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| Making Sense of Health, Safety and Related Issues. | ||
Making Sense of ... C-Diff; | |
What is C-diff?C. 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. Clostridium difficile infection is a frequent cause of hospital-acquired diarrhoea, and is readily spread from person to person. Where is C-diff usually found?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 therapy. Hospitals are a key focus, and the problem may be prevalent in other institutions too. How common is C-diff?As 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. How 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. Can 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. Who 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;
What are the symptoms of C-diff?The effects vary from mild to severe watery diarrhoea to severe inflammation of the bowel. 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. How 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?Therapy is based on two principles:
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. If diagnosis 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.
Is 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. Isolation:
Isolation Precautions
Environmental Cleaning
Patient Transfer
What is the C-diff vaccine?Currently, 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 against it. 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 for CDAD." Phase 2 proof-of-principle trials were scheduled to commence before the end of 2006. Can C-diff be controlled environmentally?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. Is 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. What 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. Where can I get more information about C-diff?
I regret I cannot assist with individual cases or essays and school projects, but if it's something I've missed, I'll be happy to try and help. © Andrew Heenan January 2007 | |
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12 May 2008 | 
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