Difficulties in demonstrating fungi in cornea culture medium

It is not always possible to prevent the growth of microorganisms in organ culture for cornea preservation, despite many prophylactic measures. It is especially difficult to prove the presence of fungi in the cultural medium. Materials and methods: A culture medium was examined for sterility after 8 days' storage of cornea in organ culture. To prove the presence of fungi a culture of Sabouraud 2% glucose-agar was prepared and its growth examined b y light microscopy. Results: After 8 days of preservation we noticed a color change in the cult ural medium and suspected contamination with fungi. Coagulase-negative Stap hylococci could be cultivated from the conjunctival smear obtained before p reparation of the cornea only Routine screening of microbiological contamin ation did not show any results. We were able to identify an Aspergillus spe cies only after preparing a special culture. The conjunctival smear as well as the cultural medium of the other eye of the same donor showed no contam ination. Conclusions: In spite of the fact that microbiological contamination can be seen macroscopially, it is difficult to prove the presence of a specific m icroorganism and even more so when dealing with fungus. Especially in these cases the incubation of the cornea in media might have an advantage becaus e contamination can be suspected by just looking at the medium. By excludin g these preparations from transplantation we can possibly prevent infection s, even when routine examinations show negative results.