Intensified strategies to control vancomycin-resistant enterococci in immunocompromised patients.

Increasing colonization and infection with vancomycin-resistant enterococci (VRE) in immunocompromised patients are associated with increased mortality. Despite contact precautions for VRE control, rapid limitation of its spread is often impossible. We report on a VRE outbreak in a hematologic/oncologic unit including 33 patients. Although 28 of the patients had only VRE colonization, VRE-related infection was probable in 4 patients, and VRE infection of the bloodstream occurred in 1 case. Two patients were identified by VRE screening on admission, 20 were identified by weekly routine VRE screening, and 6 were identified from specimens taken to clarify infections (eg, urine, bronchoalveolar lavage). Five individuals acquired VRE colonization as inpatients (contact patients). Multiple-locus variable-number tandem repeat analysis (MLVA) proved that the outbreak was caused by VanA gene-positive Enterococcus faecium belonging to MLVA genogroup C1(MLVA types 1, 7, 12). The outbreak strains exhibited the potential virulence factor esp(enterococcus surface protein). The outbreak was terminated within 2 months by intensified infection-control measures, including quarantine and the cohorting of patients who tested positive for VRE; however, VRE spread recurred after the measures were discontinued but was again limited by resuming the measures. We conclude that intensive infection-control strategies enable the timely termination of VRE outbreaks, even those involving VRE strains with high epidemic potential on "high-risk wards" (eg, hematologic/oncologic units). Premature discontinuation of infection-control measures may cause recurrence of the VRE spread.

[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 factor analysis of blood stream infection and pneumonia in neutropenic patients after peripheral blood stem-cell transplantation.

The purpose of this study was to analyse risk factors for blood stream infection (BSI) and pneumonia in neutropenic patients who have undergone peripheral blood stem-cell transplantation (PBSCT). Data were taken from the ONKO-KISS multicenter surveillance project. Infections were identified using CDC definitions (laboratory-confirmed BSI) and modified criteria for pneumonia in neutropenic patients. The multivariate analysis was performed using the Fine-Gray regression model for the cumulative incidences of the competing events 'infection', 'death' and 'end of neutropenia'. The risk factors investigated were: sex, age, underlying disease and type of transplant. From January 2000 to June 2004, a total of 1699 patients in 20 hospitals were investigated. In the multivariate analysis, male patients had a significantly higher risk of acquiring BSI than female patients (P=0.002). The risk of acquiring BSI is highest in patients with advanced acute myeloid leukaemia (AML). In the univariate and multivariate analysis, unrelated donor allogeneic transplantation constituted a risk factor for pneumonia (P=0.012). ONKO-KISS provides reference data on the incidence of pneumonia and BSI. The increased risk for BSI in males and patients with advanced AML, and the increased risk for pneumonia in unrelated donor allogeneic PBSCT patients should be targeted to prevent infections in these higher risk groups.

[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.

Reduction of orthopaedic wound infections in 21 hospitals.

INTRODUCTION: The German national nosocomial infections surveillance system (KISS) has been collecting surveillance data from hip and knee prosthesis operations since 1997. The purpose of this article is to investigate whether surveillance and feedback of surgical site infection (SSI) information to the physicians and nurses of participating hospitals lead to reduced SSI rates or not. MATERIALS AND METHODS: Only information from hospitals previously participating for at least 3 years was used for the analysis. Monthly SSI rates were pooled over the 36-month period, beginning in each clinic's case with its first month of participation, the rates then being compared for 12-month periods. Relative risks were calculated for comparison of the SSI rates in the first and third years of participation. A multiple logistic regression analysis with stepwise variable selection was performed to identify significant risk factors, including the year of surveillance after starting surveillance activities. RESULTS: The overall SSI rates were 1.4% for hip prosthesis and 1.0% for knee prosthesis. Fourteen clinics participated in KISS for at least 3 years continuously with HIP prostheses and 21 with knee prostheses. It was possible to include a total of 15,457 hip and 9,011 knee procedures for this analysis. A comparison of data from the first and the third years show a significant SSI reduction with hip procedures, with a relative risk of 0.54 (CI95 0.38-0.77), and a trend towards reduced SSI rates for knee procedures. The multiple logistic regression analysis confirmed that the SSI rate for hip prosthesis was significantly lower in the third year than in the first year of surveillance (OR = 0.57; CI95 0.42-0.78), though for knee prosthesis the level of significance was not achieved. CONCLUSION: A reduction of SSIs following hip and knee prosthesis operations through the introduction of ongoing surveillance and the possibility of using benchmark data for comparison does seem to be possible in many institutions.

