Staphylococcus aureus from prosthetic joint infections and blood cultures display the same genetic background
Abstract. Introduction: According to a growing proportion of older people the number of patients living with a hip or knee arthroplasty will be more prevalent and at risk of contracting a hematogenous prosthetic joint infections (PJI) during their lifetime.  Hematogenous PJIs are primarily associated with Staphylococcus aureus and the risk of contracting a hematogenous PJI following a S. aureus bacteremia is 30 – 40 %. The aim was to explore if identical strains of S. aureus were present in each patient and, if so, the genomic differences between the paired isolates of S. aureus obtained from blood cultures and from tissue biopsies. Material and Methods: All patients from 2005 to 2020 with a PJI and the presence of a temporal concomitant bacteremia due to S. aureus were included in the study. Paired isolates of S. aureus from tissue biopsies and blood cultures were whole genome sequenced. Results: Twenty-four episodes of PJI in 23 patients were identified. All pairwise analysed isolates from individual patients belonged to the same multi-locus sequence type (ST), clonal complex (CC), and core genome multilocus sequence typing (cgMLST) complex type. The median number of single nucleotide polymorphisms (SNPs) in the conserved core genomes between the pairwise isolates was 3 SNPs, with a maximum number of 16. Conclusion: The identical cgMLST complex types and low levels of SNP differences between the paired isolates of S. aureus from blood cultures and tissue biopsies suggest hematogenous seeding in all cases of PJI in the current patient cohort.