Browsing by Author "Dunkelberg, Hartmut"

The 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.

Copper in drinking water has been associated with non-Indian childhood cirrhosis (NICC), a form of liver cirrhosis in childhood. This epidemiological study examines the exposure of infants to increased copper concentrations through drinking water from public water supplies in southern Lower Saxony, Germany, and whether this dietary copper intake causes liver damage in early childhood. In total, water samples from 1674 households with infants were tested for copper. The mean copper concentration was 0.18 mg/L in the 1619 collected stagnation samples and 0.11 mg/L in the 1660 random daytime samples. There were notable regional differences in copper values. In 10.3% of all sampled households a copper value of 0.5 mg/L or more was found. These families were requested to additionally collect 2 composite samples. An increased level of copper in the drinking water with copper concentrations at or above 0.8 mg/L in the composite samples and a defined minimum ingestion of tap water was followed by a recommendation of a pediatric examination. Fourteen infants were examined by a pediatrician and of these 11 received a blood serum analysis. None of the examined infants showed any signs of liver malfunction. From the results of the study, no indication of a hazard due to copper pipes connected to public water supplies could be found. (C) 2003 Elsevier Science (USA). All rights reserved.

OBJECTIVE. 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).

Copper in drinking water has been associated with Non-Indian Childhood Cirrhosis (NICC), a form of early childhood liver cirrhosis. This epidemiological study examines the exposition of infants to increased copper concentrations through drinking water from public water supplies in Berlin, Germany, and if this dietary copper intake can cause liver damage in early childhood. In total, water samples from 2944 households with infants were tested for copper. Mean copper concentrations in the two different types of collected composite samples were 0.44 and 0.56 mg/l, respectively. Families having a copper concentration at or above 0.8 mg/l in one or both of the composite samples (29.9% of all sampled households) and a defined minimum ingestion of tap water of their infant were recommended to undergo a paediatric examination. Nearly every of the 541 recommended infants were examined by a local paediatrician and of these 183 received a blood serum-analysis, too. None of the infants had clear signs of a liver disease although a few serum parameters lay outside the accompanying reference range and abdominal ultrasound imaging gave slightly unusual results in five cases. Additionally, no signs of a negative health effect could be found in the statistical analysis of the serum parameters GOT, GPT, GGT, total bilirubin, serum. copper, or ceruloplasmin in relation to estimated daily and total copper intakes of the infants from tap water. No dose relation of serum parameters and estimated copper intakes could be established. From the results of the study, no confirmed indication of a liver malfunction in infants whose food had been prepared using tap water with an elevated copper concentration could be found and, therefore, no indication of a hazard due to copper pipes connected to public water supplies could be detected. (C) 2002 Elsevier Science B.V. All rights reserved.

The long-term toxicity of arsenic (As) as a result of exposure to contaminated drinking water might be modified by coinciding exposures to elements like selenium, antimony, or mercury. In this study the influence of tetravalent selenite, trivalent antimonite, and divalent mercury was investigated in vitro using cultured primary rat hepatocytes. The cell vitality was assessed in the 3-[4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide] (MTT), assay with concurrent exposures of the cells to up to 50 mu M sodium arsenite(III) and a potential modifier [50 mu M sodium(IV) selenite,10 mu M antimony(III) chloride, 25 mu M mercuric(II) chloride], which indicated an additive increase in the combined cytotoxicity. Sodium arsenite was tested for genotoxicity in the micronucleus test in a concentration range of 0.25 up to 7.5 mu M. In this range, the MTT conversion was at least 80%, indicating high cell viability. A dose-dependent induction of micronuclei was observed. The lowest concentration causing a significantly elevated frequency of micronuclei was 1 mu M As (p < 0.05). A significant influence (i.e., reduction of the combined genotoxicity as a result of the presence of a potential modifier) was only observed for 10 and 25 PM antimony chloride (p < 0.05, Fisher's exact test). The metabolic methylation of arsenite was not affected by concurrent incubation with any of the potential modifiers.

Aims: Greenhouse misting systems used for watering plants produce fine aerosols. They are a possible cause for bacterial infections. This study investigates the colonization of greenhouse misting systems with Legionella spp. and Pseudomonas spp. and evaluates a possible health hazard. Methods and Results: Between June and September 2003, a total of 80 water samples were collected in 20 different greenhouse systems in Germany, each tested on two different occasions. Each time, water was drawn at a central tap and at the outlet of spray nozzles. Sampled greenhouses were used to cultivate various plants and trees for commercial, recreational or scientific reasons, some of them in tropical conditions. Legionella spp. were detected in 10% of the systems (two systems), but only in low numbers. On the contrary, Pseudomonas spp. were recovered from 70% of the greenhouse watering systems (14 systems), occasionally at counts greater than 10 000 CFU per 100 ml. A random amplified polymorphic DNA polymerase chain reaction typing method was used to demonstrate that each colonized greenhouse had one or several individual strains of Legionella and Pseudomonas that could not be detected in any other system. Conclusions: This study demonstrates that aerosolizing greenhouse watering systems may be contaminated with Legionella or Pseudomonas which under certain circumstances could become a potential source of infection for workers and visitors. Significance and Impact of the Study: The study results indicate that greenhouse misting systems should be included in Legionella and Pseudomonas monitoring and control programs.