Elemental carbon and respirable particulate matter in the indoor air of apartments and nursery schools and ambient air in Berlin (Germany).

UNLABELLED: This study was performed to examine exposure to typical carcinogenic traffic air pollutants in the city center of an urban area. In all, 123 apartments and 74 nursery schools were analyzed with and without tobacco smoke interference and the households in two measuring periods. Simultaneously, the air outside 61 apartment windows as well as the average daily traffic volume were measured. Elemental carbon (EC), the marker for particulate diesel exhaust and respirable particulate matter (RPM) were determined. The thermographic EC analysis was conducted with and without prior solvent extraction of the soluble carbon fraction. Comparison of these two thermographic EC measurements clearly showed that method-related differences in the results, especially for indoor measurements, when high background loads of organic material were present (e.g. tobacco smoke), existed. Solvent extraction prior to EC determination was therefore appropriate. For the first winter measuring period, the EC concentration levels without solvent extraction in the indoor air were about 50% higher than those measured in the spring/summer period. In the second measuring period (i.e. spring/summer), the median EC concentrations after solvent extraction were 1.9 microg/m3 for smokers' apartments and 2.1 microg/m3 for non-smokers' apartments, with RPM concentrations of 57 and 27 microg/m3, respectively. Nursery schools showed high concentrations with median values of 53 microg/m3 for RPM and 2.9 microg/m3 for EC after solvent extraction. A significant correlation between the fine dust and EC concentrations (after solvent extraction) in the indoor and ambient air was determined. Outdoor EC values were also correlated with the average daily traffic volume. The EC ratios between indoor and ambient concentration showed a median of 0.8 (range: 0.3-4.2) in non-smoker households and 0.9 (range: 0.4-1.5) in smoker apartments. Furthermore, the EC/RPM ratio in indoor and ambient air was 0.01-0.15 (median 0.06) and 0.04-0.37 (median 0.09), respectively. PRACTICAL IMPLICATIONS: In the absence of indoor sources a significant correlation with regard to respirable particulate matter (RPM) and elemental carbon concentrations between the indoor and ambient air of apartments was observed. The high degree of certainty resulting from this correlation underscores the importance of ambient air concentrations for indoor air quality. In nursery schools we found higher concentrations of RPM. An explanation of these results could be the high number of occupants in the room, their activity and the cleaning intensity.

Use of terminal tap water filter systems for prevention of nosocomial legionellosis.

Hospital water supplies often contain Legionella spp. and represent a potential source of nosocomial infection, especially for immunocompromised patients or those in intensive care units. Therefore, pathogen-free water should be provided for such high-risk patients. Surveillance of splash water was performed in high-risk patient care areas at Berlin Charité-University Medicine (506 samples) and Medical School Hannover (767 samples) to investigate the ability to provide water that was free from Legionella spp. by the use of disposable, terminal tap water filter systems with non-impregnated, as well as impregnated, filters with prolonged usage intervals. Twenty (Berlin) and 32 (Hannover) water outlets were provided with disposable filters with a pore size of 0.2 microm. Testing of unfiltered tap water revealed growth of Legionella spp. in 53 of 210 (Berlin) and 30 of 32 (Hannover) samples. Non-impregnated, terminal, disposable water filters at taps used for high-risk patient care led to water free from Legionella spp. in 154 of 155 (99.4%) samples after three to four days and in 137 of 141 (97.2%) samples after six to seven days. When testing a new impregnated filter, 255 of 256 (99.6%) samples remained free from Legionella spp. after continuous use for seven days, as recommended by the manufacturers, and also after 10 days. Samples that were positive for Legionella spp. contained 1-4 cfu/mL. We believe that an impregnated filter system is suitable for the prevention of nosocomial Legionellosis in high-risk patient care areas.

