Molecular mechanisms of ethanol-induced pathogenesis revealed by RNA-sequencing

PLoS Pathogens

Volumn 6, Issue 4, 2010, Pages 1-14

  Camarena, Laura ^a,b   Bruno, Vincent ^a   Euskirchen, Ghia ^a,c   Poggio, Sebastian ^a   Snyder, Michael ^a,c  

^a YALE UNIVERSITY   (United States)

^b UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICO   (Mexico)

^c STANFORD UNIVERSITY SCHOOL OF MEDICINE   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ALCOHOL; HEAT SHOCK PROTEIN 40; HEAT SHOCK PROTEIN 70; HEAT SHOCK PROTEIN 90; MESSENGER RNA; PHOSPHOLIPASE C; BACTERIAL RNA; CENTRAL DEPRESSANT AGENT;

ACINETOBACTER BAUMANNII; ARTICLE; BACTERIAL STRAIN; BACTERIAL VIRULENCE; CELL DAMAGE; CONTROLLED STUDY; DELETION MUTANT; DOWN REGULATION; ENZYME RELEASE; GENE EXPRESSION; GENE IDENTIFICATION; GENE LOCATION; GENE SEQUENCE; NONHUMAN; NUCLEOTIDE SEQUENCE; REGULATORY MECHANISM; RNA ANALYSIS; RNA SEQUENCE; SEQUENCE HOMOLOGY; UPREGULATION; ACINETOBACTER INFECTION; BIOSYNTHESIS; CELL LINE; DRUG EFFECT; GENE EXPRESSION PROFILING; GENE EXPRESSION REGULATION; GENETICS; HUMAN; METABOLISM; PATHOGENICITY; PATHOLOGY; REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION; VIRULENCE;

ACINETOBACTER BAUMANNII; BACTERIA (MICROORGANISMS); CAENORHABDITIS ELEGANS; DICTYOSTELIUM DISCOIDEUM;

ACINETOBACTER BAUMANNII; ACINETOBACTER INFECTIONS; CELL LINE; CENTRAL NERVOUS SYSTEM DEPRESSANTS; ETHANOL; GENE EXPRESSION; GENE EXPRESSION PROFILING; GENE EXPRESSION REGULATION, BACTERIAL; HUMANS; REVERSE TRANSCRIPTASE POLYMERASE CHAIN REACTION; RNA, BACTERIAL; TYPE C PHOSPHOLIPASES; VIRULENCE;

EID: 77954038036     PISSN: 15537366     EISSN: 15537374     Source Type: Journal    
DOI: 10.1371/journal.ppat.1000834     Document Type: Article

References (101)

