The Role of Mobile Genetic Elements in the Spread of Antimicrobial-Resistant Escherichia coli From Chickens to Humans in Small-Scale Production Poultry Operations in Rural Ecuador

Am J Epidemiol. 2018 Mar 1;187(3):558-567. doi: 10.1093/aje/kwx286.

Abstract

Small-scale production poultry operations are increasingly common worldwide. To investigate how these operations influence antimicrobial resistance and mobile genetic elements (MGEs), Escherichia coli isolates were sampled from small-scale production birds (raised in confined spaces with antibiotics in feed), household birds (no movement constraints; fed on scraps), and humans associated with these birds in rural Ecuador (2010-2012). Isolates were screened for genes associated with MGEs as well as phenotypic resistance to 12 antibiotics. Isolates from small-scale production birds had significantly elevated odds of resistance to 7 antibiotics and presence of MGE genes compared with household birds (adjusted odds ratio (OR) range = 2.2-87.9). Isolates from humans associated with small-scale production birds had elevated odds of carrying an integron (adjusted OR = 2.0; 95% confidence interval (CI): 1.06, 3.83) compared with humans associated with household birds, as well as resistance to sulfisoxazole (adjusted OR = 1.9; 95% CI: 1.01, 3.60) and trimethoprim/sulfamethoxazole (adjusted OR = 2.1; 95% CI: 1.13, 3.95). Stratifying by the presence of MGEs revealed antibiotic groups that are explained by biological links to MGEs; in particular, resistance to sulfisoxazole, trimethoprim/sulfamethoxazole, or tetracycline was highest among birds and humans when MGE exposures were present. Small-scale production poultry operations might select for isolates carrying MGEs, contributing to elevated levels of resistance in this setting.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Chickens
  • Drug Resistance, Microbial / genetics*
  • Drug Resistance, Microbial / immunology
  • Ecuador / epidemiology
  • Escherichia coli / genetics*
  • Escherichia coli / immunology
  • Escherichia coli Infections / epidemiology
  • Escherichia coli Infections / microbiology
  • Escherichia coli Infections / transmission*
  • Female
  • Food Industry
  • Humans
  • Interspersed Repetitive Sequences / immunology*
  • Male
  • Occupational Diseases / epidemiology*
  • Occupational Diseases / immunology
  • Occupational Diseases / microbiology
  • Poultry / immunology
  • Poultry / microbiology*
  • Rural Population