bifidobacterium
noun
bi·fi·do·bac·te·ri·um
ˌbī-fə-(ˌ)dō-ˌbak-ˈtir-ē-əm 
1
capitalized
: a genus (family Bifidobacteriaceae) of gram-positive, nonmotile, anaerobic bacteria that occur as invariably shaped, often branching rods, that are part of the normal intestinal and vaginal flora of humans, and that produce acetic and lactic acid by the fermentation of carbohydrates
This is particularly true of Lactobacillus and Bifidobacterium, two genera of lactic acid-producing bacteria long thought to be vital members of a healthy gut flora.—
Garry Hamilton, New Scientist
Garry Hamilton, New Scientist… cesarean section infants display reduced abundances and/or incidences of colonization by the genera Bacteroides and Bifidobacterium early in development relative to infants born by vaginal delivery.—Elizabeth K. Costello et al., Science
Elizabeth K. Costello et al., Science2
plural bifidobacteria
ˌbī-fə-(ˌ)dō-ˌbak-ˈtir-ē-ə
: any bacterium of the genus Bifidobacterium
: any bacterium of the genus Bifidobacterium
Look for a probiotic that has a blend of lactobacilli and bifidobacteria.—Kay Judge and Maxine Barish-Wreden, The Sacramento Bee
Kay Judge and Maxine Barish-Wreden, The Sacramento BeeAmong hospitalized infants, those given formula enriched with bifidobacteria (the bacteria found in breast milk) are less likely to develop infectious diarrhea.—Molly Caldwell Crosby, Newsweek
Molly Caldwell Crosby, NewsweekCite this Entry
“Bifidobacterium.” Merriam-Webster.com Medical Dictionary, Merriam-Webster, https://www.merriam-webster.com/medical/bifidobacterium. Accessed 4 Nov. 2025.
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