title: Aerococcus christensenii native aortic valve subacute bacterial endocarditis (SBE) presenting as culture negative endocarditis (CNE) mimicking marantic endocarditis.
abstract: This is a case report of an adult who presented with apparent culture negative endocarditis (CNE) thought to be marantic endocarditis due to a B-cell lymphoproliferative disorder. This was a most perplexing case and was eventually diagnosed as subacute bacterial endocarditis (SBE) due to a rare slow growing organism. Against the diagnosis of SBE was the lack of fever, hepatomegaly, peripheral manifestations and microscopic hematuria. Also, against a diagnosis of SBE was another explanation for the patient's abnormal findings, e.g., elevated ferritin levels, elevated α1/α2 globulins on SPEP, an elevated alkaline phosphatase, flow cytometry showing B-lymphocytes expressing CD5, and a bone lesion in the right iliac. Findings compatible with both SBE and marantic endocarditis due to a B-cell lymphoproliferative disorder included an elevated ESR, and splenomegaly. Blood cultures eventually became positive during hospitalization. We report a case of native aortic valve (AV) subacute bacterial endocarditis (SBE) due to Aerococcus christensenii mimicking marantic endocarditis due to a B-cell lymphoproliferative disorder. To the best of our knowledge, this is the first reported case of native AV SBE due to A. christensenii presenting as marantic endocarditis.
authors.affiliation: Infectious Disease Division, Winthrop-University Hospital, Mineola, NY, USA.
authors.forename: Anita
authors.initials: A
authors.lastname: Jose
authors.affiliation: Infectious Disease Division, Winthrop-University Hospital, Mineola, NY, USA; State University of New York, School of Medicine, Stony Brook, NY, USA. Electronic address: bacunha@winthrop.org.
authors.forename: Burke A
authors.initials: BA
authors.lastname: Cunha
authors.affiliation: Infectious Disease Division, Winthrop-University Hospital, Mineola, NY, USA; State University of New York, School of Medicine, Stony Brook, NY, USA.
authors.forename: Natalie C
authors.initials: NC
authors.lastname: Klein
authors.affiliation: Microbiology Laboratory, Winthrop-University Hospital, Mineola, NY, USA.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Schoch
mesh_terms: D056570:Aerococcus; D001021:Aortic Valve / Q000382:microbiology; D003937:Diagnosis, Differential; D059905:Endocarditis, Non-Infective / Q000175:diagnosis; D004698:Endocarditis, Subacute Bacterial / Q000175:diagnosis*; D005334:Fever; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: B-cell lymphoproliferative disorder; Culture negative endocarditis (CNE); Elevated ferritin levels; Endocarditis differential diagnosis; Marantic endocarditis; Mimics of endocarditis; Slow growing Gram positive cocci; Viridans streptococcal endocarditis mimics