Increasing numbers and complexity of Staphylococcus aureus bloodstream infection - 14 years of prospective evaluation at a German tertiary care center with multi-center validation of findings
Mathé P, Göpel S, Hornuss D, Tobys D, Käding N, Eisenbeis S, Kohlmorgen B, Trauth J, Gölz H, Walker SV, Mischnik A, Peter S, Hölzl F, Rohde AM, Behnke M, Fritzenwanker M, Häcker G, Steffens B, Vehreschild M, Kramme E, Falgenhauer J, Peyerl-Hoffmann G, Seifert H, Rupp J, Gastmeier P, Imirzalioglu C, Tacconelli E, Kern W, Rieg S; DZIF R-Net Study Group
Objectives: Staphylococcus aureus bloodstream infection (SAB) is a common and severe infection. This study aims to describe temporal trends in numbers, epidemiological characteristics, clinical manifestations, and outcomes of SAB.
Methods: We performed a post-hoc analysis of three prospective SAB cohorts at the University Medical Center Freiburg between 2006 and 2019. We validated our findings in a large German multi-center cohort of five tertiary care centers (R-Net consortium, 2017-2019). Time-dependent trends were estimated using Poisson or beta regression models.
Results: We included 1,797 patients in the mono-centric and 2,336 patients in the multi-centric analysis. Overall, we observed an increasing number of SAB cases over 14 years (+6.4%/year and 1,000 patient days, 95%-CI: +5.1%-7.7%), paralleled by an increase in the proportion of community-acquired SAB (+4.9%/year (95%-CI: +2.1-7.8%), CA-SAB) and a decrease in the rate of methicillin-resistant-SAB (-8.5%/year (95%-CI: -11.2-(-5.6%)), MRSA-SAB). All of these findings were confirmed in the multi-center validation cohort (+6.2% cases per 1000 patient cases/year (95%-CI: -0.6-+12.6%), CA-SAB +8.7% (95%-CI: -1.2-+19.6%), MRSA-SAB -18.6% (95%-CI: -30.6-(-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: +3.6-13.5%, p<0.001), alongside an overall higher level of comorbidities (Charlson comorbidity score +0.23 points/year, 95%-CI: +0.09-0.37, p=0.005). At the same time, the rate of deep-seated foci like osteomyelitis or deep-seated abscesses significantly increased (+6.7%, 95%-CI: +3.9-9.6%, p<0.001). A reduction of in-hospital mortality by 0.6% per year (95%-CI: 0.08-1%) was observed in the subgroup of patients with infectious diseases (ID) consultations.
Conclusions: We found an increasing number of SAB combined with a significant increase in comorbidities and complicating factors in tertiary care centers. The resulting challenges in securing adequate SAB management in the face of high patient turnover will become an important task for physicians.