Effectiveness of a hospital-wide selective screening programme for methicillin-resistant Staphylococcus aureus (MRSA) carriers at hospital admission to prevent hospital-acquired MRSA infections.

Screening of potential MRSA-positive patients at hospital admission is recommended in German and international guidelines. This policy has been shown to be effective in reducing the frequency of nosocomial MRSA transmissions in the event of an outbreak, but the influence of screening on reducing hospital-acquired MRSA infections in a hospital setting where MRSA is endemic is not yet well-documented. This study describes the effect of hospital-wide screening of defined risk groups in a 700-bed acute care hospital during a period of 19 months. In a cohort study with a 19-month control period, the frequencies of hospital-acquired MRSA infections were compared with and without screening. In the control period, there were 119 MRSA-positive patients, of whom 48 had a hospital-acquired MRSA infection. On the basis of this frequency, a predicted total of 73.2 hospital-acquired MRSA infections was calculated for the screening period, but only 52% of the expected number (38 hospital-acquired MRSA infections) were observed, i.e., 48% of the predicted number of hospital-acquired MRSA infections were prevented by the screening programme. The screening programme was performed with minimal effort and can therefore be recommended as an effective measure to help prevent hospital-acquired MRSA infections.

Surveillance of nosocomial sepsis and pneumonia in patients with a bone marrow or peripheral blood stem cell transplant: a multicenter project.

BACKGROUND: For surveillance of nosocomial bloodstream infections (BSIs) and pneumonia during neutropenia in adult patients who have undergone bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT), a multicenter study--the Hospital Infection Surveillance System for Patients with Hematologic/Oncologic Malignancies (ONKO-KISS)--was initiated in Germany in 2000. METHODS: Nosocomial infections were identified in neutropenic patients by means of Centers for Disease Control and Prevention definitions for laboratory-confirmed BSI and modified criteria for pneumonia. RESULTS: During the first 38-month period of the study (i.e., through December 2003), a total of 1899 patients associated with 28,273 neutropenic days were investigated. Of these, 1173 (62%) had undergone allogeneic and 726 (38%) had undergone autologous BMT or PBSCT. The mean duration of neutropenia was 14.9 days (9.6 and 18.1 days after autologous and allogeneic transplantation, respectively). Overall, 395 BSIs and 168 cases of pneumonia were identified. The pooled mean site-specific incidence density per 1000 neutropenic days was 14.0 for BSI (12.4 and 18.9 for the allogeneic and autologous transplantation groups, respectively) and 5.9 for pneumonia (6.1 and 5.6 in the allogeneic and autologous transplantation groups, respectively). After allogeneic transplantation, 22.4 BSIs per 100 patients and 11.0 cases of pneumonia per 100 patients occurred, whereas 18.2 BSIs per 100 patients and 5.4 cases of pneumonia per 100 patients occurred after autologous transplantation. The majority (57%) of pathogens associated with BSI were coagulase-negative staphylococci. CONCLUSIONS: The ongoing ONKO-KISS project provides unprecedented reference data about the incidence of pneumonia and sepsis among BMT recipients and PBSCT recipients in Germany. These data will be used for further evaluation of the impact of hygiene measures and therapeutic regimens for these patients.

[Surgical site infections in hospitals and outpatient settings. Results of the German nosocomial infection surveillance system (KISS)]. / Postoperative Wundinfektionen nach stationären und ambulanten OperationenErgebnisse aus dem Krankenhaus-Infektions-Surveillance-System (KISS).