1. Baumann P, Doudoroff M, Stanier RY (1968) A study of the Moraxella group. II. Oxidative-negative species (genus Acinetobacter). J Bacteriol 95: 1520-1541.
2. Juni E (1978) Genetics and physiology of Acinetobacter. Annu Rev Microbiol 32: 349-371.
3. Waltermann M, Stoveken T, Steinbuchel A (2007) Key enzymes for biosynthesis of neutral lipid storage compounds in prokaryotes: properties, function and occurrence of wax ester synthases/acyl-CoA: diacylglycerol acyltransferases. Biochimie 89: 230-242.
4. Fagon JY, Chastre J, Domart Y, Trouillet JL, Gibert C (1996) Mortality due to ventilator-associated pneumonia or colonization with Pseudomonas or Acinetobacter species: assessment by quantitative culture of samples obtained by a protected specimen brush. Clin Infect Dis 23: 538-542.
5. Metan G, Alp E, Aygen B, Sumerkan B (2007) Acinetobacter baumannii meningitis in post-neurosurgical patients: clinical outcome and impact of carbapenem resistance. J Antimicrob Chemother 60: 197-199.
6. Wisplinghoff H, Bischoff T, Tallent SM, Seifert H, Wenzel RP, et al. (2004) Nosocomial bloodstream infections in US hospitals: analysis of 24,179 cases from a prospective nationwide surveillance study. Clin Infect Dis 39: 309-317.
7. Seifert H, Strate A, Pulverer G (1995) Nosocomial bacteremia due to Acinetobacter baumannii. Clinical features, epidemiology, and predictors of mortality. Medicine (Baltimore) 74: 340-349.
8. Poirel L, Lebessi E, Heritier C, Patsoura A, Foustoukou M, et al. (2006) Nosocomial spread of OXA-58-positive carbapenem-resistant Acinetobacter baumannii isolates in a paediatric hospital in Greece. Clin Microbiol Infect 12: 1138-1141.
9. Dijkshoorn L, Nemec A, Seifert H (2007) An increasing threat in hospitals: multidrug-resistant Acinetobacter baumannii. Nat Rev Microbiol 5: 939-951.
10. Hujer KM, Hujer AM, Hulten EA, Bajaksouzian S, Adams JM, et al. (2006) Analysis of antibiotic resistance genes in multidrug-resistant Acinetobacter sp. isolates from military and civilian patients treated at the Walter Reed Army Medical Center. Antimicrob Agents Chemother 50: 4114-4123.
11. Tien HC, Battad A, Bryce EA, Fuller J, Mulvey M, et al. (2007) Multi-drug resistant Acinetobacter infections in critically injured Canadian forces soldiers. BMC Infect Dis 7: 95.
12. Knapp S, Wieland CW, Florquin S, Pantophlet R, Dijkshoorn L, et al. (2006) Differential roles of CD14 and toll-like receptors 4 and 2 in murine Acinetobacter pneumonia. Am J Respir Crit Care Med 173: 122-129.
13. Erridge C, Moncayo-Nieto OL, Morgan R, Young M, Poxton IR (2007) Acinetobacter baumannii lipopolysaccharides are potent stimulators of human monocyte activation via Toll-like receptor 4 signalling. J Med Microbiol 56: 165-171.
14. Choi CH, Lee EY, Lee YC, Park TI, Kim HJ, et al. (2005) Outer membrane protein 38 of Acinetobacter baumannii localizes to the mitochondria and induces apoptosis of epithelial cells. Cell Microbiol 7: 1127-1138.
15. Choi CH, Hyun SH, Lee JY, Lee JS, Lee YS, et al. (2008) Acinetobacter baumannii outer membrane protein A targets the nucleus and induces cytotoxicity. Cell Microbiol 10: 309-319.
16. Tomaras AP, Dorsey CW, Edelmann RE, Actis LA (2003) Attachment to and biofilm formation on abiotic surfaces by Acinetobacter baumannii: involvement of a novel chaperone-usher pili assembly system. Microbiology 149: 3473-3484.
17. Zimbler DL, Penwell WF, Gaddy JA, Menke SM, Tomaras AP, et al. (2009) Iron acquisition functions expressed by the human pathogen Acinetobacter baumannii. Biometals 22: 23-32.
18. Dorsey CW, Tomaras AP, Connerly PL, Tolmasky ME, Crosa JH, et al. (2004) The siderophore-mediated iron acquisition systems of Acinetobacter baumannii ATCC 19606 and Vibrio anguillarum 775 are structurally and functionally related. Microbiology 150: 3657-3667.
