☰ Summary :
Ⅰ. Definition
In liquid medium, bacterial growth is visualized by a bacterial disorder.
MIC (minimum inhibitory concentration) : the lowest concentration of antibiotic inhibiting the visible growth of a given strain.
Ⅱ. Liquid medium
Mueller-Hinton (MH) broth, adjusted for divalent cations, is used in the liquid dilution method (micro-dilution) for non-demanding bacteria.
MH-F broth, MH broth supplemented with 5% lysed horse blood and 20 mg / L β-NAD, is used for Streptococcus spp., Including Streptococcus pneumoniae, Haemophilus spp., Moraxella catarrhalis, Listeria monocytogenes, Campylobacter spp. ., Pasteurella sp., Corynebacterium sp. and other slow growing bacteria.
Ⅲ. Operating mode
- A range of antibiotic (X) of decreasing concentrations is made by successive dilutions of 1/2 ratio from a stock solution of the antibiotic.
- A series is prepared with the same volume of the liquid culture medium.
- The same amount of germs are added to each tube (inoculum).
- The prepared tubes are incubated at 37 ° C for 18 hours.
- They are examined with the naked eye.
MIC in liquid medium
Conclusion : The higher the concentration required, the higher the MIC and the less sensitive the germ.