RAPID DIARRHOEA TEST SAVES LIVES

Issue date: 16 February 2004

ISSUE DATE: 16/02/04

Diarrhoea, a worldwide killer, could be diagnosed more successfully thanks to a new, diagnostic test devised by researchers at the University of the West of England and the University of Bristol. It is anticipated that this will lead to the development of a device capable of rapid diagnosis at the bedside, saving both lives and money.

The new test produces a chemical fingerprint for different strains of viral and bacterial infection and allows them to be differentiated from normal controls, according to a recent report ‘Rapid diagnosis of GI infection from flatus’(Gut – January 2004).

The report is the result of a two year collaboration between Professor Norman Ratcliffe at the University of the West of England and Dr Chris Probert from the School of Medicine at the University of Bristol and Consultant Physician at Bristol Royal Infirmary.

Dr Probert said, “There are numerous different kinds of infection that cause diarrhoea and it is important to ensure that the correct diagnoses is made so that the correct treatment can be prescribed. The diagnosis currently requires a microbiological stool analysis which can take up to eight days for results to be obtained. The delay is caused by the need for transport of samples to an appropriate laboratory, and the time required to complete the diagnostic techniques in common use. In some extreme cases samples have been flown from Asia to the US for tests, allowing the disease to spread and kill in the meantime.

“Hospitals in UK wards have sometimes had to close because of the fast spread of viruses, in particular Noravirus, that are not detected early enough for infected patients to be isolated. This causes enormous strain on hospital resources and of course it can be very expensive.”

Professor Norman Ratcliffe who leads the team of researchers at UWE explains. “This test has the potential to reduce mortality and unnecessary suffering and crucially, the spread of infection. It has long been known amongst health professionals that stools have distinctive and different odours if there is an infection. What we have done is to take this ‘knowledge’ a step further by analysing the odour to see if precise chemical fingerprints can be established.

“Put simply the odours known as volatiles from normal, bacterial and viral stools differ significantly. For instance rotavirus which accounts for viral gastroenteritis was discovered to be exclusively associated with ethyl dodecanoate. Using a portable bench top gas chromatography, mass spectroscopy system for analysis, we can identify what volatiles are found in a stool sample in less than an hour of the sample collection being made.

“This study is about to enter its second phase where a larger population of infected samples will be analysed, the ultimate goal for this study will be to develop a portable vapour analysis machine capable of diagnosing at the bedside.”

This pilot project has the potential to save lives and reduce the cost burden to the NHS. Early isolation of infectious patients would reduce hospital outbreaks leading to fewer ward/hospital closures and early diagnosis would lead to more appropriate use of antibiotics. Diarrhoea is a major cause of morbidity and mortality in developing countries and costs the NHS £60 million each year. Every year in England and Wales there are 15,000 cases of ‘clostridium difficile’ infection and worldwide 6,800 children die every day unnecessarily from diarrhoeal disease.

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