Petra Gastmeier

Surveillance nosokomialer Infektionen

The field of hospital hygiene in Germany has undergone some changes in recent years. In addition to the traditional focus on hygiene, epidemiological activities in the field of nosocomial infections have become important for many hospitals. In order to measure these infections, a surveillance system has been established in Germany, which is known under the acronym KISS (Krankenhaus-Infektions-Surveillance-System, system for surveillance of hospital acquired infections). The system is based on the experiences and principles of the American NNIS-system (National Nosocomial Infections Surveillance), but takes into account the local circumstances and possibilities of participating hospitals in Germany. Meanwhile, hospitals can select among 6 KISS modules, which focus on the following topics or areas: intensive care units, neonatology intensive care unit, oncology, surgical patients, patients with venous or urinary catheters, as well as outpatients. KISS data may be used for quality management issues by individual hospitals and for benchmarking between hospitals. The time spent for surveillance in each hospital for one of the modules averages between two and three hours per week. The scientific literature on the subject of surveillance has convincingly shown that this kind of activity is cost-efficient. Cost-effectiveness is likely associated with surveillance activities within the KISS framework, as these activities will have a beneficial effect on nosocomial infection rates in participating hospitals.

The preventable proportion of nosocomial infections: an overview of published reports

The proportion of nosocomial infections potentially preventable under routine working conditions remains unclear. We performed a systematic review to describe multi-modal intervention studies, as well as studies assessing exogenous cross-infection published during the last decade, in order to give a crude estimate of the proportion of potentially preventable nosocomial infections. The evaluation of 30 reports suggests that great potential exists to decrease nosocomial infection rates, from a minimum reduction effect of 10% to a maximum effect of 70%, depending on the setting, study design, baseline infection rates and type of infection. The most important reduction effect was identified for catheter-related bacteraemia, whereas a smaller, but still substantial potential for prevention seems to exist for other types of infections. Based on these estimates, we consider at least 20% of all nosocomial infections as probably preventable, and hope that this overview will stimulate further research on feasible and cost-effective prevention of nosocomial infections for daily practice.

Infection control measures to limit the spread of Clostridium difficile

Clostridium difficile-associated diarrhoea (CDAD) presents mainly as a nosocomial infection, usually after antimicrobial therapy. Many outbreaks have been attributed to C. difficile, some due to a new hyper-virulent strain that may cause more severe disease and a worse patient outcome. As a result of CDAD, large numbers of C. difficile spores may be excreted by affected patients. Spores then survive for months in the environment; they cannot be destroyed by standard alcohol-based hand disinfection, and persist despite usual environmental cleaning agents. All these factors increase the risk of C. difficile transmission. Once CDAD is diagnosed in a patient, immediate implementation of appropriate infection control measures is mandatory in order to prevent further spread within the hospital. The quality and quantity of antibiotic prescribing should be reviewed to minimise the selective pressure for CDAD. This article provides a review of the literature that can be used for evidence-based guidelines to limit the spread of C. difficile. These include early diagnosis of CDAD, surveillance of CDAD cases, education of staff, appropriate use of isolation precautions, hand hygiene, protective clothing, environmental cleaning and cleaning of medical equipment, good antibiotic stewardship, and specific measures during outbreaks. Existing local protocols and practices for the control of C. difficile should be carefully reviewed and modified if necessary.

Compliance With Antiseptic Hand Rub Use in Intensive Care Units: The Hawthorne Effect

OBJECTIVE To determine the influence the Hawthorne effect has on compliance with antiseptic hand rub (AHR) use among healthcare personnel. DESIGN Observational study. SETTING Five intensive care units of a university hospital in Berlin, Germany. PARTICIPANTS Medical personnel were monitored in 2 periods regarding compliance with AHR use when there were indications for AHR use. In the first period, the personnel had no knowledge of being observed. The second observation period was announced to the staff of the intensive care units in advance and information about what the observer would be monitoring was provided. Potential confounders of compliance with AHR use included occupational groups (nurses, physicians, and other healthcare workers), intensive care units, and indications for AHR use before or after any procedure. RESULTS Data were collected from 2,808 indications for AHR use. The overall rate of compliance was 29% (95% confidence interval, 26%-32%) in the first period and 45% (95% confidence interval, 43%-47%) in the second period. A logistic regression analysis with potential confounders revealed a significant odds ratio for the comparison between period 2 and period 1. The differences in compliance with AHR use were statistically significant (P<.001) between the occupational groups (nurses had the highest compliance and physicians had middle compliance) and between indication for AHR use before procedures and indication for AHR use after procedures. CONCLUSIONS The Hawthorne effect has a marked influence on compliance with AHR use, with a 55% increase of compliance with overt observation. This result is consistent throughout subgroups. The rate of compliance with AHR use may in fact be lower than we thought because of results from studies that did not take the Hawthorne effect into account. The results of this study underline the necessity for infection control teams to be on wards as often as possible.

