HACEK Group Infections Treatment & Management

Updated: Jun 17, 2016
  • Author: Zartash Zafar Khan, MD, FACP; Chief Editor: Burke A Cunha, MD  more...
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Medical Care

Appropriate antibiotic therapy is key to the management of infective endocarditis (IE) caused by the HACEK organisms (see Medications). The Infectious Disease Society of America (IDSA) recommends the following: [28]

  • Unless in vitro growth is adequate to obtain susceptibility testing results, HACEK microorganisms are considered ampicillin-resistant, and penicillin and ampicillin should not be used for the treatment of IE. Ampicillin sodium may be an option if the growth of the isolate is sufficient to permit in vitro susceptibility results.
  • Ceftriaxone is reasonable for treatment of HACEK IE.
  • Four weeks of therapy for HACEK native-valve endocarditis is reasonable; for HACEK prosthetic valve endocarditis, a therapy duration of 6 weeks is reasonable.
  • Gentamicin is not recommended because of its nephrotoxicity risks.
  • A fluoroquinolone (ciprofloxacin, levofloxacin, or moxifloxacin) may be considered an alternative agent in patients who are unable to tolerate ceftriaxone (or other third- or fourth-generation cephalosporins).
  • Patients with HACEK IE who cannot tolerate ceftriaxone therapy should be treated in consultation with an infectious diseases specialist.

Antibiotic therapy may be fine-tuned when susceptibility data for the causative organism are available. [29]

Complications that arise (eg, heart failure, embolic complications) also require supportive medical therapy.

When treating a clenched fist injury or bite wound infection, HACEK organisms should be kept in consideration. E corrodens is resistant to macrolides, clindamycin, and metronidazole. H aphrophilus is also typically resistant to clindamycin.


Surgical Care

The decision to consider surgical therapy in patients with IE is often challenging and must be made on an individual basis. The following are several accepted indications for surgery in IE: [11]

  • Refractory CHF
  • One or more embolic episode
  • Uncontrolled infection (persistently positive blood cultures after 1 week of therapy)
  • Physiologically significant valve dysfunction as demonstrated by echocardiography: According to the American Heart Association Committee on IE, criteria associated with an increased need for surgical intervention include (1) persistent vegetations after a major systemic embolic episode; (2) anterior mitral valve vegetations larger than 1 cm in diameter; (3) increase in size of vegetations after 1 month of therapy; (4) periannular extension of infection; and (5) valvular dysfunction, perforation, or rupture. [30]
  • Ineffective antimicrobial therapy (usually not the case with HACEK organisms)
  • Resection of mycotic aneurysms
  • Most cases of prosthetic valve endocarditis caused by more resistant organisms (eg, methicillin-resistant S aureus [MRSA], vancomycin-resistant enterococci [VRE], enteric gram-negative bacilli)
  • Local suppurative complications including perivalvular or myocardial abscess


Treatment of HACEK endocarditis requires a multidisciplinary approach.

Consultation with an infectious disease specialist may be helpful for selecting antibiotics, monitoring therapy, and selecting the duration of therapy.

Consultation with a cardiologist may be helpful, especially if transesophageal echocardiography is needed or if CHF develops.

Management of large vegetations or mechanical complications warrants a cardiovascular surgeon's advice.

Consultation with a dentist is indicated if periodontal disease is present.



No special diet is necessary in patients with HACEK group infections.



Although there is no evidence-based recommendation for activity levels in patients with endocarditis, it is prudent to keep activity light in the initial phase of treatment.