Which Haemophilus species is most commonly associated with endocarditis?

The Haemophilus species most commonly associated with endocarditis is H. aphrophilus. This organism is part of a group of bacteria known to cause infective endocarditis, particularly in individuals with pre-existing heart conditions or risk factors. H. aphrophilus, also known as Aggregatibacter aphrophilus, is often found in the normal flora of the human mouth and respiratory tract, which facilitates its potential to enter the bloodstream during dental procedures or infections in the oral cavity, contributing to the development of endocarditis.

H. influenzae is primarily known for causing respiratory tract infections and invasive diseases such as meningitis, rather than endocarditis. H. ducreyi is primarily associated with chancroid, a sexually transmitted infection, and does not have a significant link to endocarditis. H. haemolyticus has been implicated in various infections, but it is less commonly associated specifically with endocarditis compared to H. aphrophilus. Thus, the association of H. aphrophilus with endocarditis underscores its role in this serious condition.