ANTIBIOTICS : Introduction & Work

=>  What are ANTIBIOTICS?

Antibiotics are types of antimicrobial substance active against bacteria and are the most important type of antibacterial agent for fighting bacterial infections. Antibiotic medications are widely used in the treatment and prevention of such infections. They may either kill or inhibit the growth of bacteria. A limited number of antibiotics also possess antiprotozoal activity.
The word antibiotic means “against life.” Any drug that kills germs in our body is technically an antibiotic. But most people use the term when they’re talking about medicine that is meant to kill bacteria.
Antibiotics have been used since ancient times. Many civilizations used topical application of mouldy bread, with many references to its beneficial effects arising from ancient Egypt, China, Serbia, Greece and Rome. The first person to directly document the use of moulds to treat infections was John Parkinson (1567–1650). Antibiotics revolutionized medicine in the 20th century. Alexander Fleming (1881–1955) discovered modern day penicillin in 1928.
The discovery of the antibiotic penicillin in the 1920s made a big impact on human history. Not only did it lead to a cure for bacterial infections that were once deadly, but it also led a big interest in finding new antibiotics. Today many different types of antibiotics are available, and they fight infection in several ways.

=>  FAST FACTS On Antibiotics:-

·         Alexander Fleming discovered penicillin, the first natural antibiotic, in 1928.
·         Antibiotics cannot fight viral infections.
·         Fleming predicted the rise of antibiotic resistance.
·         Antibiotics either kill or slow the growth of bacteria.
·         Side effects can include diarrhea, an upset stomach, and nausea.

=>  How Do Antibiotics WORK?

Antibiotics aren’t the answer for every infection our child gets. In fact, there are 2 major types of germs that cause most infections, viruses and bacteria, and antibiotics are useful only against bacteria.
·         Bacteria are one-celled organisms that are just a few thousandths of a millimeter in size. They live on our skin, in our digestive system, and in our mouths and throats. In fact, there are one hundred thousand billion bacteria living and thriving on or inside of us. Although most are either harmless or actually serve a positive role in the body (eg, helping to break down the nutrients in our diet), some are dangerous and cause illnesses. They’re responsible for many childhood diseases, including most ear infections, strep throat, some sinus infections, and urinary tract infections.
·         Viruses are even smaller than bacteria. The poliovirus, for example, is only 16 millionths of a millimeter in diameter. Despite their size, viruses can cause mild and serious diseases when they enter healthy cells in the body. They’re responsible for the common cold, the flu, and most sore throats and coughs. They also cause smallpox, the measles, the mumps, hepatitis, and acquired immunodeficiency syndrome (AIDS). As powerful as antibiotics are when used in the right situations, they cannot kill viruses and do not work against viral infections. If they’re given to the child when she has a viral infection, they can not only cause side effects, but also add to the serious problem of antibiotic resistance. There are drugs called antivirals that have been developed to fight viruses.

=>  What Antibiotics CAN DO?

Different families of antibiotics have different ways of killing bacteria. Below are descriptions of a few types of antibiotics and their mechanisms of action.

• -  Beta-Lactam

Beta-lactam antibiotics kill bacteria that are surrounded by a cell wall. Bacteria build cell walls by linking molecules together—beta-lactams block this process. Without support from a cell wall, pressure inside the cell becomes too much and the membrane bursts. Examples of beta-lactams include penicillin and cephalosporin, which are used to treat many types of bacterial infections.

• -  Macrolides

Antibiotics in the macrolide group affect ribosomes, the cell’s protein-building machines. Ribosomes build proteins in both bacteria and human cells, but there are differences between bacterial and human ribosomes. Macrolides block only bacterial ribosomes and prevent them from building proteins. Since proteins do all the cell’s work, a bacterium that cannot build proteins cannot survive. Erythromycin, which is commonly used to treat respiratory tract and skin infections, is a macrolide.

• -  Quinolones

Quinolones include antibiotics like ciprofloxacin and levofloxacin, which are used to treat infections like bronchitis and pneumonia. When bacteria begin to copy their DNA, quinolones cause the strands to break and then prevent the breaks from being repaired. Without intact DNA, bacteria cannot live or reproduce.

• -  Antibiotics Harm Friendly Bacteria

When we take an antibiotic, it enters our bloodstream and travels through our body, killing bacteria but not human cells. There are few differences, however, between harmful and friendly bacteria. Antibiotics kill not only the bad bacteria making us sick, but also our resident friendly bacteria. Friendly bacteria help keep us healthy in many ways, so when antibiotics kill friendly bacteria, our health can suffer because we lose these benefits. Additionally, losing friendly bacteria can give other types of bacteria room to multiply, leading to opportunistic infection. Sometimes opportunistic infection happens when bacteria from the environment get into our body and overrun friendly bacteria damaged by an antibiotic. Other times opportunistic infection begins when antibiotics disturb the balance of our resident microbes, and normally friendly bacteria multiply too quickly and become harmful.