Explain how each scenario listed below would affect the Kirby Bauer disc diffusion test results:i) Thicker agar used (2 marks)

i) Thicker agar used:

The thickness of the agar in a Kirby Bauer disc diffusion test can significantly affect the results. This is because the thickness of the agar can influence the diffusion of the antibiotics from the disc into the agar.

1. If the agar is too thick, the antibiotic may not diffuse properly. This could result in a smaller zone of inhibition, which could be misinterpreted as the bacteria being more resistant to the antibiotic than they actually are.

2. On the other hand, if the agar is too thin, the antibiotic may diffuse too quickly and too far, creating a larger zone of inhibition. This could be misinterpreted as the bacteria being more sensitive to the antibiotic than they actually are.

Therefore, it's crucial to use the correct agar thickness (usually around 4mm) to ensure accurate results.