Impact of dust exposure on mixed bacterial cultures and during eukaryotic cell co-culture infections

Abstract

On a daily basis, humans, and their colonizing microbiome, are exposed to both indoor and outdoor dust, containing both deleterious organic and inorganic contaminants, through dermal contact, inhalation, and ingestion. Recent studies evaluating the dust exposure responses of opportunistic pathogens, such as Escherichia coli and Pseudomonas aeruginosa, revealed significant increases in biofilm formation following dust exposure. In this study, the effects of dust exposure on mixed bacterial cultures as well as HT-29 co-cultures were evaluated. As it was observed in pure, single bacterial cultures earlier, neither indoor nor outdoor dust exposure (at concentrations of 100 μg/mL) influenced the growth of mixed bacterial liquid cultures. However, when in paired mixed cultures, dust exposure increased sensitivity to oxidative stress and significantly enhanced biofilm formation (outdoor dust). More specifically, mixed cultures (E. coli-Klebsiella pneumoniae, K. pneumoniae-P. aeruginosa, and E. coli-P. aeruginosa) exhibited increased sensitivity to 20 and 50 mM of HO in comparison to their pure, single bacterial culture counterparts and significantly enhanced biofilm production for each mixed culture. Finally, bacterial proliferation during a eukaryotic gut cell (HT29) co-culture was significantly more robust for both K. pneumoniae and P. aeruginosa when exposed to both house and road dust; however, E. coli only experienced significantly enhanced proliferation, in HT29 co-culture, when exposed to road dust. Taken together, our findings demonstrate that bacteria respond to dust exposure differently when in the presence of multiple bacterial species or when in the presence of human gut epithelial cells, than when grown in isolation.

Airborne Particulates Affect Corneal Homeostasis and Immunity

“… 37 , 38 In addition, limited in vitro studies using human corneal epithelial cells (HCET), have suggested, but did not provide mechanisms, by which PM 2.5 may promote autophagy, 39 damage mitochondrial function, 40 decrease cell viability, 41 and cause oxidative damage. 41 If bacteria are present, exposure of mucosal sites to PM may also enhance bacterial stress resistance mechanisms, 42 , 43 biofilm formation, 42 , 43 and enhance colonization. 42 , 43 In this regard, epidemiologic studies strongly suggest that it is biologically plausible to hypothesize that exposure to PM 2.5 is associated with some of the major blinding and painful eye conditions seen worldwide, including the development of corneal ulcers resulting from delayed wound healing after injury or infection.…”

“… 41 If bacteria are present, exposure of mucosal sites to PM may also enhance bacterial stress resistance mechanisms, 42 , 43 biofilm formation, 42 , 43 and enhance colonization. 42 , 43 In this regard, epidemiologic studies strongly suggest that it is biologically plausible to hypothesize that exposure to PM 2.5 is associated with some of the major blinding and painful eye conditions seen worldwide, including the development of corneal ulcers resulting from delayed wound healing after injury or infection. 5 Those studies further suggest that it is difficult to study clinical disease retrospectively and that experimental models are needed to test mechanistically the relationship between PM 2.5 exposure and ocular disease and infection.…”

From one species to another: A review on the interaction between chemistry and microbiology in relation to cleaning in the built environment

“…114 While plenty of information about commonly used probiotic species is available on their capacity in the laboratory, information justifying the selection of these as probiotic species is less abundant. 114 While plenty of information about commonly used probiotic species is available on their capacity in the laboratory, information justifying the selection of these as probiotic species is less abundant.…”

“…Exposure to outdoor dust enhanced the biofilm formation of a number of bacterial pathogens as well as their ability to proliferate in co-culture with human cells. 114 While plenty of information about commonly used probiotic species is available on their capacity in the laboratory, information justifying the selection of these as probiotic species is less abundant. For example, data stemming from studies involving in vitro experimentation using dust communities or in situ experimentation in complex, occupied built environments is lacking.…”

Potential toxic metals in household dusts extracted in simulated body fluids and their interaction with culturable pathogens responses

“…Furthermore, previous studies have indicated that the indoor dust exposure affects the growth, bio lm formation, oxidative stress, and virulence of microorganisms [6, [21][22][23][24][25][26][27]. Unfortunately, these studies conducted under controlled conditions, and little is known about the physiological impact of dust exposure on the microorganisms.…”