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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2000-5-10
pubmed:abstractText
Haemophilus influenzae biogroup aegyptius (formerly H. aegyptius) is the etiologic agent of Brazilian purpuric fever (BPF). A surface-exposed epitope on the outer membrane protein P1 is present on most strains of H. influenzae biogroup aegyptius associated with BPF but is absent in almost all non-disease associated strains. The role of the outer membrane protein P1 in the pathogenesis of this disease was evaluated by utilizing an isogenic P1-deficient mutant. We compared the ability of the wild type and P1 isogenic mutant to grow under various conditions. The P1-deficient strain grew at a similar rate to the wild type in both complex and chemically defined medium. The P1-deficient mutant also had a similar growth rate to the wild type under anaerobic conditions. Anaerobic growth, however, resulted in up-regulation of the P1 protein in the wild type strain. Three assays were used to examine the pathophysiologic role of the P1 protein in BPF: 1) serum resistance; 2) sustained bacteremia in the infant rat model; and 3) the human microvascular endothelial cell (HMEC) cytotoxicity assay. Both the mutant and wild-type strains were resistant to killing in 95% normal human serum. The P1-deficient strain was also as virulent as the wild type in both the infant rat model of bacteremia and in the HMEC-1 tissue culture model. These results demonstrate that serum resistance, sustained bacteremia in the infant rat, and cytotoxicity of HMEC cells occur in the absence of P1. The P1 protein is not essential for the pathogenic potential identified by these assays. However, these results demonstrate that an anaerobic environment is a potent physiologic regulator of P1 protein expression. The impact of anaerobiosis on protein expression and pathogenesis will require further investigations.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0882-4010
pubmed:author
pubmed:copyrightInfo
Copyright 2000 Academic Press.
pubmed:issnType
Print
pubmed:volume
28
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
145-55
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Characterization of P1-deficient isogenic mutant of Haemophilus influenzae biogroup aegyptius associated with Brazilian purpuric fever.
pubmed:affiliation
Department of Microbiology, State University of New York at Buffalo, New York, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, Non-P.H.S.