The emergence of resistance of bacteria to antibiotics is a common phenomenon. Emergence of resistance often reflects evolutionary processes that take place during antibiotic therapy. The antibiotic treatment may select for bacterial strains with physiologically or genetically enhanced capacity to survive high doses of antibiotics. Under certain conditions, it may result in preferential growth of resistant bacteria, while growth of susceptible bacteria is inhibited by the drug. For example, antibacterial selection for strains having previously acquired antibacterial-resistance genes was demonstrated in 1943 by the Luria–Delbrück experiment. Antibiotics such as penicillin and erythromycin, which used to have a high efficacy against many bacterial species and strains, have become less effective, due to the increased resistance of many bacterial strains. COUNT 8
QSN1 What is a modern common occurence with antibiotics? ANS1 resistance of bacteria QSN2 What is resistance to antibiotics a cause of? ANS2 evolution QSN3 When was the Luria-Delbruck experiment? ANS3 1943 QSN4 Which two antibiotics that have high efficacy are much less useful now? ANS4 penicillin and erythromycin QSN5 What does emergence of resistance reflect? ANS5 evolutionary processes QSN6 What is the purpose of antibiotic treatment? ANS6 survive high doses of antibiotics QSN7 When was antibacterial-resistance demonstrated? ANS7 1943 QSN8 Who made the demonstration in 1943? ANS8 Luria–Delbrück