What is Antibiotic Resistance?

L. S. Wynn
L. S. Wynn

Antibiotic resistance is a phenomenon in which microorganisms undergo a genetic mutation that allows them to withstand the effects of antibiotic agents designed to kill them or render them incapable of reproducing. The concept is perhaps most commonly discussed in terms of illness and disease. When a disease becomes antibiotic resistant, it is often considered incurable, and can pose a serious public health threat as a consequence. There are a couple of reasons why resistance happens, and it’s usually seen from a scientific standpoint as a normal part of pathogen adaptability and life cycle. Many researchers have suggested that human society’s broad reliance on antibiotic medications has or will serve to accelerate what would otherwise be a slow process of change, though, and many health activists have called for more reviews and controls governing how these powerful medications are used.

A Salmonella bacterium. Some strains of Salmonella can develop antibiotic resistance.
A Salmonella bacterium. Some strains of Salmonella can develop antibiotic resistance.

Understanding Antibiotics

In general, antibiotics are chemical agents that specifically target certain bacterial strains. They disable the bacteria by preventing their reproduction and growth. There are many different “families” of antibiotic drugs, and they’re widely used to cure and calm infections in humans and animals alike. In most cases they are very effective. Bacterial strains that have been progressively killed off by certain antibiotic agents can sometimes change their genetic makeup over time, though, which can make them harder for the antibiotics to target. This makes the medications less effective and, ultimately, not effective at all. This is what’s known in the medical community as “resistance.”

Over prescribed antibiotics can cause a resistance.
Over prescribed antibiotics can cause a resistance.

How Resistance Happens

Resistance develops as a result of natural selection. The antibiotic action is an environmental pressure, and those bacteria with mutations allowing them to survive will live on to reproduce. They will then pass this trait to their offspring, which will be a fully resistant generation. Another way of putting this is that resistance is an entirely expected and natural part of bacterial lifespan. Most organisms adapt and change as a result of environmental pressures, and bacteria are no exception.

Prescribed antibiotics may not cure an infection with those who are experiencing antibiotic resistance.
Prescribed antibiotics may not cure an infection with those who are experiencing antibiotic resistance.

The biggest concern most scholars have with resistance isn’t that it happens, it’s the speed at which it seems to be happening today. Diseases often adapt and change much faster today than they have in the past, which has caused some experts to worry that the drugs they rely on to treat common illnesses might soon simply stop working.

Resistance typically happens faster the more frequently a certain pathogen comes into contact with an environmental threat. Practically speaking, this means that the more often an antibiotic is used, the faster bacterial strains will adapt to exist alongside it. Several studies have demonstrated that modern patterns of antibiotic usage can have a dramatic affect on the prevalence of resistant organisms. Other factors contributing to resistance include incorrect diagnosis, unnecessary prescriptions, improper use of antibiotics by patients, and the use of antibiotics as livestock food additives to ward off infection before it happens.

Common Examples

Staphylococcus aureus, also known more generally as Staph aureus, is one of the major resistant pathogens. It is found on the mucous membranes and the skin of around a third of the population, and is extremely adaptable to antibiotic pressure. It was the first bacterium found to be resistant to penicillin, and was discovered just four years after penicillin began to be mass-produced.

Penicillin-resistant pneumonia or pneumococcus, caused by Streptococcus pneumoniae, was first detected in 1967, as was penicillin-resistant gonorrhea. Other strains with some levels of antibiotic resistance include Salmonella, Campylobacteria, and Streptococci.

Public Health Implications

One of the big concerns that health experts often raise about antibiotic resistance is the possibility of “superbugs,” or bacterial infections that can’t be treated with any existing medications. This could conceivably create a public health crisis, with patients contracting an illness that can’t be cured. With enough time, pharmaceutical researchers could probably create an even stronger drug to combat the new strains, but the biggest concerns are, firstly, that they wouldn’t be able to work fast enough to prevent widespread infection and death; and secondly, that the new medication would be so harsh that it would have a range of other undesirable side effects.

There isn’t a way to truly prevent antibiotic resistance. Most experts say that the process can be slowed with a more discretionary use of antibiotic drugs, though. If the drugs themselves are used sparingly, it will take the targeted bacteria that much longer to adapt and change.

Cattle have routinely been fed antibiotics for years.
Cattle have routinely been fed antibiotics for years.

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Discussion Comments


@anon195520: Diabetes, high blood pressure and heart disease just seem to go hand in hand, especially if the person isn't controlling one of these as well as he or she ought to. If your dad wasn't controlling his diabetes or high blood pressure very well, then a heart attack was probably bound to happen. The tumor on his prostate, in all likelihood, didn't have anything to do with his heart attack. It was probably the combination of the high blood pressure and diabetes.

You certainly have my condolences and sympathy. I am very sorry about what happened to your dad.


My dad died in June from cardiac arrest. He was diagnosed with high blood pressure in 1999, and diabetes in 2002, Now for the last year he was dying, and he was diagonised with prostate cancer and diabetes Type 1. The tumor on his prostate was large: 1.5. The greason result was 7. What was this? What might have triggered his death?


I try to buy food that was produced without the use of antibiotics, and I guess antibiotic resistance is a good reason to keep doing it.

Antibiotics are a wonderful thing. They have helped us so much. But there is such a thing as too much of a good thing. And it sounds like antibiotics are reaching that point. I think they should only be used when necessary.


It's kind of scary to think of a world filled with antibiotic resistant bacteria. I guess we just have to hope that there are people out there who are able to come up with new antibiotics as fast as the old ones stop working.

I hate to think about what the world would be like without antibiotics. Right now there is a bug going around my family, from one person to the next with amazing speed. I was just saying to my husband that we are so lucky that we don't live in the past, when fatal diseases did that and whole families got wiped out.

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