HACEK organism: Difference between revisions
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==Overview== | ==Overview== | ||
HACEK organisms is a group of fastidious, slow-growing, pleomorphic [[Gram negative]] bacilli which typically colonize the oropharynx and account for about 3% of cases of [[endocarditis]].<ref name="pmid2346159">{{cite journal | author = Steckelberg JM, Melton LJ, Ilstrup DM, Rouse MS, Wilson WR | title = Influence of referral bias on the apparent clinical spectrum of infective endocarditis | journal = Am. J. Med. | volume = 88 | issue = 6 | pages = 582–8 | year = 1990 | month = June | pmid = 2346159 | doi = | url = | issn = }}</ref> HACEK refers to the initials of organisms including: | HACEK organisms is a group of fastidious, slow-growing, pleomorphic [[Gram negative]] bacilli which typically colonize the oropharynx and account for about 3% of cases of [[endocarditis]].<ref name="pmid2346159">{{cite journal | author = Steckelberg JM, Melton LJ, Ilstrup DM, Rouse MS, Wilson WR | title = Influence of referral bias on the apparent clinical spectrum of infective endocarditis | journal = Am. J. Med. | volume = 88 | issue = 6 | pages = 582–8 | year = 1990 | month = June | pmid = 2346159 | doi = | url = | issn = }}</ref> HACEK refers to the initials of organisms including: | ||
Revision as of 00:47, 1 May 2013
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Template:GCC
Overview
HACEK organisms is a group of fastidious, slow-growing, pleomorphic Gram negative bacilli which typically colonize the oropharynx and account for about 3% of cases of endocarditis.[1] HACEK refers to the initials of organisms including:
- Aggregatibacter actinomycetemcomitans (formerly Actinobacillus actinomycetemcomitans), Aggregatibacter aphrophilus (formerly Haemophilus aphrophilus and Haemophilus paraphrophilus)
Pathophysiology
All of these organisms are part of the normal oropharyngeal flora which grow slowly, prefer a carbon dioxide–enriched atmosphere and share an enhanced capacity to produce endocardial infections, especially in young children.
In addition to valvular infections in the heart, these organisms can also produce other infections such as bacteremia, abscesses, peritonitis, otitis media, conjunctivitis, pneumonia, peritonitis, arthritis and osteomyelitis, and periodontal infections.
Epidemiology and Demographics
Collectivelly, they account for 5-10% of cases of infective endocarditis involving native valves and are the most common gram-negative cause of endocarditis among people who do not use IV drugs.
Diagnosis
Laboratory Studies
Because of their fastidious growth requirements, they have been a frequent cause of culture-negative endocarditis. Culture negative refers to its inability to produce a colony on regular agar plates, this is because they are fastidious (require a specific nutrient).
Treatment
The treatment of choice for HACEK organisms in endocarditis is ceftriaxone, a cephalosporin antibiotic. The dose is 2 g I.V. daily as a single dose for 4 weeks.