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[Difficulties of fungus detection in corneal culture medium]
G Jendral1, F Wilhelm, H Bernhardt
1Augenklinik, Ernst-Moritz-Arndt-Universität Greifswald.
Unlabelled:
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 by light microscopy.
Results:
After 8 days of preservation we noticed a color change in the cultural medium and suspected contamination with fungi. Coagulase-negative Staphylococci could be cultivated from the conjunctival smear obtained before preparation of the cornea only. Routine screening of microbiological contamination did not show any results. We were able to identify an Aspergillus species 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 contamination.
Conclusions:
In spite of the fact that microbiological contamination can be seen macroscopically, it is difficult to prove the presence of a specific microorganism and even more so when dealing with fungus. Especially in these cases the incubation of the cornea in media might have an advantage because contamination can be suspected by just looking at the medium. By excluding these preparations from transplantation we can possibly prevent infections, even when routine examinations show negative results.
Insights
Detecting fungal contamination in cornea organ cultures is challenging, even with visual cues. Special cultures are crucial for identifying specific fungi like Aspergillus, preventing potential infections.
Area of Science:
- Ophthalmology
- Microbiology
- Organ Culture
Context:
- Preventing microbial contamination in cornea preservation is vital for successful transplantation.
- Standard prophylactic measures do not always prevent microorganism growth in organ culture.
Purpose:
- To investigate methods for detecting fungal contamination in cornea organ cultures.
- To highlight the difficulties in identifying specific microorganisms, especially fungi, in preserved corneas.
Summary:
- A case study involving cornea preservation revealed fungal contamination (Aspergillus species) despite initial negative routine screening.
- Macroscopic changes in the culture medium suggested contamination, but identification required specialized Sabouraud 2% glucose-agar cultures.
- Coagulase-negative Staphylococci were identified from a pre-cornea preparation, but not in the preserved cornea medium.
Impact:
- Emphasizes the need for enhanced detection methods beyond routine screening for fungal contamination in cornea preservation.
- Suggests that observing changes in culture media, even without positive routine results, can indicate contamination.
- Excluding contaminated cornea preparations, even those with initially negative routine tests, may prevent post-transplantation infections.