Prevalence of Infective Endocarditis in Streptococcal Bloodstream Infections Is Dependent on Streptococcal Species

Abstract

Background: Streptococci frequently cause infective endocarditis (IE), yet the prevalence of IE in patients with bloodstream infections (BSIs) caused by different streptococcal species is unknown. We aimed to investigate the prevalence of IE at species level in patients with streptococcal BSIs. Methods: We investigated all patients with streptococcal BSIs, from 2008 to 2017, in the Capital Region of Denmark. Data were crosslinked with Danish nationwide registries for identification of concomitant hospitalization with IE. In a multivariable logistic regression analysis, we investigated the risk of IE according to streptococcal species adjusted for age, sex, ≥3 positive blood culture bottles, native valve disease, prosthetic valve, previous IE and cardiac device. Results: Among 6,506 cases with streptococcal BSIs (mean age 68.1 years (SD 16.2), 52.8% men) the IE prevalence was 7.1% (95% CI: 6.5-7.8%). The lowest IE prevalence was found with S. pneumoniae 1.2% (0.8-1.6%) and S. pyogenes 1.9% (0.9-3.3%). An intermediary IE prevalence was found with S. anginosus 4.8% (3.0-7.3%), S. salivarius 5.8% (2.9-10.1%) and S. agalactiae 9.1% (6.6-12.1%). The highest IE prevalence was found with S. mitis/oralis 19.4% (15.6-23.5%), S. gallolyticus (formerly S. bovis) 30.2% (24.3-36.7%), S. sanguinis 34.6% (26.6-43.3%), S. gordonii 44.2% (34.0-54.8%) and S. mutans 47.9% (33.3-62.8%). In multivariable analysis using S. pneumoniae as reference, all species except S. pyogenes were associated with significantly higher IE risk, with the highest risk found with S. gallolyticus OR 31.0 (18.8-51.1), S. mitis/oralis OR 31.6 (19.8-50.5), S. sanguinis OR 59.1 (32.6-107), S. gordonii OR 80.8 (43.9-149) and S. mutans OR 81.3 (37.6-176). Conclusions: The prevalence of IE in streptococcal BSI is species dependent with S. mutans, S. gordonii, S. sanguinis, S. gallolyticus and S. mitis/oralis having the highest IE prevalence and the highest associated IE risk after adjusting for IE risk factors.