Uropathogenic Escherichia coli proliferate as a coccoid morphotype inside human host cells

Area of Science:

• Microbiology
• Cell Biology
• Bacterial Pathogenesis

Background:

• Escherichia coli is a well-established bacterial model organism.
• E. coli typically exhibits a rod shape but can alter morphology under stress.
• Uropathogenic E. coli (UPEC) is a significant human pathogen.

Purpose of the Study:

• To elucidate the molecular mechanisms of UPEC morphological transition to coccoid forms within host cells.
• To investigate the dynamics of cell division and protein localization during intracellular UPEC proliferation.
• To understand the role of division rate in UPEC adaptability.

Main Methods:

• Utilized an in vitro infection model of human host cells.
• Employed advanced dynamical imaging techniques to visualize intracellular UPEC.
• Analyzed subcellular protein dynamics, focusing on division proteins like FtsZ.

Main Results:

• Observed UPEC dividing and proliferating as coccoid-shaped cells within host cells.
• Found that cell division frequency exceeded cell growth rate, leading to the rod-to-coccoid transition.
• Demonstrated that division proteins localize and constrict similarly to vegetative growth, but FtsZ constriction precedes nucleoid segregation.

Conclusions:

• Intracellular UPEC undergoes a significant morphological shift to coccoid shapes.
• The rate of cell division is modulated to facilitate adaptation within the host.
• This division rate modulation is a key factor in the single-cell adaptability of intracellular UPEC.