Children’s residential exposure to selected allergens and microbial indicators: endotoxins and (1→3)-β-D-glucans

Objectives: The study was aimed at assessment of exposure to endotoxins, (1→3)-β-D-glucans and mite, cockroach, cat, dog allergens present in settled dust in premises of children as agents which may be significantly correlated with the occurrence of allergic symptoms and diseases in children. Materials and Methods: The study covered 50 homes of one- or two-year-old children in Poland. Samples of settled dust were taken from the floor and the child's bed. The levels of (1→3)-β-D-glucans (floor), endotoxins (floor) and allergens of mite, cat, dog and cockroach (floor and bed) were analyzed. Results: Average geometric concentrations (geometric standard deviation) of endotoxins, (1→3)-β-D-glucans, Der p1, Fel d1, Can f1 and Bla g1 in children homes were on the floor 42 166.0 EU/g (3.2), 20 478.4 ng/g (2.38), 93.9 ng/g (6.58), 119.8 ng/g (13.0), 288.9 ng/g (3.4), 0.72 U/g (4.4) and in their beds (only allergens) 597.8 ng/g (14.2), 54.1 ng/g (4.4), 158.6 ng/g (3.1) 0.6 U/g (2.9), respectively. When the floor was covered with the carpet, higher concentrations of endotoxins, (1→3)-β-D-glucans and allergens (each type) were found in the settled dust (p < 0.05). The trend was opposite in case of allergens (except dog) analyzed from bed dust and significantly higher concentrations were found in the rooms with smooth floor (p < 0.05). Conclusions: Among the analyzed factors only the type of floor significantly modified both the level of biological indicators and allergens. The results of this study could be the base for verifying a hypothesis that carpeting may have a protective role against high levels of cockroach, dog and cat allergens

Factors influencing biosafety level and lai among the staff of medical laboratories

Background: The aim of the study was to assess the biological risks of medical laboratory employees with particular focus on laboratory acquired infection (LAI), activities having the greatest risk, accidents with biological material, post exposure procedure, preventive measures and workers' knowledge about biological exposure. Materials and Methods: The study involved 9 laboratories. A questionnaire survey was attended by 123 employees and 9 heads of these units with the use of two questionnaires for laboratory workers and the managers. Results: 32.5% of the respondents (40 persons) had an accident at least once. Needlestick or a broken glass injury covered 18.7% respondents (23 persons), while splashing the skin, mucous membranes or conjunctivae related to 22.8% (28 persons). Among the employees who had an accident, only 45% of the respondents (18 persons) reported this to the manager. Microbes dominant in the biological material were known only to 57 respondents (46.3%), less than half could correctly give an example of a disease (57 persons, 46.3%). More than half of the respondents admitted that they do not know all of the possible routes of infection while working in the laboratory (68 persons, 55.3%). Conclusions: In the study population, a high incidence of accidents was observed, usually during blood sampling and transfer of biological material. Condition of the workers' equipment with personal protective measures and laboratory facilities in devices to reduce the risk of infection and procedures for handling the potentially infectious material should be considered as insufficient. Lack of basic knowledge of the employees about biohazards at workplaces was shown. Med Pr 2013;64(4):473–48

FACTORS INFLUENCING BIOSAFETY LEVEL AND LAI AMONG THE STAFF OF MEDICAL LABORATORIES

Background: The aim of the study was to assess the biological risks of medical laboratory employees with particular focus on laboratory acquired infection (LAI), activities having the greatest risk, accidents with biological material, post exposure procedure, preventive measures and workers' knowledge about biological exposure. Materials and Methods: The study involved 9 laboratories. A questionnaire survey was attended by 123 employees and 9 heads of these units with the use of two questionnaires for laboratory workers and the managers. Results: 32.5% of the respondents (40 persons) had an accident at least once. Needlestick or a broken glass injury covered 18.7% respondents (23 persons), while splashing the skin, mucous membranes or conjunctivae related to 22.8% (28 persons). Among the employees who had an accident, only 45% of the respondents (18 persons) reported this to the manager. Microbes dominant in the biological material were known only to 57 respondents (46.3%), less than half could correctly give an example of a disease (57 persons, 46.3%). More than half of the respondents admitted that they do not know all of the possible routes of infection while working in the laboratory (68 persons, 55.3%). Conclusions: In the study population, a high incidence of accidents was observed, usually during blood sampling and transfer of biological material. Condition of the workers' equipment with personal protective measures and laboratory facilities in devices to reduce the risk of infection and procedures for handling the potentially infectious material should be considered as insufficient. Lack of basic knowledge of the employees about biohazards at workplaces was shown. Med Pr 2013;64(4):473–48

Atomistic origin of nano-silver paracrystalline structure: molecular dynamics and x-ray diffraction studies

