Antibiotics are a type of drugs or medicines that hinder the growth of bacteria. Generally, they kill the microorganisms and also cure bacterial infections. Any drug that kills any microorganism or germ is known as antibiotics. The first-ever antibiotics discovered was Penicillin. So far, over 4500 different antibiotics have been recorded, but only some 100 have been widely used to treat human, animal and plant diseases. The genus Streptomyces is the source of more than one half of the known antibiotics, the other being derived from Micromonospora, Actinoplanes Nocardia, Actinomadura, Bacillus, and few other microbes.