Clinical microbiology Actinomyces israelii endocarditis misidentified as “Diptheroids” Amesh A. Adalja * , Emanuel N. Vergis Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, University of Pittsburgh, 3550 Terrace Street, Pittsburgh, PA 15261, USA article info Article history: Received 24 November 2009 Received in revised form 30 April 2010 Accepted 5 May 2010 Available online 21 May 2010 Keywords: Actinomyces Endocarditis Diptheroids Cornyebacteria abstract Actinomyces is a rare cause of endocarditis, however misidentification as Cornyebacteria often hampers the diagnosis. Ó 2010 Elsevier Ltd. All rights reserved. An otherwise healthy 87 year old man presented to the Emergency Department with a 2 month history of functional decline, excessive fatigue, weight loss, appetite loss, and intermittent fevers. There was no report of dysuria, dyspnea, rash, diarrhea, headache, or abdominal pain present. The patient had been evaluated as an outpatient for these complaints and a diagnosis had not been reached. The patient was admitted for further diagnostic testing. The patient’s past medical history was significant for prostate cancer and polymyalgia rheuma- tica for which he had received steroids in the past (he had been off steroids for approximately one year prior to admission and had a negative temporal artery biopsy). The physical examination was largely unrevealing and did not reveal any stigmata of endocarditis including cardiac murmur, Janeway lesions, or Osler’s nodes. His neurological exam was significant for tangential speech, poor recall, and poor comprehension. Oral examination did not reveal any evidence of infection. Blood cultures were drawn secondary to the report of intermittent fevers. Laboratory studies were unremarkable except for a C-reactive protein level of 7.48 mg/dl. MRI imaging of the brain revealed only cerebral atrophy. The working diagnosis, at that time, was large vessel vasculitis for which subsequent MRI/MRA investigation failed to reveal any evidence. Subsequently, two sets of blood cultures returned positive for gram positive rods and an infectious diseases consultation was sought. Given the history of intermittent fevers coupled with the high degree of bacteremia, infective endocarditis was suspected and intravenous vancomycin was begun and echocardiography was requested. Within 48 h, the patient’s cognition had markedly improved, speech became coherent, and comprehension improved. The gram positive rod was initially identified via standard bacterial culture as a Cornyebacteria species (“diptheroids”) but after subsequent growth and testing utilizing the RapID ANA II System (remel) the isolate was identified as Actinomyces israelii. Therapy was changed to intravenous penicillin. Subsequent blood cultures demonstrated clearance of the bacteremia. A trans- esophageal echocardiogram, obtained after a transthoracic echocar- diogram failed to reveal any vegetations, demonstrated an echodensity consistent with a vegetation on the mitral valveda component of the major criteria of the Duke Criteria for diagnosis of endocarditis. The patient completed a six-week course of intravenous penicillin followed by six months of oral penicillin. Upon further questioning, the patient related a history of dental cleaning within the three months preceding his hospitalization. Dental radiography did not reveal any evidence of current odontogenic infection. A repeat echocardiogram 4 months later demonstrated resolution of the vegetation. We suspect that the patients mental clouding reflecting a mild encephalopathy resulting from prolonged bacteremia super- imposed on age-related cerebral atrophy. Endocarditis due to Actinomyces species has been reported several times in the literature [1e4]. The case fatality rates have been reported at 46%, possibly reflecting a lack of surgical intervention in early reports [2,4]. No distinguishing clinical features have been discovered [1]. Often, as in our case, blood isolates are initially described as being Cornyebacteria or “diptheroids” [3]. Most patients present in a subacute fashion and lack stigmata of endocarditis and species other than A. israelii have been identified [1]. The diagnosis of Actinomyces endocarditis relies on isolation of the organism, however the tendency * Corresponding author. Tel.: þ1 724 822 2035; fax: þ1 724 586 6848. E-mail address: ameshaa@aol.com (A.A. Adalja). Contents lists available at ScienceDirect Anaerobe journal homepage: www.elsevier.com/locate/anaerobe 1075-9964/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.anaerobe.2010.05.003 Anaerobe 16 (2010) 472e473