Deletion of essC abrogates essC transcription but does not affect GBS interaction with host cells, in vitro.

a) Expression of essC in CJB111+ pDC, CJB111ΔessC+ pDC, CJB111ΔessC + pDCessC strains by qRT-PCR. T7SS gene expression was normalized to housekeeping gene gyrA. Statistics reflect the repeated measures, one way ANOVA with Dunnett’s multiple comparisons test to CJB111ΔessC+pDC, p < 0.05, *. Data indicate the mean of three independent experiments and error bars represent standard error of the mean. The CJB111+ pDC, CJB111ΔessC+ pDC, CJB111ΔessC + pDCessC strains were further evaluated for b) adherence to (n = 3), c) invasion of (n = 3), or d) intracellular survival (12 hrs; n = 2) in human cerebral microvascular endothelial cells (hCMEC). Data represent percent CFU recovered of the initial inoculum and were performed in technical duplicates or triplicates.

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