|any of a group of antibiotics with powerful bactericidal action, used to treat many types of infections, including pneumonia, gonorrhoea, and infections caused by streptococci and staphylococci: originally obtained from the fungus Penicillium, esp P. notatum. Formula: R-C9H11N2O4S where R is one of several side chains|
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penicillin pen·i·cil·lin (pěn'ĭ-sĭl'ĭn)
Any of a group of broad-spectrum antibiotic drugs obtained from penicillium molds or produced synthetically, most active against gram-positive bacteria and used in the treatment of various infections and diseases.
|penicillin (pěn'ĭ-sĭl'ĭn) Pronunciation Key
An antibiotic drug obtained from molds of the genus Penicillium and used to treat or prevent various infections caused by gram-positive bacteria such as streptococcus. Penicillin was the first of a class of antibiotics (whose names end in -icillin) that are derived from it and are active against a broader spectrum of bacteria. See Note at Alexander Fleming.
An antibiotic that is used to treat infections caused by some kinds of bacteria. Penicillin, which is derived from a common kind of mold that grows on bread and fruit, was the first antibiotic discovered and put into widespread use.
Note: Penicillin was first widely used during World War II.