title: Resistance gene transfer during treatments for experimental avian colibacillosis.
abstract: An experiment was conducted in animal facilities to compare the impacts of four avian colibacillosis treatments-oxytetracycline (OTC), trimethoprim-sulfadimethoxine (SXT), amoxicillin (AMX), or enrofloxacin (ENR)-on the susceptibility of Escherichia coli in broiler intestinal tracts. Birds were first orally inoculated with rifampin-resistant E. coli strains bearing plasmid genes conferring resistance to fluoroquinolones (qnr), cephalosporins (bla(CTX-M) or bla(FOX)), trimethoprim-sulfonamides, aminoglycosides, or tetracyclines. Feces samples were collected before, during, and after antimicrobial treatments. The susceptibilities of E. coli strains were studied, and resistance gene transfer was analyzed. An increase in the tetracycline-resistant E. coli population was observed only in OTC-treated birds, whereas multiresistant E. coli was detected in the dominant E. coli populations of SXT-, AMX-, or ENR-treated birds. Most multiresistant E. coli strains were susceptible to rifampin and exhibited various pulsed-field gel electrophoresis profiles, suggesting the transfer of one of the multiresistance plasmids from the inoculated strains to other E. coli strains in the intestinal tract. In conclusion, this study clearly illustrates how, in E. coli, "old" antimicrobials may coselect antimicrobial resistance to recent and critical molecules.
authors: ANSES, Laboratoire de Ploufragan, Unité Mycoplasmologie Bactériologie, Ploufragan, France.
authors: Alexandra
authors: A
authors: Dheilly
authors: Laëtitia
authors: L
authors: Le Devendec
authors: Gwenaëlle
authors: G
authors: Mourand
authors: Axelle
authors: A
authors: Bouder
authors: Eric
authors: E
authors: Jouy
authors: Isabelle
authors: I
authors: Kempf
mesh_terms: D000658:Amoxicillin / Q000008:administration & dosage; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D015373:Bacterial Typing Techniques; D001715:Bird Diseases / Q000188:drug therapy / Q000382:microbiology; D002645:Chickens; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D016521:Electrophoresis, Gel, Pulsed-Field; D000077422:Enrofloxacin; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary; D029968:Escherichia coli Proteins / Q000235:genetics*; D005243:Feces / Q000382:microbiology; D024841:Fluoroquinolones / Q000008:administration & dosage; D022761:Gene Transfer, Horizontal; D008826:Microbial Sensitivity Tests; D010118:Oxytetracycline / Q000008:administration & dosage; D010957:Plasmids / Q000235:genetics; D013412:Sulfadimethoxine / Q000008:administration & dosage; D014295:Trimethoprim / Q000008:administration & dosage
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D024841:Fluoroquinolones; D013412:Sulfadimethoxine; D000077422:Enrofloxacin; D000658:Amoxicillin; D014295:Trimethoprim; D010118:Oxytetracycline