title: Antimicrobial-resistant and extraintestinal pathogenic Escherichia coli in retail foods.
abstract: BACKGROUND
  Extraintestinal Escherichia coli infections are associated with specialized extraintestinal pathogenic E. coli (ExPEC) strains and, increasingly, with antimicrobial resistance. The food supply may disseminate ExPEC and antimicrobial-resistant E. coli.
  
  
  METHODS
  In a prospective survey of 1648 diverse food items from 10 retail markets in the Minneapolis-St. Paul area during 2001-2003, selective cultures and disk-diffusion assays for the isolation and characterization of antimicrobial-resistant E. coli and polymerase chain reaction-based assays and O serotyping to define ExPEC-associated traits were performed.
  
  
  RESULTS
  E. coli contamination exhibited a prevalence gradient from miscellaneous foods (9%), through beef or pork (69%), to poultry (92%; P<.001). Among E. coli-positive samples, similar prevalence gradients were detected for antimicrobial resistance (27%, 85%, and 94% of samples, respectively; P<.001) and ExPEC contamination (4%, 19%, and 46%, respectively; P<.001). By multivariate analysis, beef or pork and poultry from natural-food stores exhibited reduced risks of E. coli contamination and antimicrobial resistance. Indirect evidence suggested on-farm selection of resistance. Four food-source ExPEC isolates (from pea pods, turkey parts, ground pork, and vegetable dip) closely resembled selected human clinical isolates by O antigen and genomic profile.
  
  
  CONCLUSIONS
  Retail foods may be an important vehicle for community-wide dissemination of antimicrobial-resistant E. coli and ExPEC, which may represent a newly recognized group of medically significant foodborne pathogens.
authors.affiliation: Mucosal and Vaccine Research Center, Veterans Affairs Medical Center, and Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55417, USA. johns007@umn.edu
authors.forename: James R
authors.initials: JR
authors.lastname: Johnson
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kuskowski
authors.forename: Kirk
authors.initials: K
authors.lastname: Smith
authors.forename: Timothy T
authors.initials: TT
authors.lastname: O'Bryan
authors.forename: Sita
authors.initials: S
authors.lastname: Tatini
mesh_terms: D000818:Animals; D002417:Cattle; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000145:classification* / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology* / Q000635:transmission*; D005516:Food Microbiology; D005517:Foodborne Diseases; D006801:Humans; D008460:Meat / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D019081:O Antigens / Q000235:genetics; D016133:Polymerase Chain Reaction; D011202:Poultry Products / Q000382:microbiology; D012641:Selection, Genetic; D012703:Serotyping; D013552:Swine
chemical_list: D019081:O Antigens