The increasing threat of antibiotic resistance is one of the biggest challenges to human health in the 21st century. Previously curable infectious diseases are becoming untreatable, with the risk of widespread morbidity and mortality. Resistant infections could potentially spread throughout the world in a short space of time, thanks to the recent growth in international trade and travel.
Antibiotic resistance is a well understood issue
The science behind antibiotic resistance is well known at this stage: when bacteria are exposed to an antibiotic, the more susceptible organisms are killed, while any resistant bacteria survive. These survivors can then replicate, passing on their resistance to the next generation of bacteria.
Inappropriate use of antibiotics is one of the main drivers of this problem, including under-use, over-use and mis-use, in both human and veterinary medicine. A concerted, co-ordinated effort is needed by many parties to tackle this problem; this includes prescribers, pharmacists and dispensers, the pharmaceutical industry and the public. Policy makers at local, national and international levels also need to play a strong role. The World Health Organisation (WHO) and many other international bodies are deeply engaged with this work.
Veterinary antibiotic usage is under the spotlight
There are several ways that veterinary medicine is involved. Perhaps the most significant aspect has been the use of antibiotics at sub-therapeutic levels as “growth promoters” in situations where animal husbandry is less than optimal. The deliberate use of “weaker” concentrations of antibiotics in this way can select for bacteria that have the potential to be resistant to a particular antibiotic, and these resistant strains can then spread to humans.
This “growth promoter” use of antibiotics is no longer relevant to the UK. We have some of the strictest regulations on antibiotic use in the world, as well as a deep-rooted culture of responsible use: the use of antibiotics as growth promoters was stopped right across the EU in 2006.
However some health experts do have concerns about the widespread use of potent antibiotics in the animal world at all. There is sometimes a sense that the latest and best antibiotics should be reserved only for human use, and that vets should not have access to prescribing and dispensing these drugs. This is a theoretical position rather than a proven hypothesis, and vets worry that there is a risk that they could be unnecessarily stopped from using medication that is essential to the health and welfare of their patients.
New study shows that improved husbandry can allow reduced use of potent antibiotics
A recent report in the Vet Record has added an interesting angle to this debate: the study demonstrated that dairy cattle health and welfare can be maintained – and even improved – after stopping the use of the highest priority critically important antimicrobials (HP-CIAs) including fluoroquinolones and third- and fourth-generation cephalosporins.
The six-year study involved seven dairy farms in south-west England that underwent an active process of education and herd health planning meetings with vets from the University of Bristol and Surrey, and at the same time the farms achieved a significant reduction in antibiotic usage.
Many farm vets – and indeed companion animal vets – are well aware of concerns about antibotic resistance, but at the same time, they may feel under pressure to respond to farmers’ – and pet owners’ – expectations. The issue is particularly pertinent to farm animal practice: farmers have an economic need for their animals to be healthy, and this can lead to vets feeling strong financial pressure to perform. The fact that the antibiotics are being used in food animals also has a higher risk of transfer of resistant bacteria to humans compared to use in companion animals.
In the Vet Record study, changes to prescribing practices were made alongside various strategies recommended by vets to improve animal management and husbandry on the farms. The changes that were put in place were highly successful. In 2010, third- and fourth-generation cephalosporins were being prescribed to all seven farms in the study; by 2015, they were not used in any.
The study found that over this period, milk yield and fertility parameters remained stable, while the calving interval and mean number of days from calving to conception decreased. The clinical mastitis case rate decreased on five of the seven farms, while the percentage of cows scored as lame decreased on all farms.
Farm vets, as educators and instigators of changed practices, have a strong role to play
The conclusion of the report was positive: farm vets are well-placed to implement changes in prescription practice, as well as to educate and motivate farmers and farm staff to adjust their expectations.
If we ignore the threat of antibiotic resistance, we could soon be back to the days of the early twentieth century, with life threatening bacterial infections becoming commonplace again. It is easy to take the power of antibiotics for granted. We all need to keep working hard on this topic and this report from the Vet Record is a positive reminder that when the right steps are taken, progress is possible.