Glycopeptide-resistant Enterococcus Faecium Research Articles

Platanosides from Platanus × acerifolia: New molecules, SAR, and target validation of a strong lead for drug-resistant bacterial infections and the associated sepsis

Three undescribed (1–3) and nine known (4–12) platanosides were isolated and characterized from a bioactive extract of the May leaves of Platanus × acerifolia that initially showed inhibition against Staphylococcus aureus. Targeted compound mining was guided by an LC-MS/MS-based molecular ion networking (MoIN) strategy combined with conventional isolation procedures from a unique geographic location. The novel structures were mainly determined by 2D NMR and computational (NMR/ECD calculations) methods. Compound 1 is a rare acylated kaempferol rhamnoside possessing a truxinate unit. 6 (Z,E-platanoside) and 7 (E,E-platanoside) were confirmed to have remarkable inhibitory effects against both methicillin-resistant S. aureus (MIC: ≤ 16 μg/mL) and glycopeptide-resistant Enterococcus faecium (MIC: ≤ 1 μg/mL). These platanosides were subjected to docking analyses against FabI (enoyl-ACP reductase) and PBP1/2 (penicillin binding protein), both of which are pivotal enzymes governing bacterial growth but not found in the human host. The results showed that 6 and 7 displayed superior binding affinities towards FabI and PBP2. Moreover, surface plasmon resonance studies on the interaction of 1/7 and FabI revealed that 7 has a higher affinity (KD = 1.72 μM), which further supports the above in vitro data and is thus expected to be a novel anti-antibacterial drug lead.

N-Terminal guanidine derivatives of teicoplanin antibiotics strongly active against glycopeptide resistant Enterococcus faecium.

Antibiotic resistance is one of the major challenges in healthcare of our time. To meet this challenge, we designed and prepared guanidine and lipophilic guanidine derivatives of the glycopeptide antibiotic teicoplanin to armed them with activity against the most threatening nosocomial bacteria, multiresistant enterococci. From teicoplanin and its pseudoaglycone, a series of N-terminal guanidine derivatives have been prepared with free and amide C-terminal parts. Six aliphatic and aromatic lipophilic carbodiimides were prepared and used for the synthesis of lipophilic guanidine teicoplanin conjugates. All new N-terminal guanidine antibiotics showed high activity against a standard panel of Gram-positive bacteria. Four selected derivatives displayed excellent antibacterial activity against a series of nosocomial VanA Enterococcus faecium strains.

Emerging extensively drug-resistant bacteria (eXDR) in France in 2018

ObjectiveThis 2018 report of Healthcare-Associated Infections Early Warning and Response System (HAI-EWRS) notifications of carbapenemase-producing Enterobacteriaceae (CPE) or glycopeptide-resistant Enterococcus faecium (GRE), and of strains analysed by the National Reference Center for anti-microbial resistance (NRC) aimed to describe the epidemiology of emerging extensively drug-resistant bacteria (eXDR) in France and control measures implemented in hospital settings. Patients and methodsAll HAI-EWRS notifications of eXDR received at the national level and all eXDR strains received at the NRC between January 1, 2018 and January 31, 2018 were analysed. Variables analysed were number of cases, number of strains, resistance mechanism, sample type, link with a foreign country, and control measures implemented. ResultsIn 2018, 1704 CPE notifications and 315 GRE notifications were reported in France, with an increasing trend since 2012 (×6 for CPE, ×3 for GRE), from respectively 364 and 155 hospitals (+66% for CPE, +57% for GRE since 2012). eXDR strains were mainly isolated from rectal screening swabs. Notifications with patients receiving standard precautions were more often associated with outbreaks than notifications with patients receiving contact precautions at admission. NRC received 2674 CPE strains and 775 GRE strains in 2018 (×8.3 and ×2.8 compared with 2012). ConclusionThe increasing annual number of eXDR notifications and eXDR strains received by the NRC is multifactorial but reflects a worrying spread of eXDR in France. The number of infections remains low, but this article shows that existing recommendations are not fully implemented.

