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Vet Talk

Antibiotic Resistance: What’s in it for me?
February 18, 2014 (published)


You can’t open a newspaper or magazine these days without a headline fighting for your attention, screaming about antibiotic resistance. You’ve probably heard of MRSA (methicillin-resistant Staphylococcus aureus), but the alphabet soup of resistant bugs is growing to include VISA (vancomycin-intermediate Staph aureus), VRSA (vancomycin-resistant Staph aureus) and a horde of other bad guys.

So, what is antibiotic resistance and what does it mean to the average person and the average pet? Where did it come from and how did it get so bad?

A little history on antibiotics is in order to help explain the problem. Antibiotics have only been around for about 100 years. Most of the early antibiotics were derived from molds. They were the molds' way of fighting off bacteria: some molds produce compounds that kill bacteria that compete for the same resources that the molds were.

MOLD: I am feeling a tad peckish. I think I will eat this tiny delicious crumb of bread right here.

BACTERIA: I believe I shall also partake of this delicious morsel.

MOLD: (Squirting antibiotics at the bacteria) I think not.

In some lab somewhere, a bespectacled and pocket-protected scientist noticed that there was a bacteria-free zone surrounding mold colonies and thought “hmmmm…that’s odd! Wonder what’s causing that?” and the modern antibiotic era was born. These bacteria-fighting compounds were isolated and synthesized and then used to treat human bacterial infections, which brings us to Important Point #1: Antibiotics work only against bacteria.

All of the maladies caused by viruses, such as the flu (influenza virus), the common cold (some 200 kinds of viruses working together), and rabies, just to name a few, thumb their noses at antibiotics.

This is one of the central points behind the development of antibiotic resistance: if you are treated with antibiotics for a viral condition, you not only don’t treat the main problem, you’re fueling the resistance problem. More on this below.

Antibiotic resistance means that, over time, the power of antibiotics to kill bacteria wears off. Not due to any change in the antibiotics, but because the bacteria can fend them off better. The bacteria change, and in essence evolve to become stronger and resistant to the effects of the antibiotics. So the antibiotics, and the people who use them, cause this.

This brings us to Important Point #2: Overuse of antibiotics is what drives resistance. This happens through MDs and veterinarians prescribing antibiotics ‘just in case,’ and also in livestock food production. (Antibiotics added to feed for chickens, cows and pigs makes them grow bigger, and faster.)

The way antibiotic resistance develops is like this: if antibiotics are used when they aren’t needed, they kill off the weaker bacteria that we all harbor. Even if they’re not causing a problem, they’re there, in your sinuses, in your gut, on your skin, just lounging about. The ones killed off are the weak ones – the ones that have not ‘learned’ to be resistant – leaving only the strong ones, the resistant ones. Those resistant ones are the ones that rise up the next time you have a bacterial infection, and they aren’t going to respond to the antibiotic that was used last time. So you need a different and more potent antibiotic each time. A sort of arms race develops, with ever increasing levels of resistance requiring ever more potent drugs. Obviously, this is a gross oversimplification, but this is the skeletal structure of how it works.

The overuse issue is huge. MDs and veterinarians know it, but many in the public don’t. Clinicians feel immense pressure from parents, patients and pet owners to prescribe antibiotics for a wide variety of conditions that don’t need them. Ear infections in kids are a classic example – many are what is called ‘self-limiting,’ meaning they will go away on their own with no intervention. The body’s ability to take care of itself is amazing, and we really don’t need to intervene as much as we think we do. But parents pressure doctors to prescribe unnecessary medicine for ear infections, with the best of intentions. And when the disease gets better in 24-48 hours (which is the usual timeframe for antibiotics to work) the improvement is credited to the antibiotics, not the self-limiting nature of the disease. It would have gotten better on its own, but the temporal link of the antibiotic prescription to the improvement only strengthens the impression that antibiotics are needed in every case. In reality, it is only a small fraction of ear infections that need antibiotics to improve.

Many people feel that the trip to the doctor or veterinarian just isn’t complete without that little vial of pills or bubblegum-flavored liquid. And good luck to the poor clinician who doesn’t prescribe antibiotics ‘just in case,’ who is then faced with a patient who gets sicker! Even if the disease is viral, the appearance that the disease got worse because they didn’t prescribe antibiotics, rather than because the disease progressed, is hard to shake and fingers start pointing. I have had many quizzical stares from pet owners when I have sent a pet home without antibiotics, even if they have a fever or some other sign of (probably viral) infection.

So here’s Important Point #3: Don’t demand antibiotics. If your doctor thinks they are not needed, go with it. Some indications that antibiotics are needed include a positive culture result (where you actually grow bacteria in a culture dish), yucky green discharge from wherever (pus, which is a mix of dead white blood cells and dead bacteria) and certain changes on labwork. A complete blood count, or CBC, can often show a high, or even worse, a low white blood cell count and signs that the white blood cells are all beat up and losing the battle. Just a high white cell count or a fever are not signs that a patient needs antibiotics. Many things besides bacterial infections can cause a fever – even cancer can cause a fever!

In some special and very select cases, such as a life-threatening condition or a patient with a poor immune system, we will indiscriminately use antibiotics (what we call ‘shotgun’ therapy). However, these are - and should be - limited to a very small number of cases, and doctors should try and match the antibiotics to their best guess as to what bug is causing the problem.

As an example from my professional life, I have seen many, many cases of pets treated with antibiotics for repeated urinary tract infections, or UTIs. In some cases, these pets didn’t actually have any infection at all. They had a stone in their bladder, causing the same signs as an infection: blood in the urine, frequent and urgent urination. But the right tests were not done, and the simple but wrong solution of a $15 antibiotic prescription was chosen. Possibly this was because the doctor did not want to run the proper tests, for fear of being accused of ‘upselling’ procedures, or the owner declined the tests to save money.

After enough cycles of unnecessary antibiotics - and hopefully by now you can see what happens - when the pet does actually get a UTI, instead of a weak bug that would have responded to some entry level antibiotics, we are now dealing with a voracious ‘superbug’ that eats normal antibiotics for lunch and can only be tamed with expensive and sometimes dangerous drugs. This is not an isolated, unusual, or rare problem: I have been faced with many culture results showing an “R” (for resistance) for every antibiotic in the hospital pharmacy. In some cases, there are no drugs left to treat the infection, in others only drugs that are unable to be used for pets, or are too expensive for pet owners to afford. In the past 5 years, this trend has increased to the point that I dread reading a culture, for fear of having to go back to the pet owner and say ‘there’s nothing more to be done.’ I am scared.

We'll only win this battle if we start using antibiotics less and start using them smarter. We need to become the higher vertebrate here, and not give in to our moldy urges to throw pills at everything. Limiting antibiotics in animal feeds and giving fewer unnecessary prescriptions for both man and beast are a start. It also means you should finish a course of antibiotics (to kill ALL the bugs, not just the wimpy ones) and we doctors should prescribe at the right dose. It means more targeted therapies to determine if a problem really is bacterial in origin – cultures, blood tests, plus some new things coming down the pike that the pocket-protected scientists are dreaming up. We'll also need new antibiotics to fight infections, but that’s only part of the solution. People and doctors will have to work together, learn to trust and break a few bad habits. We have a lot to learn from the molds, but I am certain that we can do it.

The future depends on it.


 
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