P2088 Variations and trends in the activity of doripenem and other broad-spectrum agents against leading bacterial pathogens: results from a European Surveillance Program (2003–2006)

Abstract

Objectives: To summarize the results of a European-focused surveillance program comparing activity of doripenem and other agents tested against leading contemporary pathogens. Doripenem is a broad-spectrum investigational parenteral carbapenem in late-stage clinical development that displays enhanced activity against Pseudomonas aeruginosa compared with other marketed carbapenems. As we continue to evaluate doripenem, regional data assessing resistance patterns of targeted pathogens are needed. Methods: Non-duplicate bacterial isolates (27,689; bloodstream, 54.5%; respiratory tract, 21.6%; skin and skin structure, 8.3%; others, 15.6%) were collected from 24 medical centers in Europe during 2003-2006. Identifications were confirmed and all isolates were susceptibility tested using CLSI broth microdilution methods and interpretive criteria. Results: At MIC values of 0.25 mg/L for Streptococcus pneumoniae, 0.5 mg/L for b-haemolytic streptococci and Haemophilus influenzae, and 4 mg/L for all others (equivalent to peer agents), doripenem inhibited 95.7% of the tabulated pathogens recovered from all sources. Doripenem was broadly active against staphylococci, streptococci, and H. influenzae, and at least 2-fold more potent against P. aeruginosa than either meropenem or imipenem (MIC 90 /% ≤4 mg/L: 8/85, >8/81, >8/76, respectively). Only polymyxin B (>99% susceptibility) and amikacin (89%) provided greater P. aeruginosa coverage than doripenem. While ESBL phenotype rates varied considerably between 2003 and 2006 (Escherichia coli, 4.9%-8.3%; Klebsiella spp., 17.8%-26.9%), doripenem inhibited 100% of strains confirmed as ESBL producers at ≤2 mg/L.