Antibiotic resistance

July 17, 2014

Antibiotic resistance is a growing concern among the Human and Veterinary Medical Professions.

Since the first discovery of penicillin by Alexander Fleming in my home town of Edinburgh in 1928, there has been an arms race between scientists and bacteria and there are now some worrying signs that the bacteria are starting to win.

When bacteria breed by a process known as replication, mistakes can happen randomly as the genetic information is copied from one generation to the next. Antibiotics exploit a weakness in the bacteria to either kill or damage the bacteria. As there are billions of bacteria in existence, each replicating rapidly, and occasionally making mistakes, very occasionally, a bacterium will evolve that closes the loop hole that was being exploited by the antibiotic.

If a population of bacteria is exposed to an antibiotic, all the susceptible bacteria will be killed but any that have mutated and are no longer susceptible will survive. This means that the antibiotic will not get rid of all the infection.

Even more worryingly, because the antibiotic has killed off all the susceptible bacteria, the new resistant bacteria has less competition and can multiply even more quickly and all its offspring are also likely also to be resistant to the antibiotic.

While we still have very effective antibiotic drugs which work in the vast majority of cases, antibiotic resistance can be a real problem.

There are few new antibiotics that have been developed in the last 25 years or so and there are few new molecules that are in development. When an antibiotic that has worked well for decades starts to become less effective, there tend not to be new antibiotics waiting to take their place.

Since I first started in Veterinary Practice 19 years ago, we have seen a steady rise in the incidence of antibiotic resistance.

At Donaldson’s, we now do more antibiotic sensitivity testing than ever before. This involves taking a swab sample from the affected area and sending it to the Laboratory to establish exactly what bacteria are present and which antibiotic the bacteria are sensitive to. This allows us to accurately determine the most effective course of treatment however there is inevitably a delay while the tests are conducted.

The battle against antibiotic resistance is a worldwide issue and unfortunately, in some countries, antibiotics are freely available for individuals to self-prescribe. In this country, antibiotics availability is limited so they can only be prescribed by a suitable professional. It is essential that antibiotics are only used when there is a genuine infection present, that they are used at the correct dose rate, and that the course is maintained for long enough to get rid of the infection.

Without effective antibiotics, human and veterinary medicine could return to the dark ages where patients die of conditions that we have confidently treated for nearly a century.

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