Minimum Bactericidal Concentration Determination

The minimum bactericidal concentration (MBC) of NCL195 alone or in combination with EDTA, PMBN, or PMB was determined against both Gram-positive and Gram-negative bacteria. Briefly, 10-μL aliquots from each duplicate well from the MIC assays (starting from the MIC for each compound) were inoculated onto a sheep blood agar (SBA) plate and incubated at 37°C. Plates were examined at 24 and 48 h and the MBC was recorded as the lowest concentration of each test compound at which a 99.95% colony count reduction was observed on the plate (Clinical and Laboratory Standards Institute [CLSI], 2017).