ERP Micro December 2019

Bruker clarification to the end-customer

July 2019

The conclusion of the investigation was sent to the end-customer by email.

In conclusion, the isolate is an atypical L. innocua strain regarding the rMLST with only 80% of the ribosomal genes assigned to L. innocua . This has certainly impact on the measured mass spectrum generated by with the MBT. The most abundant proteins within a range of 2,000 to 20,000 Daltons are measured by the MBT; most of these proteins are ribosomal proteins. The subtyping module for Listeria speciation is designed to get identification to L. monocytogenes if some atypical spectra contain specific peaks that are usually characteristic to L. monocytogenes species, in order to avoid any risk regarding public health. This is certainly the case for this peculiar isolate. Bruker is continuously looking for atypical strains to improve the identification results. The studied isolate is one of these. • Library updates The validation studies started in 2016 with the MBT Library 6903, which is the minimum version to be used for the MBT configuration. The Table 3 describes the yearly updates of the library since the two OMA approvals, with - the release dates, - the MBT Library names, - the content regarding the number of o Main Spectra (MSP) generated from strains from various origins, o genus o and species. Table 3: Update of the MBT Library Month/Year MBT Library Number of Main Spectra (MSP) Number of genus Number of species April 2016 MBT Library 6903 Library used during the validation study 6903 424 2461 April 2017 MBT Library 7311 7311 434 2509 April 2018 MBT Library 7854 7854 471 2747 April 2019 MBT Library 8468 8468 540 2969

This is of course done according to defined procedures and quality controls. Access to the strains used to generate the MSPs is always possible in case of need.

The users are informed by getting a Release Note proving the added new species, the deleted MSP entries and the reason, the renaming related to taxonomy changes, and the changes to matching-hints, i.e. the species that cannot be differentiated of the group of species (Please see the additional document entitled “7311_MSP_Library_Release Note”). Additionally, the users receive the full list of species in the new MBT Library. It is as well