eMedicine Specialties > Infectious Diseases > Bacterial Infections

HACEK Group Infections: Differential Diagnoses & Workup

Author: Isaac P Humphrey, MD, Assistant Professor of Internal Medicine, Uniformed Services University of the Health Sciences; Clinical Assistant Professor of Internal Medicine, Wright State University Boonshoft School of Medicine
Coauthor(s): Mirabelle Kelly, MD, Fellow, Department of Microbiology and Infectious Disease, University of Sherbrooke, Canada; Barnett Gibbs, MD, Assistant Chief, Department of Clinical Trials, Walter Reed Army Institute of Research, Infectious Disease Service, National Capital Consortium; Assistant Professor of Medicine, Uniformed Services University of the Health Sciences; Christian P Sinave, MD, Associate Professor, Department of Medical Microbiology and Infectious Diseases, University of Sherbrooke, Canada
Contributor Information and Disclosures

Updated: Nov 6, 2009

Differential Diagnoses

Actinomycosis
Brain Abscess
Fever of Unknown Origin
HACEK Group Infections
Infective Endocarditis

Other Problems to Be Considered

Marantic endocarditis
Collagen vascular disease
Neoplasm
Hypercoagulable states (lupus anticoagulant)

Workup

Laboratory Studies

  • When a HACEK organism is suspected, consider consulting a microbiologist so that special attention can be given to the blood culture specimen. Special procedures performed in the microbiology laboratory my improve the chances of isolating the organisms.2
  • Although prolonged incubation is commonly recommended in this setting, current research suggests it is the special laboratory procedures, rather than the time of incubation, that matter most.2
  • Complete cell count may show anemia with or without reactive thrombocytosis. Total white cell count may or may not be increased.
  • Other inflammatory parameters should include erythrocyte sedimentation rate, rheumatoid factor (ie, "the poor man's immune complex"), and C-reactive protein. If positive at the time of diagnosis, they can be used to monitor therapy.

Imaging Studies

  • Echocardiography
    • Echocardiography plays an important role in the diagnosis and management of endocarditis. Characteristic vegetations, abscesses, new prosthetic-valve dehiscence, or new regurgitant murmur are 4 powerful identifiers of infective endocarditis (IE) (in combination with other clinical criteria).
    • Transthoracic echocardiography (TTE) has the advantages of being fast and easy to perform. Specificity for vegetations is 98%; however, sensitivity is lower than 60%. TTE views may be inadequate in approximately 20% of the adult population because of obesity, chronic obstructive pulmonary disease, or chest-wall deformities. TTE cannot exclude infection of prosthetic valves, periannular abscess, leaflet perforation, or fistulae.
    • Transesophageal echocardiography has the advantage of having higher sensitivity for vegetations and greater specificity and sensitivity for perivalvular extension than TTE.
    • HACEK group organisms typically produce vegetations that are larger than vegetations found in IE due to other organisms, probably because of the longer mean time to diagnosis.
    • In addition to its diagnostic utility, echocardiography may play a prognostic role. Certain vegetation characteristics are associated with increased risk for embolism and mortality.12

Procedures

  • An arterial embolectomy, necessary to salvage a limb, may yield a specimen, which, by culture or histological examination, indicates the correct diagnosis.

Histologic Findings

The valvular lesions and vegetations of HACEK IE are very similar to those found in other types of subacute endocarditis, except that the larger size of the vegetations resembles those seen in fungal or staphylococcal disease.13

More on HACEK Group Infections

Overview: HACEK Group Infections
Differential Diagnoses & Workup: HACEK Group Infections
Treatment & Medication: HACEK Group Infections
Follow-up: HACEK Group Infections
References
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References

  1. Das M, Badley AD, Cockerill FR, Steckelberg JM, Wilson WR. Infective endocarditis caused by HACEK microorganisms. Annu Rev Med. 1997;48:25-33. [Medline].

  2. Baron EJ, Scott JD, Tompkins LS. Prolonged incubation and extensive subculturing do not increase recovery of clinically significant microorganisms from standard automated blood cultures. Clin Infect Dis. Dec 1 2005;41(11):1677-80. [Medline].

