A two-step approach for the investigation of a Clostridium difficile outbreak by molecular methods

Abstract

Abstract The recent review “How to: molecular investigation of a hospital outbreak” written by Nutman and Marchaim published in Clinical Microbiology and Infection journal summarized data on typing methods used for a hospital outbreak investigation. Regarding Clostridium difficile infection (CDI), a whole genome sequencing (WGS) was recommended as the initial and a single molecular test for characterisation of C. difficile isolates in a suspected outbreak situation. According to results from our survey on typing capacity for C. difficile in Europe, whole genome sequencing was available only in five National reference laboratories for C. difficile in 2017 in Europe. Because of limited availability of WGS, we suggest a two-step approach that includes the typing of C. difficile isolates with a high discriminatory method, capillary electrophoresis ribotyping and the subtyping of C. difficile isolates by Multilocus Variable-number Tandem-repeats Analysis (MLVA) and/or WGS when a common cluster of CDIs is confirmed. This two-step approach would provide an epidemiological relevant timeframe for confirmation of a suspected CDI outbreak as well as being cost-effective by selecting highly related C. difficile isolates for further investigation.