Agar disk diffusion for the quality control testing of Autobac elution disks

Area of Science:

• Clinical Microbiology
• Pharmaceutical Science

Background:

• The disk diffusion method is a standard technique for antimicrobial susceptibility testing.
• Monitoring the potency and reproducibility of antibiotic elution disks is crucial for accurate clinical laboratory diagnostics.

Purpose of the Study:

• To evaluate the stability and reproducibility of Autobac antibiotic elution disks over an eight-month period.
• To assess the performance of Autobac disks using the standard disk diffusion method.

Main Methods:

• The standard disk diffusion method, as described by Bauer et al. and NCCLS, was employed.
• Sixteen Autobac antibiotic elution disks were tested.
• Three recommended Autobac control strains were utilized for monitoring.

Main Results:

• Excellent reproducibility was observed in the zone sizes obtained.
• All zone sizes fell within a narrow 5-mm range.
• Standard deviations for zone sizes ranged from 0.6 to 1.3 mm, indicating high consistency.

Conclusions:

• Autobac antibiotic elution disks exhibit stable potency and reliable performance over an eight-month period.
• The standard disk diffusion method provides reproducible results when used with Autobac control strains.
• These findings support the continued use of Autobac disks in clinical settings for accurate antimicrobial susceptibility testing.