Identification of a Novel Hybrid Plasmid Encoding KPC-2 and Virulence Factors in Klebsiella pneumoniae Sequence Type 11

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a growing global health threat.
• The co-existence of carbapenem resistance genes and virulence plasmids in CRKP complicates treatment strategies.
• Emergence of hybrid plasmids combining resistance and virulence factors presents a novel challenge.

Purpose of the Study:

• To characterize a novel hybrid plasmid (pCRHV-C2244) identified in a clinical CRKP strain.
• To investigate the genetic features, transmissibility, and functional impact of this hybrid plasmid.
• To assess the plasmid's contribution to bacterial virulence and stability.

Main Methods:

• Plasmid isolation and characterization from a clinical ST11-K64 CRKP isolate.
• Conjugation experiments to assess plasmid transmissibility (mobilizability).
• In vitro and in vivo assays to evaluate bacterial virulence and plasmid stability.

Main Results:

• A novel hybrid plasmid, pCRHV-C2244, harboring both blaKPC-2 (carbapenem resistance) and pLVPK-like virulence determinants was identified.
• pCRHV-C2244 is non-self-transmissible but mobilizable with a helper plasmid.
• The plasmid significantly enhanced virulence and demonstrated stable maintenance in the host strain with minimal fitness cost.

Conclusions:

• The identified hybrid plasmid pCRHV-C2244 represents a significant clinical threat due to its combined resistance and virulence properties.
• Understanding the characteristics of such hybrid plasmids is crucial for developing effective therapeutic and control strategies against CRKP.
• The stable maintenance and enhanced virulence conferred by pCRHV-C2244 underscore the need for continued surveillance of emerging resistance and virulence mechanisms in K. pneumoniae.