It has been proposed that the microbial flora of mammals would simplify to a few microbial species if the host animal was confined to a 'locked' environment and provided with sterile food, water, and air. This paper updates information on the microbial profile (feces, nose and throat) of purebred beagles housed in the above-mentioned conditions through a 30-month study period and demonstrates that no drastic decrease or simplification of the microbial profile occurred in isolated or control dogs.