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Microbiology Spectrum Jul 2019Enterococci are unusually well adapted for survival and persistence in a variety of adverse environments, including on inanimate surfaces in the hospital environment and... (Review)
Review
Enterococci are unusually well adapted for survival and persistence in a variety of adverse environments, including on inanimate surfaces in the hospital environment and at sites of infection. This intrinsic ruggedness undoubtedly played a role in providing opportunities for enterococci to interact with other overtly drug-resistant microbes and acquire additional resistances on mobile elements. The rapid rise of antimicrobial resistance among hospital-adapted enterococci has rendered hospital-acquired infections a leading therapeutic challenge. With about a quarter of a genome of additional DNA conveyed by mobile elements, there are undoubtedly many more properties that have been acquired that help enterococci persist and spread in the hospital setting and cause diseases that have yet to be defined. Much remains to be learned about these ancient and rugged microbes, particularly in the area of pathogenic mechanisms involved with human diseases.
Topics: Animals; Enterococcus; Gram-Positive Bacterial Infections; Humans; Interspersed Repetitive Sequences; Virulence
PubMed: 31298205
DOI: 10.1128/microbiolspec.GPP3-0053-2018 -
Medicina Oral, Patologia Oral Y Cirugia... May 2019The main cause of endodontic failure is the persistence of microorganisms that cause an intraradicular or extratradicular infection and that become resistant to... (Review)
Review
BACKGROUND
The main cause of endodontic failure is the persistence of microorganisms that cause an intraradicular or extratradicular infection and that become resistant to disinfection measures. The objective of this review is to identify the microbiota associated with endodontic failure, as well as the reasons why these microorganisms are capable of surviving basic disinfection measures.
MATERIAL AND METHODS
Systematic search of scientific articles in the databases PubMed with the following keywords "Endodontic Infections", "Endodontic Microbiology", "Endodontic Failure", "Enterococcus Faecalis", "Endodontics Retreatment" was carried out. Case reports and articles with publication date prior to 2000 were not included in this review.
RESULTS
Most authors highlight E. faecalis as the main microorganism associated with endodontic failure, nevertheless there are recent studies that isolate, to a greater extent, other bacteria such as Fusobacterium nucleatum and Propionibacterium.
DISCUSSION
These microorganisms have in common the following proprieties, which make them able to escape the disinfection measures: the ability to form a biofilm, to locate in areas unreachable to root canal instrumentation techniques, synergism, the ability to express survival genes and activate alternative metabolic pathways.
Topics: Bacteria; Biofilms; Dental Pulp Cavity; Enterococcus faecalis; Root Canal Therapy
PubMed: 31041915
DOI: 10.4317/medoral.22907 -
Infectious Disease Clinics of North... Dec 2020Serious infections owing to vancomycin-resistant enterococci have historically proven to be difficult clinical cases, requiring combination therapy and management of... (Review)
Review
Serious infections owing to vancomycin-resistant enterococci have historically proven to be difficult clinical cases, requiring combination therapy and management of treatment-related toxicity. Despite the introduction of new antibiotics with activity against vancomycin-resistant enterococci to the therapeutic armamentarium, significant challenges remain. An understanding of the factors driving the emergence of resistance in vancomycin-resistant enterococci, the dynamics of gastrointestinal colonization and microbiota-mediated colonization resistance, and the mechanisms of resistance to the currently available therapeutics will permit clinicians to be better prepared to tackle these challenging hospital-associated pathogens.
Topics: Anti-Bacterial Agents; Cross Infection; Drug Resistance, Multiple, Bacterial; Enterococcus faecium; Gastrointestinal Microbiome; Gram-Positive Bacterial Infections; Humans; Vancomycin-Resistant Enterococci
PubMed: 33131572
DOI: 10.1016/j.idc.2020.08.004 -
Microbial Genomics Jul 2019Vancomycin-resistant Enterococcus faecium (VREfm) is a globally significant public health threat and was listed on the World Health Organization's 2017 list of... (Review)
Review
Vancomycin-resistant Enterococcus faecium (VREfm) is a globally significant public health threat and was listed on the World Health Organization's 2017 list of high-priority pathogens for which new treatments are urgently needed. Treatment options for invasive VREfm infections are very limited, and outcomes are often poor. Whole-genome sequencing is providing important new insights into VREfm evolution, drug resistance and hospital adaptation, and is increasingly being used to track VREfm transmission within hospitals to detect outbreaks and inform infection control practices. This mini-review provides an overview of recent data on the use of genomics to understand and respond to the global problem of VREfm.