The use of high-throughput sequencing to investigate an outbreak of glycopeptide-resistant Enterococcus faecium with a novel quinupristin-dalfopristin resistance mechanism

High-throughput sequencing (HTS) has successfully identified novel resistance genes in enterococci and determined clonal relatedness in outbreak analysis. We report the use of HTS to investigate two concurrent outbreaks of glycopeptide-resistant Enterococcus faecium (GRE) with an uncharacterised resistance mechanism to quinupristin-dalfopristin (QD). Seven QD-resistant and five QD-susceptible GRE isolates from a two-centre outbreak were studied. HTS was performed to identify genes or predicted proteins that were associated with the QD-resistant phenotype. MLST and SNP typing on HTS data was used to determine clonal relatedness. Comparative genomic analysis confirmed this GRE outbreak involved two distinct clones (ST80 and ST192). HTS confirmed the absence of known QD resistance genes, suggesting a novel mechanism was conferring resistance. Genomic analysis identified two significant genetic determinants with explanatory power for the high level of QD resistance in the ST80 QD-resistant clone: an additional 56aa leader sequence at the N-terminus of the lsaE gene and a transposon containing seven genes encoding proteins with possible drug or drug-target modification activities. However, HTS was unable to conclusively determine the QD resistance mechanism and did not reveal any genetic basis for QD resistance in the ST192 clone. This study highlights the usefulness of HTS in deciphering the degree of relatedness in two concurrent GRE outbreaks. Although HTS was able to reveal some genetic candidates for uncharacterised QD resistance, this study demonstrates the limitations of HTS as a tool for identifying putative determinants of resistance to QD.

Efficiency of different control measures for preventing carbapenemase-producing enterobacteria and glycopeptide-resistant Enterococcus faecium outbreaks: a 6-year prospective study in a French multihospital institution, January 2010 to December 2015.

An infection control programme was implemented in a 21,000-bed multihospital institution for controlling the spread of carbapenemase-producing Enterobacteriaceae (CPE) and glycopeptide-resistant Enterococcus faecium (GRE), classified as ‘emergent extensively drug-resistant bacteria’ (eXDR) in France. We evaluated factors associated with outbreaks occurrence (n = 103), which followed 901 eXDR introductions (index case followed or not by secondary cases) from 2010 to 2015. In univariate analysis, knowing that patients had been hospitalised abroad, bacterial species (GRE vs CPE, as well as the CPE Klebsiella pneumoniae compared with the other Enterobacteriaceae species) and type of measures implemented within the first 2 days of hospitalisation were associated with outbreaks occurrence, but not the type of wards where carriers were hospitalised, nor the eXDR colonisation or infection status. In multivariate analysis, occurrence of outbreaks was significantly lower when contact precautions (odds ratio (OR): 0.34; 95% confidence interval (CI): 0.22–0.54) and even more when dedicated nursing staff (OR: 0.09; 95% CI: 0.02–0.39) were implemented around eXDR index cases within the first 2 days of hospitalisation (p < 10 − 3). GRE introductions were more frequently associated with occurrence of outbreaks than CPE (OR: 3.58; 95% CI: 2.32–5.51, p < 10 − 3). A sustained and coordinated strategy is efficient to limit the spread of eXDR at the scale of a large health institution.

VanA Mediated Glycopeptide Resistant Enterococcus faecium (GRE) Infection in an Elderly Patient with Chronic Kidney Disease – A Case Report

VanA Mediated Glycopeptide Resistant Enterococcus faecium (GRE) Infection in an Elderly Patient with Chronic Kidney Disease – A Case Report

First outbreak of colonization by linezolid- and glycopeptide-resistant Enterococcus faecium harbouring the cfr gene in a UK nephrology unit

