Time-series analysis to observe the impact of a centrally organized educational intervention on the prevention of central-line-associated bloodstream infections in 32 German intensive care units.

BACKGROUND: Prevention measures reduce central-line-associated bloodstream infections (CLABSIs) but are not always implemented. AIM: To investigate the effect of a central educational programme in German intensive care units (ICUs) on CLABSI rates. METHODS: Thirty-two German ICUs with CLABSI rates greater than or equal to the national average were compared with two control groups containing 277 and 67 ICUs. Processes and CLABSI rates were surveyed before, during and two years after the implementation of a year-long intervention programme. Segmented regression analysis of interrupted time series using generalized linear models was performed to estimate the association between the number of CLABSIs per month and time, intervention and other confounders, with the clustering effect within an ICU taken into account. FINDINGS: In total, 508 cases of CLABSI were observed over 266,471 central line (CL)-days. At baseline, the pooled mean CLABSI rate was 2.29 per 1000 CL-days, and this decreased significantly to 1.64 per 1000 CL-days in the follow-up period. Compared with baseline, the relative risk for CLABSI was 0.88 [95% confidence interval (CI) 0.70-1.11] for the intervention period and 0.72 (95% CI 0.58-0.88) for the follow-up period. No changes were observed in either control group. Following successful implementation of the programme, ICUs showed a significant decrease in CLABSI rates. Although rates were already decreasing prior to implementation of the intervention, the invitation to participate in the study, and increased general awareness of CLABSI prevention through use of the comprehensive multi-modal training materials may have had a beneficial effect on practice.

[Deficits in central venous catheter associated bloodstream infection]. / Defizite bei der Prävention der ZVK-assoziierten Sepsis: Wissenslücken oder Complianceprobleme?

BACKGROUND AND OBJECTIVE: Intensive care units (ICUs) with high rates of central venous catheter (CVC) -associated bloodstream infections (BSI) were invited to implement a bundle on BSI prevention during an educational programme which was created by the German national reference center for surveillance of nosocomial infections (NRZ). Training of health care workers (HCWs) was the main component and will be presented in the following. METHODS: The intervention was realized by local infection control staff from April 2006 to March 2007. Modules were lecture, script and poster. Before the intervention HCWs completed an anonymous multiple choice questionnaire about BSI prevention measures. Lectures could be modified in accordance to the ICUs knowledge of prevention measures. Processes and CVC-BSI rates were surveyed and analysed before and after the intervention and also during an additional 24-months follow-up period. RESULTS: Thirty-two ICUs with 1,622 HCWs realized the intervention. Knowledge of BSI prevention of 1,251 HCWs was assessed. Knowledge gaps could predominantly be shown for the favored insertion site and the changing intervals of intravenous tubing for aqueous infusions. One third of HCWs said that a daily CVC's dressing change was indicated. After the intervention ICUs showed a significant decrease in the pooled CVC-BSI rate. ICUs showed a significant decrease of the pooled CVC-BSI rate during the follow-up. CONCLUSION: In this first assessment of more than 1,200 HCWs' knowledge of BSI prevention in German ICUs knowledge gaps could be identified. During the 12-months intervention the implementation of evidence based IC recommendations improved and the pooled CVC-BSI rate decreased significantly.

Risk factors associated with surgical site infections following vascular surgery at a German university hospital.

Surgical site infection (SSI) after vascular surgery is a serious complication increasing morbidity, mortality, and costs for healthcare systems. A 4-year retrospective cohort study was performed in a university hospital with patients who had undergone arterial vascular surgery below the aortic arch. Investigated variables included demographics and clinical data. Forty-four of 756 patients experienced SSI, 29 of which were superficial, five were deep, and 10 had organ/space infections. Coagulase-negative staphylococci (22%), enterococci (20%), and Staphylococcus aureus (18%) were the most common pathogens. Independent risk factors for SSIs were femoral grafting [odds ratio (OR) 6·7], peripheral atherosclerotic disease, Fontaine stages III-IV (OR 4·1), postoperative drainage >5 days (OR 3·6), immunosuppression (OR 2·8), duration of operation >214 min (OR 2·8), and body mass index >29 (OR 2·6). The application of perioperative antibiotic prophylaxis was an independent protective factor (OR 0·2). Patients with certain risk factors for SSIs warrant special attention for infection prevention.

