pIN32: a cointegrate plasmid with IncHI2 and IncFII components

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Enterobacter cloacae is an opportunistic pathogen.
• Plasmids play a crucial role in bacterial adaptation and virulence.
• Understanding plasmid biology is essential for combating antimicrobial resistance.

Purpose of the Study:

• To characterize the transferable plasmid pIN32 isolated from Enterobacter cloacae.
• To investigate the phenotypic changes and genetic alterations of plasmid derivatives.

Main Methods:

• Plasmid isolation and characterization.
• Bacterial conjugation experiments.
• Plasmid DNA analysis and sequencing.

Main Results:

• The 216 MDa plasmid pIN32 exhibited IncHI2 phenotype with temperature-sensitive transfer.
• A derivative, pIN32-1 (60 MDa), lost IncHI2 phenotype, gained IncFII characteristics, and showed constitutive pilus expression.
• Another derivative, pIN32-2 (184.3 MDa), retained IncHI2 phenotype after growth at 37°C.

Conclusions:

• Plasmid pIN32 demonstrates complex genetic instability and phenotypic plasticity.
• Environmental conditions, such as temperature, can induce significant alterations in plasmid characteristics.
• These findings contribute to understanding plasmid evolution and their role in bacterial adaptation.