A simple, low cost method to detect toxins from the organism causing the wasting disease Buruli ulcer has been developed by US scientists. 

Buruli ulcer is a wasting disease caused by organisms called Mycobacterium Ulcerans, which are in the same group as the organisms causing leprosy and tuberculosis. Early diagnosis and treatment are vital as delayed treatment may cause irreversible deformity, long-term functional disability such as restriction of joint movement, extensive skin lesions and sometimes life-threatening secondary infections. 

Polymerase chain reaction of M.ulcerans DNA is commonly used to detect the infection, but is expensive and difficult to maintain reliably say Yoshito Kishi and Thomas Spangenberg from Harvard University, Cambridge. They have created a simple but highly sensitive fluorescent detector for mycolactones, the toxins secreted by M. Ulcerans and distributed within the infected tissue. 

Mycolactones are known to behave well in thin layer chromatography producing a distinct spot on silica gel say Kishi and Spangenberg, but the sensitivity is low. The pair used boronic acids to selectively bind to the mycolactone enhancing the fluorescent emission and allowing detection of levels as low as two nanograms of mycolactones. 

'This is an exciting prospect which will be received with great interest,' says Mark Wansbrough Jones, chair of the World Health Organisation technical advisory group for Buruli ulcer. 'It has potential use as a diagnostic tool which is important because clinical diagnosis is only 70% likely to be correct and a simple test such as microscopy for the bacteria is less than 50 % sensitive.' 

This simple and cost effective method would be particularly useful in the remote areas known to suffer from this disease, say Kishi and Spangenberg. And they are now investigating whether the technique can be developed into an effective way to diagnose Buruli ulcer in its early stages. 

Rachel Cooper 

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