First Report of the Plasmid-mediated fosB Gene in Enterococcus faecalis from Pigs.

Xiaoming Wang,Jinhu Huang,Yi Gao,Liping Wang,Xiao Liu,Naiyan Sun

doi:10.3390/genes12111684

Abstract

Plasmid-mediated fosfomycin determinants is a global public health concern due to the increasing dissemination of fosfomycin resistance and limited clinical treatment options. Information about the fosfomycin resistant and molecular genetic among Enterococcus spp. is still lacking. In this study, we found the first plasmid-medieted fosB in Enterococcus faecalis from pigs, and all the fosfomycin resistant Enterococcus spp. (FRE) isolates were multi-drug resistant. S1-PFGE, Southern blot and conjugation experiments indicated that the fosB gene located on ~54.7 kb transferable plasmids. Relative competition assay confirmed that the fosB-carrying plasmid impaired fitness in recipient E. faecalis JH2-2. Illumina and the MinION sequencing data revealed that both E. faecalis ES-1 and ES-2 isolates belonged to novel ST (ST964), and had 71 SNPs difference. WGS showed that the genetic environments of fosB were diverse among different species, and the linezolid resistance gene optrA was found in the fosB-carrying strains. To summarize, for the first time, we reported plasmid-mediated fosB in E. faecalis from pigs. And, the co-occurrence of fosB and optrA pose a serious threat to public health.

Highlights

MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Citation: Wang, X.; Gao, Y.; Liu, X.; Abstract: Plasmid-mediated fosfomycin determinants is a global public health concern due to the increasing dissemination of fosfomycin resistance and limited clinical treatment options
The isolation rates of fosfomycin resistant E. faecalis and E. faecium from pigs were 7.67% and 7.12%, respectively, which were higher than 0.3% in E. faecalis and 4.9% in E. faecium, respectively, from a China teaching hospital [10]
It was found that most fosfomycin reof 10 sistance Enterococcus isolates were negative for the known fos genes, indicated that 4novel fosfomycin resistance determinants or murA mutations may exist among these isolates

Summary

Introduction

MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Citation: Wang, X.; Gao, Y.; Liu, X.; Abstract: Plasmid-mediated fosfomycin determinants is a global public health concern due to the increasing dissemination of fosfomycin resistance and limited clinical treatment options. We found the first plasmid-medieted fosB in Enterococcus faecalis from pigs, and all the fosfomycin resistant Enterococcus spp. As a broad-spectrum cell wall synthesis inhibitor, fosfomycin interferes with the first step of bacterial cell wall biosynthesis, the formation of the peptidoglycan precursor UDP N-acetylmuramic acid, and inhibits of enzymecatalyzed reaction [6]. It has considerable bactericidal activity against a range of bacteria by virtue of specific antimicrobial mechanisms [7]. FosB, which catalyzes L-cysteine-fosfomycin, was currently the only known plasmid-brone fosfomycinresistance determinant in Enterococcus spp.

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