Transmission of the genetic determinants of antibiotic resistance from wastewater to the upper respiratory tract of wastewater treatment plant workers and to the aquatic environment

In recent years, high-throughput sequencing technology has shown significant advantages in analyzing environmental microbial communities, providing deeper insight into the antibiotic resistance profile of bacterial populations. The overriding aim of this study was to show that during the mechanical and biological wastewater treatment with the use of activated sludge, bioaerosol is emitted containing a wide range of antibiotic resistance genes and mobile genetic elements that may pose a threat to the employees of the wastewater treatment plant. The obtained results will fill the gap in the scientific literature and emphasize the need for further research on the health risks of workers in mechanical and biological wastewater treatment plants. Moreover, the aim of the study was to characterize the transmission of antibiotic resistance determinants to the river water collecting the wastewater flowing out of the mechanical and biological wastewater treatment plant. By using Illumina Trueseq deep metagenomic sequencing, a taxonomic analysis was performed and the resistome and gene mobility profile were characterized in wastewater samples from three successive treatment stages, river water samples above and below the wastewater discharge and in samples of swabs from the upper respiratory tract of treatment plant workers. In the study, samples were collected in three different seasons of the year, which is dictated by the potential differences in human consumption of antibiotics during the year. These analyzes are in line with the "One health" perspective proposed by the World Health Organization regarding the widespread problem of antibiotic resistance among microorganisms.