What is the primary purpose of the Kirby-Bauer test?

The Kirby-Bauer test is a widely used method for determining the sensitivity or resistance of bacteria to specific antibiotics. Its primary purpose is to assess drug resistance in bacteria, providing critical information on which antibiotics are effective for treating infections caused by a particular bacterial strain. In the test, bacterial isolates are spread on an agar plate, and antibiotic-impregnated discs are placed on the surface. The bacteria grow around these discs, creating clear zones of inhibition where the drug prevents growth. The size of these zones indicates the susceptibility or resistance of the bacteria to the antibiotics tested.

Diagnosing viral infections, evaluating immune response, or confirming bacterial presence does not capture the essence of the Kirby-Bauer test. While understanding bacterial presence is important in microbiology, the Kirby-Bauer test directly focuses on how well an antibiotic can combat the bacteria, making its main objective the assessment of drug resistance.