You might be surprised that your kitchen sink is probably the fixture in our homes with the most bacteria!
Most people expect the answer to be the toilet bowl. The reason why the kitchen sink has more bacteria is that more people make efforts to regularly disinfect their toilets. Far fewer people take the time to regularly disinfect their kitchen sink.
I'd recommend reading this article from WebMD which talks about some other top germ destinations in your home.
Here is a video in case you want to learn more about bacteria... I think I need to go disinfect my kitchen sink!
Hope this helps...