Prolonged duration of operation: an indicator of complicated surgery or of surgical (mis)management?

PURPOSE: The aim of this study was to investigate whether a prolonged operative time should be regarded as an indicator of quality problems in operating rooms or as patient-specific risk factors when analyzing surgical site infection (SSI) rates. METHOD: Data from the SSI component of the German national nosocomial infection surveillance system (KISS) were used to address this question. Eight procedure categories tracked by at least 30 departments participating in KISS were included in the analysis, namely, hip (2 types) and knee prosthesis, breast surgery, hernia repair, C-section, cholecystectomy and colon operations. Various multiple logistic regression analyses were performed for each procedure category to predict duration of operation. Patient factors (sex, age, American Society of Anesthesiologists score, wound contamination class) and hospital factors (hospital status, size, annual volume) were considered. The area under the receiver operating characteristic (ROC) curve was used to evaluate predictive power including patient- and hospital-based factors. RESULTS: A total of 253,454 operations were included in the analysis. In general, the predictive power of the model including all variables for the different procedure types was relatively low (C-index range: 0.57-0.63) and not much higher than that of the models including only patient-based or only hospital-based variables, respectively. The predictive power for the duration of operative time based on the model including only hospital-based variables was as good as or better than that of the model including only patient-based factors. CONCLUSION: Duration of operation is at least partially determined by hospital factors and, consequently, should be used as a quality indicator to compare SSI infections between hospitals, rather than being used as a patient factor to adjust comparisons between hospitals.

Outbreak of carbapenem-resistant Pseudomonas aeruginosa infection in a surgical intensive care unit.

Infection control personnel performing surveillance activities noticed a cluster of patients with isolates of carbapenem-resistant Pseudomonas aeruginosa (CRPA) in the surgical intensive care unit (SICU) of a German University Hospital. An outbreak investigation including a descriptive analysis, a case-control study comparing 15 CRPA case patients with 18 patients with carbapenem-susceptible P. aeruginosa, environmental sampling and pulsed-field gel electrophoresis (PFGE) typing of P. aeruginosa isolates was carried out. Fifteen patients acquired CRPA in the SICU during the outbreak period between 1 July 2006 and 31 October 2006 and PFGE typing of 11 available patient isolates revealed two outbreak strains as well as sporadic CRPA isolates. Both outbreak strains were resistant to penicillins, cephalosporins, carbapenems, aminoglycosides and quinolones, and remained susceptible only to colistin. The most likely mode of transmission was cross-transmission between patients during postoperative wound care with abdominal and/or thoracic drains (odds ratio: 64.33; 95% confidence interval: 5.32-999) and therapy with quinolones (48.37; 3.71-999) being independent risk factors for acquisition of CRPA. No further clusters of CRPA cases were observed after implementation of contact isolation precautions and after healthcare workers were made aware of the likely mode of transmission. This study shows the complex epidemiology of CRPA in a SICU including cross-transmission of two CRPA strains related to postoperative wound care.

New identification of outliers and ventilator-associated pneumonia rates from 2005 to 2007 within the German Nosocomial Infection Surveillance System.

This study presents data for ventilator use and ventilator-associated pneumonia (VAP) rates from the German hospital surveillance system for nosocomial infections (KISS: Krankenhaus Infektions Surveillance System). New Centers for Disease Control and Prevention (CDC) definitions became effective during 2005 and we describe the new method used by KISS to determine individual units with data at extreme ranges. The number of VAP cases per 1000 device-days was calculated and a new visual method, specifically funnel plots, was introduced to identify outliers. The VAP rate will be highly influenced by chance variability if only a few VAP cases are observed during a low number of ventilator-days. Funnel plots take this relationship between event rate and volume of cases into account. A total of 391 intensive care units (ICUs) reported surveillance data from 8 86 816 patients and included 6896 VAPs and 3 113 983 patient-days for the period January 2005 to December 2007. The mean VAP rate according to the new CDC definitions was 5.5 cases per 1000 ventilator-days (median: 4.4). The mean ventilator use in all ICUs was 35.7 (median: 29.3). Funnel plots identified 14.3% as outliers; 34 of them as high, and 22 as low, outliers. Since 2008, visual feedback to the KISS ICUs has been supplied by funnel plots. These are less prone to misinterpretation than histograms and they indicate when investigation is required for increasing VAP.

Reproducibility of the surveillance effect to decrease nosocomial infection rates.

