plural E. coli
: an enterobacterium (Escherichia coli) that is used in public health as an indicator of fecal pollution (as of water or food) and in medicine and genetics as a research organism and that occurs in various strains that may live as harmless inhabitants of the human lower intestine or may produce a toxin causing intestinal illness see enterobacterium illustration

Examples of E. coli in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Axford said, according to Arizona Department of Environmental Quality guidelines, water is considered unsafe if a single sample exceeds 235 colony-forming units of E. coli per 100 milliliters of water or if the average of recent results exceeds 125 colony-forming units. Tiffany Acosta, AZCentral.com, 4 July 2025 For instance, just like ground beef, raw shrimp can contain bacteria like E. coli. Ashia Aubourg, SELF, 4 July 2025 Local health departments across Milwaukee routinely test nearshore water to make sure levels of E. coli bacteria don't reach unsafe levels. Maia Pandey, jsonline.com, 3 July 2025 To be considered safe for swimming, the E. coli counts must be below 300 per 100 milliliters. Jalen Williams, Freep.com, 3 July 2025 See All Example Sentences for E. coli

Word History

First Known Use

1925, in the meaning defined above

Time Traveler
The first known use of E. coli was in 1925

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Cite this Entry

“E. coli.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/E.%20coli. Accessed 13 Jul. 2025.

Kids Definition

E. coli

noun
plural E. coli
: a bacterium in the shape of a short rod that may cause intestinal illness
Etymology

short for Escherichia coli, the taxonomic name in biology

Medical Definition

E. coli

noun
ˌē-ˈkō-ˌlī
plural E. coli also E. colis
: a straight rod-shaped gram-negative bacterium (Escherichia coli of the family Enterobacteriaceae) that is used in public health as an indicator of fecal pollution (as of water or food) and in medicine and genetics as a research organism and that occurs in various strains that may live as harmless inhabitants of the human lower intestine or may produce a toxin causing intestinal illness marked especially by diarrhea
one million acid-resistant E. coli per gram of fecesJohn Schwartz
this E. coli can survive … longer than all the other E. colisEd Geldreich
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