Details:

Alternative Title:
BMC Microbiol
Personal Author:
Torres, Alfredo G; Cieza, Roberto J; Rojas-Lopez, Maricarmen; Blumentritt, Carla A; Souza, Cristiane S; ... More +
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; Less -
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.
Subject:
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Animals
Cecum
Disease Models, Animal
Escherichia Coli
Escherichia Coli Infections
Female
Gene Deletion
Hydroxamic Acids
Iron
Mice
Mice, Inbred ICR
Research Article
Virulence
Virulence Factors
Whole Body Imaging

Source:
BMC Microbiol. 2012; 12:112.;
Document Type:
Journal Article;
Collection(s):
CDC Public Access
Main Document Checksum:
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urn:sha256:a1da38c55ba542aa89148690dfe83469c920144c03d2b423123b9a060bb013e8
File Type:

Supporting Files

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