TY - CHAP M1 - Book, Section TI - Infections Due to the HACEK Group and Miscellaneous Gram-Negative Bacteria A1 - Barlam, Tamar F. A1 - Kasper, Dennis L. A2 - Jameson, J. Larry A2 - Fauci, Anthony S. A2 - Kasper, Dennis L. A2 - Hauser, Stephen L. A2 - Longo, Dan L. A2 - Loscalzo, Joseph PY - 2018 T2 - Harrison's Principles of Internal Medicine, 20e AB - HACEK organisms are a group of fastidious, slow-growing, gram-negative bacteria whose growth requires an atmosphere of carbon dioxide. These organisms do not grow on media routinely used for enteric bacteria (e.g., MacConkey agar). Species belonging to this group include several Haemophilus species, Aggregatibacter (formerly Actinobacillus) species, Cardiobacterium species, Eikenella corrodens, and Kingella kingae. HACEK bacteria normally reside in the oral cavity and have been associated with local infections in the mouth. They are also known to cause severe systemic infections—most often bacterial endocarditis, which can develop on either native or prosthetic valves (Chap. 123). HACEK bacteremia is strongly predictive of underlying infective endocarditis (overall positive predictive value, 60%). However, this association varies significantly by organism. For example, in one study, infective endocarditis was diagnosed in 100% of patients with Aggregatibacter actinomycetemcomitans bacteremia but in no patients with Eikenella bacteremia. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1159154182 ER -