In 1928 Alexander Fleming discovered penicillin, the first antibiotic, by coincidence. The term “antibiotic” literally means “against life”. These chemical substances prevent bacteria from proliferating.
Against one bacterium
Some antibiotics are developed to fight only a limited number of different bacteria. These are called “small-spectrum antibiotics”. Your doctor will prescribe them when he knows exactly what kind of bacterium causes your disease. These antibiotics are the most appropriate treatment as they do not attack other, useful or harmless, bacteria.
Against several bacteria
Other antibiotics have a broad spectrum of activity. They act against several bacteria and are called “broad-spectrum antibiotics”. Sometimes, these drugs are needed because your doctor does not know exactly what kind of bacterium causes your disease or because there are several pathogens involved. The disadvantage is that they also tend to kill useful or harmless bacteria.