Electronic nose to sniff the whiff of C diff

Electronic nose to sniff clostridium difficile - C diff - bacteria

Clostridium difficile bacteria do not usually cause problems in healthy people. But when antibiotics interfere with the natural balance of the gut flora, antibiotic-resistant C difficile bacteria can multiply rapidly and produce toxins that result in symptoms such as diarrhoea, fever and stomach cramps — sometimes with life-threatening complications.

Speedy detection and identification of C difficile (often shortened to C diff) is a major concern in hospitals. Rapid and accurate diagnoses are important, both for reducing the incidence of C difficile infection generally and for providing the most appropriate treatment for infected patients. Delays in treatment, or starting treatment with inappropriate antibiotics, can lead to high morbidity and mortality and also add to healthcare costs through lost bed days.

But now, hope for a speedier means of diagnosis has been provided by research published in the online journal Metabolomics
by a team from the University of Leicester. Workers from the department of chemistry, in collaboration with one of the university’s microbiologists, have discovered that C difficile adds a distinctive smell to faeces, and that its identification can lead to rapid diagnosis.

Luckily, no poo-sniffing volunteers are needed, because the researchers have developed a sensitive electronic nose using mass spectrometry. The technique can quickly detect specific volatile organic compounds (VOCs) given out by C difficile, allowing diagnosis as soon as the patient manages to produce a sample of faeces.

Of particular interest is that the technique is sensitive enough to pinpoint the chemical fingerprints produced by different ribotypes (strains) of C difficile — information that is not generally provided by current diagnostic tests. The researchers identified 69 small molecular weight VOCs and found that different combinations of these were characteristic for each of 10 ribotypes tested.

Identifying the precise strain of the bacterium is important because different strains can cause different symptoms and need different treatments. A rapid clinical diagnostic tool developed from the Leicester findings could therefore allow doctors to learn immediately which strain of C difficile is causing the illness, allowing them to provide the best treatment option for the infected patient right from the start.

Last updated
The Pharmaceutical Journal, PJ, 18 October 2014, Vol 293, No 7832;293(7832):DOI:10.1211/PJ.2014.20066551

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