Resistance isn’t futile

This week in Horse and Hound, they looked at the growing antibiotic resistance in horses, just as we get in human medicine. It also looked on what horse owners need to do to tackle this problem, a particularly interesting article for me to look at as I previously knew nothing about it!

On a daily basis, vets are faced with horses suffering from infections. Some are very serious – if the infection is not rapidly solved then the horse many die. However, thanks to the advent of antibiotics more than 50 years ago, vets could then treat bacterial infections effectively and with confidence.

Almost as soon as antibiotics were developed, it became clear that their ability to work was likely to alter over time. This was due to the evolution of resistance by bacteria to the actions of the drugs. Bacteria have an incredible ability not only to develop reisance to antibiotics, but also to transfer this resistance to different populations of bacteria. The end result is that, over time, antibiotics have become less efficient at killing bacteria. Consequently, diseases caused by bacterial infections become more difficult to treat. So how does this problem affect today’s horse owner?

Understanding the problem

While the issue of antibiotic drug resistance has been recognised for many years, it has only relatively recently started causing major concerns among vets. This is because drug companies have, historically been adept at producing new and effective medicines. Unfortunately, over time, even many new antibiotics have become less effective as specific resistance has developed. In the past few years, the problems of bacterial resistance to common antibiotics have been increasing dramatically in both human and in veterinary medicine. There are three central reasons for this:

Better care: Sicker horses ( and people) are more likely to survive, but require intensive treatment in large specialised hospitals. Such size able institutions, with high populations of the very sick, provide the perfect breeding ground for the development of the antibiotic resistance. Recent studies have demonstrated that antimicrobial drug resistance is a much greater problem in equine hospitals compared with horses treated in their stable or field.

Excessive use of antibiotics: This has developed in both veterinary and human health care. In human medicine this occurs, for example, when patients demand antibiotics for simple coughs, viral colds and sore throats. There has been a culture in veterinary care where antibiotics are frequently perscribed when they are not needed , in part due to owner expectation.

Lack of research: Compared with previous decades, there has been a large lack of progress in developing new antibiotics. The reason for this is simple – although there may be new discoveries, there is a perception that everything of use has been found. Both human and veterinary medicine have to make due with current drugs, to which resistance is rising. Antibiotic drug resistance is not yet at crisis point among horses but there are some specific areas of concern. The increasing diagnosis of MRSA infections in the horse, many of which occur in those that have recently undergone surgical treatments in equine hospitals is a big worry. Another growing concern is that the most common antibiotic used for oral medication, Trimethoprim / sulphadiazine, is frequently resistant to one of the commonest bacteria – E.coli – found in wounds after traumatic injuries. Equine vets are aware of how the situation has developed in both human and small animal veterinary medicine. They know it is likely we will soon be facing a similar problem when it comes to treating horses.

What can be done

The vet profession has, as a whole, received quite a lot of the blame for this worldwide problem. Excessive use of antibiotics by vets in food-producing animals is frequently cited as one of the major reasons why antibiotic drug resistance has become such a problem in human medicine. In the wake of criticism, there have been demands that new antibiotics – fluoroquinolones, occasionally used for horses in the UK, for example under the brand name Baytril, and third- and fourth- generation cephalosporins- are no longer made available to vets for animal treatment.

These antibiotics are sometimes used in horses and can be very useful in specific cases where no other drug is effective. This include bad joint infections, cases of severe respiratory infection (pleuropneumonia) and peritonitis (inflammation of the abdominal lining).

In December, the British Equine Veterinary Association (BEVA) produced specific advice relating to the responsible use of antimicrobials in the horse. This aims to ensure that these drugs are only used when necessary and appropriate. The pivotal piece of advice is to avoid the use of antibiotics unless essential and to ensure they are administered at the correct dose and for the full duration of the course. Equally, vets must consider routine testing to identify, record and monitor the bacteria that cause oriblems and to what antibiotics they may be sensitive or resistant. This usually only currently happens when the infection is very serious-such as joint/synovial infections-or cases that have not responded as expected to initial treatment.

More powerful modern antibiotics should be kept in reserve and used only when laboratory tests show that there are no alternatives. All equine vets should develop protocols to ensure appropriate use of drugs. A recent survey showed that less than 1% of vets worked in practices with a written antimicrobial use policy, which is certainly a cause for concern.

In the horses we still have the opportunity to affect dramatically how we use antibiotics and ensure we have effective medication for the future. To do this requires some change in culture bu the veterinary profession. It also require awareness by owners that antibiotics cannot be used without consequences. In many instances, antibiotics will no longer be used, even where they may have been routinely administered in the past such as minor wounds or coughs. This joint approach should safeguard both our access to and the effectiveness of, these important drugs.

A pressing problem I have found very interesting about. In a couple of years it seems this will directly effect me, being a horse owner. Useful to have some background on the topic.

Next article next Thursday!


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