[Surviving Forms in Antibiotic-Treated Pseudomonas aeruginosa]

Area of Science:

• Microbiology
• Bacterial Physiology
• Antimicrobial Resistance

Background:

• Persister cells ensure bacterial survival against antibiotics but are not inheritable.
• Antibiotic tolerance in persisters is reversible, distinguishing them from resistant cells.

Purpose of the Study:

• To investigate the transformation of Pseudomonas aeruginosa persister cells into dormant forms after ciprofloxacin treatment.
• To characterize the heterogeneity and survival strategies of these dormant subpopulations.

Main Methods:

• Treatment of Pseudomonas aeruginosa with ciprofloxacin (25-100 μg/mL).
• Incubation of persister subpopulations (Type 1 and Type 2) under specific conditions.
• Analysis of cell morphology, colony-forming capacity, and heat resistance (70°C).
• Live/Dead viability testing to assess cell integrity.

Main Results:

• Persisters transformed into dormant cystlike cells (CLC) and non-culturable (NC) cells.
• Heterogeneity observed in germination, heat resistance, and morphology of Type 1 and Type 2 persisters.
• Most 1-month persisters, especially Type 2, lost colony-forming capacity, indicating a transition to an uncultured state.
• A minor subpopulation of ciprofloxacin-tolerant and resistant cells survived and grew.

Conclusions:

• Pseudomonas aeruginosa persisters can mature into dormant forms (CLC, NC, L-forms), contributing to persistent infections.
• Dormant forms and antibiotic-resistant cells are crucial for understanding latent infections and developing novel antimicrobial strategies.