In:
Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 65, No. 4 ( 2021-03-18)
Abstract:
We recently identified a novel plasmid-mediated resistance-nodulation-division (RND)-type efflux pump gene cluster, tmexCD1-toprJ1 , in Klebsiella pneumoniae that conferred resistance to multiple antimicrobials, including tigecycline. While homologs of tmexCD1-toprJ1 were found encoded in many other bacterial species in GenBank, their functions and transfer mechanisms remain unknown. This study identified another mobile gene cluster, tmexCD2-toprJ2 , co-occurring on both a plasmid (pHNNC189-2) and the chromosome of a clinical Raoultella ornithinolytica isolate, strain NC189, producing KPC-2, NDM-1, and RmtC. tmexCD2-toprJ2 shares high similarity at the nucleotide level with tmexCD1-toprJ1 , with 98.02%, 96.75%, and 99.93% identities to tmexC1 , tmexD1 , and toprJ1 , respectively. Phylogenetic analysis revealed that tmexCD2-toprJ2 may have originated from the chromosome of a Pseudomonas species. The expression of tmexCD2-toprJ2 in an Escherichia coli strain resulted in an 8-fold increase in the tigecycline MIC and decreased susceptibility to other antimicrobials. Genetic context analyses demonstrated that tmexCD2-toprJ2 , together with the adjacent hypothetical site-specific integrase genes, was possibly captured and mobilized by a XerD-like tyrosine recombinase system, forming a putative transposition unit ( xerD -like- int3 -like- thf2-ybjD-umuD- Δ umuC1 - int1 -like- int2 -like- hp1-hp2-tnfxB2- IS Bvi2-tmexCD2-toprJ2- Δ umuC1 ), which was inserted into umuC- like genes in both the NC189 plasmid pHNNC189-2 and the chromosome. Since tmexCD1-toprJ1 and tmexCD2-toprJ2 could confer multidrug resistance, the spread of these gene clusters, associated with the new recombinase system, calls for more attention.
Type of Medium:
Online Resource
ISSN:
0066-4804
,
1098-6596
DOI:
10.1128/AAC.02229-20
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2021
detail.hit.zdb_id:
1496156-8
SSG:
12
SSG:
15,3
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