OBJECTIVE: To investigate whether the reduction effect due to participation in a nosocomial infection surveillance system for laboratory-confirmed central venous catheter (CVC)-associated primary bloodstream infection (BSI), ventilator-associated pneumonia (VAP), and surgical site infection (SSI) is reproducible for different time periods, independent of confounding factors that might occur during a specific time period. METHODS: Data from the German national nosocomial infection surveillance system from the period January 1997 through June 2008 were used. CVC-associated BSI data and SSI data were analyzed for 3 starting periods, and VAP data were analyzed for 2 starting periods. Monthly infection rates were calculated for the following 36 months, and relative risks comparing the first and third surveillance years of each period were calculated. RESULTS: A total of 2,399 CVC-associated BSI cases from 267 intensive care units, 3,637 VAP cases from 150 intensive care units, and 829 SSIs following 3 different procedures from 113 departments were analyzed. A significant reduction in VAP was shown for both starting periods investigated (overall relative risk [RR], 0.80 [95% CI, 0.74-0.86]). A significant reduction in CVC-associated BSI was demonstrated for 2 of 3 starting periods (overall RR, 0.83 [95% CI, 0.75-0.91]). A significant reduction in SSI was found for 2 starting periods for knee prosthesis insertion (overall RR, 0.56 [95% CI, 0.38-0.82]), for all of the 3 starting periods for cesarean delivery (overall RR, 0.75 [95% CI, 0.61-0.93]), and for none of the 3 starting periods for endoscopically performed cholecystectomy (overall RR, 0.89 [95% CI, 0.62-1.27]). CONCLUSIONS: The surveillance effect, manifest as a significant reduction of nosocomial infection rates between the first and third years of participation in a surveillance system, was observed independently from the calendar year in which the surveillance activities started.

A point-prevalence study for MRSA in a German university hospital to identify patients at risk and to evaluate an established admission screening procedure.

BACKGROUND: Due to the enormous increase in the number of MRSA-patients, in July 2004, an extended admission screening protocol was implemented in ICUs and surgical wards at Hannover Medical School. PATIENTS AND METHODS: In 2005, a point-prevalence study (also known as a cross-sectional study) was conducted to determine the prevalence of MRSA and Panton-Valentine leukocidin (PVL) among inpatients, to identify patients at risk for MRSA colonization and to evaluate compliance with admission screening. Inpatients were screened by taking cultures from nose, throat and skin lesions. S. aureus isolates were tested for antimicrobial susceptibility and PVL. MRSA was analyzed by staphylococcal protein A (spa) typing. RESULTS: Of 509 inpatients, 145 (28%) were S. aureus carriers. 27 (19%) inpatients were MRSA positive, i.e., the MRSA point-prevalence was 5.3% (95% CI, 3.49; 7.70). spa type t032 was predominant in 67% of the MRSA inpatients. The PVL gene was present in one (0.2%) methicillin-susceptible strain. Comparison with data retrieved from the local hospital MRSA database showed that, the status of 37% of the MRSA had previously remained undetected (10/27). Consequently, MRSA colonization was newly identified in 2.0% (10/509) of the patients. Compliance with admission screening failed in three cases. Nosocomial acquisition was identified in three patients. Four other patients harbouring MRSA were newly identified on wards without routine screening (three neurological, one internal medicine ward). CONCLUSION: Despite extended admission screening, 37% of all MRSA-positive inpatients were missed. The neurological patients were identified as a further risk group and were included in the admission screening procedure established.

Does stratifying surgical site infection rates by the National Nosocomial Infection Surveillance risk index influence the rank order of the hospitals in a surveillance system?

We performed a study to investigate whether stratification of surgical site infection (SSI) rates according to the National Nosocomial Infection Surveillance (NNIS) risk index could lead to a better basis for comparison of surgical units compared with simpler methods. A retrospective analysis of surveillance data of the German national nosocomial infection surveillance system (KISS, Krankenhaus Infektions Surveillance System) was completed with data from 234 volunteer surgical departments. In all, 4275 SSIs of 223 367 operations from 12 surgical procedure categories were surveyed over a 66 month period from January 2001 to June 2006. Active SSI surveillance was performed according to the NNIS method and Centers for Disease Control and Prevention definitions. For each department, two SSI rates were calculated per procedure: the crude infection rate (CIR) and the risk-adjusted standardised infection ratio (SIR) based on the NNIS risk index. Ranking was performed for the departments using both rates. The correlation between the two ranking positions was investigated by Spearman's correlation coefficient (P). For all 12 operative procedure categories, there was a strong correlation between the CIR and the SIR (P > 0.95). A department's rank position does not change remarkably when the CIR, which is easier to understand and simpler to record, is taken into account for comparison instead of the SIR.

