Nucleic acid diagnostic testing for fungal infections

Human fungal infections have emerged as one of the most pressing health problems in recent years. Endemic infections affect healthy immunocompetent individuals causing a range of diseases which generally resolve with chemotherapy but hospital-acquired nosocomial infections pose a serious threat to immunocompromised patients in hospital wards and intensive care units worldwide. Despite the availability of chemotherapy nosocomial infections frequently result in high mortality rates, often exceeding 50%. The development of timely and more efficient molecular diagnostic methods, along with the development of new drugs and anti-fungal vaccines, was recently identified as one of the most pressing needs in medical mycology research.

Current diagnosis of fungal infections traditionally relies on the isolation and identification of fungi from clinical samples but this method is time consuming and lacks sensitivity. Molecular methods based on antigen detection or pathogen DNA amplification have also been developed in recent years but their potential as routine diagnostic methods has so far not been fully realised. This is mostly due to their relative methodological complexity which hampers cost-effective automation. For example fungal DNA amplification by PCR has been demonstrated as a highly sensitive and specific method for the detection of fungi in biological samples, but its requirement for expensive equipment (thermal cyclers) and the use of multiple incubation temperatures and/or temperature gradients has prevented its cost-effective automation and its implementation as a routine diagnostic method in resource constrained medical facilities and diagnostics laboratories worldwide.

This project seeks to develop and implement simple nucleic acids diagnosis methods for a range of fungal infections, including both endemic and opportunistic. We will initially use Candida, the causative agent of endemic and nosocomial candidosis as a test organism. Combining what is already known about diagnostic Candida genes with isothermal DNA amplification, we aim to develop a simple diagnostic method that can be applied at the point of care and which is amenable to future automation.