Antimicrobial susceptibility tests are used to determine which specific antibiotics a particular bacteria or fungus is sensitive to. Most often, this testing complements a Gram stain and culture, the results of which are obtained much sooner. The goal of antimicrobial susceptibility testing is to predict the in vivo success or failure of antibiotic therapy. Tests are performed in vitro , and measure the growth response of an isolated organism to a particular drug or drugs.
Select a pure culture plate of one of the organisms to be tested. Aseptically emulsify a colony from the plate in the sterile saline solution. ... Repeat until the turbidity of the saline solution visually match that of the standard turbidity. Take a sterile swab and dip it into the broth culture of organism.