So, let's say we scale up a bacteria to the size of a human being. Let's make him a six-foot, two hundred pound specimen, which is pretty close to me. My volume, as a cylinder of 72" height with ellipsoidal cross section, is about 3.17 cubic feet. Times 15,000 is 47,550 cubic feet. Let's make a two story building, that's a footprint of 2,377 square feet, which is about your contemporary average house size. (Average US houses in 1973 first census data available - were 1,660 square feet.)
So, we've moved up in the world from a trailer to a well-to-do suburban ranch house.
Get out of my starter castle you bacterial bitch.
And take your dirty Pigpen menagerie cloud with you.