Lead has numerous acute and chronic adverse effects on human beings. This is especially true for infants and children. The main path of lead ingestion in children can be different according to housing and living situation. The intake of lead through drinking water is commonly due to metal corrosion. The users plumbing can be an important factor. In recent years, many lead pipes in Germany have been replaced by pipes made of an alternative material. The aim of this study is to assess the present state of drinking water contamination and the resulting exposure of infants to lead. For this purpose mothers of new-born babies were offered a free examination of their drinking water. After a written declaration of consent had been obtained and after the infant in question had reached an age of 3 months, a stagnation sample of cold tap-water after overnight stagnation together with a random daytime sample was obtained from the family. The collected samples were analysed by atomic absorption spectrometry for their lead concentration. In total, 1485 samples from households were collected. Of the 1434 stagnation samples, 3.1% had lead concentrations greater than 0.01 mg/l (recommended limit of the WHO) and 0.6% had concentrations above the limit of the German drinking water regulation (0.04 mg/l). The values for the 1474 random daytime samples were 2.1% above 0.01 mg/l and 0.2% greater than 0.04 mg/l, respectively. By region, the areas Bovenden, Friedland, Duderstadt, Northeim and Rosdorf were particularly affected. The highest measured concentrations of lead in the stagnation samples were 0.11 mg/l and 0.15 mg/l in the random daytime samples, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.

Background: The corrosion of drinking water pipe materials can release different elements into tap water. Especially important in this context is the heavy metal lead, which mainly leaches from the peripheral water distribution system. Lead is known to have numerous adverse effects especially to infants and children. Aim and Method: The aim of this project was to assess the present state of drinking water contamination with lead in Lower Saxony and to promote the replacement of lead pipes. For this purpose a project was initiated comprising three parts. Firstly, a free examination of drinking water was offered in cooperation with local public health departments for private households with young women and families with children living in buildings constructed before 1974. Participants were asked to collect a cold tap water sample in their household after nocturnal stagnation and to complete a questionnaire. The collected samples were analysed by atomic absorption spectrometry for their lead concentration. Secondly, data from local public health departments on results of lead measurements, especially in buildings for the public, were collected and analysed. Finally, a working group 'lead replacement' consisting of representatives of all relevant parties (e.g., tenant and landlord associations, handicraft, building and health administration) was initiated. Results: In the project in total 2901 tap water samples from households were collected between the years 2005 and 2007. Of these, 7.5% had lead concentrations exceeding 10 mu g/L (recommended limit of the World Health Organisation) and 3.3% had concentrations above the limit of the German drinking water ordinance (25 mu g/L). There were remarkable regional differences in the frequency of tap water contamination. Multi-family houses were more frequently affected than single and double family houses. Additional data were collected in a preceding study in southern Lower Saxony. Of the 1434 stagnation samples, 3.1% had lead concentrations greater than 10 mu g/L and 0.6% had concentrations above the former limit of the German drinking water regulations of 40 mu g/L.

Background: 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.

To examine the concordance of two metabolizing systems for. nse in genotoxocity testing with the micronucleas test, 15 naturally occurring substances (arecoline, the plant extract aristolochic acid, beta -asarone, benzyl acetate, coumarin, emodine, isatidine dihydrate, monocrotaline psoralen, reserpine, retrorsine safrole sanguinarine chloride, tannin and thiourea) weve tested for their genotoxicity ill the cytokinesis-block micronucleus test in vitro with human lymphocytes and in the presence and the absence of an exogenous metabolizing system fi om mt liver. S9-mix and the metabolically competent human hepatoma cell line Hep-G2. Arecoline, the plant extract aristolochic acid psoralen and tannin caused a significant increase in the number of micronuclei in human lymphocytes in the presence and the absence of an exogenous metabolising system from rat liver. S9-mix and the metabolically competent human hepatoma cell line Hep-G2. A significantly increase in the number of micronuclei with beta -asarone one coumarin, monocrotaline and retrorsine could be detected in the presence of S9-mix find the cell line Hep-G2. Benzyl acetate, emodine, isatidine dihydrate reserpine safrole, sanguinarine chloride and thiourea did nor reveal any micronucleus inducing activity in either human lymphocytes or in Hep-G2. In addition to the other Hep-GZ results in the literature this human hepatoma cell line could have a useful potential in the in vitro micronucleus test.

OBJECTIVES: 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.