DNA fingerprinting of conjugative plasmids incompatible with R6K (IncX)

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Conjugative plasmids are key vectors for horizontal gene transfer in bacteria.
• The IncX incompatibility group is a significant plasmid group with implications for antibiotic resistance spread.
• Understanding plasmid diversity is crucial for tracking bacterial evolution and managing infectious diseases.

Purpose of the Study:

• To characterize the genetic diversity of IncX conjugative plasmids.
• To compare plasmids from different bacterial hosts and geographical origins.
• To assess the variability in molecular size and DNA fingerprint patterns within the IncX group.

Main Methods:

• Plasmid DNA isolation from various bacterial hosts.
• Restriction endonuclease digestion using enzymes like EcoRI, EcoRV, BamHI, BglI, BglII, PstI, and SalI.
• DNA fingerprinting analysis to compare fragment patterns.

Main Results:

• Fourteen conjugative plasmids were identified as IncX group members, using R6K as a reference.
• Plasmids exhibited a wide range of molecular sizes, from 39 kb to 77 kb.
• DNA fingerprinting revealed significant variations in fragment patterns, indicating substantial genetic diversity.

Conclusions:

• IncX plasmids, despite sharing close genetic relatedness (transfer and incompatibility), display considerable diversity in size and DNA structure.
• The observed variability suggests ongoing evolution and adaptation within the IncX plasmid group.
• These findings contribute to a better understanding of plasmid diversity and evolution in bacterial populations.