Microbiological analysis of bioaerosols collected from Hospital Emergency Departments and ambulances

The goal of the study was a microbiological, qualitative and quantitative analysis of bioaerosol at the workplace of medical personnel (Health Emergency Departments (HEDs), ambulances), and comparative administration offices with an expected neutral occupational exposure to biological agents measured with individual Button Sampler.

Personal sampling was performed with Button Sampler instrument loaded with gelatine filters in 10 HEDs, in 9 ambulances and in 9 offices to assess the occupational biological agents' exposure in air. Sampling was conducted from March until April 2016. Samples were quantitatively assessed for viable and total number of bacteria and fungi. Routine procedures for microbiological diagnostics were implemented. Data were analysed using Kruskal-Wallis and Mann-Whitney statistical tests with α=0.05. P value less than 0.05 were considered significant.

At the workplaces assessed, the concentrations of viable microorganisms in HEDs were 1.3×10² - 4.2×10³ CFU/m³ for bacteria, 3.4×10⁰ - 8.1×10¹ CFU/m³ for fungi; in ambulances 1.3×10² - 1.4×10³ CFU/m³ (bacteria), 6.7×10⁰ - 6.5×10² CFU/m³ (fungi) and in offices 4.2×10¹ - 5.0×10³ CFU/m³ (bacteria), 0 - 7.9×10² CFU/m³(fungi). In outdoor air, the number of microorganisms reached the level: 1.0×10² - 5.9×10² CFU/m³ for bacteria and 1.5×10² - 8.2×10² CFU/m³ for fungi. The predominant isolated bacteria were Gram-positive cocci. The prevalent fungi species belonged to the genus Aspergillus and Penicillium.

The quantitative assessment of examined indoor air was similar to control outdoor air, and were relatively low. The level of microbiological contamination did not exceed 5×10³ CFU/m³ which is recommended as an admissible level in public spaces in Poland.