Why do different bacteria give us different sicknesses?

It mostly depends on where bacteria live on our body. If bacteria naturally live in our nose and throat, sometimes they can take advantage of us and cause infection like strep throat or sinusitis. If they live near our urinary system, at times they might cause a urinary tract infection. Sometimes bacteria have a special capsule or part that makes them more likely to cause infection. But for the most part, bacteria cause infection in the area where they naturally live, and different bacteria live on different parts of our bodies.