Modification of the Sceptor system for rapid detection of methicillin-resistant staphylococci.

The 24-h Sceptor MIC system (Johnston Laboratories, Inc., Towson, Md.) was modified to allow rapid (6 h) detection of methicillin-resistant staphylococci. For 105 methicillin-resistant staphylococci tested, 90% of the results obtained by the 6-h method agreed with those obtained by disk agar diffusion. In comparison, 88 and 93% of the results obtained by the AutoMicrobic system (Vitek Systems, Inc., Hazelwood, Mo.) and the 24-h conventional Sceptor system, respectively, agreed with disk agar diffusion results. No false-resistant results were observed with 52 methicillin-susceptible staphylococci tested by any of the three methods.