Physiologic and molecular markers for detection of shiga toxin-producing Escherichia coli serotype O26 strains

Foodborne Pathogens and Disease

Volumn 3, Issue 2, 2006, Pages 163-177

  Murinda, Shelton E ^a   Oliver, Stephen P ^b  

^a CALIFORNIA STATE POLYTECHNIC UNIVERSITY   (United States)

^b UNIVERSITY OF TENNESSEE   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

SHIGA TOXIN;

BACTERIUM IDENTIFICATION; BACTERIUM ISOLATE; DIARRHEAGENIC ESCHERICHIA COLI; ESCHERICHIA COLI; GENETIC ANALYSIS; GENETIC MARKER; GENETIC VARIABILITY; PATHOGENESIS; PEER REVIEW; PHENOTYPE; PRIORITY JOURNAL; PUBLIC HEALTH; REVIEW;

ANIMALS; ESCHERICHIA COLI; ESCHERICHIA COLI INFECTIONS; FOOD MICROBIOLOGY; GENETIC MARKERS; HUMANS; PHENOTYPE; PUBLIC HEALTH; SEROTYPING; SHIGA TOXINS;

ESCHERICHIA COLI;

EID: 33745057482     PISSN: 15353141     EISSN: None     Source Type: Journal    
DOI: 10.1089/fpd.2006.3.163     Document Type: Review

References (101)

