Polyphosphate kinase 1 is a pathogenesis determinant in Campylobacter jejuni

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Molecular Biology

Background:

• Campylobacter jejuni is a major cause of bacterial gastroenteritis.
• Its pathogenesis mechanisms are not fully understood compared to other enteric bacteria.
• The stringent response and polyphosphate (poly-P) are linked to virulence in other bacteria.

Purpose of the Study:

• To investigate the role of poly-P in C. jejuni stress survival and pathogenesis.
• To characterize the function of polyphosphate kinase 1 (ppk1) in C. jejuni.

Main Methods:

• Generated a ppk1 deletion mutant (Deltappk1) in C. jejuni strain 81-176.
• Assessed poly-P levels in wild-type and mutant strains.
• Performed phenotypic analyses including stress survival, motility, oxidative stress, biofilm formation, intraepithelial cell survival, and chick colonization.

Main Results:

• The Deltappk1 mutant had low poly-P levels and was defective in osmotic shock and low-nutrient stress survival.
• Motility and oxidative stress were unaffected, but biofilm formation increased in the Deltappk1 mutant.
• The Deltappk1 mutant showed reduced intraepithelial cell survival and a significant chick colonization defect.

Conclusions:

• Poly-P accumulation and utilization are vital for C. jejuni pathogenesis.
• Poly-P contributes to C. jejuni's adaptation to specific stresses.
• Poly-P metabolism is linked to stringent response mechanisms in C. jejuni, with both conserved and unique roles compared to other bacteria.