Demographic characteristics, predisposing factors, clinical presentations, echocardiographic findings, complications, and outcomes of patients with viridans streptococcal endocarditis

Background: Several microorganisms are associated with infective endocarditis (IE), but the most common IE causes are staphylococci and streptococci. Among streptococci, the viridans group streptococci are responsible for a considerable percentage of all IE cases. Methods: Since 2006, the Iranian Registry of Infective Endocarditis has recorded information regarding all adult patients with a definite or possible IE diagnosis according to the modified Duke criteria. Patients with viridans streptococcal endocarditis were detected through three blood culture sets. The patients' demographic characteristics, predisposing factors, clinical presentations, and echocardiographic findings were recorded. Results: Of 731 patients diagnosed with endocarditis, viridans streptococci were found in 46 (6.3%) patients, consisting of 28 (60.9%) men and 18 (39.1%) women at a mean age of 42.56 ± 15.46 years, who were subsequently included in the study. Among the 46 patients with viridans streptococcal endocarditis, 26 had a subacute course, whereas 20 had an acute course. Vegetation was detected in 35 patients. All the patients were treated with the standard antibiotic regimen for viridans streptococcal endocarditis, and cardiac surgery was performed on 16 patients. Conclusions: Clinicians should pay sufficient heed to the following points in all cases of viridans streptococcal endocarditis: firstly, an appropriate antibiotic regimen must be based on a precise minimal inhibitory concentration determination for the usual antibiotics. Secondly, since prolonged antibiotic therapy is crucial to the eradication of microorganisms within vegetation, all patients with viridans streptococcal endocarditis must receive an adequate therapy course.