Improved diagnosis of Pneumocystis carinii infection by polymerase chain reaction on induced sputum and blood

• Published in: The Lancet (British edition) Vol. 340; no. 8813; p. 203
• Main Authors: Lipschik, G Y, Gill, V J, Lundgren, J D, Andrawis, V A, Nelson, N A, Nielsen, J O, Ognibene, F P, Kovacs, J A
• Format: Journal Article
• Language: English
• Published: England 25-07-1992
• Subjects: Animals; Base Sequence; Bronchoalveolar Lavage Fluid - microbiology; False Positive Reactions; Humans; Molecular Sequence Data; Pneumocystis - genetics; Pneumocystis - isolation & purification; Pneumonia, Pneumocystis - blood; Pneumonia, Pneumocystis - diagnosis; Polymerase Chain Reaction; Prospective Studies; Rats; Sputum - microbiology
• ISSN: 0140-6736
• DOI: 10.1016/0140-6736(92)90469-J

Detection of Pneumocystis carinii by the polymerase chain reaction (PCR) may facilitate non-invasive diagnosis of P carinii pneumonia and study of its epidemiology. We have compared the sensitivity and specificity of two PCR methods with those of conventional staining for detection of P carinii in induced sputum, bronchoalveolar lavage fluid (BAL), and blood. Of 71 sputum samples, 17 were from patients with microbiologically confirmed P carinii pneumonia. A nested PCR method correctly identified the presence of P carinii in all 17 (100% sensitive, 95% confidence interval [CI] 81-100%) and found no organisms in 50 of 54 microbiologically negative samples (93% specific, 95% CI 82-98%). PCR with a single primer pair was 71% sensitive (44-90%) and 94% specific (85-99%). The sensitivity of conventional staining methods (direct and indirect fluorescence antibody and toluidine-blue-O tests) was significantly less (38-53%) than that of nested PCR (p less than 0.05). In BAL, neither PCR method was significantly better than the conventional staining methods. P carinii was detected in BAL or sputum from 10 immunocompromised patients without microbiological evidence of P carinii pneumonia, which suggests that symptom-free carriers or subclinical infection can exist. P carinii was detected by nested PCR in blood from 2 of 3 patients with disseminated pneumocystosis but in only 1 of 11 patients with P carinii infection restricted to the lungs. Nested PCR on induced sputum is more sensitive than conventional staining methods for the diagnosis of P carinii pneumonia and provides a non-invasive method of detecting disseminated disease.