Understanding Antibiotics (Part 1)

Antibiotics are an important type of modern medicine. But they are not just like any other. Most medications modify the function of our body to control or cure a symptom or a disease. However, antibiotics are special, they do not have a direct effect on our body. Antibiotics act on the microorganisms (bacteria) present in our body, to suppress or kill them. And, we have a lot of microbes in the body.

Wait… do we really have microbes in our body?

Of course, yes. Whether we like it or not, our body is home to trillions (yes, that’s right, trillions) of microbes, including bacteria, viruses, fungi, and other tiny organisms. These microbes are present in different parts such as skin, nose, mouth, intestines and vagina and therefore stay in different communities. The entire population of such microbes in our body is called microbiome.

There are approximately 100 trillion cells in a human body, and only about 10 trillion of that are real “human” cells. The other 90 trillion are microorganisms!

Why do we have them? Don’t they hurt us?

Microbes are the oldest form of life on earth, they are around for more the 3 billion years. For the last 2-3 million years, they are co-existing with humans. We have a very complex relationship with microbes.

We need them. These microbes in our body play an important role in maintaining our health. This may be difficult to believe; because we learn only about the harmful bacteria in our schools and colleges.

All bacteria are not bad, most of them are neutral and some even beneficial. Our microbiome is essential for our immunity and it influences our metabolism. Some microbes even protect us from the harmful effects of bacteria that may invade our body from outside.

Then, why do we need antibiotics?

Sometimes, bacteria may cause disease. Usually, bacteria which are not present in our body enter and start multiplying rapidly. They may produce poisonous substances (toxins). When our body’s defence forces (immunity) recognize these harmful outsiders, they start a fight. Note that our immunity is usually intelligent enough to distinguish between harmful and helpful microbes.

Some bacteria are easy to defeat, and others very difficult. Our defence forces have various mechanisms to cordon off and kill these harmful microbes. During this process, we develop various symptoms, including fever. Fever is actually a defence mechanism as bacteria cannot multiply easily at slightly higher temperatures.

When we have an infection with harmful bacteria, and our body’s immunity is unable to successfully fight that infection, we need some additional weapons. Without those weapons, the disease may take a long time to recover and may even result in death.

Antibiotics are that weapon. They help in preventing the multiplication of bacteria and even kill them. They usually do not harm the real “human” cells. Antibiotics are saving human lives for the last 90 years. They have revolutionized modern healthcare after the discovery of the first antibiotic, penicillin, in 1928.

That’s great! Can I take antibiotics frequently to eliminate harmful bacteria?

Hold on! Though antibiotics do not usually harm the human cells, some antibiotics may produce side effects. Some side effects are due to the uncommon harm produced to human cells.

More importantly, antibiotics often destroy the “helpful” bacteria present in our body too (similar to collateral damage in human wars). When antibiotics kill the helpful bacteria, other harmful bacteria may find it easy to multiply and cause trouble.

Excessive use of antibiotics, obsession with cleanliness, modern trend of processed food, etc., are disrupting the delicate balance of microbes in the human body. This imbalance is perhaps, at least partly, responsible for the increase in disorders like asthma, allergies, diabetes, obesity, autoimmune diseases, and some cancers.

So, we need to be careful about indiscriminate and thoughtless antibiotic use.

Okay. Do antibiotics help in viral infections?

No. Antibiotics are not useful in treating viral infections! Antiviral medicines may be useful in some viral infections.

By using antibiotics for non-bacterial infections, we just expose the helpful bacteria in our body to these antibiotics. That in turn, unnecessarily, has other harmful effects.

So, it appears quite simple. Use antibiotics in bacterial infections…

Not simple! In the second part of this article, you’ll learn about the complexities of antibiotic use.

Antibiotics are a big deal. We are yet to discuss a “critical concept” of antibiotic use. You can read that in the second part of this article.

PS: Never pressure your doctor to prescribe antibiotics. Doctors are good judges of the need for an antibiotic based on your symptoms and tests. You can discuss the pros and cons of using an antibiotic with your doctor.

This article on “doctor-patient relationship” may be useful.

Shashikiran Umakanth Professor & Head, Department of Medicine

Dr Shashikiran Umakanth (MBBS, MD, FRCP Edin.) is Professor & Head of Internal Medicine at Dr TMA Pai Hospital, Udupi, Manipal Academy of Higher Education, India. He shares his insights on Medicine, Health and Life here.

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