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Molecular basis of the efficacy of cefaclor against Haemophilus influenzae

M Picard1, F Malouin

  • 1Département de Microbiologie and Laboratorie, Centre Hospitalier de l'Université Laval, Québec, Canada.

Antimicrobial Agents and Chemotherapy
|November 1, 1992
PubMed

Insights

Cefaclor effectively inhibits beta-lactamase-producing Haemophilus influenzae. Its superior resistance to beta-lactamase enzymes allows for higher concentrations in the periplasmic space, enhancing its antibacterial activity.

Area of Science:

  • Microbiology
  • Pharmacology
  • Infectious Diseases

Background:

  • Beta-lactamase-producing bacteria, such as Haemophilus influenzae, pose a significant challenge in treating infections.
  • Understanding the mechanisms of antibiotic efficacy against resistant strains is crucial for effective treatment strategies.

Purpose of the Study:

  • To investigate the inhibitory activity and mechanism of cefaclor against a beta-lactamase-producing strain of Haemophilus influenzae.
  • To compare the efficacy of cefaclor with ampicillin in this resistant bacterial strain.

Main Methods:

  • Assessing the inhibitory activity of cefaclor against Haemophilus influenzae.
  • Calculating permeability coefficients for cefaclor and ampicillin.
  • Measuring periplasmic concentrations of both antibiotics.

Main Results:

  • Cefaclor demonstrated sustained inhibitory activity against the beta-lactamase-producing Haemophilus influenzae.
  • Despite ampicillin having a higher calculated permeability coefficient, cefaclor achieved a 5.7-fold higher periplasmic concentration.
  • Cefaclor exhibited greater resistance to beta-lactamase activity.

Conclusions:

  • Cefaclor's enhanced efficacy against beta-lactamase-producing Haemophilus influenzae is attributed to its superior beta-lactamase resistance.
  • Higher periplasmic concentrations of cefaclor facilitate adequate binding to essential penicillin-binding proteins, leading to effective bacterial inhibition.

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