To describe an outbreak of colonization by linezolid- and glycopeptide-resistant Enterococcus faecium harbouring the cfr gene in a UK nephrology unit. Isolates of linezolid-resistant E.faecium were typed by pulsed-field gel electrophoresis (PFGE), and examined by polymerase chain reaction (PCR) and sequencing for the transmissible cfr gene that confers resistance to linezolid. Enhanced environmental cleaning, initial and weekly screening of all patients, and monitoring of adherence to standard infection control precautions were implemented. Five patients with pre-existing renal disease were found to have rectal colonization with linezolid-resistant E.faecium over a two-week period. The index case was a 57-year-old male from India who had travelled to the UK. One patient also had a linezolid-resistant E.faecium of a different PFGE profile isolated from a heel wound. All isolates were confirmed to harbour the cfr gene by PCR and Sanger sequencing, and all were resistant to glycopeptides (VanA phenotype). This article describes the first UK outbreak with a single strain of linezolid- and glycopeptide-resistant E.faecium harbouring the cfr gene, affecting five patients in a nephrology unit. Following the implementation of aggressive infection control measures, no further cases were detected beyond a two-week period.

TREATMENT CHALLENGES IN ENTEROCOCCUS FAECIUM SEPSIS AND CLOSTRIDIUM DIFFICILE DIARRHEA IN A PATIENT WITH B-CELL NON-HODGKIN LYMPHOMA – CASE REPORT

The risk of developing secondary infections in immunocompromised patients due to hematological malignancies and the treatments for such conditions is very well known. Fever can be the only manifestation of a serious infection among this category of patients. The degree and duration of neutropenia is directly related to the risk of multiple infectious complications. When we are dealing with severely impaired host defenses virtually any microorganism can become invasive, bacteria (gram-positive pathogens, but gram-negative as well), being the greatest immediate threat. Multiple pathogens isolated from an immunocompromised host can represent a major challenge for the clinician, especially when we have to face multidrug resistant (MDR) microorganisms, also called “superbugs”. Besides, when we confront such a patient with many comorbidities and a high risk for MDR pathogens infection, we also confront with a lot of limitations in terms of treatment options. We present a complicated case of glycopeptide-resistant Enterococcus faecium sepsis secondary to Clostridium difficile colitis in a 63 years old female patient with B-cell non-Hodgkin Lymphoma (NHL) during the R-CHOP therapy.

Les bactéries à Gram positives multirésistantes : probabilités de résistance ? Que craindre ?

Antibiotic resistance in Gram-positive bacteria already has a significant impact on morbidity and mortality. The situation is particularly alarming in the case of methicillin-resistant Staphylococcus aureus and glycopeptide-resistant Enterococcus faecium, which have shown an ability to spread to new ecological niches and to generate new clones with both increased drug resistance and increased virulence. The potential for genetic exchanges between these two species raises the specter of highly resistant and virulent S. aureus strains.

Outbreak in a haematology unit involving an unusual strain of glycopeptide-resistant Enterococcus faecium carrying both vanA and vanB genes

To report an outbreak due to an unusual strain of Enterococcus faecium containing both the vanA and vanB genes, in France, where the rate of glycopeptide-resistant enterococci (GRE) is below 1%. Cases were patients infected or colonized with GRE on the haematology ward. Contact patients were screened by real-time PCR performed on rectal swabs. Clinical features were compared for GRE-positive and GRE-negative patients. GRE isolates were characterized by phenotypic and molecular methods including PFGE. Conjugation experiments were performed to identify van genetic support. After the index patient presented a bacteraemia with vanA/vanB E. faecium, 56 contact patients were screened, 7 of whom were found to be GRE positive: 6 additional cases with vanA/vanB E. faecium and 1 with GRE carrying vanA only. PFGE confirmed the clonal relationship of the seven vanA/vanB E. faecium strains, whereas the vanA isolate was distinct. Only the vanA gene could be transferred to enterococcal recipients by conjugation, and it was probably localized on a mobile genetic element. All isolates were resistant to vancomycin (MIC > 256 mg/L) and teicoplanin (MIC = 24-32 mg/L), but were susceptible to tigecycline (MIC = 0.09 mg/L), linezolid (MIC = 0.75 mg/L) and daptomycin (MIC = 1-2 mg/L). Significant differences (P < 0.001) between carriers and non-carriers of GRE were observed for the median duration of hospitalization (57 days versus 16.5 days) and of neutropenia (40 days versus 6 days), the median number of antibiotics used (5 versus 1.5) and the duration of glycopeptide treatment (14.5 days versus 0 days). vanA/vanB E. faecium strains, although rare, can emerge in the absence of previous outbreaks of vanA-GRE or vanB-GRE.

