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For a One-Health investigation of antimicrobial resistance (AMR) in Enterococcus spp., isolates from humans and beef cattle along with abattoirs, manured fields, natural streams, and wastewater from both urban and cattle feedlot sources were collected over two years. Species identification of Enterococcus revealed distinct associations across the continuum. Of the 8430 isolates collected, Enterococcus faecium and Enterococcus faecalis were the main species in urban wastewater (90%) and clinical human isolates (99%); Enterococcus hirae predominated in cattle (92%) and feedlot catch-basins (60%), whereas natural streams harbored environmental Enterococcus spp. Whole-genome sequencing of E. faecalis (n = 366 isolates) and E. faecium (n = 342 isolates), revealed source clustering of isolates, indicative of distinct adaptation to their respective environments. Phenotypic resistance to tetracyclines and macrolides encoded by tet(M) and erm(B) respectively, was prevalent among Enterococcus spp. regardless of source. For E. faecium from cattle, resistance to β-lactams and quinolones was observed among 3% and 8% of isolates respectively, compared to 76% and 70% of human clinical isolates. Clinical vancomycin-resistant E. faecium exhibited high rates of multi-drug resistance, with resistance to all β-lactam, macrolides, and quinolones tested. Differences in the AMR profiles among isolates reflected antimicrobial use practices in each sector of the One-Health continuum.

Background Currently, there is no agreed standard for exploring the antimicrobial activity of wound antiseptics in a phase 2/ step 2 test protocol. In the present study, a standardised in-vitro test is proposed, which allows to test potential antiseptics in a more realistically simulation of conditions found in wounds as in a suspension test. Furthermore, factors potentially influencing test results such as type of materials used as test carrier or various compositions of organic soil challenge were investigated in detail. Methods This proposed phase 2/ step 2 test method was modified on basis of the EN 14561 by drying the microbial test suspension on a metal carrier for 1 h, overlaying the test wound antiseptic, washing-off, neutralization, and dispersion at serial dilutions at the end of the required exposure time yielded reproducible, consistent test results. Results The difference between the rapid onset of the antiseptic effect of PVP-I and the delayed onset especially of polihexanide was apparent. Among surface-active antimicrobial compounds, octenidine was more effective than chlorhexidine digluconate and polihexanide, with some differences depending on the test organisms. However, octenidine and PVP-I were approximately equivalent in efficiency and microbial spectrum, while polihexanide required longer exposure times or higher concentrations for a comparable antimicrobial efficacy. Conclusion Overall, this method allowed testing and comparing differ liquid and gel based antimicrobial compounds in a standardised setting.

Background Enterococcus is ubiquitous in nature and is a commensal of both the bovine and human gastrointestinal (GI) tract. It is also associated with clinical infections in humans. Subtherapeutic administration of antibiotics to cattle selects for antibiotic resistant enterococci in the bovine GI tract. Antibiotic resistance genes (ARGs) may be present in enterococci following antibiotic use in cattle. If located on mobile genetic elements (MGEs) their dissemination between Enterococcus species and to pathogenic bacteria may be promoted, reducing the efficacy of antibiotics. Results We present a comparative genomic analysis of twenty-one Enterococcus spp. isolated from bovine feces including Enterococcus hirae ( n  = 10), Enterococcus faecium ( n  = 3), Enterococcus villorum ( n  = 2), Enterococcus casseliflavus ( n  = 2), Enterococcus faecalis ( n  = 1), Enterococcus durans ( n  = 1), Enterococcus gallinarum ( n  = 1) and Enterococcus thailandicus ( n  = 1). The analysis revealed E. faecium and E. faecalis from bovine feces share features with human clinical isolates, including virulence factors. The Tn 917 transposon conferring macrolide-lincosamide-streptogramin B resistance was identified in both E. faecium and E. hirae , suggesting dissemination of ARGs on MGEs may occur in the bovine GI tract. An E. faecium isolate was also identified with two integrative conjugative elements (ICEs) belonging to the Tn 916 family of ICE, Tn 916 and Tn 5801 , both conferring tetracycline resistance. Conclusions This study confirms the presence of enterococci in the bovine GI tract possessing ARGs on MGEs, but the predominant species in cattle, E. hirae is not commonly associated with infections in humans. Analysis using additional complete genomes of E. faecium from the NCBI database demonstrated differential clustering of commensal and clinical isolates, suggesting that these strains may be specifically adapted to their respective environments.

