Related Experiment Video
Updated: Jul 5, 2026
Combined Recombinase Polymerase Amplification CRISPR/Cas12a Assay for Detecting Fusarium oxysporum f. sp. cubense Tropical Race 4
Published on: November 14, 2025
Specific detection of fungal pathogens by 18S rRNA gene PCR in microbial keratitis
Zunaina Embong1, Wan Hazabbah Wan Hitam, Chan Yean Yean
1Department of Ophthalmology, School of Medical Sciences, Universiti Sains Malaysia, Malaysia. zunaina@yahoo.com
Background:
The sensitivity and specificity of 18S rRNA polymerase chain reaction (PCR) in the detection of fungal aetiology of microbial keratitis was determined in thirty patients with clinical diagnosis of microbial keratitis.
Methods:
Corneal scrapings from patients were used for Gram stain, culture and PCR analysis. PCR was performed with primer pairs targeted to the 18S rRNA gene. The result of the PCR was compared with conventional culture and Gram staining method. The PCR positive samples were identified by DNA sequencing of the internal transcribed spacer (ITS) region of the rRNA gene. Main outcome measures were sensitivity and specificity of PCR in the detection of fungus in corneal keratitis.
Results:
Combination of microscopy and culture gave a positive result in 11 of 30 samples of microbial keratitis. PCR detected 10 of 11 samples that were positive by conventional method. One of the 19 samples that was negative by conventional method was positive by PCR. Statistical analysis revealed that the PCR to have a sensitivity of 90.9% and specificity of 94.7% in the detection of a fungal aetiology in microbial keratitis.
Conclusion:
PCR is a rapid, sensitive and useful method to detect fungal aetiology in microbial keratitis.
Insights
Polymerase chain reaction (PCR) offers a sensitive and specific method for detecting fungal causes of microbial keratitis. This molecular technique aids in diagnosing fungal eye infections more effectively than traditional methods.
Area of Science:
- Ophthalmology
- Medical Mycology
- Molecular Biology
Background:
- Microbial keratitis is an eye infection that can lead to vision loss.
- Fungal keratitis is a significant cause of microbial keratitis, particularly in certain geographic regions.
- Accurate and rapid diagnosis is crucial for effective treatment of fungal keratitis.
Purpose of the Study:
- To determine the sensitivity and specificity of 18S ribosomal RNA (rRNA) polymerase chain reaction (PCR) for detecting fungal keratitis.
- To compare the diagnostic performance of PCR with conventional methods like Gram staining and culture.
- To evaluate the utility of PCR as a diagnostic tool for fungal aetiology in microbial keratitis.
Main Methods:
- Corneal scrapings from 30 patients with microbial keratitis were analyzed.
- Conventional methods included Gram stain and fungal culture.
- PCR analysis utilized primers targeting the 18S rRNA gene, with positive results confirmed by DNA sequencing of the internal transcribed spacer (ITS) region.
Main Results:
- Conventional methods (microscopy and culture) identified fungal aetiology in 11 out of 30 samples.
- PCR detected 10 of these 11 positive samples and identified one additional positive case missed by conventional methods.
- PCR demonstrated a sensitivity of 90.9% and a specificity of 94.7% for detecting fungal keratitis.
Conclusions:
- Polymerase chain reaction (PCR) is a highly sensitive and specific method for diagnosing fungal keratitis.
- PCR offers a rapid and effective alternative to conventional diagnostic techniques for fungal eye infections.
- The use of 18S rRNA gene targets in PCR enhances the detection capabilities for fungal pathogens in corneal infections.
