Spicher G, Peters J, Borchers U
Robert Koch Institut, Berlin.
Zentralbl Hyg Umweltmed. 1999 Feb;201(6):541-53.
For the spores of Bacillus subtilis and Bacillus stearothermophilus as well as for spore earth (acc. DIN 58,946 Part 4 of August 1982), the dependence of resistance on the superheating of the steam used to kill germs was determined. A material (glass fibre fleece) was used as the germ carrier which does not superheat on contact with steam. The temperature of the saturated steam was 100 degrees C (B. subtilis) and 120 degrees C (B. stearothermophilus and spore earth). The yardstick for the resistance of the spores or bioindicators was the exposure period of the saturated or superheated steam at which 50% of the treated test objects no longer showed any viable test germs. The spores of Bacillus subtilis were far more sensitive to superheating of steam and reacted far more than the spores of Bacillus stearothermophilus and the germs in the spore earth. When superheating by 4 Kelvin the spores of Bacillus subtilis were approximately 2.5 times more resistant than they were to saturated steam. The resistance of Bacillus stearothermophilus and spore earth was only slightly higher up to superheating by 10 Kelvin. The spores of Bacillus subtilis had the highest resistance during superheating by 29 Kelvin; they were 119 times more resistant than they were to saturated steam. The resistance maximum of the spores of Bacillus stearothermophilus was at an superheating by around 22 Kelvin. However, the spores were only 4.1 times more resistant than they were to saturated steam. When using steam to kill germs, we must expect superheated steam. This raises the question whether the spores of Bacillus stearothermophilus, with their weaker reaction to the superheating of steam, are suitable as test germs for sterilisation with steam in all cases.
针对枯草芽孢杆菌和嗜热脂肪芽孢杆菌的孢子以及芽孢土壤（依据1982年8月的德国工业标准DIN 58946第4部分），测定了其抗性对用于杀菌的蒸汽过热的依赖性。使用一种（玻璃纤维绒）作为与蒸汽接触时不会过热的载菌材料。饱和蒸汽的温度为100℃（枯草芽孢杆菌）和120℃（嗜热脂肪芽孢杆菌和芽孢土壤）。孢子或生物指示剂抗性的衡量标准是饱和或过热蒸汽的暴露时间，在此暴露时间下，50%的处理过的测试对象不再显示任何存活的测试菌。枯草芽孢杆菌的孢子对蒸汽过热更为敏感，其反应远大于嗜热脂肪芽孢杆菌的孢子和芽孢土壤中的菌。当过热4开尔文时，枯草芽孢杆菌的孢子抗性约为其对饱和蒸汽抗性的2.5倍。在过热至10开尔文之前，嗜热脂肪芽孢杆菌和芽孢土壤的抗性仅略有提高。枯草芽孢杆菌的孢子在过热29开尔文时抗性最高；其抗性是对饱和蒸汽抗性的119倍。嗜热脂肪芽孢杆菌孢子的抗性最大值出现在过热约22开尔文时。然而，此时孢子的抗性仅为其对饱和蒸汽抗性的4.1倍。在使用蒸汽杀菌时，我们必须考虑到过热蒸汽的存在。这就引发了一个问题，即嗜热脂肪芽孢杆菌的孢子对蒸汽过热反应较弱，在所有情况下是否都适合作为蒸汽灭菌的测试菌。
