Using MRSA as an example, everyone is (quite rightly!!!) concerned with hand washing and cross-infection control measures in hospitals.
However MRSA is NOT a 'big nasty bug that lives in dirty NHS hospitals' (not exclusively anyway!!)
Remember, firstly WHY MRSA is MRSA (many factors but probably mainly over use of antibiotics to placate an ignorant and difficult public who have demanded them inappropriately for many years) and secondly MRSA will typically only affect suscpetible individuals.
A good percentage of the population walk around everyday carrying MRSA (yes at work, at school, at home, in the pub., at the swimming baths etc..) with no adverse consequences, the problems arise when they transfer it to those that are suseptible.
Now I hope you can see where I'm going with this, who do you think these susceptible people are? Well sick people of course and you find sick people in HOSPITALS (BOTH private and NHS).