What is a common effect of antibiotic resistance in bacterial populations?

The common effect of antibiotic resistance in bacterial populations is higher treatment failures. When bacteria develop resistance to antibiotics, the medications that were previously effective in eliminating them become less useful or even ineffective. This can lead to a situation where infections are no longer manageable with the standard treatments available, resulting in treatment failures. Patients may not experience the desired improvement in their condition, leading to prolonged illness, increased medical costs, and potentially severe health complications.

In contrast, increased effectiveness of antibiotics would be contrary to the nature of antibiotic resistance, as resistant bacteria would be less susceptible to treatment. Decreased bacterial virulence does not directly relate to antibiotic resistance; in fact, some resistant strains may be just as virulent or even more so. Lastly, lower infection rates might occur due to effective public health measures or improved hygiene but are not a direct consequence of antibiotic resistance itself. Instead, antibiotic resistance often leads to more complicated treatment scenarios, increasing the incidence of treatment failures.