Abstract
Abstract: :
Purpose: To evaluate the efficiency of microbiology culture and histopathology in the recovery of bacteria and fungi from post-penetrating keratoplasty corneal buttons. Method: The microbiology and pathology records of all patients treated for bacterial or fungal keratitis at The Bascom Palmer Eye Institute between January 1, 1996, and December 31, 2000, were reviewed. Fifty-six cases were found that underwent penetrating keratoplasty with both microbiology and pathology records. Results: Overall, microbiology cultures were positive in 35 cases (63%) and pathology was positive in 28 cases (50%). There were no findings in 15 cases (27%). The microbiology and pathology findings matched in 37 cases, for a 66% efficiency. Of the 19 cases (34%) with discordant results, microbiology was positive in 13 cases (68%) and pathology was positive in 6 cases (32%). Using culture results as the gold standard, pathology results were 63% specific and 54% sensitive. Pathology results had a positive predictive value of 79% and a negative predictive value of 41%. Using pathology findings as the gold standard, microbiology results were 79% sensitive and 71% specific. Microbiology results had a positive predictive value of 63% and a negative predictive value of 41%. Fungus was identified as the infectious agent in 28 cases (50%). Of the fungal cases, 23 cases (82%) had microbiology results and 24 cases (86%) had pathology findings. The efficiency of microbiology and pathology in identifying fungus was 68%. Microbiology and pathology differed in results in 9 cases (32%). Of the discordant cases, microbiology was positive in 4 cases (44%) and pathology was positive in 5 cases (56%). Bacteria was identified as the causative organism in 13 cases (23%). Of the bacterial cases, 12 cases (92%) had microbiology findings and 4 cases (31%) had pathology findings. The efficiency of microbiology and pathology in identifying bacteria was 23%. Microbiology and pathology differed in findings in 10 cases (77%). Of the discordant cases, microbiology was positive in 9 cases (90%) and pathology was positive in 1 case (10%). Conclusion: Microbiology and histopathology are complementary in identifying the etiology in corneal buttons after penetrating keratoplasty. Overall, microbiology is more sensitive and specific than pathology. The two modalities are similar in detecting fungus, with pathology more sensitive than microbiology. Microbiology is more sensitive in detecting bacterial organisms than pathology evaluation.