Cryptic plasmids isolated from Campylobacter strains represent multiple, novel incompatibility groups

Area of Science:

• Microbiology
• Genetics
• Molecular Biology

Background:

• Campylobacter species are significant foodborne pathogens.
• Multi-drug resistant (MDR) strains pose a growing public health threat.
• Cryptic plasmids in Campylobacter are poorly understood but may be valuable genetic tools.

Purpose of the Study:

• To sequence and characterize cryptic plasmids from MDR Campylobacter strains.
• To assess the potential of these plasmids for developing novel Campylobacter shuttle vectors.
• To contribute to the classification of Campylobacter cryptic plasmids into incompatibility (Inc) groups.

Main Methods:

• Whole-genome sequencing of four cryptic plasmids from Campylobacter coli RM2228 and Campylobacter jejuni RM1170.
• Bioinformatic analysis to determine plasmid replication mechanisms and Inc groups.
• Comparative analysis with existing characterized Campylobacter plasmids.

Main Results:

• Sequencing revealed three plasmids from C. coli and one from C. jejuni.
• One plasmid showed similarity to Firmicutes RepL family plasmids (rolling-circle replication).
• Three plasmids were identified as iteron-containing plasmids (ICPs), with two representing a novel Inc group.
• Comparison suggested up to nine Inc groups for Campylobacter cryptic plasmids.
• The characterized plasmids possess features (small size, unique restriction sites, novel Inc groups) suitable for shuttle vector construction.

Conclusions:

• The sequenced cryptic plasmids represent valuable resources for developing next-generation Campylobacter shuttle vectors.
• These novel vectors could enable the transformation of environmental Campylobacter isolates.
• Further classification of Campylobacter plasmids into Inc groups is needed.