Amoxicillin-Clavulanic Susceptibility Testing 

Amoxicillin-clavulanic acid (commonly referred to as Augmentin) is a combination antibiotic consisting of amoxicillin, a beta-lactam antibiotic, and clavulanic acid, a beta-lactamase inhibitor. This combination enhances the spectrum of amoxicillin by overcoming beta-lactamase-producing bacteria, which are resistant to beta-lactam antibiotics.

Susceptibility testing is critical for determining the effectiveness of this antibiotic combination against specific bacterial pathogens. It is performed in clinical microbiology laboratories to guide appropriate antimicrobial therapy for infections.

Content:

• Testing Methods:
  • Disk Diffusion (Kirby-Bauer Method):
    • A disk containing amoxicillin-clavulanate is placed on an agar plate inoculated with the test organism.
• • Minimum Inhibitory Concentration (MIC) Testing:
    • MIC is determined using broth microdilution or automated systems (e.g., Vitek, Phoenix).
    • The lowest concentration of amoxicillin-clavulanate that inhibits bacterial growth is recorded.
  • E-test (Gradient Diffusion):
    • A strip with a gradient of amoxicillin-clavulanate concentrations is placed on an inoculated agar plate.

Application:

• Clinical Diagnosis:
  • Used in treating respiratory tract infections, urinary tract infections (UTIs), skin and soft tissue infections, and intra-abdominal infections.
• Antimicrobial Stewardship:
  • Prevents inappropriate use of broader-spectrum antibiotics, reducing the risk of antimicrobial resistance.
• Epidemiological Surveillance:
  • Tracks resistance patterns in bacterial populations.
  • Assists in identifying emerging resistance mechanisms.
• Research and Development:
  • Used in studies on antibiotic efficacy against novel resistance mechanisms.

Amoxicillin-clavulanic susceptibility testing is a vital tool in microbiology for managing bacterial infections effectively. It employs standardized methods to determine whether this antibiotic combination will be effective against specific pathogens.