title: Widespread distribution of tetracycline resistance genes in a confined animal feeding facility.
abstract: We sought to determine the distribution of resistance and the tetracycline resistance genes among bacteria isolated from a swine confined animal feeding facility where tetracycline-containing feed had been in use for over 20 years. Samples collected from feed, hogs, hog houses, waste lagoon, soil, surface water and well water were screened for the presence of (a) resistant Escherichia coli and enterococci and (b) tetracycline-resistant strains of all species. Genomic DNA was extracted from the latter strain collection and fragments from 16S rDNA and ten tetracycline resistance genes (tetA, tetB, tetC, tetE, tetH, tetL, tetM, tetS, tetT and rumB) were polymerase chain reaction-amplified and a partial nucleotide sequence was obtained. In this environment, 77% of E. coli and 68% of enterococci isolated were tetracycline resistant. Tetracycline resistance was found in 26 different bacterial genera and in 60 species. Single resistance gene alleles (as defined by nucleotide sequence) were present in multiple species. There was evidence of gene recombination and multiple different tetracycline resistance genes were present in single bacterial isolates. These data provide further evidence for the widespread distribution of resistance genes in microbial populations in settings in which there is ongoing subtherapeutic antimicrobial use.
authors.affiliation: Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, 10 S. Pine Street, Baltimore, MD 21201, USA.
authors.forename: O Colin
authors.initials: OC
authors.lastname: Stine
authors.forename: Judith A
authors.initials: JA
authors.lastname: Johnson
authors.forename: Ananda
authors.initials: A
authors.lastname: Keefer-Norris
authors.forename: Kellie L
authors.initials: KL
authors.lastname: Perry
authors.forename: Justine
authors.initials: J
authors.lastname: Tigno
authors.forename: Sadaf
authors.initials: S
authors.lastname: Qaiyumi
authors.forename: Maryruth S
authors.initials: MS
authors.lastname: Stine
authors.forename: J Glenn
authors.initials: JG
authors.lastname: Morris
mesh_terms: D000483:Alleles; D000821:Animal Feed / Q000382:microbiology; D000822:Animal Husbandry; D000818:Animals; D001419:Bacteria / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D016983:Enterococcus / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D004783:Environmental Microbiology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005516:Food Microbiology; D005798:Genes, Bacterial; D012689:Sequence Homology, Nucleic Acid; D034421:Sus scrofa / Q000382:microbiology*; D013753:Tetracycline Resistance / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial