FPGEE for National Association of Boards of Pharmacy (NABP) Practice Exam

What indicates a significant post-antibiotic effect (PAE)?

1. Bacterial growth resumes immediately after drug removal

2. Antibacterial activity persists beyond drug presence above MIC

3. Consistent MIC regardless of drug concentration

4. No effect on bacterial regrowth

The correct answer is: Antibacterial activity persists beyond drug presence above MIC

A significant post-antibiotic effect (PAE) refers to the phenomenon where antibacterial activity continues even after the antibiotic concentration has fallen below the minimum inhibitory concentration (MIC). The persistence of antibacterial activity beyond the presence of the drug is a defining characteristic of PAE, indicating that the drug has induced a lasting effect on the bacteria, which may be due to various factors such as metabolic inhibition or damage to the bacterial cell structure. Understanding why this is the correct answer is essential, as it highlights the relevance of PAE in clinical settings. It suggests that even after treatment with an antibiotic has stopped, the effect of the drug continues to hinder bacterial growth, which can be beneficial in optimizing dosing schedules and improving patient outcomes. The other options do not accurately describe the concept of PAE. For instance, if bacterial growth resumes immediately after drug removal, this indicates the absence of a significant PAE, suggesting that the drug did not exert a lasting effect. A consistent MIC regardless of drug concentration does not pertain to PAE or its implications on bacterial regrowth. Lastly, no effect on bacterial regrowth would also imply that the antibiotic did not achieve a PAE, as the lack of impact on regrowth indicates that the bacteria are unaffected after the drug is