Transcriptome analyses extend understanding of Streptococcus pyogenes regulatory mechanisms and behavior toward immunomodulatory substances.

The recent genome sequencing of several Streptococcus pyogenes serotype strains allowed the design of corresponding DNA microarrays and their usage for specific transcriptome analyses. In the present study, we employed transcriptomics together with functional tests to investigate the impact of the CiaH sensor gene of the CiaRH two-component regulator on gene expression and virulence traits of serotype M49 S. pyogenes strains CS101 and 591. In parallel, we studied the effects of the immunostimulatory substance Luivac on the serotype M49 S. pyogenes transcriptome and several biological features of serotype M1, M2, M3, M6, M18, and M49 S. pyogenes strains. Overall, the transcriptome analyses allowed a swift identification of differences in transcript abundance apparently associated with the observed strain-specific changes in matrix protein binding, eukaryotic cell interactions, or biofilm formation of the ciaH mutants and of wild-type strains exposed to a commercially available substance used for preventing upper respiratory tract infections.