1,721,000 research outputs found
On-site application of the exposure chamber method in hospitals to control the airborne microbial recontamination of sterilized products during shelf life
No full textAssociation between lifetime exposure to environmental lead and student performance assessed by the first PISA survey
No full textAssociation between lifetime exposure to environmental lead and student performance assessed by the first PISA survey
No full textDetermination of the Efficacy of Sterile Barrier Systems Against Microbial Challenges During Transport and Storage
No full textOBJECTIVE. The sterility assurance level of 10(-6) is an established standard that defines the quality of sterile products. The aim of the present study was to develop a method that correlated the results from microbial-barrier testing of flexible sterile barrier systems with the estimated microbial challenge that the package encounters during storage and transport. METHODS. The effectiveness of microbial-barrier packaging was determined by the use of an exposure chamber test with 20 periodic atmospheric pressure changes of 50 and 70 hPa. Flexible peel pouches were used as sterile barrier systems. The logarithmic reduction value of a sterile barrier system was calculated on the basis of the experimental results and compared with the logarithmic reduction value required for the microbial challenges to maintain sterility during transport and storage. RESULTS. For pouches made of paper and plastic-film material, a logarithmic reduction value of 5.4 was obtained on the basis of 30 of 99 plates becoming nonsterile after being exposed to a 50 hPa difference in periodic atmospheric pressure changes. For pouches made of paper and plastic-film material, a logarithmic reduction value of 5.2 was obtained on the basis of 48 of 100 plates becoming nonsterile after being exposed to a 70 hPa difference in atmospheric pressure. For pouches made of nonwoven and plastic-film material, logarithmic reduction values of 6.38 (ie, 3 of 99 plates became nonsterile after being exposed to a 50 hPa pressure difference) and 6.07 (ie, 3 of the 99 plates became nonsterile after being exposed to a 70 hPa pressure difference) were obtained. Calculating an expected microbial challenge during transport and storage that requires barrier properties corresponding to a logarithmic reduction value of 5.83 and taking the sterility assurance level into account, we found that only the nonwoven pouches fulfilled the European standard EN 556-1. CONCLUSIONS. Using the data obtained in a microbial exposure test with a specified flow rate of a bacterial aerosol, we found that the effectiveness of the sterile barrier system against the actual microbial challenge can be examined and evaluated at the sterility assurance level of 10(-6)
Assessment of the sterility of wrapped terminally sterilized medical devices at the sterility assurance level of 1:1000000
No full textAssessment of the sterility of wrapped terminally sterilized medical devices at the sterility assurance level of 1:1000000
No full textA new method for testing the effectiveness of the microbial barrier properties of packaging materials for sterile products
No full textThe aim of our study was to develop a practical test for assessing the effectiveness of the microbial barrier of packaging materials for sterile products. The suitability of the test was verified in the exemplary case of double-wrapped sterilized trays. During testing, the bacterial count of the ambient air was 35 and 440 colony-forming units/cubic metre. The test is based on the co-sterilization in the sterile packing of petri dishes containing CASO agar, which at the end of the test were investigated for re-contamination. The petri dishes covered the sterilizing sieves as completely as possible. After sterilization, the packaging was loaded 300 to 900 times at a pressure of 1 kg (5x/min). This was followed by incubation for 48 hours at 37 degreesC, and evaluation (No. of colonies). The ability of the agar to culture colonies of bacteria was preserved unchanged for a period of at least 3 weeks after sterilization. For double-wrapped trays it was shown that re-contamination increases with intensity of mechanical loading and the atmospheric bacterial count. Since the package was breached only for the analysis, confounding factors due to removal of contents for examination, were effectively excluded. This test procedure is characterised by simplicity in handling and high specificity. As a final pack test it effectively closes a gap in the quality assurance chain for sterile materials
Test to determine sterile integrity of wrapped medical products at a probability of recontamination of 1 : 1,000,000
