ABSTRACT
Contaminated allograft donor tissue represents a potential source of infection unique to keratoplasty. We prospectively studied perilimbal cultures of drowning victims over 30 months to determine if the ocular surface flora of drowning victims was unique. Twenty-eight donor eyes were cultured from 14 drowning victims. Ninety-three percent of limbal cultures were positive for one or more organisms, compared to results of a previous study of surface contamination of donor globes in which 65% were found to be culture positive. Fifty-seven percent (16 of 28) of donor eyes grew at least one streptococcal species, while 46% (13 of 28) grew two or more streptococcal species. A previous study identified streptococcal species in 7.9% of perilimbal cultures from nondrowning donor eyes, which demonstrates the unique effect of drowning on the ocular flora. The incidence of gram-negative isolates was also markedly higher in drowning victims, compared to previous studies of donor globes. This prospective study has shown that the ocular surface flora of drowning victims harbors markedly increased numbers of streptococcal species as well as gram-negative organisms. These findings demand careful globe decontamination, and emphasize the need for appropriate antibiotic coverage in corneal storage media.
Subject(s)
Bacteria/isolation & purification , Cornea/microbiology , Drowning/microbiology , Adolescent , Adult , Bacteria/growth & development , Child , Humans , Keratoplasty, Penetrating , Microbiological Techniques , Prospective Studies , Tissue Donors , Transplantation, HomologousSubject(s)
Corneal Transplantation , Cyanides/poisoning , Tissue Donors , Adult , Cornea/pathology , Drug Contamination , Female , Humans , Male , Middle Aged , Postoperative Period , Visual AcuityABSTRACT
Excessive traction during excision of donor corneoscleral buttons can result in damage or death to corneal endothelial cells. This damage manifests as multiple peripheral and, less commonly, central striae or stretch marks that correspond to linear opacities at the level of the endothelium. The striae consist of parallel lines of degenerate endothelium, each line three to eight cells wide, and stain readily with trypan blue, which is indicative of cell damage or death. Light and electron microscopy demonstrates cell membrane lysis with abrupt demarcation between abnormal and normal endothelial cells. The number of these striae correlates with the degree of traction or stretch applied during corneoscleral excision. Careful slit-lamp biomicroscopy of corneoscleral buttons discloses endothelial striae in approximately 5% of specimens. Careful excisions of corneoscleral buttons are necessary to decrease the incidence and severity of endothelial striae.
Subject(s)
Cornea/pathology , Tissue Donors , Adolescent , Cornea/ultrastructure , Endothelium/pathology , Endothelium/ultrastructure , Eye Banks , Humans , Male , Staining and LabelingABSTRACT
Thirty-two corneas with scleral rims were cultured from the eyes of 17 cadavers that harbored systemic infection at the time of death. Twelve (71%) of 17 cadavers demonstrated corneal contamination from one or both corneas. Eleven (92%) of 12 donors with positive postmortem blood cultures had positive corneal cultures from at least one eye. Six of these 12 had the same organism isolated from both the blood and corneal tissue. Bacterial corneal cultures were negative in the five donors with negative postmortem blood cultures. Control cultures were obtained from 19 eyes of ten donors without evidence of infection at death. Four (21%) of 19 control eyes yielded Staphylococcus epidermidis. There was a significantly higher incidence of corneal contamination in donors who died with systemic infections. Eye banks should continue to screen donors carefully for documented or suspected sepsis in an effort to reduce the incidence of postkeratoplasty infections.
