In this blog post, we will examine the changes antibiotics have brought to the treatment of infectious diseases in humans, as well as the problems that antibiotic use in agriculture and livestock can cause—such as antibiotic-resistant bacteria and risks to humans, animals, and the environment—and consider South Korea’s current regulatory framework and future challenges.
Throughout history, humanity has suffered from infectious diseases caused by bacteria, both large and small. From village-level epidemics—recorded in ancient texts as “plagues”—to the Black Death that struck all of Europe in the mid-14th century and claimed the lives of a significant portion of the European population at the time, it is clear that humans have long been highly vulnerable to bacterial infections. However, this situation changed dramatically in 1928 when Alexander Fleming discovered the antibacterial properties of penicillin, which was subsequently developed into an actual medication. Antibiotics are substances that inhibit the growth of or kill microorganisms, including bacteria, and by utilizing them as medicines, humanity has been able to treat a significant portion of bacterial infections that were previously difficult to cure. In particular, as penicillin came into widespread use in medical practice starting in the 1940s, the possibilities for treating bacterial infectious diseases expanded significantly.
However, the promising future envisioned by antibiotics did not last long. Shortly after antibiotics began to be widely used, antibiotic-resistant bacteria rapidly emerged; in the United Kingdom, methicillin-resistant Staphylococcus aureus (MRSA) was first reported in 1960. Furthermore, vancomycin-resistant Staphylococcus aureus (VRSA) was first reported in the United States in 2002, not in Japan in 1996 as stated in the original text. As such, antibiotic-resistant bacteria—so-called “superbugs”—are bacteria that have acquired resistance to one or more antibiotics due to factors such as inappropriate or excessive antibiotic use and selective pressure; some bacteria even exhibit resistance to multiple types of antibiotics simultaneously. Today, antibiotic resistance has become a global public health threat, rather than merely a problem confined to specific countries or regions. According to the World Health Organization (WHO), it is estimated that approximately 1.27 million people died directly from bacterial antibiotic resistance in 2019, while the total number of deaths related to antibiotic resistance reached approximately 4.95 million. In the past, projections widely cited warned that if antibiotic resistance were not properly managed, more than 10 million people could die annually by 2050. However, the international community is now moving beyond simply predicting the number of deaths in a specific year and is focusing on managing both antibiotic usage and the spread of resistance through the “One Health” approach, which views humans, animals, and the environment as a single system. At the 2024 UN High-Level Meeting, goals were set to significantly reduce the amount of antimicrobials used in the agri-food system by 2030 and to strengthen infection prevention and the appropriate and responsible use of antimicrobials.
The primary uses of antibiotics can be broadly categorized into hospitals and the agriculture and livestock sectors. In hospitals, antibiotics are used to treat bacterial diseases, while in the agriculture and livestock sectors, they are administered to livestock to treat diseases or to control and prevent the spread of specific infections. In the past, the practice of continuously mixing antibiotics into feed and water for the purpose of promoting livestock growth or preventing disease was common in many countries. While this use of antibiotics played a certain role in reducing disease-related losses in intensive livestock farming environments, the excessive use of antibiotics increases the likelihood that antibiotic-resistant bacteria will be selected and spread. Consequently, international organizations today recommend phasing out the use of antimicrobials for the purpose of promoting growth in healthy livestock and limiting their use to veterinary purposes—namely, treatment, control, and prevention—in a responsible and prudent manner.
First, when comparing with other countries, it is necessary to examine why the quantity and methods of antibiotic use in agriculture and livestock farming are important. Data from Johns Hopkins University School of Medicine cited in the original text indicates that, in 2009, antibiotics sold for food-producing animals accounted for approximately 80% of all antibiotics sold in the United States. However, this figure does not represent global antibiotic use in the agricultural and livestock sectors; rather, it is historical data based on U.S. sales in 2009. Additionally, there is a limitation in that it is difficult to make a direct comparison between antibiotics used in humans and animals in terms of drug type, dosage, and target population. Nevertheless, the data is significant in that it demonstrates that antibiotics were being used on a substantial scale in the production of food animals at that time. Furthermore, the original text presents data indicating that, in the past, the antibiotic usage per metric ton of livestock products in South Korea’s livestock industry was higher than in Denmark and the United States. However, such cross-national comparisons can yield varying results depending on the year of the survey, the livestock species examined, the types of antibiotics, and the methods used to calculate dosages; therefore, these figures should not be taken as an accurate representation of the current situation in South Korea. What is important is not the historical figures of a specific country per se, but how antibiotics are being used in agriculture and livestock farming, and whether their usage and resistance rates are being continuously monitored.
As such, excessive use of antibiotics in livestock can lead to the selection of antibiotic-resistant bacteria in the animals’ intestines or bodies. If such resistant bacteria are present in livestock and the livestock environment, they have the potential to contaminate food during slaughter, processing, and distribution; furthermore, if proper hygiene management and thorough cooking are not practiced, they can be transmitted to humans. Of course, proper heating and hygienic processing of food play a crucial role in reducing bacterial infections transmitted through food. However, these measures alone cannot solve the entire problem of antibiotic resistance. This is because antibiotic-resistant bacteria and resistance genes can be transmitted not only through food but also through direct contact between animals and humans, the environment surrounding farms, livestock manure, soil, and water. Therefore, the high rate of antibiotic resistance found in livestock products does not simply mean that consuming such food will lead to infection by superbugs; rather, it highlights the need to manage the pathways through which antibiotic resistance spreads—linking farms, food, and the environment.
