title: DNA-Seq of Cutibacterium acnes: blood culture
design: Two medical microbiology laboratories localized at German university medical centres and one major privately-owned laboratory serving several hospitals with orthopaedics departments participated in the study. Criteria for defining infection-associated isolates were as specified in table 1. Additionally, isolates from single positive blood cultures without repeated isolation of C. acnes from the same patient and no clinical signs of localised infection were included as control group (commensal isolates). Participating microbiologists at each laboratory independently reviewed if inclusion criteria were met and submitted isolates to the University Medical Centre Hamburg-Eppendorf for further analysis. The corresponding diagnosis was submitted with the isolates, as well as source of isolation, but no patient data were submitted. Upon arrival, isolates were cultured on Schaedler agar (Oxoid, Basingstoke, UK) for three to five days at 37C under anaerobic conditions. Species identification was achieved using a Biotyper MALDI-Tof instrument (Bruker, Bremen, Germany). Isolates were stored at -80C until further use.