Beyond the Hawthorne effect: reduction of Clostridium difficile environmental contamination through active intervention to improve cleaning practices.

Education and passive observation resulted in a significant improvement in housekeeper disinfection of nontoxigenic Clostridium difficile spores artificially inoculated onto surfaces in C. difficile infection rooms. A further significant reduction occurred with direct supervision and real-time feedback, suggesting that optimal disinfection is achieved by working closely with housekeepers.