my·​co·​bac·​te·​ri·​um ˌmī-kō-bak-ˈtir-ē-əm How to pronounce mycobacterium (audio)
: any of a genus (Mycobacterium) of nonmotile aerobic acid-fast bacteria that include numerous saprophytes and the pathogens causing tuberculosis and leprosy
mycobacterial adjective

Examples of mycobacterium in a Sentence

Recent Examples on the Web After stem cell treatments abroad, three Americans became infected by mycobacterium abscessus, a distant relative of the bacteria that cause tuberculosis and leprosy. Eduardo Cuevas, USA TODAY, 9 May 2024 Three months later, in October 2023, the victim was diagnosed with a mycobacterium abscessus infection. Charna Flam, Peoplemag, 3 May 2024 Caused by bacteria mycobacterium tuberculosis, tuberculosis disease is spread through the air. Rong-Gong Lin Ii, Los Angeles Times, 25 Mar. 2024 There is a bacterium, a distant cousin of tuberculosis, called mycobacterium avium complex (MAC), which can cause coughing, shortness of breath and phlegm production. Lisa Sanders, M.d., New York Times, 6 Apr. 2023 Scientists took a closer look at the growth in the lab and discovered that the child had a rare infection with Mycobacterium marinum, a non-tuberculous mycobacterium that more commonly causes a tuberculosis-like illness in fish. Jen Christensen, CNN, 31 Mar. 2023 Probiotics have generally been regarded as safe, and most trials have confirmed this, but there is not long-term data on using probiotics for an extended period of time, such as the one or two years that people with mycobacterium avium complex typically are treated with antibiotics. Dr. Keith Roach, oregonlive, 25 Apr. 2022 Densely packed urban settings, a lack of ventilation, smog, and squalor proved to be an ideal smorgasbord for history’s deadliest mycobacterium. Natalie Shure, The New Republic, 20 Dec. 2021 Serious pathogens commonly found in plumbing include mycobacterium avium complex (MAC), which can lead to turberculois, and pseudomonas aeruginosa, which causes a wide variety of diseases including respiratory and gastrointestinal infections. Elena Bruess, San Antonio Express-News, 25 June 2021

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'mycobacterium.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


New Latin

First Known Use

1909, in the meaning defined above

Time Traveler
The first known use of mycobacterium was in 1909

Dictionary Entries Near mycobacterium

Cite this Entry

“Mycobacterium.” Dictionary, Merriam-Webster, Accessed 21 Jun. 2024.

Medical Definition


my·​co·​bac·​te·​ri·​um -ˈtir-ē-əm How to pronounce mycobacterium (audio)
capitalized : a genus of nonmotile acid-fast aerobic bacteria of the family Mycobacteriaceae that are usually slender and difficult to stain and that include the causative agents of tuberculosis (M. tuberculosis) and leprosy (M. leprae) as well as numerous purely saprophytic forms
plural mycobacteria -ē-ə How to pronounce mycobacterium (audio) : any bacterium of the genus Mycobacterium or a closely related genus
mycobacterial adjective

More from Merriam-Webster on mycobacterium

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