Notification of bacterial strains made available by the UK National Collection of Type Cultures in 2023.

Many microbial culture collections, like the UK's National Collection of Type Cultures, add biological material such as bacterial strains to their holdings over time in a process known as accessioning. Here, we report on the 101 bacterial strains made available to scientists in the UK and globally by the National Collection of Type Cultures in 2023. Strains that are received are preserved, identified to species level and confirmed to be viable and pure. Genomic and metadata (where these are available) are made accessible via the UKHSA Culture Collections online catalogue. Commentary on the strains' provenance and significance is presented, and wider trends in accessioning between 2017 and 2023 are examined. On average, ~101 strains were made available to the scientific community each year between 2017 and 2023. Fewer strains of veterinary provenance were made available than any other kind of strain, highlighting a need to accession more of these strains. However, there has been growth in the proportion of strains that are either antimicrobial resistant or type strains of novel microbial taxa, demonstrating that the NCTC program of accessioning helps support its function as a contemporary public health resource and repository for prokaryotic taxonomists.