FIG 4 .

Amplification of the MAT and β-tub mRNAs of three P. jirovecii isolates by RT-PCR. RT-PCR analysis was performed with cDNAs obtained from BAL fluid samples from 11 patients with PCP; 3 are shown here as examples. Random amplification of the cDNA proved to be necessary to obtain PCR products. The PCR products were of the expected sizes shown next to the bands. The positive control was genomic DNA extracted from another BAL fluid sample. The matMc PCR products of patients 2 and 3 were obtained during an experiment other than that during which the matMc PCR product of patient 1 was obtained. The identities of the PCR products were confirmed by sequencing.