Non–β-hemolytic Streptococcal Bacteremia in Patients With Heart Valve Prosthesis—Is It Always Infective Endocarditis?

TL;DR

Patients with heart valve prostheses and non–β-hemolytic streptococcal bacteremia are at high risk for infective endocarditis but often receive inadequate treatment, leading to relapses.

Contribution

This study identifies a high risk of infective endocarditis in patients with heart valve prostheses and non–β-hemolytic streptococcal bacteremia, highlighting inadequate treatment and relapse risks.

Findings

40% of NBHSB episodes in patients with HVP were classified as definite infective endocarditis.

Most patients with possible IE did not receive long-course antibiotic treatment.

Short antibiotic courses (<14 days) were associated with NBHSB relapses in some patients.

Abstract

Non–β-hemolytic streptococci are among the most common causative agents of infective endocarditis (IE). Patients with a heart valve prosthesis (HVP) have a high risk of IE. We aimed to determine the risk for IE in patients with HVP and non–β-hemolytic streptococcal bacteremia (NBHSB) and to study NBHSB relapse depending on treatment duration.

Adults with HVP and NBHSB from 2015 to 2018 in the region of Skåne, Sweden, were identified through the Clinical Microbiology Laboratory in Lund and evaluated in a population-based investigation. Data were collected from medical records according to a predefined protocol.

A total of 110 NBHSB episodes in 89 patients with HVP were included. In 40 episodes (36%), the patients had definite IE, in 69 possible IE, and 1 had rejected IE according to the European Society of Cardiology 2015 criteria. Of the 70 patients without a definite diagnosis of IE, 28 (40%) were treated with antibiotics as if they had IE. There were 7 NBHSB relapses, and 6 of these occurred in patients with possible IE. Four relapses occurred in patients who received antibiotics for <14 days. Three patients with possible IE were diagnosed with definite IE at the time of the relapse.

Patients with NBHSB and HVP have a high risk for IE and should be thoroughly investigated. Most patients with NBHSB and HVP who fulfilled criteria for possible IE did not receive long-course antibiotic treatment. Moreover, some patients treated with a short course of antibiotics experienced NBHSB relapse.

Many patients with non–β-hemolytic streptococcal bacteremia and heart valve prosthesis had possible infective endocarditis, but most were not treated as such. Some had a relapse, suggesting inadequate treatment. These patients are at high risk of infective endocarditis, warranting thorough investigation.

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