What is C-diff?
difficile is an anaerobic bacterium. It thrives in the large intestine, where
there is very little oxygen. It occurs 'normally' in about 3-5% of healthy adults,
and is common in babies and infants. In adults, it is usually kept under control
by the normal bacteria of the intestine; it does not cause disease in infants,
because the toxin produced by the bacteria does not damage their intestinal cells.
difficile infection is a frequent cause of hospital-acquired diarrhoea, and is
readily spread from person to person.
Where is C-diff
The infection is a major cause of antibiotic associated
diarrhoea - opportunistically causing problems in people weakened by co-existing
disease, whose natural defensive bacterial may have been reduced by antibiotic
Hospitals are a key focus, and the problem may be prevalent in
other institutions too.
How common is C-diff?
the problem was not recognised until the 1970s, and is still seriously underreported
(most diarrhoea is never properly diagosed), the full prevalence is simply unknown.
One ten year study at a large hospital found 908 cases, of whom 2% died
before treatment was commenced; not necessarily direcly due to the infection.
In those treated, there was a 0.6% mortality rate.
is C-diff transmitted?
Clostridium difficile can occur asymptomatically
in over a third of hospitalized adults, and the bacterium can produce a hardy
spore that may persist for many months. These spores have been found on almost
every item available in hospital wards, but person-to-person transmission via
the hands of healthcare workers is probably the main vector of transmission.
C-diff be spread from person-to-person?
Very easily; patients and satff
may be colonized with the bacteria; carrying the disease potential, but without
symptoms, staff may transfer the infection from person to person, either by moving
the bacteria, or transferring spores by moving contaminated items.
is most at risk from C-diff?
Patients treated with antibiotics have the
highest risk. In most cases, those affected are older people with co-existing
conditions. Patients in the same ward as infected persons are also at risk; epidemics
have occurred in hospitals, nursing homes and other institutions, but the infection
also occurs in the home.
Specific risk factors have been identified;
- Admission to intensive care unit
- Advanced age
- Antibiotic therapy
- Multiple and severe underlying diseases
- Placement of a
- Prolonged hospital stay
- Recent surgical procedure
in a nursing home
- Sharing a hospital room with an infected patient
However, a review of the research found that the evidence
supporting clinical prediction rules is weak and flawed,
and calles for prospective studies to improve risk assessment
What are the symptoms of C-diff?
effects vary from mild to severe watery diarrhoea to severe inflammation of the
Symptoms can also include nausea and abdominal pain or tenderness,
fever, loss of appetite.
Patients with the infection can be clinically relatively
well; simply carriers of mildly pathogenic bacteria. Some may report recurrent
diarrhoea but may not be concerned with the symptoms. Others may have recurrent
bouts of severe cramps, diarrhoea and other symptoms. Unless C-diff is diagnosed,
these patients could well be mis-diagnosed with Irritable Bowel Syndrome, while
presenting a real risk to other people.
What are the
long term effects of C-diff?
C-diff is more than just diarrhoea; the patient
may become dehydrated, and pre-existing conditions may be worsened. Loss of appetitie,
particularly if nausea is present, can lead to weakening and loss of muscle tone.
Even an uncomplicated recovery may take several weeks in a previouslt fit person.
On occasions, much longer.
What is the mortality
rate for C-diff?
Clostridium difficile infection still carries a mortality
rate of 1 to 2.5 percent. This disguises a large variation,
depending on prompt diagnosis and effective treatment.
The infection typically srikes hospitalised older
people; a population in which diarrhoea is not uncommon.
Deaths are likely to occur early in an outbreak, before
the problem has been identified and taken seriously.
Later affected people will be more likely to have stools
tested, infusions set up to replace lost fluids, and
receive antibiotics. One study suggests that statistics
based on death certificates - reporting 6-30% mortality
- may be inaccurate; it is likely that only deaths
within 30 days of C Diff diagnosis should be attributed to
the infection (Hota 2012)
is C-diff diagnosed?
The most common confirmatory study is an enzyme immunoassay
for C. difficile toxins A and B. The test is cheap and easy, with results available
in two to four hours. Specificity of the assay is high (90 to 100 percent), but
sensitivity ranges from 80 to 90 percent. In severe cases, flexible sigmoidoscopy
can provide an immediate diagnosis.
C. difficile grown from cell culture
is the most sensitive test, but this takes 48-72 hours; culture may be used when
enzyme assays fail to provide a clear diagnosis and direct colonic examination
cannot be performed.
Is there a treatment for C-diff?
is based on two principles:
- Discontinue antibiotics.
