Environmental health and biosecurity in pig farms and surroundings are increasingly threatened by pathogenic bacteria carried by fine particulate matter with an aerodynamic diameter of 2.5 μm or less (PM2.5) in enclosed piggeries. However, limited attention has been given to these pathogens and their association with the respiratory microbiome of pigs. Using high-throughput sequencing, we investigated the overall and pathogenic bacterial communities attached to PM2.5 in pig houses, as well as those in the upper (URT) and lower respiratory tracts (LRT) of healthy fattening pigs. Concentrations of PM2.5, particulate matter with an aerodynamic diameter of 10 μm or less (PM10), ammonia (NH3), total volatile organic compounds (TVOCs), and hydrogen sulfide (H2S) were significantly higher inside the piggery than in the surrounding environment. The composition of PM2.5-associated bacteria varied with sampling height and showed greater similarity to the microbiota of the URT, particularly the oropharynx, than to that of the LRT. Additionally, 140 core potential bacterial pathogens were identified via Venn analysis in both PM2.5 and respiratory tracts. Co-occurrence network analysis and community assembly patterns revealed that microbial communities in PM2.5 and the respiratory tract exhibit distinct interaction and assembly characteristics. These findings highlight the potential role of PM2.5 as a vector for respiratory pathogens and underscore the importance of air quality management in pig farming to safeguard environmental health.
Tian et al. (Tue,) studied this question.