A Case of Endocarditis: When Three Equals One

Abstract

400 A32 year-old male smoker presented to the emergency room with increasing breathlessness over two weeks. Past history was unremarkable, including no history of rheumatic fever, heart murmurs, intravenous drug use or recent invasive procedures. Oral hygiene was poor, and an aortic insufficiency murmur was heard on physical examination. Blood work revealed leukocytosis (white blood cells=18.3×109/L), hyperglycemia (serum blood glucose=17.8 mmol/L) and ketoacidosis. A chest radiograph displayed cardiomegaly, pulmonary edema and bilateral pneumonia. Serial electrocardiograms showed ST elevation in the precordial leads and troponin I was 4 μg/L. Two initial blood cultures grew coagulase-negative staphylococci (CNS). The patient was treated with levofloxacin and vancomycin, along with usual therapy for hyperglycemia, congestive heart failure and acute coronary syndrome. A transesophageal echocardiogram (TEE) revealed severe aortic insufficiency, an aortic root abscess and a large cauliflower-shaped vegetation extending into the aortic valve. The patient underwent urgent aortic valve replacement and pericardial closure of the abscess. Two preoperative blood cultures each grew Staphylococcus warneri and Staphylococcus haemolyticus, as speciated by VITEK (bioMerieux, USA). Intraoperative aortic valve and pericardial fluid cultures, as well as two postoperative blood cultures, grew Staphylococcus epidermidis and S warneri, which were also speciated by VITEK. The automated antibiograms produced by VITEK for the various isolates differed, which is consistent with a polymicrobial endocarditis. The patient was treated with vancomycin, rifampin and gentamicin (to which all isolates were sensitive), but worsened clinically and demonstrated persistent fever. What is your diagnosis? What would you recommend?