This document discusses antimicrobial susceptibility testing, which determines how well a microbe will respond to different antibiotic drugs. There are two main methods: disk diffusion testing, which uses disks containing antibiotics placed on an agar plate, and minimum inhibitory concentration (MIC) testing, which finds the lowest concentration of antibiotics that prevents microbial growth. The results of these tests guide the selection of effective antibiotic treatment based on whether a microbe is susceptible, resistant, or intermediately resistant to various drugs.