Does the Architecture of Hospital Facilities Influence Nosocomial Infection Rates? A Systematic Review

Objective:

To review the evidence regarding the effects of interventions to improve hospital design and construction on the occurrence of nosocomial infections.

Methods:

Systematic review of experimental and non-experimental, architectural intervention studies in intensive care units (ICUs), surgical departments, isolation units, and hospitals in general. The studies dated from 1975, and were in English, French, German, Italian, and Spanish. Regardless of format, the studies were identified through seven medical databases, reference lists, and expert consultation.

Results:

One hundred seventy-eight scientific articles were identified; however, none of these described a meta-analy-sis, systematic review, or randomized, controlled trial. Most of the articles were categorized at the lowest level of evidence (expert judgment or consensus statements). Only 17 described completed concurrent or historical cohort studies matching the inclusion criteria (ICUs, 9; surgical departments, 4; isolation units, 2; hospitals in generai, 2). The interventions generally included a move to other premises or renovation. However, in many studies, the staff-to-patient ratio was also improved. Some studies showed lower infection rates after intervention, but this finding cannot be generalized because of confounding and fre-quently small study populations.

Conclusions:

The lack of stringent evidence linking hospital design and construction with the prevention of nosocomial infection is partly attributable to the multifactorial nature of these infections, and some improvement will be seen if basic conditions such as the availability of sufficient space, isolation capac-ity, and facilities for handwashing are met. However, to our knowledge, other factors, especially the improper hand hygiene of medical staff, have greater impact.

Practical Aspects for Cost Reduction in Hospital Infection Control

Nosocomial infections consume a significant amount of the total hospital budget. This article describes some practical aspects for cost reduction in hospital infection control. Within one year total savings of 91.000 DM* could be achieved by discontinuing unnecessary disinfection procedures. Within six years 2,27 million DM could be saved by discontinuing unnecessary infection control procedures or employing cheaper methods. Of the total antibiotic costs 25% can be reduced by certain measures.

Surveillance of antimicrobial use and antimicrobial resistance in German intensive care units (SARI): a summary of the data from 2001 through 2004

Objective:

To report the experience gained over 4 years in working with the German SARI project (Surveillance of Antimicrobial Use and Antimicrobial Resistance in Intensive Care Units), and to compare SARI with data from the Swedish STRAMA and the US AUR surveillance system.

Methods:

Prospective unit and laboratory based surveillance was carried out in 40 German ICUs from 2001 through 2004. WHO 2004 definitions of defined daily doses (DDD) per 1,000 patient days (pd) were used to express antimicrobial consumption (AD). Apart from the proportion of resistant isolates (RP), the incidence density of resistant isolates (RD) was calculated on the basis of the number of resistant isolates per 1,000 pd. To determine the changes over time, the Wilcoxon signed rank test for paired samples was used.

Results:

From 1/2001 through 12/2004, 40 ICUs provided data on 53,399 isolates, a total of 789,569 DDD and 597,592 pd. Total AD ranged from 427 to 2,798, with the median being 1,351. There was no statistically significant change in total antimicrobial use, but a statistically significant decrease was observed in the use of aminoglycosides. RD was highest for MRSA with 4.4 resistant isolates/1,000 pd followed by imipenem resistant Pseudomonas aeruginosa with 1.7 resistant isolates/1,000 pd. The corresponding RPs were 21.5% and 23.2%. Over the 4-year period (2001–2004), significant increases were seen in the RDs of third generation cephalosporin and ciprofloxacin resistant Escherichia coli. In 2004, the mean RD reached 0.28 and 1.41, respectively. In comparison, the RP of selected pathogens was highest in the US ICUs and lowest in Swedish ICUs, with the exception of imipenem resistant P. aeruginosa.

Conclusion:

Antibiotic consumption remained stable over a period of 4 years, (the mean being 1,321 DDD/1,000 pd). The same applied to the situation regarding resistance in Staphylococcus aureus, enterococci and P. aeruginosa. For most pathogens the RP was higher in SARI ICUs than in Swedish ICUs, but lower than in US ICUs.

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.

