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ABSTRACT: This study assessed the effectiveness of a fully automated surveillance system for the detection of healthcare-associated infections (HCAIs) in intensive care units. Manual ward surveillance (MS) and electronic surveillance (ES) were performed for two intensive care units of the Vienna General Hospital. All patients admitted for a period longer than 48 h between 13 November 2006 and 7 February 2007 were evaluated according to HELICS-defined rules for HCAI. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and personnel time spent per surveillance type were calculated. Ninety-three patient admissions were observed, whereby 30 HCAI episodes were taken as a reference standard. Results with MS versus ES were: sensitivity 40% versus 87%, specificity 94% versus 99%, PPV 71% versus 96%, NPV 80% versus 95%, and time spent per surveillance type 82.5 h versus 12.5 h. In conclusion, ES was found to be more effective than MS while consuming fewer personnel resources.
Journal of the American Medical Informatics Association 08/2012; · 3.61 Impact Factor
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ABSTRACT: We report on intelligent information technology tools that produce fully-automated surveillance reports of high precision for 12 intensive care units (ICUs) without relevant time expenditure of infection control or ICU staff. This is accomplished by MONI-ICU, a computerized system for automated identification and continuous monitoring of ICU-associated infections, which makes surveillance data readily accessible and presents them in easily perceptible reporting format.
Studies in health technology and informatics 01/2012; 180:1165-7.
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ABSTRACT: Central venous catheters (CVCs) play an essential role in the care of the critically ill, but their use comes at the risk of infection. By using fuzzy set theory and logic to model clinical linguistic CVC-related infection criteria, clinical detection systems can detect borderline infections where not all infection parameters have been (fully) met, also called fuzzy results. In this paper we analyzed the clinical use of these results. We used a fuzzy-logic-based computerized infection control system for the monitoring of healthcare-associated infections to uncover fuzzy results and periods, after which we classified them, and used these classifications together with knowledge of prior CVC-related infection episodes in temporal association rule mining. As a result, we uncovered several rules which can help with the early detection of re-occurring CVC-related infections.
Studies in health technology and informatics 01/2012; 180:579-83.
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ABSTRACT: Aspergillus spp are ubiquitous spore-forming fungi. Construction work, renovation, demolition, or excavation activities within a hospital or in surrounding areas increase the risk for aspergillus infection in susceptible patients and are the main cause of nosocomial aspergillus outbreaks.
We investigated the efficacy of infection control measures on the frequency of fungal infection among hemato-oncologic patients undergoing stem cell transplantation during excavation and construction work of an adjacent hospital building. Clinical isolates from these patients obtained before and during the excavation and construction period were analyzed. Preventive measures consisted in the implementation of a multibarrier concept to protect these patients from fungal infection.
There was no record of any clinical isolate of Aspergillus spp in the observation period before the beginning of the groundwork. However, 3 clinically significant isolates of Aspergillus spp were detected in respiratory tract specimen of 2 patients after the beginning of excavation and demolition work, which were found to be community acquired.
Although our data cannot demonstrate the efficacy of infection control measures during construction work, it can be concluded that excavation work close to immunocompromised patients is safe if a bundle of preventive measures is implemented before groundwork.
American journal of infection control 06/2011; 39(9):746-51. · 3.01 Impact Factor
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ABSTRACT: According to manufacturers information, the STERRAD 100NX sterilizer-a low temperature H(2)O(2) gas plasma sterilizer-can adequately process single channel stainless steel lumens with an inside diameter of 0.7 mm or larger and a maximum length of 500 mm using standard cycle sterilizing conditions. The aim of this study was to qualify the performance of this H(2)O(2) gas plasma sterilizer under different experimental settings representing worst case conditions.
Inoculated carriers were placed at the midpoint position of specified lumens and then submitted to flex scope sterilizing conditions. To simulate insufficient cleaning or crystalline residues, we added organic and inorganic challenges to our inoculated carriers.
For experiments done with unchallenged carriers, quantitative analysis reached a log(10) reduction rate of ≥5.71, whereas qualitative results showed no growth in 24 out of 30 biologic indicators tested using flex scope half cycle conditions. Any additional kind of challenge significantly impaired the sterilization outcome.
The findings of our current study emphasize the importance of a thorough validated cleaning of medical devices as well as timing for cleaning and decontamination before being exposed to the H(2)O(2) sterilization process and, furthermore, the need for strict adherence to manufacturer's recommendations.
