Krankenhaus Infektions Surveillance System Research Articles

Surveillance of surgical site infections: methodical comparison of the IQTIG and KISS strategies.

Aim: In 2017, the Institute for Quality Assurance and Transparency in Healthcare (IQTIG) introduced a quality assurance system for the surveillance of surgical site infections (SSI) on behalf the Federal Joint Committee. The establishment of the new system was made in parallel to existing methods, such as the “Krankenhaus-Infektions-Surveillance-System” (KISS). The aim of this work was to perform a comparative analysis.Methods: All 2,233 cases at the University Medical Center Goettingen requiring an assessment of the presence of SSI as part of the IQTIG procedure in 2018 and 2019 were evaluated retrospectively according to the KISS protocol.Results: In total, 2,050 patients were included in the comparative evaluation. Overall, 1,779 (79.7%) had a surgical anamnesis (surgery during the stay or in the past), and 1,716 (83.7%) showed identical results for both surveillance strategies. Different results were found for 334 patients (16.3%), with 160 of these (7.8%) positive for SSI according to IQTIG and 174 (8.5%) positive for KISS. Risk factors were identified for a discordant assessment between the methods. Conclusion: The congruence of the two strategies was consistently high over the study period. There is evidence that the efficiency of the documentation algorithm can be increased without the loss of documentation of SSI, while preserving the precision of the documentation through training.

Case vignettes to evaluate the accuracy of identifying healthcare-associated infections by surveillance persons

National surveillance systems depend on accurate and reproducible diagnosis of infections. To investigate the effect of accuracy of diagnosing healthcare-associated infections (HCAIs) on HCAI rates in a national healthcare-associated surveillance system. Data from the validation process from the intensive care unit (ICU) surveillance component of the German Krankenhaus Infektions Surveillance System (KISS; Hospital Infection Surveillance System) were used to calculate the accuracy of diagnosing HCAI for each individual surveillance person (SP) responsible for surveillance of HCAI in the ICU of his or her hospital. Multivariate analyses were performed to identify factors that were attributed to surveillance accuracy. A total of 189 SPs responsible for surveillance in 218 ICUs assessed 30 case vignettes. The chance of belonging to the group of SPs with high accuracy was increased by being a physician (odds ratio: 3.14; P = 0.02) and by being an external SP (odds ratio: 4.69; P ≤ 0.01). ICU HCAI rates depend on the sensitivity of the ICU's SP [incidence rate ratio (IRR): 1.28 (1.07, 1.53); P ≤ 0.01]. High sensitivity increases healthcare-associated urinary tract infection rates [IRR: 1.33 (1.02, 1.75); P = 0.03] and bloodstream infection rates [IRR: 1.33 (1.06, 1.68); P = 0.01]. High specificity was not a significant factor. In light of the link between sensitivity of diagnosing HCAI by case vignettes and the ICU HCAI rates, this validation method can be recommended for validation of other surveillance systems.

Gender-Specific Differences in Surgical Site Infections: An Analysis of 438,050 Surgical Procedures from the German National Nosocomial Infections Surveillance System

Background: Surgical site infections (SSI) are among the most frequent healthcare-associated infections. They impose a substantial burden with increased morbidity and exceeding healthcare costs. Risk factors such as age, diabetes, and smoking status are commonly accounted for in the literature, but few studies address gender differences. Methods: Data from the German Nosocomial Infections Surveillance System (Krankenhaus-Infektions-Surveillance-System (KISS)) from 2005 to 2010 were analysed for cardiac, vascular, visceral, and orthopaedic surgery, with a total of 438,050 surgical procedures and 8,639 SSI. Rates of SSI and isolated pathogens were analysed for gender. Results: Women had a lower rate of SSI (SSI/100 procedures) in abdominal surgery than men (2.92 vs. 4.37; p < 0.001). No gender-specific differences were found in orthopaedic and vascular surgery, while women had a higher risk for SSI in cardiac surgery (5.50 vs. 3.02; p < 0.001). Isolated pathogens showed differences for sensitive Staphylococcus aureus and Pseudomonas aeruginosa, which were more frequent in women (both p = 0.007), while coagulase-negative staphylococci occurred more often in men (18.8 vs. 14.0%; p < 0.001). Conclusion: Gender differences in SSI exist and are procedure-specific. The underlying mechanisms need to be further elucidated so that targeted measures for the prevention of SSI can be developed.

