Recent research suggests that brass door handles should be used because they are associated with lower rates of hospital-acquired infections such as MRSA and Clostridium difficile. Stainless steel, alloy and plastic surfaces which are now widely used in public buildings have been shown to allow bacteria to survive and spread.  Copper and brass, however, can kill the bacteria and also destroy the DNA that gives the bacteria resistance to antibiotics. 

Prof. Bill Keevil, head of the microbiology group at Southampton University, has said that using copper, and alloys made from the metal, on surfaces in public places and transport could dramatically cut the threat posed by superbugs. He said "Until recently brass was a relatively commonly used surface. On stainless steel surfaces these bacteria can survive for weeks, but on copper surfaces they die within minutes. We live in this new world of stainless steel and plastic, but perhaps we should go back to using brass more instead."