Benzylpenicillin of penicillin allergy. Use during pregnancy is generally safe. It is in the penicillin and β-lactam class of medications. Benzylpenicillin was discovered in 1929 by Alexander Fleming and came into commercial use in 1942. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world is about US$0.24–2.72 per day. In the United States a course of treatment costs $100–200. As an antibiotic, benzylpenicillin is noted to possess effectiveness mainly against Gram-positive organisms. Some Gram-negative organisms such as "Neisseria gonorrhoeae" and "Leptospira
History of penicillin Regional Research Laboratory (NRRL) in Peoria, Illinois, United States, developed methods for industrialized penicillin production and isolated higher-yielding strains of the "Penicillium" fungus. In December 1942, survivors of the Cocoanut Grove fire in Boston were the first burn patients to be successfully treated with penicillin. Simultaneous research by Jasper H. Kane and other Pfizer scientists in Brooklyn developed the practical, deep-tank fermentation method for production of large quantities of pharmaceutical-grade penicillin. Dorothy Hodgkin determined the correct chemical structure of penicillin using X-ray crystallography at Oxford in 1945. In Kundl, Tyrol, Austria, in 1952, Hans Margreiter and Ernst Brandl of Biochemie