Interlaboratory reproducibility of a test method following four-field test methodology to evaluate the susceptibility of Clostridium difficile spores

Publication date: Available online 12 June 2019Source: Journal of Hospital InfectionAuthor(s): Stefanie Gemein, Jürgen Gebel, Bärbel Christiansen, Heike Martiny, Lutz Vossebein, Florian H.H. Brill, Maja Decius, Maren Eggers, Torsten Koburger-Janssen, Maren Meckel, Sebastian Werner, Birgit Hunsinger, Thomas Selhorst, Günter Kampf, Martin ExnerSummarySporicidal 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 of the study was 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 four-field test (EN 16615 methodology). 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. 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....
Source: Journal of Hospital Infection - Category: Infectious Diseases Source Type: research