gram-negative

adjective

gram-neg·​a·​tive ˈgram-ˈne-gə-tiv How to pronounce gram-negative (audio)
: not holding the purple dye when stained by Gram's stain
used chiefly of bacteria

Examples of gram-negative 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.
Tate, who is vice president of sales for Mid-Florida Pathology, convinced doctors to administer gram-negative medications, which worked. Edward Lee, Baltimore Sun, 23 Jan. 2025 The team focused its search for a new drug on compounds that suppress the Lol system, which shuttles lipoproteins between the inner and outer membranes in gram-negative bacteria. Tribune News Service, The Mercury News, 20 June 2024 Bacteria populations in the average human gut are roughly split between gram-negative and gram-positive types, said Kristen Munoz, a former doctoral student at the University of Illinois who co-led the study. Corinne Purtill, Los Angeles Times, 12 June 2024 Encased in both an inner and outer membrane that antibiotics struggle to cross, gram-negative bacteria are resistant to most currently available therapies. Corinne Purtill, Los Angeles Times, 3 Jan. 2024 Shigella bacteria are gram-negative bacteria, shaped like rods, recognized worldwide as the most common cause of dysentery, a gastrointestinal illness resulting in severe diarrhea. CBS News, 1 Mar. 2023

Word History

First Known Use

1907, in the meaning defined above

Time Traveler
The first known use of gram-negative was in 1907

Dictionary Entries Near gram-negative

Cite this Entry

“Gram-negative.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/gram-negative. Accessed 30 Jan. 2025.

Medical Definition

gram-negative

adjective
gram-neg·​a·​tive ˈgram-ˈneg-ət-iv How to pronounce gram-negative (audio)
: not holding the purple dye when stained by Gram's stain
used chiefly of bacteria
Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!