treatment, Metronidazole, taken by mouth, is often prescribed as the first choice; if this is
not effective, then another antibiotic Vancomycin, also taken by mouth can be tried.
There is a risk of a relapse of symptoms in about 20/30% of patients, and further courses
of these antibiotics may be required.
CLOSTRIDIUM DIFFICILE DIARRHOEA
What is Clostridium difficile?
In the last two decades, Clostridium difficile has been recognised as a cause of
diarrhoea, usually acquired during a hospital admission, which occasionally, and
particularly in the elderly, may result in a serious illness and even death.
A
number of large outbreaks or epidemics have recently been recognised.
Two
features of this bacterium are of special interest; one is the production of toxins
which can damage the cells lining and bowel, and the other is the ability to form
spores which enable this bacterium to persist in the environment. Not all strains
of C.difficile toxin, and patients colonised by such strains remain healthy
What does Clostridium difficile cause?
Almost all patients who develop C.difficile diarrhoea are on, or have recently been
given, antibiotic therapy. Diarrhoea is the most common symptom but abdominal
pain and fever may also occur. In the majority of patients, the illness is mild and
full recovery is usual. Elderly patients may become seriously ill with dehydration
as a consequence of the diarrhoea. Occasionally patients may develop a severe
form of the disease called “pseudomembranous colitis” which is characterised by
significant damage to the large bowel. This may lead to a grossly dilated bowel
with even rupture or perforation. Unlike some other causes of diarrhoea, it is rare
for C.difficile to spread to other parts of the body such as the blood stream.
How is Clostridium difficile diagnosed?
Any patient who is on, or has received a course of antibiotics within the past few
weeks and complains of diarrhoea, should be considered as possibly having
C.difficile associated diarrhoea.
In the laboratory the detection of the toxin
specifically produced by C.difficile in the faeces of patients with diarrhoea is the
most reliable way of confirming the diagnosis. Therefore, one or more faeces
specimens should be sent to the microbiology laboratory requesting that a specific
investigation for C.difficile is undertaken. Such tests are not routinely performed
on all faeces specimens but are recommended for specimens from high-risk groups
such as those on antibiotics and elderly patients in hospital. The bacterium may
be grown on special culture medium but its isolation alone does not conclusively
prove the diarrhoea is due to this organism. Strains of C.difficile which do not
produce the toxin are unlikely to cause diarrhoea. Direct examination of the bowel
by sigmoidoscopy and taking small biopsics for analysis may also help in confirming
a diagnosis especially in suspected pseudomembranous colitis, but these
procedures are not always available. X-ray investigations are sometimes helpful.
How is Clostridium difficile treated?
Fortunately, most patients develop only a mild illness and stopping the antibiotics
together with fluid replacement, either by mouth or intravenous drip, usually results
in rapid improvement. Sometimes, however, it is necessary to give specific therapy
against the C.difficile bacterium.
Two antibiotics are known to be effective in
How is spread of Clostridium difficile prevented?
Patients with diarrhoea, especially if severe or accompanied by incontinence, may
unintentionally spread the infection to other patients. In addition, the ability of this
bacterium to form spores enables it to survive for long periods in the environment, eg on
floors and around toilets. This is unlike other causes of diarrhoea such as Salmonella.
Infected patients should be segregated from non-affected patients, preferably in a single
room and disposable gloves and aprons should be used by staff when caring for infected
patients.
Rigorous cleaning with warm water and detergent is probably the most
effective means of removing spores from the contaminated environment.
Hand
washing before and after patient contact remains, however, the most effective control
measure in preventing person-to-person spread of this infection.
What is the risk to health care workers and patient’s relatives?
Because most patients with this condition have recently received antibiotics, hospital
staff such as nurses and doctors, and patient’s relatives, are at little risk of catching the
illness themselves. However, should these people be receiving antimicrobials, then they
may be at some risk, and therefore, they should be especially scrupulous in their
handwashing.
What is the significance of asymptomatic carriage of Clostridium difficile?
Patients without diarrhoea do not need to be tested for the presence of this bacterium or
its toxin as a proportion of the normal population, eg the elderly and the very young, will
carry this bacterium as part of their normal bowel flora. Faeces specimens should only
be sent to the laboratory to make a diagnosis from patients with symptoms, so that
appropriate infection control measures may be instituted and specific treatment started
if required. Usually, once a diagnosis has been confirmed, repeat specimens need not
be taken unless there is a relapse following treatment. In fact it is not uncommon for
the faeces to remain positive for some time after the start of treatment even when the
symptoms have settled.
How can this infection be prevented?
The sensible use of antibiotics is the key to the prevention and control of C.difficle
infection. Where possible, short courses of antibiotics of only three to five days are
preferred to longer courses.
In addition, narrow-spectrum antibiotics eg penicillin,
which only kills a small range of bacteria, are preferred to broad-spectrum agents, which
can have an effect on a wide range of bacteria. Both of these features of antibiotic
therapy will minimise the alteration of the normal bacterial flora of the bowel, which is
the key factor in the development of this condition.
A short course of a narrowspectrum antibiotic is particularly advisable when the precise cause of a bacterial
infection is known. Finally, when a patient is identified as having C.difficile diarrhoea,
the infection control measures already described will minimise the risk of spread to
others.
Association of Medical Microbiologists 1995ISBN 0 952044 64