[Surgical site infection rates using a laparoscopic approach: results of the German national nosocomial infections surveillance system]. / Wundinfektionen nach laparoskopischen Operationen: Ergebnisse des Krankenhaus-Infektions-Surveillance-Systems.

BACKGROUND: Our aim was to assess the impact of laparoscopy on surgical site infections. METHODS: An analysis was performed using the data of the German national nosocomial infections surveillance system (Krankenhaus-Infektions-Surveillance-Systems, KISS) collected during the period from January 2001 to June 2006. Univariate and multivariate analyses were used to investigate the influence of age, gender, ASA score, duration of surgery, wound contamination class and surgical technique. RESULTS AND CONCLUSIONS: A total of 18,249 appendectomies, 32,912 herniorrhaphies, 42,949 cholecystectomies and 19,523 colon operations were analysed. The overall surgical site infection rate was significantly higher (2.6-fold) for the open approach compared to laparoscopically performed appendectomies. For herniorrhaphies, cholecystectomies and colon operations the corresponding odds ratios were 3.40, 3.22 and 1.20 respectively. Whenever possible a laparoscopic approach should be used.

Risk factors for death due to nosocomial infection in intensive care unit patients: findings from the Krankenhaus Infektions Surveillance System.

OBJECTIVE: To determine risk factors for death among patients with nosocomial pneumonia and patients with primary bloodstream infections (BSI) in intensive care units (ICUs). DESIGN: Prospective cohort study. SETTING: Data collected from January 1997 through June 2003 from ICUs registered with the Krankenhaus Infektions Surveillance System in Germany. PATIENTS: A total of 8,432 patients with nosocomial pneumonia from 202 ICUs and 2,759 patients with nosocomial primary BSI from 190 ICUs. METHODS: The following risk factors were considered in the analysis: age, sex, time in the ICU before onset of infection, type of ICU, type and size of hospital, intubation, central venous catheter use, total parenteral nutrition, and type of pathogen. RESULTS: A total of 750 patients (8.9%) with nosocomial pneumonia and 302 patients (10.9%) with nosocomial primary BSI died. Multiple logistic regression analysis identified treatment in a medical or surgical ICU (odds ratio [OR], 1.55 [95% confidence interval {CI}, 1.32-1.82]) or a hospital with more than 1,000 beds (OR, 2.14 [95% CI, 1.81-2.56]), age older than 65 years (OR, 1.54 [95% CI, 1.31-1.81]), and infection with methicillin-resistant Staphylococcus aureus (OR, 2.39 [95% CI, 1.81-3.12]) or multidrug-resistant Pseudomonas aeruginosa (OR, 3.00 [95% CI, 1.90-4.63]) as independent determinants of death from nosocomial pneumonia. Age older than the median of 63 years (OR, 1.44 [95% CI, 1.12-1.86]) and methicillin-resistant S. aureus as the causative agent (OR, 2.98 [95% CI, 1.81-5.82]) were both associated with increased mortality from primary BSI. The types of infecting pathogens, particularly those resistant to multiple drugs, were also strong outcome predictors among ICU patients. CONCLUSIONS: The study results underline the need for further investigations of the role of antimicrobial resistance in the outcome of patients with nosocomial pneumonia and patients with primary BSI.

Validation of surveillance in the intensive care unit component of the German nosocomial infections surveillance system.

A validation study was performed for the intensive care unit component of the German nosocomial infections surveillance system (Krankenhaus Infektions Surveillance System [KISS]). A total of 286 reported infections and 1,195 medical records with no reported infection from 20 randomly selected KISS intensive care units were reviewed by trained physicians. The mean sensitivity was 66% (median, 81%), and the mean specificity was 99.4% (median, 99.6%).

Reduction of surgical site infection rates associated with active surveillance.

