Fig. 4.

Levels of lipoteichoic acids (LTAs) after treatment with several concentrations of SPT. Intracellular levels of a S. aureus ATCC 25922 (MSSA) and b S. aureus ST80 (MRSA) and c extracellular levels at MRSA. Bacteria were grown under biofilm conditions and lysed by bead beating. LTA levels in cell lysates or concentrated media were determined with semi-quantitative dot blot analysis, employing a monoclonal anti-LTA. All results are normalized against the total sample protein. Bars represent mean values ± SEM from at least three independent experiments. Brown-Forsythe tests and Welch ANOVA were employed for the statistical analysis. Notations for statistically significant differences between control (untreated) and treated samples: *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001. Inset in c: correlation analysis of LTA levels of MRSA with biofilm formation. Inhibition of MRSA biofilm strongly correlates inversely with the increase of extracellular LTA in a statistically significant manner