Prophylactic antibiotic therapy should not be
given routinely, but once the diagnosis has been confirmed, selected patients
may be given metronidazole - orally is preferred. If fluid replacement and nutritional
intake have not been compromised, this may not be necessary.
considered to be highly likely (eg other patients have already had a confirmed
diagnosis) and the patient is seriously ill, metronidazole may be given empirically
before the diagnosis is established.
- Vancomycin, given orally, is
never used as routine, but may be considered if:
- The infection has not
responded to metronidazole (or culture confirms that the strain is resistant to
- The patient is allergic to or cannot tolerate metronidazole,
or is being treated with ethanol-containing solutions.
- The patient is
either pregnant or a child under 10 years of age.
- The patient is critically
ill because of C difficile-associated diarrhea or colitis.
- There is evidence
suggesting the diarrhea is caused by Staphylococcus aureus.
there a way to prevent infection?
Hospitals and long term care facilities
can become reservoirs of infection. C-diff spores can survive for months; the
organism can be cultured from residents and from everything around infected residents,
as well as the hands of health care workers.
Unless there is already a problem
with C-diff, simple hygiene, both personal and environmental, is all that is required,
provided staff are alert to the possible significance of diarrhoea and which residents
are at risk.
Where a problem exists; either an outbreak or isolated cases,
more aggressive action will be required to prevent further spread of the infection.
- A private room is recommended, especially for residents who are fecally incontinent
or who cannot practice good handwashing.
- Cohort symptomatic residents
only with other symptomatic residents.
- Because of the high probability
of environmental contamination, persons with C. difficile-associated diarrhea
(CDAD) should share toilets only with other CDAD residents.
may be discontinued when the diarrhea ceases.
- Communal activities may
also resume when diarrhea ceases.
- Contact precautions should be used for CDAD residents with diarrhea.
Hands should be washed frequently with soap and water.
- Alcohol-based hand
gels and lotions are ineffective in CDAD and are not recommended.
should be worn when entering the room.
- Apron or gowns should be worn if
physical contact with the resident or the environment is anticipated.
Equipment should be dedicated to the infected patient
- Precautions continue
until diarrhea is reduced to fewer than three stools per day.
- A system
in place to alert healthcare workers and visitors that a resident requires contact
precautions, without compromising that resident's privacy.
- The immediate environment should be cleaned thoroughly
at least twice per day, with special attention to items likely to be contaminated:
- An effective disinfectant-detergent should be used
in an appropriate concentration.
of patients with confirmed C.difficile colonization or disease must be
preceded by notice that the patient has CDAD.
- Planned transfers should
not be delayed by the infection, provided the receiving organisation can safely
accomodate the person.
What is the C-diff vaccine?
no vaccine exists against C. difficile. Acambis has been developing such a vaccine
for several years; they are the only company known to be developing a vaccine
Recently completed phase I trials were designed to test safety,
tolerability and immunogenicity of the C. vaccine at different dose levels. The
randomised, double-blind, placebo-controlled studies in healthy adults were being
conducted at two study centres in the US. Further phase I trials are expected
to involve older people as subjects.
Acambis, commented: "These results
are encouraging and show that subjects vaccinated with our C. difficile vaccine
developed high levels of antibodies against toxins A and B, the toxins responsible
Phase 2 proof-of-principle trials were scheduled to commence
before the end of 2006.
Can C-diff be controlled
Because of it's ability to produce long-lasting spores,
eradication of C-diff in healthcare instituions is probably impossible; but the
risks of outbreaks and epidemics can be minimised with thorough cleaning. Recent
epidemics have occurred in settings of institutionalised filth, with healthcare
institutional cleanliness being little more than a bad joke.
there legal protection for workers and others?
Where risks are known and
understood, then employers and health care facilities have a duty of care. Where
this duty is ignored or treated as a joke, then there is a legal remedy.
can be learned from history?
For too long, C-diff has not been taken seriously.
It is fashionable to blame several fatal epidemics since 2000 on the emergence
of more virulane tstrains of the disease. While there is some truth to that, there
is equally strong evidence that in most cases, there was a culture of neglect
of basic cleanliness and hygiene; an environment waiting for an epidemic to happen.
and Further Information Sources
Chakra, C.N.A. et al., Prediction
Tools for Unfavourable
Outcomes in Clostridium
difficile Infection: A
Systematic Review PLoS One. 2012; 7(1): e30258
Hota, S. S. et al., (2012)
Mortality Rates Attributable
to Clostridium difficile
Infection Emerg Infect Dis. 2012
February; 18(2): 305–307
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Article written by Andrew Heenan BA (Hons), RGN, RMN