Acinetobacter calcoaceticus colonization was observed in the gastroint
estinal tracts of C.-B17-scid/scid (SCID) mice, while it was not obser
ved in C.B17-scid/+ and C.B17-+/+ mice with normal immunity housed und
er the same conditions. A. calcoaceticus and other viable enteric bact
eria were not isolated from any organs other than gastrointestinal tra
ct in SCID mice. The mice colonized with this organism were apparently
healthy and no significant visceral lesion was observed.