About 1,000,000 hospital days attributable to surgical site infections can be expected per year in German hospitals. Among the various measures for prevention, surveillance of surgical site infections is strongly recommended. Therefore, beginning in 1997 the National Reference Center for Surveillance of Nosocomial Infections began to establish a hospital infection surveillance system in order to provide data for prevention and control of these infections. The surveillance system (called KISS) documents postoperative surgical site infections in patients undergoing selected indicator procedures. Today we have an overview of 274,050 procedures for a total of 20 operative indicator procedures. A further surveillance component focussing on surgical site infections in outpatient settings has recently been developed (AMBU-KISS). The participating hospitals and outpatient settings regularly receive their infection rates as well as the equivalent data of all hospitals involved in order to assess the position of their own hospital. However, competent and meaningful interpretation of these data is necessary for internal quality management in order to avoid wrong conclusions. The available results demonstrate that this approach can lead to a substantial reduction of surgical site infections.

Polycyclic aromatic hydrocarbons inside and outside of apartments in an urban area.

In the context of environmental monitoring in Berlin polycyclic aromatic hydrocarbon (PAH) concentrations in air and household dust were measured inside 123 residences (and simultaneously in a sub group in the air outside the windows). The aim of this study was to determine exposure to PAHs in the environment influencing by several factors, for instance, motor vehicle traffic in a populous urban area. Indoor air samplings were carried out in two periods (winter and spring/summer) in smokers and non-smokers apartments. Benzo(a)pyrene (BaP) median values were 0.65 ng m(-3) (winter) and 0.27 ng m(-3) (spring/summer) in smokers' apartments and 0.25 ng m(-3) (winter) and 0.09 ng m(-3) (spring/summer) in the apartments of non-smokers. The median BaP content in ambient air was 0.10 ng m(-3) (maximum: 1.1 ng/m(-3)) with an indoor-outdoor mean concentration ratio of 0.9 in non-smoker households and 5.4 in smoker apartments. In household dust we obtained median values of 0.3 mg kg(-1) (range: 0.1-1.4 mg kg(-1)). We found a significant relation between indoor and outdoor values. Approximately 75% of the variance of indoor air values was caused by the corresponding BaP concentrations in the air outside the apartment windows. Otherwise a significant correlation between indoor air and household dust values cannot be found. Therefore, according to our results, it is suggested that the indoor PAH concentration in non-smoker apartments could be attributed mainly to vehicular emissions.

Surveillance of nosocomial infections in dermatology patients in a German university hospital.

BACKGROUND: Nosocomial infections (NIs) are a growing problem in healthcare today. Thus, surveillance of NIs is an important aspect of modern infection control, which aims to improve the quality of care. OBJECTIVES: To identify overall and site-specific NI rates in dermatology patients in a German university hospital. METHODS: In a prospective study, 1450 patients were surveyed for NIs according to criteria laid down by the Centers for Disease Control and Prevention. Case records were reviewed twice a week, microbiology reports were assessed and the ward staff was consulted. RESULTS: Altogether, 37 NIs were identified in 35 patients, of whom two had two NIs. The overall incidence was 2.5 NIs per 100 patients, and the incidence density was 1.9 NIs per 1000 patient days. Twenty-one patients developed superficial surgical site infections (SSIs). Thirteen of the 21 SSIs occurred after surgical removal of basal cell carcinoma (BCC; 172 in total). This represents an infection rate of 7.6% after surgery for BCC. CONCLUSIONS: Our data suggest that routine surveillance in dermatological wards is not accorded a high priority. However, surveillance of SSIs, especially following surgery for BCC, may be indicated.

Inducibility and potential role of MecA-gene-positive oxacillin-susceptible Staphylococcus aureus from colonized healthcare workers as a source for nosocomial infections.

