Pathogenic bacteria and antibiotic resistance genes in hospital indoor bioaerosols: pollution characteristics, interrelation analysis, and inhalation risk assessment

Hospitals are high risk areas for the spread of diseases, with indoor bioaerosols containing a variety of pathogens. Inhalation of these pathogens may cause severe nosocomial infections in patients and medical staff. A comprehensive investigation was conducted during the influenza A outbreak to explore the distribution and pathogenic risk of airborne pathogens and antibiotic resistance genes (ARGs) across different hospital departments. It was revealed that airborne bacterial concentrations ranged from 118 to 259 CFU/m3, and the main aerosol particle size was 4.7-5.8 mu m (27.7 %). The proportion of bioaerosols smaller than 2.5 mu m was highest in the respiratory waiting area (59.3 %). The dominant pathogens detected in hospital air were Bacillus, Staphylococcus, Pseudomonas and Micrococcus. The absolute abundance of ARGs/mobile genetic elements (MGEs) ranged from 0.55 to 479.44 copies/m3, peaking in the respiratory ward air. TetL-02, lnuA-01, intI1, ermB, and qacEdelta1-02 were the top five ARGs/MGEs in hospital air. Moreover, doctors inhaled higher doses of ARGs/ MGEs in inpatient wards than outpatient waiting areas. Network analysis identified Pseudomonas, Micrococcus, Microbacterium, and Enterobacter as potential ARGs reservoirs. The Bugbase result showed the presence of potentially pathogenic pathogens in the bioaerosols at all sampling sites. The quantitative microbiological risk assessment results further showed that airborne Staphylococcus could pose an infection risk to medical staff. It was determined that the use of masks was effective in reducing this risk to an acceptable level. This study will provide a scientific basis for comprehensively understanding the characteristics and potential risks of hospital bioaerosols during the outbreak of respiratory infectious diseases.