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Published on: May 4, 2018
Evaluation of Antimicrobial Activity of Novel Chimeric M-PEX12 Peptide Against Acinetobacter baumannii
Yasin Rakhshani1, Hamideh Mahmoodzadeh Hosseini2, Seyed Ali Mirhosseini2
1Department of Biology, SR.C., Islamic Azad University, Tehran, Iran.
Background:
Acinetobacter baumannii-induced nosocomial pneumonia and its associated biofilm infections pose significant clinical challenges due to high rates of antibiotic resistance. Traditional antibiotic treatments encounter numerous obstacles, making antimicrobial peptides (AMPs) a promising alternative for controlling such pathogens. The emergence of multidrug-resistant strains necessitates the exploration of innovative therapeutic strategies.
Objectives:
We recently designed a novel hybrid peptide, M-PEX12, which exhibits antimicrobial activity and low toxicity in vitro. To confirm its therapeutic potential, we evaluated it in both in vitro and in vivo settings.
Methods:
M-PEX12 was evaluated using time-kill kinetics, thermal stability, reactive oxygen species (ROS) generation, biofilm inhibition assays, scanning electron microscopy (SEM), cytotoxicity tests, and virulence gene expression analysis. Its in vivo activity against A. baumannii was also assessed in an animal model.
Results:
The time-kill kinetics assay indicated that exposure to M-PEX12 at 1x minimum inhibitory concentration (MIC) (33/154) and 2x MIC resulted in over 95% reduction in bacterial populations within 30 minutes. Notably, the bacteria did not develop resistance to increased temperatures. M-PEX12 effectively disrupted biofilm formation at various concentrations. Field emission SEM revealed significant ultrastructural deformities in A. baumannii cell walls. Treatment with M-PEX12 increased production of intracellular ROS and decreased cell viability in a concentration-dependent manner. Cytotoxicity assays showed no significant effect on HEK293 cell viability. Additionally, expression levels of omp33, csuE, bfmR, and ompA were significantly reduced. The antimicrobial efficacy of M-PEX12 was confirmed in vivo.
Conclusions:
M-PEX12 exhibited significant antimicrobial activity and low toxicity in a mouse model, suggesting its potential as a treatment for drug-resistant bacterial infections.
Insights
A novel peptide, M-PEX12, effectively combats antibiotic-resistant Acinetobacter baumannii pneumonia by rapidly killing bacteria and disrupting biofilms. This peptide shows low toxicity and significant therapeutic potential in vivo.
Area of Science:
- Microbiology
- Biochemistry
- Drug Discovery
Background:
- Acinetobacter baumannii causes challenging nosocomial pneumonia and biofilm infections.
- High antibiotic resistance rates necessitate novel therapeutic strategies like antimicrobial peptides (AMPs).
Purpose of the Study:
- To evaluate the therapeutic potential of a novel hybrid peptide, M-PEX12, against Acinetobacter baumannii.
- To assess M-PEX12's efficacy and safety in vitro and in vivo.
Main Methods:
- Time-kill kinetics, thermal stability, ROS generation, and biofilm inhibition assays were performed.
- Scanning electron microscopy (SEM), cytotoxicity tests, and virulence gene expression analysis were conducted.
- In vivo efficacy was assessed in a mouse model.
Main Results:
- M-PEX12 rapidly reduced bacterial populations (>95% in 30 min) and disrupted biofilm formation.
- SEM revealed significant bacterial cell wall damage, and M-PEX12 increased intracellular ROS.
- No significant cytotoxicity was observed in HEK293 cells, and virulence gene expression was reduced.
Conclusions:
- M-PEX12 demonstrates potent antimicrobial activity and low toxicity against Acinetobacter baumannii.
- The peptide's efficacy in vivo suggests its potential as a treatment for drug-resistant bacterial infections.
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