Skolnik Hannah E, Roberts Clifford R, Mabunga Don R, Lindstrom Krista E
J Am Assoc Lab Anim Sci. 2025 Jan 1;64(1):166-171. doi: 10.30802/AALAS-JAALAS-24-089.
To maintain rodent colonies free from harmful infectious agents, laboratory animal care programs frequently employ the use of sterilized caging and supplies. Sterilized caging is important for preventing the spread of infectious pathogens from contaminated fomites, for biocontainment, and for safety. We designed several experiments to determine the effects of commonly encountered processes on steam penetration and substrate heat exposure. We used biologic indicators as a proxy for steam penetration. We used the time bedding spent above 121 °C as a proxy for substrate cumulative heat exposure. This temperature was measured using a high-temperature data logger. We first examined the effect of stacking cages with various bedding types on steam penetration. We then autoclaved soiled bedding and studied the variables of bedding type, bagging style, presence of diet and water in the cage, and amount of time between cage change out on steam penetration and cumulative heat exposure. For clean bedding, we found adequate steam penetration regardless of bedding type, cycle program, or location of the cage in the bulk autoclave. For the soiled bedding experiments, there were no differences between bedding types noted. Placement of cages inside plastic bagging increased the amount of time the bedding spent above 121 °C on average but not significantly. There was no difference in steam penetration of bedding or time spent above 121 °C for 2- or 4-wk cage change-out schedules. When cages were autoclaved with diet and water, the time the bedding spent above 121 °C was significantly less than when autoclaving bedding alone, but there was adequate steam penetration for all cages. This study demonstrates that common practices in the industry are effective. Based on the results of this study, it is recommended that each institution evaluate their autoclaving practices and confirm that those practices are sufficient and effective.
为使啮齿动物群体免受有害传染源的影响，实验动物护理计划经常采用经过消毒的笼具和用品。消毒后的笼具对于防止传染性病原体通过受污染的污染物传播、进行生物防护以及保障安全都很重要。我们设计了几个实验来确定常见处理过程对蒸汽渗透和垫料热暴露的影响。我们使用生物指示剂作为蒸汽渗透的替代指标。我们将垫料在121°C以上的停留时间作为垫料累积热暴露的替代指标。该温度使用高温数据记录器进行测量。我们首先研究了堆叠装有不同类型垫料的笼子对蒸汽渗透的影响。然后我们对脏垫料进行高压灭菌，并研究垫料类型、装袋方式、笼内是否有食物和水以及更换笼子之间的时间间隔等变量对蒸汽渗透和累积热暴露的影响。对于干净垫料，无论垫料类型、循环程序或笼子在大容量高压灭菌器中的位置如何，我们都发现有足够的蒸汽渗透。对于脏垫料实验，未发现不同垫料类型之间存在差异。将笼子放在塑料袋内平均会增加垫料在121°C以上的停留时间，但不显著。对于2周或4周的换笼时间表，垫料的蒸汽渗透或在121°C以上的停留时间没有差异。当笼子与食物和水一起进行高压灭菌时，垫料在121°C以上的停留时间明显少于单独对垫料进行高压灭菌时，但所有笼子都有足够的蒸汽渗透。本研究表明该行业的常见做法是有效的。基于本研究的结果，建议每个机构评估其高压灭菌做法，并确认这些做法是充分且有效的。