19. Mihara K, Tanabe T, Yamakawa Y, Funahashi T, Nakao H, et al. (2004) Identification and transcriptional organization of a gene cluster involved in biosynthesis and transport of acinetobactin, a siderophore produced by Acinetobacter baumannii ATCC 19606T. Microbiology 150: 2587-2597.
20. Smith MG, Gianoulis TA, Pukatzki S, Mekalanos JJ, Ornston LN, et al. (2007) New insights into Acinetobacter baumannii pathogenesis revealed by high-density pyrosequencing and transposon mutagenesis. Genes Dev 21: 601-614.
21. Vallenet D, Nordmann P, Barbe V, Poirel L, Mangenot S, et al. (2008) Comparative analysis of Acinetobacters: three genomes for three lifestyles. PLoS ONE 3: e1805. doi:10.1371/journal.pone.0001805.
22. Iacono M, Villa L, Fortini D, Bordoni R, Imperi F, et al. (2008) Whole-genome pyrosequencing of an epidemic multidrug-resistant Acinetobacter baumannii strain belonging to the European clone II group. Antimicrob Agents Chemother 52: 2616-2625.
23. Adams MD, Goglin K, Molyneaux N, Hujer KM, Lavender H, et al. (2008) Comparative genome sequence analysis of multidrug-resistant Acinetobacter baumannii. J Bacteriol 190: 8053-8064.
24. Smith MG, Des Etages SG, Snyder M (2004) Microbial synergy via an ethanoltriggered pathway. Mol Cell Biol 24: 3874-3884.
25. Wanner BL (1987) Phosphate regulation of gene expression in Escherichia coli. In: Neidhardt F, Ingraham JL, Low KB, Magasanik B, Schaechter M, Umbarger HE, eds. Escherichia coli and Salmonella: cellular and molecular biology. Washington, D.C.: American Society for Microbiology. Pp 1326-1333.
26. Lamarche MG, Wanner BL, Crepin S, Harel J (2008) The phosphate regulon and bacterial virulence: a regulatory network connecting phosphate homeostasis and pathogenesis. FEMS Microbiol Rev 32: 461-473.
27. Yura T, Nagai H, Mori H (1993) Regulation of the heat-shock response in bacteria. Annu Rev Microbiol 47: 321-350.
28. Lakhal F, Bury-Mone S, Nomane Y, Le Goic N, Paillard C, et al. (2008) DjlA, a membrane-anchored DnaJ-like protein, is required for cytotoxicity of clam pathogen Vibrio tapetis to hemocytes. Appl Environ Microbiol 74: 5750-5758.
29. Du Y, Lenz J, Arvidson CG (2005) Global gene expression and the role of sigma factors in Neisseria gonorrhoeae in interactions with epithelial cells. Infect Immun 73: 4834-4845.
30. Lin SN, Ayada K, Zhao Y, Yokota K, Takenaka R, et al. (2005) Helicobacter pylori heat-shock protein 60 induces production of the pro-inflammatory cytokine IL8 in monocytic cells. J Med Microbiol 54: 225-233.
31. Hinode D, Yoshioka M, Tanabe S, Miki O, Masuda K, et al. (1998) The GroEL-like protein from Campylobacter rectus: immunological characterization and interleukin-6 and -8 induction in human gingival fibroblast. FEMS MicrobiolLett 167: 1-6.
32. Marioni JC, Mason CE, Mane SM, Stephens M, Gilad Y (2008) RNA-seq: an assessment of technical reproducibility and comparison with gene expression arrays. Genome Res 18: 1509-1517.
33. Fu X, Fu N, Guo S, Yan Z, Xu Y, et al. (2009) Estimating accuracy of RNASeq and microarrays with proteomics. BMC Genomics 10: 161.
34. Kornberg HL (1966) The role and control of the glyoxylate cycle in Escherichia coli. Biochem J 99: 1-11.
35. Kornberg HL, Krebs HA (1957) Synthesis of cell constituents from C2-units by a modified tricarboxylic acid cycle. Nature 179: 988-991.
36. Arndt A, Auchter M, Ishige T, Wendisch VF, Eikmanns BJ (2008) Ethanol catabolism in Corynebacterium glutamicum. J Mol Microbiol Biotechnol 15: 222-233.
37. Gerstmeir R, Wendisch VF, Schnicke S, Ruan H, Farwick M, et al. (2003) Acetate metabolism and its regulation in Corynebacterium glutamicum. J Biotechnol 104: 99-122.
38. Wolfe AJ (2005) The acetate switch. Microbiol Mol Biol Rev 69: 12-50.
39. Oh MK, Rohlin L, Kao KC, Liao JC (2002) Global expression profiling of acetate-grown Escherichia coli. J Biol Chem 277: 13175-13183.
