The HACEK group (Haemophilus species, Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae) includes weakly virulent, gram-negative organisms that primarily cause endocarditis. Treatment is with antibiotics.
The HACEK group of nonmotile, gram-negative bacilli or coccobacilli contains a number of minimally pathogenic, slow-growing, fastidious genera. Their primary pathology is endocarditis in susceptible people; up to 5% of native valve endocarditis cases are due to this group (1), making them the most common causes of gram-negative bacilli endocarditis.
The HACEK group consists of
Haemophilus species (H. parainfluenza, H. aphrophilus, and H. paraphrophilus), which may cause respiratory infections or, less commonly, endocarditis
Aggregatibacter actinomycetemcomitans, which usually occurs with A. israelii in actinomycosis
Cardiobacterium hominis
Eikenella corrodens, which usually occurs in human bite wounds, endocarditis (often in people who inject drugs), brain and visceral abscesses, osteomyelitis, respiratory infections (including empyemas), uterine infections related to intrauterine devices, and mixed soft-tissue infections
Reference
1. Baddour LM, Wilson WR, Bayer AS, et al. Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications: A Scientific Statement for Healthcare Professionals From the American Heart Association [published correction appears in Circulation. 2015 Oct 27;132(17):e215] [published correction appears in Circulation. 2016 Aug 23;134(8):e113] [published correction appears in Circulation. 2018 Jul 31;138(5):e78-e79]. Circulation. 2015;132(15):1435-1486. doi:10.1161/CIR.0000000000000296
