The OCD notion of cleanliness doesn't always have really anything to do with any real germs or other pathogens. "Dirtiness" is more an abstract concept that varies and develops over time.
I think, in this case, it's the fear of the known that is the problem. "Dirty" is the concept used to describe all the reasons to clean stuff. But, real-world issues like MRSA are scary and the root of this slippery slope. Combined with the fact that my spouse works in a highly contagious environment doesn't help.
