If there is too much moisture on the surface of a Mueller-Hinton plate when performing a Kirby-Bauer susceptibility test, what will happen to the growth?

In the context of the Kirby-Bauer susceptibility test, the presence of excessive moisture on the surface of a Mueller-Hinton plate can significantly impact the results. When there is too much moisture, it creates an environment conducive to the spread of bacterial growth, which can lead to a confluent growth pattern across the agar plate.

This excessive moisture can cause the antibiotic discs to diffuse unevenly and not create distinct zones of inhibition as intended. Therefore, while a larger zone of inhibition indicates effective antibiotic action, increased moisture typically leads to reduced clarity in zone formation, which can manifest as a smaller zone of inhibition or even confluent growth.

In summary, when too much moisture is present, it negatively affects the ability of antibiotics to create clear and distinguishable zones of inhibition, which translates to smaller zones or confluent growth patterns, rather than larger, clearly defined zones.