Laboratory Diagnosis of Postoperative Endophthalmitis: Comparison of Traditional Microbiological Procedures and Molecular Diagnostic Technique
Purpose
To investigate and compare molecular diagnostic technique with traditional microbiological procedures for diagnosis of postoperative endophthalmitis.
Methods
In this retrospective study between January, 2011 and December, 2013, 49 cases of presumed postoperative endophthalmitis were identified. Gram stain and culture was performed according to agreed protocols. Samples of vitreous were transported to the referenced molecular biology laboratory for polymerase chain reaction (PCR) testing.
Results
Of the 49 cases which presented with presumed postoperative endophthalmitis, 25 were classified as proven infective endophthalmitis with positive Gram stain, culture, or PCR. Twenty two patients were positive for all methods (9 cases of S. epidermidis, 4 cases of S. aureus and 9 cases of Pseudomonas sp); 2 cases were only PCR positive but negative by Gram stain or culture; and a single case was only smear and culture positive. Twenty four patients were negative by both microbiology and PCR testing. The organism isolated from culture and PCR agreed in 22 cases and were similar with smear examination before culture results in 17 cases. Sensitivity of PCR in this study is found to be 96% while that of grams stain is 92%.
Conclusion
Smear and culture is important to identify the organism initially to start the treatment. Molecular identification technique will confirm the result as well as the identification of the organism with a high sensitivity value.