PCR检测空气样本中的烟曲霉菌（翻译有奖）

潮水

Detection of Aspergillus fumigatus by quantitative polymerase chain reaction in air samples impacted on low-melt agar
American Journal of Infection Control
Volume 38, Issue 3, Pages 195-198 (April 2010)

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.

Key Words: Aspergillus fumigatus, QPCR, fungal surveillance, immunocompromised patients, environmental sampling

天师

PCR检测空气样本中的烟曲霉菌
美国感染控制杂志，2010，38（3）195~198
【背景】曲霉菌暴发时采样常规环境卫生学采样的标准程序进行对压缩空气烟曲霉菌的培养，通常需要7天出培养结果。我们关于空气中真菌孢子常规培养与PCR定量测定两个方法的结果的报告时间、敏感度做了一项基础性研究。
【方法】真菌DNA从43份压缩空气采用三步提取法和QPCR法进行扩增来提取的。检测是用特殊的真菌探针进行的。
【结果】QPCR法，43份样本中19份真菌阳性，19份QPCR阳性中，常规培养方法仅7份为阳性，12份阴性。12份培养阴性标本阈值（Ct）在39~43之间，7份培养阳性的<38，提示QPCR检测的DNA量高于真菌孢子实际量。
【结论】压缩空气真菌QPCR的检测可以缩短采样和采样后48小时报告结果时间，差异具有统计学意义，建议这种新的检测方法有利于缩短环境卫生学常规检测。
[关键词] 烟曲霉菌，定量PCR，真菌监测，免疫功能低下患者，环境采用

潮水

43份样本中19份真菌阳性，19份QPCR阳性中，常规培养方法仅7份为阳性，12份阴性。PCR检测通常假阳性比较高，常规检测是否可行？