AOB derive their energy solely from consuming the ammonia and urea found in sweat. To maximize ammonia utilization, Nitrosomonas produce unique enzymes on elaborately folded cell membranes. These membranes are intricately folded so that they can increase the surface area for ammonia-oxidation. This means that they are able to boost both their ammonia-oxidizing capacity and their energy output.
However, this elaborate membrane architecture also renders Nitrosomonas (and other AOB) particularly sensitive to membrane-disrupting chemicals, such as anionic surfactants found in modern soaps and detergents.
Before the advent of anionic surfactants, Nitrosomonas would have colonized our skin, our sweat glands in particular, constantly secreting low amounts of NO. Due to their particular sensitivity to detergents, however, they have been eradicated from our skin microbiome.