The Distribution Characteristic of Microbial Aerosols Inside a Nursery Pig House and the Respiratory Tract of Piglets

Abstract

<jats:title>Abstract</jats:title> <jats:p><jats:bold>Background: </jats:bold>The particulate matter (PM) is a carrier of many substances. Microorganisms are vital constituents contained in PM and the kinds and concentration are closely connected to human health and animal production. This study was aimed to investigate the distribution characteristics of microbial aerosols inside the pig house and as well as in the respiratory tract of pigs. The environment inside a nursery pig house was monitored in winter, including temperature, relative humidity, TSP, PM<jats:sub>10</jats:sub>, PM<jats:sub>2.5</jats:sub>, NH<jats:sub>3</jats:sub>, CO<jats:sub>2</jats:sub>, CO and NO. The concentrations of airborne culturable bacteria, fungi and <jats:italic>Escherichia coli</jats:italic> were detected. Then 16 S rRNA sequencing technology was applied to identify bacteria contained in different sized PM and the bacteria in the respiratory tract of piglets.<jats:bold>Results: </jats:bold>The results showed that the concentration of airborne culturable bacteria inside the pig house was significantly higher than that outside. The concentration of airborne culturable bacteria was reduced with the decrease of the size of PM; the concentration of airborne culturable fungi was mostly distributed in the size of 2.1-3.3 μm and 1.1-2.1 μm PM; most airborne culturable<jats:italic> Escherichia coli</jats:italic> were distributed in the size of &gt;7.0 μm and 2.1-3.3 μm. Besides, these three types of microbial aerosols did not exhibit significant change during different time points. The 16 S rRNA results showed that the bacteria contained in PM had high similarity with that in the respiratory tract of pigs. The bacteria assemblage in the size of 1.1-3.3 μm PM had high similarity with that in the lower respiratory tract (bronchus and lung) of pigs. In addition, four potential pathogenic bacteria genera (<jats:italic>Escherichia-Shigella</jats:italic>, <jats:italic>Streptococcus</jats:italic>, <jats:italic>Acinetobacter</jats:italic>, <jats:italic>Pseudomonas</jats:italic>) were identified in the PM samples and the respiratory tract.<jats:bold>Conclusions: </jats:bold>These results will provide a significant scientific basis in exploring the potential risk of aerosol from animal houses for human and animal health.</jats:p>