Michael Behnke

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.

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.

Use of multistate models to assess prolongation of intensive care unit stay due to nosocomial infection

BACKGROUND Reliable data on the costs attributable to nosocomial infection (NI) are crucial to demonstrating the real cost-effectiveness of infection control measures. Several studies investigating this issue with regard to intensive care unit (ICU) patients have probably overestimated, as a result of inappropriate study methods, the part played by NIs in prolonging the length of stay. METHODS Data from a prospective study of the incidence of NI in 5 ICUs over a period of 18 months formed the basis of this analysis. For describing the temporal dynamics of the data, a multistate model was used. Thus, ICU patients were counted as case patients as soon as an NI was ascertained on any particular day. All patients were then regarded as control subjects as long as they remained free of NI (time-to-event data analysis technique). RESULTS Admitted patients (n=1,876) were observed for the development of NI over a period of 28,498 patient-days. In total, 431 NIs were ascertained during the study period (incidence density, 15.1 NIs per 1,000 patient-days). The influence of NI as a time-dependent covariate in a proportional hazards model was highly significant (P< .0001, Wald test). NI significantly reduced the discharge hazard (hazard ratio, 0.72 [95% confidence interval, 0.63-0.82])--that is, it prolonged the ICU stay. The mean prolongation of ICU length of stay due to NI (+/- standard error) was estimated to be 5.3+/-1.6 days. CONCLUSIONS Further studies are required to enable comparison of data on prolongation of ICU length of stay with the results of various study methods.

Costs of nosocomial Clostridium difficile-associated diarrhoea.

Nosocomial Clostridium difficile-associated disease (CDAD) is a common infection in hospitals. A matched case-control study was carried out to determine hospital-wide excess costs due to CDAD. Cases were assessed by prospective hospital-wide surveillance in a tertiary care university hospital in 2006. Nosocomial cases of CDAD (>72h after admission) were matched to control patients without CDAD in a ratio 1:3 using the same diagnosis-related group in the same year, for a hospital stay at least as long as the time of risk of the CDAD cases before infection and a Charlson comorbidity index +/-1. Data on overall costs per case were provided by the finance department. Matching was possible for 45 nosocomial CDAD cases. The difference in the length of stay showed that CDAD cases stayed significantly longer (median 7 days; P=0.006) than their matched controls. The average cost per CDAD patient was euro 33,840. The difference in the cost per patient showed that the cost for CDAD patients was significantly more than for their matched controls (median euro 7,147; 95% confidence interval: 4,067-9,276). Nosocomial CDAD is associated with high costs for healthcare systems. Clinicians should be aware of the financial impact of this disease and the application of appropriate infection control measures is recommended to reduce spread.

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.

Closure of medical departments during nosocomial outbreaks: data from a systematic analysis of the literature

Summary A total closure of an affected medical department is one of the most expensive infection control measures during investigation of a nosocomial outbreak. However, until now there has been no systematic analysis of typical characteristics of outbreaks, for which closure was considered necessary. This article presents data on features of such nosocomial epidemics published during the past 40 years in the medical literature. A search of the Outbreak Database (1561 nosocomial outbreaks in file) revealed a total of 194 outbreaks that ended up with some kind of closure of the unit (median closure time: 14 days). Closure rates (CRs) were calculated and stratified for medical departments, for causative pathogens, for outbreak sources, and for the assumed mode of transmission. Data were then compared to the overall average CR of 12.4% in the entire database. Wards in geriatric patient care were closed significantly more frequently (CR: 30.3%; P <0.001) whereas paediatric wards showed a significantly lower CR (6.1%; P =0.03). Pathogen species with the highest CR were norovirus (44.1%; P <0.001) and influenza/parainfluenza virus (38.5%; P <0.001). If patients were the source of the outbreak, the CR was significantly increased (16.7%; P =0.03). Infections of the central nervous system were most often associated with closure of the ward (24.2%; P =001). A systematic evaluation of nosocomial outbreaks can be a valuable tool for education of staff in the absence of an outbreak, but may be even more helpful for potentially cost-intensive decisions in the acute outbreak setting on the ward.

