Why is 35C is recommended for the CDS disc diffusion method rather than 37C?
A. The most profound effect is observed with Staphylococcus aureus and methicillin where incubation at temperatures above 37C may lead to a failure to detect MRSA. Because thermostats generally will allow 2C drift in temperature, we recommend setting the temperature at 35C to prevent it drifting above 37C. It was stressed in the original description of the CDS that the temperature of incubation must be “strictly controlled at 35-37C”. See page 34 of the CDS Monograph in the Archives section of the CDS web site for further information.
