I am working on detecting antibiotic susceptibility of klebsiella pneumoniae with different discs. My question is which solution must be use to determine 0.5 Mcfarland? 0.9% NaCl or Müller Hinton Broth?
you should use % 0.9 NACL solution, MHB is unnessesary since you're going to sow the suspension on an Agar Plate as soon as you have misured it, also MHB is "more torbid" by itself (becaused colored in light brown) and would affect the McFarland determination.