Infectious endocarditis cause by Abiotrophia defectiva

We report a case of 61-year-old man presented with progressive dyspnea for 5 month followed by respiratory failure. Transthoracic echocardiogram revealed bacterial vegetation, rheumatic change mitral valve and destruction of the aortic valve. Initial hemoculture reported gram-positive cocci in chain for two specimens and its resistance to penicillin and vancomycin. Daptomycin was administered as a primary drug, but the latter hemoculture was identified as Abiotrophia defectiva. Infectious endocarditis caused by A. defectiva was diagnosed, he was treated with diuretic and penicillin G. Aortic valve replacement and valvulopathy of mitral valve was done due to congestive heart failure and large vegetation. After operation and total penicillin G 4 weeks, he improved and was discharged from the hospital. Infectious diseases caused by A. defectiva are extremely rare, and identification of this pathogen is important, as its bacterial characteristics require proper attention. (J Infect Dis Antimicrob Agents 2012;29:21-5.) Note: This case was presented in the Interhospital Case Conference on Infectious Diseases (ICCID), 18 August 2011, Bangkok, Thailand. INTRODUCTION Abiotrophia species, first described as nutritionally variant (deficient) streptococci in 19611, were originally discovered as small satellite colonies around coagulasenegative bacteria or with supplementation of complex media with cysteine or pyridoxal.2 Taxonomic studies of the Abiotrophia spp. concluded that this group of organisms should be reclassified separately into Abiotrophia defectiva and Granulicatella adiacens, G. balaenopterae, and G. elegans.3 Although Abiotrophia/Granulicatella are parts of the normal flora of the oral cavity, the genitourinary tract, and the intestinal tract, the pathogenic potential of these organisms has been well established. They have been estimated to cause approximately 5-6% of microbiologically proven cases of endocarditis4, Division of Infectious Diseases, Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand. Reprint request: Somnuek Sungkanuparph, M.D., Professor of Medicine, Division of Infectious Diseases, Department of Medicine, Ramathibodi Hospital, 270 Rama 6 Road, Bangkok 10400, Thailand. Email: [email protected]