OBJECTIVE: To evaluate whether surgical site infection (SSI) rates decrease in surgical departments as a result of performing active SSI surveillance. DESIGN: Retrospective multiple logistic regression analyses. SETTING: A group of 130 surgical departments of German hospitals participating in the Krankenhaus Infektions Surveillance System (KISS). METHODS: Data for 19 categories of operative procedures performed between January 1997 and June 2004 were included (119,114 operations). Active SSI surveillance was performed according to National Nosocomial Infections Surveillance system (NNIS) methods and definitions. Departments' SSI rates were calculated individually for each year of surveillance and for each operative procedure category, taking into account when the individual departments had begun their surveillance activities. Multiple logistic regression analyses on a single operation basis were carried out with stepwise variable selection to predict outcomes for patients with SSI. The variables included were as follows: the department's year of participation, NNIS risk index variables, patients' age and sex, and the hospitals' structural characteristics, such as yearly operation frequency, number of beds, and academic status. RESULTS: For 14 of 19 operative procedure categories analyzed, there was a tendency toward lower SSI rates that was associated with increasing duration of SSI surveillance. In multiple logistic regression analyses of pooled data for all operative procedures, the departments' participation in the surveillance system was a significant independent protective factor. Compared with the surveillance year 1, the SSI risk decreased in year 2 (odds ratio, 0.84; 95% confidence interval, 0.77-0.93) and in year 3 (odds ratio, 0.75; 95% confidence interval, 0.68-0.82), and there was no change in year 4. CONCLUSION: The SSI incidence was reduced by one quarter as a result of the surveillance-induced infection control efforts, which indicates the usefulness of a voluntary surveillance system.

Reduction of surgical site infections after Caesarean delivery using surveillance.

Since 1997, the Krankenhaus Infektions Surveillance System (KISS) has collected data on surgical site infections (SSIs) following Caesarean delivery (CD). The aim of this study was to determine whether surveillance and feedback of healthcare-associated infections (HAIs) could reduce the infection rate after CD. Only departments that had participated in KISS for at least three years were included in the analysis. The CD infection rates of the first, second and third years of KISS participation were compared for significant differences. The relative risk was calculated for the first and the third year of KISS participation. Multi-variate logistic regression analysis was performed to detect significant risk factors for SSI after CD using the third year of participation as one parameter. Twenty-six of 52 obstetric and gynaecology departments met the study's inclusion criteria. In those 26 departments, 17,405 CD procedures were performed and 331 SSIs were recorded (1.9%). The SSI rate after CD procedures was significantly reduced in the third year of KISS participation (1.6%) compared with the first year of KISS participation (2.4%), with a relative risk of 0.63 [95% confidence interval (CI) 0.48-0.82]. Logistic regression analysis confirmed that KISS participation over three years was an independent factor for the reduction of SSI rate (odds ratio 0.64; 95% CI 0.49-0.83). As shown previously for other types of HAI, this study demonstrated that continuous surveillance and comparison with stratified reference data could reduce SSI infection rates after CD.

Effectiveness of a nationwide nosocomial infection surveillance system for reducing nosocomial infections.

In recent years, several countries have established surveillance systems for nosocomial infections (NIs) on a national basis. Limited information has been published on the effectiveness of these national surveillance systems. The aim of this study was to investigate whether participation in the German national NI surveillance system [Krankenhaus Infektions Surveillance System (KISS)] resulted in reduced rates of NIs. Three major NIs were studied: ventilator-associated pneumonia (VAP) and central-venous-catheter-related primary bloodstream infections (CR-BSIs) in intensive care units (ICUs), and surgical site infections (SSIs) in surgical inpatients. Data were collected from January 1997 until December 2003. Only institutions that had participated in KISS for at least 36 months were considered for analysis. Data from the first 12 months of surveillance were compared with data from the second and third 12-month periods. One hundred and fifty ICUs and 133 surgical departments fulfilled the inclusion criteria. In their first year of participation in KISS, the ICUs had an average VAP rate of 11.2 per 1000 ventilator-days and a CR-BSI rate of 2.1 per 1000 catheter-days. The average SSI rate in the surgical inpatients was 1.6 per 100 operations in their first year of participation. Comparing the infection rates in the third year with the first year, the relative risk (RR) for VAP was 0.71 [95% confidence intervals (CI) 0.66-0.76] and the RR for CR-BSI was 0.80 (95% CI 0.72-0.90). The corresponding RR for SSI was 0.72 [95% CI 0.64-0.80]. Participation in KISS was associated with a significant reduction in these three NIs.

