Infective Endocarditis: Most common infective microorganisms

[lee-usmle]

Remembering the most common infectious microorganism that cause a particular infective endocarditis can be a hassle at times.

Here's a mnemonic that can help
natiVe valve ---> Streptococcus Viridans
Prosthetic valve ---> Staphylococcus ePidermidis
Drug Addicts ---> Staphylococcus Aureus

Please note that Viridans group of streptococci include the following:
S. mitis, S. mutans, S. sanguis, and S. salivarius. S. mutans is famous after dental procedures.

[S.Martin]

That's really nice, it can help us solve many questions.

Just want to remind you that in prosthetic valves epidermidis is the most common in the acute setting but later on viridans becomes the most common. Well you can think of that valve as though it has become native after a while

[YoramFishke]

Streptococcus viridans is the most common over all cause in native valves because it's usually subacute infection. However, for acute infection, which is more devastating to the heart with rapid onset of fever then in that case Staphylococcus aureus is the most common cause.