Stenotrophomonas maltophilia and antibiotic use in German intensive care units: data from Project SARI (Surveillance of Antimicrobial Use and Antimicrobial Resistance in German Intensive Care Units)

Risk factors for the selection of Stenotrophomonas maltophilia were analysed by correlating antimicrobial use and structure parameters (e.g. hospital type) with the incidence density of S. maltophilia and the percentage of S. maltophilia isolated from 39 intensive care units (ICUs). SARI (Surveillance of Antimicrobial Use and Antimicrobial Resistance in German Intensive Care Units) is a prospective unit- and laboratory-based surveillance system that collects data on the 13 most important organisms responsible for nosocomial infections. The percentage of S. maltophilia among these organisms and the number of S. maltophilia per 1000 patient-days were calculated. The data were subsequently correlated with antibiotic use density calculated in defined daily doses (DDDs) per 1000 patient-days and structure parameters. The data covered a total of 28 266 isolates and 431 351 DDDs. The antibiotic use density ranged from 427 to 2218, with the median being 1346. Over the two-year period, the median of S. maltophilia per 1000 patient-days was 1.4 (range 0-7.6). Calculation of antibiotic use and S. maltophilia per 1000 patient-days showed a significant positive correlation with the use of carbapenems, ceftazidime, glycopeptides and fluoroquinolones, as well as with total antibiotic use. In the multiple logistic regression analysis, carbapenem use and >12 ICU beds were independently and positively associated with a high number of S. maltophilia per 1000 patient-days. Benchmarking data provided for incidence densities of S. maltophilia in ICUs revealed the heterogeneous situation of the burden of S. maltophilia in individual ICUs. The multi-centre data showed that carbapenem use and >12 ICU beds were independent risk factors for the isolation of S. maltophilia.

Is the prevalence of Stenotrophomonas maltophilia isolation and nosocomial infection increasing in intensive care units?

The study presented here was conducted over a period of 4 years (2001-2004) to investigate changes in the number of S. maltophilia isolates detected per 1,000 patient days and to look at the incidence density of nosocomial infections caused by S. maltophilia. The analysis was based on data provided by 34 German intensive care units participating continuously in the national project "Surveillance of Antimicrobial Use and Resistance in ICUs"; 31 of these ICUs reported nosocomial infections to the German infection surveillance system, KISS, during the study period.

Antibiotic use in two cohorts of German intensive care units

Antibiotic use was evaluated in two cohorts of intensive care units (ICUs) in Germany. One cohort included ICUs participating in a surveillance programme (N=34) collecting antibiotic use and bacterial resistance data, with quarterly feedback. The second ICU cohort was from a cross-sectional study and represented a sample from hospitals in South-west Germany (N=58). Two dose definitions were used. These were the World Health Organization/Anatomical Therapeutic Chemical Classification (ATC) 2001 definition of defined daily dose (DDD), and a definition of recommended daily dose (RDD) that better reflected the currently prescribed dosages of parenteral drugs for hospitalized patients. Data were expressed as DDD or RDD per 100 patient-days. It was determined whether hospital size and affiliation, year of study and ICU type had an influence on overall use of antibiotics. Overall use differed between the two ICU cohorts irrespective of the dose definitions used. High use of antibiotics was primarily associated with hospital affiliation (university vs non-university) and hospital size. Mean overall use of antibiotics in non-university hospital ICUs ranged between 106 and 111 DDD/100 (59 and 67 RDD/100) for different hospital size categories, compared with 140 DDD/100 (87 RDD/100) in university hospital ICUs. In conclusion, in order to compare the use of antibiotics between ICU cohorts and to assess trends over time, data adjustment is required for hospital affiliation and size.

Temporal changes in bacterial resistance in German intensive care units, 2001–2003: data from the SARI (surveillance of antimicrobial use and antimicrobial resistance in intensive care units) project

Conservative testing revealed a stable antibiotic resistance situation for Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Enterobacter cloacae in 32 German intensive care units (ICUs) actively participating in the SARI (surveillance of antimicrobial use and antimicrobial resistance in ICUs) project over a three-year period (2001--2003). No significant changes were shown for methicillin-resistant S. aureus (MRSA) (P=0.501; the MRSA rate increased in 18 ICUs and decreased in 14 ICUs). The only exception was an increase in ciprofloxacin-resistant E. coli.

