What is meant by "selective pressure" in antibiotic use?

Selective pressure refers to the phenomenon where the use of antibiotics creates an environment that favors the survival and proliferation of bacteria that have or develop resistance to those antibiotics. When antibiotics are used, they kill susceptible bacteria, but if a few resistant bacteria are present, they can survive and multiply. This selective advantage means that over time, the population of bacteria may shift towards those that are resistant, diminishing the effectiveness of the antibiotics.

This concept is critical to understanding antimicrobial stewardship, as it emphasizes the need to use antibiotics judiciously to prevent the emergence and spread of resistance in bacterial populations. In contrast, the other options do not accurately reflect the consequences of antibiotic use. For example, the notion of increased effectiveness of antibiotics over time does not accurately describe the implications of resistance and selective pressure.