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The Anti-Bacterial Iron-Restriction Defence Mechanism of Egg White: The Potential Role of Lipocalin-Like Proteins in Resistance against Salmonella

Abstract : Salmonella enterica causes 93.8 million human cases of gastroenteritis and bacteremia worldwide which subsequently results into 155,000 deaths annually. Salmonella Enteritidis serovar (SE) is the most frequently detected Salmonella enterica in foodborne outbreaks in the European Union. Among such outbreaks, egg and egg products are identified as the most common vehicles of infection. One of the main antibacterial properties of egg white is iron restriction which results from the presence of an ironbinding protein (ovotransferrin). To circumvent iron restriction, SE synthesises siderophores (i.e. enterobactin [Ent] and salmochelin) that can chelate iron from host iron-binding proteins to make it available to the bacterium. The aim of this project is to explore the role that lipocalin-type proteins might play a role in sequestering bacterial siderophores synthesized in egg white.The three lipocalin-type proteins found in egg white were over-expressed, purified and tested for their ability to bind Fe(III)-Ent complexes. Mutants knocked-out for enterobactin synthesis as well as for salmochelin synthesis/export and import were then used to determine whether exposure to lipocalin-type proteins limits SE growth and whether salmochelin secretion overcomes any observed inhibition by lipocalins.It was shown that the Ex-FABP protein, identified as an egg white lipocalin, is able to inhibit bacterial growth under ironlimited conditions. However, Cal-γ and α-1-ovoglycoprotein do not seem to have a role in siderophore sequestration. Overall, this project provides new insight on egg white anti-bacterial mechanisms that would be of high relevance to the sector of egg production and processing.
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https://hal.inrae.fr/hal-02790284
Contributor : Migration Prodinra <>
Submitted on : Friday, June 5, 2020 - 6:13:36 AM
Last modification on : Thursday, March 18, 2021 - 11:44:09 AM

Identifiers

  • HAL Id : hal-02790284, version 1
  • PRODINRA : 493768

Citation

Louis Julien, Kimon-Andreas Karatzas, Florence Baron, Marie-Françoise Cochet, Sylvie Bonnassie-Rouxin, et al.. The Anti-Bacterial Iron-Restriction Defence Mechanism of Egg White: The Potential Role of Lipocalin-Like Proteins in Resistance against Salmonella. ASM congress (American Society for Microbiology), Jun 2019, San Francisco, United States. 2019. ⟨hal-02790284⟩

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