Surveillance of nosocomial infections in intensive care units:: Current data and interpretations

The German nosocomial infections surveillance system KISS was established in 1996 using a surveillance protocol based on the National Nosocomial Infections Surveillance (NNIS) System. Meanwhile data from a total of 274 intensive care units (ICU) are available, among them 134 interdisciplinary, 71 surgical, 55 medical, 9 neurosurgical and 5 paediatric ICUs. The data comprise about 6,966 surveillance months with more than 500,000 intensive care patients and more than 1.8 million patient days. A total of 6,888 cases of pneumonia and 2,357 cases of central venous catheter (CVC) associated primary bloodstream infections (BSI) were recorded. Ventilator associated pneumonia rates and CVC associated primary BSI rates are presented, stratified according to the type of the ICU and affiliation to a university, a teaching hospital or another type of hospital. The most frequent pathogens associated with ventilator associated pneumonia were S. aureus (24.1%), followed by P. aeruginosa (16.8%) and Klebsiella spp. (12.1%). In the case of CVC associated primary BSI coagulase negative staphylococci dominated (30.9%) followed by S.aureus (15.4%) and Enterococcli spp. (11.6%). A remarkable increase of Methicillin Resistant Staphylococcus aureus (MRSA) infections was observed during the period from 1997 to 2002. 19.2% of S. aureus associated pneumonia cases and 25.5% of S. aureus associated primary BSI were due to MRSA. KISS data are useful benchmarks for internal quality management, however a careful interpretation is necessary to stimulate infection control efforts.