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Updated: Aug 14, 2026
Biolistic Transformation of a Fluorescent Tagged Gene into the Opportunistic Fungal Pathogen Cryptococcus neoformans
Published on: March 19, 2015
Assessment of a PCR technique for the detection and identification of Cryptococcus neoformans
C Prariyachatigul1, A Chaiprasert, V Meevootisom
1Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand.
Abstract:
The 18S ribosomal RNA gene of Cryptococcus neoformans was amplified by polymerase chain reaction (PCR). The primers CPL1 and CPR4 were tested for their ability to amplify DNA from 30 strains of C. neoformans and 27 specimens of cerebrospinal fluid (CSF) from patients with cryptococcal meningitis. A 343 bp product was obtained and its specificity confirmed by Southern hybridization with an internal sequence (INSR4) probe. The sensitivity was 100 fg by Southern analysis and 1 pg using the PCR. Neither human nor a variety of other fungal and bacterial strains (n = 78) gave an amplified product. This PCR method can detect as few as 5 cells ml-1 of C. neoformans in spiked-CSF following a simple processing procedure. The developed system of PCR was more sensitive than the culture method and revealed a very high specificity. The PCR was easy to perform and needed only 4 h for all processes from receiving the CSF to detection of a specific DNA band after agarose gel electrophoresis. This would provide another rapid laboratory method for the diagnosis of cryptococcal meningitis.
Insights
A new polymerase chain reaction (PCR) method rapidly and specifically detects Cryptococcus neoformans DNA in cerebrospinal fluid (CSF). This sensitive technique offers a faster diagnostic tool for cryptococcal meningitis.
Area of Science:
- Microbiology
- Molecular Biology
- Medical Diagnostics
Background:
- Cryptococcal meningitis is a serious fungal infection, particularly in immunocompromised individuals.
- Current diagnostic methods for cryptococcal meningitis can be slow and lack sensitivity.
- Rapid and accurate detection of Cryptococcus neoformans is crucial for timely treatment.
Purpose of the Study:
- To develop and evaluate a highly sensitive and specific polymerase chain reaction (PCR) assay for detecting Cryptococcus neoformans DNA.
- To assess the utility of this PCR method for diagnosing cryptococcal meningitis directly from cerebrospinal fluid (CSF).
Main Methods:
- Amplification of the 18S ribosomal RNA gene of Cryptococcus neoformans using specific primers (CPL1 and CPR4).
- Testing the assay's specificity against human DNA, various fungal, and bacterial strains.
- Determining the assay's sensitivity using Southern analysis and PCR.
- Evaluating the detection limit of the PCR method in spiked CSF samples.
Main Results:
- A specific 343 bp DNA product was consistently amplified from 30 strains of C. neoformans.
- The PCR assay demonstrated high specificity, with no amplification from other microbial or human DNA.
- The method achieved a sensitivity of 1 pg DNA by PCR and could detect as few as 5 cells/mL of C. neoformans in CSF.
- The entire process, from CSF receipt to DNA detection, required only 4 hours.
Conclusions:
- The developed PCR assay is a rapid, sensitive, and specific method for detecting Cryptococcus neoformans.
- This technique offers a significant improvement over traditional culture methods for diagnosing cryptococcal meningitis.
- The PCR assay provides a valuable new laboratory tool for the prompt diagnosis of cryptococcal meningitis.
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