CP1- A case of native valve endocarditis caused by Enterococcus faecium

Abstract

Introduction

Compared to other bacteria, Enterococcus species are the third most common cause of infective endocarditis (IE), which has a high recurrence rate. Ninety-seven percent of cases of IE are caused by enterococci, particularly Enterococcus faecalis, whereas only 1% to 2% are caused by Enterococcus faecium.

Case report

A 68-year-old patient with a history of ischaemic heart disease presented with fever and lower urinary tract symptoms for two weeks. There was no evidence of infective endocarditis or urinary tract infection in the patient's past medical history. On general examination, pallor and clubbing were not present. A pansystolic murmur was noted in the mitral area radiating to the axilla.

His initial investigations showed an elevated white blood cell count (21640/mm³) with 88.4% neutrophils, C-reactive protein (CRP) of 219 mg/dL, and ESR of 65 mm in the 1st hour. After blood cultures were taken, meropenem was started. Two blood cultures were positive for Streptococcus species. Intravenous (IV) gentamicin was added. His initial urine culture showed mixed growth, and the repeat urine culture yielded no growth. There was no evidence of infection in the gastrointestinal tract.

2D echocardiogram showed mitral valve endocarditis with vegetation (11mm x 3mm). Further automated identification came as Enterococcus faecium, which was sensitive to penicillin. IV meropenem was changed to IV penicillin. Six weeks of penicillin and two weeks of gentamicin were administered. With the treatment, a clinical improvement was observed, characterized by a reduction in white blood cell count and C-reactive protein (CRP) levels. The repeat echocardiogram showed healed mitral valve vegetation.                              

Discussion

Endocarditis caused by enterococci often originates from the gastrointestinal or urinary tract, intravascular catheters, and wounds, such as burns or ulcers. Unlike in the past, according to Duke's criteria, E. faecium is no longer classified as a "typical endocarditis pathogen."

Even though E. faecium has a higher rate of resistance to vancomycin and ampicillin, which restricts treatment options; the organism isolated from our patient was sensitive to most of the antibiotics. Bloodstream infections caused by E. faecium are associated with poor outcomes and increased mortality compared to those caused by other enterococcal species, largely due to this resistance.

Early and precise identification of E. faecium infections, along with prompt initiation of appropriate antibiotic therapy, is crucial for improving patient survival.