Abstract:
:Small-colony variants (SCVs) are slow-growing variants of human bacterial pathogens. They are associated with chronic persistent infections, and their biochemical identification and antimicrobial treatment are impaired by altered metabolic properties. To contribute to the understanding of SCV-mediated infections, we analyzed a clinical SCV isolate derived from a chronic prosthetic hip infection. A sequence analysis of housekeeping genes identified an Enterobacter hormaechei-like organism. The SCV phenotype, with growth as microcolonies, was caused by a block within the heme biosynthesis pathway through deletion of the hemB locus, as shown by hybridization and complementation experiments. At a low frequency, large-colony variants (LCVs) arose that were dependent on exogenous hemin. To investigate this phenomenon, we cloned and sequenced the 5.8-kb hemin uptake system, denoted ehu. Gene expression analysis indicated regulation of this locus in wild-type bacteria by the global iron regulator Fur. Inactivation of Fur in LCVs caused the derepression of ehu expression and facilitated bacterial growth. Genetic alterations of the fur locus in LCVs were identified as insertions of IS1A elements and point mutations. In contrast, SCVs could utilize exogenous hemin only in the absence of iron. Thus, we provide the first molecular characterization of the growth properties of a clinical SCV isolate, which may help to improve the diagnostic and therapeutic management of patients with chronic persistent infections.
journal_name
Infect Immunjournal_title
Infection and immunityauthors
Roggenkamp A,Hoffmann H,Hornef MWdoi
10.1128/iai.72.4.2254-2262.2004keywords:
subject
Has Abstractpub_date
2004-04-01 00:00:00pages
2254-62issue
4eissn
0019-9567issn
1098-5522journal_volume
72pub_type
杂志文章abstract::Recruitment of neutrophils to lung tissue and airspaces is a hallmark of inflammatory events following inhalation of endotoxins. We studied the role of different lymphocyte subsets in this inflammation, which is assumed to primarily involve the innate immune system. Inhalation of aerosolized Escherichia coli lipopolys...
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pub_type: 临床试验,杂志文章,随机对照试验
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doi:10.1128/IAI.00674-09
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journal_title:Infection and immunity
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更新日期:2001-07-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.72.8.4868-4873.2004
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pub_type: 杂志文章
doi:10.1128/iai.71.1.68-74.2003
更新日期:2003-01-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.01199-12
更新日期:2013-04-01 00:00:00
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pub_type: 杂志文章
doi:10.1128/IAI.72.6.3097-3105.2004
更新日期:2004-06-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.31.1.199-207.1981
更新日期:1981-01-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00622-10
更新日期:2010-10-01 00:00:00
abstract::Immunity to pneumococcal colonization in mice by exposure to live or killed pneumococci has been shown to be antibody independent but dependent on CD4+ T cells. Here we show that intranasal immunization with pneumococcal proteins (pneumococcal surface protein C, adhesin A, and a pneumolysoid) can elicit a similar mech...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00773-07
更新日期:2007-11-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.10.6.1292-1295.1974
更新日期:1974-12-01 00:00:00
abstract::A receptor specific for lipoglycans from Acholeplasma axanthum and Acholeplasma granularum was isolated from sheep erythrocyte stroma by extraction with n-pentanol and permeation chromatography. The purified receptor appeared as one band on sodium dodecyl sulfate-polyacrylamide gels and stained with Coomassie blue, pe...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.38.3.1078-1087.1982
更新日期:1982-12-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.57.12.3894-3900.1989
更新日期:1989-12-01 00:00:00
abstract::Light and electron microscopy with histochemical staining were used to estimate exopolysaccharide production by strains of viridans streptococci recovered from patients with endocarditis. Six strains were selected for study because they represented a wide range of in vitro polysaccharide production. By light microscop...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.43.1.359-367.1984
更新日期:1984-01-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.01311-15
更新日期:2016-04-22 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.6.1.83-91.1972
更新日期:1972-07-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.13.3.982-986.1976
更新日期:1976-03-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.23.2.253-259.1979
更新日期:1979-02-01 00:00:00
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journal_title:Infection and immunity
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更新日期:1975-05-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.62.11.5161-5163.1994
更新日期:1994-11-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.7.6.898-904.1973
更新日期:1973-06-01 00:00:00
abstract::Since melanin is considered a virulence factor in Cryptococcus neoformans, its suppression at 37 degrees C has been perplexing. We now show an opposite thermal regulation of superoxide dismutase (SOD), consistent with a compensatory mechanism. Moreover, we demonstrate normal SOD and catalase levels in albino, oxygen-s...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.62.9.4085-4086.1994
更新日期:1994-09-01 00:00:00
abstract::Mice infected with various strains of Salmonella enteritidis and S. typhimurium were found to be more sensitive to the cell wall lipopolysaccharide (LPS) extracted from certain strains of Salmonella than noninfected mice. This hypersensitivity was induced by those smooth or rough strains which possessed a polysacchari...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.4.5.519-524.1971
更新日期:1971-11-01 00:00:00
abstract::Gamma interferon (IFN-gamma), a pleiotropic cytokine, is now known to be produced by macrophages as well as by NK cells, gammadelta cells, and activated T cells. The autocrine biological functions of IFN-gamma on the macrophage include the upregulation of major histocompatibility complex MHC class II and the activatio...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.69.6.3605-3610.2001
更新日期:2001-06-01 00:00:00
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pub_type: 杂志文章
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更新日期:2015-10-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.69.5.3021-3030.2001
更新日期:2001-05-01 00:00:00
abstract::The capacity of Candida albicans to switch reversibly between the white phenotype and the opaque phenotype is required for the fungus to mate. It also influences virulence during hematogenously disseminated candidiasis. We investigated the roles of the mating type loci (MTL) and white-opaque switching in the capacity ...
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pub_type: 杂志文章
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更新日期:2018-05-22 00:00:00
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pub_type: 杂志文章
doi:10.1128/IAI.00372-10
更新日期:2010-07-01 00:00:00