A PHP Error was encountered

Severity: Warning

Message: Creating default object from empty value

Filename: models/publicacao_item.php

Line Number: 20

Characterization of a novel chaperone/usher fimbrial operon present... » Isaúde
  Pesquisar Publicações Científicas  
  Especialidade: carregando especialidades...  Carregando...
Nome da revista:   Volume:   Número:
BMC microbiology [electronic resource]
2012-04-21 03:30:35

Characterization of a novel chaperone/usher fimbrial operon present on KpGI-5, a methionine tRNA gene-associated genomic island in Klebsiella pneumoniae

Descrição: Background:Several strain-specific Klebsiella pneumoniae virulence determinants have been described, though these have almost exclusively been linked with hypervirulent liver abscess-associated strains. Through PCR interrogation of integration hotspots, chromosome walking, island-tagging and fosmid-based marker rescue we captured and sequenced KpGI-5, a novel genomic island integrated into the met56 tRNA gene of K. pneumoniae KR116, a bloodstream isolate from a patient with pneumonia and neutropenic sepsis.Results:The 14.0 kb KpGI-5 island exhibited a genome-anomalous G+C content, possessed near-perfect 46 bp direct repeats, encoded a gamma1 chaperone/usher fimbrial cluster (fim2) and harboured seven other predicted genes of unknown function. Transcriptional analysis demonstrated expression of three fim2 genes, and suggested that the fim2A-fim2K cluster comprised an operon. As fimbrial systems are frequently implicated in pathogenesis, we examined the role of fim2 by analysing KR2107, a streptomycin-resistant derivative of KR116, and three isogenic mutants (Deltafim, Deltafim2 and DeltafimDeltafim2) using biofilm assays, human cell adhesion assays and pair-wise competition-based murine models of intestinal colonization, lung infection and ascending urinary tract infection. Although no statistically significant role for fim2 was demonstrable, liver and kidney CFU counts for lung and urinary tract infection models, respectively, hinted at an ordered gradation of virulence: KR2107 (most virulent), KR2107[increment]fim2, KR2107[increment]fim and KR2107[increment]fim[increment]fim2 (least virulent). Thus, despite lack of statistical evidence there was a suggestion that fim and fim2 contribute additively to virulence in these murine infection models. However, further studies would be necessary to substantiate this hypothesis.Conclusion:Although fim2 was present in 13% of Klebsiella spp. strains investigated, no obvious in vitro or in vivo role for the locus was identified, although there were subtle hints of involvement in urovirulence and bacterial dissemination from the respiratory tract. Based on our findings and on parallels with other fimbrial systems, we propose that fim2 has the potential to contribute beneficially to pathogenesis and/or environmental persistence of Klebsiella strains, at least under specific yet-to-be identified conditions.

Identificador: doi:10.1186/1471-2180-12-59
Volume: 0
Página: 5 a


Mais informações

  • Twitter iSaúde
publicidade
Jornal Informe Saúde

Indique o portal
Fechar [X]
  • Você está indicando a notícia: http://www.isaude.net
  • Para que seu amigo(a) receba esta indicação preencha os dados abaixo:

RSS notícias do portal  iSaúde.net
Receba o newsletter do portal  iSaúde.net
Indique o portal iSaúde.net
Notícias do  iSaúde.net em seu blog ou site.
Receba notícias com assunto de seu interesse.
© 2000-2011 www.isaude.net Todos os direitos reservados.