Changes in serotype caused by cell to cell contact between different Pseudomonas aeruginosa strains from cystic...

Area of Science:

• Microbiology
• Bacteriology
• Virology

Background:

• Pseudomonas aeruginosa is an opportunistic pathogen frequently found in cystic fibrosis patients.
• Strain variability in P. aeruginosa, including agglutination properties, can impact infection dynamics.
• Bacteriophage interactions are crucial in bacterial population control and evolution.

Purpose of the Study:

• To investigate the interaction between two P. aeruginosa strains with different agglutination properties (monoagglutinable and polyagglutinable) isolated from cystic fibrosis patients.
• To determine if co-culturing influences their serotype and phage type.
• To elucidate the conditions required for bacteriophage-mediated interactions between these strains.

Main Methods:

• Isolation and co-culturing of two P. aeruginosa strains from cystic fibrosis patients.
• Separation of strains based on azlocillin susceptibility.
• Serotyping and phage typing of bacterial colonies.
• Assessment of bacteriophage infection dynamics and plaque formation.

Main Results:

• Observed shifts in agglutination properties (monoagglutinable to polyagglutinable and vice versa) upon co-culturing.
• The monoagglutinable strain infected the polyagglutinable strain, but no infectious phages were released.
• Bacteriophage plaque formation on the receptor strain required the presence of the donor strain.

Conclusions:

• Co-culturing of P. aeruginosa strains can lead to changes in their phenotypic characteristics, such as agglutination.
• Bacteriophage infection dynamics are complex and can be influenced by the presence of other bacterial strains.
• The donor strain's presence is critical for successful phage propagation and plaque formation in this P. aeruginosa interaction model.