[Infective endocarditis by Abiotrophia defectiva diagnosed by mass spectrometry (MALDI-TOF MS) in Argentina].

We report the case of a 63-year-old woman with congestive heart failure due to a bicuspid aortic valve and severe aortic stenosis. The patient had a febrile syndrome with positive blood cultures for Abiotrophia defectiva, Transesophageal echocardiogram revealed the presence of paravalvular abscess, which was treated by a successful valve replacement. The patient received appropriate antibiotic therapy with intravenous vancomycin, leading to a successful response. The use of MALDI-TOF MS as a rapid and specific method for the microbiological diagnosis is discussed in the following report.