Risk factors for the development of nosocomial pneumonia and mortality on intensive care units: application of competing risks models

IntroductionPneumonia is a very common nosocomial infection in intensive care units (ICUs). Many studies have investigated risk factors for the development of infection and its consequences. However, the evaluation in most of theses studies disregards the fact that there are additional competing events, such as discharge or death.MethodsA prospective cohort study was conducted over 18 months in five intensive care units at one university hospital. All patients that were admitted for at least 2 days were included, and surveillance of nosocomial pneumonia was conducted. Various potential risk factors (baseline- and time-dependent) were evaluated in two competing risks models: the acquisition of nosocomial pneumonia and discharge (dead or alive; model 1) and for the risk of death in the ICU and discharge alive (model 2).ResultsPatients from 1,876 admissions were included. A total of 158 patients developed nosocomial pneumonia. The main risk factors for nosocomial pneumonia in the multivariate analysis in model 1 were: elective surgery (cause-specific hazard ratio = 1.95; 95% CI 1.33 to 2.85) or emergency surgery (1.59; 95% CI 1.10 to 2.28) prior to ICU admission, usage of a nasogastric tube (3.04; 95% CI 1.25 to 7.37) and mechanical ventilation (5.90; 95% CI 2.47 to 14.09). Nosocomial pneumonia prolonged the length of ICU stay but was not directly associated with a fatal outcome (p = 0.55).ConclusionMore studies using competing risk models, which provide more accurate data compared to naive survival curves or logistic models, should be carried out to verify the impact of risk factors and patient characteristics for the acquisition of nosocomial infections and infection-associated mortality.

Mortality risk factors with nosocomial Staphylococcus aureus infections in intensive care units: results from the German Nosocomial Infection Surveillance System (KISS).

Introduction:As the number of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infections in German intensive care units increases, the problem of MRSA infection as such is becoming ever more serious. The aim of this study was to investigate whether mortality rates from nosocomial MRSA pneumonia and primary bloodstream infections (BSI) differ significantly from those of nosocomial pneumonia and primary BSI caused by methicillin-susceptible S. aureus (MSSA).Methods:For the analysis data from the ICU component of the German nosocomial infection surveillance system (KISS) were used (January 1997 to June 2002). To identify mortality risk factors a logistic regression analysis with step-wise variable selection was conducted including all cases of nosocomial S. aureus pneumonia and primary BSI. The possible risk factors that were evaluated were age > median, male gender, time in the ICU before infection > median, type of ICU, type and size of hospital, intubation, CVC use, total parenteral nutrition, year of investigation, infection caused by MRSA.Results:Data from 274 ICUs and 505,487 ICU patients were recorded and a total of 6,888 cases of nosocomial pneumonia and 2,357 cases of primary BSI identified, of which 1,851 cases of S. aureus pneumonia and 378 cases of S. aureus primary BSI were considered for analysis. 59 of the 349 patients with MRSA pneumonia (16.9%) and 105 of the 1,502 patients with MSSA pneumonia (7.0%) died. 16 of the 95 patients with primary MRSA BSI (16.8%) and 17 of the 283 patients with primary MSSA BSI died (6.0%). Four factors were significantly associated with mortality from S. aureus pneumonia, one of them being pneumonia caused by MRSA (OR = 2.62; CI95 1.69–4.02). Only MRSA was significantly associated with death from S. aureus primary BSI (OR = 3.84; CI95 1.51–10.2).Conclusion:Nosocomial pneumonia and primary BSI from MRSA may be associated with death, but the cause-effect relationship of severity of illness and MRSA remains to be determined due to the limitations of surveillance data.

How often do asymptomatic healthcare workers cause methicillin-resistant Staphylococcus aureus outbreaks? A systematic evaluation

A systematic search was performed to identify outbreaks of methicillin-resistant Staphylococcus aureus infection and colonization caused by healthcare workers (HCWs). Of 191 outbreaks identified, 11 had strong epidemiological evidence that HCWs were the source. In 3 of these outbreaks, asymptomatic carriers were the cause. The frequent practice of screening asymptomatic HCWs should be reconsidered.

Nosocomial infection and antibiotic use: a second national prevalence study in Germany.

BACKGROUND In 2011, seventeen years after the first national study on the prevalence of nosocomial infections and antibiotic use in German hospitals, a second national prevalence study was carried out according to the specifications of the European Centre for Disease Prevention and Control (ECDC). METHODS The ECDC protocol, containing uniform surveillance definitions and ascertainment methods, was implemented. The only infections counted were those that were active or under treatment with antibiotics on the day of the study. In addition to the representative sample required by the ECDC, which consisted of 46 hospitals, further hospitals participated on a voluntary basis. RESULTS Data on 41 539 patients in 132 hospitals were analyzed. The prevalence of infections that had arisen during the current hospital stay was 3.8% in the overall group and 3.4% in the representative sample of 9626 patients in 46 hospitals. The prevalence of all nosocomial infections, including those acquired before the current hospital stay and still present upon admission, was 5.1% in both the overall group and the representative sample. The prevalence of antibiotic use on the day of the study was 25.5% and 23.3% in the two groups, respectively. CONCLUSION The prevalence of nosocomial infection has not changed since 1994, but the prevalence of antibiotic use has increased. In interpreting these findings, one should bear in mind that confounders may have influenced them in different directions: The mean length of hospital stay is now shorter than in 1994, but the mean age of hospitalized patients is higher.