Sir, - I have no doubt that all Dr Beechinor stated (October 15th) is correct. However, regardless of whether or not antibiotic usage in veterinary medicine is supervised and monitored, it remains a fact that the more that antibiotics are used the more antibiotic resistance in micro-organisms will develop.
The evolution of life forms, bacterial or otherwise, is determined and moulded by external factors and, in the case of noxious agents (antibiotics with regard to bacteria), the life form is either injured or dies or ir adapts through genetic changes and deveops the ability to resist. This resistance is genetically coded and can be transferred to other life forms (not necessarily of the same subspecies), and in time may re-adapt if circumstances change. But experience has shown that more and more exposure of bacteria to antibiotics makes the inevitable genetic change more likely.
It has been shown that genetic change in bacteria associated with the development of resistance is of at least two types. In one, natural recombinational genetic events produce all sorts of changes, and some of these changes are useful to the bacteria and, in the case of resistance, bad for us. The other change is due to bacterial "viruses" or transposons which can be viewed as roaming pieces of genetic material just waiting to invade a new host and set off new genetic events. If doctors and vets weren't killing off bacteria with antibiotics these genetic events wouldn't be as important because the usual bacteria would act as competitors in greater numbers to these new breeds and therefore not allow their development.
It was never my intention to apportion blame to any individual group for the development of antibiotic resistance in bacteria. However I did wish to clarify that the development of bacteria which are highly resistant to most antibiotics is not the responsibility of general practitioners and that we all, doctors and veterinary surgeons alike, are responsible for introducing newer chemicals into the natural ecosystem. We should all step back and look at the consequences of what we do. - Yours, etc., Dr D. Rafter,
Rathgar,
Dublin 6.