title: Distinct transcriptional profiles and phenotypes exhibited by Escherichia coli O157:H7 isolates related to the 2006 spinach-associated outbreak.
abstract: In 2006, a large outbreak of Escherichia coli O157:H7 was linked to the consumption of ready-to-eat bagged baby spinach in the United States. The likely sources of preharvest spinach contamination were soil and water that became contaminated via cattle or feral pigs in the proximity of the spinach fields. In this study, we compared the transcriptional profiles of 12 E. coli O157:H7 isolates that possess the same two-enzyme pulsed-field gel electrophoresis (PFGE) profile and are related temporally or geographically to the above outbreak. These E. coli O157:H7 isolates included three clinical isolates, five isolates from separate bags of spinach, and single isolates from pasture soil, river water, cow feces, and a feral pig. The three clinical isolates and two spinach bag isolates grown in cultures to stationary phase showed decreased expression of many σ(S)-regulated genes, including gadA, osmE, osmY, and katE, compared with the soil, water, cow, feral pig, and the other three spinach bag isolates. The decreased expression of these σ(S)-regulated genes was correlated with the decreased resistance of the isolates to acid stress, osmotic stress, and oxidative stress but increases in scavenging ability. We also observed that intraisolate variability was much more pronounced among the clinical and spinach isolates than among the environmental isolates. Together, the transcriptional and phenotypic differences of the spinach outbreak isolates of E. coli O157:H7 support the hypothesis that some variants within the spinach bag retained characteristics of the preharvest isolates, whereas other variants with altered gene expression and phenotypes infected the human host.
authors.affiliation: Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California, USA. craig.parker@ars.usda.gov
authors.forename: Craig T
authors.initials: CT
authors.lastname: Parker
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Kyle
authors.forename: Steven
authors.initials: S
authors.lastname: Huynh
authors.forename: Michelle Q
authors.initials: MQ
authors.lastname: Carter
authors.forename: Maria T
authors.initials: MT
authors.lastname: Brandl
authors.forename: Robert E
authors.initials: RE
authors.lastname: Mandrell
mesh_terms: D000143:Acids / Q000633:toxicity; D000818:Animals; D002417:Cattle; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D005243:Feces / Q000382:microbiology; D005517:Foodborne Diseases / Q000453:epidemiology / Q000382:microbiology*; D005838:Genotype; D006801:Humans; D008969:Molecular Sequence Data; D058889:Molecular Typing; D009997:Osmotic Pressure; D018384:Oxidative Stress; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D018724:Spinacia oleracea / Q000382:microbiology*; D013312:Stress, Physiological; D013552:Swine; D059467:Transcriptome; D014481:United States / Q000453:epidemiology
chemical_list: D000143:Acids
references.citation: J Bacteriol. 2009 Mar;191(6):1868-77
references.pmid: 19114477
references.citation: Infect Immun. 2005 Aug;73(8):4993-5003
references.pmid: 16041014
references.citation: MMWR Morb Mortal Wkly Rep. 2006 Sep 29;55(38):1045-6
references.pmid: 17008868
references.citation: Infect Immun. 2000 May;68(5):2518-24
references.pmid: 10768939
references.citation: Appl Environ Microbiol. 2011 Jun;77(11):3685-95
references.pmid: 21478320
references.citation: Proc Natl Acad Sci U S A. 2008 Mar 25;105(12):4868-73
references.pmid: 18332430
references.citation: Infect Immun. 1996 Jul;64(7):2808-11
references.pmid: 8698513
references.citation: J Bacteriol. 2005 Mar;187(5):1591-603
references.pmid: 15716429
references.citation: ISME J. 2011 Feb;5(2):262-73
references.pmid: 20686510
references.citation: Microbiology (Reading). 2008 Nov;154(Pt 11):3518-3528
references.pmid: 18957604
references.citation: Nucleic Acids Res. 1997 Sep 1;25(17):3389-402
references.pmid: 9254694
references.citation: Infect Immun. 2009 Sep;77(9):3713-21
references.pmid: 19564389
references.citation: PLoS One. 2007 Nov 14;2(11):e1159
references.pmid: 18174909
references.citation: Microbiology (Reading). 2010 Feb;156(Pt 2):408-419
references.pmid: 19892762
references.citation: Appl Environ Microbiol. 2010 Mar;76(5):1375-87
references.pmid: 20061451
references.citation: J Bacteriol. 1990 Jun;172(6):3191-200
references.pmid: 2160940
references.citation: J Bacteriol. 2002 Feb;184(3):806-11
references.pmid: 11790751
references.citation: Appl Environ Microbiol. 1996 May;62(5):1822-4
references.pmid: 8633882
references.citation: J Food Prot. 2009 Mar;72(3):503-9
references.pmid: 19343937
references.citation: Infect Immun. 1993 Jan;61(1):364-7
references.pmid: 8418063
references.citation: Nucleic Acids Res. 2001 Jul 15;29(14):2994-3005
references.pmid: 11452024
references.citation: BMC Genomics. 2009 Aug 03;10:349
references.pmid: 19650909
references.citation: J Bacteriol. 2007 Mar;189(6):2350-8
references.pmid: 17158684
references.citation: PLoS Pathog. 2010 Aug 26;6(8):e1001078
references.pmid: 20865122
references.citation: Appl Environ Microbiol. 2010 Jan;76(1):60-8
references.pmid: 19880650
references.citation: J Bacteriol. 2004 Sep;186(17):5614-20
references.pmid: 15317765
references.citation: BMC Microbiol. 2009 Jun 03;9:118
references.pmid: 19493358
references.citation: Appl Environ Microbiol. 2006 Jul;72(7):4978-86
references.pmid: 16820496
references.citation: MMWR Morb Mortal Wkly Rep. 2009 Jun 12;58(22):609-15
references.pmid: 19521332
references.citation: Science. 1996 Nov 15;274(5290):1208-11
references.pmid: 8895473
references.citation: Emerg Infect Dis. 2005 Dec;11(12):1955-7
references.pmid: 16485489
references.citation: J Bacteriol. 1997 Apr;179(7):2141-6
references.pmid: 9079897
references.citation: Proc Natl Acad Sci U S A. 1998 Dec 8;95(25):14863-8
references.pmid: 9843981
references.citation: Mol Microbiol. 2003 Sep;49(6):1605-14
references.pmid: 12950924
references.citation: Appl Environ Microbiol. 1995 May;61(5):2037-9
references.pmid: 7646045
references.citation: Appl Environ Microbiol. 2008 Sep;74(17):5285-9
references.pmid: 18641153
references.citation: J Bacteriol. 1990 May;172(5):2779-81
references.pmid: 2185233
references.citation: J Bacteriol. 1999 Sep;181(17):5250-6
references.pmid: 10464194
references.citation: Mol Microbiol. 2003 Jan;47(1):103-18
references.pmid: 12492857
references.citation: J Bacteriol. 1994 Mar;176(6):1729-37
references.pmid: 8132468
references.citation: J Bacteriol. 2007 Apr;189(7):2759-68
references.pmid: 17259322
references.citation: PLoS Genet. 2009 Oct;5(10):e1000671
references.pmid: 19798444