Here are two papers about infection control in hospitals.
The first is an impressive account of implementation. In a quasi-military setting (the Veterans Administration), a bundle of packages was mandated in all hospitals. Impressive falls in MRSA followed.The intervention was as follows:
"The bundle consisted of surveillance for nasal colonization with MRSA for all patients admitted to the hospital, all patients transferred from one unit to another within the hospital, and all patients discharged from the hospital; contact precautions for patients who were either colonized or infected with MRSA; hand hygiene; and a change in the institutional culture"
I particularly like the attention paid to institutional culture. Before-and-after comparisons are tricky because so much else can be going on, but in this case the extent of the drop and its timing are pretty convincing. Note also the careful attention to definitions of MRSA colonisation or infection, and to data capture.
The second study used a stronger design (a randomised controlled trial) but a weaker intervention - no signficant changes resulted.