Infective Endocarditis Caused by Hacek Microorganisms

Abstract

The HACEK group of fastidious gram-negative organisms is a recognized but unusual cause of infective endocarditis, responsible for approximately 3% of cases. We report our experience with 45 cases of endocarditis caused by HACEK organisms. In Olmsted County, Minnesota, the incidence of HACEK endocarditis was 0.14 per 100,000 person-years. In patients with native valves, 33 cases occurred, and in patients with prosthetic valves, 12 cases occurred. The most common presenting symptoms were fever, splenomegaly, new or changing murmur, and microvascular phenomena. Symptoms were present in the majority of patients anywhere from two weeks to six months prior to diagnosis. Blood cultures became positive in a mean 3.375 days, and therapy with a beta-lactam alone or as part of a combination was given for anywhere between three and six weeks. Within the first month of diagnosis, surgery was performed for 13 regurgitant valves in 11 patients (24%). Echocardiography was an insensitive predictor of subsequent major arterial embolization (odds ratio, 1.33; 95% confidence interval, 0.31-5.67). The overall survival in our cohort of patients was 87%. These results confirm previous reports that HACEK endocarditis portends a favorable prognosis.

HACEK endocarditis: state-of-the-art

“…The three species A. actinomycetemcomitans, A. aphrophilus, and A. segnis are the second most common cause of HACEK endocarditis, found in 26 (34%) of the 77 cases of HACEK endocarditis enrolled within the ICE prospective cohort study [7], and 16 out of 45 (36%) cases of HACEK endocarditis reported from the Mayo Clinic [2]. The association between Aggregatibacter spp.…”

“…parainfluenzae is the most common cause of HACEK endocarditis, found in 28 (36%) of the 77 cases of HACEK endocarditis enrolled within the International Collaboration on Endocarditis (ICE) prospective cohort study during years 2000-2006 [7], and 12 out of 45 (27%) cases of HACEK IE reported from the Mayo Clinic in Rochester, during years 1970-1992 [2]. The association between H. parainfluenzae bacteremia and IE is strong, with a positive predictive value (PPV) for the diagnosis of IE estimated at 55% (10/18) [4].…”

“…are the third most common agents responsible for HACEK endocarditis, found in 11 (14%) of the 77 cases of HACEK endocarditis enrolled within the ICE prospective cohort study [7], and 12 out of 45 (27%) cases of HACEK endocarditis reported from the Mayo Clinic [2]. Although C. hominis is by far the most common Cardiobacterium species involved, a few cases of C. valvarum endocarditis have been reported since it was first identified in a patient with bicuspid aortitis and ruptured mycotic cerebral aneurysm, in 2004 [31].…”

“…Its association with endocarditis is rather weak, as i) this bacteria was responsible for only ~5% of all HACEK endocarditis reported from the Mayo clinic [2], and in the ICE-prospective cohort study [7]; ii) the PPV of E. corrodens bacteremia for the diagnosis of endocarditis is the lowest among all HACEK bacteria (none of 11 consecutive cases of E. corrodens bacteremia was related to endocarditis in one study) [4]; iii) E. corrodens is involved in a broad spectrum of infectious diseases, including localized infections of the head and neck, upper or lower tract respiratory infections, subcutaneous abscesses, cellulitis, and osteomyelitis [39]. Interestingly, these latter have been especially reported following clenched fist injuries or human bites, due to the traumatic inoculation of E. corrodens originating from the oral microbiota [40].…”

Classification, Identification, and Clinical Significance of Haemophilus and Aggregatibacter Species with Host Specificity for Humans

“…The so-called HACEK group of fastidious Gram-negative organisms is a recognized but unusual cause of infective endocarditis, responsible for 1.4 to 3% of cases (209,210). The group was originally described to encompass Haemophilus species, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae (211).…”