Which testing method is used to measure how effective an antibiotic is against bacteria?

The effectiveness of an antibiotic against bacteria is assessed using antimicrobial susceptibility testing. This method involves exposing bacteria to various antibiotics and observing their growth response. In the laboratory setting, techniques such as the disk diffusion method (Kirby-Bauer test) or broth dilution techniques are commonly employed. These methods allow clinicians to determine the minimum inhibitory concentration (MIC) or the zone of inhibition, which reflects how susceptible or resistant the bacteria are to the antibiotic being tested.

Antimicrobial susceptibility testing is crucial for guiding treatment decisions, ensuring that healthcare providers can select the most effective antibiotic for a particular infection, which ultimately leads to better patient outcomes and helps mitigate the problem of antibiotic resistance.