meth·​i·​cil·​lin | \ ˌme-thə-ˈsi-lən How to pronounce methicillin (audio) \

Definition of methicillin

: a semisynthetic penicillin C17H19N2O6NaS used especially in the form of its sodium salt against beta-lactamase-producing staphylococci

Examples of methicillin in a Sentence

Recent Examples on the Web

Increasingly, doctors need to administer intravenous antibiotics—as in Osbourne's case—to treat serious staph infections as more strains, like MRSA (methicillin-resistant Staphylococcus aureus), develop resistance to the usual treatment. Carolyn L. Todd, SELF, "Ozzy Osbourne Underwent Hand Surgery to Treat Multiple Staph Infections: ‘It Was Agony’," 23 Oct. 2018 A month later, her father contracted methicillin-resistant Staphylococcus aureus. Rachel Leingang, azcentral, "Former employee sues ASU, claiming violation of federal medical leave law," 19 June 2018 The bacteria involved are resistant to not only methicillin but also amoxicillin, penicillin and oxycillin. Cathie Anderson, sacbee, "Influenza B surging as overall flu cases fall — and it's deadlier in kids, experts say | The Sacramento Bee," 19 Mar. 2018 Medicare also examines rates of methicillin-resistant Staphylococcus aureus, or MRSA, and Clostridium difficile, known as C-diff. Jordan Rau, Washington Post, "Half Of Hospitals In Conn., Del. Hit By Medicare’s Safety Penalties," 5 Jan. 2018 In early tests in rats infected with methicillin-resistant Staphylococcus aureus (MRSA), the researchers found that the molecules were able to sterilize the infection area. Alexandra Sifferlin, Time, "A Potentially Powerful New Antibiotic Is Discovered in Dirt," 14 Feb. 2018 Health providers did manage to cut central line infections in half as planned, but the same goal for halving the number of methicillin-resistant staph infections, often called MRSA infections, only dropped by 36 percent. Paul Sisson,, "Report: Some hospital infection rates too high," 3 Feb. 2018 Doctors told the family that Harmon had developed pneumonia and methicillin-resistant Staphylococcus aureus (MRSA), an aggressive staph infection. Jason Duaine Hahn,, "Oregon Mom Dies Just Two Days After Being Diagnosed with the Flu: 'I'm at a Loss,' Says Boyfriend," 30 Jan. 2018 The spread of methicillin-resistant Staphylococcus aureus (MRSA) and other antibiotic-resistant germs has become a major public health issue. Washington Post, "Infection Lapses Rampant In Nursing Homes But Punishment Is Rare," 22 Dec. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'methicillin.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of methicillin

1961, in the meaning defined above

History and Etymology for methicillin

meth- + penicillin

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The first known use of methicillin was in 1961

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meth·​i·​cil·​lin | \ ˌmeth-ə-ˈsil-ən How to pronounce methicillin (audio) \

Medical Definition of methicillin

: a semisynthetic penicillin C17H19N2O6NaS that is especially effective against beta-lactamase producing staphylococci

Comments on methicillin

What made you want to look up methicillin? Please tell us where you read or heard it (including the quote, if possible).


an act or instance of returning to life

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