Affiliation:
1. Department of Nutrition and Food Science
2. Joint Institute for Food Safety and Applied Nutrition, University of Maryland, College Park, Maryland 20742
3. Center for Veterinary Medicine, Food and Drug Administration, Laurel, Maryland 20708
4. Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, Maryland 20740
Abstract
ABSTRACT
To determine the presence of Shiga toxin-producing
Escherichia coli
(STEC) and other potentially diarrheagenic
E. coli
strains in retail meats, 7,258
E. coli
isolates collected by the U.S. National Antimicrobial Resistance Monitoring System (NARMS) retail meat program from 2002 to 2007 were screened for Shiga toxin genes. In addition, 1,275 of the
E. coli
isolates recovered in 2006 were examined for virulence genes specific for other diarrheagenic
E. coli
strains. Seventeen isolates (16 from ground beef and 1 from a pork chop) were positive for
stx
genes, including 5 positive for both
stx
1
and
stx
2
, 2 positive for
stx
1
, and 10 positive for
stx
2
. The 17 STEC strains belonged to 10 serotypes: O83:H8, O8:H16, O15:H16, O15:H17, O88:H38, ONT:H51, ONT:H2, ONT:H10, ONT:H7, and ONT:H46. None of the STEC isolates contained
eae
, whereas seven carried enterohemorrhagic
E. coli
(EHEC)
hlyA
. All except one STEC isolate exhibited toxic effects on Vero cells. DNA sequence analysis showed that the
stx
2
genes from five STEC isolates encoded mucus-activatable Stx2d. Subtyping of the 17 STEC isolates by pulsed-field gel electrophoresis (PFGE) yielded 14 distinct restriction patterns. Among the 1,275 isolates from 2006, 11 atypical enteropathogenic
E. coli
(EPEC) isolates were identified in addition to 3 STEC isolates. This study demonstrated that retail meats, mainly ground beef, were contaminated with diverse STEC strains. The presence of atypical EPEC strains in retail meat is also of concern due to their potential to cause human infections.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
58 articles.
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