Pseudocontamination of blood components with Burkholderia cepacia during quality controls

We report on a pseudooutbreak of Burkholderia cepacia because of the use of a contaminated disinfectant during quality controls in a university blood bank. No septic reactions associated with transfusions had been reported in patients over the last 6 months. Analysis of the individual quality control procedures showed that a disinfectant based on a quaternary ammonium compound (QAC) had been used in order to disinfect the rubber stopper of the blood culture bottle. B. cepacia was found in a sample taken from this disinfectant, which was prepared with concentrate and tap water according to the manufacturer's instructions. The four isolates (one in disinfectant and three in blood components) were found to be identical in their biochemical reactions and resistance patterns. QAC-based disinfectants are not efficacious against a part of the spectrum of gram-negatives and are therefore inadequate. After introduction of an alcohol-based preparation, no more cases of B. cepacia contamination have been identified.

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.

Comparison of economic and environmental impacts between disposable and reusable instruments used for laparoscopic cholecystectomy

BACKGROUND

The economic and environmental effects were compared between disposable and reusable instruments used for laparoscopic cholecystectomy. Special consideration was given to the processing of reusable instruments in the Miele G 7736 CD MCU washer disinfector and the resultant cost of sterilization.

METHODS

The instruments frequently used in their disposable form were identified with the help of surgeons. Thus, of all the instruments used for laparoscopic cholecystectomy, the disposable and reusable versions of trocars, scissors, and Veress cannula were compared.

RESULTS

For the case examined in this study, the performance of laparoscopic cholecystectomy with disposable instruments was 19 times more expensive that for reusable instruments. The higher cost of using disposable instruments is primarily attributable to the purchase price of the instruments. The processing of reusable instruments has little significance in terms of cost, whereas the cost for disposing of disposable instruments is the least significant factor. The number of laparoscopic cholecystectomies performed per year does not substantially influence cost. In the authors' opinion, assessment of the environmental consequences shows that reusable instruments are environmentally advantageous.

CONCLUSIONS

Considering the upward pressure of costs in hospitals, disposable instruments should be used for laparoscopic cholecystectomy only if they offer clear advantages over reusable instruments.

[SARI: surveillance of antibiotic use and bacterial resistance in German intensive care units. Correlation between antibiotic use and the emergence of resistance]

Intensive care units (ICUs) are considered to be high-risk areas for the emergence and spread of multiresistant bacterial pathogens. In Germany, there are no representative epidemiological data on antibiotic resistance, on the use of antibiotics in ICUs, or on the correlation between antibiotic use and the emergence of resistance. Project SARI (surveillance of antibiotic use and bacterial resistance in ICUs), which as a part of the epidemiological network Spread of Nosocomial Infections and Resistant Pathogens (SIR) is supported by the German Ministry of Science and Education, started in February 2000 and meanwhile includes data on antibiotic use and resistance rates in 38 medical, surgical, and interdisciplinary ICUs. To date (February 2000-June 2003), a total of 1142 months, 413,065 patient days, and 550,288 defined daily doses (DDDs in accordance with the WHO) have been covered with a mean antibiotic usage density (AD) of 1335 DDDs/1000 patient days and resistance data on 37,612 isolates from ICUs. Ciprofloxacin use and MRSA correlate significantly, as do imipenem use and the rate of imipenemresistant P. aeruginosa. The genodiversity of P. aeruginosa is lower in ICUs with high resistance rates and low use of imipenem than in ICUs with high resistance rates and high use. This is an indirect parameter of transmission of identical strains. The epidemiological data of SARI form a basis for improved antibiotic and infection control management in ICUs (http://www.sari-antibiotika.de).

Antibiotic use in Germany and European comparison

In view of increasing rates of antibiotic resistance worldwide and decreased research and development of new antibacterial compounds, programmes helping to better understand the complex relationship between antibiotic consumption and emergence of resistance have gained importance. Consequently, in addition to increased support for research projects that establish prospective surveillance and evaluation of antibiotic resistance and antimicrobial drug use, the EU has passed directives addressing political leadership in this respect. Information on antibiotic use in Germany is now available from databases independent from cost-oriented market research studies. This information allows estimation of antibiotic use in ambulatory and hospital care as compared with to other EU countries. According to results of current projects, the frequency of national antibiotic use in ambulatory care in Germany (4948 defined daily doses per 1000 population per year) falls within the lower third of EU countries. Upper boundaries in regional variation in antibiotic use are still much lower than values for high-use countries like France, Spain and Portugal. Hospital antibiotic use, in contrast, appears to be in the range of that reported for other countries. However, only rough estimates of hospital antibiotic use are available for Germany as well as most other EU countries due to data usually derived from non-representative hospital sampling.

