BACKGROUND Sporicidal surface disinfection is recommended to control transmission of Clostridium difficile in healthcare facilities. EN 17126 provides a method to determine the sporicidal activity in suspension and has been approved as a European standard. In addition, a sporicidal surface test has been proposed. AIM To determine the interlaboratory reproducibility of a test method for evaluating the susceptibility of a C. difficile spore preparation to a biocidal formulation following the 4-field test (EN 16615 methodology). METHODS Nine laboratories participated. C. difficile NCTC 13366 spores were used. Glutaraldehyde (1% and 6%; 15 min) and peracetic acid (PAA; 0.01% and 0.04%; 15 min) were used to determine the spores' susceptibility in suspension in triplicate. FINDINGS One-percent glutaraldehyde revealed a mean decimal log10 reduction of 1.03 with variable results in the nine laboratories (0.37-1.49) and a reproducibility of 0.38. The effect of 6% glutaraldehyde was stronger (mean: 2.05; range: 0.96-4.29; reproducibility: 0.86). PAA revealed similar results. An exemplary biocidal formulation based on 5% PAA was used at 0.5% (non-effective concentration) and 4% (effective concentration) to determine the sporicidal efficacy (4-field test) under clean conditions in triplicate with a contact time of 15 min. When used at 0.5% it demonstrated an overall log10 reduction of 2.68 (range: 2.35-3.57) and at 4% of 4.61 (range: 3.82-5.71). The residual contamination on the three primarily uncontaminated test fields was <50 cfu/25 cm2 in one out of nine laboratories (0.5%) and in seven out of nine laboratories (4%). CONCLUSION The interlaboratory reproducibility seems to be robust.

中文翻译：

---

按照4场测试方法评估艰难梭菌孢子敏感性的测试方法的实验室间可重复性。

背景技术推荐使用杀孢子表面消毒来控制艰难梭菌在医疗机构中的传播。EN 17126提供了一种测定悬浮液中杀孢子活性的方法，并已被批准为欧洲标准。另外，已经提出了杀孢子表面测试。目的确定4场试验（EN 16615方法）后评估艰难梭菌孢子制剂对杀生物制剂敏感性的试验方法的实验室间再现性。方法有9个实验室参加。使用艰难梭菌NCTC 13366孢子。戊二醛（分别为1％和6％； 15分钟）和过乙酸（PAA； 0.01％和0.04％； 15分钟）用于测定孢子在悬浮液中一式三份的敏感性。结果发现9％的戊二醛在10个实验室中的平均十进制log10降低了1.03，结果可变（0.37-1.49），重现性为0.38。6％戊二醛的效果更强（平均值：2.05；范围：0.96-4.29；再现性：0.86）。PAA显示了相似的结果。以0.5％（无效浓度）和4％（有效浓度）为基础，使用基于5％PAA的示例性杀生物制剂，在干净的条件下以15分钟的接触时间一式三份测定杀孢子效力（4现场测试）。 。当以0.5％的比例使用时，它的总体log10降低为2.68（范围：2.35-3.57），而以4.61的4％（范围：3.82-5.71）降低。在9个实验室中，有1个实验室的三个基本未污染的测试场上的残留污染小于50 cfu / 25 cm2。5％）和9个实验室中的7个（4％）。结论实验室间的再现性似乎很强。