lactobacillus
noun
lac·to·ba·cil·lus
ˌlak-tō-bə-ˈsi-ləs 
: any of a genus (Lactobacillus) of bacteria that produce lactic acid
Examples of lactobacillus in a Sentence
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To keep things balanced, the formula also includes lactobacillus ferment, a postbiotic that supports a healthy skin microbiome—key for maintaining a strong barrier, especially if your skin tends to be reactive or sensitive.
—
Christa Joanna Lee, Allure, 3 July 2025
Identifying higher levels of healthy lactobacillus in the guts of people engaging in good anti-stress behaviors.
—John Werner, Forbes.com, 13 June 2025
The true star ingredient of this formula is lactobacillus—a probiotic extract that helps repair the microbiome to rapidly calm redness and irritation.
—Conçetta Ciarlo, Vogue, 13 June 2025
In healthy women without bacterial vaginosis, lactobacillus crispatus is the dominant bacteria and in those in a dysbiotic state there’s less lactobacillus crispatus and a more diverse microbiota, including bacteria like gardnerella vaginalis.
—Sara Novak, Discover Magazine, 12 June 2024
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Christa Joanna Lee, Allure, 3 July 2025
Identifying higher levels of healthy lactobacillus in the guts of people engaging in good anti-stress behaviors.
—John Werner, Forbes.com, 13 June 2025
The true star ingredient of this formula is lactobacillus—a probiotic extract that helps repair the microbiome to rapidly calm redness and irritation.
—Conçetta Ciarlo, Vogue, 13 June 2025
In healthy women without bacterial vaginosis, lactobacillus crispatus is the dominant bacteria and in those in a dysbiotic state there’s less lactobacillus crispatus and a more diverse microbiota, including bacteria like gardnerella vaginalis.
—Sara Novak, Discover Magazine, 12 June 2024
See All Example Sentences for lactobacillus
Cite this Entry
“Lactobacillus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lactobacillus. Accessed 31 Oct. 2025.
Copy CitationMedical Definition
lactobacillus
noun
lac·to·ba·cil·lus
ˌlak-tō-bə-ˈsil-əs
1
capitalized
: a genus of gram-positive nonmotile lactic-acid-forming bacteria of the family Lactobacillaceae including various commercially important lactic acid bacteria
2
plural lactobacilli
-ˌī also -ˌē
: any bacterium of the genus Lactobacillus
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