Intestinal commensal bacteria can inhibit dense colonization of the gut by vancomycin-resistant Enterococcus faecium (VRE), a leading cause of hospital-acquired infections 1 , 2 . A four-strained consortium of commensal bacteria that contains Blautia producta BP SCSK can reverse antibiotic-induced susceptibility to VRE infection 3 . Here we show that BP SCSK reduces growth of VRE by secreting a lantibiotic that is similar to the nisin-A produced by Lactococcus lactis . Although the growth of VRE is inhibited by BP SCSK and L. lactis in vitro, only BP SCSK colonizes the colon and reduces VRE density in vivo. In comparison to nisin-A, the BP SCSK lantibiotic has reduced activity against intestinal commensal bacteria. In patients at high risk of VRE infection, high abundance of the lantibiotic gene is associated with reduced density of E. faecium . In germ-free mice transplanted with patient-derived faeces, resistance to VRE colonization correlates with abundance of the lantibiotic gene. Lantibiotic-producing commensal strains of the gastrointestinal tract reduce colonization by VRE and represent potential probiotic agents to re-establish resistance to VRE. The gut commensal Blautia producta secretes a lantibiotic that reduces colonization of the gut by the major pathogen vancomycin-resistant Enterococcus faecium , and transplantation of microbiota with high abundance of the lantibiotic gene enhances resistance to colonization in mice.

The rise of antibiotic resistance and a dwindling antimicrobial pipeline have been recognized as emerging threats to public health. The ESKAPE pathogens — Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp. — were initially identified as critical multidrug-resistant bacteria for which effective therapies were rapidly needed. Now, entering the third decade of the twenty-first century, and despite the introduction of several new antibiotics and antibiotic adjuvants, such as novel β-lactamase inhibitors, these organisms continue to represent major therapeutic challenges. These bacteria share several key biological features, including adaptations for survival in the modern health-care setting, diverse methods for acquiring resistance determinants and the dissemination of successful high-risk clones around the world. With the advent of next-generation sequencing, novel tools to track and combat the spread of these organisms have rapidly evolved, as well as renewed interest in non-traditional antibiotic approaches. In this Review, we explore the current epidemiology and clinical impact of this important group of bacterial pathogens and discuss relevant mechanisms of resistance to recently introduced antibiotics that affect their use in clinical settings. Furthermore, we discuss emerging therapeutic strategies needed for effective patient care in the era of widespread antimicrobial resistance.In this Review, Miller and Arias summarize recent advances in understanding ESKAPE pathogens, focusing on their molecular epidemiology, clinical impact, emerging mechanisms of resistance and novel therapeutic approaches.

The opportunistic pathogen Enterococcus faecium colonizes humans and a wide range of animals, endures numerous stresses, resists antibiotic treatment and stubbornly persists in clinical environments. The widespread application of antibiotics in hospitals and agriculture has contributed to the emergence of vancomycin-resistant E. faecium, which causes many hospital-acquired infections. In this Review, we explore recent discoveries about the evolutionary history, the environmental adaptation and the colonization and dissemination mechanisms of E. faecium and vancomycin-resistant E. faecium. These studies provide critical insights necessary for developing novel preventive and therapeutic approaches against vancomycin-resistant E. faecium and also reveal the intricate interrelationships between the environment, the microorganism and the host, providing knowledge that is broadly relevant to how antibiotic-resistant pathogens emerge and endure.This Review explores recent insights into the evolutionary history, the environmental adaptation and the colonization and dissemination mechanisms of Enterococcus faecium, and highlight potential novel preventative and therapeutic approaches to its infections.

Antibiotic-resistant organisms are often found in retail meats, but it has been unclear whether the ingestion of these organisms has any clinical consequences. Resistant strains of E. faecium obtained from raw chicken and pork were ingested by 12 healthy volunteers. Various concentrations of these strains were isolated from stool samples for up to two weeks. This study in 12 healthy volunteers proves that the consumption of resistant enterococci can lead to intestinal carriage of these organisms. The proportion of carriers of glycopeptide-resistant enterococcus species in the general population varies widely from country to country. Values range from 0 percent to a few percent in Sweden, the Netherlands, and the United States 1 – 3 ; 11.8 percent in France 4 ; and up to 28 percent in Belgium. 5 The reasons for the wide variation among countries are not obvious but are probably related to differences in selection pressure. These differences may stem from the use of antimicrobial agents to treat diseases in humans or to promote growth or prevent infection in animals used for food, with the acquisition of . . .

Bacteriocins are antimicrobial peptides that are naturally produced by many bacteria. They hold great potential in the fight against antibiotic resistant bacteria, including ESKAPE pathogens. Engineered live biotherapeutic products (eLBPs) that secrete bacteriocins can be created to deliver targeted bacteriocin production. Here we develop a modular bacteriocin secretion platform that can be used to express and secrete multiple bacteriocins from non-pathogenic Escherichia coli host strains. As a proof of concept we create Enterocin A (EntA) and Enterocin B (EntB) secreting strains that show strong antimicrobial activity against Enterococcus faecalis and Enterococcus faecium in vitro, and characterise this activity in both solid culture and liquid co-culture. We then develop a Lotka-Volterra model that can be used to capture the interactions of these competitor strains. We show that simultaneous exposure to EntA and EntB can delay Enterococcus growth. Our system has the potential to be used as an eLBP to secrete additional bacteriocins for the targeted killing of pathogenic bacteria. Bacteriocins are antimicrobial peptides that are naturally produced by many bacteria. In this work, authors develop a bacteriocin secretion platform, and test, in a proof-of-concept study, antimicrobial efficacy against Enterococcus faecalis and Enterococcus faecium .

