Mueller-Hinton agar Medium

The determination of MIC of antibiotics was performed by microtiter method. Antimicrobial agents were diluted by serial dilutions MPB in flat-bottomed plates, they were also added to the culture of Staphylococcus aureus, and were incubated for 24 hr at 34°C. The control was culture Staphylococcus aureus without antimicrobial agents. After that mixture sowed on solid nutrient medium Mueller-Hinton agar for calculation of amount of colony forming particles and MIC definitions. The MIC was considered to be the lowest concentration, which retards the growth of Staphylococcus aureus during the incubation period. 

Staphylococcus aureus without antimicrobial agents. After that mixture sowed on solid nutrient medium Mueller-Hinton agar for calculation of amount of colony forming particles and MIC definitions. MIC was considered to be the lowest concentration, which retards the growth of Staphylococcus aureus during the incubation period. 

Luria-Bertani (LB) agar, Mueller-Hinton (MH) agar or M9 agar (all from Difco Laboratories). The choice of the medium depends on the peptide used. If the peptide s activity is salt-sensitive, use of a low-salt minimal medium such as M9 is more appropriate. 

From the beginning, laboratory studies on the antibacterial properties of cefaclor pointed to an inherent chemical instability in solution and in neutral to alkaline bacteriological media. Test medium composition, pH, and inoculum density can significantly affect in vitro susceptibility assay results. For example, in both Mueller-Hinton broth and agar, chemical degradation of cefaclor is observed as a rapid loss of antimicrobial activity (50%) after 6 hr at 37°C (Preston, 1979). Special care is, therefore, recommended in the interpretation of in vitro test results. 

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