Phenotypic and genotypic characterization of vancomycin-resistant Enterococcus faecium clinical isolates from two hospitals in Mexico: First detection of VanB phenotype-vanA genotype.

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.

Phenotypic and genotypic characterization of vancomycin-resistant Enterococcus faecium clinical isolates from two hospitals in Mexico: First detection of VanB phenotype-vanA genotype / Caracterización fenotípica y genotípica de aislamientos clínicos de Enterococcus faecium resistente a vancomicina de 2 hospitales en México: primera detección del fenotipo VanB-genotipo vanA

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