Nosocomial infections and multidrug-resistant organisms in Germany: epidemiological data from KISS (the Hospital Infection Surveillance System)

Abstract

Background: More than 800 hospitals and 586 intensive care units (ICUs) in Germany currently participate in a nationwide surveillance system for nosocomial infections (Krankenhaus-Infektions-Surveillance-System, KISS), which collects data on the frequency of nosocomial infections and pathogens and on the appearance of pathogens of special epidemiological importance.

Methods: Data were collected from ICUs regarding lower respiratory tract infections, primary sepsis, and urinary tract infections and on the temporal relation of these types of infection to the use of specific medical devices (invasive ventilation, central venous catheters, and urinary catheters). On the basis of these data, device-associated infection rates (number of infection per 1000 device days) were calculated for different types of ICUs. KISS also collected data on all ICU patients colonized or infected with selected multidrug-resistant organisms (MDRO) and on all hospitalized patients with methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile-associated diarrhea (CDAD).

Results: Device-associated infection rates ranged from 0.9 to 9.6 per 1000 device-days, depending on the type of infection and the type of ICU. An extrapolation from these figures yields an estimate of 57 900 ICU-acquired infections occurring in Germany each year. The most common MDRO in ICU patients is MRSA. The frequency of MRSA has remained stable in recent years, but that of other MDROs among ICU patients is rising. Hospitalized patients are twice as likely to acquire CDAD as they are to acquire MRSA.

Conclusion: Nosocomial infections are common in the ICU. The percentage of ICU patients with MDRO is low, but rising. Future preventive strategies must address this development.

Figure 1

Number of intensive care units (ICUs) according to ICU type in the ICU-KISS reference data 2005–2009

Figure 2

Device-associated infection rates stratified by ICU type; LRTI, lower respiratory tract infections; BSI, bloodstream infections; UTI, urinary tract infections

Figure 3

MRSA prevalence upon admission to ICU (MRSA patients/100 patients) as bars; incidence density of ICU-acquired MRSA (patients with nosocomial MRSA/1000 patient-days) as a line for the period from 2005 to 2009

Figure 4

Total MDRO prevalence (patients with MRSA/ESBL/VRE per 100 patients) during ICU hospitalization for the period from 2005 to 2009

Figure 5

Incidence density of nosocomial CDAD and MRSA per 1000 patient-days in hospitals for 2008