Project description:Better understanding of S. aureus throat colonization in the presence of other competing/coexisting microbes may provide insight into S. aureus adaptation to the human throat and recurrence of infection. In this work, we explore the responses triggered by the encounter between two common throat bacteria, S. aureus and S. anginosus, in the presence of human tonsillar epithelial cells. We performed an in vitro coculture experiment followed by RNA sequencing. A total of 332 and 279 significant DEGs with p-value < 0.05 and Log2 fold change > |2| were identified after 1 h and 3 h of post-infection, respectively. Our study identified several transcripts in S. aureus that might be important when facing a potential competitor during throat colonization. These transcripts may be useful in the development of treatments against S. aureus throat colonization and could be further investigated to better understand their roles in the immune response.
Project description:This study represents the first in vivo genome wide analysis of gene epxression of Group A Streptococcus (GAS) in humans with pharyngitis. The micorarray used is a custom microarray that relies on an electrochemical reaction as the measured signal rather than flourescence. Distinct clusters of gene expression were discovered and analyzed. A functional analysis examining differences and similarities between the clusters was performed. Samples were taken from pediatric patients who had received a throat swab as part of their clinical care for evaluating pharyngitis. Eleven samples that were culture postive for GAS were used along with 3 samples from subjects who were GAS culture negative. The microarray was a composite comprised of 12,000 probes, representing 2724 GAS open reading frames belonging to serotypes M1, M3, M4, M12, and M28. There were 1671 probe sets that were homologous for the M1 serotype and represented over 95% of the total predicted coding region. Probe sets were 30-40mers in length and were selected using a Combimatrix probe selection algorithm taking into account gene (>90% BLAST score) and serotype specificity, Tm, hairpins and GC content. In addition, 70 Combimatrix built in probes were used as negative controls for background subtraction.
Project description:Nasal colonization is well described; however, we have limited knowledge about S. aureus throat colonization. The main objective of this project was to explore differentially expressed genes (DEGs) in S. aureus throat isolate TR145 exposed for 1 or 3 hours (h) to human tonsil epithelial cells (HTEpiC) by using RNA sequencing (RNA-seq) and pathway analysis. We have shown the suitability of using HTEpiC as an in vitro model for investigating key determinants in S. aureus during co-incubation with the HTEpiC cells. Among the DEGs were genes encoding proteins involved in adhesion and immune evasion, as well as iron acquisition and transport. As their expression is induced upon meeting with the HTEpiC, they might be explored further for future targets for intervention to prevent either colonization or infection in the throat region.
