What is the treatment for Haemophilus influenzae type b infections?

Treatment of Haemophilus influenzae Type b Infections

For Haemophilus influenzae type b infections, the recommended treatment is ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 6 hours for 10 days. 1

First-Line Antibiotic Therapy

Meningitis and Invasive Disease

• Ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 6 hours is the first-line treatment for H. influenzae type b meningitis and other invasive infections 1
• Treatment duration should be 10 days for H. influenzae infections 1
• Third-generation cephalosporins are preferred due to their excellent CSF penetration and activity against both β-lactamase-producing and non-producing strains 1
• For pediatric patients 3 months of age and older with meningitis, the recommended dose is 40 mg/kg (maximum 2 grams) every 8 hours 2

Alternative Therapy

• Moxifloxacin 400 mg once daily can be used as an alternative if cephalosporins cannot be administered 1
• Chloramphenicol (25 mg/kg every 6 hours) may be considered as an alternative in settings where cephalosporins are not available 1
• Meropenem is indicated for bacterial meningitis caused by H. influenzae in pediatric patients 3 months and older 2

Special Considerations

Antibiotic Resistance

• Due to increasing prevalence of β-lactamase-producing H. influenzae strains, ampicillin is no longer recommended as empiric therapy 3, 4
• Local antibiotic resistance patterns should be considered when selecting therapy 1
• Cephalosporins maintain excellent activity against most H. influenzae strains, including ampicillin-resistant isolates 5

Treatment Failure

• If there is no clinical improvement after 48-72 hours, consider:
  • Repeating CSF analysis to confirm sterilization 5
  • Evaluating for antibiotic resistance 1
  • Adding or switching to an alternative agent 1

Chemoprophylaxis for Contacts

• Rifampin chemoprophylaxis is recommended for:
  • Index patients treated with antibiotics other than cefotaxime or ceftriaxone (as these eradicate colonization) 1
  • All household contacts in households with members aged <4 years who are not fully vaccinated 1
  • Household contacts with immunocompromised members aged <18 years, regardless of vaccination status 1
  • Child care contacts when two or more cases of invasive Hib disease have occurred within 60 days 1
• Rifampin dosage: 20 mg/kg once daily (maximum 600 mg) for 4 days 1

Prevention

• Vaccination is the primary preventive measure against H. influenzae type b disease 1
• Previously unvaccinated household contacts under age 10 should receive Hib vaccination 1
• Antibiotic prophylaxis is recommended for preventing infection with encapsulated organisms (including H. influenzae) among allogeneic stem cell transplant recipients with chronic GVHD 1

Common Pitfalls and Caveats

• Failure to recognize β-lactamase production can lead to treatment failure with ampicillin 4
• Vancomycin should never be used alone for treatment of meningitis due to concerns about CSF penetration 1
• Cefamandole has been documented to fail in treatment of H. influenzae meningitis despite in vitro susceptibility 6
• Delay in initiating appropriate antibiotic therapy increases morbidity and mortality in invasive disease 3
• Not providing appropriate chemoprophylaxis to close contacts can result in secondary cases 1

The incidence of invasive H. influenzae type b disease has dramatically decreased since the introduction of conjugate vaccines, but appropriate antibiotic therapy remains crucial for those who do develop infection 1.