I. An Historical Overview of Antibiotics
Allow me to begin with an historical overview of antibiotics. The antibiotics field was initiated when Paul EHRLICH first coined the term ‘magic bullet’, or chemotherapy, to designate the use of antimicrobial compounds to treat microbial infections. In 1910, EHRLICH discovered the first antibiotic drug, Salvarsan, which was used against syphilis. EHRLICH was followed by Alexander FLEMING, who discovered penicillin by accident in 1928. Then, in the 1935, Gerhard DOMAGK discovered the sulfa drugs, thereby paving the way to the discovery of the anti-TB drug Isoniazid. Then, in 1939, René DUBOS became the first scientist to discover an antibiotic after purposely looking for it in soil microbes. DUBOS discovered Gramicidin, which is still used today to treat skin infections. Finally, in 1943, the first TB drug, Streptomycin, was discovered by Selman WAKSMAN and Albert SCHATZ. WAKSMAN was also the one who coined the term ‘antibiotics’. Thus, antibiotics have been used to treat bacterial infections since the 1940s. II. The Basic Characteristics of Antibiotics
Today, there are about 4 000 compounds with antibiotic properties. Antibiotics are used to treat and prevent infections, and to promote growth in animals. Antibiotics are derived from three sources: moulds or fungi; bacteria; or synthetic or semi-synthetic compounds. They can be used either internally or topically, and their function is to either inhibit the growth of pathogens or to kill them. Antibiotics can thus be divided into Bacteriostatic drugs, which merely inhibit the growth of the pathogen, and Bacteriocidal drugs, which actually kill the bacteria. However, the distinction is not absolute, and depends on the drug concentration, the bacterial species, and the phase of growth. Antibiotics are more effective against actively growing bacteria, than against non-growing persisters or spores. When two antibiotics are used in combination, the effect...
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