A Rare Case ofStreptococcus alactolyticusInfective Endocarditis Complicated by Septic Emboli and Mycotic Left Middle Cerebral Artery Aneurysm

Abstract

To date, S. alactolyticus endocarditis complicated by middle cerebral artery aneurysm has not been reported. We describe the case of a 65-year-old female with a history of hypertrophic cardiomyopathy with left ventricular outflow tract obstruction presenting with confusion and a apical holosystolic murmur. Angiography of the brain identified new bilobed left middle cerebral artery aneurysm. Serial blood cultures grew S. alactolyticus, and aortic and mitral valve vegetation were discovered on transesophageal echocardiography. The patient was treated with antimicrobial therapy, mitral and aortic valve replacements, and microsurgical clipping of cerebral aneurysm. This case serves to highlight the pathogenicity of a sparsely described bacterium belonging to the heterogenous S. bovis complex.

The Road to Infection: Host-Microbe Interactions Defining the Pathogenicity of Streptococcus bovis/Streptococcus equinus Complex Members

“…About 20% of all SB bacteremia cases have an association with underlying biliary origin of which 59% was isolated from polymicrobial infections, most frequently in combination with Escherichia coli and Enterococcus spp (Corredoira et al, 2014 ). The specific species associations with hepatobiliary disorders vary for SGP (10–83%) and SL (25–60%) followed by SGG (2–35%) and rarely for SII, SGM and S. alactolyticus (Beck et al, 2008 ; Romero et al, 2011 ; Lazarovitch et al, 2013 ; Corredoira et al, 2014 ; Sheng et al, 2014 ; Toepfner et al, 2014 ; Almeida et al, 2016 ). In rare cases, SB was obtained from cerebrospinal fluid and blood culture of patients with liver cirrhosis that developed bacterial meningitis (Barahona-Garrido et al, 2010 ).…”

A rare case of bacterial infective endocarditis caused by Streptococcus alactolyticus

“…Human reports of S. alactolyticus infection are exceedingly rare. S. alactolyticus was reported as a causative agent in a patient with IE complicated by septic emboli (14). Another fatal case of fulminant neonatal sepsis caused by this pathogen was also reported (15).…”

Unusual cause of severe diabetic ketoacidosis precipitated by Streptococcus bovis/equinus (SBSEC) bacteremia: Case report and review of literature

“…Human infections by Streptococcus alactolyticus are extremely rare and often virulent as evidenced by few human cases described in literature. Recently, Almeida et al described a case of infective endocarditis complicated by septic emboli [ 4 ] and Toepfner et al described a fatal case of fulminant neonatal sepsis caused by this pathogen [ 6 ].…”

“…The Streptococcal bovis/Streptococcal equinus complex (SBSEC) compromises a highly diverse group of bacteria including commensal colonizers of the human and animal gastrointestinal tract and opportunistic pathogens [ 3 ]. Associated bacteremia, infective endocarditis, neonatal meningitis, fulminant neonatal sepsis and chorioamnionitis have been reported in the literature [ [4] , [5] , [6] , [7] ]. In the new taxonomy of SBSEC, Streptococcus alactolyticus was included in SBSEC as phenotypically indistinguishable and an earlier synonym of S. intestinalis , grouped under Salivarius group of Streptococcal viridans species based on phenotypic characteristics [ 8 ].…”