Sanguinis

S. sanguinis, formerly spelled sanguis, is among the first colonizers of the tooth surface, forming the pellicle on which later plaque organisms including S. mutans accumulate. Transient bacteraemia from chewing, brushing, or dental procedures is common; in a patient with a previously damaged or prosthetic valve, the organism binds to the sterile platelet-fibrin thrombus that forms over the injured endothelium and establishes a vegetation. The resulting subacute endocarditis evolves over weeks with low-grade fever, fatigue, anorexia, weight loss, anaemia, splenomegaly, and immune complex phenomena — Osler nodes, which are painful pulp lesions, Roth spots on the retina, and glomerulonephritis — while Janeway lesions, which are painless and macular, are septic emboli and more typical of acute disease. Diagnosis uses the modified Duke criteria with repeated blood cultures and echocardiography, transoesophageal being far more sensitive. It is generally highly penicillin-susceptible; treatment is four weeks of penicillin or ceftriaxone, or two weeks combined with gentamicin in uncomplicated native valve disease.