The value of routine donor corneal rim cultures in penetrating keratoplasty
S. J. Wiffen, B. C. Weston, L. J. Maguire and W. M. Bourne
Department of Ophthalmology, Mayo Clinic, Rochester, Minn, USA.
OBJECTIVE: To investigate the value of donor corneal rim cultures performed
routinely at the time of penetrating keratoplasty. DESIGN: Retrospective
review of Mayo Clinic medical records for all corneal transplantations for
which donor rim cultures have been performed. MAIN OUTCOME MEASURES:
Frequency of positive cultures, occurrence of endophthalmitis within 2
months of undergoing surgery, action taken in response to the culture
results, and costs of cultures. RESULTS: Donor rim culture results were
available for 1078 of 1083 consecutive transplantations performed from 1981
to 1995. Three cases of endophthalmitis (0.28%) and 1 suture abscess
occurred. Rim cultures were negative in all of these cases. Action was
documented in response to positive cultures in 17 cases (8.1%). The
estimated average cost of routine rim cultures in 1994 was $137 per donor
cornea. Bacterial or fungal cultures were positive in 209 (19.4%) cases.
Two microorganisms were cultured simultaneously in 17 cases (1.6%) and 3 in
2 cases (0.2%). Staphylococcus coagulase-negative (130 cases [12.1%]), and
Streptococcus species, viridans group (23 cases [2.1%]), were the most
common isolates. Fifty-two (62.7%) of 83 coagulase-negative Staphylococcus
species isolates tested were resistant to gentamicin. There were more
positive cultures from corneas stored in Optisol (37/183 [20%]) than in
Optisol GS (16/144 [11%]) (P = .03). Fewer cultures were positive from live
donors (9/93 [10%]) compared with cadaveric donors (181/ 909 [20%]) (P =
.02). Positive cultures were more frequent for corneas excised in situ
(39/125 [31.2%]) than for those enucleated (152/851 [17.9%]) (P < .001).
CONCLUSIONS: Despite differences in rates of positive donor rim cultures
with different harvesting and storage techniques, for our practice, routine
donor corneal rim cultures had no predictive value for infective
complications of penetrating keratoplasty and, therefore, added an
unnecessary expense to the management of our patients.
