Antibiotic Susceptibility Testing

Time for a short #IDtweetorial on Abx Susc Testing

Four major methods:

  1. Kirby Bauer Disk Diffusion: disks impregnanted w/ Abx ➡️circular gradient➡️zone of inhibition. ❌MIC
  2. Broth microdilution: Abx in 2-fold dilutions in 96-well plate. ✔️MIC

3. Gradient diffusion (E test): Hybrid between disk diffusion & broth microdilution. Strip sprayed w/abx gradient ➡️ ellipse meets strip ✔️MIC
4. Automated testing. May use abx dilutions or few abx concentrations + algorithms➡️ standardized breakpoints to determine✔️MIC

Can find each of the images in these links:

Kirby Bauer Disk diffusion example by @richdavisphd
https://twitter.com/richdavisphd/status/971513769779019776?s=20

Broth microdilution example by @1797Angel
https://twitter.com/1797Angel/status/894665762920681473?s=20

Automated susceptibility testing example by @richdavisphd

Originally tweeted by Infectious Diseases Fellows Network (@ID_fellows) on 12 August, 2020.

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