American journal of infection control 06/2011; 39(9):770-4. · 3.01 Impact Factor
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ABSTRACT: This study investigated the influence of the size of unidirectional ceiling distribution systems on counts of viable microorganisms recovered at defined sites in operating room (ORs) and on instrument tables during orthopedic surgery.
We compared bacterial sedimentation during 80 orthopedic surgeries. A total of 19 surgeries were performed in ORs with a large (518 cm × 380 cm) unidirectional ceiling distribution (colloquially known as laminar air flow [LAF]) ventilation system, 21 procedures in ORs with a small (380 cm × 120 cm) LAF system, and 40 procedures in ORs with no LAF system. Bacterial sedimentation was evaluated using both settle plates and nitrocellulose membranes.
Multivariate linear regression analysis revealed that the colony-forming unit count on nitrocellulose membranes positioned on the instrument table was significantly associated only with the size of the unidirectional LAF distribution system (P < .001), not with the duration of the surgical intervention (P = .753) or with the number of persons present during the surgical intervention (P = .291).
Our findings indicate that simply having an LAF ventilation system in place will not provide bacteria-free conditions at the surgical site and on the instrument table. In view of the limited number of procedures studied, our findings require confirmation and further investigations on the ideal, but affordable, size of LAF ventilation systems.
American journal of infection control 04/2011; 39(7):e25-9. · 3.01 Impact Factor
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ABSTRACT: Background: Bacterial contamination of anesthesia breathing machines and their potential hazard for pulmonary infection and cross-infection among anesthetized patients has been an infection control issue since the 1950s. Disposable equipment and bacterial filters have been introduced to minimize this risk. However, the machines' internal breathing-circuit-system has been considered to be free of micro-organisms without providing adequate data supporting this view. The aim of the study was to investigate if any micro-organisms can be yielded from used internal machines' breathing-circuit-system. Based on such results objective reprocessing intervals could be defined.Methods: The internal parts of 40 anesthesia machines' breathing-circuit-system were investigated. Chi-square test and logistic regression analysis were performed. An on-site process observation of the re-processing sequence was conducted.Results: Bacterial growth was found in 17 of 40 machines (43%). No significant difference was ascertained between the contamination and the processing intervals. The most common contaminants retrieved were coagulase negative Staphylococci, aerobe spore forming bacteria and Micrococcus species. In one breathing-circuit-system, Escherichia coli, and in one further Staphylococcus aureus were yielded.Conclusion: Considering the availability of bacterial filters installed on the outlet of the breathing-circuit-systems, the type of bacteria retrieved and the on-site process observation, we conclude that the contamination found is best explained by a lack of adherence to hygienic measures during and after re-processing of the internal breathing-circuit-system. These results support an extension of the re-processing interval of the anesthesia apparatus longer than the manufacturer's recommendation of one week. However, the importance of adherence to standard hygienic measures during re-processing needs to be emphasized.
GMS Krankenhaushygiene interdisziplinär. 01/2011; 6(1):Doc14.
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ABSTRACT: Bacteremias caused by Staphylococcus aureus and Escherichia coli are among the most common bloodstream infections (BSIs) in adults. The aim of the study was to investigate risk factors for infection and clinical outcomes of bacteremias caused by S aureus or E coli.
We conducted a 1-year matched prospective cohort study including 150 patients with BSI caused by susceptible or resistant S aureus or E coli and 300 controls without BSI caused by these organisms.
Of the 150 episodes of bacteremia, 37% were caused by S aureus (including 5 cases of methicillin-resistant S aureus [MRSA]) and 63% were caused by E coli (including 9 cases of extended-spectrum beta lactamase [ESBL]-producing E coli). We identified 4 independent risk factors for acquisition of S aureus bacteremia (emergency, peripheral or central vascular catheter, renal disease) and 6 risk factors for E coli bacteremia (emergency, peripheral or central vascular catheter, malignancy, cytoreductive or immunosuppressive therapy). Both types of bacteremia were associated with an increased length of hospital stay compared with controls. We observed a 5-fold increase in the 30-day mortality rate for bacteremias due to S aureus, and a 2-fold increase in BSI caused by E coli. The in-hospital mortality rate was increased by 6-fold for S aureus and by 3-fold for E coli.
Longer hospitalization periods and increased mortality of bacteremias caused by S aureus or E coli, irrespective of susceptibility, implicate controlling for risk factors at an early stage.
