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Last Updated: Wednesday, 13 July, 2005, 19:43 GMT 20:43 UK
On hospital-acquired infections
Hospital Cleaning is a politically charged topic, however the more substantial scientific debate about the links between the hospital environment and hospital acquired infections has not seen corresponding progress. As yet, the evidence is not all there.

Here Dr Mark C. Enright, from the Department of Infectious Diseases Epidemiology at Imperial College, London sets out the facts.

How common are Hospital Acquired Infections in the UK?

Hospital-acquired infections (HAI) are common in the United Kingdom affecting around 9% of the patient population and although comparisons between countries are difficult to make this does not seem to be atypically high.

This figure of 9% was arrived at in studies published in 1981 and 1996 and may be out of date, but what is certain is that many of these cases are due to bacteria which are increasingly difficult to treat due to the evolution of antibiotic resistance.

What is MRSA and how is it treated?

Many different bacteria can be caught in hospital but the most notorious is MRSA - methicillin-resistant Staphylococcus aureus some of which are resistant to many different antibiotics. MRSA was relatively rare in the early 1990s representing only about 1-2% of serious infections caused by this species however this figure rose to more than 45% within 10 years.

MRSA is particularly feared in hospitals as it can cause an extremely wide range of serious disease such as pneumonia, septicaemia, bone infections and toxic-shock and it can only be reliably treated with vancomycin - an antibiotic that is usually given intravenously over a period of several days.

Vancomycin has several side-effects and is relatively toxic, it is also poorly absorbed by the body causing problems in treating deep-seated MRSA infections and pneumonia.

What is C. Difficile and how is it treated?

Clostridium difficile is the major cause of hospital-acquired diarrhoea in many countries where it can cause life-threatening illness especially in elderly and patients with severe underlying disease. Clostridium difficile was responsible for a recently reported fatal outbreak at Stoke Mandeville hospital among elderly patients. Comparisons between this organism and MRSA highlight the difficulties faced by healthcare workers in reducing the number and severity of hospital outbreaks.

Clostridium difficile is commonly found in the large intestine and infections usually occur following long-term antibiotic therapy that kills other bacterial competitors allowing Clostridium difficile to take over. It produces two major toxins that inflame the colon causing diarrhoea.

Contamination of the hospital environment from this source is key in causing and prolonging outbreaks as the bacteria produces spores that can survive on wet or dry surfaces in hospitals for long periods.

Clostridium difficile can be readily treated using vancomycin or metronidazole but importantly it is not killed by alcohol handwashes used by healthcare workers to prevent the spread of MRSA and other infections and is best dealt with using soap and water.

Can hospital cleanliness help in our fight against these infections?

Measures to improve hospital cleanliness may be useful in reducing the numbers of infections due to diarrhoea-causing bacteria such as C. difficile and Enterococcus species, but it is less clear that this will be the case for other pathogens such as MRSA and Acinetobacter species that primarily infect wound sites (especially catheter entry sites) and seem to be largely spread on the hands of healthcare workers directly from colonized patients.

MRSA is ever-present in most hospitals where it can be carried in the nose and on the skin of staff and patients without causing disease. MRSA can persist for months on surfaces and is very hard to eradicate using standard cleaning protocols but it is not obvious that the environment plays a major role in initiating MRSA outbreaks. Research is urgently needed in this area if we are to properly address the problem of HAIs.


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