Clostridium difficile Agent Information Sheet

Boston University
Research Occupational Health Program (ROHP)
617-414-7647

Agent

The Clostridia species are gram-positive, rod-shaped, spore-formers. They are generally obligate anaerobes and are ubiquitous saprophytes or part of the normal flora. Clostridium difficile is an opportunistic pathogen that produces large, oval, subterminal spores and two toxins. Toxin A is an enterotoxin that causes fluid accumulation in the intestine while toxin B is a cytopathic agent. C. difficile flourishes when antibiotics eliminate the normal intestinal flora.

Disease/Infection

The following diseases are caused by strains of C. difficile:

  • difficile can cause a range of diseases from diarrhea, pseudomembranous colitis to life threatening surgical condition called toxic megacolon.
  • Some individuals, with long term exposure to healthcare facilities or frequent hospitalizations, may be chronic carriers of C difficile

Pathogenicity

Opportunistic pathogen, broad-spectrum antibiotic therapy eliminates competing gut flora, allowing the overgrowth of C. difficile; important cause of antibiotic-associated diarrhea and pseudomembranous colitis; diarrhea in cancer patients receiving chemotherapy; symptoms range from mild diarrhea to severe colitis (possibly fatal).

Biosafety Information

Risk Group/BSL
RG 2/BSL-2
Biosafety Level 2 Practices

Modes of Transmission
Fecal-oral contact; evidence for transmission via fomites and hands exists

Transmission
Skin Exposure (Needlestick, bite, or scratch):Direct contact with bacteria, spores or toxins
Mucous Membrane Splash to Eye(s), Nose or Mouth:Yes
Inhalation:Remote
Ingestion:Yes

Host Range/Reservoir
Humans and other animals

Symptoms
C. difficile can cause a spectrum of clinical manifestations including watery diarrhea and mild abdominal cramping and tenderness. More severe colitis can be marked by:

  • Watery or bloody diarrhea 10 to 15 times a day
  • Severe abdominal cramping
  • Fever
  • Hematuria or pyuria
  • Nausea
  • Dehydration

Fulminant colitis can present with above symptoms and additionally, abdominal distension and severe pain with possible shock.

Incubation Period
Not known

Viability
Spores are fairly resistant; moderate susceptibility to 1% sodium hypochlorite; susceptible to high level disinfectants (>2% glutaraldehyde) with prolonged contact time.

Spores are resistant to heat (spores destroyed by moist heat – 121°C for at least 15 min).

Survival Outside Host
Spores can survive for long periods outside of host.

Information for Lab Workers

Laboratory PPE

Laboratory coat; gloves and safety glasses or face shield are recommended when direct contact with infectious materials.

Containment

BSL-2 practices and containment equipment are recommended for activities involving work with known clinical specimens or cultures of C. difficile.

In Case of Exposure/Disease

  • For injuries in the lab which are major medical emergencies (heart attacks, seizures, etc…):
    • Medical Campus: call or have a coworker call the Control Center at 4–4144.
    • Charles River Campus: call or have a coworker call campus security at 617-353-2121.
      You will be referred to or transported to the appropriate health care location by the emergency response team. 
  • For lab exposures (needle sticks, bite, cut, scratch, splash, etc…) involving animals or infectious agents, or for unexplained symptoms or illness call the ROHP 24/7 hour number (1-617-414-ROHP (7647); or, 4-ROHP (7647) if calling from an on-campus location) to be connected with the BU Research Occupational Health Program (ROHP) medical officer. ROHP will refer you to the appropriate health care location.
  • Under any of these scenarios, always inform the physician of your work in the laboratory and the agent(s) that you work with.
  • Provide the wallet-size agent ID card to the physician.

Vaccination

None available

Information for First Responders/Medical Personnel

Public Health Issues

Person to person transmission can occur through touch or via fomites, or environmental reservoirs through spores. Standard precautions, including gown and gloves, should be used when carrying for someone with active C. difficile disease, both as personal protection measure and to decrease spread.

Diagnosis/Surveillance

Toxins produced by C. difficile bacteria can usually be detected in a sample of your stool. There are several main types of lab tests (enzyme immunoassay, polymerase chain reaction and tissue culture assay). Most labs use the enzyme immunoassay (EIA) test, which is faster but can produce a false-positive result. PCR based tests are also available and more accurate. The diagnosis of pseudomembranous colitis entails visualization of characteristic findings on sigmoidoscopy and should be suspected in those with severe disease.

First Aid/Post Exposure Prophylaxis

Perform one of the following actions:

Skin Exposure (Needlestick or scratch):Immediately go to the sink and thoroughly wash the wound with soap and water for 15 minutes. Decontaminate any exposed skin surfaces with an antiseptic scrub solution.
Mucous Membrane Splash to Eye(s), Nose or Mouth:Exposure should be irrigated vigorously.
Splash Affecting Garments:Remove garments that may have become soiled or contaminated and place them in a double red plastic bag.

Treatment

Antibiotic therapy with metronidazole or oral vancomycin. In refractory cases, Fidaxomicin is also used.

References

Public Health Agency of Canada; http://www.phac-aspc.gc.ca/lab-bio/res/psds-ftss/msds36e-eng.php

Mayo Clinic; http://www.mayoclinic.org/diseases-conditions/c-difficile/home/ovc-20202264

Medical Microbiology, Southern Illinois University:

Microbiology and Immunology, University of S. Carolina School of On-Line Medicine;
Revised: 7/20/2012

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