Representativeness of the Surveillance Data in the Intensive Care Unit Component of the German Nosocomial Infections Surveillance System

To assess the representativeness of the data in the Krankenhaus Infektions Surveillance System (KISS), which is a nosocomial infections surveillance system for intensive care units (ICUs) in Germany. Prospective and retrospective surveillance study. Medical-surgical ICUs in Germany. A sample of medical-surgical ICUs from all over Germany, stratified according to hospital size, was randomly selected. Surveillance personnel from the hospitals were trained in surveillance of nosocomial infections, and they subsequently conducted a 2-month surveillance in their ICUs. Data were compared with KISS data for medical-surgical ICUs. During the period from 2004 through 2005, a total of 50 medical-surgical ICUs agreed to participate in our study: 21,832 patient-days were surveyed, and 262 cases of nosocomial infection were registered, 176 of which were cases of device-associated nosocomial infection (100 cases of lower respiratory tract infection, 47 cases of urinary tract infection, and 29 cases of bloodstream infection). The overall incidence density of all types of nosocomial infections was estimated to be 10.65 cases per 1,000 patient-days. Device utilization rates in the study ICUs and in the KISS medical-surgical ICUs were similar. The pooled mean device-associated infection rates were higher in the study ICUs than in the KISS medical-surgical ICUs (10.2 vs 5.1 cases of pneumonia; 2.0 vs 1.2 cases of bloodstream infection; and 2.7 vs 1.2 cases of urinary tract infection), but the pooled mean device-associated infection rates in the study ICUs were comparable to those of the KISS ICUs during their first year of participation in KISS. The incidence density for nosocomial infections in the study ICUs varied according hospital size, with ICUs in larger hospitals having a higher incidence density than those in smaller hospitals. KISS ICUs started with nosocomial infection rates comparable to those found in our study ICUs. Over the years of participation, however, a decrease in nosocomial infections is seen. Thus, rates of nosocomial infection from KISS should be used as benchmarks, but estimations for Germany that are based on KISS data may underestimate the real burden of nosocomial infections.

Is there an association between nosocomial infection rates and bacterial cross transmissions?*

Surveillance data of nosocomial infection rates are increasingly used for public reporting and interhospital comparisons. Approximately 15% of nosocomial infections on intensive care units are the result of patient-to-patient transmissions of the causative organisms. These exogenous infections could be prevented by adherence to basic infection control measures. The association between bacterial cross transmissions and nosocomial infection rates was analyzed. Prospective cohort study during 24 months. Eleven intensive care units from two university hospitals. All inpatients. None. Primary isolates of six indicator organisms (Acinetobacter baumannii, Enterococcus faecalis and E. faecium, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus) cultured from clinical samples or methicillin-resistant S. aureus surveillance testing of all inpatients were genotyped. Indistinguishable isolates in > or =2 patients defined potential episodes of transmissions. Surveillance of nosocomial infection rates was performed according to the German nosocomial infection surveillance system, Krankenhaus Infektions Surveillance System. Transmission events and nosocomial infection rates were pooled by intensive care unit to calculate Spearman's rank-correlation test. During 100,781 patient days, 100,829 microbiological specimens from 24,362 patients were sampled (average investigation density: 1.0 sample per patient and day) and 3419 primary indicator organisms were cultured. Altogether, 462 transmissions (incidence density of 4.6 transmissions per 1000 patient days; range, 1.4-8.4 days) and 1216 nosocomial infections (incidence density of 12.1 per 1000 patient days; range, 6.2-16.6 days) were discerned. Correlation analysis was unable to reveal any association between the incidence of cross transmissions and nosocomial infections, duration of hospitalization, or device use. Differences in nosocomial infection rates between study intensive care units are not explained solely by cross transmissions. Other factors, like the severity of the patient's underlying diseases, the patient's endogenous flora, or invasive procedures, likely have a dominant effect on the magnitude of nosocomial infection rates.

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.

Ten years of KISS: The most important requirements for success

Ten years ago, in January 1997, data collection for the German national nosocomial infection surveillance system was established, which is known by the acronym KISS (Krankenhaus-Infektions-Surveillance-System). Meanwhile KISS was able to demonstrate a beneficial effect from ongoing surveillance activities and appropriate feedback to the users in combination with reference data for ventilator associated pneumonia, primary bloodstream infections and surgical site infections. Significant reductions of infection rates between 20-30% over 3 years periods in the components for intensive care units, operative departments and neonatal intensive care units were demonstrated. Due to our experience the following requirements have to be fulfilled to keep a surveillance system successful over longer periods: close contact between the participating institutions, consideration of new developments, timely regular data feedback and constant reevaluation of the way of data presentation, data validity and demonstration of its contribution to the reduction of healthcare associated infections (HAI). The article describes in more detail how KISS tries to fulfill these requirements.

