What conditions cause mitral valve infection?

Bacteria in blood. Bacteria in the blood attach to the valve and then there is infection. If the valve is normal this is not likely to happen. Bacteria can enter the blood stream from such routine things such as cleaning your teeth. Most of the time this causes no problem unless the bacteria attach to a foreign body like a replaced valve or a damaged valve. More likely if your gums are infected., .
Mitral valve . Any condition that allows bacteria to settle on a deformed valve such as dental work abdominal infections or skin infections ( staph or streptococcus or enterococcus ).