If you’re part of the somewhat niche world of veterinary pharmaceuticals, you may have heard that the 2021 sale of antibiotics for use in food-producing animals was the lowest ever. For the rest of us, let’s discuss this surprisingly important report. What does the report say? Why are low sales of antibiotics a good thing? What does this mean for the future?

Table of contents

Recapping Antibiotics

As a reminder, antibiotics are any substance that kills or slows the growth of bacteria. Antibiotics are one class of the broader group antimicrobials (a substance that kills or slows the growth of microorganisms including bacteria, viruses and fungi). Humans understood the infection-stopping properties of moulds and other antibiotic substances for millennia; but it’s modern medicine where antibiotics really revolutionised healthcare.

Since their formal discovery in the 19th-20th centuries (most notably Alexander Fleming with penicillin), antibiotics have been used to treat bacterial infections, preventing the suffering and death of countless millions of people. Where before a wound could lead to loss of life or limb, most infections can be now managed. Soldiers in war who were far more likely to die from infection than bullets are now protected when bacteria contaminate their wounds. Patients with HIV, cancer and other immunosuppressive diseases are now better protected against common bacteria that may harm them. Organ transplantation, caesareans, neonatal care, orthopaedics, brain surgery and more procedures are now relatively safe. 

Veterinary use

With animals being so intertwined in our lives as food, workers, pets, for transport, sport and more, it didn’t take long before antibiotics were being used in veterinary medicine too. Today they are one of the most common drugs used by vets for infections. Antibiotics are also used in farm animals as growth promoters (the theory being they kill off bad bacteria in the gut, promoting good bacterial growth and encouraging growth of the animal). However, this has been banned in the EU since 2006 and remains so in the UK post-Brexit (though the legislation is shakier). It is still common in some parts of the world.

It is impossible to overstate the importance of antibiotics to the modern world. Without antibiotics, millions more people and animals would suffer and die each year, and modern medicine would cease to operate effectively. Unfortunately, this awful possibility may be closer than you think.

What Does the Report Say?

Before we get gloomy, we’ll explain what the report contains.

The report was written by the Veterinary Medicines Directorate (VMD), a government organisation responsible for the legislation and use of veterinary medicines, to ensure animal health and welfare is maintained. Their report is the “UK Veterinary Antibiotic Resistance and Sales Surveillance Report” (UK-VARSS 2021), published November 2022.

Positives

The headline statement is that the overall sales of antibiotics in food-producing animals has dropped to the lowest level ever of 28.3mg/kg (this means on average for every kilogram of food-producing animal, 28.3 milligrams of antibiotics were used). This is a 55% drop since 2014. On top of this, the sales for antibiotics in all animals has dropped to 212 tonnes, a 52% drop since 2014. Furthermore, the sale of Highest Priority Critically Important Antibiotics/HP-CIAs (drugs that should be reserved for use in humans, and only used in animals in exceptional circumstances) has also dropped to 0.12mg/kg, down 18% since 2020 and 83% since 2014 – they now make up only 0.4% of total antibiotic sales. Antibiotics for food-producing animals make up 81% of the market, with only 8% for companion animals (pets, including horses). The rest are products licensed for both groups of animals. 

Other positives noted by the report were that the use of injectable antibiotics has increased slightly and now makes up 23% of all sales for food-producing animals. This implies that individual treatment is becoming more popular versus blanket water or feed administration. (Though injectable antibiotics are still only the third most sold form of antibiotic in farm-animals, after oral or water-based and in-feed based). The report does note that in-water antibiotics are considered better for antibiotic control than in-feed antibiotics, and in-feed use is dropping in the pig and gamebird industries.

It was also noted that no critically important antibiotics were used in the duck, laying hen and salmon industries, while their use fell in pigs, turkeys, gamebirds, cattle and trout (as well as dogs and cats), in 2021.

Negatives

There is some negative data however.

The sale of antibiotics in salmon farming has increased 168% since 2017, and is the second highest at of all food-industries at 43.1mg/kg. However, Salmon Scotland stated that the increase from 2020-21 was likely due to their increased use during the marine phase of production (salmon farming moves between fresh and marine-water environments as the fish grow). This would not explain the general increase since 2017, as salmon fishing is a 3-year cycle. They do note that the overall use of antibiotics is low, with only 8.5% of fresh and 4.9% of marine farms treated in 2021.

The sale to gamebirds and turkeys also increased since 2020. However, their overall use in turkeys has dropped 81% since 2014, and in gamebirds since 2017. The British Poultry Council noted that the increased use of antibiotics in 2021 may have been due to a lack of a vaccine for a specific bacterial infection, necessitating the use of antibiotics instead.

There was also the fact that 34% of antibiotics were sold as in-feed forms, which are highly non-specific and thus a poor use of antibiotics. However, as stated above, their use has dropped and oral/water antibiotics are now more popular, with injectables catching up. 

Unfortunately, the worst trend was found in companion animal medicine

The sale of antibiotics in dogs, cats, horses and similar pets has unfortunately increased by 0.5 in 2021 to 3.1 days in dogs (antibiotic use in companion animals is recorded as days per year an animal has antibiotics), and by 0.3 to 2.4 days in cats. Even more concerningly, the second-most sold antibiotic for cats is cefovecin; a protected third-generation cephalosporin that should only be used when absolutely necessary. 41% of sales for cats were cefovecin. Overall, though, use of critically important antibiotics has decreased by 41% in dogs and 24% in cats since 2014.

