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Characterization of an NDM-5-producing hypervirulent Klebsiella pneumoniae sequence type 65 clone from a lung
Jiankang Zhao1, Yulin Zhang1, Yanyan Fan1
1Laboratory of Clinical Microbiology and Infectious Diseases, Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, National Clinical Research Center for Respiratory Diseases, Beijing, People's Republic of China.
Abstract:
The emergence of New Delhi Metallo-β-lactamase (NDM)-producing Klebsiella pneumoniae has aroused critical concern worldwide. Herein, we reported the first emergence of NDM-5-producing K. pneumoniae isolates in a 68-year-old lung transplant recipient, who died of septic shock 13 days after surgery. The K. pneumoniae strain KP22937 isolated from the bloodstream of the patient was analyzed for phenotypes and genotypes. KP22937 belonged to sequence type (ST) 65 and capsule serotype K2, contained iucABCDiutA and iroBCDN virulence clusters, showed high virulence to mice, and was therefore considered a hypervirulent K. pneumoniae. The blaNDM-5 gene was located on a genomic island region of the IncX3-type plasmid pNDM22937, which was successfully transferred to Escherichia coli EC600 with insignificant fitness costs. The transconjugant demonstrated similar antimicrobial susceptibility and growth kinetics to the recipient E. coli EC600. The plasmid pNDM22937 was almost identical to the blaNDM-5-carrying IncX3 plasmids previously reported in K. pneumoniae strains with different ST types and in other species. Our findings raise concerns about the horizontal spread of blaNDM-5 gene mediated by IncX3 plasmid, where hypervirulent K. pneumoniae strains are also involved. Stricter control measures are needed to prevent the dissemination of the novel clone in hospital settings.
Insights
The first New Delhi Metallo-β-lactamase (NDM)-5 producing hypervirulent Klebsiella pneumoniae strain was identified in a lung transplant recipient. This strain, carrying the blaNDM-5 gene on an IncX3 plasmid, highlights concerns of antimicrobial resistance spread.
Area of Science:
- Microbiology
- Infectious Diseases
- Genetics
Background:
- New Delhi Metallo-β-lactamase (NDM)-producing Klebsiella pneumoniae poses a significant global health threat due to its resistance to carbapenems.
- Hypervirulent Klebsiella pneumoniae strains are increasingly recognized for their ability to cause severe infections.
Observation:
- The first isolation of NDM-5 producing Klebsiella pneumoniae (strain KP22937) from a lung transplant recipient who succumbed to septic shock.
- KP22937 was identified as a hypervirulent strain belonging to sequence type 65 and capsule serotype K2, possessing key virulence factors.
Findings:
- The blaNDM-5 gene was located on an IncX3 plasmid (pNDM22937), which was efficiently transferred to Escherichia coli with minimal fitness cost.
- The transconjugant E. coli exhibited similar antimicrobial susceptibility and growth characteristics to the parent strain.
- The IncX3 plasmid carrying blaNDM-5 showed high similarity to previously reported plasmids, suggesting a conserved mechanism for gene dissemination.
Implications:
- The findings underscore the critical risk of horizontal gene transfer of blaNDM-5 via IncX3 plasmids, particularly involving hypervirulent Klebsiella pneumoniae.
- Urgent implementation of stricter infection control measures is necessary to curb the spread of this emerging multidrug-resistant clone in healthcare settings.
