Temporal evolution of prognosis in patients with infective endocarditis and persistently positive blood cultures over the last 25 years: the importance of early surgery

Background/Purpose

The persistence of positive blood cultures at 72 hours after the initiation of appropriate antibiotic therapy is a prognostic factor in patients with infective endocarditis (IE). Our objective was to evaluate temporal trends in the outcomes and management of patients with persistently positive blood cultures (PPBC) over the last 25 years.

Methods

Prospective cohort of patients with IE treated at three Spanish tertiary hospitals between 1997 and 2023. The prevalence of episodes with PPBC was analysed, as well as the prognostic differences with patients who achieved negative blood cultures at 72 hours, and the temporal trends in the clinical, microbiological, and prognostic profiles of this group of patients.

Results

Of a total of 1,751 episodes of left-sided IE, 1,286 (73.4%) had positive blood cultures at admission and 328 episodes had PPBC, constituting our study group.

The proportion of patients with PPBC did not change significantly over time, representing 18.7% of all patients.

Patients with PPBC had higher in-hospital mortality than those who achieved negative blood cultures at 48-72 hours after the initiation of targeted antibiotic therapy (39% vs 25%; p<0.001).

Regarding the microbiological profile in patients with PPBC, the most frequently implicated microorganisms were S. aureus (30.2%), coagulase-negative staphylococci (19.6%), and enterococci (18.6%), with a statistically significant temporal trend towards an increase in enterococcal infections over the last 10 years (12% vs 22%; p=0.026) (Table).

A total of 57% (190/328) of patients with PPBC underwent surgery during admission, with no significant changes in the percentage of patients who received surgery over time.

However, we found a statistically significant temporal trend towards a progressive decrease in in-hospital mortality in the PPBC group (51% in 1997-2007 vs 31% in 2013-2023; p<0.001), and a progressive decrease in the incidence of septic shock and acute kidney injury at the expense of a gradual reduction in the time elapsed between diagnosis and surgery (11 days vs 6 days; p<0.001) (Figure).

Conclusions

Patients with PPBC represent approximately 1 in 5 patients with left-sided IE and have a mortality rate twice that of those who achieve negative blood cultures. In our cohort, we observed a progressive decrease over time in in-hospital complications and mortality in this group of patients, linked to a gradual reduction in time to surgery. Therefore, we consider early surgery to be crucial for improving prognosis in this entity.