Assessing bacterial bioaerosol and environmental variables of critical hospitalization units of a tertiary hospital

Bioaerosol components can endanger the indoor air quality (IAQ) in hospital buildings. The bacteria present in bioaerosols may cause hospital-associated infections and increase the number of occupational diseases, harming healthcare workers and patients with vulnerable immune systems. This study aimed to assess the bacteriological contamination of bioaerosols and the IQA parameters in a tertiary hospital. The study was performed in four specialized critical hospitalization units (Infectious Disease, Clinical Oncology, Burn and Plastic Surgery, and Kidney Transplant) located at a tertiary university hospital before and during the SARS-CoV-2 pandemic. Air samples were collected by impaction; a single-stage sampler was used to quantify, to isolate, and to identify airborne bacteria. The environmental variables particulate matter concentration, carbon dioxide concentration, temperature, and relative humidity were analyzed in each sample, on appropriate equipment. The concentration of airborne bacteria varied from 51.22 ± 8.89 to 264.11 ± 161.36 CFU/m³. Of the thirteen bacterial genera identified in the samples, eleven were potentially pathogenic or opportunistic. The environmental variables temperature and relative humidity were higher than indicated. We concluded that IAQ in this hospital must be improved, and that the new sanitary parameters established during the SARS-CoV-2 pandemic influenced positively the concentration of colony-forming units and the total number of bacterial species/strains identified in the two phases of this research. We recommend analyzing other factors that affect bioaerosol composition, so that a complete view of the bioaerosol components can be achieved. A more comprehensive analysis would also allow IAQ control to be adopted in each specialized critical hospitalization unit studied here as well as in other sectors of this hospital and even in other hospitals worldwide.