Estudio longitudinal y multicéntrico sobre bioseguridad ambiental en salas de ambiente controlado

Laburpena

ntroduction: There is no international consensus on the relevance of periodic monitoring of microorganisms in the air on surfaces of controlled environment rooms, except during construction works or outbreaks, nor on the appropriate thresholds of Environmental Parameters (EP) and Design Parameters (DP) to maintain the air and surfaces free of microorganisms. Obtaining adequate environmental biosafety in health centers requires, in addition to correct design and construction, periodic maintenance of the facilities. Objective: Analyze the relationship between the EP and DP and the amount of Colony Forming Units (CFU) of microorganisms in the air and on surfaces. Determine the utility of a Periodic Environmental Biosecurity Assessment Program (PEBAP) to achieve clean air free of microorganisms. Methods: Longitudinal no control intervention study with retrospective data analysis. Samples were recollected as part of a PEBAP of 12 health centers from 2010 to 2017. Environmental parameters (CFU/m3 of fungi and bacteria in the air, CFU/100cm2 of bacteria on surfaces and floors, temperature and relative humidity), and design parameters (differential pressure, air changes per hour, and position of the HEPA filter) were recollected. Microbiological air samples were taken: below the air discharge outlet (point 1), and in the center of the room (point 2), by trained people, external to the centers, with calibrated equipment, in previously cleaned rooms, with equipment operating and no staff present. A negative binomial regression was used for the relationship of EP and DP with the CFU of bacteria on surfaces, a logistic regression was used for the relationship of EP and DP with the presence of fungi in the air, and the Chi-square test was used and for the comparison of continuous variables. Results: In the multivariate models, an increase in temperature was associated with an increase in bacteria on surfaces (IRR=1.224; 95%CI:1.05-1.43) and on floors (IRR=1.259;95% CI:1.06-1.50) and an increase in renewals per hour with a decrease in bacteria on surfaces (IRR=0.961; 95%CI:0.94-0.99) and on floors (IRR=0.975; 95%CI:0.95-1.009). An increase in the presence of fungi in the air was associated with a non-terminal position of the HEPA filters (OR= 6.78; 95% CI: 3.77-12.20) and (OR=4.43;95%CI:2.65-7.40) at point 1 and 2, respectively, with temperature (OR=1.23;95%CI:1.06-1.41) at point 2, and with differential pressure (OR=0.86;95% CI:0.84-0.90) and (OR=0.88; 95%CI:0.86-0.91) at points 1 and 2, respectively. Throughout the PPEBA we found a significant reduction (p < ,05) in the percentage of air fungi in the air. Aspergillus spp. was the most common opportunistic fungus in controlled environment rooms in eastern Spain. Conclusions: Our results show that an increase in temperature and a decrease in renewals per hour increases the amount of CFU of bacteria on surfaces. The HEPA filter in terminal position in the air conditioning system reduces the presence of fungi in the air. PPEBAs are a useful tool to maintain and improve air quality in hospitals. Aspergillus spp. was the most common opportunistic fungus in controlled environment rooms in southeastern Spain.