Figure 3.

Resistance of the Mtb H37Rv Rv3484 deletion mutant against lysozyme. (a) Mtb wild type (H37Rv), Mtb H37RvΔRv3484, Mtb H37RvΔRv3484::Rv3484 as well as the mutant strain transformed with the empty vector pMV306 were exposed to lysozyme for 7 days and metabolic activity assessed using resazurin. Fluorescence was read at 590 nm in a microplate reader and the means and SEM of fluorescence intensities corrected by subtracting background fluorescence from wells containing dH₂O and resazurin alone were plotted. Two-way ANOVA and Bonferroni Post-hoc-test were used for statistical evaluation of the data. P-values ≤ 0.01 (**) and ≤0.0001 (****) were considered as significant. (b) Resistance of the Mtb H37Rv Rv3484 deletion mutant strain against meropenem/clavulanate. Mtb wild type (H37Rv), Mtb H37RvΔRv3484, Mtb H37RvΔRv3484::Rv3484 as well as the mutant strain transformed with the empty vector pMV306 were exposed to 0, 0.04, 0.08, 0.16, 0.32, 0.63, 1.25, 2.5, 5 µg/ml meropenem (each sample supplemented with 2.5 µg/ml clavulanate) and metabolic activity of the bacteria was assessed after 1 week by the addition of resazurin. Data are expressed as normalized fluorescence intensities after subtraction of background fluorescence emitted by wells containing resazurin in 7H9 medium. Comparisons were based on two-way ANOVA and the Bonferroni Post-hoc-test. P-values ≤ 0.01 (**) or ≤0.001 (***) were considered as significant. Means with error bars representing the SEM are shown.