Vitamin E antibiotic adjuvant effect depends on the BcnA protein. Vitamin E antibiotic adjuvant effect depends on the BcnA protein. (A) MIC of norfloxacin alone or in combination with 0.7 mM TPGS against Burkholderia strains, determined by broth microdilution in cation-adjusted Mueller-Hinton broth (MHB) at 24 h. Data points are from 4 independent experiments, each done in duplicate (n = 8). (B) MIC of ceftazidime alone or combined with TPGS against Burkholderia strains in MHB at 24 h (n = 4, from 2 independent experiments). (C) MIC of norfloxacin alone or mixed with 1.4 mM TPGS against ΔbcnA mutants carrying pDA17 and ΔbcnA mutants harboring pDA17 bcnA, determined by broth dilution methods in MHB at 24 h (n = 4, from 2 independent experiments). (D) MIC of ceftazidime alone or mixed with 1.4 mM TPGS against ΔbcnA mutants carrying pDA17 and ΔbcnA mutants harboring pDA17 bcnA at 24 h (n = 4, from 2 independent experiments). Results are shown as the mean MIC ± SEM, and P values were calculated by the paired t test. Marwa M. Naguib, and Miguel A. Valvano mSphere 2018; doi:10.1128/mSphere.00564-18