BackgroundPeriprosthetic joint infections (PJIs) can lead to higher re-revision rates and even higher mortality rates that may be associated with the responsible microorganism. We evaluated microorganisms that cause early PJIs in primary total hip and knee arthroplasty (THA and TKA), and examined mortality as well as PJI re-revision rates after these PJIs, using a combined dataset from the Dutch Arthroplasty Register (LROI) and the Dutch National Nosocomial Surveillance Network (PREZIES). Secondly, the most common microorganisms that cause PJIs were described according to patient and implant survival. MethodsWe included all PREZIES-confirmed PJIs (n = 1,648) from the combined dataset in which primary THAs and TKAs (2012 to 2018) from the LROI and PREZIES were case-level matched. Kaplan-Meier survival analyses were performed to determine mortality and PJI re-revision rates following PJI revision. ResultsThe most prevalent microorganism in THAs and TKAs was Staphylococcus aureus (THA 34%; TKA 39%), followed by Coagulase-negative staphylococci (CoNS) (THA 20%; TKA 19%), with Staphylococcus epidermidis (THA 12%; TKA 11%) as the most common subtype, and Enterococcus species (THA 8.6%; TKA 5.9%). The 5-year mortality was 15% (95% confidence interval [CI]: 13 to 18) and 18% (CI: 14 to 21) for THA and TKA patients, respectively. The 5-year PJI re-revision rate was 28% (CI: 24 to 34) for THAs and 30% (CI: 24 to 38) for TKAs. In deceased THA patients who had a PJI, Enterococcus species (14%) were more often registered as microorganisms responsible for the PJI than S. epidermidis (8.5%). ConclusionOver half of the early PJIs in THAs and TKAs in the Netherlands were caused by Staphylococcus aureus and CoNS including Staphylococcus epidermidis. Both 5-year mortality and PJI re-revision rates following PJI were relatively high.