アイバンク提供眼の眼球保存液におけるMRSA汚染の検討

Contamination of preservative medium for keratoplasty by methicillin-resistant Staphylococcus aureus

要約　目的：角膜移植に用いる提供眼のメシチリン耐性黄色ブドウ球菌（MRSA）陽性率と背景因子の報告。

対象と方法：2015年までの8年間に順天堂医院で強角膜片を作製した646眼の眼球保存液を対象として細菌培養を行い，MRSAによる汚染の有無を検索した。提供眼の背景因子として，提供者の年齢，性別，死因，眼内レンズの使用の有無，死亡から眼球摘出または強角膜片作製までの時間，角膜内皮細胞密度などを多変量解析で検討した。

結果：646検体中391検体（60.5％）で細菌が培養され，うちMRSAは60検体（9.3％）から検出された。MRSA陽性群での提供者の平均年齢は85.1歳で，陰性群での75.6歳より有意に高く（p＜0.001），死亡から強角膜片作製までの時間が有意に長く（p＜0.007），角膜内皮細胞密度が有意に低かった（p＜0.001）。性別，死因，眼内レンズの使用の有無は，両群間に差がなかった。

結論：角膜移植用の眼球保存液のMRSAによる汚染は，高齢者からの提供眼球と，死亡から強角膜片作製までの時間が長いときに，頻度が高かった。

Abstract　Purpose：To report contamination of preservative solution for keratoplasty by methicillin-resistant Staphylococcus aureus（MRSA）.

Material and Method：This retrospective study was made on 646 eyes that were donated for keratoplasty during 8 years through 2015 and that were processed into corneoscleral specimen at the Juntendo Hospital. The preservative solution was cultured for bacterial contamination. Incidence of MRSA was analyzed regarding age and gender of the donor, cause of death, duration between death and enucleation, corneal endothelial density among others.

Results：Bacterial culture was positive in 391 out of 646 specimens（60.5％）including MRSA in 60 specimens（9.3％）. Contamination by MRSA was significantly higher from donors of advanced age（p＜0.001）, and after longer duration between death and processing of corneoscleral specimen（p＜0.007）. No difference was present between MRSA-positive and-negative groups regarding gender, cause of death, or use of intraocular lens.

Conclusion：Contamination of preservative solution for donor cornea was more frequent when the donor was advanced in age and after longer duration between death and processing of corneoscleral specimen.