title: Diverse tetracycline resistance genotypes of Megasphaera elsdenii strains selectively cultured from swine feces.
abstract: A total of 30 Megasphaera elsdenii strains, selectively isolated from the feces of organically raised swine by using Me109 M medium, and one bovine strain were analyzed for tetracycline resistance genotypic and phenotypic traits. Tetracycline-resistant strains carried tet(O), tet(W), or a tet gene mosaic of tet(O) and tet(W). M. elsdenii strains carrying tet(OWO) genes exhibited the highest tetracycline MICs (128 to >256 microg/ml), suggesting that tet(O)-tet(W) mosaic genes provide the selective advantage of greater tetracycline resistance for this species. Seven tet genotypes are now known for M. elsdenii, an archetype commensal anaerobe and model for tet gene evolution in the mammalian intestinal tract.
authors.affiliation: Pre-Harvest Food Safety and Enteric Diseases Research Unit, National Animal Disease Center, Agricultural Research Service, U.S. Department of Agriculture, Ames, Iowa 50010-0070, USA. tstanton@nadc.ars.usda.gov
authors.forename: Thaddeus B
authors.initials: TB
authors.lastname: Stanton
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: McDowall
authors.forename: Mark A
authors.initials: MA
authors.lastname: Rasmussen
mesh_terms: D000818:Animals; D001421:Bacteria, Anaerobic / Q000145:classification* / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics; D003470:Culture Media; D005243:Feces / Q000382:microbiology*; D014644:Genetic Variation; D005838:Genotype; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D013552:Swine / Q000382:microbiology*; D013752:Tetracycline / Q000494:pharmacology; D013753:Tetracycline Resistance / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D003470:Culture Media; C083139:Tet O resistance protein, Bacteria; D013752:Tetracycline