In vivo synergistic effect between cefpirom and vancomycin against severe infections with methicillin-resistant Staphylococcus aureus in critically ill patients

Background - The aim of this study was to evaluate in vivo the improvement of bactericidal kinetic of vancomycin associated with cefpirom against MRSA infection in critically ill patients. Methods - The prospective cross-over study was carried out in 20 patients with severe pneumonia or bacteriemia. There were randomized to receive vancomycin 2 g per day (Group 1, n = 10) or vancomycin with cefpirom 2 g x 2 (Group 2, n = 10). Clinical recovery, bacteriologic parameters (bactericidal kinetic and bactericidal power in vivo at the peak and the valley), duration of ventilation and stay in ICU were comparatively explorated in both groups. Results - Clinical outcome did not significantly differ between Group 1 and 2. Bactericidal kinetic was better in the Group 2 (40% vs 60% after 6 hours to the dilution for 1/8(e)) but the difference was not significant. However, bactericidal power in sera was also better in the Group 2 with more bactericidal dilution at 1/16(e) (68% vs 88.8%: NS) and overall at 1/32(e) (10.5% vs 50%: p < 0.05) and CRP an inflammatory marker, was significantly lower in the Group 2 than in the Group 1 (119,5 +/- 24 mg/l vs 198.6 +/- 78 mg/l: p < 0. 05) on the third day. (C) 2002 Editions scientifiques et medicales Elsevier SAS.