Viridans group streptococci (VGS), which are commensal flora in the oral cavity, can act as opportunistic pathogens causing serious infections such as infective endocarditis (IE). Species identification of these organisms is difficult because of variability in phenotypic traits among strains of the same species.

Case presentation:

We report a case of endocarditis in a 64-year-old male patient caused by , which was identified by 16S rRNA gene sequencing. is a commensal of the oral cavity and rarely causes disease. This is the second report of IE caused by


Molecular methods are necessary to ascertain the identity of VGS strains, particularly those that rarely cause human disease.


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