Many products list only the genus and species, but different strains provide different benefits (more on that later).
The most common probiotic bacteria come from two genus groups: Lactobacillus or Bifidobacterium, although there are many others.
(plural genera), 1550s as a term of logic, "kind or class of things" (biological sense dates from c.1600), from Latin genus (genitive generis) "race, stock, kind; family, birth, descent, origin," cognate with Greek genos "race, kind," and gonos "birth, offspring, stock," from PIE root *gen(e)- "produce, beget, be born" (cf. Sanskrit janati "begets, bears," janah "race," janman- "birth, origin," jatah "born;" Avestan zizanenti "they bear;" Greek gignesthai "to become, happen;" Latin gignere "to beget," gnasci "to be born," genius "procreative divinity, inborn tutelary spirit, innate quality," ingenium "inborn character," germen "shoot, bud, embryo, germ;" Lithuanian gentis "kinsmen;" Gothic kuni "race;" Old English cennan "beget, create;" Old High German kind "child;" Old Irish ro-genar "I was born;" Welsh geni "to be born;" Armenian chanim "I bear, I am born").
genus ge·nus (jē'nəs)
n. pl. gen·er·a (jěn'ər-ə)
A taxonomic category ranking below a family and above a species and generally consisting of a group of species exhibiting similar characteristics.
Plural genera (jěn'ər-ə)
A group of organisms ranking above a species and below a family. The names of genera, like those of species, are written in italics. For example, Periplaneta is the genus of the American cockroach, and comes from the Greek for "wandering about." See Table at taxonomy.