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The haem-haemopexin utilization gene cluster (hxuCBA) as a virulence factor of Haemophilus influenzae.
Morton, Daniel J; Seale, Thomas W; Madore, Larissa L; VanWagoner, Timothy M; Whitby, Paul W; Stull, Terrence L.
Afiliação
  • Morton DJ; Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
  • Seale TW; Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
  • Madore LL; Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
  • VanWagoner TM; Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
  • Whitby PW; Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
  • Stull TL; Department of Microbiology/Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
Microbiology (Reading) ; 153(Pt 1): 215-224, 2007 Jan.
Article em En | MEDLINE | ID: mdl-17185550
ABSTRACT
Haemophilus influenzae has an absolute growth requirement for a porphyrin source, which can be supplied in vitro by haem, haemoglobin, or the haemoglobin-haptoglobin, haem-haemopexin and haem-albumin complexes. Utilization of the haem-haemopexin complex is known to be mediated by the products of the hxuCBA gene cluster. It was demonstrated that hxuC, but not hxuA or hxuB, is also essential for the utilization of haem from haem-albumin complexes. Mutants of the type b strain E1a lacking genes in the hxuCBA gene cluster were examined for their ability to cause bacteraemia in rat models of invasive disease. In 5-day-old rats, mutants in the hxuCBA genes yielded a significantly reduced bacteraemic titre compared to the wild-type strain. In addition, 5-day-old rats infected with the hxuCBA mutant strains exhibited significantly improved survival rates compared to those infected with the wild-type strain. Mutations in the haemoglobin/haemoglobin-haptoglobin-binding protein genes (hgps), either alone or in combination with the hxuCBA mutations, had no impact on virulence in 5-day-old rats. In 30-day-old rats infected with either the hxuCBA mutants or the wild-type strains, there was no significant difference in the ability to establish bacteraemia although bacterial titres were lower in rats infected with the hxuCBA mutants than in those infected with the wild-type strain. These age-related differences in the impact of mutations in the hxuCBA gene cluster may be related to changes in levels of host haem-binding proteins during development of the rat.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Proteínas de Bactérias / Hemopexina / Haemophilus influenzae / Fatores de Virulência / Infecções por Haemophilus / Heme Tipo de estudo: Prognostic_studies Limite: Animals Idioma: En Revista: Microbiology (Reading) Assunto da revista: MICROBIOLOGIA Ano de publicação: 2007 Tipo de documento: Article País de afiliação: Estados Unidos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Proteínas de Bactérias / Hemopexina / Haemophilus influenzae / Fatores de Virulência / Infecções por Haemophilus / Heme Tipo de estudo: Prognostic_studies Limite: Animals Idioma: En Revista: Microbiology (Reading) Assunto da revista: MICROBIOLOGIA Ano de publicação: 2007 Tipo de documento: Article País de afiliação: Estados Unidos