Airborne Survival of Escherichia coli under Different Culture Conditions in Synthetic Wastewater.

Wing Lam Chan,Wing Tung Chung,Tsz Wai Ng

doi:10.3390/ijerph16234745

Wing Lam Chan, Wing Tung Chung + Show 1 more

Open Access

https://doi.org/10.3390/ijerph16234745

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Abstract

Bioaerosol generated in wastewater treatment plants has potential to harm human health. Survival of bacteria in bioaerosol during suspension is one of the major factors that affect its biological risk. It is hypothesized that bacteria grown in different wastewater have different physiology and lead to variation in airborne survival. This study investigated the relationship between the cultured conditions and the bioaerosol survival. Synthetic wastewater was used as the culture medium to simulate the water quality of wastewater. Escherichia coli BW25113 were cultured in different conditions, including growth salinity, growth temperature, growth pH, and presence of pesticide. The fatty acid composition and the reduction in airborne survival of the E. coli cultured under these conditions were determined and compared. Results showed that increasing growth salinity and temperature led to a lower reduction in airborne survival of E. coli. E. coli cultured at pH 6 had a higher reduction in airborne survival than those cultured at pH 7 and 8. Moreover, a correlation was observed between the membrane fluidity (fluidity index) and the reduction airborne survival for both aerosolization and airborne suspension. A link between culture conditions, bacterial membrane fluidity, and airborne survival was established. Culture conditions (wastewater quality) that lead to a low membrane fluidity of bacteria increase the airborne survival of bioaerosol, and vice versa. This provides a new aspect to evaluate bioaerosol survival and improve assessment on biological risk of bioaerosols.

Highlights

Wastewater treatment plants (WWTPs) are a major anthropogenic source of bioaerosol.Different processes in WWTPs, such as bubble bursting, scum, and foam formation lead to bioaerosol generation [1,2]
The E. coli showed a higher reduction in survival when it grew at pH 6 (Figure 3)
Bacterial membrane fluidity is a major factor in regard to airborne survival, the results suggested that other physiological changes of E. coli may have affected the airborne survival

Summary

Introduction

Wastewater treatment plants (WWTPs) are a major anthropogenic source of bioaerosol.Different processes in WWTPs, such as bubble bursting, scum, and foam formation lead to bioaerosol generation [1,2]. The generated bioaerosol can be dispersed by the downwind movement [3,4], which causes potential hazards to human health, especially infectious disease, respiratory diseases, and cancer [5,6,7,8,9,10]. Oncogenic viruses and other biological agents such as mold can increase the risk for certain cancers [5,8,9]. Human opportunistic pathogens were always found in the bioaerosol generated from WWTPs [4,12]. Various studies have been conducted to evaluate the biological risk of the bioaerosol generated from WWTPs [3,4,12]

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