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

Abstract 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 a wastewater treatment plant (WWTP) (site 10) ( P aac-(6′)-lb-cr gene was significantly higher than the bla CTX-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.