Final answer:
Acquired resistance to drugs, particularly antibiotics, can be caused by overusing and misusing these drugs, not following through with the full treatment plan, subtherapeutic dosing, and the use of antibiotics in livestock. These practices select for resistant strains of microbes, making future infections harder to treat.
Step-by-step explanation:
Factors That Lead to Acquired Resistance:
Acquired resistance to antimicrobial drugs such as antibiotics is a significant and growing problem. This resistance can be attributed to several factors. Overuse and misuse of antimicrobials are primary contributors, where antibiotics are prescribed unnecessarily or used inappropriately. For instance, taking antibiotics for viral infections, like the common cold, is ineffective and encourages resistance. Subtherapeutic dosing and patient noncompliance with the full course of treatment also promote the survival and multiplication of resistant strains of microbes. Another contributing factor is patient noncompliance with prescribed treatments. For example if a patient with tuberculosis does not complete their lengthy course of medication which can last up to a year this can result in the evolution of multidrug-resistant or extensively drug-resistant strains of the disease.
The use of antibiotics in livestock is another important factor. In some cases, 70 percent of the antibiotics produced are utilized in animal feed, often at low doses, which maximizes the potential for the development of resistance. These resistant bacteria can then be transferred to humans. The outcomes of resistance are severe leading to infections that are difficult, and sometimes impossible to treat.