Abstract

Bioaerosol known as biological aerosols gain greater attention in the past decade, a number of disciplines are involved. Besides the concerns with health care sectors with pathogenic bioaerosols, other natural science disciplines such as climatology, physical chemistry, agronomy, and more are involved. From the perspective of OneHealth, a multi-disciplinary approach can increase scientific understanding of bioaerosols to enhance health quality. One example, tuberculosis (TB) is a known airborne pathogen which directly affects the mortality in a global population. In Japan, the number of patients with TB has been decreasing; however, the patients diagnosed with non tuberculous mycobacteriosis (NTM) tend to be increasing in Japan. The previous study indicated the highly polluted industrial region, the number of patients infected with Mycobacterium kansasii tends to be higher in a dusty environment (Mimura, 2002; Yoshida et al., 2011); however, the detailed mechanism is not fully understood. Furthermore, different dust types play an essential role for the survival of bacterial bioaerosols. More specifically, we have suspected that higher organic contents in dust as crucial factor (Noda et al., 2019). In this study, we hypothesized that atmospheric pollutants as an influencing factor for the bioaerosols to evade degradation process and survive in the atmosphere. The viability of Mycobacterium smegmatis (M. smeg) was examined as a model airborne bacteria and freshly generated soot particles as model air pollutant. Aerosolized M. Smeg was introduced into a chamber, then the generated soot with a burning candle was sampled on the filter first then exposed to UV-C ray as stress for a specified period. Afterward, the survival rates were calculated with a culture-based method to determine the colony-forming unit per volume (CFU/mL). The result indicated that the presence of soot contributed to increasing the survival rate of M. smeg significantly (p<0.05). Further results of different bacteria strain, Mycobacterium intracellurale also indicated that presence of soot may have protective function against UV stress. In this investigation, the presence of soot has an important function to prolong the survival of mycobacteria in the atmosphere. However, this investigation focused on the co-existing condition of soot and bacteria on the filter surface for close contact to each other; therefore, we have to further investigate the bioaerosol and soot interaction in the real atmospheric conditions.