Sagripanti J L, Bonifacino A
Molecular Biology Branch, Food and Drug Administration, Rockville, MD 20857, USA.
Am J Infect Control. 1996 Oct;24(5):364-71. doi: 10.1016/s0196-6553(96)90024-3.
The relatively limited variety of surfaces and geometries challenged in current sporicidal testing reduces the predictive value of these analyses when extrapolated to the wide variety of medical devices. The unknown spore load being challenged and the qualitative nature (growth/no growth) of those tests further prevent precise comparison among liquid chemical disinfectants. Hence, the relative activity of different chemical substances has not been clearly established, hindering selection of the best agent for each clinical situation.
A micromethod was developed to assess sporicidal activity against Bacillus subtilis spores deposited on three different medical devices; carbon steel dental burs, silicone-rubber medical catheters, and titanium-alloy dental abutment screws. The spore load on each device and the recovery after three analytical steps were quantitatively assessed with spores radiolabeled with carbon 14 methionine.
The killing of 2 to 7 x 10(6) spores loaded on three different devices and exposed to glutaraldehyde, formaldehyde, copper ascorbate, hydrogen peroxide, peracetic acid, sodium hypochlorite, or phenol for 30 minutes at 20 degrees C ranged from a 10(3)-fold decrease for 10% hydrogen peroxide to zero decrease for 5% phenol. Our results suggest that the nature of the surface being challenged may affect the sporicidal activity of some chemical agents.
The quantitative data presented allow comparison of the sporicidal effect of different liquid chemical agents. These findings may help prevent an overestimation of sporicidal activity and possible transmission of pathogens from the surface of improperly decontaminated medical devices.
当前杀孢子剂测试所涉及的表面和几何形状种类相对有限，这使得这些分析结果外推至各种各样的医疗设备时，其预测价值降低。所测试的未知孢子负载量以及这些测试的定性性质（生长/不生长）进一步阻碍了液体化学消毒剂之间的精确比较。因此，不同化学物质的相对活性尚未明确确立，这不利于针对每种临床情况选择最佳药剂。
开发了一种微量方法，以评估针对沉积在三种不同医疗设备上的枯草芽孢杆菌孢子的杀孢子活性；碳钢牙科车针、硅橡胶医用导管和钛合金牙种植体基台螺丝。使用用碳14甲硫氨酸放射性标记的孢子，对每个设备上的孢子负载量以及三个分析步骤后的回收率进行定量评估。
在20℃下，将负载在三种不同设备上的2至7×10⁶个孢子暴露于戊二醛、甲醛、抗坏血酸铜、过氧化氢、过氧乙酸、次氯酸钠或苯酚中30分钟，杀灭率从10%过氧化氢的10³倍降低到5%苯酚的零降低。我们的结果表明，所测试的表面性质可能会影响某些化学药剂的杀孢子活性。
所呈现的定量数据允许比较不同液体化学药剂的杀孢子效果。这些发现可能有助于防止高估杀孢子活性以及病原体从未正确消毒的医疗设备表面的可能传播。
