Rapid diarrhoea test saves lives

Diarrhoea, a worldwide killer, could be diagnosed more rapidly thanks to a new diagnostic test devised by researchers at the University of Bristol and the University of the West of England. It is anticipated that this will lead to the development of a device capable of 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 published in the British Medical Journal ‘Gut’.

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, who is also a Consultant Physician at Bristol Royal Infirmary.

Dr Probert said: “There are numerous 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. Diagnosis currently requires a microbiological stool analysis which can take up to eight days for results to be obtained. This delay is caused by the need to transport samples to an appropriate laboratory, and the time required to complete the diagnostic techniques. In extreme cases samples have been flown from Asia to the US for tests, allowing the disease to spread and kill in the meantime.

“Hospitals wards in the UK have sometimes had to close because of the fast spread of viruses 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 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, or ‘volatiles’, from normal, bacterial and viral stools differ significantly in their chemical composition. By using portable instruments we can identify which volatiles are found in a stool sample in less than an hour of the sample collection being made, and use this information to make a rapid diagnosis.

“This study is about to enter its second phase where a larger population of infected samples will be analysed. The ultimate goal 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. 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, one of the most common causes of diarrhoea, and worldwide 6,800 children die every day from diarrhoeal disease.