Increasing numbers and complexity of Staphylococcus aureus bloodstream infectiond14 years of prospective evaluation at a German tertiary care centre with multi-centre validation of findings

Objectives: Staphylococcus aureus bloodstream infection (SAB) is a common and severe infection. This study aims to describe temporal trends in numbers, epidemiological characteristics, clinical manifesta-tions, and outcomes of SAB. Methods: We performed a post-hoc analysis of three prospective SAB cohorts at the University Medical Centre Freiburg between 2006 and 2019. We validated our findings in a large German multi-centre cohort of five tertiary care centres (R-Net consortium, 2017-2019). Time-dependent trends were esti-mated using Poisson or beta regression models. Results: We included 1797 patients in the mono-centric and 2336 patients in the multi-centric analysis. Overall, we observed an increasing number of SAB cases over 14 years (6.4%/year and 1000 patient days, 95% CI: 5.1% to 7.7%), paralleled by an increase in the proportion of community-acquired SAB (4.9%/year [95% CI: 2.1% to 7.8%]) anda decrease in the rate of methicillin-resistant-SAB (-8.5%/year [95% CI:-11.2% to-5.6%]). All of these findings were confirmed in the multi-centre validation cohort (6.2% cases per 1000 patient cases/year [95% CI:-0.6% to 12.6%], community-acquired-SAB 8.7% [95% CI:-1.2% to 19.6%], methicillin-resistant S. aureus-SAB-18.6% [95% CI:-30.6 to-5.8%]). Moreover, we found an increasing proportion of patients with multiple risk factors for complicated/difficult-to-treat SAB (8.5%/year, 95% CI: 3.6% to 13.5%, p < 0.001), alongside an overall higher level of comorbidities (Charlson comorbidity score 0.23 points/year, 95% CI: 0.09 to 0.37, p 0.005). At the same time, the rate of deep-seated foci such as osteomyelitis or deep-seated abscesses significantly increased (6.7%, 95% CI: 3.9% to 9.6%, p < 0.001). A reduction of in-hospital mortality by 0.6% per year (95% CI: 0.08% to 1%) was observed in the subgroup of patients with infectious diseases consultations. Discussion: We found an increasing number of SAB combined with a significant increase in comorbidities and complicating factors in tertiary care centres. The resulting challenges in securing adequate SAB management in the face of high patient turnover will become an important task for physicians. Philipp Math?e, Clin Microbiol Infect 2023;29:1197.e9-1197.e15 (c) 2023 Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases.

Automated summary

This study aims to describe the temporal trends, epidemiological characteristics, clinical manifestations, and outcomes of Staphylococcus aureus bloodstream infection (SAB). The findings showed an increasing number of SAB cases, an increase in community-acquired SAB, and a decrease in methicillin-resistant SAB. There was also an increase in risk factors for complicated/difficult-to-treat SAB and a higher level of comorbidities. The rate of deep-seated foci such as osteomyelitis or deep-seated abscesses significantly increased. In-hospital mortality decreased in patients with infectious diseases consultations.