Polymerase chain reaction in the diagnosis of Aspergillus endophthalmitis

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.