In vivo bioluminescence imaging of Escherichia coli O104:H4 and role of aerobactin during colonization of a mouse model of infection

Details

• Alternative Title:
  BMC Microbiol
• Personal Author:
  Torres, Alfredo G ; Cieza, Roberto J ; Rojas-Lopez, Maricarmen ; Blumentritt, Carla A ; Souza, Cristiane S ; Johnston, R Katie ; Strockbine, Nancy ; Kaper, James B ; Sbrana, Elena ; Popov, Vsevolod L
• Description:
  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 wild-type 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.
  
  
• Subjects:
  Animals Cecum Disease Models, Animal Escherichia Coli Escherichia Coli Infections Female Gene Deletion Hydroxamic Acids Iron Mice Mice, Inbred ICR Virulence Virulence Factors Whole Body Imaging

  More +
• Source:
  BMC Microbiol. 2012; 12:112.
• Document Type:
  Journal Article
• Volume:
  12
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:a1da38c55ba542aa89148690dfe83469c920144c03d2b423123b9a060bb013e8
• Download URL:
  https://stacks.cdc.gov/view/cdc/10901/cdc_10901_DS1.pdf
• File Type:
  [PDF - 1.43 MB ]