Antimicrobial resistance in Haemophilus influenzae

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Haemophilus influenzae is a significant global pathogen causing severe illness and death.
• Type b strains cause meningitis and bacteremia in unvaccinated populations.
• Nontypeable strains are linked to respiratory and ear infections.

Purpose of the Study:

• To review the diverse and widespread antibiotic resistance in Haemophilus influenzae.
• To highlight emerging resistance mechanisms affecting common antibiotics.
• To assess the current and future therapeutic options against this pathogen.

Main Methods:

• Review of intrinsic efflux resistance mechanisms.
• Analysis of beta-lactamase production prevalence and impact.
• Examination of penicillin-binding protein alterations and their resistance patterns.
• Assessment of carbapenem and quinolone susceptibility.
• Evaluation of pharmacokinetic and pharmacodynamic factors for oral agents.

Main Results:

• Intrinsic efflux limits macrolide, azalide, and ketolide activity.
• High prevalence of beta-lactamase production confers resistance to ampicillin and amoxicillin.
• Increasing penicillin-binding protein alterations (especially PBP3) drive resistance to ampicillin, amoxicillin-clavulanate, and cephalosporins.
• Carbapenems and quinolones generally maintain activity.
• Oral agent efficacy is influenced by pharmacokinetics.

Conclusions:

• Antibiotic resistance in Haemophilus influenzae is more complex than commonly perceived.
• Emerging resistance mechanisms necessitate careful antibiotic selection.
• Carbapenems and quinolones represent reliable options, but pharmacokinetic limitations exist for oral therapies.