Staphylococcus epidermidis

Record number: 
Adverse Occurrence type: 
MPHO Type: 
Estimated frequency: 
Tranmission of a bacterial infection is rare (0.4% or likely even less)
Time to detection: 
3 - 14 days
Alerting signals, symptoms, evidence of occurrence: 
This study of culture results of 469 donor cornealscleral rims correlated positive findings with clinical outcomes. 16.8% were positive, 2/3 of these were Staphylocuccus epidermidis, and 11% of these streptococcus spp.. When both mated pair of cornea were contaminated, > 90% had different bacteria on each of them. Only 9 (6% of 98) had the same on both. Seven recipients (1.5% of total transplants) had postop ocular infections, 6 with a corneal graft ulcer and one with endophthalmitis. Two of those with corneal ulcers, (0.4% of the total transplants) had the same organism cultured (Staphylococcus epidermidis) from the ulcer and the donor cornealscleral rim, suggesting possible  transmission. Initially developing a corneal ulcer 3-14 days postop (mean 5 days)
Demonstration of imputability or root cause: 
Level 2. Possible, but unlikely. These 2 cases had Staph epi found in the corneal ulcer and on the donor tissue, suggesting a causative link. Usually, causation is considered when the bacteria is rare, with a very low prevalence or having a high virulence and is found in donor and recipient infection. In this case, the donor tissue and recipient infection show Staph epi, a bacterium commonly found in the environment (and the most common bacterium contaminating corneas not causing infection in recipients) and of low virulence. Generally we do not assume causation by donor-to-recipient transmission because the bacterium could easily have been aquired in the hospital during or after surgery and because the bacterium has low virulence, rarely causing disease when present.