Current Mistaken Interpretation of Microbiological Data on Gas Plasma Sterilization
Current Mistaken Interpretation of Microbiological Data on Gas Plasma Sterilization
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目前对气体等离子体灭菌微生物数据的错误解释
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
H. Shintani
中科院分区：
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作者：
H. Shintani
即使当使用营养细胞时，在工程研究人员关于气体等离子体灭菌的论文中的存活曲线中也可以观察到拖尾现象。这表明甚至没有实现消毒。根据定义，灭菌是一种杀死所有类型微生物的过程，包括细菌孢子和营养细胞。相比之下，消毒只杀死营养细胞，不杀死细菌孢子。存活曲线的拖尾通常是由生物指示剂（BI）的聚集引起的，并且在没有关键知识、适当技术和保密知识的情况下制造自己的BI的工程研究人员经常发布非线性存活曲线以避免这种聚集。即使对于BI制造商来说，制备单层BI也是一项相当困难的任务，并且需要专有信息。因此，工程研究人员应购买市售BI。在市场上的BI中，我建议从默克公司购买BI，因为基于扫描电子显微镜（SEM）观察的结果发现结块最小。当观察到这种拖尾现象时，无法达到10-6的SAL，因此无法确定D值（十进制减少值），并且9或12 log减少的暴露时间仍然不确定。D值必须根据9 log或12 log减少存活曲线的直线确定，并且每个微生物只能有一个D值;每个微生物的D值永远不会超过一个。BI定义为对所用灭菌程序耐受性最强的微生物（通常为细菌孢子），因此如果BI被杀灭，则可以推测其他污染物（微生物）也被杀灭。因此，在灭菌确认研究和常规控制中使用BI是必不可少的。本文将考虑避免结块、拖尾现象并实现SAL 10-6的策略。
Even when using vegetative cells, a tailing phenomenon can be observed in survivor curves in engineering researcher’s papers on gas plasma sterilization. This indicates that even disinfection was not even achieved. By definition, sterilization is a process that kills all types of microorganisms including bacterial spores and vegetative cells. In contrast, disinfection kills only vegetative cells and does not kill bacterial spores. Tailing of a survivor curve is often caused by clumping of the biological indicator (BI), and engineering researchers who make their own BI without critical knowledge, appropriate techniques and confidential know-how to avoid such clumping frequently publish nonlinear survivor curves. Preparation of a monolayer of BI is quite a difficult task even for BI manufacturers and it requires proprietary information. Therefore, engineering researchers should purchase commercially available BI. Among the BIs on the market, I recommend purchasing BI from Merck Co., as clumping was found to be minimal based on results of scanning electron microscopy (SEM) observation. When such a tailing phenomenon is observed, a SAL of 10-6 cannot be attained, and therefore no D value (decimal reduction value) can be determined and the exposure time for a 9 or 12 log reduction remains undefined. The D value must be determined from the straight line of a 9 log or 12 log reduction survivor curve, and there can only be one D value per microorganism; there is never more than one D value per one microorganism. The BI is defined as the most tolerant microorganism (typically bacterial spores) to the sterilization procedure being used, so if the BI is killed, then other contaminants (microorganisms) can be speculated to also be killed. Therefore, the use of a BI is essential in sterilization validation studies and routine control. Strategies to avoid clumping, tailing phenomena and to attain a SAL of 10-6 will be considered in this article.