Cefaclor Susceptibility Testing 

Cefaclor is a second-generation cephalosporin antibiotic with activity against a range of Gram-positive and Gram-negative bacteria. It is primarily used to treat respiratory tract infections, skin and soft tissue infections, and urinary tract infections. Susceptibility testing for cefaclor is crucial to determine its efficacy against specific pathogens, especially given the prevalence of beta-lactamase-mediated resistance among certain bacteria.

Content:

• Testing Methods:
  • Disk Diffusion (Kirby-Bauer Method):
    • Disks containing cefaclor (30 µg) are placed on agar plates inoculated with the bacterial isolate.
• • Minimum Inhibitory Concentration (MIC) Testing:
    • MIC is determined using broth microdilution or agar dilution methods.
    • The MIC is the lowest concentration of cefaclor that inhibits visible bacterial growth.
  • E-test (Gradient Diffusion):
    • A strip with a gradient of cefaclor concentrations is placed on an inoculated agar plate.
    • The MIC is determined at the point where the elliptical inhibition zone intersects the strip.

Application:

• Clinical Use:
  • Cefaclor is used for treating:
    • Respiratory tract infections: e.g., otitis media, sinusitis, pharyngitis, bronchitis.
    • Skin and soft tissue infections: e.g., cellulitis, impetigo.
    • Urinary tract infections (UTIs).
    • Community-acquired infections where resistance is not prevalent.
  • Susceptibility testing is critical in guiding cefaclor therapy, especially in regions with high resistance rates.
• Antimicrobial Stewardship:
  • Promotes appropriate cefaclor use to reduce selective pressure for resistance.
  • Encourages the use of cefaclor over broader-spectrum cephalosporins when susceptibility is confirmed.
• Epidemiological Surveillance:
  • Monitors resistance trends in beta-lactamase-producing organisms, such as Haemophilus influenzae and Klebsiella pneumoniae.
  • Provides data for regional and institutional antibiograms to guide empirical therapy.

Cefaclor susceptibility testing is an essential tool for guiding its clinical use, particularly in treating infections caused by common respiratory and urinary pathogens. Standardized methods like disk diffusion and MIC testing provide reliable results.