Related Experiment Video
Updated: Jul 6, 2026
Time-Lapse Epifluorescence Microscopy Imaging of Pseudomonas aeruginosa and Staphylococcus aureus Heterogeneous Phenotypes
Published on: February 14, 2025
Comparative study of 7 fluorescent pseudomonad clinical isolates
A Chapalain1, G Rossignol, O Lesouhaitier
1Laboratoire de Microbiologie du Froid, UPRES 2123, Universite de Rouen, 55 rue Saint Germain, Evreux 27000, France.
Abstract:
There is some debate about the potential survival of Pseudomonas fluorescens at temperatures above 37 degrees C and its consequences for infectious potential, owing to the heterogeneity of clinical strains. Seven clinical strains growing at 37 degrees C or more were submitted for polyphasic identification; 2 were identified as Pseudomonas mosselii and 4 were precisely characterized as P. fluorescens bv. I or II. The binding indexes on glial cells of the strains identified as P. fluorescens bv. I and P. mosselii were compared with that of a reference psychrotrophic strain, P. fluorescens MF37 (bv. V). Clinical P. fluorescens had a similar adherence potential range than strain MF37. Conversely, the binding indexes for P. mosselii strains were 3 times greater than that for strain MF37. These data, and those obtained by comparing the cytotoxic activities of P. fluorescens clinical strains, suggest the existence of different virulence mechanisms, leading either to a low infectious form or to a microorganism with cytotoxic activity in the same range as that of P. mosselii or even Pseudomonas aeruginosa.
Insights
This study investigated Pseudomonas strains, finding that clinical Pseudomonas fluorescens showed varied adherence, while Pseudomonas mosselii exhibited significantly higher glial cell binding and potential virulence. This highlights diverse infectious mechanisms in these bacteria.
Area of Science:
- Microbiology
- Bacteriology
- Infectious Diseases
Background:
- Pseudomonas fluorescens survival and infectious potential at elevated temperatures are debated due to strain variability.
- Clinical isolates exhibiting growth above 37°C warrant investigation into their pathogenic mechanisms.
Purpose of the Study:
- To identify and characterize clinical Pseudomonas strains capable of growth at or above 37°C.
- To compare the glial cell binding and cytotoxic activities of these clinical strains with a reference strain.
Main Methods:
- Polyphasic identification of seven clinical bacterial strains.
- Assessment of glial cell binding indexes for identified strains.
- Comparison of cytotoxic activities among clinical Pseudomonas isolates.
Main Results:
- Two strains were identified as Pseudomonas mosselii, and four as Pseudomonas fluorescens bv. I or II.
- Clinical P. fluorescens strains displayed adherence similar to the reference strain P. fluorescens MF37.
- P. mosselii strains demonstrated threefold greater glial cell binding compared to the reference strain.
Conclusions:
- Clinical Pseudomonas strains exhibit diverse virulence mechanisms.
- P. mosselii possesses higher adherence and potential virulence compared to P. fluorescens bv. I/II.
- Findings suggest varying infectious potentials among clinical Pseudomonas isolates, including cytotoxic activity comparable to Pseudomonas aeruginosa.
