In vivo bioluminescence imaging of Escherichia coli O104

H4 and role of aerobactin during colonization of a mouse model of infection

Alfredo Torres, Roberto J. Cieza, Maricarmen Rojas-Lopez, Carla A. Blumentritt, Cristiane S. Souza, R. Katie Johnston, Nancy Strockbine, James B. Kaper, Elena Sbrana, Vsevolod Popov

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Background: A major outbreak of bloody diarrhea associated with Shiga toxin-producing Escherichia coli O104:H4 occurred early in 2011, to which an unusual number of hemolytic uremic syndrome cases were linked. Due to limited information regarding pathogenesis and/or virulence properties of this particular serotype, we investigated the contribution of the aerobactin iron transport system during in vitro and in vivo conditions. Results: A bioluminescent reporter construct was used to perform real-time monitoring of E. coli O104:H4 in a mouse model of infection. We verified that our reporter strain maintained characteristics and growth kinetics that were similar to those of the wild-type E. coli strain. We found that the intestinal cecum of ICR (CD-1) mice was colonized by O104:H4, with bacteria persisting for up to 7 days after intragastric inoculation. MALDI-TOF analysis of heat-extracted proteins was performed to identify putative surface-exposed virulence determinants. A protein with a high similarity to the aerobactin iron receptor was identified and further demonstrated to be up-regulated in E. coli O104:H4 when grown on MacConkey agar or during iron-depleted conditions. Because the aerobactin iron acquisition system is a key virulence factor in Enterobacteriaceae, an isogenic aerobactin receptor (iutA) mutant was created and its intestinal fitness assessed in the murine model. We demonstrated that the aerobactin mutant was out-competed by the wildtype E. coli O104:H4 during in vivo competition experiments, and the mutant was unable to persist in the cecum. Conclusion: Our findings demonstrate that bioluminescent imaging is a useful tool to monitor E. coli O104:H4 colonization properties, and the murine model can become a rapid way to evaluate bacterial factors associated with fitness and/or colonization during E. coli O104:H4 infections.

Original languageEnglish (US)
Article number112
JournalBMC Microbiology
Volume12
DOIs
StatePublished - 2012

Fingerprint

Iron
Infection
Cecum
Virulence
Shiga-Toxigenic Escherichia coli
Hemolytic-Uremic Syndrome
Matrix-Assisted Laser Desorption-Ionization Mass Spectrometry
Virulence Factors
Enterobacteriaceae
Agar
Disease Outbreaks
Escherichia coli O104
aerobactin
Diarrhea
Proteins
Hot Temperature
Escherichia coli
Bacteria
Growth
aerobactin receptor

ASJC Scopus subject areas

  • Microbiology (medical)
  • Microbiology

Cite this

In vivo bioluminescence imaging of Escherichia coli O104 : H4 and role of aerobactin during colonization of a mouse model of infection. / Torres, Alfredo; Cieza, Roberto J.; Rojas-Lopez, Maricarmen; Blumentritt, Carla A.; Souza, Cristiane S.; Johnston, R. Katie; Strockbine, Nancy; Kaper, James B.; Sbrana, Elena; Popov, Vsevolod.

In: BMC Microbiology, Vol. 12, 112, 2012.

Research output: Contribution to journalArticle

Torres, Alfredo ; Cieza, Roberto J. ; Rojas-Lopez, Maricarmen ; Blumentritt, Carla A. ; Souza, Cristiane S. ; Johnston, R. Katie ; Strockbine, Nancy ; Kaper, James B. ; Sbrana, Elena ; Popov, Vsevolod. / In vivo bioluminescence imaging of Escherichia coli O104 : H4 and role of aerobactin during colonization of a mouse model of infection. In: BMC Microbiology. 2012 ; Vol. 12.
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abstract = "Background: A major outbreak of bloody diarrhea associated with Shiga toxin-producing Escherichia coli O104:H4 occurred early in 2011, to which an unusual number of hemolytic uremic syndrome cases were linked. Due to limited information regarding pathogenesis and/or virulence properties of this particular serotype, we investigated the contribution of the aerobactin iron transport system during in vitro and in vivo conditions. Results: A bioluminescent reporter construct was used to perform real-time monitoring of E. coli O104:H4 in a mouse model of infection. We verified that our reporter strain maintained characteristics and growth kinetics that were similar to those of the wild-type E. coli strain. We found that the intestinal cecum of ICR (CD-1) mice was colonized by O104:H4, with bacteria persisting for up to 7 days after intragastric inoculation. MALDI-TOF analysis of heat-extracted proteins was performed to identify putative surface-exposed virulence determinants. A protein with a high similarity to the aerobactin iron receptor was identified and further demonstrated to be up-regulated in E. coli O104:H4 when grown on MacConkey agar or during iron-depleted conditions. Because the aerobactin iron acquisition system is a key virulence factor in Enterobacteriaceae, an isogenic aerobactin receptor (iutA) mutant was created and its intestinal fitness assessed in the murine model. We demonstrated that the aerobactin mutant was out-competed by the wildtype E. coli O104:H4 during in vivo competition experiments, and the mutant was unable to persist in the cecum. Conclusion: Our findings demonstrate that bioluminescent imaging is a useful tool to monitor E. coli O104:H4 colonization properties, and the murine model can become a rapid way to evaluate bacterial factors associated with fitness and/or colonization during E. coli O104:H4 infections.",
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T2 - H4 and role of aerobactin during colonization of a mouse model of infection

AU - Torres, Alfredo

AU - Cieza, Roberto J.

AU - Rojas-Lopez, Maricarmen

AU - Blumentritt, Carla A.

AU - Souza, Cristiane S.

AU - Johnston, R. Katie

AU - Strockbine, Nancy

AU - Kaper, James B.

AU - Sbrana, Elena

AU - Popov, Vsevolod

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