40. Kakuda H, Hosono K, Shiroishi K, Ichihara S (1994) Identification and characterization of the ackA (acetate kinase A)-pta (phosphotransacetylase) operon and complementation analysis of acetate utilization by an ackA-pta deletion mutant of Escherichia coli. J Biochem 116: 916-922.
41. Reinscheid DJ, Schnicke S, Rittmann D, Zahnow U, Sahm H, et al. (1999) Cloning, sequence analysis, expression and inactivation of the Corynebacterium glutamicum pta-ack operon encoding phosphotransacetylase and acetate kinase. Microbiology 145(Pt 2): 503-513.
42. Serrano JA, Camacho M, Bonete MJ (1998) Operation of glyoxylate cycle in halophilic archaea: presence of malate synthase and isocitrate lyase in Haloferax volcanii. FEBS Lett 434: 13-16.
43. Loh WH, Randles CI, Sharp WR, Miller RH (1984) Intermediary carbon metabolism of Azospirillum brasilense. J Bacteriol 158: 264-268.
44. Molina I, Pellicer MT, Badia J, Aguilar J, Baldoma L (1994) Molecular characterization of Escherichia coli malate synthase G. Differentiation with the malate synthase A isoenzyme. Eur J Biochem 224: 541-548.
45. Ornston LN, Ornston MK (1969) Regulation of glyoxylate metabolism in Escherichia coli K-12. J Bacteriol 98: 1098-1108.
46. Cozzone AJ (1998) Regulation of acetate metabolism by protein phosphorylation in enteric bacteria. Annu Rev Microbiol 52: 127-164.
47. Sauer U, Eikmanns BJ (2005) The PEP-pyruvate-oxaloacetate node as the switch point for carbon flux distribution in bacteria. FEMS Microbiol Rev 29: 765-794.
48. Fleck CB, Brock M (2009) Re-characterisation of Saccharomyces cerevisiae Ach1p: fungal CoA-transferases are involved in acetic acid detoxification. Fungal Genet Biol 46: 473-485.
49. van der Rest ME, Frank C, Molenaar D (2000) Functions of the membraneassociated and cytoplasmic malate dehydrogenases in the citric acid cycle of Escherichia coli. J Bacteriol 182: 6892-6899.
50. Molenaar D, van der Rest ME, Drysch A, Yucel R (2000) Functions of the membrane-associated and cytoplasmic malate dehydrogenases in the citric acid cycle of Corynebacterium glutamicum. J Bacteriol 182: 6884-6891.
51. Itoh T, Matsuda H, Mori H (1999) Phylogenetic analysis of the third hsp70 homolog in Escherichia coli; a novel member of the Hsc66 subfamily and its possible co-chaperone. DNA Res 6: 299-305.
52. Kluck CJ, Patzelt H, Genevaux P, Brehmer D, Rist W, et al. (2002) Structurefunction analysis of HscC, the Escherichia coli member of a novel subfamily of specialized Hsp70 chaperones. J Biol Chem 277: 41060-41069.
53. Cipak A, Jaganjac M, Tehlivets O, Kohlwein SD, Zarkovic N (2008) Adaptation to oxidative stress induced by polyunsaturated fatty acids in yeast. Biochim Biophys Acta 1781: 283-287.
54. Allakhverdiev SI, Kinoshita M, Inaba M, Suzuki I, Murata N (2001) Unsaturated fatty acids in membrane lipids protect the photosynthetic machinery against salt-induced damage in Synechococcus. Plant Physiol 125: 1842-1853.
55. Alexandre H, Rousseaux I, Charpentier C (1994) Ethanol adaptation mechanisms in Saccharomyces cerevisiae. Biotechnol Appl Biochem 20(Pt 2): 173-183.
56. Zhang YM, Rock CO (2008) Membrane lipid homeostasis in bacteria. Nat Rev Microbiol 6: 222-233.
57. Marchand I, Damier-Piolle L, Courvalin P, Lambert T (2004) Expression of the RND-type efflux pump AdeABC in Acinetobacter baumannii is regulated by the AdeRS two-component system. Antimicrob Agents Chemother 48: 3298-3304.
58. Bina XR, Lavine CL, Miller MA, Bina JE (2008) The AcrAB RND efflux system from the live vaccine strain of Francisella tularensis is a multiple drug efflux system that is required for virulence in mice. FEMS Microbiol Lett 279: 226-233.
59. O'Toole R, Williams HD (2003) Universal stress proteins and Mycobacterium tuberculosis. Res Microbiol 154: 387-392.
