polymyxin
noun
poly·myx·in
ˌpä-lē-ˈmik-sən 
: any of several toxic antibiotics obtained from a soil bacterium (Bacillus polymyxa) and active against gram-negative bacteria
Examples of polymyxin in a Sentence
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After 30 days of exposure, the bacteria could tolerate doses of polymyxin B that were 256 times higher than the original amount, but the SCUBs remained effective at the same dose.
—
Max G. Levy, Wired, 30 Nov. 2021
Instead, antibiotics commonly used in flu vaccine manufacturing include neomycin, kanamycin, polymyxin B and gentamicin.
—Anne P. Kim, The Conversation, 13 Nov. 2020
In a study published last month in The Lancet, the scientists describe the emergence of a new gene, MCR-1, that grants E. coli bacteria immunity to a class of antibiotics called colistin, also referred to as polymyxin.
—Nathaniel Scharping, Discover Magazine, 12 Dec. 2015
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Max G. Levy, Wired, 30 Nov. 2021
Instead, antibiotics commonly used in flu vaccine manufacturing include neomycin, kanamycin, polymyxin B and gentamicin.
—Anne P. Kim, The Conversation, 13 Nov. 2020
In a study published last month in The Lancet, the scientists describe the emergence of a new gene, MCR-1, that grants E. coli bacteria immunity to a class of antibiotics called colistin, also referred to as polymyxin.
—Nathaniel Scharping, Discover Magazine, 12 Dec. 2015
Cite this Entry
“Polymyxin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/polymyxin. Accessed 31 Oct. 2025.
Copy CitationMedical Definition
polymyxin
noun
poly·myx·in
ˌpäl-i-ˈmik-sən
: any of several toxic antibiotics obtained from a soil bacterium of the genus Bacillus (B. polymyxa) and active against gram-negative bacteria
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