Specific detection of Aspergillus and Penicillium species from respiratory specimens by polymerase chain reaction (PCR).

A polymerase chain reaction (PCR) method capable of detecting both Aspergillus fumigatus infections, pulmonary non-fumigatus Aspergillus species (spp.) and Penicillium spp. from clinical specimens was established. The primer pair was designed on the basis of the sequence of the 18S-ribosomal RNA gene of A. fumigatus and P. notatum. A 385 bp product was successfully amplified by this PCR method from all of 12 medically important Aspergillus spp. and Penicillium spp. (38 strains), but not from human, calf, Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), any of 14 medically important yeastlike fungal species tested (32 strains) including Candida albicans, several non-albicans Candida and Saccharomyces cerevisiae, Cryptococcus neoformans, Mucor spp. or Pneumocystis carinii. This specificity was subsequently confirmed by Southern hybridization analysis. The established PCR can detect such a small amount as 1 pg of A. fumigatus DNA by staining the PCR product with ethidium bromide. With sputum specimens from clinically diagnosed aspergilloma patients, this PCR technique was demonstrated to be a more sensitive diagnostic method for Aspergillus infections than conventional culture techniques.