Objectives: Assessment of a real-time PCR technique for the detection and quantification of fungal DNA in a murine model of pulmonary aspergillosis.
Methods: Male ICR specific pathogen-free mice were used in the studies. The animals were divided into groups: immunosuppressed and intranasally inoculated with various inoculum sizes (10(6), 10(5), 10(4), and 10(3) conidia/mL) of a clinical isolate of Aspergillus fumigatus. When symptoms of pulmonary aspergillosis were detected, the mice were killed and the lungs removed for culture and real-time PCR determination. The PCR reactions used primers that amplified a region of Aspergillus spp. ribosomal DNA. Survival time per experimental group was calculated and correlation coefficients with inoculum size, colony counts and PCR results were determined.
Results: Average survival time was significantly associated with the size of the inoculum. Pulmonary colony count was positive for 90% of the infected mice, but there was no statistical relationship between count values and either survival time or inoculum size. Real-time PCR was positive in 100% of the animals and was significantly associated with survival time and inoculum size (p < 0.01).
Conclusion: Real-time PCR is a reliable procedure for the quantification and evaluation pulmonary infection due to A. fumigatus in animal models.