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Infective endocarditis caused by HACEK microorganisms
M Das1, A D Badley, F R Cockerill
1Division of Cardiology, Mayo Clinic, Rochester, Minnesota 55905, USA.
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.
Insights
Infective endocarditis caused by HACEK organisms, though rare, has a favorable prognosis. Prompt diagnosis and treatment, often involving beta-lactam therapy, lead to high survival rates.
Area of Science:
- Infectious Diseases
- Cardiology
- Microbiology
Background:
- The HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella) group comprises fastidious gram-negative bacteria.
- These organisms are an uncommon cause of infective endocarditis, accounting for about 3% of cases.
Purpose of the Study:
- To analyze the clinical characteristics, management, and outcomes of infective endocarditis caused by HACEK organisms.
- To assess the incidence and prognostic factors of HACEK endocarditis in a defined population.
Main Methods:
- Retrospective case series analysis of 45 patients diagnosed with HACEK endocarditis.
- Review of clinical presentation, diagnostic methods (blood cultures, echocardiography), treatment regimens, and patient outcomes.
Main Results:
- The incidence of HACEK endocarditis was 0.14 per 100,000 person-years.
- Common symptoms included fever, splenomegaly, new murmurs, and microvascular phenomena, with a median symptom duration of 2 weeks to 6 months.
- Surgery was performed in 24% of patients within the first month; overall survival was 87%.
Conclusions:
- HACEK endocarditis, despite its challenging diagnosis, is associated with a favorable prognosis.
- Early diagnosis and appropriate antimicrobial therapy, often with beta-lactams, are crucial for successful management and improved survival.
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