Antibiotic Resistance Profiling of Bacterial Strains

The minimum inhibitory concentration (MIC) was evaluated for ST541, ATCC29213, RC85, and RC85‐T strains. To confirm the role of MVs in interrupting antibiotic activity, several antimicrobials namely, ampicillin, cefotaxime, cefoperazone, colistin, gentamicin, and tetracycline were utilized. Eight β‐lactam antibiotics, i.e., ampicillin, amoxicillin, cefalexin, cefazolin, cefoperazone, cefotaxime, cloxacillin, and methicillin (Sigma‐Aldrich), and five other classes of antibiotics, i.e. colistin, gentamicin, nalidixic acid, streptomycin, and tetracycline (Sigma‐Aldrich) were selected to compare relative resistance levels of RC85‐T with that of RC85. The MIC was determined by broth‐dilution method in 96‐well plates (Andrews, 2001 (link); Kim et al., 2018 (link)). according to Clinical and Laboratory Standards Institute guidelines, except that cation‐adjusted Muller Hinton broth was substituted with LB. The MIC values were measured from three independent experiments.