[Responsibility of surgeons for surgical site infections]. / Postoperative Wundinfektionen: Der Chirurg als Täter oder Opfer?

Surgical site infections can be traced to discrepancies in one specific hospital department: the operating suite. Therefore, prevention is often viewed as resting completely on the surgeon. However, the source of micro-organisms responsible for surgical site infections can be endogenous or exogenous. Most infections are believed to be the former, i.e. caused by micro-organisms already resident in the patient's body. Therefore the surgeon can be regarded as suspect only in exceptional cases and usually himself a victim. Prevention is possible not only for exogenous surgical site infection but also many endogenous infections. A multicenter surveillance of infection rates at 130 operative departments participating for at least 4 years in the German National Nosocomial Infection Surveillance System was conducted. A significant 25% reduction in the 3rd year was observed compared with patients who underwent surgery within the 1st year of participation. However, surgeons alone cannot achieve such a decrease, and a team approach is required under most circumstances.

Device-associated infection rates for non-intensive care unit patients.

BACKGROUND: Reference data from intensive care units (ICUs) are not applicable to non-ICU patients because of the differences in device use rates, length of stay, and severity of underlying diseases among the patient populations. In contrast to the huge amount of data available for ICU patients, appropriate surveillance data for non-ICU patients have been missing in Germany. OBJECTIVE: To establish a new module ("DEVICE-KISS") of the German Nosocomial Infection Surveillance System for generating stratified reference data for non-ICU wards. SETTING: Non-ICU patients from 42 German hospitals. METHODS: Monthly patient-days, device-days and nosocomial infections (NIs) (using Centers for Disease Control and Prevention definitions) were counted. Device use rates were calculated, and NI rates were stratified by different medical specialities. RESULTS: From July 2002 through June 2004, among the 77 wards, there were a total of 536,955 patient-days and 74,188 device-days (for CVC-associated primary bloodstream infections, there were 181,401 patient-days and 8,317 central vascular catheter [CVC]-days in 29 wards; for urinary catheter-associated urinary tract infections, there were 445,536 patient-days and 65,871 urinary catheter-days in 65 wards) and 483 NIs (36 bloodstream infections and 447 urinary tract infections). The mean device use rates were 4.6 device-days per 100 patient-days for CVCs (29 wards) and 14.8 device-days per 100 patient-days for urinary catheters (65 wards), respectively. Mean device-associated NI rates were 4.3 infections per 1,000 CVC-days for CVC-associated bloodstream infections and 6.8 infections per 1,000 urinary catheter-days for catheter-associated urinary tract infections. CONCLUSIONS: DEVICE-KISS allows non-ICUs to recognize an outlier position with regard to NIs by providing well-founded reference data for non-ICU patients.

Risk groups for clinical complications of norovirus infections: an outbreak investigation.

Norovirus infections have been described as self-limiting diseases of short duration. An investigation of a norovirus outbreak in a university hospital provided evidence for severe clinical features in patients with several underlying diseases. Clinical outcomes of norovirus infection were defined. Risk-factor analysis targeting underlying diseases and medication was performed using multivariate analyses. In five outbreak wards, 84 patients and 60 nurses were infected (an overall attack rate of 32% in patients, and 76% in nurses). The causative agent was the new variant Grimsby virus. Severe clinical features, including acute renal failure, arrhythmia and signs of acute graft organ rejection in renal transplant patients, were observed in seven (8.3%) patients. In multivariate analyses, cardiovascular disease (OR 17.1, 95% CI 2.17-403) and renal transplant (OR 13.0, 95% CI 1.63-281) were risk-factors for a potassium decrease of >20%. Age >65 years (OR 11.6, 95% CI 1.89-224) was a risk-factor for diarrhoea lasting >2 days. Immunosuppression (OR 5.7, 95% CI 1.78-20.1) was a risk-factor for a creatinine increase of >10%. Norovirus infections in patients with underlying conditions such as cardiovascular disease, renal transplant and immunosuppressive therapy may lead to severe consequences typified by decreased potassium levels, increased levels of C-reactive protein and creatine phosphokinase. In the elderly, norovirus infection may lead to an increased duration of diarrhoea. Therefore patients at risk should be hospitalised early and monitored frequently. Strict preventional measures should be implemented as early as possible to minimise the risk of nosocomial outbreaks.