Phage killing experiment

Table of contents
  1. Phage killing experiment


To assess how effectively your phage kills bacteria and to compare it’s killing efficiency to other phages


If we want to use our phages for applications such as phage therapy and bioremediation, we need to be able to measure how efficienty they kill bacteria. We can compare all the phages we have in their ability to kill bacteria, and choose the best candidate for biomedical or biotechnological applications.

Phage killing experiment


  • Culture tubes
  • LB broth
  • Bacterial cultures (bacterial density of approximately 109
  • Plaque-pure phage lysates of a known concentration (PFU/ml)

Procedure for phage killing experiment

  1. Discuss among your group what a good ratio of phage to bacteria would be in this experiment and decide the ratio to use. This ratio is called the molarity of infection (MOI).
  2. Dilute your phage stock so that it is at the concentration needed for the chosen phage : cell ratio
  3. Set up two culture tubes per phage you are testing. Label both tubes with your initials. Label one tube with your phage name, and one tube “phage-free control”
  4. Add 5 µL of your bacterial cells to each of the tubes
  5. Add 5 µL of your phage (diluted to the correct concentration for the chosen phage : cell ratio) to the tube labeled with your phage.
  6. Incubate the tubes with shaking overnight.