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Updated: Jun 3, 2025
Author Spotlight: Understanding Rhamnolipid Regulation in Pseudomonas aeruginosa
Published on: March 29, 2024
Comparative phenotypic and proteomic analysis of colistin-exposed Pseudomonas aeruginosa
Nguyen Bao Vy Tran1, Thuc Quyen Huynh2, Hong Loan Ngo1
1School of Biotechnology, International University, Vietnam National University, Ho Chi Minh City 700000, Vietnam.
Introduction:
The emergence of colistin resistance threatens the treatment of Pseudomonas aeruginosa infections.
Methods:
In this study, in vitro development of colistin resistance was investigated using comparative phenotypic and proteomic analysis of P. aeruginosa ATCC 9027, its 14-day colistin sub-MIC exposed strain (Col-E1), and 10-day antibiotic-free cultured Col-E1 strain (Col-E2). Antibiotic susceptibility, morphology, virulence factors, and proteomic changes were assessed using disc-diffusion, agar-based, spectrophotometry, SEM, and iTRAQ-LC-MS/MS methods.
Results:
Colistin-exposed strains decreased susceptibility to colistin while remaining susceptible to other antibiotics. Col-E1 reduced the cell lengths by 17.67% and the colony size by 36.16% compared to the initial strain. The reduction remained in Col-E2. The pyocyanin production was reduced in Col-E1 (p=0.025, Tukey HSD) and increased again in Col-E2 (p=0.005, Tukey HSD). In contrast, no significant changes in elastase, protease, rhamnolipid, pyoverdine, and biofilm production were observed (p>0.05, Tukey HSD). In Col-E1, the proteome analysis showed 135 differentially expressed proteins (DEPs) of which 94 DEPs (69.23%) maintained their expression change in Col-E2. Among DEPs, 82 were involved in metabolism and protein synthesis. Some DEPs (6/135) played a role in stress response such as GrpE (fold change: 14.93) and Hmp (fold change: 12.08). In particular, membrane proteins like OprD, DdlB, and OprI showed significant colistin response with fold change of -8.47, 6.43 and 6.19, respectively.
Conclusions:
In summary, colistin response in P. aeruginosa seemed to affect morphology, production of pyocyanin, and proteins of metabolism, protein synthesis, stress response and membrane.
Insights
Colistin resistance in Pseudomonas aeruginosa alters cell morphology and pyocyanin production. Proteomic analysis reveals changes in metabolism, protein synthesis, stress response, and membrane proteins.
Area of Science:
- Microbiology
- Proteomics
- Antimicrobial Resistance
Background:
- Colistin is a critical antibiotic for treating multidrug-resistant Gram-negative bacterial infections.
- The emergence of colistin resistance in *Pseudomonas aeruginosa* poses a significant threat to clinical treatment outcomes.
Purpose of the Study:
- To investigate the in vitro development of colistin resistance in *Pseudomonas aeruginosa*.
- To analyze phenotypic and proteomic changes associated with colistin exposure and subsequent recovery.
Main Methods:
- Comparative phenotypic and proteomic analysis of *P. aeruginosa* ATCC 9027 and its colistin-exposed strains (Col-E1, Col-E2).
- Methods included disc-diffusion, agar-based assays, spectrophotometry, scanning electron microscopy (SEM), and iTRAQ-LC-MS/MS.
Main Results:
- Colistin-exposed strains showed reduced susceptibility to colistin but remained susceptible to other antibiotics.
- Significant alterations in cell morphology, colony size, and pyocyanin production were observed.
- Proteomic analysis identified 135 differentially expressed proteins (DEPs), with 82 involved in metabolism and protein synthesis. Key membrane proteins like OprD, DdlB, and OprI showed significant changes.
Conclusions:
- Colistin resistance in *P. aeruginosa* impacts bacterial morphology, pyocyanin production, and the expression of proteins involved in metabolism, protein synthesis, stress response, and membrane function.
- Understanding these molecular changes is crucial for developing strategies to combat colistin resistance.
