Switch to oral antibiotics in the treatment of infective endocarditis is not associated with increased risk of mortality in non-severely ill patients.

Although many international guidelines exist for the management of infective endocarditis (IE), recommendations are lacking on the opportunity of switching antibiotics from the intravenous (IV) to oral route during treatment. We present a cohort study of 426 cases of IE over a period of 13 years (2000-2012), including 369 cases of definite IE according to the Duke criteria. Predictors of mortality were identified using the Cox proportional hazard analysis. The median (range) age at diagnosis was 64.5 (7-98) years. One hundred six patients (25%) had healthcare-associated IE. Oral streptococci (n = 99, 23%) and Staphylococcus aureus (n = 81, 19%) were the predominant microorganisms. Ninety-two patients (22%) died during follow-up. After an initial phase of IV antibiotherapy, 214 patients (50%) were switched to oral route a median (range) of 21 (0-70) days after diagnosis of IE. Patients in the oral group had fewer comorbidities, and criteria of severity at inclusion and were less frequently infected by S. aureus. Oral antibiotics were amoxicillin alone in 109 cases or a combination therapy of clindamycin, fluoroquinolone, rifampicin and/or amoxicillin in 46 cases, according to the susceptibility of the microorganisms. In the multivariate analysis, a switch to oral route was not associated with an increased risk of mortality. During follow-up, only two relapses and four reinfections were observed in the oral group (compared to nine and eight in the IV group, respectively). In this study, switching to oral administration was not associated with an increased risk of relapse or reinfection. These promising results need to be confirmed by prospective studies.