Purpose: To compare the frequency of positive rim cultures after penetrating keratoplasty using corneas preserved by hypothermic and organ culture storage. To evaluate the influence of standard procurement techniques on the frequency of microbial donor rim contamination.
Methods: Six hundred four donor corneas stored at 31°C and 214 at 4°C were studied. Microbiology studies were carried out during organ culture storage, and corneas with positive medium cultures were discarded. Frequency of postoperative positive rim cultures was related to the type of corneal storage and procurement technique used.
Results: Thirty-nine (6.4%) corneas with positive medium cultures were discarded during organ culture. Microbiology reports of 628 donor rims cultures from 671 (94%) consecutive transplants were reviewed. Positive rim cultures resulted in 24 (3.8%) cases. None of the patients developed endophthalmitis. The frequency of postoperative positive rim cultures was greater after hypothermic than organ culture storage, being 9.8% and 1.3%, respectively (χ2 = 24.9; P < 0.001). With organ culture storage, the frequency of positive rim cultures was 1.3% and 1.4% after enucleation and in situ corneal excision, respectively (χ2 = 0.03; P = 0.638). After hypothermic storage, positive rim cultures were found in 8% of the corneas procured using enucleation and 12% of the corneas excised in situ (χ2 = 0.829; P = 0.254).
Conclusions: Organ culture storage allows one to recognize and discard corneas with microbial contamination during storage. This method significantly reduces the frequency of postoperative positive rim cultures compared with hypothermic storage. Procurement methods do not influence the percentage of positive rim cultures.