Andrew J Fabich

We previously isolated a spontaneous mutant of Escherichia coli K-12, strain MG1655, following passage through the streptomycin-treated mouse intestine, that has colonization traits superior to the wild-type parent strain (M. P. Leatham et al., Infect. Immun. 73:8039–8049, 2005). This intestine-adapted strain (E. coli MG1655*) grew faster on several different carbon sources than the wild type and was nonmotile due to deletion of the flhD gene. We now report the results of several high-throughput genomic analysis approaches to further characterize E. coli MG1655*. Whole-genome pyrosequencing did not reveal any changes on its genome, aside from the deletion at the flhDC locus, that could explain the colonization advantage of E. coli MG1655*. Microarray analysis revealed modest yet significant induction of catabolic gene systems across the genome in both E. coli MG1655* and an isogenic flhD mutant constructed in the laboratory. Catabolome analysis with Biolog GN2 microplates revealed a...

Mammals are aerobes that harbor an intestinal ecosystem dominated by large numbers of anaerobic microorganisms. However, the role of oxygen in the intestinal ecosystem is largely unexplored. We used systematic mutational analysis to determine the role of respiratory metabolism in the streptomycin-treated mouse model of intestinal colonization. Here we provide evidence that aerobic respiration is required for commensal and pathogenic Escherichia coli to colonize mice. Our results showed that mutants lacking ATP synthase, which is required for all respiratory energy-conserving metabolism, were eliminated by competition with respiratory-competent wild-type strains. Mutants lacking the high-affinity cytochrome bd oxidase, which is used when oxygen tensions are low, also failed to colonize. However, the low-affinity cytochrome bo3 oxidase, which is used when oxygen tension is high, was found not to be necessary for colonization. Mutants lacking either nitrate reductase or fumarate reduct...

Enterohemorrhagic Escherechia coli is a serious human pathogen causing bloody diarrhea and hemolytic uremic syndrome. It is difficult to study in animal models, but pathogenesis may be modeled in mice with the similar murine pathogen, Citrobacter rodentium. C. rodentium does not cause disease in streptomycin-treated mice, suggesting that it is competition with other facultative anaerobes that triggers pathogenesis. Streptomycin-treated mice were co-colonized with C. rodentium and a commensal E. coli strain. The intestinal microbiota of each group was observed over a 15-day period using quantitative PCR. Colon weights were also measured over the same period. Results indicate that the disease caused by competition is not similar to normal C. rodentium pathogenesis. Further research is necessary to determine the precise mechanism of pathogenesis in this experimental model. The outcome may provide new insight into enterohemorrhagic E. coli prevention and treatment. COLONIZATION OF INTES...

ISSN: 1937-9056 Copyright © 2018 Answers in Genesis, Inc. All content is owned by Answers in Genesis (“AiG”) unless otherwise indicated. AiG consents to unlimited copying and distribution of print copies of Answers Research Journal articles for non-commercial, non-sale purposes only, provided the following conditions are met: the author of the article is clearly identified; Answers in Genesis is acknowledged as the copyright owner; Answers Research Journal and its website, www.answersresearchjournal.org, are acknowledged as the publication source; and the integrity of the work is not compromised in any way. For website and other electronic distribution and publication, AiG consents to republication of article abstracts with direct links to the full papers on the ARJ website. All rights reserved. For more information write to: Answers in Genesis, PO Box 510, Hebron, KY 41048, Attn: Editor, Answers Research Journal. The views expressed are those of the writer(s) and not necessarily th...

Citrobacter rodentium is a Gram-negative bacterium which causes transmissible murine colonic hyperplasia and models the virulence of enterohemorrhagic Escherichia coli in vivo. Thus, C. rodentium is used to study human gastrointestinal disease. We present the draft genome sequence of C. rodentium strain ATCC 51459, also known as DBS100.