Key Points Enterococci are some of the most versatile organisms found to infect hospitalized patients. The epidemiology of enterococcal infections has evolved since the emergence of these pathogens and has seen the rise of Enterococcus faecium as a nosocomial pathogen with serious clinical implications. The effect of antibiotics on the microbiota of the gastrointestinal tract and subsequent alterations in the regulation of the gut immune system can favour colonization by multidrug-resistant enterococci. Enterococcal genomes are extremely malleable, with the ability to exchange large fragments of chromosomal DNA. In addition, the lack of CRISPR (clustered regularly interspaced short palindromic repeats) elements has a potential role in the adaptation of hospital-associated enterococci. Specific pathogenicity factors contribute to the ability of enterococci to produce disease and/or survive in the gastrointestinal tract of mammals. The major factors include secreted and cell surface-associated determinants. Antibiotic resistance is widespread for the anti-enterococcal antibiotics that are most commonly used in clinical practice, and the mechanisms of resistance for many of these antibiotics are known. These antibiotics include ampicillin, linezolid, daptomycin and quinupristin–dalfopristin, and there is also high-level resistance to aminoglycosides. Such resistances have important therapeutic implications. Arias and Murray discuss the factors that may have contributed to the rise of enterococci as nosocomial pathogens, with an emphasis on the epidemiology and pathogenesis of these species and their mechanisms of resistance to the most relevant anti-enterococcal agents used in clinical practice. The genus Enterococcus includes some of the most important nosocomial multidrug-resistant organisms, and these pathogens usually affect patients who are debilitated by other, concurrent illnesses and undergoing prolonged hospitalization. This Review discusses the factors involved in the changing epidemiology of enterococcal infections, with an emphasis on Enterococcus faecium as an emergent and challenging nosocomial problem. The effects of antibiotics on the gut microbiota and on colonization with vancomycin-resistant enterococci are highlighted, including how enterococci benefit from the antibiotic-mediated eradication of Gram-negative members of the gut microbiota. Analyses of enterococcal genomes indicate that there are certain genetic lineages, including an E. faecium clade of ancient origin, with the ability to succeed in the hospital environment, and the possible virulence determinants that are found in these genetic lineages are discussed. Finally, we review the most important mechanisms of resistance to the antibiotics that are used to treat vancomycin-resistant enterococci.

Subclinical mastitis poses a hidden threat to dairy productivity and animal health, often harbouring antimicrobial-resistant pathogens. It is becoming increasingly recognized that Enterococcus species cause mastitis in dairy cows. Accurately characterizing the regional epidemiology of enterococcal mastitis, determining its correlations with management variables, and comprehending its effects on udder health all depend on accurate species information. This study investigated the occurrence, antibiotic resistance and virulence factors of Enterococcus faecalis and Enterococcus faecium in cow dung and milk samples from cows with subclinical mastitis. Subclinical mastitis was identified in 39.0% (68/174) of cows and 27.8% (194/696) of quarters, based on results from the California Mastitis Test (CMT) and somatic cell counts (SCC), respectively. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) and Polymerase Chain Reaction (PCR) targeting the ddl gene confirmed the predominance of E. faecalis (93%) and E. faecium (6.4%) in milk samples, while cow dung samples yielded only E. faecalis (100%). Notably, among the E. faecalis isolates from milk samples, 17.2% exhibited vancomycin resistance, whereas streptomycin resistance was found in a smaller proportion of isolates (6.8%). All (100%) E. faecium isolates from the same milk samples showed resistance to vancomycin. The findings also revealed that 11 (32.3%) of E. faecium isolates from cow dung were resistant to vancomycin. Multidrug resistance (MDR) was observed in 20.6% of milk and 6.8% of cow dung isolates. The vanA gene was the most prevalent antibiotic resistance gene (ARG), detected in 96% of E. faecalis isolates. Virulence profiling of Enterococcus spp. isolates showed varying gene prevalence in milk ( asa1 : 33.3%, ace : 12.7%, esp : 10%) and cow dung samples ( gelE : 53.2%, hyl : 38.2%). This study has indicated a significant occurrence of antimicrobial-resistant E. faecalis and E. faecium strains obtained from subclinical cattle mastitis. These findings emphasize the role of Enterococcus spp., especially vancomycin-resistant strains, as emerging threats in bovine subclinical mastitis, with possible implications for zoonotic transmission and antimicrobial stewardship in dairy systems.