[Method of determining the sensitivity of Staphylococcus aureus to methicillin]

The effect of the incubation temperature, i.e. 37 and 30 degrees and the effect of addition of 5 per cent of sodium chloride to the nutrient medium was studied with respect to the results of sensitivity determination of staphylococci to methicillin by 3 methods, such as serial dilutions in liquid and solid media and replica method applied to separate colonies. With the use of all 3 methods incubation of the samples at a temperature of 30 degrees increased the rate of staphylococcal cultures resistant to methicillin. Addition of sodium chloride to the solid nutrient medium increased the level of detecting methicillin resistant cultures in the samples incubated at a temperature of 37 degrees and decreased it in the samples incubated at 30 degrees.