Background: By analysing the data of the intensive care unit (ICU) component of the German national nosocomial infection surveillance system (KISS) during the last ten years, we have observed a steady increase in the MRSA rates (proportions) from 2001 to 2005 and only a slight decrease from 2006 to 2010. The objective of this study was to investigate the development of the incidence density of nosocomial MRSA infections because this is the crucial outcome for patients.
Findings: Data from 103 ICUs with ongoing participation during the observation period were included. The pooled incidence density of nosocomial MRSA infections decreased significantly from 0.37 per 1000 patient days in 2001 to 0.15 per 1000 patient days in 2010 (RR = 0.40; CI95 0.29-0.55). This decrease was proportional to the significant decrease of all HCAI during the same time period (RR = 0.61; CI95 0.58-0.65).
Conclusions: The results underline the need to concentrate infection control activities on measures to control HCAI in general rather than focusing too much on specific MRSA prevention measures. MRSA rates (proportions) are not a very useful indicator of the situation.