eMedicine Specialties > Infectious Diseases > Bacterial Infections
HACEK Group Infections: Treatment & Medication
Updated: Nov 6, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
Medical Care
- Appropriate antibiotic therapy is central to the management of infective endocarditis (IE) caused by the HACEK organisms (see Medications).
- Diagnosis should be clearly established before starting treatment because administration of antimicrobial agents to patients with IE before blood cultures are obtained reduces the recovery rate of bacteria by 35%-40%.
- Older literature suggested that standard beta-lactam antibiotics were the drugs of choice for HACEK infections. However, recent data suggest that beta-lactam resistance is prevalent and that broader-spectrum agents are needed for initial therapy. Based on Infectious Diseases Society of America (IDSA)–endorsed guidelines, ceftriaxone and ampicillin-sulbactam are excellent initial choices.7
- In the case of beta-lactam allergy, a fluoroquinolone (eg, ciprofloxacin, levofloxacin, moxifloxacin) may be used. The clinical data on the use of fluoroquinolones in this setting are limited, so they should be reserved for patients who cannot tolerate the standard regimen.7
- Antibiotic therapy may be fine tuned when susceptibility data for the causative organism are available.
- Complications that arise (eg, heart failure, embolic complications) also require supportive medical therapy.
Surgical Care
- The decision to consider surgical therapy in patients with IE is often challenging and must be made on an individual basis. Below are several accepted indications for surgery in IE.7
- 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.
- 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
Consultations
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.
Diet
No special diet is necessary in patients with HACEK group infections.
Activity
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.
Medication
Traditionally, treatment for infection with HACEK organisms had been with penicillin or ampicillin alone or in combination with an aminoglycoside. However, resistance due to beta-lactamase has been reported throughout the HACEK group. For the allergic patient or if the organism shows resistance, many other options are available. The decision of which drug to use should be based on susceptibility data, when available.
Empiric therapy with ceftriaxone or ampicillin-sulbactam is the recommended approach. Fluoroquinolones can be used in the case of allergy or intolerance to the recommended regimen. Treatment duration is 4 weeks for native valve disease and 6 weeks for prosthetic valve disease.
Antibiotics
Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting.
Ceftriaxone (Rocephin)
Drug of choice for treatment of endocarditis due to HACEK organisms. Third-generation cephalosporin with broad-spectrum, gram-negative activity. Lower efficacy against gram-positive organisms and higher efficacy against resistant organisms. Arrests bacterial growth by binding to one or more penicillin-binding proteins. No adjustment necessary in persons with renal or hepatic impairment. Dose should be administered postdialysis if undergoing hemodialysis.
Adult
2 g IV q24h
Pediatric
100 mg/kg IV q24h
Probenecid may increase levels; coadministration with ethacrynic acid, furosemide, and aminoglycosides may increase nephrotoxicity
Documented hypersensitivity; hyperbilirubinemic neonates, particularly those who are premature (reported to displace bilirubin from albumin-binding sites)
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Caution in breastfeeding women and allergy to penicillin; may cause antibiotic-associated colitis or colitis secondary to Clostridium difficile; adverse reactions include rash, diarrhea, eosinophilia, thrombocytosis, leukopenia, elevated transaminases, increased BUN, and local pain and induration at injection site; pseudobiliary lithiasis may require cholecystectomy
Ampicillin and sulbactam (Unasyn)
Drug combination of beta-lactamase inhibitor with ampicillin. Interferes with bacterial cell wall synthesis during active replication, causing bactericidal activity against susceptible organisms. Alternative to amoxicillin when unable to take medication orally.
Covers skin, enteric flora, and anaerobes. Not ideal for nosocomial pathogens.
Adult
3 g (2 g ampicillin + 1 g sulbactam) IV q 6h
Pediatric
<3 months: Not established
3 months to 12 years: 300 mg ampicillin/kg/d IV divided q6h
>12-years: Administer as in adults; not to exceed 4 g/d sulbactam or 8 g/d ampicillin
Probenecid and disulfiram elevate ampicillin levels; allopurinol decreases ampicillin effects and has additive effects on ampicillin rash; may decrease effects of oral contraceptives
Documented hypersensitivity
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Adjust dose in renal failure; evaluate rash and differentiate from hypersensitivity reaction
Ciprofloxacin (Cipro)
Alternative to ceftriaxone. Fluoroquinolone with activity against some pseudomonads, streptococci, MRSA, Staphylococcus epidermidis, and most gram-negative organisms, but no activity against anaerobes. Inhibits bacterial DNA synthesis and, consequently, growth.
Adult
500 mg PO q12h or 400 mg IV q12h
Pediatric
Not recommended
Antacids, iron salts, and zinc salts may reduce serum levels; administer antacids 2-4 h before or after taking fluoroquinolones; cimetidine may interfere with metabolism of fluoroquinolones; reduces therapeutic effects of phenytoin; probenecid may increase serum concentrations; may increase toxicity of theophylline, caffeine, cyclosporine, and digoxin (monitor digoxin levels); may increase effects of anticoagulants (monitor PT); enteral feedings may decrease plasma concentrations (probably by >30%); nasogastric administration produces greater loss in activity than nasoduodenal administration; discontinued feeding for 1-2 h prior to and after administration; didanosine and sucralfate may decrease effects by approximately 90% if administered concurrently with ciprofloxacin
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
In prolonged therapy, perform periodic evaluations of organ system functions (eg, renal, hepatic, hematopoietic); adjust dose in renal function impairment; superinfections may occur with prolonged or repeated antibiotic therapy; has caused arthropathy in children; green discoloration of teeth has been reported in newborns; rarely causes inflamed and ruptured tendons; CNS stimulation may occur; may cause seizures; avoid in patients with renal insufficiency or CNS disorders
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
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Further Reading
Keywords
species, endocarditis, gram-negative endocarditis
