The plumber was called in and removed the blockage and the restoration company has provided fans, dehumidifiers, and microbial compound to kill the bacteria associated with the overflowing fluids.My downstairs floor is laminate wood flooring.

It just seems like such a waste of space in the room, would only invite bacteria on the carpet, and is an unnecessary area for possible plumbing problems in the future.

Most wells will test positive for bacteria, my last property on private water contained ecoli and coliform (also in Ohio).

I told the tenant that I would need to call this property uninhabitable (since she had screamed at me about how the mold and bacteria from the sewage water can harm herself and her child) and asked her to find herself alternate accommodations.

As for the septic that could cause unique proportys in a rental, if your tennent doesnt know better they could really mess it up flushing things that dont degrade or kill the bacteria in the system by dumping household chemicals down the drain. 

There have been cases of people getting their brains eaten by bacteria from dirty neti pot water

I ALWAYS have separate pros inspect the roof, HVAC, structural (if something is seen that warrants it), sewer main (or, septic, including separate sewer scope for drainfield AND perk test), and water well (bacteria and pump flow, etc.), if not on public water. 

The contractor suggests duct cleaning that we'll do anyway, but I was wondering if anyone has had a similar issue like ours and could provide additional info on the questions below:- some additional info re reason of the smell (what kind of bacteria is it?)

Proper sanitation of surfaces ***Make sure to wear disposable gloves when cleaning***When you sanitize a surface to kill off dangerous germs and bacteria 1.

I use to work on bacteriophage (virus targeting on bacteria, benign to human) and have some knowledge on virus.