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The type III secretion system is involved in Escherichia coli K1 interactions with Acanthamoeba

Ruqaiyyah Siddiqui1, Huma Malik, Mehwish Sagheer

  • 1Aga Khan University, Stadium Road, Karachi, Pakistan.

Experimental Parasitology
|May 28, 2011
PubMed

Insights

The type III secretion system is crucial for E. coli K1 survival and invasion in Acanthamoeba castellanii. Deleting this system significantly impairs bacterial interaction with the amoeba, impacting pathogenicity.

Area of Science:

  • Microbiology
  • Pathogenesis
  • Host-Pathogen Interactions

Background:

  • Gram-negative bacteria utilize type III secretion systems (T3SS) to deliver effectors into host cells, influencing host processes.
  • T3SS are well-established virulence factors in pathogens like Yersinia, Pseudomonas, and EHEC.
  • Neuropathogenic E. coli K1 strains possess a T3SS, suggesting its potential role in virulence.

Purpose of the Study:

  • To investigate the role of the type III secretion system in the interaction of E. coli K1 with Acanthamoeba castellanii.
  • To determine if T3SS is essential for E. coli K1 invasion and intracellular survival within Acanthamoeba.
  • To assess the impact of T3SS on E. coli K1 survival during Acanthamoeba encystment.

Main Methods:

  • Construction of a type III secretion system deletion mutant in E. coli strain EC10.
  • Invasion and intracellular survival assays using Acanthamoeba castellanii as a host model.
  • Encystment assays to evaluate bacterial survival within Acanthamoeba cysts.

Main Results:

  • The T3SS deletion mutant of E. coli EC10 showed impaired invasion and intracellular survival in Acanthamoeba castellanii compared to the parent strain.
  • Significantly reduced survival of the T3SS deletion mutant within Acanthamoeba cysts was observed (P<0.01).

Conclusions:

  • This study provides the first evidence that the type III secretion system is critical for E. coli K1 interactions with Acanthamoeba.
  • Understanding amoebae-bacterial pathogen interactions is vital for developing strategies against E. coli transmission.

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