Distribution of Antibiotic Resistance Genes within Viral Metagenomes along the Han River

초록

As high abundance and wide dispersion of bacteriophages (phages) have been recognized, their ecological role as bacterial gene transfer agents has also been emphasized. While phages replicate within host, the host bacteria’s genes can be packaged into newly produced viral capsids. The virus-packaged bacterial genes then have the possibility to be inserted into another bacterial cell upon subsequent infection. Among diverse bacterial genes that are carried by their phages, antibiotic resistance genes (ARGs) are considered especially important for their clinical significance. As viral metagenomes (viromes) of diverse environments have become available, ARGs have been found from diverse viromes, sometimes within viral contigs. However, whether phage-carried ARGs that were discovered from viromes truly have antibiotic resistant phenotype has been a debate. The Han River is one of the largest river body located in South Korea. As the Han River flows through the Seoul metropolitan area, diverse anthropological influences affect aquatic ecosystem. Hence, we collected surface water samples from the Han River to perform virome analysis to screen for ARGs carried by the phages. Commonly known ARGs conferring resistance against quinolones, vancomycin, and beta-lactams were found in viral metagenome reads. Furthermore, beta-lactamase genes with highly conserved active sites were detected within virome contigs. The ARGs found within virome contigs were also found in concurrently performed bacterial metagenome reads, indicating the possibility of phage-carried ARGs to be transferred between phages and their hosts. Keywords: bacteriophage, viral metagenome, antibiotic resistance gene, beta-lactamase