Penicillium was discovered in 1809 by Johann Heinrich Friedrich Link. Today it has been transformed into penicillin. Penicillin, an antibiotic, can prevent bacterial infections. It is also present in foods. It is invaluable in today's economy and practical use. Thanks to this, millions of lives have been saved. Along with the invention of anesthesia, the invention of antibiotics is considered one of the greatest gifts of medicine to the world. In 1927, Alexander Fleming studied the properties of staphylococci, a genus of Gram-positive bacteria. After leaving a staph sample alone for a few months, he noticed that the culture was covered in a fungus. However, neighboring staphylococci were completely eliminated, while more distant cultures were less affected. By taking the fungus and growing it in a pure culture, he produced a substance to destroy disease-causing bacteria. Further tests proved that it cured diseases such as pneumonia, scarlet fever and other gram-positive diseases. However, the Gram-negative bacteria tested and causing illnesses such as typhoid fever were not affected by the antibiotic. He continued his research, but was unable to quickly reproduce the quantity of mold. In 1939, Nobel Prize winner Dr. Howard Florey and three colleagues at Oxford University began extensive research and were able to prove penicillin's ability to kill infectious bacteria. The ongoing war with Germany reduced resources and British scientists turned to the United States for help, as they did not have enough results to produce good quality penicillin. In the United States, scientists were already working on fermentation methods to increase the growth rate of mushroom cultures......from the medium of paper cultures......l. On July 9, 1941, Howard Florey and Norman Heatley, scientists from the University of Oxford, arrived in the United States with a small package containing a small amount of penicillin to begin their work. There was a narrow range of treatable diseases and therefore, instead of trial and error in the use of antibiotics, broad spectrum antibiotics were created. Broad-spectrum antibiotics are a cocktail of antibiotics capable of simultaneously treating a wide range of diseases - Gram-positive bacteria. The first breakthrough was ampicillin, which demonstrated a broader spectrum of activity than any other penicillin. Continued development has manifested itself with new penicillins: flucloxacillin, methicillin and dicloxacillin. Although they treated most basic Gram-positive bacteria, they were unable to treat MRSA (Methicillin-resistant Staphylococcus aureus) that resulted from methicillin administration..