Figure 4From: Azithromycin effectiveness against intracellular infections of FrancisellaMIC determination of Az for F. novicida transposon LPS and RND efflux mutants and F. tularensis Schu S4 RND efflux mutants. A) The MIC of Az for LPS O-antigen F. novicida transposon mutants was generally higher than the wild-type (circle) MIC of 0.78 μg/ml. MICs for LPS O-antigen mutants were 12.5 μg/ml for wbtA (diamond), 25.0 μg/ml for wbtE (down triangle), 3.12 μg/ml for wbtQ (square), and 12.5 μg/ml for wbtN (triangle), with an EC50 for all LPS O-antigen mutants greater than 0.50 μg/ml (p-value < 0.005). B) MICs for F. novicida transposon-insertion RND efflux mutant varied: dsbB (down triangle) was closer to the wild-type (closed circle) at 1.56 μg/ml (p-value 0.400). ftlC, tolC, acrA, and acrB have greater MIC with 25 μg/ml for ftlC (square) and 50 μg/ml for tolC (up triangle), acrA (diamond), and acrB (open circle), with EC50 greater than 12 μg/ml (p-value < 0.005). C) The MICs of Az for F. tularensis Schu S4 (square) and deletion RND efflux mutants. F. tularensis Schu S4 (square) has an MIC of 0.78 μg/ml, ΔacrB (circle) of 1.56 μg/ml, and ΔacrA (diamond) of 3.13 μg/ml. F. tularensis Schu S4 and mutants all have EC50 less than 0.15 μg/ml (p-value < 0.1 for ΔacrA and ΔacrB compared to wild-type).Back to article page