themusic's writeup above reminds me of the slogan on the sign above many of the sinks here in Concord Hospital (the Olympic Hospital, btw), Sydney -- "Hand washing sinks Staph", which means that even the most virulent and drug resistant bug, MRSA (Methicillin resistant Staph. aureus) will not be transmitted between patients if health staff, especially lazy doctors, wash their hands properly between seeing each patient.
Having said this, it is painfully obvious that most hand washing techniques are simply insufficient to kill enough bacteria to prevent cross contamination between patients. The best one can hope for in a big hospital is the reduction of risk. Really clean hands require scrubbing, not just hand washing. This takes too much time to be practical when going from one patient to the next.