Electronic nose sniffs out TB

A low-cost breathalyser that can diagnose tuberculosis in around an hour is being developed in the UK with World Health Organisation funding.

A low-cost breathalyser that can diagnose tuberculosis in around an hour, dramatically speeding up treatment of the disease, is being developed in the UK with World Health Organisation funding.

Researchers at Cranfield University have received £45,000 from the WHO to develop a diagnostic device that uses 14 polymer sensors to detect the volatile organic compounds found in the breath or sputum of a TB sufferer.

The WHO is holding its annual World TB Day on Monday, aimed at raising awareness of the symptoms and possible treatments for the disease, which kills around two million people each year. The WHO has warned that the global TB epidemic is growing, as the spread of HIV increases – particularly in the Third World – and theemergence of a strain of multidrug-resistant TB worsens the impact of the disease.

‘The WHO recognised many years ago the global need to improve the way TB is diagnosed and managed,’ said Dr Anthony Woodman, head of the Cranfield BioMedical Centre.

Cranfield’s researchers are working with Amsterdam’s Institute of Tropical Medicine to develop a breath analyser to detect the caustic agents of TB, including compounds found in patients with drug-resistant TB, and TB/HIV.

‘This technology gives us results that are as informative as molecular techniques, which are very difficult and expensive, and not practical for use in environments such as the African bush,’ said Woodman. ‘The ‘electronic nose’ is simple and robust, and can be slimmed down for use in rugged environments.’

Each device would cost around £5,000, and the materials needed for each analysis would cost between 50p and £1. If combined with mobile phone technology, the device would be extremely quick and simple to use, said Woodman.

The researchers eventually hope to produce a breath analyser that acts in the same way as a blood alcohol monitor. But their trial system is based on a vial, into which a small sample of diluted sputum is placed.

Special enzymes are added, and the resulting reaction causes volatile compounds to be released. This contaminated air is sucked into the device, and the chemical interaction between the compounds and the polymer sensors produces a signal that is analysed by a computer.

Devices similar to Cranfield’s are already used in the food and perfume industries, but the neural networks needed to analyse the mass of information within a human medical sample has not been available until recently, said Woodman.

The researchers are testing the device using 200 sputum samples provided by the WHO, and are investigating whether its size can be reduced by using fewer sensors.

At the end of the one-year project, the research team plans to run field trials of the device in the Gambia and in Latvia, which has the highest incidence of drug-resistant TB in Europe.

The technology can also be used to detect urinary tract infections, allowing GPs to prescribe patients with the correct antibiotics within a few hours, rather than waiting days for lab results.

Researchers are investigating the use of the device to detect food contamination.