A 2013 CDC report identified the practice of routinely adding antibiotic compounds to animal feed as a major culprit in the rapid increase in the number of antibiotic-resistant strains. Agricultural practice in recent decades has encouraged the addition of antibiotics to animal feed to promote growth rather than to treat disease.

Speculate about the process by which feeding antibiotics to animals such as cattle might lead to an increase in the number of antibiotic-resistant strains of bacteria.

Key Concepts

Antibiotic Resistance

Antibiotic resistance occurs when bacteria evolve and develop the ability to survive exposure to antibiotics that would normally kill them or inhibit their growth. This process can happen through genetic mutations or the acquisition of resistance genes from other bacteria. The overuse of antibiotics, particularly in agriculture, accelerates this process, leading to the emergence of resistant strains that pose significant public health risks.

Selective Pressure

Selective pressure refers to environmental factors that favor certain traits in organisms, leading to evolutionary changes over time. In the context of antibiotic use in animal feed, the presence of antibiotics creates a selective pressure that favors bacteria with resistance traits. As susceptible bacteria are killed off, resistant bacteria survive and proliferate, increasing their prevalence in the population.

Horizontal Gene Transfer

Horizontal gene transfer is the process by which bacteria can exchange genetic material with one another, independent of reproduction. This mechanism allows for the rapid spread of antibiotic resistance genes among bacterial populations, especially in environments where antibiotics are used extensively, such as in livestock. This transfer can occur through various methods, including transformation, transduction, and conjugation, further complicating efforts to control antibiotic resistance.