The Queensland Bone Bank, Brisbane, Queensland, Australia.
J Ind Microbiol Biotechnol. 2011 Aug;38(8):1127-32. doi: 10.1007/s10295-011-0982-z. Epub 2011 May 21.
Sterility testing is the final, and critical, step in quality control of tissue banking. It informs the decision whether to release the tissue allografts for clinical use, or not. The most common method for sterility testing of structural bone and tendon allografts is to swab using cotton tip streaks. This method provides low recovery efficiency; and therefore may pass allografts with low bioburden, providing false negatives. Our pilot data revealed organism recovery efficiencies of 60, 30 and 100% from cotton swab, membrane filtration and sponge swaps, respectively. Our aim was to develop a high sensitivity sterility test for structural bone and tendon allografts using a sponge sampling method. Eighty-one bone and tendon allograft samples were inoculated with organism suspensions (10(2) or less organisms per 0.1 mL) of Clostridium sporogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Bacillus subtilis, Aspergillus niger, Staphylococcus epidermidis and Micrococcus spp. Nasco sponges (4 × 8 cm) were used to aseptically sample the whole surface of allograft samples. The sponges were cut in half and cultured in either tryptone soya or fluid thioglycollate broths for 14 days. Positive culture samples were further examined for microbial morphology. The results showed that the sensitivity of the method, and negative predictive value, is 100% for all inoculated organisms incubated with thioglycollate. We conclude that this sponge sampling method should be applied as the standard for sterility testing of structural bone and tendon allografts.
无菌检测是组织库质量控制的最后也是关键的一步。它决定了是否放行组织同种异体移植物用于临床。结构骨和肌腱同种异体移植物无菌检测最常用的方法是使用棉签划线。这种方法回收率低，可能会放行低生物负荷的同种异体移植物，导致假阴性。我们的初步数据显示，从棉签、膜过滤和海绵拭子中分别回收了 60%、30%和 100%的微生物。我们的目的是开发一种高灵敏度的结构骨和肌腱同种异体移植物无菌检测方法，采用海绵采样法。将 81 个骨和肌腱同种异体移植物样本接种到梭状芽胞杆菌、金黄色葡萄球菌、铜绿假单胞菌、白色念珠菌、枯草芽孢杆菌、黑曲霉、表皮葡萄球菌和微球菌的悬液中（每个 0.1ml 中少于 10(2)个微生物）。使用 Nasco 海绵（4×8cm）无菌采样同种异体移植物样本的整个表面。将海绵切成两半，分别在胰蛋白胨大豆肉汤或液体硫代乙醇酸盐肉汤中培养 14 天。对阳性培养样本进一步检查微生物形态。结果表明，该方法的灵敏度和阴性预测值在培养硫代乙醇酸盐的所有接种微生物中均为 100%。我们得出结论，这种海绵采样方法应作为结构骨和肌腱同种异体移植物无菌检测的标准方法。