Topics: Disease Outbreaks; Enterococcus faecium; Genome, Bacterial; Genomics; Gram-Positive Bacterial Infections; Humans; Phylogeny; Vancomycin Resistance; Vancomycin-Resistant Enterococci; Whole Genome Sequencing
PubMed: 31329096
DOI: 10.1099/mgen.0.000283 -
Clinical Microbiology Reviews Mar 2019The genus comprises a ubiquitous group of Gram-positive bacteria that are of great relevance to human health for their role as major causative agents of health... (Review)
Review
The genus comprises a ubiquitous group of Gram-positive bacteria that are of great relevance to human health for their role as major causative agents of health care-associated infections. The enterococci are resilient and versatile species able to survive under harsh conditions, making them well adapted to the health care environment. Two species cause the majority of enterococcal infections: and Both species demonstrate intrinsic resistance to common antibiotics, such as virtually all cephalosporins, aminoglycosides, clindamycin, and trimethoprim-sulfamethoxazole. Additionally, a remarkably plastic genome allows these two species to readily acquire resistance to further antibiotics, such as high-level aminoglycoside resistance, high-level ampicillin resistance, and vancomycin resistance, either through mutation or by horizontal transfer of genetic elements conferring resistance determinants.
Topics: Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Enterococcus; Gene Transfer, Horizontal; Gram-Positive Bacterial Infections; Humans; Microbial Sensitivity Tests; Mutation
PubMed: 30700430
DOI: 10.1128/CMR.00058-18 -
Science (New York, N.Y.) Oct 2020Ionizing radiation causes acute radiation syndrome, which leads to hematopoietic, gastrointestinal, and cerebrovascular injuries. We investigated a population of mice...
Ionizing radiation causes acute radiation syndrome, which leads to hematopoietic, gastrointestinal, and cerebrovascular injuries. We investigated a population of mice that recovered from high-dose radiation to live normal life spans. These "elite-survivors" harbored distinct gut microbiota that developed after radiation and protected against radiation-induced damage and death in both germ-free and conventionally housed recipients. Elevated abundances of members of the bacterial taxa and were associated with postradiation restoration of hematopoiesis and gastrointestinal repair. These bacteria were also found to be more abundant in leukemia patients undergoing radiotherapy, who also displayed milder gastrointestinal dysfunction. In our study in mice, metabolomics revealed increased fecal concentrations of microbially derived propionate and tryptophan metabolites in elite-survivors. The administration of these metabolites caused long-term radioprotection, mitigation of hematopoietic and gastrointestinal syndromes, and a reduction in proinflammatory responses.
Topics: Acute Radiation Syndrome; Animals; Clostridiales; Enterococcaceae; Fatty Acids, Volatile; Gastrointestinal Microbiome; Humans; Metabolomics; Mice; Mice, Inbred C57BL; Radiation Protection; Survivors; Tryptophan
PubMed: 33122357
DOI: 10.1126/science.aay9097 -
Microbiology Spectrum Jul 2018Enterococci are natural inhabitants of the intestinal tract in humans and many animals, including food-producing and companion animals. They can easily contaminate the... (Review)
Review
Enterococci are natural inhabitants of the intestinal tract in humans and many animals, including food-producing and companion animals. They can easily contaminate the food and the environment, entering the food chain. Moreover, is an important opportunistic pathogen, especially the species and , causing a wide variety of infections. This microorganism not only contains intrinsic resistance mechanisms to several antimicrobial agents, but also has the capacity to acquire new mechanisms of antimicrobial resistance. In this review we analyze the diversity of enterococcal species and their distribution in the intestinal tract of animals. Moreover, resistance mechanisms for different classes of antimicrobials of clinical relevance are reviewed, as well as the epidemiology of multidrug-resistant enterococci of animal origin, with special attention given to beta-lactams, glycopeptides, and linezolid. The emergence of new antimicrobial resistance genes in enterococci of animal origin, such as and , is highlighted. The molecular epidemiology and the population structure of and isolates in farm and companion animals is presented. Moreover, the types of plasmids that carry the antimicrobial resistance genes in enterococci of animal origin are reviewed.
Topics: Animals; Anti-Infective Agents; Drug Resistance, Bacterial; Drug Resistance, Multiple, Bacterial; Enterococcus; Enterococcus faecalis; Enterococcus faecium; Farms; Food Microbiology; Gastrointestinal Tract; Gram-Positive Bacterial Infections; Humans; Molecular Epidemiology; Pets
PubMed: 30051804
DOI: 10.1128/microbiolspec.ARBA-0032-2018 -
Scientific Reports Dec 2020The aim of this study was to investigate how carbohydrates (glucose or sucrose) affect the characteristics of Enterococcus faecalis (E. faecalis) planktonic and biofilm...
The aim of this study was to investigate how carbohydrates (glucose or sucrose) affect the characteristics of Enterococcus faecalis (E. faecalis) planktonic and biofilm in vitro. For this study, E. faecalis was cultured in tryptone-yeast extract broth with 0% glucose + 0% sucrose, 0.5% glucose, 1% glucose, 0.5% sucrose, or 1% sucrose. Viability of E. faecalis was examined by colony forming unit counting assays. Biofilm formation was assessed by measuring extracellular DNA (eDNA), a component of the biofilm matrix. Quantitative real-time PCR (qRT-PCR) was performed to investigate the expression of virulence-associated genes. Field emission scanning electron microscopy analysis, confocal laser scanning microscopy analysis, and crystal violet colorimetric assay were conducted to study E. faecalis biofilms. E. faecalis showed the highest viability and eDNA levels in 1% sucrose medium in biofilms. The result of qRT-PCR showed that the virulence-associated genes expressed highest in 1% sucrose-grown biofilms and in 1% glucose-grown planktonic cultures. E. faecalis showed highly aggregated biofilms and higher bacteria and exopolysaccharide (EPS) bio-volume in sucrose than in 0% glucose + 0% sucrose or glucose. The results indicate that the production of eDNA and EPS and expression of virulence-associated genes in E. faecalis are affected by the concentration of carbohydrates in biofilm or planktonic culture.
