After monoassociation of Bifidobacterium longum with germ-free BALB/c mice (nu/+, heterozygous to nu gene), B. longum was recovered (10(2)-10(4) viable units per organ) from the mesenteric lymph nodes, liver and kidneys for 2 weeks post intragastric inoculation, but not after 4 weeks and later. Cess …