Of course, since the direct transmission of superbugs to humans through food can be largely prevented by heating and hygienic processing, those who wish to maintain the use of antibiotics in animal feed might argue that the use of antibiotics in livestock is not necessarily a major problem. However, one of the more critical issues is that antibiotic-resistant bacteria and resistance genes can be transferred into the environment—including soil and water—through livestock manure and livestock waste. Antibiotic resistance is not merely a process by which a single type of bacterium adapts to antibiotics; resistance genes can spread to other bacteria through mechanisms such as gene transfer between bacteria. In particular, when livestock manure—which may contain antibiotic-resistant bacteria, antibiotic residues, and resistance genes—is discharged into farmland and other areas, it can exert selective pressure for antibiotic resistance on microbial populations in the environment. Since resistance genes can be transferred to other bacteria during this process, problems originating on farms can spread to the broader environment via soil and water. In fact, international organizations view the issue of antibiotic resistance as one that connects humans, animals, and the environment, and they have identified reducing the discharge of antimicrobials and antibiotic-resistant bacteria from farms and livestock environments as a critical management task. Thus, managing the use of antibiotics in livestock is not only crucial for directly protecting human health but is also essential for reducing the spread of antibiotic resistance through the environment.
To address this potential threat, many countries have restricted or banned the use of antimicrobials for the purpose of promoting growth in healthy livestock and are managing disease prevention and treatment to ensure they are conducted according to stricter, scientific standards. In the case of Denmark, rather than imposing a blanket ban on antibiotic use for all livestock in 1995, the country gradually tightened regulations—for example, by banning avoparcin, which had been used as a growth promoter—and subsequently phased out the use of antimicrobials for growth promotion. As reports emerged during this process showing a decrease in antibiotic resistance rates among livestock, attention was drawn to the fact that policies aimed at reducing antimicrobial use can be effective in managing antibiotic-resistant bacteria. However, reducing the use of specific antibiotics does not automatically eliminate all antibiotic resistance, and outcomes may vary depending on the type of resistant bacteria, the livestock species, the drugs used, and the farm environment. Therefore, the current international trend is not simply to ban all antibiotic use, but rather to phase out non-medical uses—such as growth promotion—while limiting therapeutic, control, and, when necessary, prophylactic use to the minimum required, based on veterinary judgment and evidence.
In South Korea as well, policies to reduce the use of antibiotics on farms have been in place for some time. As mentioned in the original text, South Korea phased out the range of antibiotics permitted in compound feed between 2005 and 2011 and subsequently restricted the use of antibiotics via compound feed; since then, antibiotic use in the livestock industry has shown a downward trend. However, it is difficult to conclude that the risk of antibiotic resistance has decreased at the same rate as the overall reduction in usage shown in past data. This is because it is necessary to examine, in conjunction, which classes of antibiotics were used and in what quantities, to which livestock species they were administered and by what route, and how the resistance rates of the relevant bacteria have changed. In particular, since certain antibiotics, such as cephalosporins, are also important drugs in human medicine, their use in the animal sector must be carefully managed. Currently, the international community is also developing management systems that go beyond simply monitoring reductions in total usage to include surveillance of the types of antibiotics, routes of administration, purposes of use, and usage levels by livestock species.
Furthermore, it is essential to take into account that South Korea’s current regulatory framework has changed since the original text was written. Currently, in South Korea, veterinary antibiotics and antimicrobial agents that pose a risk to human and animal health due to misuse or overuse are designated as prescription-only veterinary drugs, and, as a general rule, these drugs cannot be sold without a veterinarian’s prescription. In particular, since the 2020 amendment, the scope of prescription-only antibiotics and antimicrobial agents has expanded, leading to stricter prescription controls than in the past. Therefore, it is inaccurate to assert that “even when administering antibiotics to livestock for therapeutic purposes, a veterinarian’s prescription is not required at all” or that “as long as antibiotics are not added to feed, they can be used indiscriminately to promote livestock growth.” However, since the existence of a prescription system alone does not solve the problem of antibiotic resistance, it is crucial to continuously monitor prescription and administration records, usage volumes, purposes of administration, compliance with withdrawal periods, and trends in the emergence of resistant bacteria at actual farms. Ultimately, it is necessary not only to reduce antibiotic usage but also to establish a system based on veterinary diagnosis and prescriptions to ensure that antibiotics—which are vital for the treatment of both humans and animals—are not used unnecessarily.
As mentioned earlier, the issue of inappropriate antibiotic use in agriculture and livestock farming is a complex problem that can affect not only human health but also animal health and the environment. Antibiotic resistance is not a problem that can be solved by a single country; rather, it requires a collaborative response across multiple sectors, as human healthcare, livestock farming, aquaculture, food production, and environmental management are all interconnected. In light of this, South Korea must also align with the international trend toward reducing antibiotic use by more systematically managing the prescription, dosage, and intended use of antibiotics administered to livestock, and by continuously monitoring the emergence and spread of antibiotic-resistant bacteria. The World Health Organization (WHO) and the World Organization for Animal Health (WOAH) also emphasize the “One Health” approach, which views human, animal, and environmental health as a single system. They recommend reducing the use of antimicrobials while simultaneously minimizing the occurrence of infectious diseases that require antibiotics in the first place through vaccination, biosecurity measures, hygiene management, and improvements to rearing environments. Farmers must also work to reduce the amount of antibiotics needed for treatment by improving livestock housing conditions and hygiene and strengthening disease prevention measures. Ultimately, the goal is not to eliminate the use of antibiotics unconditionally, but rather to use them appropriately for essential treatments while reducing unnecessary use. The issue of antibiotic resistance is no longer a problem confined to other countries; it is a challenge that the entire world must address together. South Korea, too, must establish and continuously manage a responsible antibiotic use system through the collaborative efforts of the government, the veterinary community, and the agricultural and livestock industries.
