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First isolation of an IMP-1 metallo-β-lactamase-producing Kluyvera ascorbata in Japan
Takeaki Wajima1, Yuji Hirai2, Takayuki Otake1
1Department of Microbiology, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
Objectives:
The emergence of carbapenemase-producing Enterobacterales has been increasing globally, causing growing concerns. Although Kluyvera ascorbata is not known as a metallo-β-lactamase (MBL)-producer, in the present study we isolated a K. ascorbata strain producing IMP-1 MBL from catheter-associated urine of a paediatric patient and performed whole-genome analysis to elucidate the features of this strain and the origin of IMP-1.
Methods:
Carbapenemase production was confirmed by a modified carbapenemase inactivation method. Whole-genome sequencing was performed using NovaSeq 6000 and GridION. Conjugation ability was evaluated using Escherichia coli ML1410 by a broth mating assay.
Results:
TheblaIMP-1 gene was located on a 149 316-bp transferable plasmid (pKATP2) and formed a class 1 integron structure. In addition, this plasmid had two types of repA genes as well as astA encoding a putative heat-stable enterotoxin. Comparison with other plasmids from Enterobacterales and Pseudomonas aeruginosa suggested that this plasmid might have originated by the integration of multiple plasmids. In addition, pKATP2 harboured conjugation-associated genes and was transferable.
Conclusion:
This is the first report of MBL-producing K. ascorbata. Therefore, our findings suggest that species which do not typically produce MBL could acquire the corresponding genes, attracting attention as potential MBL-producing pathogens.
Insights
This study reports the first isolation of metallo-β-lactamase (MBL)-producing Kluyvera ascorbata from a pediatric patient. The findings highlight the potential for non-MBL-producing species to acquire MBL genes, posing a growing public health concern.
Area of Science:
- Microbiology
- Genomics
- Infectious Diseases
Background:
- Rising global concern over carbapenemase-producing Enterobacterales.
- Kluyvera ascorbata is not typically known as a metallo-β-lactamase (MBL)-producer.
Purpose of the Study:
- To report the first isolation of an MBL-producing Kluyvera ascorbata strain.
- To perform whole-genome analysis to understand the strain's features and the origin of IMP-1 MBL.
- To investigate the transferability of the MBL-producing plasmid.
Main Methods:
- Isolation of K. ascorbata from catheter-associated urine.
- Confirmation of carbapenemase production using a modified carbapenemase inactivation method.
- Whole-genome sequencing and conjugation ability evaluation.
Main Results:
- TheblaIMP-1 gene was found on a transferable plasmid (pKATP2) with a class 1 integron structure.
- The plasmid contained two repA genes and astA, and likely originated from the integration of multiple plasmids.
- The plasmid harbored conjugation-associated genes and was transferable.
Conclusions:
- This is the first report of MBL-producing K. ascorbata.
- Species not typically producing MBLs can acquire these genes.
- Such strains represent potential emerging pathogens requiring attention.