No full textObjective. We developed a microbiological test to detect the penetration of airborne microorganisms through the packaging of medical products after sterilization, to meet the requirements of European standard EN 556. We applied this test method to transparent pouches. Design. The microbial-barrier properties of the transparent pouches were determined using the microbial challenge test, in which the package was placed inside an exposure chamber and exposed to a defined aerosol of Saccharomyces cerevisiae. The atmospheric pressure in the chamber was periodically reduced by 0-75 millibars, to simulate weather-dependent pressure changes. Thermoresistant petri dishes filled with nutrient agar were integrated into the transparent pouches before sterilization. The packages were incubated after exposure. They were then opened and examined for colony growth. Results. The number of recontaminated packages per test group () depended on the microbial bioload (defined as the number n = 50 of colony-forming units per plate) to which the packages were exposed and on the size and number of decreases in atmospheric pressure. Results of multiple regression analysis showed a significant increase in the number of recontaminated packages in correlation with the product of the values for microbial bioload and the size and number of decreases in atmospheric pressure. When we analyzed the probability of recontamination of wrapped medical devices after 2 reductions in atmospheric pressure ( 30 millibars each) and with a surface microbial load of 10 colony-forming units per 64 cm(2), we estimated that the frequency of recontamination was 1 : 100,000. Conclusion. Multiple regression analysis showed that the proposed microbial challenge test is suitable to determine the probability of package recontamination at the 1 : 1,000,000 level
Preliminary results for a new final package test to assess the quality of sterile package systems
No full textOBJECTIVES: To develop a microbial test method to ascertain the passage of airborne bacteria through the medical device packaging system after sterilization, and to apply this test method to flexible packages under mechanical pressure changes. METHODS: Petri dishes filled with nutrient agar were integrated into the packaging unit prior to sterilization. We examined paper packaging consisting of 1 (single-paper packaging [P]), 2 (double-paper packaging [PP] and textile and paper double packaging [TP]), and 3 (double packaging with transport packaging [TPP]) layers. After sterilization, the test packages were pressed five times per minute for 1 or 3 hours by a mechanical device weighing 1 kg. This exposure took place in rooms with an average airborne bacterial count of 35 (room 1) or 440 (room 2) CFU/m(3). The packaging was opened following culture at 37degreesC for 48 hours to determine the number of colonies formed. RESULTS: The proportion of contaminated packages rose with the duration of mechanical stress and increased airborne bacteria concentration. Thus, mechanical pressure change for 3 hours resulted in the contamination of 60% (P), 15% (PP), 0% (TP), and 0% (TPP) of the packages in room 1, whereas 100% (P), 65% (PP), 73% (TP), and 0% (TPP) of the packages in room 2 were contaminated. CONCLUSIONS: This test method allows sterile packaging systems to be tested for contamination under practical conditions without extensive laboratory preparation. Contamination as a result of laboratory errors can be ruled out almost certainly
Measurement of the microbial barrier effectiveness of sterilization containers in terms of the log reduction value for prevention of nosocomial infections
No full textBackground: The microbial barrier properties of 216 sterilization containers of 4 central sterile supply departments of different hospitals were measured using a microbial challenge test. Methods: Uncovered thermoresistant plates filled with Sabouraud agar were placed on the base of the containers prior to sterilization. After sterilization. the containers were exposed to a defined microbial aerosol and periodic atmospheric pressure reductions of 10 to 70 hPa in an exposure chamber. After exposure and incubation of the entire containers. colony growth was registered as colony forming units (CFU) on the plates and the control plates to calculate the barrier effectiveness in terms of the logarithmic reduction value (LRV). Results: Two out of 11 standard containers with paper filters and 9 out of 79 containers with textile filters showed no growth on the plates. The mean colony numbers were 222 CFU/600 cm(2) (standard container with paper filter) and 209 CFU/600 cm(2) (container with textile filter). Fourteen out of 15 containers with permanent plastic filters did not show any growth on the plates. No recontamination was observed in 18 of 111 half-size containers. The mean colony numbers of the recontaminated half-size containers were 110 (paper filter) and 34 CFU per 300 cm2 (textile filter). The LRVs of the full-size and half-size containers tested ranged between 1.08 and > 4. Conclusion: As shown in this study the microbial barrier effectiveness of sterilization containers in the routine clinical setting can be tested with a quantitative microbial challenge test at intervals of 1 year to eliminate defect or ineffective containers as potential causal factors for nosocomial infections. An LRV of > 4 Should be envisaged as the target assurance level
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