1. Adu-Bobie, J., G. Frankel, C. Bain, et al. 1998. Detection of intimins alpha, beta, gamma, and delta, four intimin derivatives expressed by attaching and effacing microbial pathogens. J. Clin. Microbiol. 36:662-668.
2. Anderson, R.C., S.A. Buckley, L.F. Kubena, et al. 2000. Bactericidal effect of sodium chlorate on Escherichia coli O157:H7 and Salmonella typhimurium DT104 in rumen contents in vitro. J. Food Prot. 63:1038-1042.
3. Armstrong G.D., P.C. Rowe, P. Goodyer, et al. 1995. A phase I study of chemically synthesized verotoxin (Shiga-like toxin) Pk-trisaccharide receptors attached to chromosorb for preventing hemolytic-uremic syndrome. J. Infect. Dis. 171:1042-1045.
4. Banatvala, N., P.M. Griffin, K.D. Greene, et al. 2001. The United States National Prospective Hemolytic Uremic Syndrome Study: microbiologic, serologic, clinical, and epidemiologic findings. J. Infect. Dis. 183:1063-1070.
5. Baylis, C.L., S. MacPhee, A.J. Robinson, et al. 2004. Survival of Escherichia coli O157:H7, O111:H- and O26:H11 in artificially contaminated chocolate and confectionery products. Int. J. Food Microbiol. 96:35-48.
6. Benson, A. S. 1995. Control of Communicable Diseases Manual, 16th ed. United Book Press, Baltimore, MD.
7. Bettelheim, K.A. 1998. Studies of Escherichia coli cultured on Rainbow Agar O157 with particular reference to enterohaemorrhagic Escherichia coli (EHEC). Microbiol. Immunol. 42:265-269.
8. Bettelheim, K.A. 2000. Role of non-O157 VTEC. Symp. Ser. Soc. Appl. Microbiol. 29:38S-50S.
9. Bettelheim, K.A., J.C. Bensink, and H.S. Tambunan. 2000. Serotypes of verotoxin-producing (Shiga toxin-producing) Escherichia coli isolated from healthy sheep. Comp. Immunol. Microbiol. Infect. Dis. 23:1-7.
10. Beutin, L., M.A. Montenegro, I. Orskov, et al. 1989. Close association of verotoxin (Shiga-like toxin) production with enterohemolysin production in strains of Escherichia coli. J. Clin. Microbiol. 27:2559-2564.
11. Beutin, L., S. Zimmermann, and K. Gleier. 1996. Rapid detection and isolation of Shiga-like toxin (verocytotoxin)-producing Escherichia coli by direct testing of individual enterohemolytic colonies from washed sheep blood agar plates in the VTEC-RPLA assay. J. Clin. Microbiol. 34:2812-2814.
12. Bielaszewska, M., J. Janda, K. Blahova, et al. 1996. Veocytotoxin- producing Escherichia coli in children with hemolytic uremic syndrome in the Czech Republic. Clin. Nephrol. 46:42-44.
13. Blanco, J.E., M. Blanco, J. Blanco, et al. 1996. O serogroups, biotypes, and eae genes in Escherichia coli strains isolated from diarrheic and healthy rabbits. J. Clin. Microbiol. 34:3101-3107.
14. Borie, C.F., Z. Monreal, J. Martinez, et al. 1997. Detection and characterization of enterohaemorrhagic Escherichia coli in slaughtered cattle. Zentralbl. Veterinarmed. B 44:273-279.
15. Brashears, M.M., M.L. Galyean, G.H. Loneragan, et al. 2003. Prevalence of Escherichia coli O157:H7 and performance by beef feedlot cattle given Lactobacillus direct-fed microbials. J. Food Prot. 66:748-754.
16. Brooks, H.J., K.A. Bettelheim, B. Todd, et al. 1997. Non-O157 Vero cytotoxin producing Escherichia coli: aetiological agents of diarrhoea in children in Dunedin, New Zealand. Comp. Immunol. Microbiol. Infect. Dis. 20:163-170.
17. Caprioli, A., A.E. Tozzi, G. Rizzoni, et al. 1997. Non-O157 Shiga toxin-producing Escherichia coli infections in Europe [Letter]. Emerg. Infect. Dis. 3:578-579.
18. Cartter, M.W.E. 2001. Shiga toxin-producing Escherichia coli in Connecticut, 2000-2001. Connecticut Epidemiol. 21:15-16.
19. China, B., F. Goffaux, V. Pirson, et al. 1999. Comparison of eae, tir, espA and espB genes of bovine and human attaching and effacing Escherichia coli by multiplex polymerase chain reaction. FEMS Microbiol. Lett. 178:177-182.
20. Dean-Nystrom, E.A., L.J. Gansheroff, M. Mills, et al. 2002. Vaccination of pregnant dams with intimin (O157) protects suckling piglets from Escherichia coli O157:H7 infection. Infect. Immun. 70:2414-2418.
