ArticleInternational journal of pediatric otorhinolaryngology2009
Interaction of phase variation, host and pressure/gas composition: pneumococcal gene expression of PsaA, SpxB, Ply and LytA in simulated middle ear environments.
Article in International journal of pediatric otorhinolaryngology, 2009. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 10 papers.
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Who cites it
10 citing papers in PubMed.
- The middle ear-nasopharyngeal microbiome axis associated with obstructive Eustachian tube dysfunction in chronic otitis media.mSystems · 2026Article
- Structure, Function, and Regulation of LytA: TheMicroorganisms · 2025Review
- Subversion of host immune responses by otopathogens during otitis media.Journal of leukocyte biology · 2019Review
- Mitochondrial DNA Leakage Caused byFrontiers in microbiology · 2019Article
- Insights into structure and activity of natural compound inhibitors of pneumolysin.Scientific reports · 2017Article
- Adhesion and invasion of Streptococcus pneumoniae to primary and secondary respiratory epithelial cells.Molecular medicine reports · 2017Article
- Co-Transcriptomes of Initial Interactions In Vitro between Streptococcus Pneumoniae and Human Pleural Mesothelial Cells.PloS one · 2015Article
- Pyruvate oxidase influences the sugar utilization pattern and capsule production in Streptococcus pneumoniae.PloS one · 2013Article
- Streptococcus pneumoniae isolates from middle ear fluid and nasopharynx of children with acute otitis media exhibit phase variation.Journal of clinical microbiology · 2011Article
- Immune responses to recombinant pneumococcal PsaA antigen delivered by a live attenuated Salmonella vaccine.Infection and immunity · 2010Article
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Authors and funding
5 authors.
Funding
Abstract
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 24h 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 ∼ 10(7)CFU/ml of either T or O variants of S. pneumoniae (6A) for 3h. 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 3h 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 3h 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.
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