ABSTRACT: Rapid transmission and divergence of ST80 vancomycin-resistant Enterococcus faecium driven by pangenomic variation during the ongoing outbreak
Project description:Genomic analysis of vancomycin-resistant Enterococci isolated from an outbreak of vancomycin-resistant Enterococcus faecium ST80 in Hiroshima, Japan
Project description:A set of small RNAs was identified in Vancomycin-resistant Enterococcus faecium, a leading cause of MDR infections. We described here the function of srn_2050, acting as a T-box riboswitch to regulate expression of downstream genes encoding the HisRS and AspRS aminoacyl-tRNA synthetases. Comparative RNAseq between Aus0004 and isogenic srn_2050 mutant identified the genes whose expression is impacted by the RNA. srn_2050 structure in its ‘off state’ was deciphered by in-line probing, containing T-box consensus sequences, a pseudoknot, a specifier loop and a terminator. Transcription binding assays between the riboswitch and either tRNAAsp or tRNAHis indicate that each deacylated tRNA interacts with the T-box. Their anticodons bind to a GACAC sequence within the specifier loop (GAC and CAC are Asp and His codons, respectively), whereas tRNATyr (UA/C-U) does not. A pioneering evaluation of E. faecium amino acid auxotrophy, with emphasis on E. faecium strain Aus0004, revealed auxotrophy for Histidine but not for Aspartic acid. Based on comparative growths and RNAseq between Aus004 and Aus004-srn2050, the riboswitch is shown essential for growth under aspartate starvation. This is the first example of a functional riboswitch in E. faecium with two overlapping codons allowing a dual tRNA-dependent regulation at transcriptional level.
Project description:This study aims to determine the global gene expression in vancomycin resistant Enterococcus faecium (VRE) in response to a novel essential oil-vancomycin combination, and the individual components (vancomycin, carvacrol and cuminaldehyde) to help determine the mechanism of action of this antimicrobial formulation. This formulation increases the susceptibility of VRE to vancomycin and the array provides data on the synergistic mechanism of action. Five conditions (1. Control; 2. Carvacrol, 1.98 mM; 3. Cuminaldehyde, 4.20 mM; 4. Vancomycin, 0.031 mg/l; 5. Combination, 1.98 mM Carvacrol, 4.2 mM Cuminaldehyde, 0.031 mg/l vancomycin) all with 1% DMSO were tested in triplicate with a 60 minute exposure time before extraction.
Project description:In this study, we aimed to further characterize Ern0160 functions and identify its targets. In silico prediction screen highlighted putative mRNA candidates. For two of them, homologous genes encoding for LysM-containing domain proteins (EFAU004_01059 and EFAU004_01150), we validated a direct and specific interaction to Ern0160. In addition, we found that Ern0160 overexpression was responsible for the repression of the target genes, emphasizing the mode of action of this sRNA. As a recent study provided the role of these genes in the virulence of E. faecium Aus0004 in a mouse model of systemic and urinary tract infections, we proposed that Ern0160 could be part of the regulatory network involved during colonization/infection by attenuating virulence. Furthermore, in vitro tests of antibiotic susceptibility profiles to vancomycin, teicoplanin, daptomycin, ciprofloxacin, and levofloxacin showed that a strain expressing Ern0160 presented lower MICs of fluoroquinolones compared to a ern0160-deleted strains. Very interestingly, we found that a gene implicated in fluoroquinolone resistance in E. faecium, Efmqnr was downregulated when Ern0160 was over-expressed, indicating a link between this sRNA and antibiotic resistance. For the first time, this study investigated throughout the identification of its cellular targets the regulation that could lead to virulence and fluoroquinolone resistance in E. faecium.
Project description:Vancomycin-resistant Enterococcus faecium (VREfm) is a leading cause of healthcare-associated infections globally and demands new approaches for treatment. Here we show that genetic and pharmacological inactivation of a highly conserved NlpC/P60 peptidoglycan hydrolase, secreted antigen A (SagA), enhanced vancomycin susceptibility of VREfm ex vivo and in vivo. Notably, genetic deletion of sagA impaired VREfm peptidoglycan remodeling, growth and increased the activity of vancomycin. We then identified first-in-class covalent NlpC/P60 peptidoglycan hydrolase inhibitors and demonstrated that pharmacological inactivation of SagA activity also impaired peptidoglycan remodeling and increased the efficacy of vancomycin in several VREfm clinical isolates. Our study reveals peptidoglycan hydrolases are druggable targets whose inactivation improves the efficacy of vancomycin against VREfm.
Project description:Protracted transmission and persistence of ST80 vancomycin-resistant Enterococcus faecium clonal complex types CT2933, CT2932 and CT1916 in a large Irish hospital: a 39-month WGS study
| PRJNA1074551 | ENA
Project description:A vanA vancomycin-resistant Enterococcus faecium ST80 outbreak resulting from a single importation event
Project description:In our study, we employed activity-based protein profiling (ABPP), a technique that uses specialized inhibitors to identify active serine hydrolases in different strains of E. faecium (clade A1 and A2) and E. lactis under various growth conditions. Serine hydrolases, a large and diverse family of enzymes that include established drug targets like penicillin-binding proteins, have other less-studied subfamilies. In addition to fluorescent, gel-based profiling, we used a biotin-tagged fluorophosphonate probe for the enrichment and identification of serine hydrolase enzymes via streptavidin enrichment and liquid chromatography/mass spectrometry analysis. This led to the discovery of 11 largely unexplored potential targets (including α,β-hydrolases, SGNH-hydrolases, phospholipases, amidases, and peptidases) that could be exploited for drug developmentagainst the vancomycin-resistant E. faecium strain E745.