At the annual British Thoracic Society meeting in London on December 1st, Dr Caroline Baxter reported the highly sensitive performance of Myconostica‘s real-time PCR assay MycAssay Aspergillus in cystic fibrosis (CF) sputum1 which is 260% more sensitive than the currently used culture. PCR combined with Aspergillus IgG testing on blood was diagnostic for the recently recognized condition in CF – Aspergillus bronchitis, described in 2006 in Leeds for the first time2.
CF affects about 1 in 2500 babies in the UK and leads to a lifetime of lung infection. Aspergillus infection in CF is associated with more rapid lung function decline, and an earlier need for transplantation or death.
Traditional culture methods used to identify Aspergillus in CF are known to be variable and insensitive as well as being slow, taking up to several days to record a positive result. When MycAssay Aspergillus is combined with Myconostica’s fungal DNA extraction system, MycXtra and pretreatment with dithiothreitol and sonication, PCR improves sensitivity dramatically. PCR takes ~3 hours compared with days for culture therefore providing a rapid, sensitive and specific alternative to the conventional techniques used to identify Aspergillus infections. Dr Baxter also showed data that PCR was more sensitive than galactomannan detection, a test used to detect Aspergillus antigen.
She also reported that the PCR result was negative in 5 of 11 (45%) of those on antifungal treatment, suggesting that PCR might be the best way to assess whether antifungal therapy is working. This is potentially of great importance in monitoring therapy in CF patients, as azole antifungal agents are often poorly absorbed and ineffective.
The work in 117 adults attending the Manchester Adult Cystic Fibrosis Unit was conducted in 2010 and concluded that: “Aspergillus PCR has a key role in the future of CF care”.
Commenting on these results, Dr John Thornback, Chief Business Officer of Myconostica said: “The introduction of new technologies such as Aspergillus PCR often results in reappraisal of disease, and this is certainly the case here. Aspergillus PCR is clearly a very sensitive means of detecting this allergic fungus in the airways of CF patients. The early identification of infected patients may open opportunities for early interventions, preventing inexorable decline in lung function in these young people. Myconostica is committed to working with the clinical community to better understand the role that PCR can play in the diagnosis of life threatening fungal infections such as Aspergillosis as early as possible in at risk patient populations such as those with CF."
1. Baxter CG, Jones AM, Webb AK, Denning DW. REAL TIME PCR IN THE IDENTIFICATION AND MANAGEMENT OF ASPERGILLUS IN CF. Abstract S19. Thorax 2010;65 (suppl IV): A11-12. doi:10.1136/thx.2010.150912.19
2. Shoseyov D, Brownlee KG, Conway SP, Kerem E. Aspergillus bronchitis in cystic fibrosis. Chest. 2006 Jul;130(1):222-6.
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