Evaluation of lectin staining in the diagnosis of fungal keratitis in an experimental rabbit model.

PURPOSE

To assess the sensitivity, specificity, and reliability of peroxidase labeled lectin staining in the diagnosis of fungal keratitis in an experimental rabbit model.

METHODS

Fungal keratitis by Candida albicans, Aspergillus fumigatus, and Fusarium solani was induced in rabbits. WGA-peroxidase staining of 660 corneal sections was performed. Fungal staining was evaluated independently by two observers. The test sensitivity, specificity, and reliability indexes were calculated.

RESULTS

The sensitivity of the lectin staining test for Candida albicans was 100% (95% CI: 93.51-100.00), and specificity was 100% (95% CI: 93.51-100.00). The sensitivity of the test for Aspergillus fumigatus was 96.36% (95% CI: 86.46-99.35), and specificity was 100% (95% CI: 93.51-100.00). The sensitivity of the test for Fusarium solani was 96.36% (95% CI: 86.46-99.35) and specificity was 96.15% (95% CI: 85.74-99.31). There was also a high degree of test-retest and inter-rater concordance for all three fungi tested. The test-retest k reliability indexes were 0.9455, 0.9636, and 0.8879, for Candida albicans, Aspergillus fumigatus, and Fusarium solani, respectively. The inter-rater k reliability indexes were 0.9636, 0.9818, and 0.9252, for Candida albicans, Aspergillus fumigatus, and Fusarium solani, respectively.

CONCLUSIONS

WGA-peroxidase staining is a very sensitive, specific, and reliable test for the identification of fungi in an experimental rabbit model of fungal keratitis.