[Positive corneoscleral rim culture in penetrating keratoplasty at the Porto Alegre Clinical Hospital]

Abstract

Purpose: To determine the incidence of positive corneoscleral rim cultures preserved in Optisol GS medium, to identify pathogens involved and possible recipient eye infection.

Methods: A hundred sixty-three corneoscleral rim cultures penetrating keratoplasties performed from January 2001 to January 2003 in the Hospital de Clínicas de Porto Alegre were reviewed. Enucleations and corneal storage were done as aseptic as possible and gentamicin 0.3% was instilled. Corneoscleral rim was divided into two segments, half was inoculated into Sabouraud broth and the other half into thioglycolate broth; inoculation into blood agar, chocolate agar and MacConkey agar was done later if necessary for pathogen identification. The receiver's eye data were reviewed.

Results: There were eleven positive cultures (6.7%) out of 163 evaluated corneoscleral rim cultures. Of these, four were Staphylococcus epidermidis, one was Staphylococcus aureus, one was Serratia sp., one was Pseudomonas aeruginosa and the other four were different subtypes of Candida (two Candida sp., one Candida albicans and one Candida parapapilosis). All pathogens were resistant to gentamicin. None of the eleven cases of positive corneoscleral rim cultures resulted in ocular infection at the receiver's eyes (six months follow-up).

Conclusions: We found low rates of positive corneoscleral rim cultures after penetrating keratoplasty at the Porto Alegre Clinical Hospital. The most frequent involved pathogens were Staphylococcus sp and Candida sp. Although we did not identify any postoperative infection at the receiver's eyes, we recommend corneoscleral rim culture for guidance of postoperative infection, a rare but possible devastating ocular event.