Infective endocarditis by a rare and fastidious agent: Abiotrophia defectiva

Abstract

Abiotrophia defectiva is a nutritional variant streptococcus, with affinity for endovascular structures that cannot be cultured on non-supplemented media, leading to a delay in diagnosis. This case describes a 36-year-old woman with a previously known bicuspid aortic valve that presented with asthenia, myalgias and anorexia with 2-month onset. On admission, we documented fever and a systolic murmur. Transthoracic echocardiography revealed an oscillating mass attached to the aortic valve. The patient was admitted with a possible diagnosis of infective endocarditis. Later, blood cultures were positive for A. defectiva Due to severe aortic regurgitation and congestive heart failure, she underwent surgical aortic valve replacement. After 6 weeks of antimicrobial therapy, the patient experienced full recovery. Despite of its rarity, A. defectiva endocarditis is associated with significant morbidity with mortality and physicians must have a high level of suspicion to ensure a prompt diagnosis and provide the appropriate treatment.

Keywords: cardiothoracic surgery; heart failure; infections; valvar diseases.

Figure 1

Transoesophageal echocardiography. Mid-oesophageal aortic valve short axis (30°) revealing a severely infiltrated bicuspid aortic valve (*); notice the right non-coronary cusp fusion pattern. IAS, interatrial septum; LA, left atrium; LCC, left coronary cusp of the aortic valve; NCC, non-coronary cusp of the aortic valve; RA, right atrium; RCC, right coronary cusp of the aortic valve.

Figure 2

Transoesophageal echocardiography. Mid-oesophageal aortic valve long axis view (120°) revealing severely infiltrated aortic valve cusps with an attached vegetation (*). AA, ascending aorta; LA, left atrium; LVOT, left ventricular outflow tract.