How is Antibiotic Susceptibility Testing Performed?
AST can be performed using several methods, including:
Disk Diffusion Method: Also known as the Kirby-Bauer test, this method involves placing antibiotic-impregnated paper disks on an agar plate inoculated with the bacteria being tested. Zones of inhibition are measured to determine susceptibility. Broth Dilution Method: This involves diluting antibiotics in broth and incubating them with the bacteria. The minimum inhibitory concentration (MIC) is determined by the lowest concentration of antibiotic that prevents visible growth. E-test: A gradient method that combines elements of both the disk diffusion and broth dilution methods, providing an MIC value on an agar plate. Automated Systems: These systems, such as VITEK or Phoenix, use advanced technology to quickly and accurately determine antibiotic susceptibility.
