Altered regulation of septal peptidoglycan synthesis modulates β-lactam susceptibility in Pseudomonas aeruginosa.

Mutations in the FtsI pedestal domain of Pseudomonas aeruginosa alter septal peptidoglycan regulation and modulate β-lactam susceptibility, with some increasing hypersusceptibility.

• Why it matters: Understanding how divisome regulation affects antibiotic susceptibility is crucial for developing strategies against resistant bacterial strains, especially in clinical P. aeruginosa isolates.
• What they did: The study identified substitutions in the non-enzymatic pedestal domain of FtsI that bypass FtsN requirement, mapped these mutations onto the FtsQLBWI structure, and assessed their impact on β-lactam resistance.
• The result: Variants at the FtsI-FtsL interface modestly reduce β-lactam susceptibility, while a mutation on the opposite face causes striking FtsN-dependent hypersusceptibility, revealing the pedestal domain as a key regulatory hub influencing antibiotic response.