کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4115185 1606065 2009 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Interaction of phase variation, host and pressure/gas composition: Pneumococcal gene expression of PsaA, SpxB, Ply and LytA in simulated middle ear environments
موضوعات مرتبط
علوم پزشکی و سلامت پزشکی و دندانپزشکی بیماری های گوش و جراحی پلاستیک صورت
پیش نمایش صفحه اول مقاله
Interaction of phase variation, host and pressure/gas composition: Pneumococcal gene expression of PsaA, SpxB, Ply and LytA in simulated middle ear environments
چکیده انگلیسی

ObjectiveStreptococcus pneumoniae, a leading cause of otitis media (OM), undergoes spontaneous intra-strain variations in colony morphology. Transparent (T) variants are more efficient in colonizing the nasopharynx while opaque (O) variants exhibit greater virulence during systemic infections. This study was intended to delineate the underlying molecular mechanisms by which the predominant S. pneumoniae variant efficiently infects the middle ear (ME) mucosa.MethodsHuman ME epithelial cells were preconditioned for 24 h under one of the three gas/pressure conditions designed to simulate those for (1) normal ME (NME), (2) ME with Eustachian tube obstruction (ETO) and (3) ME with tympanostomy tube placement (TT), and then were incubated with ∼107 CFU/ml of either T or O variants of S. pneumoniae (6A) for 3 h. Relative expression levels of genes encoding virulence factors, PsaA (surface adhesion), SpxB (pyruvate oxidase), Ply (pneumolysin), and LytA (autolysin) were assessed separately in epithelium-attached and supernatant bacteria 3 h post infection using real-time PCR.ResultsBasal levels of the virulence molecules in inocula were comparable between two variants. However, relative expression levels of the gene transcripts were significantly induced in epithelium-attached T variants 3 h after infection. Comparing with NME and TT conditions, ETO environment produced the largest effect on the differential expression of the virulence genes in the infected ME epithelial cells between T (induced) and O (suppressed) phenotypic pneumococci.ConclusionsT variant is a predominant phenotype responsible for the pathogenesis of pneumococcal OM.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Pediatric Otorhinolaryngology - Volume 73, Issue 10, October 2009, Pages 1417–1422
نویسندگان
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