Question

What is the role of “Persister cells” in emergence of antibiotic resistance in Gram Positive bacteria?

Hint:

Persister cells are not genetically resistant but rather are dormant, making them difficult to kill with antibiotics.

Answer 1

Step 1: Understanding Persister cells.
Persister cells are a subpopulation of bacterial cells that are metabolically dormant and highly tolerant to antibiotics. Unlike resistant bacteria, persister cells do not have genetic mutations that confer resistance, but instead enter a dormant state that allows them to survive antibiotic treatment. These cells can survive even in the presence of high concentrations of antibiotics.

Step 2: Role of Persister cells in resistance.
- In Gram-positive bacteria, persister cells contribute to the persistence of infection despite antibiotic treatment. - They form a small, dormant fraction of the bacterial population and can "hibernate" under stressful conditions, such as exposure to antibiotics. - Once the antibiotic treatment is stopped or the environment becomes more favorable, these persister cells can "wake up" and begin to multiply, potentially leading to the recurrence of the infection. - Importantly, persister cells can act as a reservoir for the regrowth of resistant strains, as they often survive in areas with limited antibiotic penetration, such as in biofilms.

Step 3: Mechanism of persistence.
Persister cells do not grow or divide during antibiotic treatment, which allows them to avoid the effects of antibiotics that target dividing cells. The mechanism behind their dormancy is complex, involving changes in gene expression that reduce metabolic activity and prevent the antibiotics from having their usual effect.

Step 4: Conclusion.
The role of persister cells in Gram-positive bacteria is crucial for understanding chronic infections and the difficulty in eradicating these infections with antibiotics. These cells contribute to the recurrence of infections, as they survive antibiotic exposure and repopulate the bacterial population once the treatment ends.