Molecular Analysis of Escherichia coli from retail meats (2002-2004) from the United States National Antimicrobial Resistance Monitoring System.
BACKGROUND
The origins and virulence potential of meat product-associated Escherichia coli are undefined.


METHODS
Two hundred eighty-seven E. coli isolates (145 resistant and 142 susceptible to trimethoprim-sulfamethoxazole, nalidixic acid, and/or ceftiofur), recovered by the United States National Antimicrobial Monitoring System from retail beef, pork, chicken, and turkey products (from Oregon, Tennessee, Georgia, and Maryland, 2002-2004) underwent polymerase chain reaction testing for phylogenetic groupings and 59 virulence-associated genes.


RESULTS
However analyzed, resistant and susceptible isolates differed minimally according to the assessed characteristics. In contrast, the 4 meat types differed greatly for multiple individual traits and aggregate virulence scores. Poultry isolates exhibited virulence genes associated with avian pathogenic E. coli; beef isolates exhibited traits associated with E. coli from diseased cattle. Overall, 20% of isolates qualified as extraintestinal pathogenic E. coli, with poultry isolates exhibiting significantly higher virulence scores than beef and pork isolates (P < .001).


CONCLUSIONS
Within this systematically collected, geographically distributed sample of recent retail meat isolates, the carriage of extraintestinal pathogenic E. coli virulence genes in antimicrobial-resistant and antimicrobial-susceptible E. coli appeared similar, whereas isolates from different types of meat differed, consistent with on-farm acquisition of resistance within host species-specific E. coli populations. A substantial minority of meat-source E. coli (whether susceptible or resistant) may represent potential human pathogens.
Johnson
James R
JR
Department of Medicine, University of Minnesota, Veterans Affairs Medical Center, Minneapolis, Minnesota 55417, USA.
McCabe
James S
JS
White
David G
DG
Johnston
Brian
B
Kuskowski
Michael A
MA
McDermott
Patrick
P
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D002417:Cattle; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D029968:Escherichia coli Proteins / Q000235:genetics; D005838:Genotype; D006801:Humans; D008460:Meat / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods; D011200:Poultry; D013552:Swine; D014481:United States; D037521:Virulence Factors / Q000235:genetics
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D037521:Virulence Factors