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Polymerase chain reaction in the diagnosis of Aspergillus endophthalmitis
A R Anand1, H N Madhavan, N V Sudha
1Microbiology Research Centre, Vision Research Foundation, Sankara Nethralaya, Chennai, India.
Background & Objectives:
Aspergillus endophthalmitis is the commonest type of vision threatening fungal endophthalmitis encountered in India. Since conventional methods lack sensitivity, we evaluated polymerase chain reaction (PCR) against the conventional mycological methods in the diagnosis of Aspergillus endophthalmitis.
Methods:
Twenty-seven intraocular specimens from 22 patients with suspected fungal endophthalmitis (proven as non-bacterial origin) and 10 patients with non-infective intraocular disorders (controls) were tested. The intraocular specimens from these patients were subjected to the conventional methods, viz., microscopy and culture for growth of fungi, as well as PCR for the detection and differentiation of species of Aspergillus.
Results:
None of the controls were positive by microscopy, culture or PCR. Among the 27 test samples, 4 were positive by culture for Aspergillus species, these were also positive by PCR. In addition, PCR detected and identified Aspergillus species in 2 culture negative specimens. The average time required for culture and identification of Aspergillus was 10 days, whereas PCR needed only 24 h.
Interpretation & Conclusion:
This study indicates that PCR was not only a more sensitive, but also a rapid diagnostic tool compared to the conventional mycological methods in the diagnosis of Aspergillus endophthalmitis.
Insights
Polymerase chain reaction (PCR) offers a more sensitive and rapid diagnosis for Aspergillus endophthalmitis compared to traditional methods. This advancement aids in quicker identification and treatment of this vision-threatening fungal infection.
Area of Science:
- Ophthalmology
- Medical Mycology
- Molecular Diagnostics
Background:
- Aspergillus endophthalmitis is a leading cause of vision loss due to fungal infections in India.
- Conventional diagnostic methods for fungal endophthalmitis, such as microscopy and culture, often lack sensitivity and require significant time for results.
- There is a need for more accurate and rapid diagnostic tools to manage Aspergillus endophthalmitis effectively.
Purpose of the Study:
- To evaluate the diagnostic performance of polymerase chain reaction (PCR) for Aspergillus endophthalmitis.
- To compare the sensitivity and speed of PCR with conventional mycological methods (microscopy and culture).
- To assess the utility of PCR in detecting and differentiating Aspergillus species in intraocular specimens.
Main Methods:
- Intraocular specimens from 22 patients with suspected fungal endophthalmitis and 10 controls were analyzed.
- Conventional methods included microscopy and fungal culture.
- Polymerase chain reaction (PCR) was employed for the detection and species identification of Aspergillus.
Main Results:
- No positive results were observed in the control group using any method.
- Culture identified Aspergillus in 4 samples, all of which were also positive by PCR.
- PCR detected Aspergillus in 2 additional culture-negative samples, demonstrating higher sensitivity.
- PCR provided results within 24 hours, significantly faster than the 10 days required for culture.
Conclusions:
- Polymerase chain reaction (PCR) is a more sensitive diagnostic tool for Aspergillus endophthalmitis than conventional mycological methods.
- PCR offers a significantly faster diagnostic turnaround time, enabling prompt clinical management.
- The study highlights PCR as a valuable rapid diagnostic tool for Aspergillus endophthalmitis.