Moenomycin

Mtb was grown to mid-log phase and diluted to an OD of 0.03 in 7H9 medium. Bacteria were then exposed to 1.5-fold serial dilution of antimicrobial compounds. Optical density was recorded after 14 days and normalized to the corresponding strains without drug treatment. Minimum inhibitory concentration is defined as the lowest concentration of a drug at which bacterial growth was inhibited at least 90%, as compared to the control containing no antimicrobial compounds. Ampicillin, auranofin, D-cycloserine, ebselen, ethambutol, faropenem, hydroxyurea, isoniazid, kanamycin, levofloxacin, meropenem, mitomycin C, moxifloxacin, piperacillin, rifampicin, streptomycin and vancomycin were purchased from Sigma Aldrich, St. Louis, MO. Moenomycin was from Santa Cruz Biotechnology. Bedaquilline was received as a gift from C. Barry.

S. aureus strains LAC* (ANG1575), LAC* ∆957 (ANG4290), LAC* ∆957 S2 (ANG4382) and LAC* ∆957 S4 (ANG4384) were grown overnight (18 hr) in 5 ml of LB. The next day, the cells were diluted to an OD₆₀₀ of 0.01 in LB, grown until mid‐exponential phase (OD₆₀₀ 0.4–0.6) and normalized to an OD₆₀₀ of 0.1. The cells were 10‐fold serially diluted and 5 µl of each dilution spotted onto LB agar containing 0.5 M NaCl with either 0.02 µg/ml of moenomycin (mix of moenomycin A, A12, C1, C3 and C4, Santa Cruz Biotechnology) or no moenomycin. Plates were incubated at 37°C overnight (18–22 hr) and photographed. The experiment was done with 3 biological replicates (n = 3) and one representative result is shown.