Case Report: Streptococcus alactolyticus as a Rare Pathogen of Mitral Endocarditis.

Mattia Vinciguerra,Antonio De Bellis,Gloria Taliani,Valeria Santamaria,Mizar D'Abramo,Silvia Romiti,Ernesto Greco,Giuseppe Sangiorgi,Gianmarco Toto

doi:10.3389/fcvm.2021.648213

Abstract

Streptococcus bovis/Streptococcus equinus complex (SBSEC) is a group of non-enterococcal group D Streptococci that colonizes both humans and animals. Due to gastrointestinal disease, they can switch in opportunistic pathogens passing through intestinal mucosal barrier and may cause bacteremia and distant organs damage. Despite infective endocarditis (IE), extra-cardiac manifestations of organs damage include osteoarticular infections, meningitis, and biliary infections among others; moreover, the association with colonic pathological lesions has been largely described. Streptococcus alactolyticus as a species included in SBSEC may share pathophysiological similarities, although it represents an extremely rare cause of distant organ infections, being reported in literature as causative agent of IE in only two other cases. We describe a case of 69-year-old male admitted to our institution due to mild–moderate dyspnea and fever, affected by cervico-brachialgia for 3 weeks. Streptococcus alactolyticus was identified as causative agent of IE on the mitral valve, causing severe regurgitation.

Highlights

Every year, between two and six people per every hundred-thousand inhabitants worldwide suffer from infective endocarditis (IE) [1]
The transthoracic echocardiogram (TTE) diagnosed a severe mitral regurgitation (MR) due to IE; it was confirmed by transesophageal echocardiogram (TEE), which showed two vegetations on the atrial face of mitral valve, sized 11 × 10 mm on the posterior leaflet and 7 × 5 mm on the anterior leaflet (Figure 1)
The Streptococcus bovis/Streptococcus equinus complex (SBSEC) is a group of non-enterococcal group D Streptococci that colonizes the gastrointestinal tract as commensal in humans and animals and is involved in food fermentation [4]

Summary

Introduction

Between two and six people per every hundred-thousand inhabitants worldwide suffer from infective endocarditis (IE) [1]. When IE is not properly treated, significant complications arise. The 1-year mortality average rate has not improved over the last two decades [2]. The rheumatic chronic disease remains the main cause in low-income countries. Despite the large use of antibiotics in industrialized countries, Streptococci, derived from oral microbiome, it still represents the main cause. The IE that is caused by Staphylococcus Aureus and coagulasenegative Staphylococci is found significantly on patients with intravenous drug use history, prosthetic-valve or device implanted, or somehow affected by other comorbidities. Streptococcus bovis (group D Streptococci) is more frequently found on elderly patients [1]

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Discussion

Conclusion