Hypervirulence and carbapenem resistance: two distinct evolutionary directions that led high-risk Klebsiella pneumoniae clones to epidemic success

ABSTRACT

Introduction: Over the past few decades, Klebsiella pneumoniae has become a significant threat to public health and is now listed as an ESKAPE pathogen. Evolving with versatile capabilities, K. pneumoniae is a population composed of genetically and phenotypically diverse bacteria. However, epidemic K. pneumoniae are restricted to specific clonal lineages. The clonal group CG23 comprises hypervirulent K. pneumoniae displaying limited resistance to antimicrobials and is frequently associated with the community-acquired invasive syndrome. On the other hand, CG258 is another clonal group of K. pneumoniae that has evolved resistance to carbapenems, primarily by acquiring the carbapenemase-encoding genes through nosocomial carriage.

Areas covered: With a focus on the high-risk K. pneumoniae clonal lineages CG23 and CG258, we review recent advances including the newly discovered lineage-specific genomic features, and the molecular basis of K. pneumoniae-associated epidemiology, antimicrobial resistance, and hypervirulence.

Expert opinion: Both CG23 and CG258 can establish reservoirs in susceptible individuals. Empirical antimicrobial regimens that are prescribed for immediate treatments frequently create selective pressures that favor the high-risk lineages to develop into prominent colonizers. This dilemma reinforces the need for effective therapies that require rapid and accurate diagnosis of epidemic K. pneumoniae.

KEYWORDS:

• Klebsiella pneumoniae
• hypervirulence
• CG23
• carbapenemase-producing
• CG258

Article highlights

• Equipped with hypervirulence or carbapenem resistance leads high-risk K. pneumoniae clones to epidemic success.

• CG23 was a high-risk clonal group associated with hypervirulence.

• CG23-I was a successful sublineage of HvKP which carried the genomic features associated with hypervirulence, including KL1 cps locus, ICEKp10, and the large virulence plasmid.

• Predominant lineages of carbapenemase-producing K. pneumoniae evolved from the clonal group CG258 and exhibited geographic variations

• Genomic variations on the cps locus frequently occur and are associated with distinct lineages of CG258

• CG307, an emerging high-risk clone, may pose a new threat to public health.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewers Disclosure

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Additional information

Funding

This paper was not funded.