RESUMO
Background: The use of antimicrobials and myeloablative chemotherapy regimens has promoted multiresistant microorganisms to emerge as nosocomial pathogens, such as vancomycin-resistant Enterococcus faecium (VREfm). We described a polyclonal outbreak of bloodstream infection caused by Efm in a hemato-oncological ward in Mexico. Our aim was to describe the clonal complex (CC) of the Efm strains isolated in the outbreak in comparison with commensal and environmental isolates. Methodology: Sixty Efm clinical, environmental, and commensal strains were included. We constructed a cladogram and a phylogenetic tree using Vitek and Multilocus sequence typing data, respectively. Results: We reported 20 new sequence types (ST), among which 17/43 clinical isolates belonged to CC17. The predominant ST in the clinical strains were ST757, ST1304, ST412, and ST770. Neither environmental nor commensal isolates belonged to CC17. The phylogeny of our collection shows that the majority of the clinical isolates were different from the environmental and commensal isolates, and only a small group of clinical isolates was closely related with environmental and commensal isolates. The cladogram revealed a similar segregation to that of the phylogeny. Conclusions: We found a high diversity among clinical, environmental, and commensal strains in a group of samples in a single hospital. Highest diversity was found between commensal and environmental isolates.
Assuntos
Bacteriemia/epidemiologia , Infecção Hospitalar/epidemiologia , Enterococcus faecium/genética , Infecções por Bactérias Gram-Positivas/epidemiologia , Filogenia , Enterococos Resistentes à Vancomicina/genética , Adulto , Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Bacteriemia/microbiologia , Bacteriemia/patologia , Técnicas de Tipagem Bacteriana , Células Clonais , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Infecção Hospitalar/patologia , Enterococcus faecium/classificação , Enterococcus faecium/efeitos dos fármacos , Enterococcus faecium/isolamento & purificação , Feminino , Variação Genética , Genótipo , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/patologia , Neoplasias Hematológicas/microbiologia , Neoplasias Hematológicas/patologia , Humanos , Masculino , México/epidemiologia , Tipagem de Sequências Multilocus , Fenótipo , Simbiose/fisiologia , Centros de Atenção Terciária , Enterococos Resistentes à Vancomicina/classificação , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/isolamento & purificaçãoRESUMO
BACKGROUND: Enterococcus faecium causes bloodstream infection (BSI) in patients with hematologic malignancies (HMs). We studied the clinical features and outcomes of patients with HM with vancomycin-sensitive E faecium (VSE) and vancomycin-resistant E faecium (VRE) BSI and determined the genetic relatedness of isolates and circumstances associated with the upsurge of E faecium BSI. METHODS: Case-control study of patients with HM and E faecium-positive blood culture from January 2008-December 2012; cases were patients with VRE and controls were VSE isolates. The strains were tested for Van genes by polymerase chain reaction amplification and we performed pulsed-field gel electrophoresis to determine genetic relatedness. RESULTS: Fifty-eight episodes of E faecium BSI occurred: 35 sensitive and 23 resistant to vancomycin. Mortality was 46% and 57%, attributable 17% and 40%, respectively. Early stage HM was associated with VSE (P = .044), whereas an episode of BSI within the 3 months before the event (P = .039), prophylactic antibiotics (P = .013), and vancomycin therapy during the previous 3 months (P = .001) was associated with VRE. The VanA gene was identified in 97% of isolates studied. E faecium isolates were not clonal. CONCLUSIONS: E faecium BSI was associated with high mortality. This outbreak of VRE was not clonal; it was associated with antibiotic-use pressure and highly myelosuppressive chemotherapy.