To determine the carrier rate of methicillin-susceptible mecA-positive Staphylococcus aureus (dormant MRSA) among healthcare workers (HCWs), 447 nurses and physicians from 13 general wards and intensive care units were investigated for nasal or oropharyngeal S. aureus carriage during one year whenever an MRSA patient was treated. Induction of phenotypic resistance in all mecA-positive oxacillin-susceptible aureus was attempted by 24 h exposure to oxacillin and cefotaxime. Organisms from the broth tube with the highest antibiotic concentration and visible growth after incubation were re-exposed for a total of seven repetitive exposures. Two mecA-negative oxacillin-susceptible S. aureus served as negative control. A population analysis before and after antibiotic exposure was performed. A third of the HCWs were found to be S. aureus carriers. Only three nurses were MRSA positive (0.7%). Seven isolates of dormant MRSA were isolated in six nurses and one doctor (1.6%). After four days of repetitive antibiotic exposure six of seven dormant MRSA were highly resistant to oxacillin. Resistance of the two control S. aureus without the mecA gene was not changed by repetitive antibiotic exposure. Two of the seven dormant MRSA were clonally related as shown by pulsed-field gel electrophoresis (PFGE). The PFGE pattern of one dormant MRSA (HCW) was identical to an MRSA (HCW). The pattern of another dormant MRSA was indistinguishable from an MRSA isolated from a patient who was treated at the same time on the same ward suggesting transmission from the HCW to the patient. Dormant MRSA may be isolated twice as often as MRSA from HCWs. Transmission to patients is possible, which may lead to clinical infections. It might be useful to screen methicillin-susceptible S. aureus isolates from HCWs for the mecA gene when recurrent infections with MRSA occur on a ward and a source cannot be found.

Surveillance of nosocomial infections in adult recipients of allogeneic and autologous bone marrow and peripheral blood stem-cell transplantation.

To identify overall and site-specific rates of nosocomial infections (NIs) during the neutropenic, as compared to the non-neutropenic stage of treatment in adult recipients of allogeneic and autologous bone marrow transplantation (BMT) and peripheral blood stem-cell transplantation (PBSCT), a prospective, 54-month study was started at the Haematological Stem Cell Transplantation Unit of the University Hospital of Freiburg, Germany. NI types were identified using modified CDC definitions. A total of 351 patients (14 256 in-patient days, 5026 neutropenic days) were investigated (316/90% allogeneic, 35/10% autologous; BMT: 119 patients, PBSCT: 234 patients). The mean length of neutropenia was 14.3 days (range: 0-66). Antimicrobial prophylaxis for allogeneic transplantation consisted of ciprofloxacin, trimethoprim/sulpha-methoxazole, fluconazole, and metronidazole. In total, 239 NIs were identified in 169 patients (48.1%), and of these 171 (71.5%) occurred during neutropenia (34.0 NIs per 1000 days at risk). The main pathogens were coagulase-negative staphylococci (36.3%), Clostridium difficile (20.4%), and enterococci (10.0%). Site-specific incidence densities during neutropenia vs non-neutropenia were: 13.9 vs 1.6 bloodstream infections (all central line-associated), 11.9 vs 1.8 pneumonias, 3.0 vs 2.9 gastroenteritis, and 1.6 vs 0.3 urinary tract infections. The greatest number of NI in BMT and PBSCT recipients is acquired during neutropenia, and multicentre surveillance programmes should focus on this.

Do conventional cleaning and disinfection techniques avoid the risk of endoscopic Helicobacter pylori transmission?

BACKGROUND AND STUDY AIMS: The aim of the present study was to determine whether endoscopes serve as a reservoir for Helicobacter pylori and whether the disinfection technique currently recommended for manual cleaning and disinfection of the instruments completely removes the risk of H. pylori transmission. PATIENTS AND METHODS: A prospective study was carried out in 400 patients who were undergoing upper gastrointestinal endoscopy for routine clinical indications. The patients' H. pylori status of the patients was identified using a urea detection system (HUT) and culture. H. pylori contamination was assayed by culturing rinsing samples from the endoscopes before and after manual cleaning and disinfection. Gastric biopsies were assayed using rapid urease testing (Helicobacter urease test, HUT) of two antral and gastric body biopsies and cultures. RESULTS: A total of 128 of the 400 patients examined were found to be H. pylori-positive using HUT testing. Endoscopes were contaminated in 54 of the 128 rinsing samples from endoscopes used in H. pylori-positive patients (42 %) before cleaning and disinfection. One of the 128 rinsing samples (0.8 %) was found to be contaminated with H. pylori even after routine manual cleaning and disinfection - indicating that these cleaning and disinfection procedures may be insufficient to eradicate H. pylori from endoscopes completely. No seroconversion was observed during serological follow-up in the patient who had previously been examined with an endoscope contaminated with H. pylori. The patient was still found to be seronegative 5 months after inoculation. CONCLUSIONS: Endoscopes are frequently contaminated with H. pylori immediately after gastroduodenal endoscopy in H. pylori-infected patients. Iatrogenic transmission is possible, as H. pylori can survive manual cleaning and disinfection with 2 % glutaraldehyde, particularly when there is ineffective cleaning before disinfection.

