Guidelines for the diagnosis and antibiotic treatment of endocarditis in adults: a report of the Working Party of the British Society for Antimicrobial Chemotherapy

Abstract

The BSAC guidelines on treatment of infectious endocarditis (IE) were last published in 2004. The guidelines presented here have been updated and extended to reflect developments in diagnostics, new trial data and the availability of new antibiotics. The aim of these guidelines, which cover both native valve and prosthetic valve endocarditis, is to standardize the initial investigation and treatment of IE. An extensive review of the literature using a number of different search criteria has been carried out and cited publications used to support any changes we have made to the existing guidelines. Publications referring to in vitro or animal models have only been cited if appropriate clinical data are not available. Randomized, controlled trials suitable for the development of evidenced-based guidelines in this area are still lacking and therefore a consensus approach has again been adopted for most recommendations; however, we have attempted to grade the evidence, where possible. The guidelines have also been extended by the inclusion of sections on clinical diagnosis, echocardiography and surgery.

Laboratory Diagnosis of Infective Endocarditis

“…The American Heart Association and the European Society of Cardiology recommend at least three sets of blood cultures collected from different venipuncture sites, with at least 1 h between the first and last draw (1,6). The British Society for Antimicrobial Chemotherapy (BSAC) recommends collection of two sets of blood cultures within 1 h of each other in patients with suspected endocarditis and acute sepsis and three sets of blood cultures spaced Ն6 h apart in cases of suspected subacute or chronic endocarditis (9). Conventionally, three sets of blood cultures, with each set including one aerobic and one anaerobic bottle, are collected.…”

“…The Clinical and Laboratory Standards Institute (CLSI) guidelines recommend terminal subculture to chocolate agar if blood cultures are negative at 5 days and an endocarditis diagnosis is under consideration (15). However, current evidence fails to support the usefulness of blind subculture, and this practice is not recommended in the BSAC guidelines (9,16). Fungal endocarditis is most commonly caused by Candida species, which should grow in routine blood cultures.…”

“…For cases in which antibiotics have been administered prior to blood culture collection, consideration may be given to stopping antibiotics if possible, with recollection of blood cultures after an antibiotic-free period. While 7 to 10 days off antimicrobial therapy has been recommended, the ideal length of time needed off therapy is unknown and may vary depending on the infecting organism, antibiotics used, and duration of therapy administered (9). Nevertheless, many patients with bacterial endocarditis receive antibiotics without blood cultures having been appropriately collected, obfuscating subsequent microbiologic diagnosis of endocarditis.…”

“…Microorganism identification by culture of cardiac vegetations is considered a pathological criterion, meeting the definition of definite endocarditis by the modified Duke criteria; accordingly, excised valves are often submitted to the microbiology laboratory for culture and Gram stain (1). Current recommendations for the diagnosis of endocarditis also recommend culture of valvular tissue, with culture results being used to direct the duration of postoperative antimicrobial therapy (1,6,9). Gram stain of tissue processed in the microbiology laboratory may be more sensitive than histopathological Gram stain of tissue sections, 81% versus 67% in one study; however, in 10% of cases, the histopathology Gram stain detected organisms while the microbiology Gram stain was negative (17).…”

Treatment of native valve endocarditis due to coagulase negative staphylococci, complicated by a drug reaction with eosinophilia and systemic symptoms (DRESS syndrome)

“…6 However, the British Society for Antimicrobial Chemotherapy documents treatment of individual cases successfully with oral linezolid and recommends oral linezolid as oral bioavailability is close to that achieved with intravenous administration. 7 They do not however recommend it as monotherapy. IV gentamicin was therefore combined with linezolid in treatment of this patient, but had to be omitted after 3 days due to the development of an itchy rash during administration as recommended by the European Society of Cardiology.…”