[Nationwide surveillance of nosocomial infections in Switzerland--methods and results of the Swiss Nosocomial Infection Prevalence Studies (SNIP) in 1999 and 2002].

The first multi-center prevalence study of nosocomial infections in Switzerland took place in 1996. Since then, the number of participating hospitals has steadily increased. Today, 72 hospitals of various sizes are part of the Swiss-NOSO surveillance network and represent 30% of all Swiss acute care hospitals, which include approximately 10,000 acute care beds. This article describes the methodology of the national prevalence studies and the results of the 1999 and 2002 surveys. The proportion of infected patients was 10.1% and 8.1% in 1999 and 2002, respectively. The highest prevalence occurred in intensive care units. The most prevalent nosocomial infections were surgical site infections, urinary tract infections, pneumonia, and bloodstream infections. Increasingly, crude rates of nosocomial infections serve as a quality indicator and are used for interhospital comparison and benchmarking. This may be misleading due to differences in case-mix between hospitals as shown in the 1999 study. Using a coordinated approach within a national network, surveillance of nosocomial infections has established itself as an indispensible part of infection control and prevention in Swiss hospitals.