Pharmacodynamic target attainment of seven antimicrobials against Gram-negative bacteria collected from China in 2003 and 2004

Using minimum inhibitory concentration (MIC) data derived from a Chinese national surveillance study and pharmacokinetic data collected in Chinese individuals, a 5000-subject Monte Carlo simulation was conducted to determine the cumulative fraction of response (CFR) for cefoperazone/sulbactam, cefotaxime, ceftazidime, ceftriaxone, ciprofloxacin, imipenem and meropenem against Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa collected during 2003 and 2004. The carbapenems had the highest CFRs against the Enterobacteriaceae (94.7-100%) and A. baumannii (66.0-86.3%). Ceftazidime, meropenem and cefoperazone/sulbactam obtained the greatest CFRs against P. aeruginosa (73.9-86.6% in Southern China and 64.8-82.1% in Northern China). All other cephalosporin and ciprofloxacin regimens achieved ≤50% CFR against all bacterial species. Meropenem 2 g every 8 h as a 3-h infusion displayed ca. 90% CFR against A. baumannii and P. aeruginosa. Pharmacodynamic analyses are useful for selecting optimal compounds and dosing regimens as initial empirical therapy against these organisms in China.