Contamination of trypan blue with Burkholderia cepacia in a cornea bank.

OBJECTIVE: To describe Burkholderia cepacia contamination of a cornea bank and the measures taken to identify and eliminate the source of infection. METHODS: Cultures were performed to assess the extent and source of contamination, and pulsed-field gel electrophoresis was used for molecular typing. RESULTS: Routine surveillance cultures identified 5 contaminated corneas during a 10-day period. Additional cultures showed that 28 of 88 samples were positive for this organism. Environmental investigation showed that an open bottle of trypan blue used to assess corneal morphology was contaminated with the epidemic strain. CONCLUSION: Trypan blue played a major role in this contamination of corneas. This episode shows that microbial contamination can affect transplanted corneas despite ongoing culture surveillance and suggests that new methods may be needed to avoid this risk.

Bacterial contamination of a cornea tissue bank: implications for the safety of graft engineering.

PURPOSE: To analyze the difficulties involved in managing an episode of bacterial contamination in a cornea bank. We describe (1) the circumstances of bacterial contamination discovery, (2) the methods used to investigate the outbreak, (3) the corrective measures adopted, and (4) the method introduced to improve the reaction capacity in case of bacterial contamination. METHODS: All the samples collected were cultured in an attempt to identify the environmental reservoir of the contaminated epidemic clone. Bacteria were identified by Gram stain, oxidase test, and biochemical characteristics. The clonality of the strains was assessed by pulsed-field gel electrophoresis. RESULTS: The bacterial contamination was confirmed for 28 corneas, and 70 additional corneas were discarded. The source of the contamination was identified 17 days after the beginning of the episode. It consisted of a clonal bacterial strain that was found in trypan blue, the dye, used to examine all the tissues. The contaminating bacterium was Burkholderia cepacia, a well-known nosocomial pathogen. A total of 169 grafted corneas had been checked with the contaminated reagent. No cases of post-graft infection were recorded. CONCLUSION: Trypan blue played a major role in this outbreak. The mode and chronology of contamination remain unresolved. This exceptional event emphasizes the risk of bacterial contamination in tissue/cell banks, the necessity to improve methods for its prevention, and procedures to limit its consequences.