaque formation over, colon known as Pseudomembranous colitis.

Other virrulence factor are:

  • Fimbriae 
  • Ability to associate with gut cells/mucus
  • Production of a capsule
  • Secretion of a range of hydrolytic enzyme
  • Production of other toxins (such as an actin-specific ADP-ribosyltransferase by some strains)

SIGNS & SYMPTOMS:

  • Watery diarrhea (at least three bowel movements per day for two or more days)
  • fever, loss of appetite, nausea, abdominal pain/tenderness .
  • May cause crohn’s disease
  • More severe cases of Clostiridium difficile infection present with ulcerative colitis which can be severe enough to result in the need for a bowel resection.
  • Signs and symptoms of colitis can include the above list as well as dehydration and bloody stool.
Complication
  • Toxic megacolon
  • Sepsis.
Infants
  • Don’t develop symptomatic CDAD
  • They lack receptors for mucosal toxin 

DIAGNOSIS:  

  • The cytotoxin assay is the standard test for identification
  •  A fresh stool sample is needed and no prep is required.
  • Other tests include endoscopy and anaerobic cultures.
  • 3 unformed stools per 24h for 2days 
  • Toxin A or B detected in the stoo
  •  Pseudo membranes seen in colonoscopy 
  • There is also a disctinct odor when the feces contains Clostridium difficile.

CONTROL & TREATMENT: 

  • The first step that should be taken is to stop administering currently prescribed antibiotics to the patient. 
  • In mild cases of Clostridium difficile infection, Metronidazole is administered. 
  • In severe cases, treatment can begin with the administration of Vancomycin but can also require surgical intervention.
  •  Alternative drugs are fusidic acid, teicoplanin, and bacitracin.
Exam Question
 

MORPHOLOGY:

  • Gram-positive, rod-shaped, spore-forming bacteria. 
  • Anaerobic
  • Inhabits the microflora of intestines of humans
  • Spores are subterminal

RISK FACTORS:

  • Prolong antibiotic therapy 
  • Pantoprazole increases the risk
  • Associated with use of rectal thermometer

VIRULENCE : 

  • Two major toxins -toxins A and B
  • Fiud is leaked leading to whitish yellow plaque formation over, colon known as Pseudomembranous colitis.

SIGNS & SYMPTOMS:

  • Watery diarrhea (at least three bowel movements per day for two or more days)
  • fever, loss of appetite, nausea, abdominal pain/tenderness .
  • May cause crohn’s disease
DIAGNOSIS:  
  • 3 unformed stools per 24h for 2days 
  • Toxin A or B detected in the stool
  •  Pseudo membranes seen in colonoscopy 
  • There is also a disctinct odor when the feces contains Clostridium difficile.

CONTROL & TREATMENT: 

  • In mild cases of Clostridium difficile infection, Metronidazole is administered. 
  • In severe cases, treatment can begin with the administration of Vancomycin but can also require surgical intervention.
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