The HACEK group includes weakly virulent, gram-negative organisms that primarily cause endocarditis.
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; about 5% of endocarditis cases are due to this group, making them the most common causes of gram-negative bacilli endocarditis. The group consists of
Antibiotic sensitivities differ among species, so treatment should be directed by susceptibility testing. However, increasing β-lactam resistance has made ceftriaxone and ampicillin/sulbactam the current antibiotics of choice.
Last full review/revision February 2014 by Larry M. Bush, MD; Maria T. Perez, MD
Content last modified March 2014