Prevalence of antibiotic resistance genes in bacteriophage DNA fraction from Funan River water in Sichuan, China

To better understand the role that bacteriophages play in antibiotic resistance genes (ARGs) dissemination in the aquatic environment, 36 water samples were collected from the Funan River in Sichuan, China. The occurrence of 15 clinically relevant ARGs and one class 1 integron gene int1 in phage-particle DNA were evaluated by PCR. The abundance of ARGs (bla(CTX-M), sul1, and aac-(6')-1b-cr) was determined by quantitative PCR (qPCR). High prevalence of the int1 gene (66.7%) was found in the phage-particle DNA of tested samples, followed by sul1 (41.7%), sul2 (33.3%), bla(CTX-M) (33.3%), aac-(6')-lb-cr (25%), aph(3')-IIIa (16.7%), and ermF (8.3%). The qPCR data showed higher gene copy (GC) numbers in samples collected near a hospital (site 7) and awastewater treatment plant (WWTP) (site 10) (P <.05). Particularly the absolute abundance of aac-(6')-lb-cr gene was significantly higher than the blaCTX-M and sul1 genes with the gene copy (GC) numbers of 5.73 log(10) copy/mL for site 7 and 4.99 log(10) copy/mL for site 10. To our best knowledge, this is the first study to report the presence of sul2, aac-(6')-lb-cr, ermF and aph(3')-IIIa genes in bacteriophage DNA derived from aquatic environments. Our findings highlight the potential of ARGs to be transmitted via bacteriophages in the aquatic environment. (C) 2018 Elsevier B.V. All rights reserved.