Emergence of glycopeptide resistant Enterococcus faecium in Algeria: a case report

A glycopeptide-resistant Enterococcus faecium (EFRG) was isolated from a wound in a patient hospitalized in a university hospital in Algiers. This strain was resistant to several antibiotics. This patient was carrying this strain in the digestive tract which may partly explain its origin. Genotypic comparison of the two strains by pulsed field gel electrophoresis showed that it was the same strain. Glycopeptide resistance was due to the presence of the vanA gene. Vigilance is required facing the emergence of strains of EFRG in our hospitals.

Control of a regional outbreak of vanA glycopeptide-resistant Enterococcus faecium, Eastern France, 2004–2009

At the end of 2004, an outbreak of glycopeptide-resistant enterococci (GRE) spread from the Nancy Teaching Hospital to more than 40 facilities in the Lorraine region. Because this outbreak appeared to be uninhibited, a regional task force was set up to organize and co-ordinate the management of the outbreak, visiting the affected facilities to publicize the existing recommendations and take stock of the problems encountered in the field. The task force then proposed control measures specific to the region. The proposed measures included promoting the use of alcohol-based hand-rub solutions, isolation measures, enhanced screening policies, cohorting GRE-colonized patients and contacts in special wards with dedicated staff where possible, or failing that, isolating them in single rooms with additional "contact" precautions, maintaining these precautions for GRE-colonized patients until a negative stool sample was obtained after antibiotic treatment (which is a more restrictive definition of "cleared" than usually employed), regional co-ordination of the follow-up of GRE-colonized patients with the weekly publication of a list of institutions that were or had been affected to allow isolation measures to be adopted as soon as known-GRE-colonized patient were readmitted. It was not possible to determine the efficacy of each individual measure on the course of the outbreak. Nevertheless, we observed that the number of new GRE-colonized patients started to decrease following their implementation. Ultimately, 1077 GRE colonizations were recorded in Lorraine, and the outbreak is now under control.

Retrospective evidence for a biological cost of vancomycin resistance determinants in the absence of glycopeptide selective pressures

ObjectivesTo estimate the relative fitness differences between glycopeptide-resistant Enterococcus faecium (GREF) and glycopeptide-susceptible E. faecium (GSEF) from yearly surveillance data on the occurrence of GREF in Danish poultry farm environments.MethodsA population genetic model was adapted to retrospectively estimate the biological fitness cost of acquired resistance. Maximization of a likelihood function was used to predict the longitudinal persistence of acquired resistance.ResultsOur analysis suggests strong selection against GREF following the 1995 ban on the glycopeptide growth promoter avoparcin. However, parameterizing the model with two selection coefficients suggesting a reduced negative effect of the acquired resistance on bacterial fitness over time significantly improved the fit of the model. Our analyses suggest that the acquired glycopeptide resistance will persist for >25 years.ConclusionsAcquired resistance determinants in commensal E. faecium populations in Danish farm environments are likely to persist for decades, even in the absence of glycopeptide use.

