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[Comparison of 2 dyes in the detection of Pneumocystis carinii]
L J Casanova-Cardiel1, R Cedillo-Rivera, G Garduño-Rodríguez
1Hospital de Infectología, Centro Médico La Raza, IMSS Vallejo y Jacarandas, México, D.F.
Objective:
To evaluate two staining procedures used in the detection of P. carinii.
Material And Methods:
Bronchoalveolar lavage samples were obtained from 20 immunosupressed rats. The samples were stained by three procedures: o-toluidine blue (OTB), Diff Quik (DQ), and a silver stain as the gold standard. The microscopic search for P. carinii was made independently by two observers.
Results:
Fifteen of the 20 samples were positive to P. carinii with the silver stain. The sensitivity with DQ was 27% and the specificity 100%. With OTB the sensitivity was 93% and the specificity was 80%. The inter-raters' agreement by kappa was 0.11 for DQ and 0.53 for OTB.
Conclusion:
Our results suggest that the silver stain should be used for an adequate diagnosis of pneumonia caused by P. carinii.