When a score of zero is a good thing.
D003428:Cross Infection / Q000453:epidemiology* / Q000517:prevention & control; D006801:Humans; D017053:Infection Control / Q000379:methods*; D007362:Intensive Care Units; D008396:Maryland / Q000453:epidemiology; D009096:Multi-Institutional Systems; D019982:Organizational Case Studies