Risk factors for community-acquired metastatic infections without infective endocarditis in patients with...

Staphylococcus aureus bacteremia (SAB) can cause serious complications, such as infective endocarditis (IE); however, the risk factors for developing metastatic infection without infective endocarditis (MI without IE) remain unclear. This study aimed to identify risk factors associated with MI without IE in patients with SAB.

A retrospective cohort study was conducted on 102 patients diagnosed with SAB at Tottori University Hospital between January 1, 2014, and December 31, 2021. The primary endpoint was diagnosis of MI without IE within 84 days of SAB onset. A modified Poisson regression analysis was used to analyze risk factors. Secondary endpoints were the type and number of metastatic infections and mortality at 7, 28, and 84 days.

Patients with MI without IE tended to have bacteremia of unknown source and a longer time to initiation of appropriate antimicrobial therapy than Non-metastatic SAB patients. Modified Poisson regression analysis showed that delayed antimicrobial initiation (risk ratio 7.16, 95% confidence interval 2.77-18.5, P < 0.05) and bacteremia of unknown source (risk ratio 2.50, 95% confidence interval 1.49-4.20, P < 0.05) were significantly associated with MI without IE. A non-linear association was also observed, with increasing risk up to day 10 before plateauing.

In patients with SAB, delayed initiation of appropriate antimicrobials and bacteremia of unknown origin are key risk factors associated with the development of MI without IE. Recognizing these factors may enable earlier detection and timely intervention, potentially improving patient prognosis.