Abstract:

Objective To establish a diagnosis method for fungal infection using two-round PCR, and to evaluate its sensitivity in the detection of clinical specimens suspected to be infected with fungi. Methods A total of 29 specimens of clinical sputum and alveolar wash solution were collected from patients with suspicious fungal infection. All specimens underwent direct microscopy with 10% KOH, fungal culture, one-round PCR and two-round PCR. The fungal universal primer targeting ITS regions of rDNA was used in PCR. The detection rate for fungi was compared between these methods. Results The detection rate for fungi was 20.69% by direct microscopy, 37.9% by fungal culture, 17.2% by one-round PCR, and 48.3% by two-round PCR. More than one species of fungus were detected in 6.9% （2/29）, 3.4% （1/29） and 24.1% （7/29） of these specimens by fungal culture, one-round PCR and two-round PCR, respectively. There was a significant difference in the detection rate between two- and one-round PCR （χ2 = 6.34，P < 0.05）. With regard to the detection rate for more than one species of fungus, two-round PCR was significantly higher than one-round PCR and fungal culture （χ2 = 4.09, 6.30，both P < 0.05）. Conclusion Two-round PCR may help to improve the sensitivity of molecular diagnosis of fungus-infected specimens.