Abstract
Purpose Ralstonia insidiosa is a waterborne bacteria that can survive and grow in various water sources and is considered as emerging opportunistic pathogen. Recently, for the first time in our tissue bank, we identified three cases of corneal contamination with R. insidiosa. Here we present the results of the root cause analysis of corneal contamination in these cases.
Methods Corneoscleral rims were excised in donor hospitals. Prior to procurement, corneas were decontaminated using standard procedure. For cornea preservation the tissue culture method was used. Medium for corneal storage (Alchimia) was routinely thawed in the refrigerator overnight. Exceptionally, when corneas were prepared for emergency, the medium was thawed in the water bath. Three microbiological controls during cornea preservation were performed. During every processing step microbiology control of the environment and staff was routinely performed.
Results In a period of four months, 141 corneas were procured, out of them, 90 were stored in the tissue culture and microbiologically tested. Three (3,3%) corneas were contaminated with R. insidiosa. In two cases contaminations were detected in first microbiology control and one in the transport medium. Environmental and staff microbiology controls during tissue processing of contaminated corneas were sterile.
Contaminated corneas were procured in different donor hospitals. We didn’t find correlation between donor infection and cornea contamination. Two out of the three medium of contaminated cornea were thawed in the water bath. In parallel, microbiological testing of 12 reagents, including all serial numbers used during procurement and processing of contaminated cornea was performed. Critical process steps were defined and 29 microbiology swabs of the critical equipment used were perfomed (water bath where medium for corneal storage is thawed in emergency cases, refrigerator and incubator). All reagents used were sterile. Bacteria R. insidiosa was detected in the water bath.
Additional disinfection of the water bath was performed, microbiological testing afterwards was sterile. Clinical follow-up of the patient transplated before the contamination was detected did not show transmission of the infection.
Conclusions The root cause analysis showed that the source of the corneal contamination was in the water bath. After this event, we changed the procedure for thawing the medium for emergency transplants and water bath is no longer used.
