The ATB test is performed using a plastic card that contains 15 wells. Each well contains a different antibiotic, and the concentration of the antibiotic increases from one well to the next. The bacterium to be tested is inoculated into each of the wells, and the card is incubated for a period of time. After incubation, the wells are examined for bacterial growth. If the bacterium is susceptible to an antibiotic, it will not grow in the well containing that antibiotic.
The ATB test can be used to test a wide variety of bacteria, including both Gram-positive and Gram-negative bacteria. It is a reliable and accurate method for determining antibiotic susceptibility, and it can be used to help doctors select the most effective antibiotics for treating bacterial infections.