Vancomycin-Resistant Streptococcus thoraltensis: A Case Report of Bacterial Endocarditis and Review of Literature on Infections Caused by This Pathogen

Abstract

Streptococcus thoraltensis is a rare species, part of the viridans streptococcus group, found initially in rabbits and pigs, which can be vancomycin-resistant. We present the case of a 65-year-old patient, a smoker and chronic alcohol consumer with chronic obstructive pulmonary disease (COPD) and multiple dental foci who had been diagnosed with bacterial endocarditis caused by Streptococcus thoraltensis. The particular elements of the case consisted of an atypical clinical presentation with diarrheal stools, abdominal pain, concomitant damage to the aortic and tricuspid valves, the presence of large vegetations (>2 cm), and a vancomycin-resistant strain of Streptococcus thoraltensis. The evolution of the patient was unfavorable due to septic embolisms, respiratory failure requiring orotracheal intubation, and septic and cardiogenic shock. Infections with Streptococcus thoraltensis are challenging to treat because of the severity of the clinical form it causes and the pattern of antibiotic resistance in this germ. Based on our brief review, Streptococcus thoraltensis is an extremely rare human pathogen previously described as the etiologic agent of infectious endocarditis in only one case.

Keywords: Streptococcus thoraltensis; bacterial endocarditis; large vegetation.

Figure 1

EKG: sinus rhythm, heart rate 80/min, QRS axis 90°, QS V1–V3.

Figure 2

Transthoracic echocardiography, apical 4-chamber view, reveals hyperechogenic vegetations on the tricuspid valve (the white arrow is indicating the vegetation on the aortic valve).

Figure 3

Transthoracic echocardiography, long axis parasternal section, reveals hyperechogenic vegetations on the aortic valves (the white arrow is indicating the vegetation on the aortic valve).