Effects of caspofungin (MK-0991) and anidulafungin (LY303366) on phagocytosis, oxidative burst and killing of Candida albicans by human phagocytes

The objective of the present study was to investigate the influence of the new echinocandins caspofungin (MK-0991) and anidulafungin (LY303366) on human phagocytes. Phagocytosis, oxidative burst and intracellular killing of Candida albicans were analyzed by flow cytometry. Neither caspofungin nor anidulafungin significantly influenced phagocytosis. Only caspofungin significantly influenced oxidative burst after 15 min of incubation ( P<0.05). Both caspofungin and anidulafungin improved intracellular killing rates of C. albicans after 2 h of incubation (42.4% and 43.2%, respectively, compared to 37.9% in controls; P<0.05). In conclusion, caspofungin significantly improves oxidative burst and intracellular killing, which may be advantageous for clinical therapy.

Hospital infection control in Europe: evaluation of present practice and future goals

The objective of this study was to assess current infection control practice in Europe and its structure, future research priorities, and how infection control should be organised. A questionnaire was sent to 223 hospital infection control physicians throughout Europe, of whom 54 in 18 countries responded. With respect to future research priorities in infection control in Europe, the largest proportion (69%) of the infection control specialists sampled expressed the need for standardisation of surveillance systems for international comparison of nosocomial infection rates. The results of this survey might help to create a basis for standardised guidelines which take into account European-wide interests.

[Quality assurance in intensive care medicine. SARI-surveillance on antibiotic use and bacterial resistance in intensive care units]

Intensive care units (ICUs) are high risk areas for emergence and spread of multiresistant bacterial pathogens. In Germany, there are no representative epidemiological data on antibiotic resistance, prophylactic or therapeutic use of antibiotics in ICUs, or on the correlation between antibiotic use and emergence of resistance. Supported by the German Ministry of Science and Education, project SARI (Surveillance on antibiotic use and bacterial resistance in ICUs) started in 02/2000 and now includes data on antibiotic use and resistance rates in 35 medical, surgical and interdisciplinary ICUs. To date (2/2000-12/2002), a total of 939 participant months, 339,461 patient days and 452,282 defined daily doses (DDD) have been covered with a mean antibiotic usage density (AD) of 1,332 DDDs/1,000 patient days and resistance data on 31,189 isolates from ICUs. The design of the project and first results of SARI are presented. The epidemiological data of SARI form a basis for improved antibiotic and infection control management in ICUs (http://www.sari-antibiotika.de).

Nosocomial outbreak of norovirus gastroenteritis and investigation of ABO histo-blood group type in infected staff and patients

The blood groups were analysed of staff and patients (N=45) infected during two nosocomial outbreaks of norovirus gastroenteritis at a German University hospital. Persons with O phenotype were significantly less affected than was expected from the normal distribution of blood group types in Southwest Germany (OR 2.45; 95% CI 1.22-4.95; P=0.01).

Design of a surveillance system of antibiotic use and bacterial resistance in German intensive care units (SARI)

BACKGROUND

Data on antibiotic consumption and bacterial resistance are important for benchmarking, ensuring quality of antibiotic treatment and helping to understand the relationship between the use of antibiotics and the emergence of resistance.

METHODS

The SARI project is an ecological study that has established laboratory-based surveillance in German intensive care units (ICU). Resistance rates of 13 sentinel pathogens are reported and certain alert organisms are sent for genotyping and retesting of antimicrobial resistance.

RESULTS

The project, initiated in February 2000, now includes 35 ICUs generating a total of 266,013 patient days, 354,356 defined daily doses (DDD) and providing susceptibility data on 21,354 isolates. Pooled antibiotic usage density (AD = DDD/1,000 patient days) was highest for penicillins with lactamase inhibitor (AD 338.3) followed by quinolones (AD 155.5) and second-generation cephalosporins (AD 124.6). Total AD was calculated as 1,337 DDD/1,000 patient days. Resistance rates (RR) for laboratories testing according to the German Industrial Standard (DIN) were 19.3% for methicillin-resistant Staphylococcus aureus (MRSA), 9.5% for ciprofloxacin-resistant Escherichia coli and 25.4% for imipenem-resistant Pseudomonas aeruginosa. 40% of the laboratories did not identify the extended spectrum beta lactamase production of a Klebsiella pneumoniae strain.