Molecular Characterization of Glycopeptide-Resistant Enterococci from Hospitals of the Picardy Region (France)

We studied 138 glycopeptide-resistant enterococci (GRE) strains, consisting of 131 glycopeptide-resistant Enterococcus faecium (GREfm) and 7 glycopeptide-resistant Enterococcus faecalis (GREfs). The GREfm strains were resistant to penicillin, ampicillin, vancomycin, and teicoplanin, while the GREfs strains were only resistant to vancomycin and teicoplanin. The van A gene was the only glycopeptide determinant present in all GRE isolates investigated. Genes coding for Hyl and Hyl+ Esp were detected in 39 (29.8%) and 92 (70.2%) of the 131 GREfm isolates, respectively. Three of the 7 GREfs were positive for gelE+asa 1 genes, 3 for gel E gene, and 1 for asa 1 gene. The genetic relationship between the 138 GRE was analyzed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). GREfm isolates were clustered in a single genogroup (pulsotype A), and GREfs were clustered in six genogroups (pulsotypes B-G). Among the isolates investigated by MLST, only 18 PCR products were sequenced (12 E. faecium and 6 E. faecalis), and 9 sequence types (STs) were identified.

Relevance of hot spots in the evolution and transmission of Tn1546 in glycopeptide-resistant Enterococcus faecium (GREF) from broiler origin

Glycopeptide-resistant enterococci are still present within the broiler sector, despite the EU ban of avoparcin more than a decade ago. In the present study, we have developed a rapid method for screening the flanking regions at the integration point of Tn1546 in glycopeptide-resistant Enterococcus faecium isolated from broiler farms. Total DNA was digested, ligated and amplified using primers from inside Tn1546. The resulting amplicons were purified and sequenced. Two new primers were designed based on obtained sequences. Two main insertion points have been repeatedly found in isolates from the UK (n = 150). The first insertion point revealed that 25 isolates harboured Tn1546 positioned in a sequence with 96% homology to a streptomycin adenyltransferase gene (AY604739) from a Staphylococcus intermedius plasmid. At this insertion point, a direct repeat (GTCCT) was duplicated as previously described, indicating transposition at the target site. Furthermore, this 'hot spot' was also detected in isolates from Norway (2/8) and Denmark (17/20). The second insertion point detected in 45 isolates from the UK revealed integration into an Inc18-like plasmid, most likely by a process of target site recombination. The presence of a common insertion point for isolates from different geographical areas could suggest the insertion of Tn1546 by transposition in a plasmid-specific site, followed by genetic rearrangement both inside the transposon and in the flanking regions.

Complete sequence of Enterococcus faecium pVEF3 and the detection of an ω-ε-ζ toxin–antitoxin module and an ABC transporter

Glycopeptide resistant Enterococcus faecium (GREF) persists on Norwegian poultry farms despite the ban on the growth promoter avoparcin. The biological basis for long-term persistence of avoparcin resistance is not fully understood. This study presents the complete DNA sequence of the E. faecium R-plasmid pVEF3 and functional studies of some plasmid-encoded traits (a toxin–antitoxin (TA) system and an ABC transporter) that may be of importance for plasmid persistence. The pVEF3 (63.1 kbp), isolated from an E. faecium strain of poultry origin sampled in Norway in 1999, has 71 coding sequences including the vanA avoparcin/vancomycin resistance encoding gene cluster. pVEF3 encodes the TA system ω-ε-ζ, and plasmid stability tests and transcription analysis show that ω-ε-ζ is functional in Enterococcus faecalis OGIX, although with decreasing effect over time. The predicted ABC transporter was not found to confer reduced susceptibility to any of the 28 substances tested. The TA system identified in the pVEF-type plasmids may contribute to vanA plasmid persistence on Norwegian poultry farms. However, size and compositional heterogeneity among E. faecium vanA plasmids suggest that additional plasmid maintenance systems in combination with host specific factors and frequent horizontal gene transfer and rearrangement causes the observed plasmid composition and distribution patterns.

Linezolid treatment of glycopeptide-resistant Enterococcus faecium in very low birth weight premature neonates

Glycopeptide-resistant Enterococcus faecium has emerged as an important nosocomial pathogen with limited therapeutic options. Here we report the successful treatment of glycopeptide-resistant E. faecium infection in two very low birth weight premature infants with the new oxazolidinone linezolid. Treatment with linezolid at a dosage of 10 mg/kg every 8 h intravenously for a duration of 16 days and 14 days, respectively, was well tolerated and led to complete clinical recovery and clearance of the organism from all body sites. The two cases support the clinical efficacy and safety of linezolid in very low birth weight premature neonates with glycopeptide-resistant E. faecium infections.

