Comparison of staining methods and a nested PCR assay to detect Histoplasma capsulatum in tissue sections.
To optimize diagnosis of histoplasmosis in tissue sections, 30 spleen specimens from mice, experimentally infected with Histoplasma capsulatum, were examined by H&E, Grocott stain, anti-bacille Calmette-Guerin antibody immunostain, Fungiqual A fluorochrome stain (Drs Reinehr and Rembold, Kandern, Germany), and a nested polymerase chain reaction (PCR) assay. Results were compared with the tissue burden determined by quantitative culture. By applying logistic regression, the nested PCR assay was the most sensitive method, but not significantly more sensitive than the Grocott stain. The 50% quantile to achieve a positive result was determined to be 3 colony-forming units per milligram of spleen tissue for the PCR assay, 11 for the Grocott stain, 27 for the fluorochrome stain, 190 for immunostaining, and 533 for the H&E stain. The Grocott and fluorochrome stains did not differ significantly in detecting fungal elements. The PCR assay unambiguously identified H. capsulatum in tissue sections.
Bialek
Ralf
R
Institute for Tropical Medicine, University Hospital Tübingen, Germany.
Ernst
Friederike
F
Dietz
Klaus
K
Najvar
Laura K
LK
Knobloch
Jürgen
J
Graybill
John R
JR
Schaumburg-Lever
Gundula
G
D000818:Animals; D000906:Antibodies; D005456:Fluorescent Dyes; D006658:Histoplasma / Q000302:isolation & purification*; D006660:Histoplasmosis / Q000175:diagnosis* / Q000382:microbiology; D016015:Logistic Models; D008709:Methenamine; D051379:Mice; D008807:Mice, Inbred BALB C; D008813:Mice, Inbred ICR; D008819:Mice, Nude; D009163:Mycobacterium bovis / Q000276:immunology; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D012835:Silver Nitrate; D013154:Spleen / Q000382:microbiology / Q000473:pathology; D013194:Staining and Labeling / Q000379:methods*; D013267:Stilbenes; D014227:Triazines
D000906:Antibodies; D005456:Fluorescent Dyes; D013267:Stilbenes; D014227:Triazines; C061166:fungiqual; D012835:Silver Nitrate; D008709:Methenamine