Antibiotic Resistance and Natural Selection

Introduction

• Strep throat: Caused by bacteria; often treated with antibiotics.
• Antibiotics: Designed to destroy prokaryote cells (bacteria) and not eukaryote cells.

Natural Selection Explained

• Example with frogs:
  • Habitat: Frogs have a variety of traits.
  • Predators: Easier to see lighter-colored frogs.
  • Fitness: Darker frogs survive and reproduce more, passing their DNA.
  • Outcome: Over time, more darker frogs; possible complete population change to darker frogs due to natural selection.
  • Alleles: Recessive alleles can persist in the population; variation is due to random mutations and crossing over.
  • Random variation: Essential for natural selection, not a result of organisms' will.

Application to Bacteria

• Antibiotic resistance: Similar to the frog example, bacteria with traits for antibiotic resistance survive and reproduce.
• Random mutations: Lead to variations such as enhanced cell walls or enzyme production.
• Environment alteration: Antibiotics kill non-resistant bacteria, allowing resistant bacteria to thrive.
• Gene transfer: Bacteria can share resistance genes, spreading resistance.
• Clinical implications: Resistance increases difficulty in treating infections; important for healthcare hygiene to prevent spread.

Addressing Antibiotic Resistance

• New antibiotics: Development is ongoing to stay ahead of resistance.
• Prudent use: Only take antibiotics for bacterial infections, not viral to avoid unnecessary resistance selection.
• Vaccination: Protects against serious bacterial infections (e.g., DTaP vaccine).

Conclusion

• Natural selection shows observable evolution in bacteria within a shorter time frame.
• Importance of careful antibiotic use and maintaining good hygiene practices in healthcare.

Stay curious!