Advice on how to deal with dirty dishes

I recently moved into an apartment for the first time and I love my roommates. The only thing is that they leave their dishes soaking in the sink for over a week. One of them will clean all their dishes after a few days but the others won’t. There has been a layer of dirty dishes on the bottom of the sink with food still on them and it’s starting to smell. I think it may also be the cause of all the gnats in the apartment. I would just clean the dishes myself but I have tics which get triggered when I feel certain textures (such as the grime on a dish that’s been soaking) which is why I put my dishes away in the dishwasher immediately. I want to bring this up with my roommates but I don’t know how to and I don’t want to come across as annoying or rude. Any advice?