Activity of doripenem against anaerobic bacteria

• Published in: Pathologie biologie (Paris) Vol. 59; no. 2; pp. 102 - 107
• Main Authors: Dubreuil, L, Neut, C, Mahieux, S, Muller-Serieys, C, Jean-Pierre, H, Marchandin, H, Soussy, C J, Miara, A
• Format: Journal Article
• Language: French
• Published: France 01.04.2011
• Subjects: Anti-Bacterial Agents - pharmacology; Bacteria, Anaerobic - drug effects; Bacterial Infections - microbiology; Bacteroides fragilis - drug effects; Carbapenems - pharmacology; Drug Resistance, Microbial; Drug Resistance, Multiple, Bacterial; Gram-Positive Bacteria - drug effects; Humans; Imipenem - pharmacology; Microbial Sensitivity Tests
• ISSN: 1768-3114
• DOI: 10.1016/j.patbio.2010.03.006

This study examines the activity of doripenem, a new carbapenem compound compared with amoxicillin-clavulanic acid, piperacillin+tazobactam, imipenem, clindamycin and metronidazole against 316 anaerobes. Inoculum preparation and agar dilution method were performed according to the CLSI method for anaerobes (M11A7). At a concentration of 4μg/ml doripenem and imipenem (IMP) inhibited 122 (96 %) and 126 (99 %) strains of the Bacteroides fragilis group, respectively. In contrast, doripenem appeared more potent than IMP against Gram-positive anaerobes inhibiting at the same concentration of 4μg/ml 145/145 strains (100 %) versus 115/145 for IMP (79.3 %). Against 316 anaerobic strains, the carbapenem doripenem had an MIC(50) of 0.25μg/ml and an MIC(90) of 2μg/ml. Results were similar to those for imipenem (MIC(50) of 0.125μg/ml and MIC(90) of 4μg/ml). If we consider the resistant breakpoints of the two carbapenems as defined by EUCAST, the resistance rate for doripenem (MIC>4μg/ml) 1.6 % is similar to that of imipenem (MIC>8μg/ml) 1.3 %. Thus independently of the PK/PD parameters the two carbapenems demonstrated very close activity; doripenem was more potent on Gram-positive anaerobes and slightly less potent against Gram-negative anaerobes mainly the B. fragilis group. Further clinical studies are needed to assess its usefulness in patients.