Journal of Animal Research and Nutrition

Description

Antimicrobial Resistance (AMR) is a growing global concern, with significant implications for public health, agriculture and veterinary medicine. In animal production, the use of antimicrobial agents such as antibiotics, antifungals and antiparasitics is common to prevent and treat infections, promote growth and enhance productivity. However, inappropriate or excessive use of these agents can lead to the development of resistant microorganisms, complicating the treatment of infections and posing risks to both animals and humans. This article describes the mechanisms of antimicrobial resistance in animal production, its causes, consequences and potential strategies for mitigation.

Antimicrobial resistance in animal production

AMR in animal production occurs when bacteria, fungi, viruses or parasites that cause infections in animals evolve to become resistant to the drugs that would normally kill or inhibit them. The use of antimicrobials in veterinary medicine is often need for maintaining animal health and ensuring food safety, but it can also contribute to the emergence and spread of resistant pathogens. When animals are exposed to antimicrobial agents, bacteria can acquire resistance through several mechanisms, leading to the survival of those pathogens that were previously susceptible.

Mechanisms of antimicrobial resistance

The development of antimicrobial resistance in animal production is driven by various genetic and biological processes. One of the simplest mechanisms of AMR is genetic mutation. Mutations can occur naturally in microbial populations and are a random process. These mutations can affect the target sites of antimicrobial agents, rendering them ineffective. For instance, a mutation may alter the bacterial ribosome or the structure of the cell wall, preventing antibiotics from binding and disrupting the bacterial functions. Though mutations alone are often not sufficient for full resistance, they can provide the foundation for the development of resistance when combined with other mechanisms.

These mechanisms significantly contribute to the rapid spread of resistance across bacterial populations in animal farms and can also result in the transfer of resistant strains from animals to humans. Efflux pumps are transport proteins found in bacterial cell membranes that actively pump out harmful substances, including antimicrobial agents. Some bacteria have evolved to overexpress these pumps, thereby expelling antibiotics before they can exert their effect. This mechanism allows bacteria to survive in the presence of otherwise lethal concentrations of antimicrobials. Efflux pumps can contribute to resistance against a wide range of drugs, including tetracyclines, macrolides and fluoroquinolones.

Some bacteria produce enzymes that can inactivate or modify antimicrobial agents. For example, β-lactamase enzymes break down the β-lactam ring in antibiotics like penicillin, rendering them ineffective. Extended-Spectrum Β-Lactamases (ESBLs) and carbapenemases are enzymes that confer resistance to a broader spectrum of antibiotics, including some last-resort drugs. Similarly, other bacteria may produce acetyltransferases or phosphotransferases that modify antibiotics, preventing them from binding to their targets. The consequences of AMR in animal production are far-reaching. In animals, infections caused by resistant bacteria can result in prolonged illness, increased mortality and reduced productivity. Infections that were previously easy to treat may become difficult or impossible to control, leading to economic losses for farmers and the need for more expensive treatment options. AMR also poses a serious threat to public health. Resistant bacteria can be transmitted from animals to humans through direct contact, consumption of contaminated animal products or environmental exposure. This cross-species transmission can contribute to the spread of resistance in human medicine, making infections harder to treat and increasing the burden on healthcare systems.

Antimicrobial resistance in animal production is a complex and growing challenge that requires a multifaceted approach. Understanding the mechanisms by which resistance develops and spreads is need for designing effective interventions. Reducing the overuse and misuse of antibiotics in animal husbandry, improving veterinary care and promoting sustainable farming practices will be critical in mitigating the threat of AMR. Collaborative efforts between farmers, veterinarians, regulatory authorities and researchers are necessary to combat this global health issue effectively.