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The changing spectrum of Clostridium difficile–associated disease Implications for dentistry

Case 1 (mild CDAD ): A 48-year-old female received antibiotics (oral clindamycin) after undergoing endodontic surgery.  8 days after the antibiotic course, she had diarrhea, she took metronidazole, and her C. difficile infection resolved.

Case 2 (severe CDAD): A 31-year-old pregnant woman developed severe CDAD after receiving antibiotics for a urinary infection. She underwent surgery to remove part of her colon, but her condition worsened, and she died.


Clostridium difficile: is a gram-positive, spore forming, toxin-producing, anaerobic bacillus that causes diseases of the GIT ranging from asymptomatic colonization to a life threatening condition known as “toxic megacolon.”


 It is spread by the fecal-oral route and can be ingested in a vegetative or spore form.

The primary virulence factors are:

the large clostridial cytotoxins toxins A and B that cause inflammation and mucosal damage and lead to diarrhea or colitis. In people who develop CDAD after taking antimicrobial agents, their S&S typically start within 3-weeks of initiating antimicrobial therapy, but they can begin as early as the 1st day of treatment or as late as 2-months after its completion


Mild-moderte CDAD: non-bloody diarrhea with few systemic symptoms.

Moderate CDAD: fever, abdominal pain and leukocytosis. (TX should be initiated at this stage)

Severe CDAD: hemodynamic instability and other signs of a sepsis-like syndrome. The most serious complications

include paralytic ileus, peritonitis and toxic megacolon; in many cases, these complications require surgical removal of the colon.\\

Risk factors:

Taking cephalosporins, penicillins or clindamycin. being older than 65 years, undergoing nasogastric intubation, having severe comorbidities and experiencing long hospital stays

Treatment: discontinue the use of any inciting antimicrobial agents or narrow the spectrum of AB

Prescribe to patients with CDAD a 10-day course of oral antimicrobial agent to treat C. difficile. For mild-to-moderate CDAD, oral metronidazole usually is effective. For severe CDAD, oral vancomycin may be a better choice.


Interaction: Metronidazole may slow the elimination of lithium from the body which will increase blood levels of lithium and cause toxic effects.

  • Tetracyclines or other broad-spectrum antibiotics with oral anticoagulants

Interaction: it has been hypothesized that broad-spectrum antibiotics such as tetracyclines, amoxicillin and ampicillin can reduce endogenous vitamin K levels and enhance the effects of oral anticoagulants by decimating the normal gut flora that produce vitamin

  • Antibiotics with oral contraceptives

Interaction: may lead to subtherapeutic blood levels of combined oral contraceptive and leading to contraception failure. Additional method of contraception is adviced.

With Rifampin antibiotic alternative method is recommended.

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