21. De Boer, E., and A.E. Heuvelink. 2000. Methods for the detection and isolation of Shiga toxin-producing Escherichia coli. Symp. Ser. Soc. Appl. Microbiol. 29:1335-1435.
22. DebRoy, C., E. Roberts, J. Kundrat, et al. 2004. Detection of Escherichia coli serogroups O26 and O113 by PCR amplification of the wzx and wzy genes. Appl. Environ. Microbiol. 70:1830-1832.
23. Diez-Gonzalez, F., T.R. Callaway, M.G. Kizoulis, et al. 1998. Grain feeding and the dissemination of acid-resistant Escherichia coli from cattle. Science 281:1666-1668.
24. Dorn, C.R., D.H. Francis, E.J. Angrick, et al. 1993. Characteristics of Vero cytotoxin producing Escherichia coli associated with intestinal colonization and diarrhea in calves. Vet. Microbiol. 36:149-159.
25. D'Souza, J., L. Wang, and P. Reeves. 2002. Sequence of the Escherichia coli O26 O antigen gene cluster and identification of O26 specific genes. Gene 297:123-127.
26. Duncan, S.H., I.R. Booth, I.R. Flint, et al. 2000. The potential for the control of Escherichia coli in farm animals. Symp. Ser. Soc. Appl. Microbiol. 29:157S-165S.
27. Elliott, E.J., R.M. Robins-Browne, E.V. O'Loughlin, et al. 2001. Nationwide study of haemolytic uraemic syndrome: clinical, microbiological, and epidemiological features. Arch. Dis. Child. 85:125-131.
28. Farina, C., A. Goglio, G. Conedera, et al. 1996. Antimicrobial susceptibility of Escherichia coli O157 and other enterohaemorrhagic Escherichia coli isolated in Italy. Eur. J. Clin. Microbiol. Infect. Dis. 15:351-353.
29. Fey, P.D., R.S. Wickert, M.E. Rupp, et al. 2000. Prevalence of non-O157:H7 Shiga toxin-producing Escherichia coli in diarrheal stool samples from Nebraska. Emerg. Infect. Dis. 6:530-533.
30. Fratamico, P.M., L.K. Bagi, and T. Pepe. 2000. A multiplex polymerase chain reaction assay for rapid detection and identification of Escherichia coli O157:H7 in foods and bovine feces. J. Food Prot. 63:1032-1037.
31. FSIS/USDA. 1996. Pathogen reduction: hazard analysis and critical control point (HACCP) systems: final rule. Food Safety Inspection Service, United States Department of Agriculture. Fed. Reg. 61:38805-38989.
32. Fukushima, H., and M. Gomyoda. 1999. An effective, rapid and simple method for isolation of Shiga toxin-producing Escherichia coli O26, O111 and O157 from faeces and food samples. Zentralbl. Bakteriol. 289:415-428.
33. Fukushima, H., K. Hoshina, and M. Gomyoda. 1999. Long-term survival of Shiga toxin-producing Escherichia coli O26, O111, and O157 in bovine feces. Appl. Environ. Microbiol. 65:5177-5181.
34. Gansheroff, L.J., M.R. Wachtel, and A.D. O'Brien. 1999. Decreased adherence of enterohemorrhagic Escherichia coli to HEp-2 cells in the presence of antibodies that recognize the C-terminal region of intimin. Infect. Immun. 67:6409-6417.
35. Ghaem-Maghami, M., C.P. Simmons, S. Daniell, et al. 2001. Intimin-specific immune responses prevent bacterial colonization by the attaching-effacing pathogen Citrobacter rodentium. Infect. Immun. 69:5597-5605.
36. Grif, K., M.P. Dierich, H. Karch, et al. 1998. Strain-specific differences in the amount of Shiga toxin released from enterohemorrhagic Escherichia coli O157 following exposure to subinhibitory concentrations of antimicrobial agents. Eur. J. Clin. Microbiol. Infect. Dis. 17:761-766.
37. Griffin, P.M., and R.V. Tauxe. 1991. The epidemiology of infections caused by Escherichia coli O157:H7, other enterohemorrhagic E. coli, and the associated hemolytic uremic syndrome. Epidemiol. Rev. 13:60-98.
38. Guth, B.E.C., R.L. de Souza, and T.M.I. Vaz. 2002. First toxin-producing Escherichia coli isolate from a patient with hemolytic uremic syndrome, Brazil. Emerg. Infect. Dis. 8:535-536.
39. Harmon, B.G., C.A. Brown, S. Tkalcic, et al. 1999. Fecal shedding and rumen growth of Escherichia coli O157:H7 in fasted calves. J. Food Prot. 62:574-579.
40. Hiramatsu, R., M. Matsumoto, Y. Miwa, et al. 2002. Characterization of Shiga toxin-producing Escherichia coli O26 strains and establishment of selective isolation media for these strains. J. Clin. Microbiol. 40:922-925.
