6 thoughts on “P58 – Long

  1. You mention the benefits of phage therapy compared to traditional antibiotics, however what are some of the drawbacks of using this therapy compared to antibitoics?

    1. Experimentation to find a specific phage that can kill a certain bacteria can take a long time if scientists have not already identified one. Phage therapy is currently only approved for clinical trials and requires conditional approval by the FDA in special cases where other treatments proved to be unsuccessful on a person. In addition, phages can trigger negative immune responses in people, even though phages specifically attack bacteria, because they are viruses foreign to the body.

  2. What is a titer indicate is that the same as concentration? Additionally what is the importance of determining this and the morphology in an applied context?

    1. Yes, a titer is essentially the concentration of viable phages that can kill/lyse bacteria. The number of active phage particles are measured in plaque-forming units per mL.

      Plaque morphology describes the characteristics of the plaque and can indicate the life cycle of the phage. Clear, well-defined plaques indicate that the bacteria was completely lysed which is specific to the lytic life cycle. Temperate phages have a cloudy halo around the rim of the plaque (which shows the bacteria was only partially lysed) due to factors such as repressor proteins that occur during the lysogenic life cycle and prevent the complete lysis of the bacterial cell. Based on current research, lytic phages are being prioritized in phage therapy because of their ability to completely lyse bacteria.

      Finally, a high titer is preferred no matter the plaque morphology or life cycle of the phage because we want a high amount of active phage particles, as opposed to inactive particles that are incapable of interacting with the bacteria.

  3. You noted that your phage completely lysed all host bacteria. What does that mean in the context of phage therapy?

    1. If you have a temperate phage, it can undergo the lysogenic lifecycle where the phage DNA integrates with the host bacteria DNA. This integration can give the bacterial cell immunity from other temperate phages. The goal of phage therapy is to use the phage virus to completely lyse/kill the bacteria and cure a patient. This is why research has focused on using lytic phages that can only undergo the lytic lifecycle and effectively kill the bacteria with less of a potential for the bacteria to develop a resistance to that phage.

Leave a Reply