title: Presence and characterization of shiga toxin-producing Escherichia coli and other potentially diarrheagenic E. coli strains in retail meats.
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.
authors.affiliation: Department of Nutrition and Food Science, 0112 Skinner Building, University of Maryland, College Park, MD 20742-7521, USA.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Xia
authors.forename: Jianghong
authors.initials: J
authors.lastname: Meng
authors.forename: Patrick F
authors.initials: PF
authors.lastname: McDermott
authors.forename: Sherry
authors.initials: S
authors.lastname: Ayers
authors.forename: Karen
authors.initials: K
authors.lastname: Blickenstaff
authors.forename: Thu-Thuy
authors.initials: TT
authors.lastname: Tran
authors.forename: Jason
authors.initials: J
authors.lastname: Abbott
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.forename: Shaohua
authors.initials: S
authors.lastname: Zhao
mesh_terms: D000818:Animals; D015373:Bacterial Typing Techniques; D002522:Chlorocebus aethiops; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D054308:Enteropathogenic Escherichia coli / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D004847:Epithelial Cells / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008460:Meat / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012703:Serotyping; D022603:Shiga Toxins / Q000235:genetics*; D054323:Shiga-Toxigenic Escherichia coli / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D014481:United States; D014709:Vero Cells; D037521:Virulence Factors / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D022603:Shiga Toxins; D037521:Virulence Factors