removing bacteria from bathroom and toilet
1/2 cup laundry bleach (5-6% sodium hypochlorite) in 1 gallon of water kills darn near everything. (31 ml/l if you are metric.) If the bleach is more concentrated, use less of it.

Please don't be an idiot and add ammonia, which will result in "everything" including "you" as it reacts to release poison gasses. This information is widely publicized but people seem to keep doing it anyway, thus the warning repeated here. Stick to bleach and water, only. Turn on the ventilation fan or open the window, apply, let it sit for several (5-6) minutes, rinse with plain water.

If bacteria are not the actual cause of your issues this won't help, but it will certainly take care of any bacteria on the surfaces.