CONCLUSION

Focusing on German ICUs, the SARI surveillance system provides a concept that produces a benchmark for the link between antibiotic resistance and consumption.

Comparison of infectious waste management in European hospitals

A research project sponsored by the EC-LIFE programme was conducted to compare waste management in five different European hospitals. A comparison of the regulations governing current waste management revealed different strategies for defining infectious hospital waste. The differences in the infrastructure were examined and the consequences for waste segregation and disposal were discussed under economic and ecological aspects. In this context the definition of infectious waste is very important.

Comparative in vitro activity of piperacillin, piperacillin–sulbactam and piperacillin-tazobactam against nosocomial pathogens isolated from intensive care patients

We investigated the antimicrobial activity of piperacillin-tazobactam versus piperacillin-sulbactam against common nosocomial pathogens (n = 565) isolated from intensive care patients. For Gram-positive bacteria, antimicrobial susceptibilities to the two piperacillin-beta-lactamase inhibitor combinations were almost identical. For Gram-negative bacteria, piperacillin-tazobactam exhibited greater activity against Escherichia coli and Proteus vulgaris than piperacillin-sulbactam. Both combinations, however, were equally effective against the other Enterobacteriaceae and Pseudomonas aeruginosa isolates. Piperacillin-sulbactam exhibited better antimicrobial activity against Acinetobacter baumannii. Our findings might prove important for the appropriate choice of antibiotic therapy with beta-lactam-beta-lactamase inhibitor combinations.

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.

Influence of mistletoe ( Viscum album) extracts on phagocytosis/burst activity of human phagocytes

The aim of the present study was to examine the in vitro effects of various mistletoe extracts on human phagocytes. Phagocytosis, oxidative burst, and intracellular killing were analyzed by flow cytometry. None of the mistletoe preparations investigated exhibited significant phagocytosis-enhancing properties. Different mistletoe lectin concentrations ranging from 0.025 to 20 ng/ml showed only marginal influence on phagocyte activity. Contrary to the opinion of numerous practitioners of complementary medicine, the mistletoe preparations tested do not enhance phagocytic function.

Comparison of PCR-based methods for typing Escherichia coli

OBJECTIVE

To establish a library typing system appropriate for studying cross-transmission of Escherichia coli.

METHODS

Eighteen epidemiologically unrelated isolates were genotyped by means of pulsed-field gel electrophoresis (PFGE), random amplified polymorphic DNA (RAPD), repetitive (rep) PCR, and fluorescent amplified fragment length polymorphism (AFLP). Fingerprints were analyzed either by Pearson correlation or, in the case of AFLP, by Dice coefficients employing the novel 'uncertain band' software tool from GelCompar II. During a nine-month period, 112 isolates taken from 93 patients hospitalized in five intensive care units were analyzed by use of the two most discriminative PCR typing methods.

RESULTS

Genotyping by RAPD and rep-PCR revealed insufficient discrimination. Among 18 epidemiologically unrelated strains with 17 different PFGE patterns, IS3 rep-PCR and AFLP distinguished 10 and 18 types, respectively. Comparison of the different methods for analysis of AFLP fingerprints showed that the Dice coefficients, which ignore 'uncertain bands', offered the best concordance with visual interpretation. Consecutive isolates originating from the same patient differed in less than three fragments.

CONCLUSIONS

AFLP analysis showed the highest discriminative capacity for PCR typing of E. coli isolates. Analysis of fingerprints employing the Dice coefficients proved the most efficient method for an automated software-based retrieval of visually indistinguishable genotypes in an AFLP fingerprint database.

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.