41. Hiruta, N., T. Murase, and N. Okamura. 2001. An outbreak of diarrhoea due to multiple antimicrobial-resistant Shiga toxin-producing Escherichia coli O26:H11 in a nursery. Epidemiol. Infect. 127:221-227.
42. th ed. AOAC International, Gaithersburg, MD, pp. 4.01-4.10.
43. Ikedo, M., O. Komatsu, Y. Hara-Kudo, et al. 2001. Development of chromogenic agar medium for isolation of enterohaemorrhagic Escherichia coli O26 [in Japanese]. English abstract available online: 〈www.ncbi.nlm.nih.gov/ htbin-post/Entrez/query?db=m&form=&dopt=&uid= 11357319〉. Accessed August 8, 2005.
44. Johnson, R.P., R.C. Clarke, J.B. Wilson, et al. 1996. Growing concerns and recent outbreaks involving non-O157:H7 serotypes of verotoxigenic Escherichia coli. J. Food Prot. 59:1112-1122.
45. Karch, H., S. Schubert, D. Zhang, et al. 1999. A genomic island, termed high-pathogenicity island, is present in certain non-O157 Shiga toxin-producing Escherichia coli clonal lineages. Infect. Immun. 67:5994-6001.
46. Karmali, M. A. 1989. Infection by verocytotoxin-producing Escherichia coli. Clin. Microbiol. Rev. 2:15-38.
47. Karmali, M.A., M. Petric, and M. Bielaszewska. 1999. Evaluation of a microplate latex agglutination method (Verotox-F assay) for detecting and characterizing verotoxins (Shiga toxins) in Escherichia coli. J. Clin. Microbiol. 37:396-399.
48. Kobayashi, H., J. Shimada, M. Nakazawa, et al. 2001. Prevalence and characteristics of Shiga toxin-producing Escherichia coli from healthy cattle in Japan. Appl. Environ. Microbiol. 67:484-689.
49. Kohler, B., H. Karch, and H. Schmidt. 2000. Antibacterials that are used as growth promoters in animal husbandry can affect the release of Shiga toxin-2-converting bacteriophages and Shiga toxin 2 from Escherichia coli strains. Microbiol. 146:1085-1090.
50. Konadu, E.Y., J.C. Parke, Jr., H.T. Tran, et al. 1998. Investigational vaccine for Escherichia coli O157: phase 1 study of O157 O-specific polysaccharide-Pseudomonas aeruginosa recombinant exoprotein A conjugates in adults. J. Infect. Dis. 177:383-387.
51. Konowalchuk, J., J.I. Speirs, and S. Stavric. 1977. Vero response to a cytotoxin of Escherichia coli. Infect. Immun. 18:775-779.
52. Kudva, I.T., C.W. Hunt, C.J. Williams, et al. 1997. Evaluation of dietary influences on Escherichia coli O157:H7 shedding by sheep. Appl. Environ. Microbiol. 63:3878-3886.
53. Kudva, I.T., S. Jelacic, P.I. Tarr, et al. 1999. Biocontrol of Escherichia coli O157 with O157-specific bacteriophages. Appl. Environ. Microbiol. 65:3767-3773.
54. Louie, M., S. Read, A.E. Simor, et al. 1998. Application of multiplex PCR for detection of non-O157 verocytotoxin-producing Escherichia coli in bloody stools: identification of serogroups O26 and O111. J. Clin. Microbiol. 36: 3375-3377.
55. Ludwig, K., M. Bitzan, S. Zimmermann, et al. 1996. Immune response to non-O157 Vero toxin-producing Escherichia coli in patients with hemolytic uremic syndrome. J. Infect. Dis. 174:1028-1039.
56. Magnuson, B.A., M. Davis, S. Rubele, et al. 2000. Ruminant gastrointestinal cell proliferation and clearance of Escherichia coli O157:H7. Infect. Immun. 7:3808-3814.
57. Mainil, J. 1999. Shiga/verocytotoxins and Shiga/verotoxigenic Escherichia coli in animals. Vet. Res. 1999. 30:235-257.
58. McMaster, C., E.A. Roch, G.A. Willshaw, et al. 2001. Verocytotoxin- producing Escherichia coli serotype O26:H11 outbreak in an Irish creche. Eur. J. Clin. Microbiol. Infect. Dis. 20:430-432.
59. Mead, P.S., L. Slutsker, V. Dietz, et al. 1999. Food-related illness and death in the United States. Emerg. Infect. Dis. 5:607-625.
60. Misselwitz, J., H. Karch, M. Bielazewska, et al. 2003. Cluster of hemolytic-uremic syndrome caused by Shiga toxin-producing Escherichia coli O26:H11. Pediatr. Infect. Dis. J. 22:349-354.
61. Murinda, S.E., R.F. Roberts, and R.A. Wilson. 1996. Evaluation of colicins for inhibitory activity against diarrheagenic Escherichia coli strains, including serotype O157:H7. Appl. Environ. Microbiol. 62:3196-3202.
