What is the recommended treatment for Elizabethkingia (E. kingae) infections?

Treatment of Elizabethkingia (E. kingae) Infections

For Elizabethkingia infections, the recommended treatment is fluoroquinolones (ciprofloxacin or levofloxacin), which have demonstrated superior efficacy compared to other antimicrobial options.

Understanding Elizabethkingia

• Elizabethkingia species are non-fermentative Gram-negative bacilli that have emerged as important pathogens in nosocomial infections 1
• These organisms are inherently resistant to many broad-spectrum antibiotics, making appropriate antibiotic selection crucial for survival 1
• Common species include E. anophelis (most prevalent), E. meningoseptica, and E. miricola 2

First-line Treatment Options

• Fluoroquinolones are the preferred treatment for Elizabethkingia infections:
  • Ciprofloxacin (400 mg IV every 8-12 hours or 750 mg orally every 12 hours) 3, 1
  • Levofloxacin (typically 750 mg daily) 1
  • Fluoroquinolone treatment has demonstrated significantly lower 14-day mortality compared to non-fluoroquinolone treatment (8.3% vs 33.3%) 1

Alternative Treatment Options

• Trimethoprim/sulfamethoxazole has shown activity against >90% of Elizabethkingia isolates 2
• Tetracyclines (doxycycline, minocycline) inhibit >90% of Elizabethkingia species 2
• Rifampin has activity against certain species (100% of E. meningoseptica and 81.1% of E. anophelis) 2
• Vancomycin combined with other agents may be considered for certain infections, particularly meningitis 4, 5

Treatment Considerations for Specific Infections

For Bloodstream Infections:

• Fluoroquinolone therapy (ciprofloxacin or levofloxacin) is the preferred treatment 1
• Alternative options include trimethoprim/sulfamethoxazole or piperacillin/tazobactam if susceptible 1

For Meningitis:

• Combination therapy is often required due to high resistance patterns 4
• Successful treatment has been reported with regimens including:
  • Vancomycin plus ciprofloxacin 4, 5
  • Vancomycin, rifampin, ciprofloxacin, and trimethoprim/sulfamethoxazole in combination for resistant strains 4

Duration of Therapy

• For serious infections like bacteremia or meningitis, treatment duration of at least 3-6 weeks is recommended 4, 5
• For endocarditis or other invasive infections, treatment should be extended to at least 6 weeks 3

Important Considerations

• Susceptibility testing is essential due to the multidrug-resistant nature of Elizabethkingia species 2
• There may be discrepancies between different susceptibility testing methods (broth microdilution vs. automated systems) 2
• Consultation with an infectious disease specialist is strongly recommended due to the complex resistance patterns 3
• Most isolates are resistant to nearly all tested β-lactams, including newer combinations like imipenem/relebactam, meropenem/vaborbactam, and ceftazidime/avibactam 2

Monitoring and Follow-up

• Close monitoring of clinical response is essential 6
• Repeat cultures should be obtained to confirm clearance of infection 4
• For central nervous system infections, follow-up imaging and CSF analysis may be necessary 4

Pitfalls and Caveats

• Ceftriaxone, a commonly used drug for intracranial infections, is typically ineffective against Elizabethkingia species 7
• Automated susceptibility testing systems (like VITEK 2) may have significant discrepancy rates for certain antibiotics including ciprofloxacin, moxifloxacin, vancomycin, and trimethoprim/sulfamethoxazole 2
• Elizabethkingia infections are associated with high mortality rates if not treated appropriately 1