Diversity of Staphylococcus aureus strains isolated from two European regions with different prevalences of methicillin resistance

The genodiversity of Staphylococcus aureus isolates from the Nottingham region of the United Kingdom was compared with isolates from the Freiburg region of Germany. The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) isolates was higher in Nottingham than in Freiburg. In patients from Nottingham hospitals, 80% of MRSA isolates were classical epidemic MRSA-15, but genotypic variants of epidemic MRSA-15 comprised 72% of isolates from Nottingham community-based patients. In contrast, MRSA isolates from Freiburg showed greater diversity, but 47% and 23% of isolates, respectively, belonged to two predominant MRSA genotypes found in isolates from both hospitalised and community-based patients. The results suggest that genodiversity becomes increasingly more confined in settings with a higher frequency and longer duration of MRSA prevalence.

Effect of skin disinfection with octenidine dihydrochloride on insertion site colonization of intravascular catheters

BACKGROUND

We investigated the efficacy of two commercially available, alcohol-based antiseptic solutions in decontaminating the insertion site of central lines. One solution contained the bispyridine octenidine dihydrochloride.

PATIENTS AND METHODS

Inpatients receiving either a central venous catheter (CVC) or a peripherally inserted central catheter (PICC) were alternately assigned to different skin disinfection regimens at the insertion site: (A) 0.1% octendine dihydrochloride with 30% 1-propanol and 45% 2-propanol, (B) 74% ethanol with 10% 2-propanol. Quantitative skin cultures were obtained from the insertion site at predetermined intervals.

RESULTS

A total of 60 patients received 12 CVCs and 47 PICCs (no significant difference with respect to gender, age and catheter type). In total, 90 cultures were assessed in each group. The median colony-forming unit (cfu) counts per 24 cm(2) (group A vs B) were 2,270 vs 2,950 before, 20 vs 40 following and 860 vs 1,210 24 h after catheter insertion, respectively. A statistically significant difference in the efficacy of skin decontamination was seen between groups in culture set (3) and in the difference between culture sets (2) and (3) (Wilcoxon rank sum test).

CONCLUSION

Octenidine/propanol appears to be more effective than alcohol (ethanol/propanol) alone in reducing microflora of the skin at the PICC/CVC insertion site over a 24-h period.

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.

Rapid PCR-based identification of methicillin-resistant Staphylococcus aureus from screening swabs

A PCR identification of methicillin-resistant Staphylococcus aureus (MRSA), obviating the need for subculture on agar media, was investigated. The combination of MRSA detection by mecA femB PCR with prior enrichment in selective broth was tested for 439 swabs. PCR identified 36 MRSA-positive samples, in concordance with conventional methods.

Nosocomial pneumonia: a cost-of-illness analysis

BACKGROUND

We investigated incremental cost of nosocomial pneumonia (NP) from the perspective of a hospital and health insurance funds.

PATIENTS AND METHODS

The incremental cost was determined by calculating total costs for pneumonia patients and controls using prospective and retrospective matched-pairs analysis with 29 and 37 matched pairs, respectively.

RESULTS

Compared to controls, patients who developed pneumonia had to be on artificial ventilation 5 days longer, needed markedly more intensive care with 6.55 additional days in intensive care. Excess cost per pneumonia patient amounted to DM 14,606 (95% CI: DM 5,285-23,927) from the hospital's perspective and to DM 7,988 (95% CI: DM 5,281-10,894) according to statutory insurance charges. According to the retrospective anaLysis carried out on the neurosurgical and neurological intensive care wards, pneumonia patients were ventiLated 5 days longer than patients without pneumonia, needed more intensive care over 30 days and had an additional 14.03 days of intensive care and 10.14 more days in hospital. Excess cost per patient was DM 29,610 (95% CI: DM 23,054-36,174) from the hospitals perspective and DM 18,000 (95% CI: 14,885-21,020) according to the statutory insurance criteria.

CONCLUSION

The study gives insight into the structure of incremental cost caused by NP and shows that based on a conservative cost calculation the incremental cost per NP patient is higher for the hospital than for health insurance funds which indicates a significant financial deficit for the hospital. Antibiotics and microbiology together only contribute 6.8% to incremental cost. Therefore in a cost saving initiative their close relationship to length of hospitalization must be considered.

