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- Alsved, Malin, et al.
(författare)
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Airborne bacteria in hospital operating rooms during ongoing surgery
- 2018
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Konferensbidrag (refereegranskat)abstract
- IntroductionPost-operative infections obtained from open-wound surgeries constitute an unnecessary load on both healthcare and affected patients. It is well established that increased air cleanliness reduces the number of post-operative infections. Therefore, the ventilation system is important in order to reduce the number of infectious particles in the air during surgery. Ventilation with high airflow, as in operating rooms, consumes a high amount of energy and it is thus desirable to find energy efficient solutions. ObjectivesThe purpose of this work was to evaluate air quality, energy efficiency and working environment comfort for three different ventilation techniques in operating rooms. MethodThe newly developed ventilation system temperature controlled airflow (TcAF) was compared with the conventionally used turbulent mixed airflow (TMA) and laminar airflow (LAF). In total, 750 air sample measurements were performed during 45 orthopaedic operations: 15 for each type of ventilation system [1]. The concentration of colony forming units (CFU)/m3 was measured at three locations in the rooms: close to the wound (<0.5 m), at the instrument table and peripherally in the room. The working environment comfort was evaluated in a questionnaire.ResultsOur study shows that both LAF and TcAF maintains CFU concentrations in the air during ongoing surgery significantly below 10 CFU/m3 at the wound and at the instrument table, and for TcAF also in the periphery of the room, see Figure 1. The median CFU concentration in TMA was at or above 10 CFU/m3 at all locations. TcAF used less than half the airflow to that of LAF, resulting in a 28% reduction in energy consumption. The working environment comfort was perceived less noisy and having less draft in the TcAF than the LAF ventilation.SummaryBoth the LAF and TcAF ventilation maintain high air cleanliness with low CFU concentrations throughout the operation. TMA is less efficient in removing bacteria from the air close to the patient.
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- Alsved, Malin, et al.
(författare)
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Effect of Aerosolization and Drying on the Viability of Pseudomonas syringae Cells
- 2018
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Airborne dispersal of microorganisms influences their biogeography, gene flow, atmospheric processes, human health and transmission of pathogens that affect humans, plants and animals. The extent of their impact depends essentially on cell-survival rates during the process of aerosolization. A central factor for cell-survival is water availability prior to and upon aerosolization. Also, the ability of cells to successfully cope with stress induced by drying determines their chances of survival. In this study, we used the ice-nucleation active, plant pathogenic Pseudomonas syringae strain R10.79 as a model organism to investigate the effect of drying on cell survival. Two forms of drying were simulated: drying of cells in small droplets aerosolized from a wet environment by bubble bursting and drying of cells in large droplets deposited on a surface. For drying of cells both in aerosol and surface droplets, the relative humidity (RH) was varied in the range between 10 and 90%. The fraction of surviving cells was determined by live/dead staining followed by flow cytometry. We also evaluated the effect of salt concentration in the water droplets on the survival of drying cells by varying the ionic strength between 0 and 700 mM using NaCl and sea salt. For both aerosol and surface drying, cell survival increased with decreasing RH (p < 0.01), and for surface drying, survival was correlated with increasing salt concentration (p < 0.001). Imaging cells with TEM showed shrunk cytoplasm and cell wall damage for a large fraction of aerosolized cells. Ultimately, we observed a 10-fold higher fraction of surviving cells when dried as aerosol compared to when dried on a surface. We conclude that the conditions, under which cells dry, significantly affect their survival and thus their success to spread through the atmosphere and colonize new environments as well as their ability to affect atmospheric processes.
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