Cefotetan Susceptibility Testing 

Cefotetan is a second-generation cephalosporin with extended activity against Gram-negative bacteria and notable anaerobic coverage due to its stability against some beta-lactamases. It is commonly used for intra-abdominal infections, gynecological infections, and surgical prophylaxis. Susceptibility testing for cefotetan is important to guide therapy, particularly in light of beta-lactamase-producing pathogens.

Content:

• Testing Methods:
  • Disk Diffusion (Kirby-Bauer Method):
    • Disks containing cefotetan (30 µg) are placed on Mueller-Hinton agar plates inoculated with the bacterial isolate.
    • After incubation, the diameter of the inhibition zone is measured and interpreted using CLSI or EUCAST guidelines.
  • Minimum Inhibitory Concentration (MIC) Testing:
    • MIC testing is performed using broth microdilution, agar dilution, or automated systems.
    • The MIC is the lowest concentration of cefotetan that inhibits visible bacterial growth.
• • Automated Systems:
    • Platforms like Vitek, Phoenix, or MicroScan may include cefotetan in their panels.

Application:

• Clinical Use:
  • Cefotetan is used for:
    • Surgical prophylaxis, particularly for colorectal and gynecologic surgeries.
    • Intra-abdominal infections, often combined with metronidazole for enhanced anaerobic coverage.
    • Gynecological infections, including pelvic inflammatory disease (PID).
    • Skin and soft tissue infections caused by susceptible organisms.
    • Urinary tract infections (UTIs) caused by susceptible Enterobacterales.
• Antimicrobial Stewardship:
  • Encourages the use of cefotetan in targeted therapy, reducing reliance on carbapenems or broader-spectrum cephalosporins.
  • Supports de-escalation of therapy based on susceptibility results.
• Epidemiological Surveillance:
  • Monitors resistance trends in Enterobacterales and anaerobic pathogens, particularly in beta-lactamase-producing strains.
  • Tracks the emergence of carbapenem-resistant organisms and their impact on cefotetan efficacy.

Cefotetan susceptibility testing is essential for managing infections caused by Gram-negative and anaerobic bacteria, particularly in the context of rising beta-lactamase production. Standardized methods, including disk diffusion and MIC testing, provide reliable results.