Regional trends in multidrug-resistant infections in German intensive care units: a real-time model for epidemiological monitoring and analysis.

A new surveillance module for multidrug-resistant (MDR) bacteria was added to the intensive care component of the German Nosocomial Infection Surveillance System. Participating intensive care units (ICUs) report data on all patients colonised or infected with meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EC/KP). To determine the regional distribution of MRSA, VRE and ESBL-EC/KP in Germany, incidence densities (IDs) of these bacteria per 1000 patient-days were calculated for each ICU and pooled for ICUs of five German regions for the years 2005 and 2006. A total of 176 ICUs including 284 142 patients and 1 021 579 patient-days reported data concerning 5490 cases of MDR bacteria. The pooled IDs were 4.54, 0.54 and 0.29 cases per 1000 patient-days for MRSA, ESBL-EC/KP and VRE cases and 1.56, 0.32 and 0.13 per 1000 patient-days for MRSA, ESBL-EC/KP and VRE infections, respectively. While there were no significant differences in the incidence densities of MRSA infections between regions, the IDs of VRE and ESBL-EC/KP infections showed significant regional variation. The regions also differed in the proportion of ICUs per region that reported at least one infection with MRSA, ESBL-EC/KP or VRE in 2005-2006 and these differences ranged from 82% to 91% for MRSA, from 34% to 76% for ESBL-EC/KP and from 8% to 42% for VRE. This new surveillance module enables ICUs to monitor the occurrence of MDR bacteria by comparing local incidence densities with a national reference and shows significant regional variation of MDR bacteria in Germany.