What type of infections are associated with the HACEK group of organisms?

The HACEK group of organisms refers to a specific ensemble of bacteria that includes Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella. These bacteria are known to be part of the normal flora in the human mouth and upper respiratory tract but can act as opportunistic pathogens.

The primary association of the HACEK group is with endocarditis, which is an infection of the inner lining of the heart chambers and valves. In particular, these organisms are often implicated in cases of culture-negative endocarditis, where the standard cultures do not yield any growth. The characteristic feature of these organisms is their fastidious nature, requiring specialized culture techniques for identification, which is why they can frequently go undetected in routine blood cultures.

This connection to endocarditis is crucial for clinical decision-making, as identifying these organisms is vital for appropriate treatment of patients presenting with valvular heart disease or other cardiac conditions that might predispose them to such infections.