American journal of infection control 12/2010; 38(10):839-45. · 3.01 Impact Factor
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ABSTRACT: Sterrad sterilizers have been developed for the sterilization of thermolabile materials. The aim of the present study was to challenge the efficacy of this low-temperature hydrogen peroxide-based sterilization system with different carrier materials and wrappings under experimental "clean" and "dirty" conditions.
We tested the sporocidal effect of the Sterrad 100NX sterilizer (Advanced Sterilization Products, Irvine, CA) on the carrier materials titanium, polyethylene, and polyurethane with single versus 3 wrappings of inoculated carriers. To simulate insufficient cleaning or crystalline residues, carriers were charged with spore inocula containing organic and inorganic burdens.
Our qualitative results show that irrespective of the number of wrappings in the "clean" condition, sterilization by the Sterrad 100NX was equally effective on all 3 carrier materials, reaching a log-10 reduction rate of ≥ 6 under standard half-cycle conditions. Any additional organic or inorganic challenge significantly impaired the sterilization outcome.
Results of our current study emphasize the utmost importance of thorough and reliable cleaning of medical devices before being exposed to a subsequent hydrogen peroxide sterilization process. Any institution using this sterilization technology should have a well-established and validated cleaning process and enforce a rigorous quality assurance program for all steps of the presterilization processing of medical devices.
American journal of infection control 12/2010; 38(10):806-10. · 3.01 Impact Factor
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ABSTRACT: The aim of this study was to investigate the decontamination capacity of 4 different types of cleaning cloths (microfiber cleaning cloth, cotton cloth, sponge cloth, and disposable paper towels) commonly used in hospital in their ability to reduce microbial loads from a surface used dry or wet in new condition. All of the cloths except disposable paper towels were also compared after 10 and 20 times of reprocessing, respectively, at 90 degrees C for 5 minutes in a washing machine.
Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 8739) were used as test organisms. Test organisms were then added to a test soil (6% bovine serum albumin and 0.6% sheep erythrocytes) resulting in a controlled concentration of 5 x 10(7) colony-forming units per milliliter in the final test suspension. Standardized tiles measuring 5 x 5 cm were used as test surface.
Microfiber cloths showed the best results when being used in new condition. However, after multiple reprocessing, cotton cloth showed the best overall efficacy.
We therefore suggest that the choice of the cleaning utilities should be based on their decontamination efficacy after several reprocessings and recommend the establishment of strict and well-defined cleaning and disinfection protocols.
American journal of infection control 05/2010; 38(4):289-92. · 3.01 Impact Factor
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ABSTRACT: Surveillance of clinical entities such as healthcare-associated infections (HCAI) by conventional techniques is a time-consuming task for highly trained experts. Such are neither available nor affordable in sufficient numbers on a permanent basis. Nevertheless, expert surveillance is a key parameter for good clinical practice, especially in intensive care medicine. MONI-ICU (monitoring of nosocomial infections in intensive care units) has been developed methodically and practically in a stepwise manner over the last 20 years and is now a reliable tool for clinical experts. It provides an almost real-time view of clinical indicators for HCAI--at the cost of almost no additional time on the part of surveillance staff or clinicians. We describe the use of this system in clinical routine and compare the results generated automatically by MONI-ICU with those generated in parallel by trained surveillance staff using patient chart reviews and other available information ("gold standard"). A total of 99 ICU patient admissions representing 1007 patient days were analyzed. MONI-ICU identified correctly the presence of an HCAI condition in 28/31 cases (sensitivity, 90.3%) and their absence in 68/68 of the non-HCAI cases (specificity, 100%), the latter meaning that MONI-ICU produced no "false alarms". The time taken for conventional surveillance at the 52 ward visits was 82.5 hours. MONI-ICU analysis of the same patient cases, including careful review of the generated results required only 12.5 hours (15.2%).
Studies in health technology and informatics 01/2010; 160(Pt 1):432-6.
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ABSTRACT: The outcome of patients with bacteraemia is influenced by the initial selection of adequate antimicrobial therapy. The objective of our study was to clarify the influence of different crude data correction methods on a) microbial spectrum and ranking of pathogens, and b) cumulative antimicrobial susceptibility pattern of blood culture isolates obtained from patients from intensive care units (ICUs) using a computer based tool, MONI.