62. Murinda, S.E., S.D. Batson, L.T. Nguyen, et al. 2004. Phenotypic and genetic markers for serotype-specific detection of Shiga toxin-producing Escherichia coli O26 strains from North America. Foodborne Pathog. Dis. 1:125-135.
63. Nataro, J.P., and J.B. Kaper. 1998. Diarrheagenic Escherichia coli. Clin. Microbiol. Rev. 11:142-201.
64. Novicki, T.J., J.A. Daly, S.L. Mottice, et al. 2000. Comparison of sorbitol MacConkey agar and a two-step method which utilizes enzyme-linked immunosorbent assay toxin testing and a chromogenic agar to detect and isolate enterohemorrhagic Escherichia coli. J. Clin. Microbiol. 38:547-551.
65. Ojeda, A., V. Prado, J. Martinez, et al. 1995. Sorbitol-negative phenotype among enterohemorrhagic Escherichia coli strains of different serotypes and from different sources. J. Clin. Microbiol. 33:2199-2201.
66. Oswald, E., H. Schmidt, S. Morabito, et al. 2000. Typing of intimin genes in human and animal enterohemorrhagic and enteropathogenic Escherichia coli: characterization of a new intimin variant. Infect. Immun. 68:64-71.
67. Park, C.H., K.M. Gates, N.M. Vandel, et al. 1996. Isolation of Shiga-like toxin producing Escherichia coli (O157 and non-O157) in a community hospital. Diagn. Microbiol. Infect. Dis. 26:69-72.
68. Paton, J.C., and A.W. Paton. 1998. Pathogenesis and diagnosis of Shiga toxin-producing Escherichia coli infections. Clin. Microbiol. Rev. 11:450-479.
69. Patterson, J.A., and K.M. Burkholder. 2003. Application of prebiotics and probiotics in poultry production. Poult. Sci. 82:627-631.
70. Peixoto, J.C., S.Y. Bando, J.A. Ordonez, et al. 2001. Genetic differences between Escherichia coli O26 strains isolated in Brazil and in other countries. FEMS Microbiol. Lett. 196:239-244.
71. Potter, A.A., S. Klashinsky, Y. Li, et al. 2004. Decreased shedding of Escherichia coli O157:H7 by cattle following vaccination with type III secreted proteins. Vaccine 22:362-369.
72. Read, S.C., R.C. Clarke, A. Martin, et al. 1992. Polymerase chain reaction for detection of verocytotoxigenic Escherichia coli isolated from animal and food sources. Mol. Cell Probes 6:153-161.
73. Ricotti, G.C., M.I. Buonomini, A. Merlitti, et al. 1994. A fatal case of hemorrhagic colitis, thrombocytopenia, and renal failure associated with verocytotoxin-producing, non-O157 Escherichia coli. Clin. Infect. Dis. 19:815-816.
74. Rivera-Betancourt, M., and J.E. Keen. 2000. Murine monoclonal antibodies specific for lipopolysaccharide of Escherichia coli O26 and O111. Appl. Environ. Microbiol. 66:4124-4127.
75. Safarikova, M., and I. Safarik. 2001. Immunomagnetic separation of Escherichia coli O26, O111 and O157 from vegetables. Lett. Appl. Microbiol. 33:36-39.
76. Sandhu, K.S., R.C. Clarke, K. McFadden, et al. 1996. Prevalence of the eaeA gene in verotoxigenic Escherichia coli strains from dairy cattle in Southwest Ontario. Epidemiol. Infect. 116:1-7.
77. Schamberger, G.P., R.L. Phillips, J.L. Jacobs, et al. 2004. Reduction of Escherichia coli O157:H7 populations in cattle by addition of colicin E7-producing E. coli to feed. Appl. Environ. Microbiol. 70:6053-6060.
78. Scheutz, F. 1997. EPEC revisited: more than half of Danish enteropathogenic E. coli (EPEC) strains O groups O26, O111 and O128 isolated 1959-1996 are actually VTEC [Online]. Available: (http://ecoli.bham.ac.uk/vtec/ issue1/vtecv41.html). Accessed August 8, 2005.
79. Schmidt, H., L. Beutin, and H. Kartch. 1995. Molecular analysis of the plasmid-encoded hemolysin of Escherichia coli O157:H7 strain EDL 933. Infect. Immun. 63:1055-1061.
80. Schmidt, H., C. Geitz, P. Tarr, et al. 1999. Non-O157:H7 pathogenic Shiga toxin-producing Escherichia coli: phenotypic and genetic profiling of virulence traits and evidence for clonality. J. Infect. Dis. 179:115-123.
81. Schubert, S., A. Rakin, H. Karch, et al. 1998. Prevalence of the "high-pathogenicity island" of Yersinia species among Escherichia coli strains that are pathogenic to humans. Infect. Immun. 66:480-485.