Summary of Report

In summary, although specific industries and areas of food-production have shown fluctuations, the overall sale of antibiotics to these animals has dropped considerably since 2014. And although their sale to companion animals has increased this year, overall sales since 2014 have also dropped. Though much work is to be done, this is something vets and industries everywhere should be pleased about.

But why? Why are less antibiotics sold a good thing? Let’s finally get into antimicrobial- and antibiotic resistance.

Antimicrobial Resistance

Antimicrobial resistance (AMR) is where microorganisms, including bacteria, start to protect themselves against antimicrobial substances, through random mutation. Antibiotic resistance is the type of AMR specific to bacteria and antibiotics. 

Random mutations occur all the time when microbes reproduce

Many of these mutations have no effect, or may even cause harm to the organism. Some, however, may provide protection from antimicrobials – a good example is bacterial resistance to penicillin. Penicillin contains a structure called beta-lactam. Certain bacteria have randomly acquired a mutation allowing them to create beta-lactamase enzyme. This enzyme breaks the beta-lactam structure of penicillin, destroying the antibiotic, making it useless against these bacteria.

A single mutation in a single microbe is unlikely to lead to widespread AMR. However, when antibiotics are overused, more and more susceptible microbes are killed, leading to only microbes with protective mutations remaining. These microbes are free to reproduce; producing populations of resistant microbes that the antibiotics cannot kill. This is leading to once-susceptible microbes being mutated so heavily that we struggle to treat them. MRSA is the best-known example of these.

AMR is not some scary future scenario – it is happening now

In the USA alone, almost 3 million people are infected by resistant bacteria, and 35,000 die, each year. The United Nations predicts that by 2050 10 million people a year could die worldwide as a result of AMR. One biosecurity researcher said “I don’t think I’m exaggerating to say it’s the biggest human health threat, bar none. Covid is not anywhere near the potential impact of AMR. We would go back into the dark ages of health.”

Though a natural occurrence, human overuse of antimicrobials (among other factors) is directly leading to AMR. This includes the veterinary field, where the overuse of antimicrobials creates resistant bugs that can infect human farm or vet workers, spread into the environment, contaminate food, and even be spread via faeces into soil. If AMR leads to antimicrobials becoming useless, this will affect pet and livestock welfare, food security and human health immensely. 

If this all sounds like more doom and gloom, we’re sorry to say it’s true. But let’s move back to the positive and return to the VMD report.

Why The VMD Report is Important

As AMR has become a critical issue, the WHO, UN and other international organisations, as well as national organisations, are starting to legislate the use of antimicrobials. We’ve already seen this with the EU’s ban on antibiotics for growth promotion in 2006. The UK veterinary industry is also following suit and the VMD report reflects this.

What the VMD report is showing is the UK food-production and companion animal sectors’ responses to AMR legislation. Since 2014, there has been a significant drop in the sale of antibiotics in these areas, meaning less antibiotics are being used that would otherwise lead to AMR. The report demonstrates this by showing how the resistance of E. coli in pigs is generally slowing or even decreasing, with little resistance to those critical drugs. Overall, 34.6% of E. coli were susceptible to all antibiotics tested, while 37.1% were resistant to multiple antibiotics, down from 50.6% in 2015. Salmonella showed a similar trend in pigs and poultry. This demonstrates how good practices can stop and even reverse the trend of AMR, and how preventing the use of protected antibiotics in all but the most extreme cases will protect their efficacy, so they can be used to safeguard human lives. 

There was no information regarding AMR in companion animals, but we know that an increased sale of antibiotics will be contributing to increased AMR. The longer AMR can be slowed or reversed, the greater chance new antimicrobials can be developed to fight future infections and save lives. 

A Long Way to Go?

The government response to the report is wholly positive, and we agree that the reduction in antibiotic sales and AMR should be commended. Despite these very positive trends, AMR is still on the rise – vets should always be self-critical, and it is important to accept there is a lot more we can be doing, both within the UK and worldwide. To slow down AMR, there are steps everyone must take.

As vets…

It is important we remain up to date with current knowledge on antibiotic use and AMR, ensure that antibiotics are not prescribed when unnecessary, proper testing is done to ensure the correct antibiotics are used, we preserve critically important antibiotics for animal use only when absolutely necessary, and educate clients on the proper use of antibiotics for their pets. As per the report, the companion animal sector has a lot further to go in minimising the sale of antibiotics, in particular with protected antibiotics. 

As owners… 

You should understand when antibiotics are or are not needed, know how to use them appropriately, make sure you finish courses completely, do not use antibiotics on other animals or humans without advice from a vet, and reduce the risk of your pets getting bacterial infections with proper diet, safety and preventative healthcare. All this advice applies to antibiotic use on yourself when prescribed by a doctor too.

The dire future predicted by the biosecurity researcher is not inevitable, and scientists around the world are scrambling to combat AMR. But to prevent the worst consequences of AMR, every person must consider how they use antibiotics. According to the VMD report, parts of the UK veterinary industry are showing good positive steps in the right direction. We have many more steps to take. 

Further Reading:

VMD Report:

Antibiotics:

AMR: