title: Detection of Aspergillus fumigatus by quantitative polymerase chain reaction in air samples impacted on low-melt agar.
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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Parasitology-Mycology, University Hospital Jean Minjoz, Besançon, France. apbellanger@chu-besancon.fr
authors.forename: Anne-Pauline
authors.initials: AP
authors.lastname: Bellanger
authors.forename: Gabriel
authors.initials: G
authors.lastname: Reboux
authors.forename: Jean-Benjamin
authors.initials: JB
authors.lastname: Murat
authors.forename: Valerie
authors.initials: V
authors.lastname: Bex
authors.forename: Laurence
authors.initials: L
authors.lastname: Millon
mesh_terms: D000362:Agar; D000391:Air Microbiology; D001232:Aspergillus fumigatus / Q000302:isolation & purification*; D001431:Bacteriological Techniques / Q000379:methods*; D003470:Culture Media / Q000737:chemistry*; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D003470:Culture Media; D000362:Agar