Phage ΦPan70, a Putative Temperate Phage, Controls Pseudomonas aeruginosa in Planktonic, Biofilm and Burn Mouse Model Assays
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Angela V Holguín1, Guillermo Rangel2, Viviana Clavijo3
1Department of Biological Sciences, Universidad de los Andes, Carrera 1#18A-12, Bogotá 111711, Colombia. av.holguin103@uniandes.edu.co.
Abstract:
Pseudomonas aeruginosa is one of the Multi-Drug-Resistant organisms most frequently isolated worldwide and, because of a shortage of new antibiotics, bacteriophages are considered an alternative for its treatment. Previously, P. aeruginosa phages were isolated and best candidates were chosen based on their ability to form clear plaques and their host range. This work aimed to characterize one of those phages, ΦPan70, preliminarily identified as a good candidate for phage-therapy. We performed infection curves, biofilm removal assays, transmission-electron-microscopy, pulsed-field-gel-electrophoresis, and studied the in vivo ΦPan70 biological activity in the burned mouse model. ΦPan70 was classified as a member of the Myoviridae family and, in both planktonic cells and biofilms, was responsible for a significant reduction in the bacterial population. The burned mouse model showed an animal survival between 80% and 100%, significantly different from the control animals (0%). However, analysis of the ΦPan70 genome revealed that it was 64% identical to F10, a temperate P. aeruginosa phage. Gene annotation indicated ΦPan70 as a new, but possible temperate phage, therefore not ideal for phage-therapy. Based on this, we recommend genome sequence analysis as an early step to select candidate phages for potential application in phage-therapy, before entering into a more intensive characterization.
Insights
Bacteriophages show promise for treating multi-drug-resistant Pseudomonas aeruginosa infections. However, phage ΦPan70, despite reducing bacterial populations and improving survival in mice, was found to be a potentially temperate phage, unsuitable for therapy.
Area of Science:
- Microbiology
- Molecular Biology
- Infectious Diseases
Background:
- Pseudomonas aeruginosa is a major multi-drug-resistant pathogen.
- Bacteriophages are explored as an alternative to antibiotics due to a lack of new drugs.
- Phage selection traditionally involves plaque formation and host range assessment.
Purpose of the Study:
- To characterize bacteriophage ΦPan70 as a potential candidate for phage therapy against Pseudomonas aeruginosa.
- To evaluate ΦPan70's efficacy in vitro and in vivo.
Main Methods:
- Infection curves and biofilm removal assays were conducted.
- Transmission electron microscopy and pulsed-field gel electrophoresis were used for structural and genomic analysis.
- In vivo efficacy was tested in a burned mouse model.
Main Results:
- ΦPan70, a Myoviridae family member, significantly reduced planktonic and biofilm bacterial populations.
- The phage demonstrated high efficacy in the burned mouse model, with 80-100% survival.
- Genomic analysis revealed 64% identity to a temperate phage, suggesting ΦPan70 may also be temperate.
Conclusions:
- While effective in reducing bacterial load and improving survival, ΦPan70's potential temperate nature makes it unsuitable for phage therapy.
- Genome sequencing should be an early step in selecting candidate phages for therapeutic applications.
