[How to read new antimicrobial susceptibility testing results?]

Area of Science:

• Microbiology
• Clinical Pharmacology

Context:

• Antimicrobial susceptibility testing (AST) results have evolved.
• Previous categories ('susceptible', 'intermediate', 'resistant') are replaced.
• New categories include 'susceptible, standard dosing regimen' and 'susceptible, increased exposure'.

Purpose:

• To explain the new antimicrobial susceptibility testing (AST) result categories.
• To guide clinicians in interpreting these updated AST results.
• To clarify the roles of laboratories and clinicians in AST interpretation.

Summary:

• AST results now use 'susceptible, standard dosing regimen', 'susceptible, increased exposure', and 'resistant'.
• Laboratories now handle interpretation uncertainties previously in the 'intermediate' category.
• 'Susceptible' categories indicate high therapeutic success with appropriate dosing.

Impact:

• This shift aids clinicians in making informed treatment decisions.
• A new dosing table is available to support appropriate regimen selection.
• Enhanced understanding of AST results improves antimicrobial stewardship.