Quality control of antimicrobial disc susceptibility testing with a rapid method compared to the standard methods

Area of Science:

• Clinical Microbiology
• Pharmaceutical Science

Background:

• Accurate antimicrobial susceptibility testing is crucial for effective patient treatment.
• Standard methods for quality control of antimicrobial discs can be time-consuming.
• Ensuring the potency of antimicrobial discs used in clinical laboratories is essential.

Purpose of the Study:

• To adapt a rapid serum assay method for assessing antimicrobial disc activity.
• To develop a faster quality control method for antimicrobial discs used in susceptibility testing.
• To enable early identification and discarding of potentially ineffective antimicrobial discs.

Main Methods:

• Modified a rapid assay for antimicrobial agents in human serum.
• Applied antimicrobial discs directly to pre-inoculated, refrigerated test plates.
• Measured zones of inhibition within 5-6 hours.
• Discarded discs if inhibition zones were more than 2 standard deviations below the mean.

Main Results:

• Developed a rapid quality control method for antimicrobial discs.
• Enabled assessment of disc potency before daily susceptibility testing.
• Identified and discarded discs of questionable potency proactively.
• Achieved results with slightly smaller and more variable zones compared to standard methods.

Conclusions:

• The rapid control test offers significant advantages in speed and simplicity for quality control of antimicrobial discs.
• This method allows for the timely removal of suboptimal discs, improving the reliability of susceptibility testing.
• The trade-off of slightly decreased precision is outweighed by the practical benefits of rapid assessment.