I am afraid you are on a sticky wicket. Hospitals are full of sick persons admitted for treatment. Several of them carry infection on or within themselves. Whilst hospital administrators, doctors, nurses and other staff take care to prevent one patient from infecting another, the proximity of patients (as in a general ward) will lead to some transfer of germs from one patient to another.
Hospitals cannot be sued for this hazard.
Even if the infection follows a procedure such as arteriography or surgery, your accusation may fall flat if the hospital shows that all due care was taken to prevent infection. This is because there are several factors conducive to the transmission, the immune response - or its lack - exhibited by the person getting the infection, being one.
Your complaint will succeed only if you can show that the infection acquired by you was a direct result of negligence by a staff member. One example is the use of a needle and syringe known to be unsterile to give you an injection. The onus of providing such proof is on you.