Antibiotics are widely used in the chemotherapy of microbial infections. The first antibiotic, penicillin , was discovered by Alexander Fleming in 1928 and developed for clinical use by florey . Streptomycin was developed by waksman in 1944, and was later followed by tetracyclines, cephalosporins, and other compounds.
Antibiotics differ from each other in their chemical structures and mode of action.
Like other chemotherapeutic agents, antibiotics may be harmful to the host as well as killing the target microorganism. In addition, some patients develop an allergy which, in the case of penicillin, may be dangerous. The most serious problem is that the organism may become resistant to the antibiotic, making treatment ineffective. Despite their dangers and disadvantages, antibiotics remain powerful tools in human and veterinary medicine, and their use has contributed greatly to the dramatic fall in the death-rate from communicable diseases over the last 50 years. The Penguin Dictionary of Psychology 2.