The Continued Value of Disk Diffusion for Assessing Antimicrobial Susceptibility in Clinical Laboratories: Report...

Area of Science:

• Clinical Microbiology
• Antimicrobial Resistance
• Diagnostic Device Development

Background:

• Expedited antimicrobial drug approval by the U.S. Food and Drug Administration (FDA) creates delays in the availability of cleared antimicrobial susceptibility testing (AST) devices.
• Antimicrobial disks for disk diffusion testing are often among the first AST devices available, yet face implementation barriers in clinical laboratories.
• Laboratory reluctance stems from decreased proficiency, workflow disruption, quality concerns, and a perceived need for Minimum Inhibitory Concentration (MIC) values.

Purpose of the Study:

• To report on current standards for disk diffusion testing.
• To assess the clinical utility of disk diffusion testing in the context of delayed AST device availability.
• To address laboratory concerns regarding the implementation and reliability of disk diffusion methods.

Main Methods:

• This minireview synthesizes information from the Clinical and Laboratory Standards Institute (CLSI) Methods Development and Standardization Working Group.
• It focuses on existing standards and clinical data related to disk diffusion testing.
• The review addresses common laboratory challenges and perceptions of the method.

Main Results:

• Disk diffusion testing remains a relevant and accessible method for AST, often available before other device types.
• Despite challenges, established standards provide a framework for reliable disk diffusion testing.
• The review acknowledges but also implicitly counters concerns regarding proficiency and workflow by focusing on standards and utility.

Conclusions:

• Disk diffusion testing, supported by CLSI standards, offers a valuable and timely approach to AST.
• Addressing laboratory concerns and emphasizing adherence to standards can enhance the implementation and reliability of this method.
• Disk diffusion testing plays a crucial role in guiding antimicrobial therapy, especially when newer AST devices are delayed.