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Processing of Bronchoalveolar Lavage Fluid and Matched Blood for Alveolar Macrophage and CD4+ T-cell Immunophenotyping and HIV Reservoir Assessment
Published on: June 23, 2019
Comparison of methods for identification of Pneumocystis carinii in bronchoalveolar lavage fluid
Wilai Saksirisampant1, Boonchauy Eampokalap, Rosarin Chantharodevong
1Department of Parasitology, Faculty of Medicine, Chulalongkom University, Bangkok, Thailand.
Abstract:
Pneumocystis carinii pneumonitis in one of the most common life-threatening opportunistic infections in patients with AIDS. The definitive diagnosis of this infection can be established only by demonstration of the organism in clinical specimens. This study was a comparison of methods that provide easy recognition of the organism which is readily available, simple and can be performed rapidly in laboratory-diagnosis. Bronchoalveolar lavage fluids obtained from 35 AIDS patients suspected of having Pneumocystis carinii pneumonitis were examined by three staining methods for the presence of Pneumocystis carinii. With Giemsa stains, P. carinii could be identified in 18 cases (51.4%). Three developmental stages: "cyst", "sporozoite" and "trophozoite" were seen. The contrast of organisms against host cells was not outstanding in these stains. Toluidine blue O stains provided easy recognition of the organisms, with marked contrast between the cysts and host cells. 21 cases (60%) were positive in these stains, but the intracystic structures and trophozoites could not be identified. It was suggested that the clinical specimen should be stained first with toluidine blue O which is more rapid and permits easy recognition of the cyst clusters. If the sporozoites and trophozoites had to be identified, Giemsa stains can be made. In addition, with the methenamine silver nitrate stains, 21 cases (60%) were positive. They revealed the morphology as seen with toluidine blue O but the cost of material may make it unavailable in many laboratories especially with the budgetary restraints of developing countries.
Insights
Diagnosing Pneumocystis pneumonia in AIDS patients requires identifying the organism. Toluidine blue O and Giemsa stains offer rapid, effective methods for detecting Pneumocystis carinii in clinical samples.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Diagnostic Pathology
Background:
- Pneumocystis carinii pneumonia is a critical opportunistic infection in individuals with acquired immunodeficiency syndrome (AIDS).
- Definitive diagnosis relies on the microscopic identification of Pneumocystis carinii in patient samples.
- Rapid and accessible diagnostic methods are crucial for timely treatment initiation.
Purpose of the Study:
- To compare the efficacy of Giemsa, Toluidine blue O, and methenamine silver nitrate staining methods for diagnosing Pneumocystis carinii pneumonia.
- To evaluate the ease of organism recognition, speed, and cost-effectiveness of each staining technique.
Main Methods:
- Bronchoalveolar lavage fluids from 35 AIDS patients suspected of Pneumocystis pneumonia were analyzed.
- Three staining techniques were employed: Giemsa, Toluidine blue O, and methenamine silver nitrate.
- The presence, developmental stages, and contrast of Pneumocystis carinii were assessed for each method.
Main Results:
- Giemsa stain identified Pneumocystis carinii in 18 cases (51.4%), visualizing cysts, sporozoites, and trophozoites, but with suboptimal contrast.
- Toluidine blue O and methenamine silver nitrate stains detected the organism in 21 cases (60%) each, offering excellent contrast for cysts but not revealing internal structures or trophozoites.
- Methenamine silver nitrate, while effective, may be limited by cost in resource-constrained settings.
Conclusions:
- Toluidine blue O is recommended as a rapid initial stain for easy recognition of Pneumocystis carinii cyst clusters.
- Giemsa stain can be used subsequently for identifying sporozoites and trophozoites when detailed morphology is required.
- The choice of staining method should consider diagnostic accuracy, speed, cost, and the specific diagnostic information needed.
