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Real time quantitative PCR and RT--PCR for analysis of Pneumocystis carinii hominis
K Kaiser1, M Rabodonirina, S Picot
1Laboratoire de Parasitologie, Mycologie Médicale et Maladies Tropicales--Hospices Civils de Lyon-EA 3087-Université C. Bernard Lyon I-8, avenue Rockefeller 69373, Lyon Cedex 08, France. kaiser@rockefeller.univ-lyon1.fr
Abstract:
Pneumocystis carinii hominis is a common cause of pneumonia in immunocompromised patients and particularly in those infected by HIV. Giemsa- and Gomori--Grocott-stained smears are widely used for detection and quantification of this opportunistic fungus obtained from biological samples or from in vitro culture. But these methods are fastidious and time-consuming. Thus, instead of performing a count of organisms, we focused our attention on the level of specific DNA by a quantitative PCR technique. This procedure has the advantage of greater precision and more objectivity. To verify the presence of organisms, quantitative RT--PCR based on DHFR and a cell cycle mRNA have been developed. In this current study, we present a detailed description of these methods and their applications for analysis of P. carinii hominis.
Insights
Quantitative PCR offers a precise and objective method for detecting Pneumocystis jirovecii pneumonia (PCP) DNA, improving upon traditional, time-consuming smear techniques in immunocompromised patients.
Area of Science:
- Medical Mycology
- Molecular Diagnostics
- Infectious Diseases
Background:
- Pneumocystis jirovecii pneumonia (PCP) is a significant opportunistic infection in immunocompromised individuals, especially those with HIV.
- Traditional diagnostic methods like Giemsa and Gomori-Grocott staining are labor-intensive and subjective.
- There is a need for more accurate and efficient diagnostic tools for PCP detection and quantification.
Purpose of the Study:
- To develop and describe quantitative PCR (qPCR) methods for detecting Pneumocystis jirovecii.
- To offer a more precise and objective alternative to conventional staining techniques.
- To present the application of these molecular methods for P. jirovecii analysis.
Main Methods:
- Development of quantitative reverse transcription PCR (RT-PCR) assays.
- Targeting dihydrofolate reductase (DHFR) and a cell cycle mRNA for detection.
- Application of qPCR for organism quantification in biological samples and in vitro cultures.
Main Results:
- Quantitative PCR provides greater precision and objectivity compared to traditional smear methods.
- The developed RT-PCR assays effectively verify the presence of Pneumocystis jirovecii.
- These molecular techniques offer a robust approach for P. jirovecii analysis.
Conclusions:
- Quantitative PCR is a superior diagnostic tool for Pneumocystis jirovecii detection and quantification.
- Molecular methods offer significant advantages in speed, accuracy, and objectivity for PCP diagnosis.
- The described qPCR techniques are valuable for clinical and research applications in managing PCP.