Diagnosis of Pneumocystis carinii pneumonia:: Immunofluorescence staining, simple PCR or nPCR

Objectives: to compare immunofluorescence (IF) test, routinely used in the department for the detection of Pneumocystis carinii with simple polymerase chain reaction (PCR) and nested PCR (nPCR) Methods: Bronchoalveolar lavage (BAL) and induced sputum (IS) specimens from HIV-positive (39), lung transplant (2), heart transplant (2), and one each from non-Hodgkin's lymphoma, drug addict and a premature baby were screened by IF test, simple PCR and nPCR for the presence of P. carinii. Results: of the 46 specimens tested, two (4.3%) were positive by IF, 11 (23.9%) by simple PCR and 21 (45.6%) by nPCR, Both simple and nPCR amplified those found positive by IF test. Analysis of the clinical data revealed bath IF positive, 10 of the simple PCR and 15 of the nPCR group were strongly suspected of P. carinii pneumonia (PCP), Two specimens, one from a patient where chest X-ray was suggestive of PCP and the other where past-mortem histology revealed the presence of PCP, were negative by IF test. Conclusion: simple PCR detection may be considered for patients where PCP is suggestive clinically and the specimen is negative by IF test.