Virulence factors in vancomycin-resistant and vancomycin - susceptible Enterococcus faecalis from Brazil

Abstract

Enterococci are members of commensal flora of animals and insects, but are also important opportunistic pathogens. Our objective was to observe if there was any difference of virulence in several groups of E. faecalis, mainly between vancomycin-resistant E. faecalis (VREFS) of colonization and infection. VREFS and vancomycin-sensitive E. faecalis from Brazil were screened for the presence of virulence factor genes. Phenotypic assays were used to assess in vitro expression, to understand the pathogenic potential of these isolates and to determine whether a correlation exists between virulence and antibiotic resistance. Different virulence profiles were found suggesting that the disseminating clone may have generated several variations. However, our study showed that one constellation of traits appeared most commonly: gelatinase, aggregation substance and esp (GEA). These factors are important because they have been implicated in cell aggregation and biofilm formation. Biofilm formation may promote the conjugation of plasmids harboring resistance and virulence genes, enhancing the probability of entry of new resistance genes into species. Curiously, the profile GEA was not exclusive to VREFS, it was the second most observed in VSEFS isolates from colonization and infection in hospitalized patients and also from rectal swabs of healthy volunteers. Such strains appear to represent the entry gateway to new resistance genes into E. faecalis and may contribute to the spreading of E. faecalis mainly in hospitals.

Medicación intraconducto frente al Enterococcus faecalis

“…Los factores de virulencia del E. faecalis están relacionados a varios elementos de la Pedraza-Maquera KI bacteria, tales como: la proteína de superficie extracelular del Enterococcus (Esp), la cual promueve la adhesión, colonización y evasión del sistema inmune; la presencia de un pilli que es importante en la producción del biofilm, la cual se ubica en la proteína Bps; la citolisina (Cyl) o hemolisina, le da propiedades B-Hemolíticas en humanos y es bactericida ante otras bacterias Gram positivas; la gelatinasa, (GelE) provee nutrientes a la bacteria degradando el tejido del huésped e interviene de alguna forma en la formación de biofilm (20); la sal biliar hidrolasa, le permite hidrolizar la bilis, este factor en conjunto con la producción de capsula y la formación de biofilm contribuyen con la patogénesis de este organismo (15); la hialuronidasa despolimeriza a la molécula de mucopolisacárido del tejido conectivo que le permite a la bacteria diseminarse; las determinantes de feromonas (Eep) modulan la respuesta inflamatoria in vivo; el antígeno A (EfaA) se asocia con la adherencia de la bacteria a células vivas o superficies inertes como la dentina; la proteína de superficie celular (Ace) le permite unirse al colágeno y jugaría un rol importante en la endocarditis (20); la sustancia de agregación (Agg), actúa en la unión de la bacteria al epitelio intestinal, células del epitelio renal, neutrófilos humanos y macrófagos. Esto es corroborado en un estudio reciente realizado por Melo et al en el 2019, que refiere que las heridas crónicas son difíciles de tratar porque son colonizadas por biopelìculas bacterianas que son altamente tolerantes a los antibióticos (15,(21)(22)(23).…”

Caracterização molecular de Enterococcus spp. resistentes à vancomicina em amostras clínicas, ambientes aquáticos e alimentos

“…A PCR para detecção dos genes de virulência foi realizado com base no mesmo utilizados por (CAMARGO et al, 2006;CAMARGO et al, 2008 (CAMARGO et al, 2006;CAMARGO et al, 2008).…”