Antibiotic Resistance

One of the biggest issues facing both human and veterinary health is that of antibiotic  resistance. Experts believe that, if the issue is not addressed now, our commonly used antibiotics will no longer be effective in a very short time.

Just what is antibiotic resistance and how does it occur? Antibiotics are chemicals, originally derived from bacteria, that inhibit other bacteria. However bacteria, by continual exposure, can develop resistance to noxious stimuli such as antibiotics and they have the ability to pass this resistance on to other bacteria. They do this not only when they reproduce but they also can pass the genes along from one bacterial cell to another, even to a different species of bacteria, so that the process can be extremely rapid.

Every time we use an antibiotic we run the risk of increasing resistance. Antibiotics do not so much as cause resistance in themselves but select for it. If we knock out all the sensitive organisms and leave a set of resistant bacteria then these can multiply rapidly so that the whole bacterial population is now resistant to our arsenal of drugs.

What we are now facing is not just the fact that drugs we have in use for our animals may no longer be effective, and that scenario is bad enough, but also the fact that this resistance can transfer to organisms that cause disease in the human population. This would be akin to a return to the pre-antibiotic era when common illnesses and simple surgical procedures would be life threatening.

It has been estimated that by 2050 antimicrobial resistance will be the most common cause of death in the human population, outstripping cancer and heart disease, if nothing is done to limit its spread. So the issue is serious.

What can we do about it? Already health professionals, including veterinarians, are assuming more responsibility and adopting prudent use techniques. These include using the correct antibiotic for each specific situation and only administering when absolutely required. It also means not using antibiotics needlessly or “just in case.”

It was once common practice on studs to give every foal at birth a dose of penicillin to guard against navel ill. This is totally unnecessary as treating the navel with a suitable antiseptic such as iodine works just as efficiently. There are other problems, such as foot abscesses, where antibiotics have no effect on recovery rate so are not indicated. In addition many respiratory problems are viral in origin and antibiotics do not work against viruses.

There is no such thing as ‘stronger’ antibiotics, just choosing which antibiotic is effective against which particular organism. Therefore prudent use requires knowledge of the particular disease and which antibiotic will be the most effective in a specific instance. This makes the medical professional, i.e. the doctor or the veterinarian, the person responsible for antibiotic stewardship.

Horse owners can help in many ways. Guarding against disease by limiting contact with other animals is one major way but this of course is difficult with sport horses. Hygiene is a major factor so cleanliness and appropriate disinfection techniques are essential prerequisites for anyone involved in stables or horse transport. Vaccination programs also reduce disease instance and antibiotic demand.

A large problem in the past, in both human and veterinary medicine, has been clients demanding antibiotics being prescribed by the health professionals. This is seen as a practice that must cease and already doctors are taking this stance.

Animal owners need to realise that antibiotics are not panaceas and should not put pressure on a veterinarian to prescribe them. It may be an important race coming up but the veterinarian is still best to judge whether antibiotics are indicated. If the animal is that ill that it requires antibiotics it is not fit to race anyway.

We, who have enjoyed the benefits of living in the antibiotic era, have a responsibility to change our ways if we wish our grandchildren to live longer than our grandparents.


Dennis Scott is a veterinarian with a background in pharmacology. He is a member of the Equine Health Association, the antimicrobial leadership group of NZ Veterinary Association and the advisory group to the World Veterinary Association.