HACEK endocarditis: a review

Introduction: The HACEK group, referring to Haemophilus spp., Aggregatibacter actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae, is a rare cause of infective endocarditis (IE). It causes the majority of Gram-negative endocarditis cases and has an excellent prognosis and simple management if properly identified. However, delay in diagnosis and associated complications can render the infection fatal. Areas Covered: Over the past few decades, there have been tremendous advancements in understanding the manifestations and progression of HACEK endocarditis (HE). This review tackles the epidemiology of HE, the microbiological characteristics of each organism in the HACEK group, the methods used to diagnose HE, the clinical manifestations, complications, and mortality of patients with HE, as well as the recommended treatment and preventive methods. Expert Commentary: The lack of robust randomized controlled trials in diagnosis and treatment of HE makes it difficult to determine the optimal management of such infections. Nevertheless, advancements in culturing methods have shown progress in isolating and identifying these fastidious organisms. Positive blood cultures for any of the HACEK organisms in the setting of no definite focus of infection is highly suggestive of HE. In such cases, treatment with ceftriaxone or a fluoroquinolone, even without obtaining antibiotic susceptibilities, should be initiated. Moreover, the decision to proceed with surgical intervention should be individualized. As is the case for other IE, HE requires the collaboration of a multidisciplinary team consisting of the infectious disease specialist, cardiologist, cardiothoracic surgeon, and the microbiologist.