  3. Geraci JE, Wilson WR. Symposium on infective endocarditis. III. Endocarditis due to gram- negative bacteria. Report of 56 cases. Mayo Clin Proc. Mar 1982;57(3):145-8. [Medline].

  4. Morpeth S, Murdoch D, Cabell CH, Karchmer AW, Pappas P, Levine D, et al. Non-HACEK gram-negative bacillus endocarditis. Ann Intern Med. Dec 18 2007;147(12):829-35. [Medline].

  5. Ferreiros E, Nacinovich F, Casabé JH, Modenesi JC, Swieszkowski S, Cortes C, et al. Epidemiologic, clinical, and microbiologic profile of infective endocarditis in Argentina: a national survey. The Endocarditis Infecciosa en la República Argentina-2 (EIRA-2) Study. Am Heart J. Feb 2006;151(2):545-52. [Medline].

  6. Darras-Joly C, Lortholary O, Mainardi JL, Etienne J, Guillevin L, Acar J. Haemophilus endocarditis: report of 42 cases in adults and review. Haemophilus Endocarditis Study Group. Clin Infect Dis. Jun 1997;24(6):1087-94. [Medline].

  7. Baddour LM, Wilson WR, Bayer AS, Fowler VG Jr, Bolger AF, Levison ME, et al. Infective endocarditis: diagnosis, antimicrobial therapy, and management of complications: a statement for healthcare professionals from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, and the Councils on Clinical Cardiology, Stroke, and Cardiovascular Surgery and Anesthesia, American Heart Association: endorsed by the Infectious Diseases Society of America. Circulation. Jun 14 2005;111(23):e394-434. [Medline].

  8. Kannoth S, Thomas SV. Intracranial microbial aneurysm (infectious aneurysm): current options for diagnosis and management. Neurocrit Care. 2009;11(1):120-9. [Medline].

  9. Paterick TE, Paterick TJ, Nishimura RA, Steckelberg JM. Complexity and subtlety of infective endocarditis. Mayo Clin Proc. May 2007;82(5):615-21. [Medline].

  10. Malani AN, Aronoff DM, Bradley SF, Kauffman CA. Cardiobacterium hominis endocarditis: Two cases and a review of the literature. Eur J Clin Microbiol Infect Dis. Sep 2006;25(9):587-95. [Medline].

  11. Miró JM, del Río A, Mestres CA. Infective endocarditis in intravenous drug abusers and HIV-1 infected patients. Infect Dis Clin North Am. Jun 2002;16(2):273-95, vii-viii. [Medline].

  12. Thuny F, Di Salvo G, Belliard O, Avierinos JF, Pergola V, Rosenberg V, et al. Risk of embolism and death in infective endocarditis: prognostic value of echocardiography: a prospective multicenter study. Circulation. Jul 5 2005;112(1):69-75. [Medline].

  13. Trexler Hessen M, Abrutyn E. Gram-Negative Bacterial Endocarditis. In: Kaye D, ed. Infective Endocarditis. 2nd ed. New York, NY: Raven Press; 1992:251-64.

  14. [Guideline] Wilson W, Taubert KA, Gewitz M, Lockhart PB, Baddour LM, Levison M, et al. Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation. Oct 9 2007;116(15):1736-54. [Medline].

  15. Baron EJ, Scott JD, Tompkins LS. Prolonged incubation and extensive subculturing do not increase recovery of clinically significant microorganisms from standard automated blood cultures. Clin Infect Dis. Dec 1 2005;41(11):1677-80. [Medline].

  16. Bayer AS, Scheld WM. Endocarditis and intravascular infections. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Disease. 5th ed. Philadelphia, Pa: Churchill Livingstone; 2000:857-902.

  17. Berbari EF, Cockerill FR, Steckelberg JM. Infective endocarditis due to unusual or fastidious microorganisms. Mayo Clin Proc. Jun 1997;72(6):532-42. [Medline].