60. Kvint K, Nachin L, Diez A, Nystrom T (2003) The bacterial universal stress protein: function and regulation. Curr Opin Microbiol 6: 140-145.
61. Nachin L, Nannmark U, Nystrom T (2005) Differential roles of the universal stress proteins of Escherichia coli in oxidative stress resistance, adhesion, and motility. J Bacteriol 187: 6265-6272.
62. Nonaka G, Blankschien M, Herman C, Gross CA, Rhodius VA (2006) Regulon and promoter analysis of the E. coli heat-shock factor, sigma32, reveals a multifaceted cellular response to heat stress. Genes Dev 20: 1776-1789.
63. Thomas J, Cronan JE (2005) The enigmatic acyl carrier protein phosphodiesterase of Escherichia coli: genetic and enzymological characterization. J Biol Chem 280: 34675-34683.
64. Audia JP, Patton MC, Winkler HH (2008) DNA microarray analysis of the heat shock transcriptome of the obligate intracytoplasmic pathogen Rickettsia prowazekii. Appl Environ Microbiol 74: 7809-7812.
65. Slamti L, Livny J, Waldor MK (2007) Global gene expression and phenotypic analysis of a Vibrio cholerae rpoH deletion mutant. J Bacteriol 189: 351-362.
66. Qin JH, Sheng YY, Zhang ZM, Shi YZ, He P, et al. (2006) Genome-wide transcriptional analysis of temperature shift in L. interrogans serovar lai strain 56601. BMC Microbiol 6: 51.
67. Green HA, Donohue TJ (2006) Activity of Rhodobacter sphaeroides RpoHII, a second member of the heat shock sigma factor family. J Bacteriol 188: 5712-5721.
68. Asadulghani, Suzuki Y, Nakamoto H (2003) Light plays a key role in the modulation of heat shock response in the cyanobacterium Synechocystis sp PCC 6803. Biochem Biophys Res Commun 306: 872-879.
69. Martinez-Salazar JM, Sandoval-Calderon M, Guo X, Castillo-Ramirez S, Reyes A, et al. (2009) The Rhizobium etli RpoH1 and RpoH2 sigma factors are involved in different stress responses. Microbiology 155: 386-397.
70. Gross C, Neidhardt FC, Curtiss R, III, Ingraham JL, Lin ECC, et al. (1996) Function and regulation of the heat shock proteins. Eschericha coli and Salmonella: cellular and Molecular Biology. Washington, D.C.: ASM Press. pp 1382-1399.
71. Gur E, Sauer RT (2008) Recognition of misfolded proteins by Lon, a AAA(+) protease. Genes Dev 22: 2267-2277.
72. Shelburne CE, Coopamah MD, Sweier DG, An FY, Lopatin DE (2007) HtpG, the Porphyromonas gingivalis HSP-90 homologue, induces the chemokine CXCL8 in human monocytic and microvascular vein endothelial cells. Cell Microbiol 9: 1611-1619.
73. Xu H, Lee HY, Ahn J (2008) Cross-protective effect of acid-adapted Salmonella enterica on resistance to lethal acid and cold stress conditions. Lett Appl Microbiol 47: 290-297.
74. Gunasekera TS, Csonka LN, Paliy O (2008) Genome-wide transcriptional responses of Escherichia coli K-12 to continuous osmotic and heat stresses. J Bacteriol 190: 3712-3720.
75. Koga T, Sakamoto F, Yamoto A, Takumi K (1999) Acid adaptation induces cross-protection against some environmental stresses in Vibrio parahaemolyticus. J Gen Appl Microbiol 45: 155-161.
76. Volker U, Mach H, Schmid R, Hecker M (1992) Stress proteins and crossprotection by heat shock and salt stress in Bacillus subtilis. J Gen Microbiol 138: 2125-2135.
77. Songer JG (1997) Bacterial phospholipases and their role in virulence. Trends Microbiol 5: 156-161.
78. Korbsrisate S, Tomaras AP, Damnin S, Ckumdee J, Srinon V, et al. (2007) Characterization of two distinct phospholipase C enzymes from Burkholderia pseudomallei. Microbiology 153: 1907-1915.
79. Poussin MA, Leitges M, Goldfine H (2009) The ability of Listeria monocytogenes PI-PLC to facilitate escape from the macrophage phagosome is dependent on host PKCbeta. Microb Pathog 46: 1-5.
80. Anstey NM, Currie BJ, Hassell M, Palmer D, Dwyer B, et al. (2002) Community-acquired bacteremic Acinetobacter pneumonia in tropical Australia is caused by diverse strains of Acinetobacter baumannii, with carriage in the throat in at-risk groups. J Clin Microbiol 40: 685-686.