[Proven and unproven hygiene measures in orthopedics]. / Sinnvolle und nicht sinnvolle Hygienemassnahmen in der Orthopädie.

Postoperative wound infections develop in approximately 2-5% of all patients after orthopedic surgery. After urinary tract infection and pneumonia, such wound infections (15%) are the third most frequent type of hospital-acquired infection. In this review we summarize all proven and unproven hygiene measures available in orthopedics, giving special attention to those implemented with the aim of preventing and controlling postoperative wound infections. Routine application only of hygiene procedures of proven efficacy will be an important contribution to economic and ecological quality assurance in hospital.

The practice of perioperative antibiotic prophylaxis in eight German hospitals.

BACKGROUND: Although there is consensus in the international literature on the benefits of using perioperative antibiotic prophylaxis (PAP), there is still considerable scope for improving its use in many hospitals. MATERIALS AND METHODS: In this study, data on the practice of PAP were recorded in eight German hospitals within the framework of a prospective controlled interventional study for the surveillance and prevention of nosocomial infections. RESULTS: A total of 627 surgical procedures (appendectomies, other colorectal procedures, total prosthetic hip replacement) were assessed; 397 with PAP and 224 without PAP; six procedures could not be evaluated. Of the 397 PAP recorded, only 180 (45.3%) were performed correctly in accordance with international standards as a preoperative single dose (19/59 PAP in appendectomies, 72/188 PAP in other colorectal procedures, 89/150 PAP in total prosthetic hip replacement). CONCLUSION: There is still great uncertainty regarding the point in time at which PAP should be administered and its duration. Additional efforts are necessary to improve PAP in accordance with published evidence-based guidelines.

[Reliable and unreliable health measures in surgery]. / Sinnvolle und nicht sinnvolle Hygienemassnahmen in der Chirurgie.

Despite high standards in theatre design, surgical skills and antibiotic prophylaxis, surgical site infections are still a major complication in modern surgery. After urinary tract infections and lower respiratory tract infections they account for 15.8% of all nosocomial infections in Germany [31]. Causes are multiple and only partially exogenous. The single most important (exogenous) risk factor is the technical skill of the surgeon. Not all surgical site infections are therefore preventable by infection control measures alone. Useful and useless infection control measures will be evaluated critically in the following review according to data in the literature.

[Surveillance of postoperative wound infections: reference data of the Hospital Infection Surveillance System (KISS)]. / Surveillance postoperativer Wundinfektionen--Referenzdaten des Krankenhaus-Infektions-Surveillance-Systems (KISS).

BACKGROUND: Surgical site infections (SSI), the third-most-frequent nosocomial infection, are a problem in all fields of surgery. Assessing the level of one's own infection rates is often difficult, since there have been no suitable comparative data available in Germany in the past due to the lack of a uniform method of determining these rates. METHODS: Based on an American model, the Hospital Infection Surveillance System (KISS) has been carrying out a standard recording of SSI since 1997 in meanwhile 132 surgical departments of 89 hospitals. Specially trained hygiene personnel record SSI according to CDC definitions in selected indicator operations. RESULTS: Since January 1997, 1,549 SSI have been recorded in 71,038 operations using 13 different surgical techniques. The risk-ratified SSI rates for each of these surgical techniques are provided and can serve as orientational data for other departments. CONCLUSION: The KISS reference data can help in assessing one's own SSI rates. A prerequisite is surveillance according to the KISS protocol.