Analysis of 13 ICUs over a period of 7 years yielded 1427 microorganisms from positive results. Three different data correction methods were applied. Raw data method (RDM): Data without further correction, including all positive blood culture results. Duplicate-free method (DFM): Correction of raw data for consecutive patient's results yielding same microorganism with similar antibiogram within a two-week period. Contaminant-free method (CFM): Bacteraemia caused by possible contaminants was only assumed as true bloodstream infection, if an organism of the same species was isolated from > 2 sets of blood cultures within 5 days.
Our study demonstrates that different approaches towards raw data correction - none (RDM), duplicate-free (DFM), and a contaminant-free method (CFM) - show different results in analysis of positive blood cultures. Regarding the spectrum of microorganisms, RDM and DFM yielded almost similar results in ranking of microorganisms, whereas using the CFM resulted in a clinically and epidemiologically more plausible spectrum.
For possible skin contaminants, the proportion of microorganisms in terms of number of episodes is most influenced by the CFM, followed by the DFM. However, with exception of fusidic acid for gram-positive organisms, none of the evaluated correction methods would have changed advice for empiric therapy on the selected ICUs.
BMC Medical Informatics and Decision Making 06/2009; 9:27. · 1.48 Impact Factor
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ABSTRACT: Nosocomial or hospital-acquired infections (NIs) are a frequent complication in hospitalized patients. The growing availability of computerized patient records in hospitals permits automated identification and extended monitoring for signs of NIs. A fuzzy- and knowledge-based system to identify and monitor NIs at intensive care units (ICUs) according to the European Surveillance System HELICS (NI definitions derived from the Centers of Disease Control and Prevention (CDC) criteria) was developed and put into operation at the Vienna General Hospital. This system, named Moni, for monitoring of nosocomial infections contains medical knowledge packages (MKPs) to identify and monitor various infections of the bloodstream, pneumonia, urinary tract infections, and central venous catheter-associated infections. The MKPs consist of medical logic modules (MLMs) in Arden syntax, a medical knowledge representation scheme, whose definition is part of the HL7 standards. These MLM packages together with the Arden software are well suited to be incorporated in medical information systems such as hospital information or intensive-care patient data management systems, or in web-based applications. In terms of method, Moni contains an extended data-to-symbol conversion with several layers of abstraction, until the top level defining NIs according to HELICS is reached. All included medical concepts such as "normal", "increased", "decreased", or similar ones are formally modeled by fuzzy sets, and fuzzy logic is used to process the interpretations of the clinically observed and measured patient data through an inference network. The currently implemented cockpit surveillance connects 96 ICU beds with Moni and offers the hospital's infection control department a hitherto unparalleled NI infection survey.
Studies in health technology and informatics 02/2009; 149:103-10.
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ABSTRACT: Sternal wound infections are a major complication after cardiac surgery in terms of morbidity and cost increase. To decrease the incidence of infection, we evaluated triclosan-coated sutures for the closure of the sternal incision, as it is known that most of the surgical site infections are related to the incision site.
From May to December 2005, a total of 479 patients underwent a cardiac surgical procedure. From those, 103 patients were closed with triclosan-coated suture material (cost per patient $30 [in United States dollars]), whereas the remaining 376 patients had their incision closed with noncoated sutures (cost per patient $21).
During the study period, 24 patients had superficial (n = 10) or deep (n = 14) sternal wound infections (cost per patient $11,200). All those patients were closed with conventional suture material. In the triclosan group, no wound infection or dehiscence was observed during hospital stay and follow-up visits.
Triclosan-coated sutures might be valuable in the reduction of sternal wound infections and avoid the suture being a risk factor for surgical site infections. The increased cost of the coated suture material has to be weighed against the enormous cost of sternal wound infections caused directly by the cost of care as well as indirectly through the loss of economic productivity.
The Annals of thoracic surgery 08/2007; 84(1):232-6. · 3.74 Impact Factor
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ABSTRACT: Consensus exists that early recognition of sternal wound infection is crucial to prevent involvement and destruction of the sternal bone, which prohibits secondary sternal closure and necessitates the use of muscle flaps for wound closure. Since November 2001 to September 2005, 125 patients received a VAC system after surgical debridement. Thirty-eight patients had a superficial infection (2A) and 87 patients had a deep infection (2B). From those, 59 patients underwent secondary sternal closure after VAC therapy, whereas 28 patients needed muscle flap closure. The time of diagnosis of sternal infection had great impact on the outcome. It was made on POD 10.6+/-8.3 in the 2A group, and on POD 13.2+/-11.1 in the 2B group. In the patients from Group 2A who had a recurrence of infection, the initial diagnosis of infection was made on POD 13.1+/-11.1. In patients where an SC was possible the time of diagnosis was on POD 11.1+/-6.6 whereas POD 17.7+/-16.2 in the MF group. The key to successful management of sternal wound infection is early recognition and aggressive treatment with reopening of the entire wound and sternum, which seems mandatory to achieve a low recurrence rate.
