ABSTRACT
Vancomycin-resistant Enterococcus faecium (E. faecium) infection is associated with higher mortality rates. Previous studies have emphasized the importance of innate immune cells and signalling pathways in clearing E. faecium, but a comprehensive analysis of host-pathogen interactions is lacking. Here, we investigated the interplay of host and E. faecium in a murine model of septic peritonitis. Following injection with a sublethal dose, we observed significantly increased murine sepsis score and histological score, decreased weight and bacterial burden, neutrophils and macrophages infiltration, and comprehensive activation of cytokine-mediated signalling pathway. In mice receiving a lethal dose, hypothermia significantly improved survival, reduced bacterial burden, cytokines, and CD86 expression of MHC-II+ recruited macrophages compared to the normothermia group. A mathematical model constructed by observational data from 80 animals, recapitulated the host-pathogen interplay, and further verified the benefits of hypothermia. These findings indicate that E. faecium triggers a severe activation of cytokine-mediated signalling pathway, and hypothermia can improve outcomes by reducing bacterial burden and inflammation.
Subject(s)
Cytokines , Disease Models, Animal , Enterococcus faecium , Gram-Positive Bacterial Infections , Host-Pathogen Interactions , Peritonitis , Sepsis , Vancomycin-Resistant Enterococci , Animals , Peritonitis/microbiology , Peritonitis/immunology , Mice , Gram-Positive Bacterial Infections/immunology , Gram-Positive Bacterial Infections/microbiology , Vancomycin-Resistant Enterococci/pathogenicity , Sepsis/microbiology , Sepsis/immunology , Cytokines/metabolism , Mice, Inbred C57BL , Macrophages/immunology , Macrophages/microbiology , Signal TransductionABSTRACT
OBJECTIVE: To describe a clonal outbreak due to vancomycin-resistant Enterococcus faecium (VREF) in the nephrology and renal transplant unit of a tertiary teaching hospital in Barcelona, Spain, and to highlight how active patient and environment surveillance cultures, as well as prompt and directed intervention strategies, mainly environmental, helped to successfully bring it under control. PATIENTS AND METHODS: A study was conducted on patients admitted to the nephrology ward with any culture positive for VREF over a 6-month period (August 2012-January 2013). Based on the identification of a clonal link between the isolates, weekly rectal screening using swabs was implemented for all patients, as well as environmental cultures and cleaning of medical equipment and the ward. VREF isolates were identified by MicroScan and confirmed by Etest. Bacterial identification was confirmed by MALDI-TOF MS. The presence of van genes, and esp and hyl virulence genes was determined using PCR. The clonal relationship between the isolates was studied first with DiversiLab (bioMérieux), and then by PFGE-Smal and MLST. A two-tier sequence of infection control measures was implemented. RESULTS: During the study period, VREF was isolated from 13 patients. All cases were colonized with no criteria for infection. VREF isolates were also extensively recovered from the environment and medical equipment. Isolates carried the vanA gene, and were multidrug-resistant, including high-level resistance (MIC >16mg/L) to vancomycin and teicoplanin. Molecular analysis showed that all VREF isolates belonged to sequence type 17 (ST17) carrying hyl virulence genes. After implementing infection control measures in a two-tier sequence, and reinforcing particularly environmental and medical equipment cleaning, no further cases were detected in the follow-up year. CONCLUSION: A clonal outbreak of VREF-ST17 involving only colonization is reported. The prompt implementation of aggressive infection control measures in patients and the environment was effective in controlling the outbreak and avoided the potential emergence of infection among patients
OBJETIVO: Describir un brote clonal de Enterococcus faecium resistente a vancomicina (VREF) en la unidad de trasplante renal de un hospital universitario en Barcelona (España) y destacar que los controles ambientales, así como las estrategias de intervención dirigidas y tempranas, principalmente ambientales, fueron suficientes para controlar el brote. PACIENTES Y MÉTODOS: Se estudiaron todos los pacientes ingresados en la unidad de nefrología con un cultivo positivo para VREF en un periodo de 6 meses (Agosto de 2012 a Enero de 2013). Basados en la identificación de una relación clonal entre las cepas, se implementaron frotis rectales de cribado para todos los pacientes, así como frotis ambientales y limpieza de todo el material médico y de la unidad. Se identificaron las cepas de VREF por MicroScan y se confirmaron con Etest. La identificación bacteriana se confirmó con MALDI-TOF MS. La presencia de genes van, y de genes de virulencia esp y hyl, se investigó por PCR. La relación clonal entre las cepas se estudió con DiversiLab (bioMérieux), y después con PFGE-Smal y MLST. RESULTADOS: Durante el periodo estudiado, se aislaron cepas de VREF de 13 pacientes. Todos fueron casos de colonización sin casos de infección. Se aislaron numerosas cepas del ambiente y del equipo médico. Las cepas presentaban el gen VanA y eran multirresistentes. El análisis molecular mostró que todas las cepas pertenecían a la secuencia tipo17 (ST17), portando genes de virulencia hyl. Tras la implementación de medidas de control de infección de 2 niveles, e incrementando sobretodo la limpieza del ambiente y del equipo médico, no se detectaron nuevos casos en el año posterior. CONCLUSIÓN: Se informa de un brote clonal de VREF-ST17. La pronta implementación de medidas agresivas de control de infección en pacientes y en el ambiente fue efectiva para el control del brote
