Evaluation of Bioaerosol Samplers for Airborne Escherichia Coli Carried by Poultry Litter Particles

Highlights The study demonstrated a methodology to evaluate bioaerosol samplers on collecting Escherichia coli (E. coli) carried by airborne dust. A dry-base aerosolization system was developed for the study. The sampling efficiency of Andersen six-stage impactor and AGI-30 outperformed that of ACD-200 Bobcat. Airborne E. coli might be preferentially aggregated on large particles (> 7.0 µm). Abstract. Pathogenic Escherichia coli (E. coli) are frequently recovered in poultry litter and may be transmitted through the air after bird activities create airborne dust. To assess risks of airborne transmission of E. coli carried by dust, efficient bioaerosol samplers under dry aerosolization conditions are required. The objective of this study was to compare the performance of three commonly used bioaerosol samplers, which included an Andersen six-stage impactor, an all-glass impinger (AGI-30), and an ACD-200 Bobcat (Bobcat), for collecting the airborne E. coli carried by dust particles under dry aerosolization condition in a bio-safety chamber. A dry aerosolization system was designed to generate dry bioaerosols for the study. Under the same airborne E. coli concentration with stable environmental conditions including temperature and relative humidity (RH), the E. coli concentrations determined by the three samplers were 5.05±2.08 log10 colony-forming units (CFU) m-3, 5.69±1.92 log10 CFU m-3, and 2.69±0.81 log10 CFU m-3 for Andersen six-stage impactor, AGI-30, and Bobcat, respectively. The results showed that there is no significant difference between Andersen six-stage impactor and AGI-30, while there was a sizeable decrease in the bacteria concentration determined by the Bobcat sampler. The results also showed that airborne E. coli were preferentially aggregated on large particles (> 7.0 µm). This study demonstrated a methodology to evaluate bioaerosol sampler efficiency using dry-base carriers of biological agents which are predominant in poultry houses. The optimal sampler can be used to determine the airborne E. coli loading in commercial poultry houses. Keywords: Airborne transmission, Bioaerosol samplers, Dry aerosolization, E. coli, Poultry.