Association of persistent positive blood cultures and infective endocarditis: a cohort study among patients with suspected infective endocarditis

Objectives To ascertain whether infective endocarditis (IE) was associated with persistent bacteraemia/candidaemia among patients with suspected IE. Methods This study included bacteraemic/candidaemic adult patients with echocardiography and follow-up blood cultures. Persistent bacteraemia/candidaemia was defined as continued positive blood cultures with the same microorganism for 48h or more after antibiotic treatment initiation. Each case was classified for IE by the Endocarditis Team. Results Among 1962 episodes of suspected IE, IE (605; 31%) was the most prevalent infection type. Persistent bacteraemia/candidaemia was observed in 426 (22%) episodes. Persistent bacteraemia was more common among episodes with Staphylococcus aureus bacteraemia compared to episodes with positive blood cultures for other pathogens (32%, 298/933 versus 12%, 128/1029; P<0.001). Multivariable analysis demonstrated that cardiac predisposing factors (aOR 1.84, 95% CI 1.31-2.60), community or non-nosocomial healthcare-associated (2.85, 2.10-3.88), bacteraemia by high-risk bacteria, such as S. aureus, streptococci, enterococci or HACEK (1.84, 1.31-2.60), two or more positive sets of index blood cultures (6.99, 4.60-10.63), persistent bacteraemia/candidaemia for 48 hours from antimicrobial treatment initiation (1.43, 1.05-1.93), embolic events within 48h from antimicrobial treatment initiation (12.81, 9.43-17.41), and immunological phenomena (3.87, 1.09-1.78) were associated with infective endocarditis. Conclusions IE was associated with persistent bacteraemia/candidaemia, along with other commonly associated factors.