[Distribution Characteristics of Antibiotic Resistance Genes in PM2.5 of a Concentrated Broiler Feeding Operation].

ABSTRACT

Concentrated poultry feeding operations are an important source of antibiotic resistance genes (ARGs). Little attention has been given to PM2.5 as a mechanism for exposing ARGs to humans. In this study, PM2.5 and fecal samples from inside the broiler feeding operation and PM2.5 samples from outside the broiler feeding operation were collected. All samples were subjected to the determination of class Ⅰ integrin (intI1), total bacterial gene (16S rDNA), and 19 ARGs of six types by quantitative real-time PCR (qPCR). The results indicated that, excluding blaGES-1 and blaSHV-1, the remaining 17 ARGs were detected in all six samples. Sulfonamide resistance genes, tetracycline resistance genes, macrolide resistance genes, and aminoglycoside resistance genes were abundant in the feces, reaching 1.04×109-3.27×1010 copies·g-1, while feces was an important source of antibiotic resistance genes in PM2.5 of the broiler feeding operation. There were high abundances of sulfonamide resistance genes and macrolide resistance genes in PM2.5 from inside the broiler feeding operation, reaching (8.9±1.9)×107 copies·m-3 and (5.6±3.1)×107 copies·m-3, respectively. The abundance of ARGs in the PM2.5 samples from inside the broiler feeding operation was significantly higher compared to the outside PM2.5 samples. There was a significant positive correlation between PM2.5 mass concentration and 16S rDNA, intI1, and ARGs abundance, indicating that PM2.5 was the reservoir and disseminator of airborne bacteria, ARGs, and intI1 in the broiler feeding operation. The abundance of intI1 was higher than ARGs among all samples, and the co-occurring relationship between intI1 and ARGs demonstrates the threat of multi-drug resistance, which is harmful to the surrounding air environment and the health of the breeder and poultry.