82. Scotland, S.M., G.A. Willshaw, H.R. Smith, et al. 1990. Properties of strains of Escherichia coli O26:H11 in relation to their enteropathogenic and enterohemorrhagic classification. J. Infect. Dis. 162:1069-1074.
83. Scotland, S.M., G.A. Willshaw, H.R. Smith, et al. 1993. Virulence properties of Escherichia coli strains belonging to serogroups O26, O55, O111 and O128 isolated in the United Kingdom in 1991 from patients with diarrhoea. Epidemiol. Infect. 111:429-438.
84. Shashkov, A.S., F.V. Toukach, N.A. Paramonov, et al. 1996. Structures of new acidic O-specific polysaccharides of the bacterium Proteus mirabilis serogroups O26 and O30. FEBS Lett. 20:247-251.
85. Smith, H.W., and M.B. Huggins. 1983. Effectiveness of phages in treating experimental Escherichia coli diarrhoea in calves, piglets and lambs. J. Gen. Microbiol. 129:2659-2675.
86. Smith, H.R., S.M. Scotland, G.A. Willshaw, et al. 1988. Vero cytotoxin production and presence of VT genes in Escherichia coli strains of animal origin. J. Gen. Microbiol. 134:829-834.
87. Smith, H.W., M.B. Huggins, and K.M. Shaw. 1987. The control of experimental Escherichia coli diarrhoea in calves by means of bacteriophages. J. Gen. Microbiol. 133:1111-1126.
88. Snyder, O.P. 1998. Escherichia coli and other pathogenic strains of E. coli [On-line]. Available: 〈www.hi-tm.com/Documents/Ecoli98.html〉. Accessed August 8, 2005.
89. Stevens, M.P., P.M. van Diemen, F. Dziva, et al. 2002. Options for the control of enterohaemorrhagic Escherichia coli in ruminants. Microbiology 148:3767-3778.
90. Thran, B.H., H.S. Hussein, M.R. Hall, et al. 2001. Occurrence of verotoxin-producing Escherichia coli in dairy heifers grazing an irrigated pasture. Toxicology 159:159-169.
91. Tkalcic, S., C.A. Brown, B.G. Harmon, et al. 2000. Effects of diet on rumen proliferation and fecal shedding of Escherichia coli O157:H7 in calves. J. Food Prot. 63:1630-1636.
92. Trabulsi, L.R., R. Keller, and T.A.T. Gomes. 2002. Typical and atypical enteropathogenic Escherichia coli. Emerg. Infect. Dis. 8:508-513.
93. Waddell, T.E., A. Mazzocco, J. Pacan, et al. 2002. Use of bacteriophages for control of Escherichia coli O157. U.S. patent 6485902.
94. Wells, J.G., L.D. Shipman, K.D. Greene, et al., 1991. Isolation of Escherichia coli serotype O157:H7 and other Shiga-like toxin-producing E. coli from dairy cattle. J. Clin. Microbiol. 29:985-989.
95. Wieler, L.H., E. Vieler, C. Erpenstein, et al. 1996. Shiga toxin-producing Escherichia coli strains from bovines: association of adhesion with carriage of eae and other genes. J. Clin. Microbiol. 34:2980-2984.
96. World Health Organization. 1999. New frontiers in the development of vaccines against enterotoxigenic (ETEC) and enterohermorrhagic E coli (EHEC) infections. Part II. Enterohemorrhagic E. coli (EHEC) vaccines. Weekly Epidemiol. Rec. 74:105-111.
97. Yamasaki, S. 2002. Development of vaccine for enterohemorrhagic Escherichia coli infection [in Japanese]. English abstract available online: 〈www.ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=Text&DB=pubmed〉. Accessed August 8, 2005.
98. Yoh, M., E.K. Frimpong, S.P. Voravuthikunchai, et al. 1999. Effect of subinhibitory concentrations of antimicrobial agents (quinolones and macrolide) on the production of verotoxin by enterohemorrhagic Escherichia coli O157:H7. Can. J. Microbiol. 45:732-739.
99. Zhang, W.L., M. Bielaszewska, A. Liesegang, et al. 2000a. Molecular characteristics and epidemiological significance of Shiga toxin-producing Escherichia coli O26 strains. J. Clin. Microbiol. 38:2134-2140.
100. Zhang, W.L., M. Bielaszewska, J. Bockelmuhl, et al. 2000b. Molecular analysis of H antigens reveals that human diarrheagenic Escherichia coli O26 strains that carry the eae gene belong to the H11 clonal complex. J. Clin. Microbiol. 38:2989-2993.
101. Zhao, S., D.G. White, B. Ge, et al. 2001. Identification and characterization of integron-mediated antibiotic resistance among Shiga toxin-producing Escherichia coli isolates. Appl. Environ. Microbiol. 67:1558-1564.