['The diffusion of national evidence-based practice guidelines and their impact on patient outcomes often go unmeasured.', 'Our objectives were to (1) evaluate implementation and compliance with clinical practices recommended in the new Centers for Disease Control and Prevention (CDC) Hand Hygiene Guideline, (2) compare rates of health care-associated infections (HAI) before and after implementation of the Guideline recommendations, and (3) examine the patterns and correlates of changes in rates of HAI. We used pre- and post-Guideline implementation site visits and surveys in the setting of 40 US hospitals--members of the National Nosocomial Infections Surveillance System--and measured HAI rates 1 year before and after publication of the CDC Guideline and used direct observation of hand hygiene compliance and Guideline implementation scores.', 'All study hospitals had changed their policies and procedures and provided products in compliance with Guideline recommendations; 89.8% of 1359 staff members surveyed anonymously reported that they were familiar with the Guideline. However, in 44.2% of the hospitals (19/40), there was no evidence of a multidisciplinary program to improve compliance. Hand hygiene rates remained low (mean, 56.6%). Rates of central line-associated bloodstream infections were significantly lower in hospitals with higher rates of hand hygiene (P < .001). No impact of Guideline implementation or hand hygiene compliance on other HAI rates was identified. Other factors occurring over time could affect rates of HAI. Observed hand hygiene compliance rates were likely to overestimate rates in actual practice. The study may have been of too short duration to detect the impact of a practice guideline.'] Do dissemination of the CDC 's Hand Hygiene Guideline and impact on infection rates?