title: Antimicrobial susceptibilities of Escherichia coli strains from a turkey operation.
abstract: OBJECTIVE
  To measure minimum inhibitory concentrations (MIC) of 17 antimicrobials for Escherichia coli isolates from a turkey operation and assess whether small samples provide precise estimates of geometric mean MIC.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  105 clinical isolates from birds and 1,104 fecal isolates from 20 flocks (poults and finisher hens).
  
  
  METHODS
  A Mueller-Hinton broth dilution panel was used to measure MIC, and MIC of fecal and clinical isolates were compared. We drew random samples of 5,10, 15, 20, 25, 30, 35, 40, and 45 isolates from each finisher flock and between 100 and 105 isolates from 5, 7, 10, and 20 flocks. Antimicrobial usage was determined for enrolled flocks.
  
  
  RESULTS
  Six of 12 poult and 18 of 20 finisher flocks had been treated with antimicrobials, often for respiratory illnesses consistent with colibacillosis. All birds received gentamicin at the hatchery. More fecal than clinical isolates were resistant to ampicillin; however, more clinical isolates were resistant to ciprofloxacin, gentamicin, and sulfamethoxazole. Precise estimates of geometric mean MIC for flocks were obtained when > or = 15 fecal isolates were obtained per flock and, for the operation, when 105 isolates were obtained from > or = 7 flocks.
  
  
  CONCLUSIONS
  Antimicrobial usage was common and may have contributed to the resistance patterns of isolates. With a modest allocation of laboratory resources, producers can monitor antimicrobial susceptibilities of clinical and fecal E coli to manage risks of antimicrobial usage and resistance.
authors.affiliation: Food and Drug Administration, Center for Veterinary Medicine, Rockville, MD 20895, USA.
authors.forename: Sean F
authors.initials: SF
authors.lastname: Altekruse
authors.forename: François
authors.initials: F
authors.lastname: Elvinger
authors.forename: Kyung-Yul
authors.initials: KY
authors.lastname: Lee
authors.forename: Linda K
authors.initials: LK
authors.lastname: Tollefson
authors.forename: E William
authors.initials: EW
authors.lastname: Pierson
authors.forename: Joseph
authors.initials: J
authors.lastname: Eifert
authors.forename: Nammalwar
authors.initials: N
authors.lastname: Sriranganathan
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D015169:Colony Count, Microbial / Q000662:veterinary; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D005243:Feces / Q000382:microbiology; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D011201:Poultry Diseases / Q000188:drug therapy* / Q000382:microbiology; D011446:Prospective Studies; D014422:Turkeys
chemical_list: D000900:Anti-Bacterial Agents