Table 1. Comparison of main ACORN II and ACORN-HAI activities.

Activity	ACORN II	ACORN-HAI
Screening	◦   Community-acquired infections via daily ward reviews (which can include healthcare-associated infections among patient with significant healthcare exposure in 3 months prior to admission) ◦   Hospital-acquired infections via weekly point prevalence surveys	Healthcare-associated infections (which include hospital-acquired infections) via microbiology line lists
Data collection for specific infection syndromes	Various types of community- and hospital- acquired infection syndromes (detailed data collection for E. coli and S. aureus bloodstream infections)	Culture-positive healthcare- associated bloodstream infections and ventilator-associated pneumonia
Follow-up	During weekly point prevalence surveys (for hospital-acquired infections) and at discharge	Weekly during admission and at discharge
Pathogen isolate storage	No pathogen isolate storage required	Storage of pathogen isolates associated with infection episodes
Outcome assessment	Vital status	Vital and functional status