Caracterização fenotípica e molecular de fatores de virulência de Enterococcus faecium de origem hospitalar

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Enterococci are Gram-positive cocci commonly found in the gastrointestinal tract of humans and animals as well as in soil, water and food. However, they are now among the leading causes of nosocomial infections. Vancomycin-resistant enterococci (VRE) were first identified in the late 1980s in a few European countries. The genes that encode the six types of acquired vancomycin resistance are typically associated with mobile genetic elements. Several virulence factors were described for enterococci, but little is known about the virulence of Enterococcus faecium. In the present study, forty E. faecium vancomycin-resistant (VREF) isolated from different sources at the University Hospital of Londrina, Paraná were examined for the putative virulence factors encoded by cylA, efaA, gelE and esp genes and their resistance genotype. These isolates were recovered from hospitalized patients (18 colonizers and 12 enterococci-infected patients) and their environment vicinity (n = 10). Resistance to vancomycin was common to all isolates and they harbored the vanA gene. Antimicrobial susceptibility profile was analyzed by automated microdilution method. The occurrence of a high frequency of multiple antimicrobial-resistance was detected among these isolates and this phenotype was independent of the origin from they were recovered. The virulence factors were investigated by molecular and phenotypic methods. The prevalence of the virulence genes was as follows: esp (87.5%), efaA (82.5%), gelE (70%) and cylA (65%). All isolates harbored at least one putative virulence marker and the presence of four genes was observed in 32.5% isolates. Only the presence of gelE gene was significantly higher in colonizers and infection-isolates compared to environmental isolates. In addition, the presence of efaA gene was associated with the presence of the esp gene, independent of the origins of the isolates. A positive association between the presence of cylA gene and hemolytic activity on sheep blood agar assay was observed. In contrast, no association was found either for gelE gene and gelatinase production on agar plate assay or for esp gene and biofilm formation on polystyrene surface. These results showed the potential virulence of nosocomial multiple-resistant E. faecium isolated from different sources and the knowledge about the role of them on its pathogenesis can contribute to develop new strategies for enterococci infection combat.

ASSUNTO(S)

enterococcus faecium infecções enterocócicas bactérias gram-positivas virulência (microbiologia) gram-positive bacteria virulence (microbiology)

ACESSO AO ARTIGO

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