Complete nucleotide sequence of a conjugative plasmid carrying bla(PER-1)

Area of Science:

• Microbiology
• Genomics
• Molecular Biology

Background:

• Vibrio parahaemolyticus is a significant marine bacterium with implications for public health.
• The emergence of antimicrobial resistance in bacteria is a global concern.
• Plasmids play a crucial role in the dissemination of resistance genes.

Purpose of the Study:

• To determine the complete nucleotide sequence of the self-transmissible plasmid pVPH1 from Vibrio parahaemolyticus.
• To characterize the genetic elements within pVPH1, particularly those associated with multidrug resistance.
• To elucidate the mechanism of bla(PER-1) gene dissemination mediated by pVPH1.

Main Methods:

• Whole-genome sequencing of the plasmid pVPH1.
• Comparative genomic analysis with related plasmids (pAQU1, pAQU2).
• Identification and characterization of mobile genetic elements, including integrons and insertion sequences.

Main Results:

• The nucleotide sequence of pVPH1 was determined, revealing a size of 183,730 bp.
• pVPH1 shares a similar backbone to pAQU1 and pAQU2 but contains a distinct ~40-kb multidrug resistance (MDR) region.
• A complex class 1 integron (ISCR1-bla(PER-1)-gst-abct-qacEΔ1-sul1) was identified, forming a circular intermediate crucial for bla(PER-1) dissemination.

Conclusions:

• The genetic makeup of pVPH1, particularly its MDR region and complex integron, provides insights into antimicrobial resistance mechanisms in Vibrio parahaemolyticus.
• The identified circular intermediate highlights a novel mechanism for the spread of the bla(PER-1) gene.
• Understanding plasmid-mediated gene transfer is essential for developing strategies to combat bacterial infections and resistance.