CONCISE COMMUNICATION Polymerase Chain Reaction Detection of Aspergillus DNA in Experimental Models of Invasive Aspergillosis

To determine the sensitivity of polymerase chain reaction (PCR) assays for the diagnosis of in-vasive aspergillosis, results of quantitative culture, PCR-ELISA, and a quantitative LightCycler assay (Roche Diagnostics) of blood and organ specimens of experimentally infected mice and rab-bits were compared. By PCR-ELISA, 297 of 379 murine lung specimens were positive, but only 235 of 379 were culture positive. Whereas 64 culture-negative lungs were positive by PCR, Aspergillus was grown from only 2 PCR-negative samples. The PCR assay was 19.4 times more sensitive than culture. None of the 68 blood cultures from mice and rabbits were positive for Aspergillus fumigatus, whereas PCR detected Aspergillus DNA in 17 of 68 blood samples. Quantitative PCR analysis of blood samples showed a fungus load of 101–102 cfu/mL of blood. The data confirm the superior sensitivity of PCR for the diagnosis of experimental Aspergillus infections. Aspergillus fumigatus is an opportunistic pathogenic fungus that causes invasive infections in immunocompromised patients, particularly in leukemic patients and in those undergoing allo-geneic stem cell or solid organ transplantation. Therapeutic suc-cess depends on early diagnosis and early initiation of antifunga