Muller hinton broth camhb

A. baumannii AB5075, an isolate from a patient at the Walter Reed Army Medical Center in USA, was examined in the present study as a type strain. A. baumannii AB5075 is resistant to ampicillin/sulbactum, amikacin, aztreonam, cefepime, levofloxacin and tobramycin [23 (link)]. MICs of polymyxin B and Rifampicin were 0.25 mg/L and 4 mg/L, respectively. Tryptone soy broth (TSB; Oxoid, Thebarton, Australia) with 20% glycerol was used for strain storage at − 80°C. AB5075 was streaked on nutrient agar before each experiment and sub-cultured in cation-adjusted Muller-Hinton broth (CAMHB; 20-25 mg/L Ca²⁺ and 10-12.5 mg/L Mg²⁺; Oxoid, Thebarton, Australia). Solution of polymyxin B sulfate (Sigma-Aldrich, Castle Hill, Australia) was freshly prepared in sterile Milli-Q water (Millipore, North Ryde, Australia) and filtered with 0.22 μm Millex GP filters (Millipore, Bedford, MA) before use. Rifampicin (Sigma-Aldrich, Castle Hill, Australia) was dissolved in dimethyl sulfoxide (DMSO, Sigma-Aldrich, Castle Hill, Australia).