Operating Room Ventilation With Laminar Airflow Shows No Protective Effect on the Surgical Site Infection Rate in Orthopedic and Abdominal Surgery

Objective:To evaluate whether operating room (OR) ventilation with (vertical) laminar airflow impacts on surgical site infection (SSI) rates. Design:Retrospective cohort-study based on routine surveillance data. Patients and Methods:Sixty-three surgical departments participating voluntarily in the German national nosocomial infections surveillance system “KISS” were included (a total of 99,230 operations). Active SSI surveillance was performed according to the methods and definitions given by the US National Nosocomial Infection Surveillance system. Surgical departments were stratified according to type of OR ventilation used: (1) turbulent ventilation with high-efficiency particulate air-filtered air, and (2) HEPA-filtered (vertical) laminar airflow ventilation. Multivariate analyses were performed by the generalized estimating equations method to control for the following variables as possible confounders: (a) Patient-based: wound contamination class, ASA score, operation duration, patients’ age and gender, endoscopic operation; (b) Hospital-based: the number of beds in the hospital, its academic status, operation frequency, and long-term participation in KISS. Results:The risk for severe SSI after hip prosthesis implantation was significantly higher using laminar airflow OR ventilation (1.63 < 1.06; 2.52>), as compared with turbulent ventilation. The adjusted odds ratios for the other operative procedures analyzed were: knee prosthesis 1.76 < 0.80, 3.85>; appendectomy 1.52 < 0.91, 2.53>; cholecystectomy 1.37 < 0.63, 2.97>; colon surgery 0.85 < 0.49, 1.49>; and herniorrhaphy 1.48 < 0.67; 3.25>. Conclusions:Unexpectedly, in this analysis, which controlled for many patient and hospital-based confounders, OR ventilation with laminar airflow showed no benefit and was even associated with a significantly higher risk for severe SSI after hip prosthesis.

How many infections are caused by patient-to-patient transmission in intensive care units?*

Objective:The proportion of intensive care unit (ICU)-acquired infections that are a consequence of nosocomial cross-transmission between patients in tertiary ICUs is unknown. Such information would be useful for the implementation of appropriate infection control measures. Design:A prospective cohort study during 18 months. Setting:Five ICUs from two university hospitals. Patients:All patients admitted for ≥48 hrs. Measurement:ICU-acquired infections were ascertained during daily bedside patient and chart reviews. Episodes of potential cross-transmission were identified by highly discriminating genetic typing of all clinical and surveillance isolates of the ten bacterial species most frequently associated with nosocomial infections in ICUs. Isolation of indistinguishable isolates in two or more patients defined potential transmission episodes. Main Results:During 28,498 patient days, 431 ICU-acquired infections and 141 episodes of nosocomial transmissions were identified. A total of 278 infections were caused by the ten species that were genotyped, and 41 of these (14.5%) could be associated with transmissions between patients. Conclusion:Infections acquired during treatment in modern tertiary ICUs are common, but a causative role of direct patient-to-patient transmission can only be ascertained for a minority of these infections on the basis of routine microbiological investigations.

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.

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

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.

Incidence of healthcare-associated infections in high-risk neonates: results from the German surveillance system for very-low-birthweight infants

Infants with birthweight <1500g (VLBW) are at high risk of healthcare-associated infection (HAI). We present surveillance data from the NEO-KISS surveillance system, collected between 2000 and 2005 by 52 neonatology departments in Germany. Infants were stratified into two birthweight categories (<1000 and 1000-1499 g), and rates of nosocomial bloodstream infection (BSI), nosocomial pneumonia and necrotising enterocolitis (NEC) were calculated. The data presented comprise 8677 VLBW and 339,972 patient-days. The incidence of bloodstream infection was 6.5 per 1000 patient-days (8.5 and 4.0 according to birthweight category). The incidence of central venous catheter (CVC)-associated BSI was 11.1 per 1000 CVC-days and the incidence of peripheral venous catheter (PVC)-associated BSI was 7.8 per 1000 PVC-days. The incidence of pneumonia was 0.9 per 1000 patient-days (1.3 and 0.4 according to birthweight category). The incidence of pneumonia among intubated patients was 2.7 per 1000 ventilator-days, while the incidence of pneumonia among patients receiving continuous nasel positive airway pressure (CPAP) was 1.0 per 1000 CPAP-days. The incidence of NEC was 0.9 per 1000 patient-days (1.1 and 0.6 according to birthweight category). HAI is frequent among VLBW and shows wide variation between neonatology departments. Preventive strategies to reduce infections in these infants should be prioritised.

High prevalence of extended-spectrum-β-lactamase-producing Enterobacteriaceae in organic and conventional retail chicken meat, Germany

OBJECTIVES To determine the prevalence of extended-spectrum β-lactamase (ESBL) production in Enterobacteriaceae in retail chicken meat in Germany. METHODS A total of 399 chicken meat samples from nine supermarket chains, four organic food stores and one butchers shop in two geographically distinct regions (Berlin and Greifswald) were screened for ESBL production using selective agar. Phenotypic ESBL isolates were tested for bla(TEM), bla(CTX-M) and bla(SHV) genes using PCR and DNA sequencing. Antibiotic coresistances were determined and strain typing was performed using PCR-based phylogenetic grouping and XbaI-PFGE. RESULTS A total of 185 confirmed ESBL isolates were obtained from 175 samples (43.9%) from all tested sources. The majority of isolates were Escherichia coli producing ESBL types SHV-12 (n = 82), CTX-M-1 (n = 77) and TEM-52 (n = 16). No differences could be observed in the prevalence of ESBL producers between organic and conventional samples. 73.0% of the ESBL producers showed coresistance to tetracycline, 35.7% to co-trimoxazole and 7.6% to ciprofloxacin. Strain typing of selected E. coli isolates from Berlin revealed identical macrorestriction patterns for several isolates from samples taken from the same stores. CONCLUSIONS This is the first comprehensive study from Germany showing a high prevalence of TEM-, CTX-M- and SHV-type ESBLs in Enterobacteriaceae isolated from retail chicken meat. The high rate of coresistance to different classes of antibiotics in the ESBL producers might reflect the common veterinary usage of these and related substances. There is an urgent need to further evaluate the role of poultry in the transmission of highly resistant ESBL-producing bacteria in humans.