Measurement of antibacterial activity
Start with the big picture
The lesson moves from the historical phenol coefficient and its variants to standardized tests that examine disinfectant performance in suspension, on carriers, or in practical use. It distinguishes the Rideal–Walker method from the Chick–Martin modification, which incorporates organic matter, and introduces capacity, use-dilution, suspension, in-use, and quantitative carrier tests. Microbiological endpoints include inhibition zones, MIC, MBC, and time-kill curves. The topic also introduces quantitative measures such as D-value and the coefficient of dilution. Together, these methods help describe potency, persistence, and killing over time, while their differing conditions and limitations shape how results should be interpreted.
What you'll learn
- Explain what the phenol coefficient measures and identify its classical test variants.
- Distinguish major disinfectant tests by their setup, purpose, and measured endpoint.
- Differentiate disk diffusion, MIC, MBC, and time-kill approaches.
- Describe how D-value and coefficient of dilution relate to antibacterial activity.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