Subject(s)
Humans , Vancomycin-Resistant Enterococci/pathogenicity , Cross Infection/prevention & control , Kidney Transplantation , Infection Control/organization & administration , Vancomycin Resistance , Enterococcus faecalis/pathogenicity , Disease Outbreaks/prevention & controlABSTRACT
INTRODUCTION: Enterococcus faecium has emerged as a multidrug-resistant nosocomial pathogen involved in outbreaks worldwide. Our aim was to determine the antimicrobial susceptibility, biofilm production, and clonal relatedness of vancomycin-resistant E. faecium (VREF) clinical isolates from two hospitals in Mexico. METHODS: Consecutive clinical isolates (n=56) were collected in two tertiary care hospitals in Mexico from 2011 to 2014. VREF isolates were characterized by phenotypic and molecular methods including pulsed-field gel electrophoresis (PFGE). RESULTS: VREF isolates were highly resistant to vancomycin, erythromycin, norfloxacin, high-level streptomycin, and teicoplanin, and showed lower resistance to tetracycline, nitrofurantoin and quinupristin-dalfopristin. None of the isolates were resistant to linezolid. The vanA gene was detected in all isolates. Two VanB phenotype-vanA genotype isolates, highly resistant to vancomycin and susceptible to teicoplanin, were detected. Furthermore, 17.9% of the isolates were classified as biofilm producers, and the espfm gene was found in 98.2% of the isolates. A total of 37 distinct PFGE patterns and 6 clones (25% of the isolates as clone A, 5.4% as clone B, and 3.6% each as clone C, D, E, and F) were detected. Clone A was detected in 5 different wards of the same hospital during 14 months of surveillance. CONCLUSION: The high resistance to most antimicrobial agents and the moderate cross-transmission of VREF detected accentuates the need for continuous surveillance of E. faecium in the hospital setting. This is also the first reported incidence of the E. faecium VanB phenotype-vanA genotype in the Americas
INTRODUCCIÓN: Enterococcus faecium multifarmacorresistente es un importante patógeno intrahospitalario que a nivel mundial se ha asociado con brotes hospitalarios. El objetivo de este trabajo fue determinar la susceptibilidad a los antimicrobianos, la formación de biopelícula y la relación clonal de los aislamientos clínicos de Enterococcus faecium resistentes a vancomicina (EFRV) en México. MÉTODOS: Se recolectaron 56 aislamientos clínicos en 2 hospitales mexicanos de 2011 a 2014. Los aislamientos de EFRV fueron caracterizados por métodos fenotípicos y moleculares. RESULTADOS: Los aislamientos de EFRV fueron resistentes a vancomicina, eritromicina, norfloxacina, estreptomicina de alto nivel y teicoplanina. Presentaron baja resistencia a tetraciclina, nitrofurantoína y quinupristina-dalfopristina. Ningún aislamiento presentó resistencia a linezolid. El gen vanA se detectó en todos los aislamientos. Dos aislamientos presentaron un fenotipo VanB-genotipo vanA, que se caracteriza por la resistencia a vancomicina y la susceptibilidad a teicoplanina. El 17,9% de los aislamientos fueron productores de biopelícula y el 98,2% presentaron el gen espfm. Se obtuvieron 37 patrones de bandas diferentes y 6 clonas (25% de la clona A, 5,4% de la clona B y 3,6% de las clonas C, D, E y F, respectivamente). La clona A se detectó en 5 diferentes salas hospitalarias en el mismo hospital durante 14meses. CONCLUSIÓN: La alta resistencia a los antimicrobianos, junto con la moderada transmisión cruzada de EFRV encontradas en este estudio, acentúan, la necesidad de una vigilancia continua de este microorganismo en el ambiente hospitalario. Además, este es el primer reporte de E. faeciumcon un fenotipo VanB-genotipo vanA en América
Subject(s)
Humans , Enterococcus faecium/pathogenicity , Vancomycin-Resistant Enterococci/pathogenicity , Phenotype , Genotyping Techniques/methods , Drug Resistance, Multiple , Vancomycin Resistance , Gram-Positive Bacterial Infections/drug therapy , Clonal EvolutionABSTRACT
La resistencia de los microorganismos grampositivos a los antimicrobianos clásicos y nuevos implica retos terapéuticos. En España la resistencia a la meticilina de Staphylococcus aureus (25-30%) y de los estafilococos coagulasa negativa (50-60%) se ha estabilizado en la última década. En los enterococos, la resistencia a la vancomicina es inferior al 5%. Tanto linezolid como daptomicina presentan, en general, buena actividad frente a estos microorganismos. Sin embargo, en las unidades de cuidados intensivos, son preocupantes la resistencia de Staphylococcus epidermidis a linezolid (20,9%) y de Enterococcus faecium a daptomicina (10,5%) (AU)
Resistance among Gram-positive microorganisms to classical and new antimicrobials is a therapeutic threat. In Spain, methicillin resistance among Staphylococcus aureus (25-30%) and coagulase-negative staphylococci (50-60%) seems to have stabilized in the last decade. Among enterococci, vancomycin resistance is less than 5%. Both linezolid and daptomycin, in general, show good activity against these microorganisms. However, the resistance rates of Staphylococcus epidermidis to linezolid (20.9%), and of Enterococcus faecium to daptomycin (10.5%) in isolates from intensive care units are a worrying (AU)