Interactive cardiovascular and thoracic surgery 05/2006; 5(2):145-8.
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ABSTRACT: No data or recommendations are available on feasibility of surface disinfection of blood bags, but some circumstances can make such procedures inevitable. Impact of immersion of blood bags in 70% ethanol for 30min was investigated with respect to alcohol penetration and changes of hemolysis parameters in the product, and bag material changes influencing material stability and composition. After immersion ethanol concentration in blood bags was below detection limit. Hemolysis parameters did not differ between blood products that had been exposed to ethanol and a control group. Inner surface of the bag material was unchanged according to our infrared spectrometry results. Also endurance testing showed no altered results. We conclude that immersion of blood bags in 70% ethanol for surface disinfection is a safe procedure for the quality of the blood product and the bag material.
International journal of surgery (London, England) 02/2006; 4(2):118-21.
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ABSTRACT: Most of the knowledge on Mycoplasma pneumoniae encephalitis in children is based on case reports or small case series. The aim of this study was to assess the important features of the disease by a systematic review of previously published cases. Overall, 58 cases (22 female, 36 male; median age 10 years, range: 2-17 years), derived from 38 reports, were reviewed. Forty-five patients (76%) had flulike or respiratory symptoms prior to the onset of neurologic disease, and 23 patients (40%) presented with pulmonary infiltrates. Cerebrospinal fluid (CSF) pleocytosis (mostly mononuclear cells) and elevated cerebrospinal fluid protein counts were present in 34 (59%) and 21 (36%) patients, respectively. Cranial computed tomography (CT) or magnetic resonance imaging (MRI) abnormalities were seen in 18 (31%) and 17 (29%) patients, respectively, whereby various different presentations were observed. Forty-four patients (76%) received antimicrobial therapy active against mycoplasmas, most frequently erythromycin (n = 29) or minocycline (n = 6). Only in one patient, cure was directly attributed to antimicrobial therapy (with chloramphenicol) by the respective authors. Thirty-three patients (57%) recovered without sequelae, 20 patients (34%) had minor to major sequelae, and 5 patients (9%) died. A high cerebrospinal fluid cell count, cerebrospinal fluid protein elevation, and higher age were associated with an unfavorable outcome.
Journal of Child Neurology 12/2004; 19(11):865-71. · 1.75 Impact Factor
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ABSTRACT: To assess the influence of prophylactic selective bowel decontamination (SBD) on the spectrum of microbes causing bloodstream infection (BSI).
The microbes causing BSI in neutropenic patients of a hematologic ward (HW) and a bone marrow transplantation unit (BMTU), respectively, were compared by retrospective analysis of blood culture results from January 1996 to June 2003.
A 30-bed HW (no SBD) and a BMTU including a 7-bed normal care ward and an 8-bed intensive care unit (SBD used) of a 2,200-bed university teaching hospital.
The overall incidences of bacteremia in the HW and the BMTU were similar (72.6 vs 70.6 episodes per 1,000 admissions; P = .8). Two hundred twenty episodes of BSI were recorded in 164 neutropenic patients of the HW and 153 episodes in 127 neutropenic patients of the BMTU. Enterobacteriaceae (OR, 3.14; CI95, 1.67-5.97; P= .0002) and Streptococcus species (OR, 2.04; CI95, 1.14-3.70; P = .015) were observed more frequently in HW patients and coagulase-negative staphylococci more frequently in BMTU patients (OR, 0.15; CI95, 0.09-0.26; P < .00001). No statistically significant differences were found for gram-negative nonfermentative bacilli (P = .53), Staphylococcus aureus (P = .21), Enterococcus species (P = .48), anaerobic bacteria (P = .1), or fungi (P = .50).
SBD did not lead to a significant reduction in the incidence of bacteremia, but significant changes in microbes recovered from blood cultures were observed. SBD should be considered when empiric antimicrobial therapy is prescribed for suspected BSI.
Infection Control and Hospital Epidemiology 09/2004; 25(8):685-9. · 3.67 Impact Factor