Influence of an infectious disease consulting service on quality and costs of antibiotic prescriptions in a university hospital

An infectious disease consulting service was set up at a large tertiary university hospital in 1996 to evaluate and to improve antibiotic prescription patterns. Treatment guidelines for the most common bacterial infections were implemented. On daily ward rounds antibiotic therapies without evidence of an infectious disease were stopped and inappropriate regimens were changed by an infectious disease specialist. During a 6-month prospective intervention period, 3,528 patients were studied on 13 wards of the department of internal medicine; 513 of these patients (14.5%) received antibiotic therapy. These treatment courses were evaluated as adequate in 394 cases (76.8%) and incorrect in 119 cases (23.2%). Inadequate antibiotic substances were chosen in 72 out of 119 cases (60.5%) and there was no indication for treatment in 38 out of 119 cases (32%). Pathogen-specific therapies were inadequate significantly more often than empirical antimicrobial therapies (p < 0.001). In addition, the duration of the perioperative prophylaxis could be limited to 1 d. Comparing the intervention period with a 3-month control interval without an infectious disease consulting service, a total of 31,510 Euro (including the costs for the infectious disease specialist) could be saved. No increase in infection-related mortality or length of stay was observed. These data show that an infectious disease consulting service optimizes antibiotic usage, and is cost-effective as a result of a significant cost reduction in hospitals, while not interfering with the quality of medical care.

The organization of infection control in Germany

The authors outline the organization of infection control in Germany, focusing on official regulations, the training of infection control staff, and functions of the infection control committee and the availability of guidelines.

A new and rapid method for monitoring the new oxazolidinone antibiotic linezolid in serum and urine by high performance liquid chromatography-integrated sample preparation

A sensitive and rapid HPLC-assay for determining the new oxazolidinone antibiotic linezolid in serum and urine is described. HPLC-integrated sample preparation permits the direct injection of serum and urine samples without any pre-treatment. The in-line extraction technique is realized by switching automatically from the extraction column to the analytical column. After the matrix has passed the extraction column the retained analyte will be quantitatively transferred to the analytical column where separation by isocratic HPLC will be performed. Linezolid is detected according to its absorption maximum at 260 nm. The quantification limits are estimated to be 0.3 and 0.5 microg/ml in serum and urine samples, respectively. The described procedure allows sample clean-up and determination of the antibiotic within 20 min, thereby facilitating drug-monitoring in clinical routine.

Rapid antibiotic drug monitoring: meropenem and ceftazidime determination in serum and bronchial secretions by high-performance liquid chromatography-integrated sample preparation

A sensitive and rapid HPLC assay for the determination of the beta-lactam antibiotics ceftazidime and meropenem in serum and bronchial secretions is described. HPLC-integrated sample preparation allows direct injection of serum samples without any pretreatment. Sputum samples need only a simple homogenisation and volume measurement but no liquefying reagents are necessary. The inline extraction technique is realized by automatically switching from the extraction column to the analytical column. After the matrix passed the extraction column, the retained analyte is quantitatively transferred to the analytical column where separation by isocratic HPLC is performed. Ceftazidime and meropenem are detected according to their absorption maxima at 258 and 296 nm, respectively. The detection limit of both antibiotics is estimated to be better than 0.5 microg/ml in serum as well as in sputum samples. The described procedure allows determination of the antibiotics within 30-45 min, thereby facilitating drug monitoring in clinical routine.

Efficacy of moxifloxacin, trovafloxacin, clinafloxacin and levofloxacin against intracellular Legionella pneumophila

This study compares the in vitro activity of novel fluoroquinolones against clinical Legionella pneumophila isolates. We determined both the MICs and intracellular efficacy of moxifloxacin, trovafloxacin, clinafloxacin and levofloxacin in the Mono Mac 6 infection model. Six legionella strains were tested and all proved highly susceptible to the fluoroquinolones. Clinafloxacin and trovafloxacin were found to have the lowest MICs (0.004 mg/L) followed by levofloxacin and moxifloxacin (0.015-0.03 mg/L). In the Mono Mac 6 infection model, inhibition of L. pneumophila was achieved at concentrations four times below the respective in vitro MICs. Concentrations as low as 0.015 mg/L of moxifloxacin and levofloxacin, 0.004 mg/L of trovafloxacin and 0.002 mg/L of clinafloxacin markedly decreased viable intracellular bacterial counts. These data strongly support further clinical evaluation of new fluoroquinolones for empirical treatment of lower respiratory tract infection including atypical pneumonia caused by L. pneumophila.

