World Health Organization says antibiotic resistance a threat to human health
The World Health Organization (WHO) says overuse of antibiotics in animals is contributing to increasing levels of drug resistance in humans, which is leading to serious health implications
The Ontarion was able to speak with Scott McEwen, a professor in the department of population medicine at the Ontario Veterinary College (OVC). We spoke to McEwen about some of the risks of antibiotic resistance and why it is increasingly present in farm animals.
Bukola Toluyemi: Why do we use antibiotics on animals?
Scott McEwen: We use drugs in veterinary medicine to treat bacterial infections of all types of animals. When you have an animal that’s sick with a clinical infection [caused by] bacterial infection a veterinarian will administer antibiotics to treat that.
Another type [of antibiotic use] is for prevention; this is when antibiotics are administered when there is thought to be a high risk for a group of animals being exposed to bacteria and developing infections. The intent is to prevent that from happening.
The third major type of [antibiotic use] is for food animals, not for cats or people. The use of antibiotics [on farm animals] is to promote growth or to improve feed efficiency. You administer antibiotics and the animals grow at a faster rate or get to market weight with less feed than if you didn’t use them.BT: What are the health risks of using antibiotics?
SM: The bigger issue is around antibiotic [resistance]; that’s a separate health issue. There’s been a lot of controversy and debate around this. It’s been debated for almost as long as antibiotics have been around. Alexander Fleming, the person who discovered penicillin back in the 1930s, observed that bacteria became resistant after a period of time of being exposed to [antibiotics]. So we’ve known that when we give antibiotics to any sector (that’s people, animals, sometimes even plants), whenever we use them there is a chance that there will be resistance.
There’s been a heightened concern about this in human health because there are infections of people where there are very few, or in some cases no antibiotics, left that are effective because the bacteria have become resistant to almost everything. In human medicine this has become very serious, especially in hospital settings, but even in community settings.But in veterinary medicine there’s not so much a sense of crisis, I don’t know why that is. There are some animal sectors where resistance is a problem, but is not that severe. The implications are that there is a sense of urgency to do something about resistance within humans. It’s been slower to develop that urgency in veterinary medicine, but it’s happening, so now there is increasing pressure to reduce transmission of antibiotic resistance from animals to people.
BT: How is bacteria developing resistance? Is this something to be concerned about?
SM: Now the big concern is the quantity of antibiotics used in food animals in agriculture, particularly in growth motion and disease prevention. The quantities used [in growth motion and disease prevention] are much larger than quantities used for treatment. That’s because for growth motion, and often for disease prevention, the antibiotics are given to the entire herd of animals, and often for fairly long periods of time. These factors are important in resistant selection.
It’s not really possible to say how much the antibiotic resistance problem in people comes from animals, but I think it is fair to say that for these foodborne enteric infections, antibiotic use of food animals contributes [to antibiotic resistance]. And it may contribute indirectly to other types of resistance through the contamination of the environment by resistant bacteria.We know now that antibiotic resistant genes can be transferred to other bacteria. Once [antibiotic resistant genes are] out there, then we lose track of them, and they may well circulate around. So there are other pathways [to the growing crisis of antibiotic resistance in humans].
There’s been a lot of attention focused on trying to stop this antibiotic use for growth motion and, if possible, to stop administering antibiotics in healthy animals. The idea is to try to limit the exposure of antibiotics in food animals until they really need them.
Photo Courtesy of Uncyclopedia