AntibioticsAn antibiotic is defined as a medicine produced by certain microbes. Most doctors use antibiotics to help fight germs in a patient. Antibiotics are obtained from plants, fungi, air, water, soil and just about everything else on earth. Antibiotics kill and attack germs or viruses in the body, but generally do not harm human cells. Antibiotics are used to treat many types of illnesses, such as tuberculosis, syphilis, and several types of infections. People have used antibiotics for over 2,500 years. They used molds to help cure certain skin infections and rashes. It was in the late 1800s that the true study of medicine began. Louis Pasteur discovered that bacteria caused disease and disproved the theory of spontaneous generation. After him, there was Robert Koch, who developed a method for isolating and growing bacteria. Scientists have tried to develop drugs that can kill microbes, but they have proven either dangerous or ineffective. In 1928, Alexander Fleming made a discovery. He detected that a substance he called “penicillin” was destroying the bacteria. Then, in the late 1930s, two British scientists invented a method for extracting penicillin from mold. This was the beginning of the development of new drugs to treat diseases and bacteria. Over the years, thousands of antibiotic substances have been discovered in nature as well as chemically produced, but few are safe and useful. However, those that are safe and effective have saved many lives and helped extend life expectancy. Currently, more than 70 different types of antibiotics are in use. Most antibiotics are used to treat infections, some against fungi and protozoa, but antibiotics are generally not effective against viruses. So they developed other methods such as vaccines against viruses. Antibiotics work in three ways: they can prevent cell wall growth; second, obstruct the cell membrane; or three disrupt chemical processes. When the antibiotic prevents the cell wall from forming, the antitoxin surrounds the bacteria's membrane and then forms a rigid wall that prevents the cell wall from opening, which would produce another cell. Human cells are not damaged because human cells do not have a cell wall. If the antibiotic obstructs the cell membrane, which controls the flow of elements into and out of the cell, then essential food can leak out of the cell. the substance could enter the cell, killing it. Human cells are not affected by this method because the antitoxin only affects microbial cells. If the antitoxin disrupts the chemical process, the microbe cannot