Validation of the sterilization procedure of allogeneic avital bone transplants using peracetic acid-ethanol

Different procedures are available to inactivate bacteria and fungi, Includ ing their spores, as well as viruses In human bone transplants. The most ef ficient methods are considered to be gamma irradiation and thermal inactiva tion as well as chemical sterilization methods like the peracetic acid-etha nol treatment (PES). Following national and international standards or draf t standards, the antimicrobial effectiveness of this procedure was evaluate d. Due to the standardizable size as well as the clinical relevance, defatt ed human spongiosa cuboids (15x15x15 mm)served as model system. After treat ment with PES for 2 and 4 hours, respectively, the titre of living micro-or ganisms was determined in the supernatant and the cuboid. A reduction in the titre of viable micro-organisms below the detection leve l (reduction factor >5 log(10)) was already achieved after an incubation ti me of 2 hours (Staphylococcus aureus, Enterococcus faecium, Pseudomonas aer uginosa, Bacillus subtilis, Clostridium sporogenes, Mycobacterium terrae, C andida albicans as well as spores of Bacillus subtilis). No viable micro-or ganisms could be detected in any of the PES-treated test cuboids. Spores of Aspergillus niger were also completely inactivated. The PES procedure prov ed to be a reliable method for the sterilization of human bone transplants derived from spongiosa. (C) 2001 The International Association for Biologic als.