Biosafety Unit, Health Protection Agency, Microbiological Services Division, Porton Down, Salisbury, United Kingdom.
Appl Environ Microbiol. 2012 Jun;78(12):4169-74. doi: 10.1128/AEM.07948-11. Epub 2012 Apr 6.
The currently used microbial decontamination method for spacecraft and components uses dry-heat microbial reduction at temperatures of >110°C for extended periods to prevent the contamination of extraplanetary destinations. This process is effective and reproducible, but it is also long and costly and precludes the use of heat-labile materials. The need for an alternative to dry-heat microbial reduction has been identified by space agencies. Investigations assessing the biological efficacy of two gaseous decontamination technologies, vapor hydrogen peroxide (Steris) and chlorine dioxide (ClorDiSys), were undertaken in a 20-m(3) exposure chamber. Five spore-forming Bacillus spp. were exposed on stainless steel coupons to vaporized hydrogen peroxide and chlorine dioxide gas. Exposure for 20 min to vapor hydrogen peroxide resulted in 6- and 5-log reductions in the recovery of Bacillus atrophaeus and Geobacillus stearothermophilus, respectively. However, in comparison, chlorine dioxide required an exposure period of 60 min to reduce both B. atrophaeus and G. stearothermophilus by 5 logs. Of the three other Bacillus spp. tested, Bacillus thuringiensis proved the most resistant to hydrogen peroxide and chlorine dioxide with D values of 175.4 s and 6.6 h, respectively. Both low-temperature decontamination technologies proved effective at reducing the Bacillus spp. tested within the exposure ranges by over 5 logs, with the exception of B. thuringiensis, which was more resistant to both technologies. These results indicate that a review of the indicator organism choice and loading could provide a more appropriate and realistic challenge for the sterilization procedures used in the space industry.
目前用于航天器和部件的微生物去污方法是使用干热微生物减少法，在 >110°C 的温度下延长时间，以防止对行星际目的地的污染。该过程有效且可重复，但也耗时且昂贵，并排除了对热不稳定材料的使用。太空机构已经确定需要替代干热微生物减少的方法。评估两种气态去污技术（汽化过氧化氢（Steris）和二氧化氯（ClorDiSys））的生物功效的研究在 20m³暴露室中进行。将五个形成孢子的芽孢杆菌种暴露在不锈钢优惠券上，暴露于汽化过氧化氢和二氧化氯气体中。暴露于汽化过氧化氢 20 分钟，分别导致萎缩芽孢杆菌和嗜热脂肪芽孢杆菌的恢复减少 6-和 5 个对数。然而，相比之下，二氧化氯需要 60 分钟的暴露时间才能将萎缩芽孢杆菌和嗜热脂肪芽孢杆菌减少 5 个对数。在所测试的三个其他芽孢杆菌中，苏云金芽孢杆菌对过氧化氢和二氧化氯最具抵抗力，D 值分别为 175.4 秒和 6.6 小时。这两种低温去污技术都能有效地在暴露范围内将测试的芽孢杆菌减少超过 5 个对数，除了苏云金芽孢杆菌，它对两种技术都更具抵抗力。这些结果表明，审查指示生物的选择和加载可以为太空工业中使用的灭菌程序提供更合适和现实的挑战。
