An Unusual Case of Neisseria flavescens/subflava Group Tricuspid Valve Endocarditis in a Patient With Previously Treated Methicillin-Resistant Staphylococcus aureus Endocarditis.

Infective endocarditis (IE) is classified as an infection of any cardiac valve or endocardial surface and is often associated with high morbidity and mortality. Certain bacteria such as gram-positive cocci and viridans group streptococci have high predilection for both naïve and damaged cardiac valvular tissues, accounting for the majority of IE cases. In very infrequent instances, gram-negative bacteria (GNB), more specifically non-meningococcal, non-gonococcal GNB, have been shown to cause IE. The following is a case of a young male diagnosed with Neisseria flavescens/subflava tricuspid valve endocarditis after being previously treated for Methicillin-resistant Staphylococcus aureus (MRSA) endocarditis.