Survey of MRSA infection in Ibaraki-ken--Ibaraki Association for infectious diseases

This study which was undertaken at several major hospitals in Ibaraki-ken revealed that, 1) the proportion of Staphylococcus aureus in all the isolates ranged from 5% to 17% and the prevalence of MRSA in isolates of Staphylococcus aureus varied from 51% to 82% depending upon each individual hospital. 2) the clinical response to FOM and CMZ combination therapy was 88.9% and, to FOM and CZON was 57.1% showing no statistical differences between the two regimens. 3) in vitro analyses assessed by the FIC index of 251 isolates revealed that FOM had an additive or synergistic effect with CMZ in 53.8%, with CZON in 66.9%, with minocycline (MINO) in 43.8%, with cefamandole (CMD) in 61.8%, with cefazolin (CEZ) in 62.9% and with imipenem/cliastatin sodium (IPM/CS) in 68.9% at all isolates. 4) the cumulative curve of susceptibility to single CMZ and the combination of CMZ and FOM revealed that the blood levels of CMZ at 3 hours after intravenous administration covered 57% of isolates when used alone and 82% of isolates when in combination with FOM. The blood levels of CZON at 3 hours covered 5% of isolates when used alone and 41% when in combination with FOM. The extent of the therapeutic effect increased from 6% to 42% by CMD, from 12% to 54% by CEZ, from 20% to 58% by IPM/CS and from 78% to 84% by MINO. The combination of CMZ and FOM was found to be the most effective for enhanced effects on MRSA in vitro.