6 research outputs found
Evaluation of a microbiological screening and acceptance procedure for cryopreserved skin allografts based on 14Â day cultures
Viable donor skin is still considered the gold standard for the temporary covering of burns. Since 1985, the Brussels military skin bank supplies cryopreserved viable cadaveric skin for therapeutic use. Unfortunately, viable skin can not be sterilised, which increases the risk of disease transmission. On the other hand, every effort should be made to ensure that the largest possible part of the donated skin is processed into high-performance grafts. Cryopreserved skin allografts that fail bacterial or fungal screening are reworked into âsterileâ non-viable glycerolised skin allografts. The transposition of the European Human Cell and Tissue Directives into Belgian Law has prompted us to install a pragmatic microbiological screening and acceptance procedure, which is based on 14Â day enrichment broth cultures of finished product samples and treats the complex issues of âacceptable bioburdenâ and âabsence of objectionable organismsâ. In this paper we evaluate this procedure applied on 148 skin donations. An incubation time of 14Â days allowed for the detection of an additional 16.9% (25/148) of contaminated skin compared to our classic 3Â day incubation protocol and consequently increased the share of non-viable glycerolised skin with 8.4%. Importantly, 24% of these slow-growing microorganisms were considered to be potentially pathogenic. In addition, we raise the issue of ârepresentative samplingâ of heterogeneously contaminated skin. In summary, we feel that our present microbiological testing and acceptance procedure assures adequate patient safety and skin availability. The question remains, however, whether the supposed increased safety of our skin grafts outweighs the reduced overall clinical performance and the increase in work load and costs
Glycerol treatment as recovery procedure for cryopreserved human skin allografts positive for bacteria and fungi
Human donor skin allografts are suitable and much used temporary biological (burn) wound dressings. They prepare the excised wound bed for final autografting and form an excellent substrate for revascularisation and for the formation of granulation tissue. Two preservation methods, glycerol preservation and cryopreservation, are commonly used by tissue banks for the long-term storage of skin grafts. The burn surgeons of the Queen Astrid Military Hospital preferentially use partly viable cryopreserved skin allografts. After mandatory 14-day bacterial and mycological culture, however, approximately 15% of the cryopreserved skin allografts cannot be released from quarantine because of positive culture. To maximize the use of our scarce and precious donor skin, we developed a glycerolisation-based recovery method for these culture positive cryopreserved allografts. The inactivation and preservation method, described in this paper, allowed for an efficient inactivation of the colonising bacteria and fungi, with the exception of spore-formers, and did not influence the structural and functional aspects of the skin allografts