Prevalence, persistence, and molecular characterization of glycopeptide-resistant enterococci in Norwegian poultry and poultry farmers 3 to 8 years after the ban on avoparcin.

Environmental reservoirs of glycopeptide-resistant enterococci (GRE) in Norway have been linked to former growth promoting use of the glycopeptide avoparcin in poultry production. We have examined the prevalence of fecal GRE in poultry and poultry farmers 3 to 8 years after the Norwegian avoparcin ban in 1995 and performed molecular analyses of the GRE population. Fecal samples from poultry farmers and their flocks on 29 previously avoparcin-exposed farms were collected on five occasions during the study period (1998 to 2003). All flocks (100%) were GRE positive in 1998. Throughout the study period, 78.5% of the poultry samples were GRE positive. Glycopeptide-resistant Enterococcus faecium (GREF) was isolated from 27.6% of the farmer samples in 1998 and from 27.8% of the samples collected between 1998 and 2003. The prevalence of fecal GRE in poultry declined significantly during the study period, but prevalence in samples from the farmers did not decline. PCR analysis revealed a specific Tn1546-plasmid junction fragment in 93.9% of E. faecium isolates. A putative postsegregation killing (PSK) system linked to Tn1546 was detected in 97.1% of the isolates examined. Multilocus sequence typing of glycopeptide-susceptible (n = 10) and -resistant (n = 10) E. faecium isolates from humans (n = 10) and poultry (n = 10) on two farms displayed 17 different sequence types. The study confirms the continuing persistence of a widespread common plasmid-mediated vanA-pRE25-PSK element within a heterogeneous GRE population on Norwegian poultry farms 8 years after the avoparcin ban. Moreover, it suggests an important role of PSK systems in the maintenance of antimicrobial resistance determinants in reservoirs without apparent antimicrobial selection.

Dutch Guideline for Preventing Nosocomial Transmission of Highly Resistant Microorganisms (HRMO)

Hospitals are faced with the increasingly rapid emergence and dissemination of antimicrobial-resistant microorganisms. US and European guidelines on the prevention of antimicrobial resistance in hospitals were, until recently, mainly directed at methicillin-resistant Staphylococcus aureus (MRSA). In 2004, the Dutch Working Party on Infection Prevention issued a guideline on the prevention of nosocomial transmission of highly resistant microorganisms (HRMO), in order to fulfill the growing need for additional guidance on the control of other pathogens with acquired resistance and the potential to spread within hospitals (such as glycopeptide-resistant Enterococcus faecium, penicillin-resistant Streptococcus pneumoniae, extendedspectrum beta-lactamase producing Enterobacteriaceae, and other (multi)drug-resistant gram-negatives). In addition to providing criteria for defining HRMO, the Dutch guideline provides recommendations on isolation of patients, active surveillance, and contact tracing. The guideline will enable the comparison of HRMO rates between hospitals, and may be used to evaluate the efficacy of programs to control antibiotic use and/or nosocomial transmission of resistant pathogens. The eventual success of nationwide implementation of this guideline remains to be established in the coming years.

Clonality AmongEnterococcus faeciumClinical Isolates

In the course of a survey to determine the epidemiology of enterococcal infections in Italy, a sudden increment, in a 1-year time, was noted in the number of glycopeptide resistant Enterococcus faecium isolated from different wards of the University Hospital in Rome, Italy. The isolates were characterized for clonal relatedness by comparing SmaI gel electropherotypes, presence of vancomycin-resistance genes, and expression of virulence factors. PFGE identified in a single pulsed type all the glycopeptide-resistant isolates but one. Resistance to high levels of aminoglycosides was expressed by these same isolates, which also included a majority of non biofilm-forming strains. Two esp gene-carrying strains were also identified in different PFGE types. Data indicates that a specific clone acquired, in the clinical setting, the genetic determinant for glycopeptide resistance, thus improving environmental adaptation and favoring its persistence and spread.