Proteomes of pathogenic Escherichia coli/Shigella group surveyed in their host environments

Abstract

Proteomic studies on Shigella dysenteriae, Shigella flexneri, enterohemorrhagic Escherichia coli and uropathogenic E. coli (UPEC) are reviewed. UPEC causes infections in the urogenital tract, whereas the other species colonize and, to varying degrees, invade the intestinal tract. Type III secretion systems used to breach the mucosal barrier by the intestinal pathogens revealed distinct expression patterns in different host environments. Dynamic adaptations to changes in nutrient availability and oxygen were observed, including increased reliance on anaerobic respiration and mixed acid fermentation in vivo. Utilization of carbon and nitrogen resources by the bacteria varied considerably depending on the host model investigated. Shigellae and UPEC adapted to metal ion sequestration in the mammalian host by enhancing expression of various receptors and transporters for iron and zinc. This appears to reflect the preferred intracellular life stage of Shigella spp. and responses of UPEC to high levels of lipocalin and lactotransferrin in the urinary tract.

Keywords::

• Escherichia coli proteome
• fitness adaptation
• host–pathogen interaction
• mass spectrometry
• Shigella proteome
• virulence

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Proteomic studies are advancing the knowledge of cellular and molecular host interactions with Escherichia coli/Shigella group pathogens.

• Proteomic studies comparing in vivo animal models and ex vivo cellular models of infection are at an early stage, but technological advancements in mass spectrometry promise to increase the knowledge of biological networks considerably in the next few years.

• Functional integration of proteins expressed by E. coli/Shigella group and contributing to virulence and fitness is increasing the knowledge as to why these pathogens compete in environments where mutualistic microbes also colonize the host. Proteomics is an integrated component of systems biology approaches to decipher the mechanisms of host–pathogen interactions. This knowledge will drive the research on the discovery of novel classes of bioactive molecules with the potential to replace antibiotics no longer effective due to antibiotic resistance development in E. coli/Shigella group pathogens.

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