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RT-PCR Testing of Organ Culture Medium for Corneal Storage Fails to Detect SARS-CoV-2 Infection Due to Lack of Viral
Lisa Müller1, Philipp Niklas Ostermann1, Heiner Schaal1
1Institute of Virology, Medical Faculty, Heinrich-Heine-University of Düsseldorf, 40225 Düsseldorf, Germany.
Abstract:
Concerns of possible transmission of SARS-CoV-2 from donors to patients by corneal transplantation have caused a decline in corneal transplantations. Graft culture media are routinely tested for infectious risks, but it is unclear whether this constitutes a viable means to avoid transmitting SARS-CoV-2 via keratoplasty. We found that SARS-CoV-2 RNA was not present in the medium after seven days of organ culture of corneas from donors (n = 4), who were SARS-CoV-2-positive upon tissue procurement. These medium samples showed no presence of viral RNA. To pursue this question under controlled conditions and further exclude the possibility of productive infection in corneal grafts, we inoculated corneoscleral discs from healthy donors (n = 8) with infectious SARS-CoV-2 and performed PCR testing of the culture medium at various time points. After seven days of culture, we also tested for SARS-CoV-2 RNA within the inoculated corneal tissue. The medium from tissue samples inoculated with SARS-CoV-2 showed no increase in viral RNA, which may indicate lack of viral replication in these corneal grafts. SARS-CoV-2-RNA was, however, detected on or in corneal tissue seven days after inoculation. Our data suggest that corneal grafts may not be permissive for replication of SARS-CoV-2 and demonstrates that PCR testing of culture media cannot safely exclude that tissue has been exposed to SARS-CoV-2. It also demonstrates the difficulty to differentiate between virus adherence and virus replication by PCR testing in SARS-CoV-2 exposed tissue.
Insights
SARS-CoV-2 RNA was not detected in corneal graft culture media, but was present in the tissue. This suggests corneal grafts may not replicate the virus, but media testing alone cannot rule out exposure.
Area of Science:
- Virology
- Ophthalmology
- Infectious Diseases
Background:
- Corneal transplantation safety concerns due to SARS-CoV-2 transmission.
- Routine testing of graft culture media for infectious agents is standard practice.
- Uncertainty exists regarding the efficacy of current media testing to detect SARS-CoV-2 in corneal grafts.
Purpose of the Study:
- To investigate the potential for SARS-CoV-2 transmission through corneal transplantation.
- To determine if SARS-CoV-2 can replicate within corneal grafts.
- To assess the reliability of corneal graft culture media testing for detecting SARS-CoV-2 exposure.
Main Methods:
- Analysis of corneal organ culture media from SARS-CoV-2 positive donors.
- Controlled inoculation of healthy donor corneoscleral discs with SARS-CoV-2.
- RT-PCR testing of culture media and corneal tissue at various time points, including seven days post-inoculation.
Main Results:
- SARS-CoV-2 RNA was undetectable in the culture medium of corneas from naturally infected donors.
- Inoculated corneal tissue showed no evidence of viral RNA increase in the culture medium after seven days.
- SARS-CoV-2 RNA was detected on or within the corneal tissue seven days post-inoculation.
Conclusions:
- Corneal grafts appear non-permissive to SARS-CoV-2 replication.
- PCR testing of corneal graft culture media is insufficient to rule out SARS-CoV-2 exposure.
- Distinguishing between viral adherence and replication in exposed corneal tissue via PCR is challenging.
