Copyright X 1993, American Society for Microbiology Detection of Aspergillus fumigatus by Polymerase Chain Reaction

AspergiUus fumigatus is an opportunistic nosocomial pathogen causing an often fatal pneumonia, invasive aspergillosis (IA), in immunosuppressed patients. Oligonucleotide primers were used to amplify a 401-bp fragment spanning the 26S/intergenic spacer region of the rDNA complex ofA. fimigatus by the polymerase chain reaction (PCR). The primers were highly sensitive and specific: as little as 1 pg ofA.fumigatus genomic DNA could be detected, and the primers only amplified DNA from A. fumigatus and not any other fungal, bacterial, viral, or human DNA tested. Using the PCR, we were able to detect A. fumigatus DNA in lung homogenates from immunosuppressed mice experimentally infected with A. fumigatus but not from immuno-suppressed uninfected controls. There was 93 % correlation between the culture results and the PCR results. In a retrospective clinical study, the sensitivity of the PCR for the detection ofA.fumigatus in clinical samples was confirmed by positive amplification in three of three culture-positive respiratory samples from confirmed cases of IA. Because isolation ofAspergillus spp. may reflect contamination and colonization without infection, the feasibility of using the PCR was evaluated by analyzing culture-negative samples from both immunosup-pressed patients at high risk for IA and immunocompetent patients with other lung infections. Only 2 of 10 patients were culture negative and PCR positive in the high-risk group, and 2 of 7 patients were culture negative and PCR positive in the immunocompetent group. The results indicate that PCR detection might b