title: Abundance of antibiotic resistance genes in environmental bacteriophages.
abstract: The ecosystem is continuously exposed to a wide variety of antimicrobials through waste effluents, agricultural run-offs and animal-related and anthropogenic activities, which contribute to the spread of antibiotic resistance genes (ARGs). The contamination of ecosystems with ARGs may create increased opportunities for their transfer to naive microbes and eventually lead to entry into the human food chain. Transduction is a significant mechanism of horizontal gene transfer in natural environments, which has traditionally been underestimated as compared to transformation. We explored the presence of ARGs in environmental bacteriophages in order to recognize their contribution in the spread of ARGs in environmental settings. Bacteriophages were isolated against environmental bacterial isolates, purified and bulk cultured. They were characterized, and detection of ARG and intI genes including blaTEM, blaOXA-2, intI1, intI2, intI3, tetA and tetW was carried out by PCR. This study revealed the presence of various genes [tetA (12.7 %), intI1 (10.9 %), intI2 (10.9 %), intI3 (9.1 %), tetW (9.1 %) and blaOXA-2 (3.6 %)] and blaTEM in a significantly higher proportion (30.9 %). blaSHV, blaOXA-1, tetO, tetB, tetG, tetM and tetS were not detected in any of the phages. Soil phages were the most versatile in terms of ARG carriage. Also, the relative abundance of tetA differed significantly vis-à-vis source. The phages from organized farms showed varied ARGs as compared to the unorganized sector, although blaTEM ARG incidences did not differ significantly. The study reflects on the role of phages in dissemination of ARGs in environmental reservoirs, which may provide an early warning system for future clinically relevant resistance mechanisms.
authors.affiliation: National Centre for Veterinary Type Culture Collection, Bagla Road, Hisar, Haryana 125 001, India.
authors.forename: Taruna
authors.initials: T
authors.lastname: Anand
authors.affiliation: National Centre for Veterinary Type Culture Collection, Bagla Road, Hisar, Haryana 125 001, India.
authors.forename: Bidhan Ch
authors.initials: BC
authors.lastname: Bera
authors.affiliation: National Centre for Veterinary Type Culture Collection, Bagla Road, Hisar, Haryana 125 001, India.
authors.forename: Rajesh K
authors.initials: RK
authors.lastname: Vaid
authors.affiliation: National Centre for Veterinary Type Culture Collection, Bagla Road, Hisar, Haryana 125 001, India.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Barua
authors.affiliation: National Centre for Veterinary Type Culture Collection, Bagla Road, Hisar, Haryana 125 001, India.
authors.forename: Thachamvally
authors.initials: T
authors.lastname: Riyesh
authors.affiliation: ICAR-National Research Centre on Equines, Sirsa Road, Hisar, Haryana 125 001, India.
authors.forename: Nitin
authors.initials: N
authors.lastname: Virmani
authors.affiliation: National Centre for Veterinary Type Culture Collection, Bagla Road, Hisar, Haryana 125 001, India.
authors.forename: Mubarik
authors.initials: M
authors.lastname: Hussain
authors.affiliation: ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243 122, India.
authors.forename: Raj K
authors.initials: RK
authors.lastname: Singh
authors.affiliation: National Centre for Veterinary Type Culture Collection, Bagla Road, Hisar, Haryana 125 001, India.|ICAR-National Research Centre on Equines, Sirsa Road, Hisar, Haryana 125 001, India.
authors.forename: Bhupendra N
authors.initials: BN
authors.lastname: Tripathi
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D001435:Bacteriophages / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D004783:Environmental Microbiology; D022761:Gene Transfer, Horizontal; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D014764:Viral Proteins