The Kirby-Bauer disk diffusion test is a laboratory method used to determine the susceptibility of bacteria to antibiotics. In this test, a bacterial culture is spread evenly on an agar plate, and small paper disks containing specific antibiotics are placed on the surface. After incubation, the plates are examined for clear zones around the disks, indicating where the bacteria could not grow due to the antibiotic's effect. The size of these clear zones, known as inhibition zones, helps determine whether the bacteria are sensitive, intermediate, or resistant to the antibiotics tested. This information is crucial for guiding effective treatment options for infections caused by the bacteria, ensuring that the right antibiotics are used to combat the infection.