In:
Microbiology Spectrum, American Society for Microbiology, Vol. 11, No. 3 ( 2023-06-15)
Abstract:
The aim of this study was to investigate the transferability of acquired linezolid resistance genes and associated mobile genetic elements in an Enterococcus faecalis isolate QZ076, cocarrying optrA , cfr , cfr (D), and poxtA2 genes. MICs were determined by broth microdilution. Whole-genome sequencing (WGS) was performed using the Illumina and Nanopore platforms. The transfer of linezolid resistance genes was investigated by conjugation, using E. faecalis JH2-2 and clinical methicillin-resistant Staphylococcus aureus (MRSA) 109 as recipients. E. faecalis QZ076 harbors four plasmids, designated pQZ076-1 to pQZ076-4, with optrA located in the chromosomal DNA. The gene cfr was located on a novel pseudocompound transposon, designated Tn 7515 , integrated into the 65,961-bp pCF10-like pheromone-responsive conjugative plasmid pQZ076-1. Tn 7515 generated 8-bp direct target duplications (5′- GATACGTA -3′). The genes cfr (D) and poxtA2 were colocated on the 16,397-bp mobilizable broad-host-range Inc18 plasmid pQZ076-4. The cfr -carrying plasmid pQZ076-1 could transfer from E. faecalis QZ076 to E. faecalis JH2-2, along with the cfr (D)- and poxtA2 -cocarrying plasmid pQZ076-4, conferring the corresponding resistant phenotype to the recipient. Moreover, pQZ076-4 could also transfer to MRSA 109. To the best of our knowledge, this study presented the first report of four acquired linezolid resistance genes [ optrA , cfr , cfr (D), and poxtA2 ] being simultaneously present in the same E. faecalis isolate. The location of the cfr gene on a pseudocompound transposon in a pheromone-responsive conjugative plasmid will accelerate its rapid dissemination. In addition, the cfr -carrying pheromone-responsive conjugative plasmid in E. faecalis was also able to mobilize the interspecies transfer of the cfr (D)- and poxtA2 -cocarrying plasmid between enterococci and staphylococci. IMPORTANCE In this study, the simultaneous occurrence of four acquired oxazolidinone resistance genes [ optrA , cfr , cfr (D), and poxtA2 ] was identified in an E. faecalis isolate of chicken origin. The association of the cfr gene with a novel pseudocompound transposon Tn 7515 integrated into a pCF10-like pheromone-responsive conjugative plasmid will accelerate its dissemination. Moreover, the location of the resistance genes cfr (D) and poxtA2 on a mobilizable broad-host-range Inc18 family plasmid represents the basis for their intra- and interspecies dissemination with the aid of a conjugative plasmid and further accelerates the spreading of acquired oxazolidinone resistance genes, such as cfr , cfr (D), and poxtA2 , among Gram-positive pathogens.
Type of Medium:
Online Resource
ISSN:
2165-0497
DOI:
10.1128/spectrum.02741-22
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2023
detail.hit.zdb_id:
2807133-5
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