  18. Goutzmanis JJ, Gonis G, Gilbert GL. Kingella kingae infection in children: ten cases and a review of the literature. Pediatr Infect Dis J. Sep 1991;10(9):677-83. [Medline].

  19. [Guideline] Gustke CJ. A review of localized juvenile periodontitis (LJP): II. Clinical trials and treatment guidelines. Gen Dent. Nov-Dec 1998;46(6):580-7; quiz 588-9. [Medline].

  20. Gustke CJ. A review of localized juvenile periodontitis (LJP): Part I. Clinical features, epidemiology, etiology, and pathogenesis. Gen Dent. Sep-Oct 1998;46(5):491-7. [Medline].

  21. Lampe AS, Schroijen MA, Smith SJ. [Endocarditis due to Aggregatibacter (formerly: Actinobacillus) actinomycetemcomitans, a bacterium that grows in characteristic star-shaped colonies]. Ned Tijdschr Geneeskd. Apr 5 2008;152(14):827-30. [Medline].

  22. Parker SW, Apicella MA, Fuller CM. Hemophilus endocarditis. Two patients with complications. Arch Intern Med. Jan 1983;143(1):48-51. [Medline].

  23. Pereira RM, Bucaretchi F, Tresoldi AT. Infective endocarditis due to Haemophilus aphrophilus: a case report. J Pediatr (Rio J). Mar-Apr 2008;84(2):178-80. [Medline].

  24. Weinstein L, Brusch JL. Gram-Negative and Other Organisms. In: Weinstein L, Brusch JL, eds. Infective Endocarditis. New York, NY: Oxford University Press; 1996:73-122.

  25. Westling K, Vondracek M. Actinobacillus (Aggregatibacter) actinomycetemcomitans (HACEK) identified by PCR/16S rRNA sequence analysis from the heart valve in a patient with blood culture negative endocarditis. Scand J Infect Dis. 2008;40(11-12):981-3. [Medline].

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Further Reading

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Keywords

species, endocarditis, gram-negative endocarditis

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Contributor Information and Disclosures

Author

Isaac P Humphrey, MD, Assistant Professor of Internal Medicine, Uniformed Services University of the Health Sciences; Clinical Assistant Professor of Internal Medicine, Wright State University Boonshoft School of Medicine
Isaac P Humphrey, MD is a member of the following medical societies: American College of Physicians and American Medical Association
Disclosure: Nothing to disclose.

Coauthor(s)

Mirabelle Kelly, MD, Fellow, Department of Microbiology and Infectious Disease, University of Sherbrooke, Canada
Mirabelle Kelly, MD is a member of the following medical societies: Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.

Barnett Gibbs, MD, Assistant Chief, Department of Clinical Trials, Walter Reed Army Institute of Research, Infectious Disease Service, National Capital Consortium; Assistant Professor of Medicine, Uniformed Services University of the Health Sciences
Disclosure: Nothing to disclose.

Christian P Sinave, MD, Associate Professor, Department of Medical Microbiology and Infectious Diseases, University of Sherbrooke, Canada
Christian P Sinave, MD is a member of the following medical societies: American Society for Microbiology and Canadian Infectious Disease Society
Disclosure: Nothing to disclose.

Medical Editor

Kenneth C Earhart, MD, Deputy Head, Disease Surveillance Program, United States Naval Medical Research Unit #3
Kenneth C Earhart, MD is a member of the following medical societies: American College of Physicians, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, and Undersea and Hyperbaric Medical Society
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

John L Brusch, MD, FACP, Assistant Professor of Medicine, Harvard Medical School; Consulting Staff, Department of Medicine and Infectious Disease Service, Cambridge Health Alliance
John L Brusch, MD, FACP is a member of the following medical societies: American College of Physicians and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

CME Editor

Eleftherios Mylonakis, MD, Clinical and Research Fellow, Department of Internal Medicine, Division of Infectious Diseases, Massachusetts General Hospital
Eleftherios Mylonakis, MD is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians, American Society for Microbiology, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

Chief Editor

Burke A Cunha, MD, Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital
Burke A Cunha, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, and Infectious Diseases Society of America
Disclosure: Nothing to disclose.

 
 
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