In vitro susceptibility to everninomycin of gram-positive nosocomial pathogens isolated from intensive care units in Germany

BACKGROUND

Gram-positive bacteria are increasingly found to be causative pathogens in nosocomial infections, and the occurrence of vancomycin resistance in enterococci as well as staphylococci has prompted the investigation of alternative antimicrobial agents active against these strains. Everninomycin, a new oligosaccharide antibiotic, has excellent in vitro activity against gram-positive bacteria, including those resistant to vancomycin. However, avilamycin, a related compound, has been used in Europe as a growth promoter in animal food for years and concern has been raised that cross-resistance in clinical isolates may arise.

METHODS

We studied a collection of 268 nosocomial gram-positive isolates from intensive care unit patients with nosocomial pneumonia, urinary tract infection and sepsis, using standard in vitro susceptibility testing.

RESULTS

It could be shown that all species tested were exquisitely sensitive to everninomycin (MIC(90) of 0.38 microg/ml for Staphylococcus aureus, 0.5 microg/ml for enterococci and 0.75 microg/ml for coagulase-negative staphylococci). Furthermore, no difference could be observed between methicillin-resistant and methicillin-sensitive S. aureus or between Enterococcus faecium and Enterococcus faecalis.

CONCLUSIONS

These results suggest that everninomycin is a promising antibiotic for the treatment of nosocomial infections in intensive care unit patients and that the use of a related substance as an additive in animal food has not yet promoted resistance in clinical isolates.

Methicillin-resistant Staphylococcus aureus in a teaching hospital: investigation of nosocomial transmission using a matched case-control study

In early 1996 a hospital-wide methicillin-resistant Staphylococcus aureus (MRSA) epidemic was recognized in a 900-bed university hospital. In order to investigate hospital-specific transmission routes, a case-control study was carried out. Cases and controls were matched for age (+/- 10 years), sex, admission date (+/- 10 days) and clinical department on admission. Data on potential risk factors, were retrieved by chart review. Between June 1996 and February 1997, 67 patients with hospital-acquired MRSA were identified. Molecular typing showed that 85% of the cases carried an indistinguishable strain. The average time at risk for cases and controls was 17.3 and 23.7 days, respectively (P= 0.01). Seventeen patients (25.4%) developed infection. Conditional multivariate regression analysis showed that intensity of care (P= 0.002), number of transfers (P= 0.019), and fluoroquinolone therapy (P= 0.025) were independently associated with acquisition of MRSA. Intensity of care can be considered as a surrogate marker for a number of manipulations which represent the main risk factors for MRSA transmission. Frequent transfers within the hospital hinder, not only the epidemiological analyses, but also efforts to bring an outbreak under control. Our findings give epidemiological support to recent molecular studies which suggest that fluoroquinolone use may increase the transmissibility of MRSA in hospitals.

The effect of azithromycin on intracellular Legionella pneumophila in the Mono Mac 6 cell line at serum concentrations attainable in vivo

We investigated the antimicrobial efficacy of clinically meaningful, low concentrations of azithromycin against intracellular growth of two clinical isolates of Legionella pneumophila. The mature monocytic cell line Mono Mac 6 was used as a model to investigate the effects of antimicrobial agents on L. pneumophila. Extracellular susceptibility was determined by microdilution susceptibility testing in BYEalpha broth after 48 h of incubation. Mono Mac 6 cells infected with L. pneumophila were incubated with various concentrations of azithromycin. After 2 days of incubation, intracellular bacteria were released from the phagocytes and plated on to BCYEalpha agar. Addition of the intracellular-acting antibiotics azithromycin or ciprofloxacin at their MICs (0.5 and 0. 015 mg/L, respectively) resulted in a significant decrease in cfu, of up to approximately 1 log(10) after 48 h of incubation. In contrast, incubation of intraphagocytic L. pneumophila in the presence of antibiotics without intracellular activity (ceftizoxime, imipenem or amoxycillin-clavulanic acid) did not have any effect. Azithromycin inhibited intracellular replication at concentrations as low as 0.125 mg/L, approximately one-quarter of the extracellular MIC. The Mono Mac 6 cell line is a useful infection model for investigating the intracellular activity of antimicrobial agents in vitro. In accordance with clinical data and animal experiments, azithromycin and ciprofloxacin inhibited the intraphagocytic replication of L. pneumophila. In particular, azithromycin killed ingested legionellae in vitro at concentrations below the peak serum concentrations and below the MIC.