ABSTRACT
Antibiotics are natural products obtained from the growth of cultures of bacteria, molds, and soil actinomycetes. They are substances, which, in low concentrations, are destructive or inhibitory to microorganisms. The most famous of these is the drug penicillin produced by the mold growth, Penicillium notatum. All types of penicillin have the same basic structure but by substituting different radicals on the amino chain of the molecule, various types of penicillin may be produced.
