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Updated: Feb 4, 2026
Development of a Polymicrobial Colony Biofilm Model to Test Antimicrobials in Cystic Fibrosis
Published on: September 20, 2024
Activity of a novel antimicrobial peptide against Pseudomonas aeruginosa biofilms
Trevor Beaudoin1, Tracy A Stone2,3, Miroslawa Glibowicka2
1Division of Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, Canada.
Abstract:
With the increasing recognition of biofilms in human disease, the development of novel antimicrobial therapies is of critical importance. For example, in patients with cystic fibrosis (CF), the acquisition of host-adapted, chronic Pseudomonas aeruginosa infection is associated with a decline in lung function and increased mortality. Our objective was to test the in vitro efficacy of a membrane-active antimicrobial peptide we designed, termed 6K-F17 (sequence: KKKKKK-AAFAAWAAFAA-NH2), against multidrug resistant P. aeruginosa biofilms. This peptide displays high antimicrobial activity against a range of pathogenic bacteria, yet is non-hemolytic to human erythrocytes and non-toxic to human bronchial epithelial cells. In the present work, P. aeruginosa strain PAO1, and four multidrug resistant (MDR) isolates from chronically infected CF individuals, were grown as 48-hour biofilms in a static biofilm slide chamber model. These biofilms were then exposed to varying concentrations of 6K-F17 alone, or in the presence of tobramycin, prior to confocal imaging. Biofilm biovolume and viability were assessed. 6K-F17 was able to kill biofilms - even in the presence of sputum - and greatly reduce biofilm biovolume in PAO1 and MDR isolates. Strikingly, when used in conjunction with tobramycin, low doses of 6K-F17 significantly potentiated tobramycin killing, leading to biofilm destruction.
Insights
A novel peptide, 6K-F17, effectively eradicates Pseudomonas aeruginosa biofilms, even in cystic fibrosis (CF) sputum. Combined with tobramycin, it dramatically enhances antibiotic efficacy against these resistant bacterial communities.
Area of Science:
- Microbiology
- Biochemistry
- Pharmacology
Background:
- Biofilms are increasingly implicated in human diseases, necessitating new antimicrobial strategies.
- Chronic Pseudomonas aeruginosa infections in cystic fibrosis (CF) patients significantly worsen lung function and survival rates.
Purpose of the Study:
- To evaluate the in vitro effectiveness of a designed membrane-active antimicrobial peptide, 6K-F17, against multidrug-resistant (MDR) P. aeruginosa biofilms.
- To assess the synergistic potential of 6K-F17 when combined with tobramycin for biofilm eradication.
Main Methods:
- P. aeruginosa strains, including MDR isolates from CF patients, were cultured as 48-hour biofilms.
- Biofilms were treated with varying concentrations of 6K-F17, alone or with tobramycin, in a static biofilm slide chamber model.
- Confocal imaging was used to assess biofilm biovolume and viability.
Main Results:
- 6K-F17 demonstrated significant efficacy in reducing biofilm biovolume and killing bacteria in both standard and MDR P. aeruginosa isolates, even within sputum.
- The combination of low-dose 6K-F17 and tobramycin resulted in substantial potentiation of killing and complete biofilm destruction.
Conclusions:
- The designed peptide 6K-F17 shows potent antimicrobial activity against P. aeruginosa biofilms.
- 6K-F17 holds promise as a therapeutic agent, particularly in combination with existing antibiotics, for treating chronic P. aeruginosa infections in CF patients.
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