Enterococcus faecium: caracterização molecular de amostras isoladas no período anterior e posterior a emergência da resistência à vancomicina no Estado do Rio de Janeiro

• Autor(a) principal: Faria, Adriana Rocha
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14440
• topic: Enterococcus faecium; MLVA; MLST; Tn546; CC17; MLVA; MLST; Tn1546; CC17; Enterococcus faecium; Resistência à vancomicina; Polimorfismo (Genética); CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA MOLECULAR E DE MICROORGANISMOS

In the last decades, vancomycin-resistant <i>Enterococcus</I> has emerged in the hospital setting worldwide. The emergence of vancomycin resistance in the State of Rio de Janeiro in 2000 was recorded in the species <i>Enterococcus faecalis</i>. Then, <i>Enterococcus faecium</i> has become prevalent. The aim of this study was to evaluate the genetic diversity of strains of <i>E. faecium</i> susceptible (VSEfm) and resistant (VREfm) to vancomycin, isolated in different hospitals located in Rio de Janeiro State, during the period from 1993 to 2008. The bacterial isolates were analyzed by pulsed-field gel electrophoresis (PFGE), after restriction with <i>Sma</i>I, multiple loci VNTR analysis (MLVA), and multilocus sequencing typing (MLST), besides the detection of phenotypic markers, such as resistance to ampicillin and ciprofloxacin, and by the genetic determinants of virulence that are linked to a globally dispersed clonal complex (CC17). The diversity of Tn<i>1546</i> (which harbours the <i>vanA</i> gene) was determined by amplification and restriction with <i>Cla</i>I. A prevalent clonal group was observed by PFGE related to isolates obtained mainly during the period 2004 to 2006, being spread by various health institutions of the state, indicating transmission inter-and intra-hospital. The assessment by MLVA identified two MTs prevalent among the VREfm isolates: MT12 that included most of the strains and was related to the major clonal group identified by PFGE; and the MT159 which showed an increased frequency in 2008. The analysis pointed out the MLST ST78 associated with the major clonal groups defined by PFGE, as well as the MT12. Typing correlation was also identified between ST412 clonal group and MT159. MLST showed that VREfm isolates obtained from the institutions in State of Rio de Janeiro, were related to CC17, including few representants of VSEfm. However, VREfm showed the main resistance markers and virulence characteristics of CC17, comparing with VSEfm, such as ampicillin and ciprofloxacin resistance, and the presence of the allele <i>purK</i>1 and <i>esp</i>. The identification of CC17 among VSEfm isolates to suggested that the presence of this adapted clones may facilitate the emergence of <i>vanA</i> determinant. Additionally, our data pointed to changes in the scenario of VREfm in Rio de Janeiro. The dominance of the prevalent clonal group (PFGE-X, MT12, ST78) may be replaced by the possible emergence of a new clonal group, which was characteristic of most recent samples (PFGE-XV, MT159, ST412). A prevalent restriction profile identical to the prototype Tn<i>1546</i> was observed, indicating that the spread of vancomycin resistance occurred also by horizontal transfer.