This research aims to evaluate the relationship between the environmental and design parameters of the air conditioning system, and the presence of colony-forming units (CFUs) of bacteria on surfaces. This retrospective study was carried out in controlled environment rooms in 12 hospitals in Spain, as part of a periodic environmental biosecurity assessment programme. Between 2010 and 2017, a total amount of 1027 samples were collected from floors and 861 from hand contact surfaces (HCSs), and the environmental parameters (temperature, relative humidity, fungal and bacterial CFUs present in the air) and design parameters (air changes per hour (ACH), differential pressure and position of the high efficiency particulate air filter) were monitored. The multivariate analysis concluded that, for each increased degree Celsius of temperature, the bacterial CFUs increased by 22.4% (incidence rate ratio (IRR): 1.224, 1.05–1.43) and by 25.9% (IRR: 1.259, 1.06–1.50) on HCSs and floors, respectively, and for each increase in ACH, the CFUs decreased 3.9% (IRR: 0.961, 0.94–0.99) and 2.5% (IRR: 0.975, 0.95–1.00) on HCSs and floors, respectively. Our results show the influence of the environmental and design parameters of air conditioning on the number of CFUs on surfaces and floors.

Aim: Determine the utility of the Periodic Environmental Biosecurity Assessment Program (PEBAP) in achieving clean air as measured by the number of colony-forming units (CFU) of fungi and bacteria in the air. Background: There is no international consensus on the sampling frequency, the recommended limits for microorganisms in the air nor on the usefulness of routine microbiological air monitoring of hospitals. Methods: During the PEBAP, data were recollected between 2010 and 2017 in eight hospitals in southeast Spain. Air samples were collected in very high risk rooms (VHRRs) and high risk rooms (HRRs), unoccupied, using active sampling methods. Temperature, relative humidity, air changes per hour (ACH), and differential pressure were measured. When limits of CFU of opportunistic fungi and bacteria established in the PEBAP were exceeded, corrective measures were adopted. Results: We found a reduction ( p < .01) of percentage of air samples with fungi growth throughout the years of PEBAP in all rooms. Aspergillus was the most frequent opportunistic fungus. We found a high compliance of the standards of CFU of bacteria in HRR, and the percentage of compliance in VHRR was lower than in HRR in all years. Differences in environmental and design parameters were statistically significant ( p < .05) between rooms, except for ACH. Conclusions: PEBAP resulted in a useful tool to maintain and improve air quality in hospitals. The control of environmental biosecurity requires a multidisciplinary approach from preventive medicine, engineering, and cleaning services. Aspergillus is the most frequent opportunistic fungus in southeast Spain.

Aim: Establish the influence of the terminal or nonterminal position of High Efficiency Particulate Air (HEPA) filters in the Heating, Ventilation, and Air Conditioning (HVAC) system on the presence of airborne fungi in controlled environment rooms. Background: Fungal infections are an important cause of morbidity and mortality in hospitalized patients. Methods: This study was realized from 2010 to 2017, in rooms with terminal and nonterminal HEPA filters, in eight Spanish hospitals. In rooms with terminal HEPA filters, 2,053 and 2,049 samples were recollected, and in rooms with nonterminal HEPA filters, 430 and 428 samples were recollected in the air discharge outlet (Point 1) and in the center of the room (Point 2), respectively. Temperature, relative humidity, air changes per hour, and differential pressure were recollected. Results: Multivariable analysis showed higher odds ratio ( OR) of airborne fungi presence when HEPA filters were in nonterminal position ( OR: 6.78; 95% CI [3.77, 12.20]) in Point 1 and ( OR: 4.43; 95% CI [2.65, 7.40]) in Point 2. Other parameters influenced airborne fungi presence, such as temperature ( OR: 1.23; 95% CI [1.06, 1.41]) in Point 2 differential pressure ( OR: 0.86; 95% CI [0.84, 0.90]) and ( OR: 0.88; 95% CI [0.86, 0.91]) in Points 1 and 2, respectively. Conclusions: HEPA filter in terminal position of the HVAC system reduces the presence of airborne fungi. To decrease the presence of airborne fungi, adequate maintenance of the environmental and design parameters is necessary in addition to the terminal position of the HEPA filter.