Anti Microbial Drugs

Antibiotics, also called antibacterials, are a type of antimicrobial drug used in the treatment and prevention of bacterial infections.They may either kill or inhibit the growth of bacteria. A limited number of antibiotics also possess antiprotozoal activity. Antibiotics are not effective against viruses such as the common cold or influenza; drugs which inhibit viruses are termed antiviral drugs .

Sometimes the term antibiotic is used to refer to any substance used against microbes, Some sources distinguish between antibacterial and antibiotic; antibacterials are used in soaps and disinfectants, while antibiotics are used as medicine.

Antibiotics revolutionized medicine in the 20th century with vaccination, antibiotics have led to the near eradication of diseases such as tuberculosis in the developed world. However, their effectiveness and easy access have also led to their overuse, prompting bacteria to develop resistance.This has led to widespread problems, so much as to prompt the World Health Organization to classify antimicrobial resistance as a “serious threat is no longer a prediction for the future, it is happening right now in every region of the world and has the potential to affect anyone, of any age, in any country”.

The first antibiotic used by humans was penicillin, and it was discovered quite by accident. A bacteriologist named Alexander Fleming had been studying bacteria in Petri dishes. He left for vacation and did what many of us do in our own homes: left his used dishes sitting in the sink. Most of the Petri dishes were stacked in a tub of Lysol disinfectant to be cleaned later, but a few remained above the liquid.


When Fleming returned from vacation, the Petri dishes of bacteria were, of course, still piled in the sink. As he trudged over to begin the task of cleaning, he noticed something unusual. Mold had grown in some of the Petri dishes that had not been submerged in Lysol. In those dishes with mold, the bacteria was dying. It was clear that this mold, which was found to be the fungus Penicillium, inhibited and killed the bacteria. This would prove to be one of the most crucial breakthroughs of modern medicine.

How Do Antibiotics Works

An, antibiotics are medicines created to fight infection caused by bacteria. The word antibiotic literally means ‘against life.’ The goal is to kill or stop growth of these tiny infection-causing organisms, known as pathogens.Certain fungi are active in fighting infection. But there is another type of microbe that is commonly utilized in antibiotics, and it just so happens that often times, the component in an antibiotic that straps on its boxing gloves to fight off infection is actually another type of bacteria. This type of bacteria is usually found in soil, and examples include Streptomyces and Bacillus Antibiotics are designed to target the pathogens that are making us sick, killing them or stopping their growth. It is microbe against microbe, a battle to the death. But, how do the active components of antibiotics know which cells in our body to attack? In other words, how do they tell bacterial cells and human cells apart? Well, there are many different types of antibiotics, and they attack different kinds of cells in different ways.

Types of Antibiotics

A great deal of scientific research has brought about many different types of antibiotics. They often stem from just a few different drugs and are classified based on how they act on pathogens.

One class of antibiotics called beta-lactam zeroes in on a structure unique to bacterial cells. Their main tactic is to target the cell wall, which holds the cell together. Just like a water balloon would certainly break apart if part of the balloon were missing, the same goes for the bacterial cell. As the bacteria builds its cell wall, the components in the antibiotic step in to disrupt this process. Unable to stay intact, the infectious bacteria bursts. Penicillin is an example of an antibiotic that works in this fashion.

Another class of antibiotics called macrolides work by stopping the synthesis of protein by the bacteria. Every cell needs proteins to do work. In this case, the macrolides make it impossible for the proteins in the bacteria to be created. It’s like disabling part of the machinery that helps the bacteria work. Without the protein, the bacteria dies.

Still another type of antibiotics called quinolones work by messing up the process of DNA replication in bacteria. Bacteria colonies reproduce and grow by first replicating their genetic information, or DNA. When the bacterial cells attempt to replicate and make a new strand of DNA, quinolones work by breaking the DNA strands. It’s like someone knitting the first strand of a scarf, and someone else snipping it before it’s finished. Without intact DNA, the bacteria cannot successfully reproduce, and thus, the colony is extinguished.

One more interesting note about antibiotics. You may already know that they are not prescribed for viruses, such as the flu or common cold. But why is this? Viruses are fascinating organisms. What distinguishes them from other microorganisms is the fact that they are not technically alive. You can liken a virus to a zombie. It is essentially a shell that acts like a living creature, but it is not made of cells and has no metabolism. Therefore, there is no way f

By : – Dr. Rashmi Dhingra


Uttaranchal (P.G.) College of Biomedical Sciences and Hospital,