Which method serves as the international reference (gold standard) against which commercial antimicrobial susceptibility systems are calibrated and validated?

• A Kirby-Bauer disk diffusion
• B Gradient diffusion strips
• C Automated broth microdilution panels
• D Agar dilution ✓

Explanation

Agar dilution, in which defined antibiotic concentrations are incorporated into Mueller-Hinton agar and a standardized inoculum is applied with a replicator, is the CLSI and EUCAST reference method for MIC determination. Disk diffusion provides only categorical results rather than MIC values, automated panels are themselves calibrated against agar dilution, and gradient strip methods approximate but do not constitute the reference standard. Broth microdilution is the accepted routine quantitative method but agar dilution remains the benchmark.

Reference: Koneman's Color Atlas and Textbook of Diagnostic Microbiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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