title: Pyrosequencing of antibiotic-contaminated river sediments reveals high levels of resistance and gene transfer elements.
abstract: The high and sometimes inappropriate use of antibiotics has accelerated the development of antibiotic resistance, creating a major challenge for the sustainable treatment of infections world-wide. Bacterial communities often respond to antibiotic selection pressure by acquiring resistance genes, i.e. mobile genetic elements that can be shared horizontally between species. Environmental microbial communities maintain diverse collections of resistance genes, which can be mobilized into pathogenic bacteria. Recently, exceptional environmental releases of antibiotics have been documented, but the effects on the promotion of resistance genes and the potential for horizontal gene transfer have yet received limited attention. In this study, we have used culture-independent shotgun metagenomics to investigate microbial communities in river sediments exposed to waste water from the production of antibiotics in India. Our analysis identified very high levels of several classes of resistance genes as well as elements for horizontal gene transfer, including integrons, transposons and plasmids. In addition, two abundant previously uncharacterized resistance plasmids were identified. The results suggest that antibiotic contamination plays a role in the promotion of resistance genes and their mobilization from environmental microbes to other species and eventually to human pathogens. The entire life-cycle of antibiotic substances, both before, under and after usage, should therefore be considered to fully evaluate their role in the promotion of resistance.
authors.affiliation: Department of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Kristiansson
authors.forename: Jerker
authors.initials: J
authors.lastname: Fick
authors.forename: Anders
authors.initials: A
authors.lastname: Janzon
authors.forename: Roman
authors.initials: R
authors.lastname: Grabic
authors.forename: Carolin
authors.initials: C
authors.lastname: Rutgersson
authors.forename: Birgitta
authors.initials: B
authors.lastname: Weijdegård
authors.forename: Hanna
authors.initials: H
authors.lastname: Söderström
authors.forename: D G Joakim
authors.initials: DG
authors.lastname: Larsson
mesh_terms: D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D001419:Bacteria / Q000187:drug effects / Q000235:genetics; D058448:Biota; D004251:DNA Transposable Elements / Q000502:physiology; D024881:Drug Resistance, Bacterial / Q000187:drug effects / Q000235:genetics; D022761:Gene Transfer, Horizontal / Q000187:drug effects* / Q000502:physiology; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D006801:Humans; D045483:Rivers / Q000737:chemistry; D017422:Sequence Analysis, DNA / Q000379:methods*; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000009:adverse effects*
chemical_list: D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D014874:Water Pollutants, Chemical