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Sackler School of Graduate Biomedical Sciences

Leong Lab Sheds New Light on E coli Pathogenesis

Friday, January 11, 2019
Food-borne pathogen does not require virus replication for disease.
E coli
Image: Janice Haney Carr, CDC

In an article published in PLoS Pathogen this week, John Leong's group have revealed new insights into the way enterohemorrhagic E coli  causes disease. Their article was highlighted in a press release from the journal and also featured here.

The authors summarize their findings in this way.

"Enterohemorrhagic Escherichia coli (EHEC), a food-borne pathogen that produces Shiga toxin, is associated with serious disease outbreaks worldwide, including over 390 food poisoning outbreaks in the U.S. in the last two decades. Humans acquire EHEC by ingesting contaminated food or water, or through contact with animals or their environment. Infection and toxin production may result in localized hemorrhagic colitis, but may progress to life-threatening systemic hemolytic uremic syndrome (HUS), the leading cause of kidney failure in children. Treatment for EHEC or HUS remains elusive, as antibiotics have been shown to exacerbate disease. Shiga toxin genes reside on a dormant bacterial virus present in the EHEC genome, but are expressed when the virus is induced to leave its dormant state and begin to replicate. Extensive virus replication has been thought necessary to produce sufficient toxin to cause disease. Using viral and bacterial mutants in our EHEC disease mouse model, we showed that whereas an inducing signal needed to begin viral replication was essential for lethal disease, virus production was not: sufficient Shiga toxin was produced to cause lethal mouse disease, even without viral replication. Future analyses of EHEC-infected human samples will determine whether this same phenomenon applies, potentially directing intervention strategies."

Balasubramanian S, Osburne MS, BrinJones H, Tai AK, Leong JM. 2019. Prophage induction, but not production of phage particles, is required for lethal disease in a microbiome-replete murine model of enterohemorrhagic E. coli infection. PLoS Pathog. 15: e1007494.

Read the article.