title: Antibiotic resistance of gram-negative bacteria in rivers, United States.
abstract: Bacteria with intrinsic resistance to antibiotics are found in nature. Such organisms may acquire additional resistance genes from bacteria introduced into soil or water, and the resident bacteria may be the reservoir or source of widespread resistant organisms found in many environments. We isolated antibiotic-resistant bacteria in freshwater samples from 16 U.S. rivers at 22 sites and measured the prevalence of organisms resistant to beta-lactam and non-beta-lactam antibiotics. Over 40% of the bacteria resistant to more than one antibiotic had at least one plasmid. Ampicillin resistance genes, as well as other resistance traits, were identified in 70% of the plasmids. The most common resistant organisms belonged to the following genera: Acinetobacter, Alcaligenes, Citrobacter, Enterobacter, Pseudomonas, and Serratia.
authors.affiliation: Department of Biology, Washburn University, Topeka, KS 66621, USA. zzash@washburn.edu
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Ash
authors.forename: Brena
authors.initials: B
authors.lastname: Mauck
authors.forename: Melissa
authors.initials: M
authors.lastname: Morgan
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000668:Ampicillin Resistance / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002439:Cefotaxime / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D005618:Fresh Water / Q000382:microbiology*; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D014481:United States
chemical_list: D000900:Anti-Bacterial Agents; D000667:Ampicillin; D002439:Cefotaxime