Air pollution alters Staphylococcus aureus and Streptococcus pneumoniae biofilms, antibiotic tolerance and colonisation

Abstract

SummaryAir pollution is the world's largest single environmental health risk (WHO). Particulate matter such as black carbon is one of the main components of air pollution. The effects of particulate matter on human health are well established however the effects on bacteria, organisms central to ecosystems in humans and in the natural environment, are poorly understood. We report here for the first time that black carbon drastically changes the development of bacterial biofilms, key aspects of bacterial colonisation and survival. Our data show that exposure to black carbon induces structural, compositional and functional changes in the biofilms of both S. pneumoniae and S. aureus. Importantly, the tolerance of the biofilms to multiple antibiotics and proteolytic degradation is significantly affected. Additionally, our results show that black carbon impacts bacterial colonisation in vivo. In a mouse nasopharyngeal colonisation model, black carbon caused S. pneumoniae to spread from the nasopharynx to the lungs, which is essential for subsequent infection. Therefore our study highlights that air pollution has a significant effect on bacteria that has been largely overlooked. Consequently these findings have important implications concerning the impact of air pollution on human health and bacterial ecosystems worldwide.

Microbiological Diversity Demonstrates the Potential which Collaboratively Metabolize Nitrogen Oxides ( NOx) under Smog Environmental Stress

“…The smog will be reduced and eliminated if the emission of NOx is controlled effectively [1][2][3][4][5][6][7][8][9]. Currently, energy conservation & emission reduction technology is carried out to tackle its notorious smog problem.…”

“…SO2）and nitrogen oxides（i.e. NOx）produced by coal and fuel motor vehicle [1][2][3][4][5][6][7][8][9][10][11]. In addition, nitrogen oxides can catalyse photochemical reaction to increase pollution [1][2][3][4][5][6][7][8][9][10][11].…”

Particulate air pollution impacts directly on bacterial pathogen behaviour and infection

“…Although mice exposed to S. pneumonia e and BC did not display any overt signs of inflammation and disease, this could be consequence of either a lack of host susceptibility or because BC particles also influence the host immune response to pneumococci. While further work is required to better understand from both bacterial and host perspectives why treatment with BC drives dissemination from the nasopharynx to the lungs, the findings presented (Hussey et al ., ) do offer an explanation, at least in part, of why exposure to particulate matter is associated with lower respiratory tract infections. It is also possible that exposure to air pollution modifies nasopharyngeal microbiome population diversity and clearance in ways that increase host susceptibility to disease.…”

“…Hence Hussey et al . () provide some important groundwork in highlighting the previously overlooked direct impact of BC on microbes, infection and antibiotic susceptibility and set the scene for more mechanistic studies on the bacterial sensing mechanisms involved in controlling microbial responses to BC and promoting bacterial migration from the nasopharynx to the lungs. This work has far reaching implications with respect to air pollution and microbial behaviour in many different ecosystems and should act as a catalyst to stimulate further efforts to better understand how BC affects, for example, microbial diversity, organic matter transport and nutrient assimilation in different ecosystems (Cattaneo et al ., ).…”

“…Perhaps of even greater concern is the authors' observation that in a murine pneumococcal colonization model, BC exposure promoted the spread of S. pneumoniae from the nasopharynx to the lungs. Such dissemination is key to the development of pneumococcal pneumonia (Hussey et al ., ). Although mice exposed to S. pneumonia e and BC did not display any overt signs of inflammation and disease, this could be consequence of either a lack of host susceptibility or because BC particles also influence the host immune response to pneumococci.…”