Antibiotic

An antibiotic is a special kind of medicine used to treat infections caused by bacteria. These tiny living things can make people very sick, and antibiotics help stop them from growing or even kill them. Doctors use antibiotics to fight many kinds of bacterial infections, whether someone feels a little unwell or very ill. They also help prevent infections from getting worse or spreading.

Antibiotics work in different ways, but their main job is to either stop bacteria from growing or destroy them completely. Some antibiotics can also fight certain other tiny organisms called protozoa, but they do not work against viruses like those that cause the common cold or influenza. For viral infections, doctors use a different kind of medicine called antiviral drugs. Similarly, antibiotics are not helpful against fungi; for those, special antifungal drugs are used instead.

The word “antibiotic” comes from ancient Greek, meaning “against life.” True antibiotics, like penicillin, are usually made naturally by one microorganism that fights off another. There are also man-made medicines called antibacterials, such as sulfonamides and antiseptics, which work in a similar way but are not natural antibiotics. Both kinds are very important in medicine and sometimes even in livestock feed to keep animals healthy.

Early history

People first used antibiotics a long time ago, even before modern science. In places like ancient Sudan, people drank special liquids that helped fight germs. Scientists found proof in Nubian bones that they used a strong medicine called tetracycline. They made it from grains mixed with a special kind of bacteria named Streptomyces.

Other old cultures, such as Egypt, China, Serbia, Greece, and Rome, also used moldy bread to help with sickness. A big change came in 1928 when scientist Alexander Fleming found a powerful medicine called penicillin. This became very useful, especially when many people needed medicine during tough times. But it’s important to use antibiotics the right way, because some germs can learn to fight back against them.

Etymology

The word "antibiotic" has two parts: anti, meaning "against", and biotic, related to life. A scientist named Selman Waksman first used it in 1942. He used it to describe things that stop tiny living things called bacteria from growing.

Before that, in 1877, scientists Louis Pasteur and Robert Koch found that some bacteria could stop others. Later, Selman Waksman named these special substances "antibiotics" in 1947. Today, "antibiotic" means any medicine that can stop or kill bacteria, no matter where it comes from.

Usage

Antibiotics are important medicines used to treat or prevent infections caused by bacteria. They help when a doctor thinks an infection might be making someone sick but isn’t sure which germ is causing it. In these cases, doctors might use a broad-spectrum antibiotic until they get test results.

When doctors know which germ is causing an infection, they can choose a more specific antibiotic. This helps make treatment safer and less likely to lead to antibiotic resistance. Antibiotics are also used to prevent infections in people who are more likely to get sick, such as those with weakened immune systems, cancer patients, or people having surgery. They can be taken in different ways, such as pills, liquids, or even drops for the eyes or ears, depending on where the infection is.

Side effects

Antibiotics are usually safe, but sometimes they can cause problems that range from small to big. Common issues include diarrhea because of changes in the tiny living things in your tummy and yeast infections, which can happen when the balance of bacteria in your body changes.

Some antibiotics might also cause allergic reactions or interact with other medicines. Taking probiotics can help stop some kinds of diarrhea caused by antibiotics.

Interactions

Antibiotics can sometimes change how other medicines work. Most antibiotics do not stop birth control pills from working. But if you miss a pill, vomit, or have diarrhea, the pills might not work as well. Women with irregular periods should use another way to prevent pregnancy while taking antibiotics and for a little while after.

Drinking alcohol with some antibiotics can make you feel very sick. Antibiotics like metronidazole and erythromycin are examples. It’s best to ask a healthcare provider if it’s okay to drink alcohol while taking any antibiotic.

Pharmacodynamics

Main article: Antimicrobial pharmacodynamics

Antibiotics fight infections in different ways. Some kill bacteria, while others stop them from growing. Doctors test antibiotics in a lab before using them to make sure they work.

Using more than one antibiotic at the same time, called combination therapy, can help treat tough infections. This can make the antibiotics work better and prevent bacteria from becoming resistant. Doctors choose combinations carefully to make sure they work well together.

Classes

Main article: List of antibiotics

Antibiotics are grouped by how they work, their chemical makeup, or the bacteria they affect. Some antibiotics target the bacterial cell wall, like penicillins and cephalosporins. Others affect the cell membrane, such as polymyxins. These can kill bacteria. Another group stops bacteria from growing by interfering with their protein production, including macrolides and tetracyclines. Some antibiotics work against only certain bacteria, while others, called broad-spectrum antibiotics, work against many types. New classes of antibiotics have been developed to fight tough infections.

Production

Main article: Production of antibiotics

Modern antibiotics are made by changing natural compounds. For example, beta-lactam antibiotics like penicillins come from fungi called Penicillium. Other antibiotics, such as aminoglycosides, come from living organisms. Scientists have worked to make these medicines in large amounts since the 1930s. They use special processes to grow the compounds with oxygen.

Resistance

Main article: Antimicrobial resistance

Antimicrobial resistance (AMR or AR) is when bacteria change so they can survive antibiotics. This happens when antibiotics are used too much or not the right way. Because of this, many bacteria are harder to treat, and this is a big problem for health everywhere.

When people take antibiotics, some bacteria can survive because they change to protect themselves. Over time, these bacteria can grow stronger. This makes the antibiotics less effective. For example, some bacteria can now resist drugs that used to work well. This change can happen in different ways, like sharing tiny pieces of DNA. Because of these changes, diseases that were easy to treat are becoming harder to cure.

History

Main article: Timeline of antibiotics

Before the early 20th century, people used mixtures from plants and molds to try to treat infections. Ancient cultures like the ancient Egyptians and ancient Greeks used special molds and plants for this purpose.

The modern use of antibiotics began with the discovery of synthetic antibiotics from dyes. In the late 1880s, Paul Ehrlich in Germany suggested that certain dyes could target and stop bacteria without harming human cells. In 1907, he and his team discovered the first synthetic antibacterial drug called salvarsan, which was used to treat syphilis.

Later, in the 1920s and 1930s, researchers discovered natural antibiotics. In 1928, Alexander Fleming noticed that a mold called Penicillium rubens could stop bacteria. This led to the development of penicillin, which became widely used after World War II. These discoveries marked the start of modern antibiotic medicine.

Antibiotic pipeline

The World Health Organization and the Infectious Disease Society of America say that we need more new antibiotics. This is because bacteria are getting better at resisting the ones we have. Only a few new antibiotics have been approved recently, and they do not work against all kinds of resistant bacteria.

Scientists are finding new ways to fight bacterial infections. They are looking at natural products from plants and animals, special antibodies, and tiny viruses called bacteriophages that can target specific bacteria. These new methods could help treat infections that current antibiotics cannot fight.