Bellanger AP, Reboux G, Murat JB, Bex V, Millon L. Detection of Aspergillus fumigatus by quantitative polymerase chain reaction in air samples impacted on low-melt agar.
Am J Infect Control 2010;
38:195-8. [PMID:
19896239 DOI:
10.1016/j.ajic.2009.08.003]
[Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 07/31/2009] [Accepted: 08/03/2009] [Indexed: 11/29/2022]
Abstract
BACKGROUND
The standard procedure for routine environmental sampling for the prevention of invasive aspergillosis outbreaks is culturing of Aspergillus fumigatus after impaction of air. Time to results is usually 7 days. A preliminary study was carried out to compare the time to results and sensitivity of culturing and quantitative polymerase chain reaction (QPCR) in the detection of airborne A fumigatus.
METHODS
Fungal DNA was extracted from 43 samples of impacted low-melt agar by a 3-step extraction method and amplified by QPCR. Identification was made using a specific A fumigatus probe.
RESULTS
With QPCR, 19 of the 43 samples were positive for A fumigatus; with culturing, 7 of these 19 samples were positive, and 12 were negative. The cycle threshold (Ct) values for the 12 culture-negative samples were between 39 and 43 cycles, and the Ct values for 6 of the 7 culture-positive samples were <38 cycles, suggesting that the amount of DNA detected by QPCR was higher in the presence of viable conidia.
CONCLUSION
QPCR detection of airborne A fumigatus in impacted low-melt agar significantly reduces the period of time between sample collection and results (48 hours), suggesting that this new approach can be beneficial for routine environmental sampling.
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