As we said above, grouting and silicone are the culprits here. Because they're permeable materials they can retain water, creating favourable conditions for mould.
So if you want to remove bathroom mould once and for all, remove all grouting and silicone from your bathroom.
How? By replacing your bath or shower with a shower cubicle.
A self-contained shower cubicle requires no tiling, which means no grouting, no silicone, and no mould.
They can be assembled in the space of a day, and they're designed to fill the exact space where your shower used to be. And as this picture proves, they can be every bit as stylish as an ordinary shower enclosure: