Which of the following organisms is associated with HACEK group infections?

The HACEK group refers to a set of fastidious gram-negative bacteria that are known to cause endocarditis, particularly in patients with pre-existing heart conditions. The acronym HACEK stands for Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella. Among these, Haemophilus aphrophilus is one of the organisms included in the HACEK group.

When considering Haemophilus aphrophilus, it is important to note that it is part of the normal flora of the oral cavity and is associated with infections that typically occur following dental procedures or due to poor dental hygiene. These infections tend to have particular importance because they can be difficult to identify due to the fastidious nature of the bacteria, which can require specific culture conditions for growth.

In contrast, the other organisms listed in the choices do not belong to the HACEK group. Staphylococcus aureus is a common cause of skin and soft tissue infections, osteomyelitis, and also bacterial endocarditis, but it is not part of the HACEK group. Escherichia coli is primarily associated with gastrointestinal infections and urinary tract infections rather than endocarditis. Streptococcus pneumoniae is