Endocarditis Caused by Nontypeable Streptococcus pneumoniae.

The Streptococcus pneumoniae capsule is regarded as indispensable in bacteremia. We report an infant with a ventricular septal defect and infective endocarditis caused by nontypeable S. pneumoniae. In-depth investigation confirmed a deficient capsule yet favored pneumococcal fitness for causing infective endocarditis, rather than a host immune disorder, as the cause of infective endocarditis in this case.