Classical molecular dynamics (MD) and x-ray diffraction (XRD) have been used to establish the origin of the paracrystalline structure of silver nanoparticles at the atomic scale. Models based on the face-centred cubic structure have been computer generated and their atomic arrangements have been optimized by the MD with the embedded-atom model (EAM) potential and its modified version (MEAM). The simulation results are compared with the experimental XRD data in reciprocal and real spaces, i.e. the structure factor and the pair distribution function. The applied approach returns the structural models, defined by the Cartesian coordinates of the constituent atoms. It has been found that most of the structural features of Ag nanoparticles are better reproduced by the MEAM. The presence of vacancy defects in the structure of the Ag nanoparticles has been considered and the average concentration of vacancies is estimated to be 3 at.%. The average nearest-neighbour Ag–Ag distances and the coordination numbers are determined and compared with the values predicted for the bulk Ag, demonstrating a different degree of structural disorder on the surface and in the core, compared to the bulk crystalline counterpart. It has been shown that the paracrystalline structure of the Ag nanoparticles has origin in the surface disorder and the disorder generated by the presence of the vacancy defects. Both sources lead to network distortion that propagates proportionally to the square root of the interatomic distances

The variability of bacterial aerosol in poultry houses depending on selected factors

Objectives: This study is aimed at evaluation of bacterial air contamination in intensive poultry breeding. The evaluation was based on the determined levels of bacterial concentrations and qualitative identification of isolated microorganisms. Materials and Methods: The study covered 5 poultry houses: two hatcheries and three hen houses with the litter bed system. The air was sampled in three measurement series in the central part of the investigated workplace at the height of about 1.5 m over the ground, using portable measuring sets consisting of a GilAir 5 (Sensidyne, USA) pump and a measuring head filled with a glass microfibre filter (Whatman, UK). For the quantitative and qualitative analysis of microorganisms were used appropriate microbiological media. Results: The total concentrations of airborne mesophilic bacteria inside the poultry breeding houses ranged from 4.74×10⁴ cfu/m³ to 1.89×10⁸ cfu/m³. For Gram-negative bacteria, the range comprised the values from 4.33×10² cfu/m³ to 4.29×10⁶ cfu/m³. The concentrations of the cocci of Enterococcus genus ranged from 1.53×10⁴ cfu/m³ to 1.09×10⁷ cfu/m³, whereas those of other Gram-positive bacteria from 3.78×10⁴ cfu/m³ to 6.65×10⁷ cfu/m³. The lowest concentrations of each group of the examined microorganisms were noted in the second measurement series when the air exchange in the breeding houses was over twice higher than in first and third measurement series because the mechanical ventilation was supported by natural ventilation (opened gates in the buildings). The lowest concentrations of total bacteria were obtained in those buildings where one-day old chickens were kept. Gram-positive bacteria of the genera: Staphylococcus, Enterococcus, Corynebacterium, Brevibacterium, Micrococcus, Cellulomonas, Bacillus, Aerococcus, and Gram-negative bacteria of the genera: Pseudomonas, Moraxella, Escherichia, Enterobacter, Klebsiella, Pasteurella, Pantoea were isolated. It was shown that for most of the investigated livestock premises the total bacteria concentrations exceeded the reference value of 1.0×10⁵ cfu/m³. Furthermore, pathogenic microorganisms which are a potential threat to human health (Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae ssp. ozaenae, Enterococcus faecalis, Enterococcus faecium) were found among the identified bacteria. Conclusions: The results indicate that the hygienic conditions of the working environment connected with litter bed system production of poultry are affected by changes of the efficiency of ventilation and create a direct health risk to employees. They should use personal protective measures to protect their respiratory tract, especially when the gates in the hen houses are closed

Children’s residential exposure to selected allergens and microbial indicators: endotoxins and (1→3)-β-D-glucans

Objectives: The study was aimed at assessment of exposure to endotoxins, (1→3)-β-D-glucans and mite, cockroach, cat, dog allergens present in settled dust in premises of children as agents which may be significantly correlated with the occurrence of allergic symptoms and diseases in children. Materials and Methods: The study covered 50 homes of one- or two-year-old children in Poland. Samples of settled dust were taken from the floor and the child's bed. The levels of (1→3)-β-D-glucans (floor), endotoxins (floor) and allergens of mite, cat, dog and cockroach (floor and bed) were analyzed. Results: Average geometric concentrations (geometric standard deviation) of endotoxins, (1→3)-β-D-glucans, Der p1, Fel d1, Can f1 and Bla g1 in children homes were on the floor 42 166.0 EU/g (3.2), 20 478.4 ng/g (2.38), 93.9 ng/g (6.58), 119.8 ng/g (13.0), 288.9 ng/g (3.4), 0.72 U/g (4.4) and in their beds (only allergens) 597.8 ng/g (14.2), 54.1 ng/g (4.4), 158.6 ng/g (3.1) 0.6 U/g (2.9), respectively. When the floor was covered with the carpet, higher concentrations of endotoxins, (1→3)-β-D-glucans and allergens (each type) were found in the settled dust (p < 0.05). The trend was opposite in case of allergens (except dog) analyzed from bed dust and significantly higher concentrations were found in the rooms with smooth floor (p < 0.05). Conclusions: Among the analyzed factors only the type of floor significantly modified both the level of biological indicators and allergens. The results of this study could be the base for verifying a hypothesis that carpeting may have a protective role against high levels of cockroach, dog and cat allergens