Steve Pulley, Cambridgeshire. asked:
As I understand, there are some concern with too much antibiotics being used in cattle and so on. My question is, can those antibiotics carry over to humans particularly if the meat is cooked? In other words, those cooking in the meat from an animal that's had a bit much antibiotics, does the cooking destroy the antibiotic, or make ineffective in humans, so as we don't inadvertently give the bacteria opportunity for resistance?
Paul - A lot of antibiotics are heat labile so they're destroyed by the cooking process but often now, there's a lot more regulation in terms of using antibiotics and in veterinary medicines so there's no overlap with human antibiotics or as little as possible.
Chris - What about the implication of using antibiotics in terms of, itís not just this country but, other countries often put antibiotics into their animals? What are the implications for resistance and the spread of resistant organisms into humans because of that practice?
Paul - There is a lot of evidence to suggest that some of the antibiotic resistant Staphylococci acquired the resistance mechanisms from related organisms that were found in cattle, possibly due to the use of antibiotics in those animals. However, there's been a lot tighter regulation across the world now, as people realise that this was a possible outcome.
I've always heard that bacterial resistance was caused by antibiotic use in farm animals, but I question that. I worked as hospital microbiologist, and many human strains of staph and other organisms are resistant to penicillin, and penicillin isn't generally relied on to treat staph, but it still is used for strep throat. I married a beef farmer and was surprised to learn that vets still use penicillin effectively. So I don't think drug resistant strains are coming from cattle. cheryl j, Wed, 30th May 2012
One of the reasons drugs like penicillin are used in livestock is that it is relatively easy to give injections. In humans, on the other hand, drugs such as amoxicillin in tablet form are preferred, although I presume there is a significant amount of crossover between the two.