The national nosocomial surveillance network in Hungary: results of two years of surgical site infection surveillance

In 2004, a secure web-based national nosocomial infection surveillance system was established in Hungary. The system, named NNSR (Nemzeti Nosocomiális Surveillance Rendszer), is based on the US National Nosocomial Infection Surveillance System (NNIS). Surgical procedures, definitions, surveillance methodology and patient risk indices are those established by NNIS. In this paper, we present the results of the first two years of the surgical patient component of our system. During this period, 41 hospitals participated and selected 11 surgical procedures for surveillance. Altogether 15812 procedures were surveyed and 360 resulting surgical site infections (SSI) were recorded. The overall SSI rate was 2.27%. The most commonly selected procedures and corresponding SSI rates were caesarean section (1.31%), herniorrhaphy (2.09%), cholecystectomy (1.52%) and hip replacement (2.91%). Standardised infection ratios (SIR) were calculated for chosen surgical procedures in order to compare against NNIS published rates. SSI rates for colonic surgery, caesarean section and mastectomy were lower than expected according to the NNIS data but higher for cholecystectomy, herniorrhaphy and hip prosthesis infection rates. We intend to recruit more participating hospitals, leading to a robust national database that can be used to target infection control interventions for patients in Hungary.

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.

Risk Factors for Death Due to Nosocomial Infection in Intensive Care Unit Patients: Findings From the Krankenhaus Infektions Surveillance System

To determine risk factors for death among patients with nosocomial pneumonia and patients with primary bloodstream infections (BSI) in intensive care units (ICUs). Prospective cohort study. Data collected from January 1997 through June 2003 from ICUs registered with the Krankenhaus Infektions Surveillance System in Germany. A total of 8,432 patients with nosocomial pneumonia from 202 ICUs and 2,759 patients with nosocomial primary BSI from 190 ICUs. 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. 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. 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

To evaluate whether surgical site infection (SSI) rates decrease in surgical departments as a result of performing active SSI surveillance. Retrospective multiple logistic regression analyses. A group of 130 surgical departments of German hospitals participating in the Krankenhaus Infektions Surveillance System (KISS). 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. 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. 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.

Five years working with the German nosocomial infection surveillance system (Krankenhaus Infektions Surveillance System)

A national surveillance system for nosocomial infections, Krankenhaus Infektions Surveillance System (KISS), was established in Germany as a joint effort by the National Reference Center for Hospital Epidemiology (currently called the National Reference Center for the Surveillance of Nosocomial Infections) and the Robert Koch Institute. To begin with a well-accepted and proven method, surveillance protocols were developed on the basis of the National Nosocomial Infections Surveillance system. Hospitals from all parts of Germany took part voluntarily. There were 4 surveillance components: intensive care departments (227), patients undergoing operation (231 departments), neonatal intensive care departments (23 hospitals), and patients undergoing bone marrow and peripheral blood stem cell transplants (10 hospitals). Five years after the introduction of KISS many hospitals have introduced continuous surveillance activities whereby the various definitions and methods have attained wide acceptance. This has lead to much better understanding and cooperation between clinicians and infection control personnel in preventing nosocomial infections. KISS is considered the national reference database, but continuous evaluation and development of KISS are necessary to react adequately. (Am J Infect Control 2003;31:316-21.)

Are nosocomial infection rates in intensive care units useful benchmark parameters?

The objectives of this study were to determine to what extent the German national nosocomial infection surveillance system (Krankenhaus Infektions Surveillance System, KISS) can take into account the circumstances prevailing in various intensive care units (ICUs) and to establish whether KISS-ICU infection rates can serve as useful benchmark parameters. The investigation focused on three major factors: microbiological monitoring, severity of illness and the duration of surveillance. For each of these factors separate infection rates were calculated for various ICU groups and the differences compared. Significant differences were found for catheter-associated urinary tract infections (CAUTI) with routine monitoring, but not for ventilator-associated pneumonia (VAP). Significant differences were assessed for central venous catheter-associated bloodstream infections (CVC-BSI), considering the average ventilator utilization rate in the ICU as a surrogate parameter for the average severity of illness in its patient group. Surveillance periods of about 1 year were necessary to confirm definite outlier and nonoutlier positions for the majority of the ICUs. Using KISS data for internal orientation, it is possible to note important differences between ICUs when interpreting infection rates; some initial examples of successful use of surveillance data for the reduction of infection rates are already available. However, the use of such data for external assessment is not possible, because external observers are often unable to fully consider important factors in the interpretation of infection rates.