81. Chen M-Z, Hsueh Po-Ren, Lee Li-Na, Yu C-J, Yang P-C, Luh K-T (2001) Severe Community-Acquired Pneumonia due to Acinetobacter baumannii. Chest 120: 1072-1077.
82. Falagas ME, Karveli EA, Kelesidis I, Kelesidis T (2007) Community-acquired Acinetobacter infections. Eur J Clin Microbiol Infect Dis 26: 857-868.
83. Bailey KL, Wyatt TA, Romberger DJ, Sisson JH (2009) Alcohol functionally upregulates Toll-like receptor 2 in airway epithelial cells. Alcohol Clin Exp Res 33: 499-504.
84. Vulic M, Kolter R (2002) Alcohol-induced delay of viability loss in stationaryphase cultures of Escherichia coli. J Bacteriol 184: 2898-2905.
85. Ochsner UA, Snyder A, Vasil AI, Vasil ML (2002) Effects of the twin-arginine translocase on secretion of virulence factors, stress response, and pathogenesis. Proc Natl Acad Sci USA 99: 8312-8317.
86. Rossier O, Cianciotto NP (2005) The Legionella pneumophila tatB gene facilitates secretion of phospholipase C, growth under iron-limiting conditions, and intracellular infection. Infect Immun 73: 2020-2032.
87. Lee JC, Oh JY, Kim KS, Jeong YW, Park JC, et al. (2001) Apoptotic cell death induced by Acinetobacter baumannii in epithelial cells through caspase-3 activation. APMIS 109: 679-684.
88. Titball RW (1993) Bacterial phospholipases C. Microbiol Rev 57: 347-366.
89. Vasil ML, Stonehouse MJ, Vasil AI, Wadsworth SJ, Goldfine H, et al. (2009) A complex extracellular sphingomyelinase of Pseudomonas aeruginosa inhibits angiogenesis by selective cytotoxicity to endothelial cells. PLoS Pathog 5: e1000420. doi:10.1371/journal.ppat.1000420.
90. Camilli A, Tilney LG, Portnoy DA (1993) Dual roles of plcA in Listeria monocytogenes pathogenesis. Mol Microbiol 8: 143-157.
91. Marquis H, Doshi V, Portnoy DA (1995) The broad-range phospholipase C and a metalloprotease mediate listeriolysin O-independent escape of Listeria monocytogenes from a primary vacuole in human epithelial cells. Infect Immun 63: 4531-4534.
92. Grundling A, Gonzalez MD, Higgins DE (2003) Requirement of the Listeria monocytogenes broad-range phospholipase PC-PLC during infection of human epithelial cells. J Bacteriol 185: 6295-6307.
93. Quandt J, Hynes MF (1993) Versatile suicide vectors which allow direct selection for gene replacement in gram-negative bacteria. Gene 127: 15-21.
94. Hunger M, Schmucker R, Kishan V, Hillen W (1990) Analysis and nucleotide sequence of an origin of DNA replication in Acinetobacter calcoaceticus and its use for Escherichia coli shuttle plasmids. Gene 87: 45-51.
95. Spaink HP, Okker RJH, Wijffelman CA, Pees E, Lugtenberg BJJ (1987) Promoters in the nodulation region of the Rhizobium leguminosarum symbiotic plasmid pRL1JI. Plant Mol Biol 9: 27-39.
96. Ausubel FM, Brent R, Kingston RE, Moore DD, Seidman JG, et al. (1987) Current Protocols in Molecular Biology. New York: John Wiley.
97. Dorsey CW, Tomaras AP, Actis LA (2002) Genetic and phenotypic analysis of Acinetobacter baumannii insertion derivatives generated with a transposome system. Appl Environ Microbiol 68: 6353-6360.
98. Rozen S, Skaletsky H (2000) Primer3 on the WWW for general users and for biologist programmers. Methods Mol Biol 132: 365-386.
99. Livak KJ, Schmittgen TD (2001) Analysis of relative gene expression data using real-time quantitative PCR and the 2(-Delta Delta C(T)) Method. Methods 25: 402-408.
100. Miller J (1972) Experiments in molecular genetics. Cold Spring Harbor, N.Y.: Cold Spring Harbor Laboratory.
101. Paton JC, Rogers TJ, Morona R, Paton AW (2001) Oral administration of formaldehyde-killed recombinant bacteria expressing a mimic of the Shiga toxin receptor protects mice from fatal challenge with Shiga-toxigenic Escherichia coli. Infect Immun 69: 1389-1393.