Topics: Culture Media; Enterococcus faecalis; Extracellular Polymeric Substance Matrix; Microbial Viability; Virulence
PubMed: 33318537
DOI: 10.1038/s41598-020-78998-5 -
Microbiology Spectrum Mar 2019The study of the genetics of enterococci has focused heavily on mobile genetic elements present in these organisms, the complex regulatory circuits used to control their... (Review)
Review
The study of the genetics of enterococci has focused heavily on mobile genetic elements present in these organisms, the complex regulatory circuits used to control their mobility, and the antibiotic resistance genes they frequently carry. Recently, more focus has been placed on the regulation of genes involved in the virulence of the opportunistic pathogenic species and . Little information is available concerning fundamental aspects of DNA replication, partition, and division; this article begins with a brief overview of what little is known about these issues, primarily by comparison with better-studied model organisms. A variety of transcriptional and posttranscriptional mechanisms of regulation of gene expression are then discussed, including a section on the genetics and regulation of vancomycin resistance in enterococci. The article then provides extensive coverage of the pheromone-responsive conjugation plasmids, including sections on regulation of the pheromone response, the conjugative apparatus, and replication and stable inheritance. The article then focuses on conjugative transposons, now referred to as integrated, conjugative elements, or ICEs, and concludes with several smaller sections covering emerging areas of interest concerning the enterococcal mobilome, including nonpheromone plasmids of particular interest, toxin-antitoxin systems, pathogenicity islands, bacteriophages, and genome defense.
Topics: Anti-Bacterial Agents; Bacteriophages; Conjugation, Genetic; DNA Transposable Elements; Drug Resistance, Bacterial; Enterococcus; Enterococcus faecalis; Humans; Signal Transduction; Vancomycin-Resistant Enterococci; Virulence
PubMed: 30848235
DOI: 10.1128/microbiolspec.GPP3-0055-2018 -
The Journal of Antimicrobial... 2015Enterococcus faecalis (Efc) and Enterococcus faecium (Efm) are frequently resistant to vancomycin and β-lactams (BLs). In vitro data suggest synergy between several BLs...
OBJECTIVES
Enterococcus faecalis (Efc) and Enterococcus faecium (Efm) are frequently resistant to vancomycin and β-lactams (BLs). In vitro data suggest synergy between several BLs and glycopeptides or lipopeptides against resistant pathogens. Our objective was to conduct combination MIC and time-kill experiments to evaluate BL synergy with daptomycin against enterococci.
METHODS
Fifteen Efc and 20 Efm strains were evaluated for daptomycin enhancement via combination MICs. Daptomycin MICs were obtained by microdilution in the absence and presence of ceftaroline, ertapenem, cefepime, ceftriaxone, cefotaxime, cefazolin and ampicillin. Two Efc strains (R6981 and R7808) and one isogenic daptomycin-susceptible/daptomycin-non-susceptible Efm pair (8019/5938) were evaluated in time-kill experiments. Daptomycin at 0.5 × MIC was used in combination with BL at biological free concentration. Strain 5938 was evaluated for enhancement of daptomycin binding in fluorescently labelled daptomycin (BoDipy) experiments.
RESULTS
Ceftaroline reduced daptomycin MIC values the most against all strains. In time-kill experiments, ceftaroline, ertapenem, cefepime, ceftriaxone and ampicillin demonstrated synergy with daptomycin against all strains, cefazolin demonstrated none and cefotaxime demonstrated synergy against only R7808. Bacterial reduction at 24 h was greater for daptomycin + ceftaroline, ertapenem, cefepime, ceftriaxone or ampicillin for all strains compared with any single agent or daptomycin + cefazolin or cefotaxime (P < 0.001). In BoDipy daptomycin experiments, ceftaroline enhanced daptomycin binding most compared with all other agents (P < 0.001).
CONCLUSIONS
The data support the potential use of daptomycin/BL combination therapy in infections caused by VRE. Combination regimens, other than those involving cefazolin and cefotaxime, provide better kill compared with daptomycin alone. Further clinical research involving daptomycin combinations is warranted.
Topics: Daptomycin; Drug Synergism; Enterococcus faecalis; Enterococcus faecium; Humans; Microbial Sensitivity Tests; Microbial Viability; Vancomycin-Resistant Enterococci; beta-Lactams
PubMed: 25645208
DOI: 10.1093/jac/dkv007